library.js

// An implementation of a libc for the web. Basically, implementations of
// the various standard C libraries, that can be called from compiled code,
// and work using the actual JavaScript environment.
//
// We search the Library object when there is an external function. If the
// entry in the Library is a function, we insert it. If it is a string, we
// do another lookup in the library (a simple way to write a function once,
// if it can be called by different names). We also allow dependencies,
// using __deps. Initialization code to be run after allocating all
// global constants can be defined by __postset.
//
// Note that the full function name will be '_' + the name in the Library
// object. For convenience, the short name appears here. Note that if you add a
// new function with an '_', it will not be found.

LibraryManager.library = {
  // ==========================================================================
  // File system base.
  // ==========================================================================

  stdin: 0,
  stdout: 0,
  stderr: 0,

  $FS__deps: ['$ERRNO_CODES', '__setErrNo', 'stdin', 'stdout', 'stderr'],
  $FS__postset: 'FS.init();',
  $FS: {
    // The main file system tree. All the contents are inside this.
    root: {
      read: true,
      write: false,
      isFolder: true,
      isDevice: false,
      timestamp: new Date().getTime(),
      inodeNumber: 1,
      contents: {}
    },
    // The path to the current folder.
    currentPath: '/',
    // The inode to assign to the next created object.
    nextInode: 2,
    // The file creation mask used by the program.
    cmask: 0x1ff,  // S_IRWXU | S_IRWXG | S_IRWXO.
    // Currently opened file or directory streams. Padded with null so the zero
    // index is unused, as the indices are used as pointers. This is not split
    // into separate fileStreams and folderStreams lists because the pointers
    // must be interchangeable, e.g. when used in fdopen().
    streams: [null],
    // Whether we are currently ignoring permissions. Useful when preparing the
    // filesystem and creating files inside read-only folders.
    ignorePermissions: true,
    // Converts any path to an absolute path. Resolves embedded "." and ".."
    // parts.
    absolutePath: function(relative, base) {
      if (typeof relative !== 'string') return null;
      if (base === undefined) base = FS.currentPath;
      if (relative && relative[0] == '/') base = '';
      var full = base + '/' + relative;
      var parts = full.split('/').reverse();
      var absolute = [''];
      while (parts.length) {
        var part = parts.pop();
        if (part == '' || part == '.') {
          // Nothing.
        } else if (part == '..') {
          if (absolute.length > 1) absolute.pop();
        } else {
          absolute.push(part);
        }
      }
      return absolute.length == 1 ? '/' : absolute.join('/');
    },
    // Analyzes a relative or absolute path returning a description, containing:
    //   isRoot: Whether the path points to the root.
    //   exists: Whether the object at the path exists.
    //   error: If !exists, this will contain the errno code of the cause.
    //   name: The base name of the object (null if !parentExists).
    //   path: The absolute path to the object, with all links resolved.
    //   object: The filesystem record of the object referenced by the path.
    //   parentExists: Whether the parent of the object exist and is a folder.
    //   parentPath: The absolute path to the parent folder.
    //   parentObject: The filesystem record of the parent folder.
    analyzePath: function(path, dontResolveLastLink, linksVisited) {
      var ret = {
        isRoot: false,
        exists: false,
        error: 0,
        name: null,
        path: null,
        object: null,
        parentExists: false,
        parentPath: null,
        parentObject: null
      };
      path = FS.absolutePath(path);
      if (path == '/') {
        ret.isRoot = true;
        ret.exists = ret.parentExists = true;
        ret.name = '/';
        ret.path = ret.parentPath = '/';
        ret.object = ret.parentObject = FS.root;
      } else if (path !== null) {
        linksVisited = linksVisited || 0;
        path = path.slice(1).split('/');
        var current = FS.root;
        var traversed = [''];
        while (path.length) {
          if (path.length == 1 && current.isFolder) {
            ret.parentExists = true;
            ret.parentPath = traversed.length == 1 ? '/' : traversed.join('/');
            ret.parentObject = current;
            ret.name = path[0];
          }
          var target = path.shift();
          if (!current.isFolder) {
            ret.error = ERRNO_CODES.ENOTDIR;
            break;
          } else if (!current.read) {
            ret.error = ERRNO_CODES.EACCES;
            break;
          } else if (!current.contents.hasOwnProperty(target)) {
            ret.error = ERRNO_CODES.ENOENT;
            break;
          }
          current = current.contents[target];
          if (current.link && !(dontResolveLastLink && path.length == 0)) {
            if (linksVisited > 40) { // Usual Linux SYMLOOP_MAX.
              ret.error = ERRNO_CODES.ELOOP;
              break;
            }
            var link = FS.absolutePath(current.link, traversed.join('/'));
            return FS.analyzePath([link].concat(path).join('/'),
                                  dontResolveLastLink, linksVisited + 1);
          }
          traversed.push(target);
          if (path.length == 0) {
            ret.exists = true;
            ret.path = traversed.join('/');
            ret.object = current;
          }
        }
        return ret;
      }
      return ret;
    },
    // Finds the file system object at a given path. If dontResolveLastLink is
    // set to true and the object is a symbolic link, it will be returned as is
    // instead of being resolved. Links embedded in the path as still resolved.
    findObject: function(path, dontResolveLastLink) {
      var ret = FS.analyzePath(path, dontResolveLastLink);
      if (ret.exists) {
        return ret.object;
      } else {
        ___setErrNo(ret.error);
        return null;
      }
    },
    // Creates a file system record: file, link, device or folder.
    createObject: function(parent, name, properties, canRead, canWrite) {
      if (!parent) parent = '/';
      if (typeof parent === 'string') parent = FS.findObject(parent);

      if (!parent) {
        ___setErrNo(ERRNO_CODES.EACCES);
        throw new Error('Parent path must exist.');
      }
      if (!parent.isFolder) {
        ___setErrNo(ERRNO_CODES.ENOTDIR);
        throw new Error('Parent must be a folder.');
      }
      if (!parent.write && !FS.ignorePermissions) {
        ___setErrNo(ERRNO_CODES.EACCES);
        throw new Error('Parent folder must be writeable.');
      }
      if (!name || name == '.' || name == '..') {
        ___setErrNo(ERRNO_CODES.ENOENT);
        throw new Error('Name must not be empty.');
      }
      if (parent.contents.hasOwnProperty(name)) {
        ___setErrNo(ERRNO_CODES.EEXIST);
        throw new Error("Can't overwrite object.");
      }

      parent.contents[name] = {
        read: canRead === undefined ? true : canRead,
        write: canWrite === undefined ? false : canWrite,
        timestamp: new Date().getTime(),
        inodeNumber: FS.nextInode++
      };
      for (var key in properties) {
        if (properties.hasOwnProperty(key)) {
          parent.contents[name][key] = properties[key];
        }
      }

      return parent.contents[name];
    },
    // Creates a folder.
    createFolder: function(parent, name, canRead, canWrite) {
      var properties = {isFolder: true, isDevice: false, contents: {}};
      return FS.createObject(parent, name, properties, canRead, canWrite);
    },
    // Creates a a folder and all its missing parents.
    createPath: function(parent, path, canRead, canWrite) {
      var current = FS.findObject(parent);
      if (current === null) throw new Error('Invalid parent.');
      path = path.split('/').reverse();
      while (path.length) {
        var part = path.pop();
        if (!part) continue;
        if (!current.contents.hasOwnProperty(part)) {
          FS.createFolder(current, part, canRead, canWrite);
        }
        current = current.contents[part];
      }
      return current;
    },

    // Creates a file record, given specific properties.
    createFile: function(parent, name, properties, canRead, canWrite) {
      properties.isFolder = false;
      return FS.createObject(parent, name, properties, canRead, canWrite);
    },
    // Creates a file record from existing data.
    createDataFile: function(parent, name, data, canRead, canWrite) {
      if (typeof data === 'string') {
        var dataArray = [];
        for (var i = 0; i < data.length; i++) dataArray.push(data.charCodeAt(i));
        data = dataArray;
      }
      var properties = {isDevice: false, contents: data};
      return FS.createFile(parent, name, properties, canRead, canWrite);
    },
    // Creates a file record for lazy-loading from a URL.
    createLazyFile: function(parent, name, url, canRead, canWrite) {
      var properties = {isDevice: false, url: url};
      return FS.createFile(parent, name, properties, canRead, canWrite);
    },
    // Creates a link to a sepcific local path.
    createLink: function(parent, name, target, canRead, canWrite) {
      var properties = {isDevice: false, link: target};
      return FS.createFile(parent, name, properties, canRead, canWrite);
    },
    // Creates a character device with input and output callbacks:
    //   input: Takes no parameters, returns a byte value or null if no data is
    //          currently available.
    //   output: Takes a byte value; doesn't return anything. Can also be passed
    //           null to perform a flush of any cached data.
    createDevice: function(parent, name, input, output) {
      if (!(input || output)) {
        throw new Error('A device must have at least one callback defined.');
      }
      var ops = {isDevice: true, input: input, output: output};
      return FS.createFile(parent, name, ops, Boolean(input), Boolean(output));
    },
    // Makes sure a file's contents are loaded. Returns whether the file has
    // been loaded successfully. No-op for files that have been loaded already.
    forceLoadFile: function(obj) {
      if (obj.isDevice || obj.isFolder || obj.link ||
          'contents' in obj) return true;
      var success = true;
      if (typeof XMLHttpRequest !== 'undefined') {
        // Browser.
        // TODO: Use mozResponseArrayBuffer, responseStream, etc. if available.
        var xhr = new XMLHttpRequest();
        xhr.open('GET', obj.url, false);
        xhr.responseType = 'arraybuffer'; // hint to the browser that we want binary data
        xhr.overrideMimeType('text/plain; charset=x-user-defined');  // another hint
        xhr.send(null);
        if (xhr.status != 200 && xhr.status != 0) success = false;
        if (xhr.response) {
          obj.contents = new Uint8Array(xhr.response);
        } else {
          obj.contents = intArrayFromString(xhr.responseText || '', true);
        }
      } else if (typeof read !== 'undefined') {
        // Command-line.
        try {
          obj.contents = intArrayFromString(read(obj.url), true);
        } catch (e) {
          success = false;
        }
      } else {
        throw new Error('Cannot load without read() or XMLHttpRequest.');
      }
      if (!success) ___setErrNo(ERRNO_CODES.EIO);
      return success;
    },
    // Initializes the filesystems with stdin/stdout/stderr devices, given
    // optional handlers.
    init: function(input, output, error) {
      // Make sure we initialize only once.
      if (FS.init.initialized) return;
      else FS.init.initialized = true;

      // Default handlers.
      if (!input) input = function() {
        if (!input.cache) {
          var result;
          if (window && typeof window.prompt == 'function') {
            // Browser.
            result = window.prompt('Input: ');
          } else if (typeof readline == 'function') {
            // Command line.
            result = readline();
          }
          if (!result) return null;
          input.cache = intArrayFromString(result + '\n', true);
        }
        return input.cache.shift();
      };
      if (!output) output = function(val) {
        if (!output.printer) {
          if (typeof print == 'function') {
            // Either console or custom print function defined.
            output.printer = print;
          } else if (console && typeof console.log == 'function') {
            // Browser-like environment with a console.
            output.printer = console.log;
          } else {
            // Fallback to a harmless no-op.
            output.printer = function() {};
          }
        }
        if (!output.buffer) output.buffer = [];
        if (val === null || val === '\n'.charCodeAt(0)) {
          output.printer(output.buffer.join(''));
          output.buffer = [];
        } else {
          output.buffer.push(String.fromCharCode(val));
        }
      };
      if (!error) error = output;

      // Create the temporary folder.
      FS.createFolder('/', 'tmp', true, true);

      // Create the I/O devices.
      var devFolder = FS.createFolder('/', 'dev', true, false);
      var stdin = FS.createDevice(devFolder, 'stdin', input);
      var stdout = FS.createDevice(devFolder, 'stdout', null, output);
      var stderr = FS.createDevice(devFolder, 'stderr', null, error);
      FS.createDevice(devFolder, 'tty', input, output);

      // Create default streams.
      FS.streams[1] = {
        path: '/dev/stdin',
        object: stdin,
        position: 0,
        isRead: true,
        isWrite: false,
        isAppend: false,
        error: false,
        eof: false,
        ungotten: []
      };
      FS.streams[2] = {
        path: '/dev/stdout',
        object: stdout,
        position: 0,
        isRead: false,
        isWrite: true,
        isAppend: false,
        error: false,
        eof: false,
        ungotten: []
      };
      FS.streams[3] = {
        path: '/dev/stderr',
        object: stderr,
        position: 0,
        isRead: false,
        isWrite: true,
        isAppend: false,
        error: false,
        eof: false,
        ungotten: []
      };
      _stdin = allocate([1], 'void*', ALLOC_STATIC);
      _stdout = allocate([2], 'void*', ALLOC_STATIC);
      _stderr = allocate([3], 'void*', ALLOC_STATIC);

      // Once initialized, permissions start having effect.
      FS.ignorePermissions = false;
    }
  },

  // ==========================================================================
  // dirent.h
  // ==========================================================================

  __dirent_struct_layout: Runtime.generateStructInfo(null, '%struct.dirent'),
  opendir__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', '__dirent_struct_layout'],
  opendir: function(dirname) {
    // DIR *opendir(const char *dirname);
    // http://pubs.opengroup.org/onlinepubs/007908799/xsh/opendir.html
    // NOTE: Calculating absolute path redundantly since we need to associate it
    //       with the opened stream.
    var path = FS.absolutePath(Pointer_stringify(dirname));
    if (path === null) {
      ___setErrNo(ERRNO_CODES.ENOENT);
      return 0;
    }
    var target = FS.findObject(path);
    if (target === null) return 0;
    if (!target.isFolder) {
      ___setErrNo(ERRNO_CODES.ENOTDIR);
      return 0;
    } else if (!target.read) {
      ___setErrNo(ERRNO_CODES.EACCES);
      return 0;
    }
    var id = FS.streams.length;
    var contents = [];
    for (var key in target.contents) contents.push(key);
    FS.streams[id] = {
      path: path,
      object: target,
      // An index into contents. Special values: -2 is ".", -1 is "..".
      position: -2,
      isRead: true,
      isWrite: false,
      isAppend: false,
      error: false,
      eof: false,
      ungotten: [],
      // Folder-specific properties:
      // Remember the contents at the time of opening in an array, so we can
      // seek between them relying on a single order.
      contents: contents,
      // Each stream has its own area for readdir() returns.
      currentEntry: _malloc(___dirent_struct_layout.__size__)
    };
    return id;
  },
  closedir__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  closedir: function(dirp) {
    // int closedir(DIR *dirp);
    // http://pubs.opengroup.org/onlinepubs/007908799/xsh/closedir.html
    if (!FS.streams[dirp] || !FS.streams[dirp].object.isFolder) {
      return ___setErrNo(ERRNO_CODES.EBADF);
    } else {
      _free(FS.streams[dirp].currentEntry);
      delete FS.streams[dirp];
      return 0;
    }
  },
  telldir__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  telldir: function(dirp) {
    // long int telldir(DIR *dirp);
    // http://pubs.opengroup.org/onlinepubs/007908799/xsh/telldir.html
    if (!FS.streams[dirp] || !FS.streams[dirp].object.isFolder) {
      return ___setErrNo(ERRNO_CODES.EBADF);
    } else {
      return FS.streams[dirp].position;
    }
  },
  seekdir__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  seekdir: function(dirp, loc) {
    // void seekdir(DIR *dirp, long int loc);
    // http://pubs.opengroup.org/onlinepubs/007908799/xsh/seekdir.html
    if (!FS.streams[dirp] || !FS.streams[dirp].object.isFolder) {
      ___setErrNo(ERRNO_CODES.EBADF);
    } else {
      var entries = 0;
      for (var key in FS.streams[dirp].contents) entries++;
      if (loc >= entries) {
        ___setErrNo(ERRNO_CODES.EINVAL);
      } else {
        FS.streams[dirp].position = loc;
      }
    }
  },
  rewinddir__deps: ['seekdir'],
  rewinddir: function(dirp) {
    // void rewinddir(DIR *dirp);
    // http://pubs.opengroup.org/onlinepubs/007908799/xsh/rewinddir.html
    _seekdir(dirp, -2);
  },
  readdir_r__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', '__dirent_struct_layout'],
  readdir_r: function(dirp, entry, result) {
    // int readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result);
    // http://pubs.opengroup.org/onlinepubs/007908799/xsh/readdir_r.html
    if (!FS.streams[dirp] || !FS.streams[dirp].object.isFolder) {
      return ___setErrNo(ERRNO_CODES.EBADF);
    }
    var stream = FS.streams[dirp];
    var loc = stream.position;
    var entries = 0;
    for (var key in stream.contents) entries++;
    if (loc < -2 || loc >= entries) {
      {{{ makeSetValue('result', '0', '0', 'i8*') }}}
    } else {
      var name, inode;
      if (loc === -2) {
        name = '.';
        inode = 1;  // Really undefined.
      } else if (loc === -1) {
        name = '..';
        inode = 1;  // Really undefined.
      } else {
        name = stream.contents[loc];
        inode = stream.object.contents[name].inodeNumber;
      }
      stream.position++;
      var offsets = ___dirent_struct_layout;
      {{{ makeSetValue('entry', 'offsets.d_ino', 'inode', 'i32') }}}
      {{{ makeSetValue('entry', 'offsets.d_off', 'stream.position', 'i32') }}}
      {{{ makeSetValue('entry', 'offsets.d_reclen', 'name.length + 1', 'i32') }}}
      for (var i = 0; i < name.length; i++) {
        {{{ makeSetValue('entry + offsets.d_name', 'i', 'name.charCodeAt(i)', 'i8') }}}
      }
      {{{ makeSetValue('entry + offsets.d_name', 'i', '0', 'i8') }}}
      var type = stream.object.isDevice ? 2 // DT_CHR, character device.
               : stream.object.isFolder ? 4 // DT_DIR, directory.
               : stream.object.link !== undefined ? 10 // DT_LNK, symbolic link.
               : 8; // DT_REG, regular file.
      {{{ makeSetValue('entry', 'offsets.d_type', 'type', 'i8') }}}
      {{{ makeSetValue('result', '0', 'entry', 'i8*') }}}
    }
    return 0;
  },
  readdir__deps: ['readdir_r', '__setErrNo', '$ERRNO_CODES'],
  readdir: function(dirp) {
    // struct dirent *readdir(DIR *dirp);
    // http://pubs.opengroup.org/onlinepubs/007908799/xsh/readdir_r.html
    if (!FS.streams[dirp] || !FS.streams[dirp].object.isFolder) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return 0;
    } else {
      if (!_readdir.result) _readdir.result = _malloc(4);
      _readdir_r(dirp, FS.streams[dirp].currentEntry, _readdir.result);
      if ({{{ makeGetValue(0, '_readdir.result', 'i8*') }}} === 0) {
        return 0;
      } else {
        return FS.streams[dirp].currentEntry;
      }
    }
  },
  __01readdir64_: 'readdir',
  // TODO: Check if we need to link any other aliases.

  // ==========================================================================
  // utime.h
  // ==========================================================================

  __utimbuf_struct_layout: Runtime.generateStructInfo(null, '%struct.utimbuf'),
  utime__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', '__utimbuf_struct_layout'],
  utime: function(path, times) {
    // int utime(const char *path, const struct utimbuf *times);
    // http://pubs.opengroup.org/onlinepubs/009695399/basedefs/utime.h.html
    var time;
    if (times) {
      // NOTE: We don't keep track of access timestamps.
      var offset = ___utimbuf_struct_layout.modtime;
      time = {{{ makeGetValue('times', 'offset', 'i32') }}}
      time *= 1000;
    } else {
      time = new Date().getTime();
    }
    var file = FS.findObject(Pointer_stringify(path));
    if (file === null) return -1;
    if (!file.write) {
      ___setErrNo(ERRNO_CODES.EPERM);
      return -1;
    }
    file.timestamp = time;
    return 0;
  },

  // ==========================================================================
  // libgen.h
  // ==========================================================================

  __libgenSplitName: function(path) {
    if (path === 0 || {{{ makeGetValue('path', 0, 'i8') }}} === 0) {
      // Null or empty results in '.'.
      var me = ___libgenSplitName;
      if (!me.ret) {
        me.ret = allocate(['.'.charCodeAt(0), 0], 'i8', ALLOC_NORMAL);
      }
      return [me.ret, -1];
    } else {
      var slash = '/'.charCodeAt(0);
      var allSlashes = true;
      var slashPositions = [];
      for (var i = 0; {{{ makeGetValue('path', 'i', 'i8') }}} !== 0; i++) {
        if ({{{ makeGetValue('path', 'i', 'i8') }}} === slash) {
          slashPositions.push(i);
        } else {
          allSlashes = false;
        }
      }
      var length = i;
      if (allSlashes) {
        // All slashes result in a single slash.
        {{{ makeSetValue('path', '1', '0', 'i8') }}}
        return [path, -1];
      } else {
        // Strip trailing slashes.
        while (slashPositions.length &&
               slashPositions[slashPositions.length - 1] == length - 1) {
          {{{ makeSetValue('path', 'slashPositions.pop(i)', '0', 'i8') }}}
          length--;
        }
        return [path, slashPositions.pop()];
      }
    }
  },
  basename__deps: ['__libgenSplitName'],
  basename: function(path) {
    // char *basename(char *path);
    // http://pubs.opengroup.org/onlinepubs/007908799/xsh/basename.html
    var result = ___libgenSplitName(path);
    return result[0] + result[1] + 1;
  },
  __xpg_basename: 'basename',
  dirname__deps: ['__libgenSplitName'],
  dirname: function(path) {
    // char *dirname(char *path);
    // http://pubs.opengroup.org/onlinepubs/007908799/xsh/dirname.html
    var result = ___libgenSplitName(path);
    if (result[1] == 0) {
      {{{ makeSetValue('result[0]', 1, '0', 'i8') }}}
    } else if (result[1] !== -1) {
      {{{ makeSetValue('result[0]', 'result[1]', '0', 'i8') }}}
    }
    return result[0];
  },

  // ==========================================================================
  // sys/stat.h
  // ==========================================================================

  __stat_struct_layout: Runtime.generateStructInfo(null, '%struct.stat'),
  stat__deps: ['$FS', '__stat_struct_layout'],
  stat: function(path, buf, dontResolveLastLink) {
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/stat.html
    // int stat(const char *path, struct stat *buf);
    // NOTE: dontResolveLastLink is a shortcut for lstat(). It should never be
    //       used in client code.
    var obj = FS.findObject(Pointer_stringify(path), dontResolveLastLink);
    if (obj === null || !FS.forceLoadFile(obj)) return -1;

    var offsets = ___stat_struct_layout;

    // Constants.
    {{{ makeSetValue('buf', 'offsets.st_nlink', '1', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.st_uid', '0', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.st_gid', '0', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.st_blksize', '4096', 'i32') }}}

    // Variables.
    {{{ makeSetValue('buf', 'offsets.st_ino', 'obj.inodeNumber', 'i32') }}}
    var time = Math.floor(obj.timestamp / 1000);
    if (offsets.st_atime === undefined) {
      offsets.st_atime = offsets.st_atim.tv_sec;
      offsets.st_mtime = offsets.st_mtim.tv_sec;
      offsets.st_ctime = offsets.st_ctim.tv_sec;
      var nanosec = (obj.timestamp % 1000) * 1000;
      {{{ makeSetValue('buf', 'offsets.st_atim.tv_nsec', 'nanosec', 'i32') }}}
      {{{ makeSetValue('buf', 'offsets.st_mtim.tv_nsec', 'nanosec', 'i32') }}}
      {{{ makeSetValue('buf', 'offsets.st_ctim.tv_nsec', 'nanosec', 'i32') }}}
    }
    {{{ makeSetValue('buf', 'offsets.st_atime', 'time', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.st_mtime', 'time', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.st_ctime', 'time', 'i32') }}}
    var mode = 0;
    var size = 0;
    var blocks = 0;
    var dev = 0;
    var rdev = 0;
    if (obj.isDevice) {
      //  Device numbers reuse inode numbers.
      dev = rdev = obj.inodeNumber;
      size = blocks = 0;
      mode = 0x2000;  // S_IFCHR.
    } else {
      dev = 1;
      rdev = 0;
      // NOTE: In our implementation, st_blocks = Math.ceil(st_size/st_blksize),
      //       but this is not required by the standard.
      if (obj.isFolder) {
        size = 4096;
        blocks = 1;
        mode = 0x4000;  // S_IFDIR.
      } else {
        var data = obj.contents || obj.link;
        size = data.length;
        blocks = Math.ceil(data.length / 4096);
        mode = obj.link === undefined ? 0x8000 : 0xA000;  // S_IFREG, S_IFLNK.
      }
    }
    {{{ makeSetValue('buf', 'offsets.st_dev', 'dev', 'i64') }}}
    {{{ makeSetValue('buf', 'offsets.st_rdev', 'rdev', 'i64') }}}
    // NOTE: These two may be i64, depending on compilation options.
    {{{ makeSetValue('buf', 'offsets.st_size', 'size', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.st_blocks', 'blocks', 'i32') }}}
    if (obj.read) mode |= 0x16D;  // S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH.
    if (obj.write) mode |= 0x92;  // S_IWUSR | S_IWGRP | S_IWOTH.
    {{{ makeSetValue('buf', 'offsets.st_mode', 'mode', 'i32') }}}

    return 0;
  },
  lstat__deps: ['stat'],
  lstat: function(path, buf) {
    // int lstat(const char *path, struct stat *buf);
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/lstat.html
    return _stat(path, buf, true);
  },
  fstat__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', 'stat'],
  fstat: function(fildes, buf) {
    // int fstat(int fildes, struct stat *buf);
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/fstat.html
    if (!FS.streams[fildes]) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    } else {
      var pathArray = intArrayFromString(FS.streams[fildes].path);
      var pathPtr = allocate(pathArray, 'i8', ALLOC_NORMAL);
      var result = _stat(pathPtr, buf);
      _free(pathPtr);
      return result;
    }
  },
  mknod__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  mknod: function(path, mode, dev) {
    // int mknod(const char *path, mode_t mode, dev_t dev);
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/mknod.html
    if (dev !== 0 || !(mode & 0xC000)) {  // S_IFREG | S_IFDIR.
      // Can't create devices or pipes through mknod().
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    } else {
      var properties = {contents: [], isFolder: Boolean(mode & 0x4000)};  // S_IFDIR.
      path = FS.analyzePath(Pointer_stringify(path));
      try {
        FS.createObject(path.parentObject, path.name, properties,
                        mode & 0x100, mode & 0x80);  // S_IRUSR, S_IWUSR.
        return 0;
      } catch (e) {
        return -1;
      }
    }
  },
  mkdir__deps: ['mknod'],
  mkdir: function(path, mode) {
    // int mkdir(const char *path, mode_t mode);
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/mkdir.html
    return _mknod(path, 0x4000 | (mode & 0x180), 0);  // S_IFDIR, S_IRUSR | S_IWUSR.
  },
  mkfifo__deps: ['__setErrNo', '$ERRNO_CODES'],
  mkfifo: function(path, mode) {
    // int mkfifo(const char *path, mode_t mode);
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/mkfifo.html
    // NOTE: We support running only a single process, and named pipes require
    //       blocking, which we can't provide. The error code is not very
    //       accurate, but it's the closest among those allowed in the standard
    //       and unlikely to result in retries.
    ___setErrNo(ERRNO_CODES.EROFS);
    return -1;
  },
  chmod__deps: ['$FS'],
  chmod: function(path, mode) {
    // int chmod(const char *path, mode_t mode);
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/chmod.html
    var obj = FS.findObject(Pointer_stringify(path));
    if (obj === null) return -1;
    obj.read = mode & 0x100;  // S_IRUSR.
    obj.write = mode & 0x80;  // S_IWUSR.
    obj.timestamp = new Date().getTime();
    return 0;
  },
  fchmod__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', 'chmod'],
  fchmod: function(fildes, mode) {
    // int fchmod(int fildes, mode_t mode);
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/fchmod.html
    if (!FS.streams[fildes]) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    } else {
      var pathArray = intArrayFromString(FS.streams[fildes].path);
      var pathPtr = allocate(pathArray, 'i8', ALLOC_NORMAL);
      var result = _chmod(pathPtr, mode);
      _free(pathPtr);
      return result;
    }
  },
  // TODO: Test once cmask is used.
  umask__deps: ['$FS'],
  umask: function(newMask) {
    var oldMask = FS.cmask;
    FS.cmask = newMask;
    return oldMask;
  },
  __01fstat64_: 'fstat',
  __01stat64_: 'stat',
  __01lstat64_: 'lstat',
  // TODO: Check if other aliases are needed.

  // ==========================================================================
  // sys/statvfs.h
  // ==========================================================================

  __statvfs_struct_layout: Runtime.generateStructInfo(null, '%struct.statvfs'),
  statvfs__deps: ['$FS', '__statvfs_struct_layout'],
  statvfs: function(path, buf) {
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/stat.html
    // int statvfs(const char *restrict path, struct statvfs *restrict buf);
    var offsets = ___statvfs_struct_layout;
    // NOTE: None of the constants here are true. We're just returning safe and
    //       sane values.
    {{{ makeSetValue('buf', 'offsets.f_bsize', '4096', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.f_frsize', '4096', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.f_blocks', '1000000', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.f_bfree', '500000', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.f_bavail', '500000', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.f_files', 'FS.nextInode', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.f_ffree', '1000000', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.f_favail', '1000000', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.f_fsid', '42', 'i32') }}}
    {{{ makeSetValue('buf', 'offsets.f_flag', '2', 'i32') }}}  // ST_NOSUID
    {{{ makeSetValue('buf', 'offsets.f_namemax', '255', 'i32') }}}
    return 0;
  },
  fstatvfs__deps: ['statvfs'],
  fstatvfs: function(fildes, buf) {
    // int fstatvfs(int fildes, struct statvfs *buf);
    // http://pubs.opengroup.org/onlinepubs/009604499/functions/statvfs.html
    return _statvfs(0, buf);
  },
  __01statvfs64_: 'statvfs',
  __01fstatvfs64_: 'fstatvfs',

  // ==========================================================================
  // fcntl.h
  // ==========================================================================

  __flock_struct_layout: Runtime.generateStructInfo(null, '%struct.flock'),
  open__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', '__dirent_struct_layout'],
  open: function(path, oflag, mode) {
    // int open(const char *path, int oflag, ...);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/open.html
    // NOTE: This implementation tries to mimic glibc rather that strictly
    // following the POSIX standard.

    // Simplify flags.
    var accessMode = oflag & 0x3;  // O_ACCMODE.
    var isWrite = accessMode != 0x0;  // O_RDONLY.
    var isRead = accessMode != 0x1;  // O_WRONLY.
    var isCreate = Boolean(oflag & 0x40);  // O_CREAT.
    var isExistCheck = Boolean(oflag & 0x80);  // O_EXCL.
    var isTruncate = Boolean(oflag & 0x200);  // O_TRUNC.
    var isAppend = Boolean(oflag & 0x400);  // O_APPEND.

    // Verify path.
    var origPath = path;
    path = FS.analyzePath(Pointer_stringify(path));
    if (!path.parentExists) {
      ___setErrNo(path.error);
      return -1;
    }
    var target = path.object || null;

    // Verify the file exists, create if needed and allowed.
    if (target) {
      if (isCreate && isExistCheck) {
        ___setErrNo(ERRNO_CODES.EEXIST);
        return -1;
      }
      if ((isWrite || isCreate || isTruncate) && target.isFolder) {
        ___setErrNo(ERRNO_CODES.EISDIR);
        return -1;
      }
      if (isRead && !target.read || isWrite && !target.write) {
        ___setErrNo(ERRNO_CODES.EACCES);
        return -1;
      }
      if (isTruncate && !target.isDevice) {
        target.contents = [];
      } else {
        if (!FS.forceLoadFile(target)) {
          ___setErrNo(ERRNO_CODES.EIO);
          return -1;
        }
      }
    } else {
      if (!isCreate) {
        ___setErrNo(ERRNO_CODES.ENOENT);
        return -1;
      }
      if (!path.parentObject.write) {
        ___setErrNo(ERRNO_CODES.EACCES);
        return -1;
      }
      target = FS.createDataFile(path.parentObject, path.name, [],
                                 mode & 0x100, mode & 0x80);  // S_IRUSR, S_IWUSR.
    }
    // Actually create an open stream.
    var id = FS.streams.length;
    if (target.isFolder) {
      var entryBuffer = 0;
      if (___dirent_struct_layout) {
        entryBuffer = _malloc(___dirent_struct_layout.__size__);
      }
      var contents = [];
      for (var key in target.contents) contents.push(key);
      FS.streams[id] = {
        path: path.path,
        object: target,
        // An index into contents. Special values: -2 is ".", -1 is "..".
        position: -2,
        isRead: true,
        isWrite: false,
        isAppend: false,
        error: false,
        eof: false,
        ungotten: [],
        // Folder-specific properties:
        // Remember the contents at the time of opening in an array, so we can
        // seek between them relying on a single order.
        contents: contents,
        // Each stream has its own area for readdir() returns.
        currentEntry: entryBuffer
      };
    } else {
      FS.streams[id] = {
        path: path.path,
        object: target,
        position: 0,
        isRead: isRead,
        isWrite: isWrite,
        isAppend: isAppend,
        error: false,
        eof: false,
        ungotten: []
      };
    }
    return id;
  },
  creat__deps: ['open'],
  creat: function(path, mode) {
    // int creat(const char *path, mode_t mode);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/creat.html
    return _open(path, 0x241, mode);  // O_WRONLY | O_CREAT | O_TRUNC.
  },
  fcntl__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', '__flock_struct_layout'],
  fcntl: function(fildes, cmd, arg) {
    // int fcntl(int fildes, int cmd, ...);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/fcntl.html
    if (!(fildes in FS.streams)) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
    var stream = FS.streams[fildes];
    switch (cmd) {
      case 0:  // F_DUPFD.
        if (arg < 0) {
          ___setErrNo(ERRNO_CODES.EINVAL);
          return -1;
        }
        var newStream = {};
        for (var member in stream) {
          newStream[member] = stream[member];
        }
        if (arg in FS.streams) arg = FS.streams.length;
        FS.streams[arg] = newStream;
        return arg;
      case 1:  // F_GETFD.
      case 2:  // F_SETFD.
        return 0;  // FD_CLOEXEC makes no sense for a single process.
      case 3:  // F_GETFL.
        var flags = 0;
        if (stream.isRead && stream.isWrite) flags = 0x2;  // O_RDWR.
        else if (!stream.isRead && stream.isWrite) flags = 0x1;  // O_WRONLY.
        else if (stream.isRead && !stream.isWrite) flags = 0x0;  // O_RDONLY.
        if (stream.isAppend) flags |= 0x400;  // O_APPEND.
        // Synchronization and blocking flags are irrelevant to us.
        return flags;
      case 4:  // F_SETFL.
        stream.isAppend = Boolean(arg | 0x400);  // O_APPEND.
        // Synchronization and blocking flags are irrelevant to us.
        return 0;
      case 5:  // F_GETLK.
        var offset = ___flock_struct_layout.l_type;
        // We're always unlocked.
        {{{ makeSetValue('arg', 'offset', '2', 'i16') }}}  // F_UNLCK.
        return 0;
      case 6:  // F_SETLK.
      case 7:  // F_SETLKW.
        // Pretend that the locking is successful.
        return 0;
      case 8:  // F_SETOWN.
      case 9:  // F_GETOWN.
        // These are for sockets. We don't have them implemented (yet?).
        ___setErrNo(ERRNO_CODES.EINVAL);
        return -1;
      default:
        ___setErrNo(ERRNO_CODES.EINVAL);
        return -1;
    }
    // Should never be reached. Only to silence strict warnings.
    return -1;
  },
  posix_fadvise: function(fd, offset, len, advice) {
    // int posix_fadvise(int fd, off_t offset, off_t len, int advice);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/posix_fadvise.html
    // Advise as much as you wish. We don't care.
    return 0;
  },
  posix_madvise: 'posix_fadvise',
  posix_fallocate__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  posix_fallocate: function(fd, offset, len) {
    // int posix_fallocate(int fd, off_t offset, off_t len);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/posix_fallocate.html
    if (!(fd in FS.streams) || FS.streams[fd].link ||
        FS.streams[fd].isFolder || FS.streams[fd].isDevice) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
    var contents = FS.streams[fd].object.contents;
    var limit = offset + len;
    while (limit > contents.length) contents.push(0);
    return 0;
  },

  // ==========================================================================
  // poll.h
  // ==========================================================================

  __pollfd_struct_layout: Runtime.generateStructInfo(null, '%struct.pollfd'),
  poll__deps: ['$FS', '__pollfd_struct_layout'],
  poll: function(fds, nfds, timeout) {
    // int poll(struct pollfd fds[], nfds_t nfds, int timeout);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/poll.html
    // NOTE: This is pretty much a no-op mimicing glibc.
    var offsets = ___pollfd_struct_layout;
    var nonzero = 0;
    for (var i = 0; i < nfds; i++) {
      var pollfd = fds + ___pollfd_struct_layout.__size__ * i;
      var fd = {{{ makeGetValue('pollfd', 'offsets.fd', 'i32') }}};
      var events = {{{ makeGetValue('pollfd', 'offsets.events', 'i16') }}};
      var revents = 0;
      if (fd in FS.streams) {
        var stream = FS.streams[fd];
        if (events & 0x1) revents |= 0x1;  // POLLIN.
        if (events & 0x4) revents |= 0x4;  // POLLOUT.
      } else {
        if (events & 0x20) revents |= 0x20;  // POLLNVAL.
      }
      if (revents) nonzero++;
      {{{ makeSetValue('pollfd', 'offsets.revents', 'revents', 'i16') }}}
    }
    return nonzero;
  },

  // ==========================================================================
  // unistd.h
  // ==========================================================================

  access__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  access: function(path, amode) {
    // int access(const char *path, int amode);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/access.html
    path = Pointer_stringify(path);
    var target = FS.findObject(path);
    if (target === null) return -1;
    if ((amode & 2 && !target.write) ||  // W_OK.
        ((amode & 1 || amode & 4) && !target.read)) {  // X_OK, R_OK.
      ___setErrNo(ERRNO_CODES.EACCES);
      return -1;
    } else {
      return 0;
    }
  },
  chdir__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  chdir: function(path) {
    // int chdir(const char *path);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/chdir.html
    // NOTE: The path argument may be a string, to simplify fchdir().
    if (typeof path !== 'string') path = Pointer_stringify(path);
    path = FS.analyzePath(path);
    if (!path.exists) {
      ___setErrNo(path.error);
      return -1;
    } else if (!path.object.isFolder) {
      ___setErrNo(ERRNO_CODES.ENOTDIR);
      return -1;
    } else {
      FS.currentPath = path.path;
      return 0;
    }
  },
  chown__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  chown: function(path, owner, group, dontResolveLastLink) {
    // int chown(const char *path, uid_t owner, gid_t group);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/chown.html
    // We don't support multiple users, so changing ownership makes no sense.
    // NOTE: The path argument may be a string, to simplify fchown().
    // NOTE: dontResolveLastLink is a shortcut for lchown(). It should never be
    //       used in client code.
    if (typeof path !== 'string') path = Pointer_stringify(path);
    var target = FS.findObject(path, dontResolveLastLink);
    if (target === null) return -1;
    target.timestamp = new Date().getTime();
    return 0;
  },
  chroot__deps: ['__setErrNo', '$ERRNO_CODES'],
  chroot: function(path) {
    // int chroot(const char *path);
    // http://pubs.opengroup.org/onlinepubs/7908799/xsh/chroot.html
    ___setErrNo(ERRNO_CODES.EACCES);
    return -1;
  },
  close__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  close: function(fildes) {
    // int close(int fildes);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/close.html
    if (FS.streams[fildes]) {
      if (FS.streams[fildes].currentEntry) {
        _free(FS.streams[fildes].currentEntry);
      }
      delete FS.streams[fildes];
      return 0;
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  dup__deps: ['fcntl'],
  dup: function(fildes) {
    // int dup(int fildes);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/dup.html
    return _fcntl(fildes, 0, 0);  // F_DUPFD.
  },
  dup2__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', 'fcntl', 'close'],
  dup2: function(fildes, fildes2) {
    // int dup2(int fildes, int fildes2);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/dup.html
    if (fildes2 < 0) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    } else if (fildes === fildes2 && FS.streams[fildes]) {
      return fildes;
    } else {
      _close(fildes2);
      return _fcntl(fildes, 0, fildes2);  // F_DUPFD.
    }
  },
  fchown__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', 'chown'],
  fchown: function(fildes, owner, group) {
    // int fchown(int fildes, uid_t owner, gid_t group);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fchown.html
    if (FS.streams[fildes]) {
      return _chown(FS.streams[fildes].path, owner, group);
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  fchdir__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', 'chdir'],
  fchdir: function(fildes) {
    // int fchdir(int fildes);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fchdir.html
    if (FS.streams[fildes]) {
      return _chdir(FS.streams[fildes].path);
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  ctermid__deps: ['strcpy'],
  ctermid: function(s) {
    // char *ctermid(char *s);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/ctermid.html
    if (!_ctermid.ret) {
      var arr = intArrayFromString('/dev/tty');
      _ctermid.ret = allocate(arr, 'i8', ALLOC_NORMAL);
    }
    return s ? _strcpy(s, _ctermid.ret) : _ctermid.ret;
  },
  crypt: function(key, salt) {
    // char *(const char *, const char *);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/crypt.html
    // TODO: Implement (probably compile from C).
    ___setErrNo(ERRNO_CODES.ENOSYS);
    return 0;
  },
  encrypt: function(block, edflag) {
    // void encrypt(char block[64], int edflag);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/encrypt.html
    // TODO: Implement (probably compile from C).
    ___setErrNo(ERRNO_CODES.ENOSYS);
  },
  fpathconf__deps: ['__setErrNo', '$ERRNO_CODES'],
  fpathconf: function(fildes, name) {
    // long fpathconf(int fildes, int name);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/encrypt.html
    // NOTE: The first parameter is ignored, so pathconf == fpathconf.
    // The constants here aren't real values. Just mimicing glibc.
    switch (name) {
      case 0:  // _PC_LINK_MAX.
        return 32000;
      case 1:  // _PC_MAX_CANON.
      case 2:  // _PC_MAX_INPUT.
      case 3:  // _PC_NAME_MAX.
        return 255;
      case 4:  // _PC_PATH_MAX.
      case 5:  // _PC_PIPE_BUF.
      case 16:  // _PC_REC_MIN_XFER_SIZE.
      case 17:  // _PC_REC_XFER_ALIGN.
      case 18:  // _PC_ALLOC_SIZE_MIN.
        return 4096;
      case 6:  // _PC_CHOWN_RESTRICTED.
      case 7:  // _PC_NO_TRUNC.
      case 20:  // _PC_2_SYMLINKS.
        return 1;
      case 8:  // _PC_VDISABLE.
        return 0;
      case 9:  // _PC_SYNC_IO.
      case 10:  // _PC_ASYNC_IO.
      case 11:  // _PC_PRIO_IO.
      case 12:  // _PC_SOCK_MAXBUF.
      case 14:  // _PC_REC_INCR_XFER_SIZE.
      case 15:  // _PC_REC_MAX_XFER_SIZE.
      case 19:  // _PC_SYMLINK_MAX.
        return -1;
      case 13:  // _PC_FILESIZEBITS.
        return 64;
    }
    ___setErrNo(ERRNO_CODES.EINVAL);
    return -1;
  },
  pathconf: 'fpathconf',
  fsync__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  fsync: function(fildes) {
    // int fsync(int fildes);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fsync.html
    if (FS.streams[fildes]) {
      // We write directly to the file system, so there's nothing to do here.
      return 0;
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  fdatasync: 'fsync',
  truncate__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  truncate: function(path, length) {
    // int truncate(const char *path, off_t length);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/truncate.html
    // NOTE: The path argument may be a string, to simplify ftruncate().
    if (length < 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    } else {
      if (typeof path !== 'string') path = Pointer_stringify(path);
      var target = FS.findObject(path);
      if (target === null) return -1;
      if (target.isFolder) {
        ___setErrNo(ERRNO_CODES.EISDIR);
        return -1;
      } else if (target.isDevice) {
        ___setErrNo(ERRNO_CODES.EINVAL);
        return -1;
      } else if (!target.write) {
        ___setErrNo(ERRNO_CODES.EACCES);
        return -1;
      } else {
        var contents = target.contents;
        if (length < contents.length) contents.length = length;
        else while (length > contents.length) contents.push(0);
        target.timestamp = new Date().getTime();
        return 0;
      }
    }
  },
  ftruncate__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', 'truncate'],
  ftruncate: function(fildes, length) {
    // int ftruncate(int fildes, off_t length);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/ftruncate.html
    if (FS.streams[fildes] && FS.streams[fildes].isWrite) {
      return _truncate(FS.streams[fildes].path, length);
    } else if (FS.streams[fildes]) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  getcwd__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  getcwd: function(buf, size) {
    // char *getcwd(char *buf, size_t size);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getcwd.html
    if (size == 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return 0;
    } else if (size < FS.currentPath.length + 1) {
      ___setErrNo(ERRNO_CODES.ERANGE);
      return 0;
    } else {
      for (var i = 0; i < FS.currentPath.length; i++) {
        {{{ makeSetValue('buf', 'i', 'FS.currentPath.charCodeAt(i)', 'i8') }}}
      }
      {{{ makeSetValue('buf', 'i', '0', 'i8') }}}
      return buf;
    }
  },
  getwd__deps: ['getcwd'],
  getwd: function(path_name) {
    // char *getwd(char *path_name);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getwd.html
    return _getcwd(path_name, 4096);  // PATH_MAX.
  },
  isatty__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  isatty: function(fildes) {
    // int isatty(int fildes);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/isatty.html
    if (FS.streams[fildes]) {
      var object = FS.streams[fildes].object;
      if (object.isDevice && object.input && object.output) {
        // As far as we're concerned, a TTY is any device which supports both
        // input and output.
        return 0;
      } else {
        ___setErrNo(ERRNO_CODES.ENOTTY);
        return -1;
      }
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  lchown__deps: ['chown'],
  lchown: function(path, owner, group) {
    // int lchown(const char *path, uid_t owner, gid_t group);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/lchown.html
    return _chown(path, owner, group, true);
  },
  link__deps: ['__setErrNo', '$ERRNO_CODES'],
  link: function(path1, path2) {
    // int link(const char *path1, const char *path2);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/link.html
    // We don't support hard links.
    ___setErrNo(ERRNO_CODES.EMLINK);
    return -1;
  },
  lockf__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  lockf: function(fildes, func, size) {
    // int lockf(int fildes, int function, off_t size);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/lockf.html
    if (FS.streams[fildes]) {
      // Pretend whatever locking or unlocking operation succeeded. Locking does
      // not make much sense, since we have a single process/thread.
      return 0;
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  lseek__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  lseek: function(fildes, offset, whence) {
    // off_t lseek(int fildes, off_t offset, int whence);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/lseek.html
    if (FS.streams[fildes] && !FS.streams[fildes].isDevice) {
      var stream = FS.streams[fildes];
      var position = offset;
      if (whence === 1) {  // SEEK_CUR.
        position += stream.position;
      } else if (whence === 2) {  // SEEK_END.
        position += stream.object.contents.length;
      }
      if (position < 0) {
        ___setErrNo(ERRNO_CODES.EINVAL);
        return -1;
      } else {
        stream.ungotten = [];
        stream.position = position;
        return position;
      }
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  pipe__deps: ['__setErrNo', '$ERRNO_CODES'],
  pipe: function(fildes) {
    // int pipe(int fildes[2]);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/pipe.html
    // It is possible to implement this using two device streams, but pipes make
    // little sense in a single-threaded environment, so we do not support them.
    ___setErrNo(ERRNO_CODES.ENOSYS);
    return -1;
  },
  pread__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  pread: function(fildes, buf, nbyte, offset) {
    // ssize_t pread(int fildes, void *buf, size_t nbyte, off_t offset);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/read.html
    var stream = FS.streams[fildes];
    if (!stream || stream.object.isDevice) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    } else if (!stream.isRead) {
      ___setErrNo(ERRNO_CODES.EACCES);
      return -1;
    } else if (stream.object.isFolder) {
      ___setErrNo(ERRNO_CODES.EISDIR);
      return -1;
    } else if (nbyte < 0 || offset < 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    } else {
      var bytesRead = 0;
      while (stream.ungotten.length && nbyte > 0) {
        {{{ makeSetValue('buf++', '0', 'stream.ungotten.pop()', 'i8') }}}
        nbyte--;
        bytesRead++;
      }
      var contents = stream.object.contents;
      var size = Math.min(contents.length - offset, nbyte);
      for (var i = 0; i < size; i++) {
        {{{ makeSetValue('buf', 'i', 'contents[offset + i]', 'i8') }}}
        bytesRead++;
      }
      return bytesRead;
    }
  },
  read__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', 'pread'],
  read: function(fildes, buf, nbyte) {
    // ssize_t read(int fildes, void *buf, size_t nbyte);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/read.html
    var stream = FS.streams[fildes];
    if (!stream) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    } else if (!stream.isRead) {
      ___setErrNo(ERRNO_CODES.EACCES);
      return -1;
    } else if (nbyte < 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    } else {
      var bytesRead;
      if (stream.object.isDevice) {
        if (stream.object.input) {
          bytesRead = 0;
          while (stream.ungotten.length && nbyte > 0) {
            {{{ makeSetValue('buf++', '0', 'stream.ungotten.pop()', 'i8') }}}
            nbyte--;
            bytesRead++;
          }
          for (var i = 0; i < nbyte; i++) {
            try {
              var result = stream.object.input();
            } catch (e) {
              ___setErrNo(ERRNO_CODES.EIO);
              return -1;
            }
            if (result === null || result === undefined) break;
            bytesRead++;
            {{{ makeSetValue('buf', 'i', 'result', 'i8') }}}
          }
          return bytesRead;
        } else {
          ___setErrNo(ERRNO_CODES.ENXIO);
          return -1;
        }
      } else {
        var ungotSize = stream.ungotten.length;
        bytesRead = _pread(fildes, buf, nbyte, stream.position);
        if (bytesRead != -1) {
          stream.position += (stream.ungotten.length - ungotSize) + bytesRead;
        }
        return bytesRead;
      }
    }
  },
  sync: function() {
    // void sync(void);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/sync.html
    // All our writing is already synchronized. This is a no-op.
  },
  rmdir__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  rmdir: function(path) {
    // int rmdir(const char *path);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/rmdir.html
    path = FS.analyzePath(Pointer_stringify(path));
    if (!path.parentExists || !path.exists) {
      ___setErrNo(path.error);
      return -1;
    } else if (!path.object.write || path.isRoot) {
      ___setErrNo(ERRNO_CODES.EACCES);
      return -1;
    } else if (!path.object.isFolder) {
      ___setErrNo(ERRNO_CODES.ENOTDIR);
      return -1;
    } else {
      for (var i in path.object.contents) {
        ___setErrNo(ERRNO_CODES.ENOTEMPTY);
        return -1;
      }
      if (path.path == FS.currentPath) {
        ___setErrNo(ERRNO_CODES.EBUSY);
        return -1;
      } else {
        delete path.parentObject.contents[path.name];
        return 0;
      }
    }
  },
  unlink__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  unlink: function(path) {
    // int unlink(const char *path);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/unlink.html
    path = FS.analyzePath(Pointer_stringify(path));
    if (!path.parentExists || !path.exists) {
      ___setErrNo(path.error);
      return -1;
    } else if (path.object.isFolder) {
      ___setErrNo(ERRNO_CODES.EISDIR);
      return -1;
    } else if (!path.object.write) {
      ___setErrNo(ERRNO_CODES.EACCES);
      return -1;
    } else {
      delete path.parentObject.contents[path.name];
      return 0;
    }
  },
  ttyname__deps: ['ttyname_r'],
  ttyname: function(fildes) {
    // char *ttyname(int fildes);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/ttyname.html
    if (!_ttyname.ret) _ttyname.ret = _malloc(256);
    return _ttyname_r(fildes, _ttyname.ret, 256) ? 0 : _ttyname.ret;
  },
  ttyname_r__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  ttyname_r: function(fildes, name, namesize) {
    // int ttyname_r(int fildes, char *name, size_t namesize);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/ttyname.html
    var stream = FS.streams[fildes];
    if (!stream) {
      return ___setErrNo(ERRNO_CODES.EBADF);
    } else {
      var object = stream.object;
      if (!object.isDevice || !object.input || !object.output) {
        return ___setErrNo(ERRNO_CODES.ENOTTY);
      } else {
        var ret = stream.path;
        if (namesize < ret.length + 1) {
          return ___setErrNo(ERRNO_CODES.ERANGE);
        } else {
          for (var i = 0; i < ret.length; i++) {
            {{{ makeSetValue('name', 'i', 'ret.charCodeAt(i)', 'i8') }}}
          }
          {{{ makeSetValue('name', 'i', '0', 'i8') }}}
          return 0;
        }
      }
    }
  },
  symlink__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  symlink: function(path1, path2) {
    // int symlink(const char *path1, const char *path2);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/symlink.html
    var path = FS.analyzePath(Pointer_stringify(path2), true);
    if (!path.parentExists) {
      ___setErrNo(path.error);
      return -1;
    } else if (path.exists) {
      ___setErrNo(ERRNO_CODES.EEXIST);
      return -1;
    } else {
      FS.createLink(path.parentPath, path.name,
                    Pointer_stringify(path1), true, true);
      return 0;
    }
  },
  readlink__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  readlink: function(path, buf, bufsize) {
    // ssize_t readlink(const char *restrict path, char *restrict buf, size_t bufsize);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/readlink.html
    var target = FS.findObject(Pointer_stringify(path), true);
    if (target === null) return -1;
    if (target.link !== undefined) {
      var length = Math.min(bufsize - 1, target.link.length);
      for (var i = 0; i < length; i++) {
        {{{ makeSetValue('buf', 'i', 'target.link.charCodeAt(i)', 'i8') }}}
      }
      if (bufsize - 1 > length) {{{ makeSetValue('buf', 'i', '0', 'i8') }}}
      return i;
    } else {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    }
  },
  pwrite__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  pwrite: function(fildes, buf, nbyte, offset) {
    // ssize_t pwrite(int fildes, const void *buf, size_t nbyte, off_t offset);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/write.html
    var stream = FS.streams[fildes];
    if (!stream || stream.object.isDevice) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    } else if (!stream.isWrite) {
      ___setErrNo(ERRNO_CODES.EACCES);
      return -1;
    } else if (stream.object.isFolder) {
      ___setErrNo(ERRNO_CODES.EISDIR);
      return -1;
    } else if (nbyte < 0 || offset < 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    } else {
      var contents = stream.object.contents;
      while (contents.length < offset) contents.push(0);
      for (var i = 0; i < nbyte; i++) {
        contents[offset + i] = {{{ makeGetValue('buf', 'i', 'i8') }}};
      }
      stream.object.timestamp = new Date().getTime();
      return i;
    }
  },
  write__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', 'pwrite'],
  write: function(fildes, buf, nbyte) {
    // ssize_t write(int fildes, const void *buf, size_t nbyte);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/write.html
    var stream = FS.streams[fildes];
    if (!stream) {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    } else if (!stream.isWrite) {
      ___setErrNo(ERRNO_CODES.EACCES);
      return -1;
    } else if (nbyte < 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    } else {
      if (stream.object.isDevice) {
        if (stream.object.output) {
          for (var i = 0; i < nbyte; i++) {
            try {
              stream.object.output({{{ makeGetValue('buf', 'i', 'i8') }}});
            } catch (e) {
              ___setErrNo(ERRNO_CODES.EIO);
              return -1;
            }
          }
          stream.object.timestamp = new Date().getTime();
          return i;
        } else {
          ___setErrNo(ERRNO_CODES.ENXIO);
          return -1;
        }
      } else {
        var bytesWritten = _pwrite(fildes, buf, nbyte, stream.position);
        if (bytesWritten != -1) stream.position += bytesWritten;
        return bytesWritten;
      }
    }
  },
  alarm: function(seconds) {
    // unsigned alarm(unsigned seconds);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/alarm.html
    // We don't support signals, and there's no way to indicate failure, so just
    // fail silently.
    return 0;
  },
  ualarm: 'alarm',
  confstr__deps: ['__setErrNo', '$ERRNO_CODES'],
  confstr: function(name, buf, len) {
    // size_t confstr(int name, char *buf, size_t len);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/confstr.html
    var value;
    switch (name) {
      case 0:  // _CS_PATH.
        // TODO: Get from environment variable.
        value = '/';
        break;
      case 1:  // _CS_POSIX_V6_WIDTH_RESTRICTED_ENVS.
        // Mimicing glibc.
        value = 'POSIX_V6_ILP32_OFF32\nPOSIX_V6_ILP32_OFFBIG';
        break;
      case 2:  // _CS_GNU_LIBC_VERSION.
        // This JS implementation was tested against this glibc version.
        value = 'glibc 2.14';
        break;
      case 3:  // _CS_GNU_LIBPTHREAD_VERSION.
        // We don't support pthread.
        value = '';
        break;
      case 1118:  // _CS_POSIX_V6_ILP32_OFF32_LIBS.
      case 1122:  // _CS_POSIX_V6_ILP32_OFFBIG_LIBS.
      case 1124:  // _CS_POSIX_V6_LP64_OFF64_CFLAGS.
      case 1125:  // _CS_POSIX_V6_LP64_OFF64_LDFLAGS.
      case 1126:  // _CS_POSIX_V6_LP64_OFF64_LIBS.
      case 1128:  // _CS_POSIX_V6_LPBIG_OFFBIG_CFLAGS.
      case 1129:  // _CS_POSIX_V6_LPBIG_OFFBIG_LDFLAGS.
      case 1130:  // _CS_POSIX_V6_LPBIG_OFFBIG_LIBS.
        value = '';
        break;
      case 1116:  // _CS_POSIX_V6_ILP32_OFF32_CFLAGS.
      case 1117:  // _CS_POSIX_V6_ILP32_OFF32_LDFLAGS.
      case 1121:  // _CS_POSIX_V6_ILP32_OFFBIG_LDFLAGS.
        value = '-m32';
        break;
      case 1120:  // _CS_POSIX_V6_ILP32_OFFBIG_CFLAGS.
        value = '-m32 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64';
        break;
      default:
        ___setErrNo(ERRNO_CODES.EINVAL);
        return 0;
    }
    if (len == 0 || buf == 0) {
      return value.length + 1;
    } else {
      var length = Math.min(len, value.length);
      for (var i = 0; i < length; i++) {
        {{{ makeSetValue('buf', 'i', 'value.charCodeAt(i)', 'i8') }}}
      }
      if (len > length) {{{ makeSetValue('buf', 'i++', '0', 'i8') }}}
      return i;
    }
  },
  execl__deps: ['__setErrNo', '$ERRNO_CODES'],
  execl: function(/* ... */) {
    // int execl(const char *path, const char *arg0, ... /*, (char *)0 */);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/exec.html
    // We don't support executing external code.
    ___setErrNo(ERRNO_CODES.ENOEXEC);
    return -1;
  },
  execle: 'execl',
  execlp: 'execl',
  execv: 'execl',
  execve: 'execl',
  execvp: 'execl',
  _exit: function(status) {
    // void _exit(int status);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/exit.html
    __shutdownRuntime__();
    ABORT = true;
    throw 'exit(' + status + ') called, at ' + new Error().stack;
  },
  fork__deps: ['__setErrNo', '$ERRNO_CODES'],
  fork: function() {
    // pid_t fork(void);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fork.html
    // We don't support multiple processes.
    ___setErrNo(ERRNO_CODES.EAGAIN);
    return -1;
  },
  vfork: 'fork',
  getgid: function() {
    // gid_t getgid(void);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getgid.html
    // We have just one process/group/user, all with ID 0.
    return 0;
  },
  getegid: 'getgid',
  getuid: 'getgid',
  geteuid: 'getgid',
  getpgrp: 'getgid',
  getpid: 'getgid',
  getppid: 'getgid',
  getresuid: function(ruid, euid, suid) {
    // int getresuid(uid_t *ruid, uid_t *euid, uid_t *suid);
    // http://linux.die.net/man/2/getresuid
    // We have just one process/group/user, all with ID 0.
    {{{ makeSetValue('ruid', '0', '0', 'i32') }}}
    {{{ makeSetValue('euid', '0', '0', 'i32') }}}
    {{{ makeSetValue('suid', '0', '0', 'i32') }}}
    return 0;
  },
  getresgid: 'getresuid',
  getgroups__deps: ['__setErrNo', '$ERRNO_CODES'],
  getgroups: function(gidsetsize, grouplist) {
    // int getgroups(int gidsetsize, gid_t grouplist[]);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getgroups.html
    if (gidsetsize < 1) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    } else {
      {{{ makeSetValue('grouplist', '0', '0', 'i32') }}}
      return 1;
    }
  },
  // TODO: Implement initgroups, setgroups (grp.h).
  gethostid: function() {
    // long gethostid(void);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/gethostid.html
    return 42;
  },
  gethostname__deps: ['__setErrNo', '$ERRNO_CODES'],
  gethostname: function(name, namelen) {
    // int gethostname(char *name, size_t namelen);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/gethostname.html
    var host = 'emscripten';
    if (typeof window !== 'undefined' && window.location.host) {
      host = window.location.host;
    }
    var length = Math.min(namelen, host.length);
    for (var i = 0; i < length; i++) {
      {{{ makeSetValue('name', 'i', 'host.charCodeAt(i)', 'i8') }}}
    }
    if (namelen > length) {
      {{{ makeSetValue('name', 'i', '0', 'i8') }}}
      return 0;
    } else {
      ___setErrNo(ERRNO_CODES.ENAMETOOLONG);
      return -1;
    }
  },
  getlogin__deps: ['getlogin_r'],
  getlogin: function() {
    // char *getlogin(void);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getlogin.html
    if (!_getlogin.ret) _getlogin.ret = _malloc(8);
    return _getlogin_r(_getlogin.ret, 8) ? 0 : _getlogin.ret;
  },
  getlogin_r__deps: ['__setErrNo', '$ERRNO_CODES'],
  getlogin_r: function(name, namesize) {
    // int getlogin_r(char *name, size_t namesize);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getlogin.html
    var ret = 'root';
    if (namesize < ret.length + 1) {
      return ___setErrNo(ERRNO_CODES.ERANGE);
    } else {
      for (var i = 0; i < ret.length; i++) {
        {{{ makeSetValue('name', 'i', 'ret.charCodeAt(i)', 'i8') }}}
      }
      {{{ makeSetValue('name', 'i', '0', 'i8') }}}
      return 0;
    }
  },
  getopt: function(argc, argv, optstring) {
    // int getopt(int argc, char * const argv[], const char *optstring);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getopt.html
    // TODO: Implement (probably compile from C).
    return -1;
  },
  getpgid: function(pid) {
    // pid_t getpgid(pid_t pid);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getpgid.html
    // There can only be one process, and its group ID is 0.
    return 0;
  },
  getsid: 'getpgid',
  nice__deps: ['__setErrNo', '$ERRNO_CODES'],
  nice: function(incr) {
    // int nice(int incr);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/nice.html
    // Niceness makes no sense in a single-process environment.
    ___setErrNo(ERRNO_CODES.EPERM);
    return 0;
  },
  pause__deps: ['__setErrNo', '$ERRNO_CODES'],
  pause: function() {
    // int pause(void);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/pause.html
    // We don't support signals, so we return immediately.
    ___setErrNo(ERRNO_CODES.EINTR);
    return -1;
  },
  setgid__deps: ['__setErrNo', '$ERRNO_CODES'],
  setgid: function(gid) {
    // int setgid(gid_t gid);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/setgid.html
    // We have just one process/group/user, so it makes no sense to set IDs.
    ___setErrNo(ERRNO_CODES.EPERM);
    return -1;
  },
  setegid: 'setgid',
  setuid: 'setgid',
  seteuid: 'setgid',
  setsid: 'setgid',
  setpgrp: 'setgid',
  setpgid__deps: ['__setErrNo', '$ERRNO_CODES'],
  setpgid: function(pid, pgid) {
    // int setpgid(pid_t pid, pid_t pgid);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getpgid.html
    // We have just one process/group/user, so it makes no sense to set IDs.
    ___setErrNo(ERRNO_CODES.EPERM);
    return -1;
  },
  setregid: 'setpgid',
  setreuid: 'setpgid',
  // NOTE: These do not match the signatures, but they all use the same stub.
  setresuid: 'setpgid',
  setresgid: 'setpgid',
  sleep__deps: ['usleep'],
  sleep: function(seconds) {
    // unsigned sleep(unsigned seconds);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/sleep.html
    return _usleep(seconds * 1e6);
  },
  usleep: function(useconds) {
    // int usleep(useconds_t useconds);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/usleep.html
    // We're single-threaded, so use a busy loop. Super-ugly.
    var msec = useconds / 1000;
    var start = new Date().getTime();
    while (new Date().getTime() - start < msec);
    return 0;
  },
  swab: function(src, dest, nbytes) {
    // void swab(const void *restrict src, void *restrict dest, ssize_t nbytes);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/swab.html
    if (nbytes < 0) return;
    nbytes -= nbytes % 2;
    for (var i = 0; i < nbytes; i += 2) {
      var first = {{{ makeGetValue('src', 'i', 'i8') }}};
      var second = {{{ makeGetValue('src', 'i + 1', 'i8') }}};
      {{{ makeSetValue('dest', 'i', 'second', 'i8') }}}
      {{{ makeSetValue('dest', 'i + 1', 'first', 'i8') }}}
    }
  },
  tcgetpgrp: function(fildes) {
    // pid_t tcgetpgrp(int fildes);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/tcgetpgrp.html
    // Our only process always runs with group ID 0.
    return 0;
  },
  tcsetpgrp__deps: ['__setErrNo', '$ERRNO_CODES'],
  tcsetpgrp: function(fildes, pgid_id) {
    // int tcsetpgrp(int fildes, pid_t pgid_id);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/tcsetpgrp.html
    // We don't support multiple processes or groups with ID other than 0.
    ___setErrNo(ERRNO_CODES.EINVAL);
    return -1;
  },
  sysconf__deps: ['__setErrNo', '$ERRNO_CODES'],
  sysconf: function(name) {
    // long sysconf(int name);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/sysconf.html
    // WARNING: Except for PAGE_SIZE, this is generated by a C program using
    //          glibc. All the constants depend on values provided by glibc, and
    //          code compiled with other C libraries is not guaranteed to work.
    switch(name) {
      case 30: return PAGE_SIZE;   // _SC_PAGE_SIZE / _SC_PAGESIZE
      case 132:                    // _SC_ADVISORY_INFO
      case 133:                    // _SC_BARRIERS
      case 12:                     // _SC_ASYNCHRONOUS_IO
      case 137:                    // _SC_CLOCK_SELECTION
      case 138:                    // _SC_CPUTIME
      case 15:                     // _SC_FSYNC
      case 235:                    // _SC_IPV6
      case 16:                     // _SC_MAPPED_FILES
      case 17:                     // _SC_MEMLOCK
      case 18:                     // _SC_MEMLOCK_RANGE
      case 19:                     // _SC_MEMORY_PROTECTION
      case 20:                     // _SC_MESSAGE_PASSING
      case 149:                    // _SC_MONOTONIC_CLOCK
      case 13:                     // _SC_PRIORITIZED_IO
      case 10:                     // _SC_PRIORITY_SCHEDULING
      case 236:                    // _SC_RAW_SOCKETS
      case 153:                    // _SC_READER_WRITER_LOCKS
      case 9:                      // _SC_REALTIME_SIGNALS
      case 21:                     // _SC_SEMAPHORES
      case 22:                     // _SC_SHARED_MEMORY_OBJECTS
      case 159:                    // _SC_SPAWN
      case 154:                    // _SC_SPIN_LOCKS
      case 14:                     // _SC_SYNCHRONIZED_IO
      case 77:                     // _SC_THREAD_ATTR_STACKADDR
      case 78:                     // _SC_THREAD_ATTR_STACKSIZE
      case 139:                    // _SC_THREAD_CPUTIME
      case 80:                     // _SC_THREAD_PRIO_INHERIT
      case 81:                     // _SC_THREAD_PRIO_PROTECT
      case 79:                     // _SC_THREAD_PRIORITY_SCHEDULING
      case 82:                     // _SC_THREAD_PROCESS_SHARED
      case 68:                     // _SC_THREAD_SAFE_FUNCTIONS
      case 67:                     // _SC_THREADS
      case 164:                    // _SC_TIMEOUTS
      case 11:                     // _SC_TIMERS
      case 29:                     // _SC_VERSION
      case 47:                     // _SC_2_C_BIND
      case 48:                     // _SC_2_C_DEV
      case 95:                     // _SC_2_CHAR_TERM
      case 52:                     // _SC_2_LOCALEDEF
      case 51:                     // _SC_2_SW_DEV
      case 46:                     // _SC_2_VERSION
        return 200809;
      case 27:                     // _SC_MQ_OPEN_MAX
      case 246:                    // _SC_XOPEN_STREAMS
      case 127:                    // _SC_XBS5_LP64_OFF64
      case 128:                    // _SC_XBS5_LPBIG_OFFBIG
      case 23:                     // _SC_AIO_LISTIO_MAX
      case 24:                     // _SC_AIO_MAX
      case 160:                    // _SC_SPORADIC_SERVER
      case 161:                    // _SC_THREAD_SPORADIC_SERVER
      case 181:                    // _SC_TRACE
      case 182:                    // _SC_TRACE_EVENT_FILTER
      case 242:                    // _SC_TRACE_EVENT_NAME_MAX
      case 183:                    // _SC_TRACE_INHERIT
      case 184:                    // _SC_TRACE_LOG
      case 243:                    // _SC_TRACE_NAME_MAX
      case 244:                    // _SC_TRACE_SYS_MAX
      case 245:                    // _SC_TRACE_USER_EVENT_MAX
      case 165:                    // _SC_TYPED_MEMORY_OBJECTS
      case 178:                    // _SC_V6_LP64_OFF64
      case 179:                    // _SC_V6_LPBIG_OFFBIG
      case 49:                     // _SC_2_FORT_DEV
      case 50:                     // _SC_2_FORT_RUN
      case 168:                    // _SC_2_PBS
      case 169:                    // _SC_2_PBS_ACCOUNTING
      case 175:                    // _SC_2_PBS_CHECKPOINT
      case 170:                    // _SC_2_PBS_LOCATE
      case 171:                    // _SC_2_PBS_MESSAGE
      case 172:                    // _SC_2_PBS_TRACK
      case 97:                     // _SC_2_UPE
      case 76:                     // _SC_THREAD_THREADS_MAX
      case 32:                     // _SC_SEM_NSEMS_MAX
      case 173:                    // _SC_SYMLOOP_MAX
      case 35:                     // _SC_TIMER_MAX
        return -1;
      case 176:                    // _SC_V6_ILP32_OFF32
      case 177:                    // _SC_V6_ILP32_OFFBIG
      case 7:                      // _SC_JOB_CONTROL
      case 155:                    // _SC_REGEXP
      case 8:                      // _SC_SAVED_IDS
      case 157:                    // _SC_SHELL
      case 125:                    // _SC_XBS5_ILP32_OFF32
      case 126:                    // _SC_XBS5_ILP32_OFFBIG
      case 92:                     // _SC_XOPEN_CRYPT
      case 93:                     // _SC_XOPEN_ENH_I18N
      case 129:                    // _SC_XOPEN_LEGACY
      case 130:                    // _SC_XOPEN_REALTIME
      case 131:                    // _SC_XOPEN_REALTIME_THREADS
      case 94:                     // _SC_XOPEN_SHM
      case 91:                     // _SC_XOPEN_UNIX
        return 1;
      case 74:                     // _SC_THREAD_KEYS_MAX
      case 60:                     // _SC_IOV_MAX
      case 69:                     // _SC_GETGR_R_SIZE_MAX
      case 70:                     // _SC_GETPW_R_SIZE_MAX
      case 4:                      // _SC_OPEN_MAX
        return 1024;
      case 31:                     // _SC_RTSIG_MAX
      case 42:                     // _SC_EXPR_NEST_MAX
      case 72:                     // _SC_TTY_NAME_MAX
        return 32;
      case 87:                     // _SC_ATEXIT_MAX
      case 26:                     // _SC_DELAYTIMER_MAX
      case 33:                     // _SC_SEM_VALUE_MAX
        return 2147483647;
      case 34:                     // _SC_SIGQUEUE_MAX
      case 1:                      // _SC_CHILD_MAX
        return 47839;
      case 38:                     // _SC_BC_SCALE_MAX
      case 36:                     // _SC_BC_BASE_MAX
        return 99;
      case 43:                     // _SC_LINE_MAX
      case 37:                     // _SC_BC_DIM_MAX
        return 2048;
      case 0: return 2097152;      // _SC_ARG_MAX
      case 3: return 65536;        // _SC_NGROUPS_MAX
      case 28: return 32768;       // _SC_MQ_PRIO_MAX
      case 44: return 32767;       // _SC_RE_DUP_MAX
      case 75: return 16384;       // _SC_THREAD_STACK_MIN
      case 39: return 1000;        // _SC_BC_STRING_MAX
      case 89: return 700;         // _SC_XOPEN_VERSION
      case 71: return 256;         // _SC_LOGIN_NAME_MAX
      case 40: return 255;         // _SC_COLL_WEIGHTS_MAX
      case 2: return 100;          // _SC_CLK_TCK
      case 180: return 64;         // _SC_HOST_NAME_MAX
      case 25: return 20;          // _SC_AIO_PRIO_DELTA_MAX
      case 5: return 16;           // _SC_STREAM_MAX
      case 6: return 6;            // _SC_TZNAME_MAX
      case 73: return 4;           // _SC_THREAD_DESTRUCTOR_ITERATIONS
    }
    ___setErrNo(ERRNO_CODES.EINVAL);
    return -1;
  },
  sbrk: function(bytes) {
    // Implement a Linux-like 'memory area' for our 'process'.
    // Changes the size of the memory area by |bytes|; returns the
    // address of the previous top ('break') of the memory area

    // We need to make sure no one else allocates unfreeable memory!
    // We must control this entirely. So we don't even need to do
    // unfreeable allocations - the HEAP is ours, from STATICTOP up.
    // TODO: We could in theory slice off the top of the HEAP when
    //       sbrk gets a negative increment in |bytes|...
    var self = _sbrk;
    if (!self.STATICTOP) {
      STATICTOP = alignMemoryPage(STATICTOP);
      self.STATICTOP = STATICTOP;
      self.DATASIZE = 0;
    } else {
      assert(self.STATICTOP == STATICTOP, "No one should touch the heap!");
    }
    var ret = STATICTOP + self.DATASIZE;
    self.DATASIZE += alignMemoryPage(bytes);
    return ret;  // Previous break location.
  },
  __01open64_: 'open',
  __01lseek64_: 'lseek',
  __01ftruncate64_: 'ftruncate',
  // TODO: Check if any other aliases are needed.

  // ==========================================================================
  // stdio.h
  // ==========================================================================

  // TODO: Document.
  _scanString: function(format, get, unget, args) {
    // Supports %x, %4x, %d.%d, %s.
    // TODO: Support all format specifiers.
    format = Pointer_stringify(format);
    var formatIndex = 0;
    var argsi = 0;
    var fields = 0;
    for (var formatIndex = 0; formatIndex < format.length; formatIndex++) {
      var next = get();
      if (next <= 0) return fields;  // End of input.
      if (format[formatIndex] === '%') {
        formatIndex++;
        var maxSpecifierStart = formatIndex;
        while (format[formatIndex].charCodeAt(0) >= '0'.charCodeAt(0) &&
               format[formatIndex].charCodeAt(0) <= '9'.charCodeAt(0)) {
          formatIndex++;
        }
        var max_;
        if (formatIndex != maxSpecifierStart) {
          max_ = parseInt(format.slice(maxSpecifierStart, formatIndex), 10);
        }
        // TODO: Handle type size modifier.
        var type = format[formatIndex];
        formatIndex++;
        var curr = 0;
        var buffer = [];
        while ((curr < max_ || isNaN(max_)) && next > 0) {
          if ((type === 'd' && next >= '0'.charCodeAt(0) && next <= '9'.charCodeAt(0)) ||
              (type === 'x' && (next >= '0'.charCodeAt(0) && next <= '9'.charCodeAt(0) ||
                                next >= 'a'.charCodeAt(0) && next <= 'f'.charCodeAt(0) ||
                                next >= 'A'.charCodeAt(0) && next <= 'F'.charCodeAt(0))) ||
              (type === 's')) {
            buffer.push(String.fromCharCode(next));
            next = get();
          } else {
            break;
          }
        }
        if (buffer.length === 0) return 0;  // Failure.
        var text = buffer.join('');
        switch (type) {
          case 'd':
            {{{ makeSetValue('args.shift()', '0', 'parseInt(text, 10)', 'i32') }}}
            break;
          case 'x':
            {{{ makeSetValue('args.shift()', '0', 'parseInt(text, 16)', 'i32') }}}
            break;
          case 's':
            var array = intArrayFromString(text);
            var buf = args.shift();
            for (var j = 0; j < array.length; j++) {
              {{{ makeSetValue('buf', 'j', 'array[j]', 'i8') }}}
            }
            break;
        }
        fields++;
      } else {
        // Not a specifier.
        if (format[formatIndex].charCodeAt(0) !== next) {
          unget(next);
          return fields;
        }
      }
    }
    return fields;
  },
  // Performs prtinf-style formatting.
  //   isVarArgs: Whether the arguments are passed in varargs style, i.e. the
  //     third parameter is an address of the start of the argument list.
  //   format: A pointer to the format string.
  // Returns the resulting string string as a character array.
  _formatString: function(isVarArgs, format/*, ...*/) {
    var textIndex = format;
    var argIndex = 0;
    var getNextArg;
    if (isVarArgs) {
      var varArgStart = arguments[2];
      getNextArg = function(type) {
        var ret;
        if (type === 'double') {
          ret = {{{ makeGetValue('varArgStart', 'argIndex', 'double') }}};
        } else if (type === 'float') {
          ret = {{{ makeGetValue('varArgStart', 'argIndex', 'float') }}};
        } else if (type === 'i64') {
          ret = {{{ makeGetValue('varArgStart', 'argIndex', 'i64') }}};
        } else if (type === 'i32') {
          ret = {{{ makeGetValue('varArgStart', 'argIndex', 'i32') }}};
        } else if (type === 'i16') {
          ret = {{{ makeGetValue('varArgStart', 'argIndex', 'i16') }}};
        } else if (type === 'i8') {
          ret = {{{ makeGetValue('varArgStart', 'argIndex', 'i8') }}};
        } else if (type[type.length - 1] === '*') {
          ret = {{{ makeGetValue('varArgStart', 'argIndex', 'void*') }}};
        } else {
          throw new Error('Unknown formatString argument type: ' + type);
        }
        argIndex += Runtime.getNativeFieldSize(type);
        return Number(ret);
      };
    } else {
      var args = arguments;
      getNextArg = function() {
        return Number(args[2 + argIndex++]);
      };
    }

    var ret = [];
    var curr, next, currArg;
    while(1) {
      var startTextIndex = textIndex;
      curr = {{{ makeGetValue(0, 'textIndex', 'i8') }}};
      if (curr === 0) break;
      next = {{{ makeGetValue(0, 'textIndex+1', 'i8') }}};
      if (curr == '%'.charCodeAt(0)) {
        // Handle flags.
        var flagAlwaysSigned = false;
        var flagLeftAlign = false;
        var flagAlternative = false;
        var flagZeroPad = false;
        flagsLoop: while (1) {
          switch (next) {
            case '+'.charCodeAt(0):
              flagAlwaysSigned = true;
              break;
            case '-'.charCodeAt(0):
              flagLeftAlign = true;
              break;
            case '#'.charCodeAt(0):
              flagAlternative = true;
              break;
            case '0'.charCodeAt(0):
              if (flagZeroPad) {
                break flagsLoop;
              } else {
                flagZeroPad = true;
                break;
              }
            default:
              break flagsLoop;
          }
          textIndex++;
          next = {{{ makeGetValue(0, 'textIndex+1', 'i8') }}};
        }

        // Handle width.
        var width = 0;
        if (next == '*'.charCodeAt(0)) {
          width = getNextArg('i32');
          textIndex++;
          next = {{{ makeGetValue(0, 'textIndex+1', 'i8') }}};
        } else {
          while (next >= '0'.charCodeAt(0) && next <= '9'.charCodeAt(0)) {
            width = width * 10 + (next - '0'.charCodeAt(0));
            textIndex++;
            next = {{{ makeGetValue(0, 'textIndex+1', 'i8') }}};
          }
        }

        // Handle precision.
        var precisionSet = false;
        if (next == '.'.charCodeAt(0)) {
          var precision = 0;
          precisionSet = true;
          textIndex++;
          next = {{{ makeGetValue(0, 'textIndex+1', 'i8') }}};
          if (next == '*'.charCodeAt(0)) {
            precision = getNextArg('i32');
            textIndex++;
          } else {
            while(1) {
              var precisionChr = {{{ makeGetValue(0, 'textIndex+1', 'i8') }}};
              if (precisionChr < '0'.charCodeAt(0) ||
                  precisionChr > '9'.charCodeAt(0)) break;
              precision = precision * 10 + (precisionChr - '0'.charCodeAt(0));
              textIndex++;
            }
          }
          next = {{{ makeGetValue(0, 'textIndex+1', 'i8') }}};
        } else {
          var precision = 6; // Standard default.
        }

        // Handle integer sizes. WARNING: These assume a 32-bit architecture!
        var argSize;
        switch (String.fromCharCode(next)) {
          case 'h':
            var nextNext = {{{ makeGetValue(0, 'textIndex+2', 'i8') }}};
            if (nextNext == 'h'.charCodeAt(0)) {
              textIndex++;
              argSize = 1; // char
            } else {
              argSize = 2; // short
            }
            break;
          case 'l':
            var nextNext = {{{ makeGetValue(0, 'textIndex+2', 'i8') }}};
            if (nextNext == 'l'.charCodeAt(0)) {
              textIndex++;
              argSize = 8; // long long
            } else {
              argSize = 4; // long
            }
            break;
          case 'L': // long long
          case 'q': // int64_t
          case 'j': // intmax_t
            argSize = 8;
            break;
          case 'z': // size_t
          case 't': // ptrdiff_t
          case 'I': // signed ptrdiff_t or unsigned size_t
            argSize = 4;
            break;
          default:
            argSize = undefined;
        }
        if (argSize !== undefined) textIndex++;
        next = {{{ makeGetValue(0, 'textIndex+1', 'i8') }}};

        // Handle type specifier.
        if (['d', 'i', 'u', 'o', 'x', 'X', 'p'].indexOf(String.fromCharCode(next)) != -1) {
          // Integer.
          var signed = next == 'd'.charCodeAt(0) || next == 'i'.charCodeAt(0);
          argSize = argSize || 4;
          var currArg = getNextArg('i' + (argSize * 8));
          // Truncate to requested size.
          if (argSize <= 4) {
            var limit = Math.pow(256, argSize) - 1;
            currArg = (signed ? reSign : unSign)(currArg & limit, argSize * 8);
          }
          // Format the number.
          var currAbsArg = Math.abs(currArg);
          var argText;
          var prefix = '';
          if (next == 'd'.charCodeAt(0) || next == 'i'.charCodeAt(0)) {
            argText = currAbsArg.toString(10);
          } else if (next == 'u'.charCodeAt(0)) {
            argText = unSign(currArg, 8 * argSize).toString(10);
            currArg = Math.abs(currArg);
          } else if (next == 'o'.charCodeAt(0)) {
            argText = (flagAlternative ? '0' : '') + currAbsArg.toString(8);
          } else if (next == 'x'.charCodeAt(0) || next == 'X'.charCodeAt(0)) {
            prefix = flagAlternative ? '0x' : '';
            if (currArg < 0) {
              // Represent negative numbers in hex as 2's complement.
              currArg = -currArg;
              argText = (currAbsArg - 1).toString(16);
              var buffer = [];
              for (var i = 0; i < argText.length; i++) {
                buffer.push((0xF - parseInt(argText[i], 16)).toString(16));
              }
              argText = buffer.join('');
              while (argText.length < argSize * 2) argText = 'f' + argText;
            } else {
              argText = currAbsArg.toString(16);
            }
            if (next == 'X'.charCodeAt(0)) {
              prefix = prefix.toUpperCase();
              argText = argText.toUpperCase();
            }
          } else if (next == 'p'.charCodeAt(0)) {
            if (currAbsArg === 0) {
              argText = '(nil)';
            } else {
              prefix = '0x';
              argText = currAbsArg.toString(16);
            }
          }
          if (precisionSet) {
            while (argText.length < precision) {
              argText = '0' + argText;
            }
          }

          // Add sign.
          if (currArg < 0) {
            prefix = '-' + prefix;
          } else if (flagAlwaysSigned) {
            prefix = '+' + prefix;
          }

          // Add padding.
          while (prefix.length + argText.length < width) {
            if (flagLeftAlign) {
              argText += ' ';
            } else {
              if (flagZeroPad) {
                argText = '0' + argText;
              } else {
                prefix = ' ' + prefix;
              }
            }
          }

          // Insert the result into the buffer.
          argText = prefix + argText;
          argText.split('').forEach(function(chr) {
            ret.push(chr.charCodeAt(0));
          });
        } else if (['f', 'F', 'e', 'E', 'g', 'G'].indexOf(String.fromCharCode(next)) != -1) {
          // Float.
          var currArg = getNextArg(argSize === 4 ? 'float' : 'double');
          var argText;

          if (isNaN(currArg)) {
            argText = 'nan';
            flagZeroPad = false;
          } else if (!isFinite(currArg)) {
            argText = (currArg < 0 ? '-' : '') + 'inf';
            flagZeroPad = false;
          } else {
            var isGeneral = false;
            var effectivePrecision = Math.min(precision, 20);

            // Convert g/G to f/F or e/E, as per:
            // http://pubs.opengroup.org/onlinepubs/9699919799/functions/printf.html
            if (next == 'g'.charCodeAt(0) || next == 'G'.charCodeAt(0)) {
              isGeneral = true;
              precision = precision || 1;
              var exponent = parseInt(currArg.toExponential(effectivePrecision).split('e')[1], 10);
              if (precision > exponent && exponent >= -4) {
                next = ((next == 'g'.charCodeAt(0)) ? 'f' : 'F').charCodeAt(0);
                precision -= exponent + 1;
              } else {
                next = ((next == 'g'.charCodeAt(0)) ? 'e' : 'E').charCodeAt(0);
                precision--;
              }
              effectivePrecision = Math.min(precision, 20);
            }

            if (next == 'e'.charCodeAt(0) || next == 'E'.charCodeAt(0)) {
              argText = currArg.toExponential(effectivePrecision);
              // Make sure the exponent has at least 2 digits.
              if (/[eE][-+]\d$/.test(argText)) {
                argText = argText.slice(0, -1) + '0' + argText.slice(-1);
              }
            } else if (next == 'f'.charCodeAt(0) || next == 'F'.charCodeAt(0)) {
              argText = currArg.toFixed(effectivePrecision);
            }

            var parts = argText.split('e');
            if (isGeneral && !flagAlternative) {
              // Discard trailing zeros and periods.
              while (parts[0].length > 1 && parts[0].indexOf('.') != -1 &&
                     (parts[0].slice(-1) == '0' || parts[0].slice(-1) == '.')) {
                parts[0] = parts[0].slice(0, -1);
              }
            } else {
              // Make sure we have a period in alternative mode.
              if (flagAlternative && argText.indexOf('.') == -1) parts[0] += '.';
              // Zero pad until required precision.
              while (precision > effectivePrecision++) parts[0] += '0';
            }
            argText = parts[0] + (parts.length > 1 ? 'e' + parts[1] : '');

            // Capitalize 'E' if needed.
            if (next == 'E'.charCodeAt(0)) argText = argText.toUpperCase();

            // Add sign.
            if (flagAlwaysSigned && currArg >= 0) {
              argText = '+' + argText;
            }
          }

          // Add padding.
          while (argText.length < width) {
            if (flagLeftAlign) {
              argText += ' ';
            } else {
              if (flagZeroPad && (argText[0] == '-' || argText[0] == '+')) {
                argText = argText[0] + '0' + argText.slice(1);
              } else {
                argText = (flagZeroPad ? '0' : ' ') + argText;
              }
            }
          }

          // Adjust case.
          if (next < 'a'.charCodeAt(0)) argText = argText.toUpperCase();

          // Insert the result into the buffer.
          argText.split('').forEach(function(chr) {
            ret.push(chr.charCodeAt(0));
          });
        } else if (next == 's'.charCodeAt(0)) {
          // String.
          var arg = getNextArg('i8*');
          var copiedString;
          if (arg) {
            copiedString = String_copy(arg);
            if (precisionSet && copiedString.length > precision) {
              copiedString = copiedString.slice(0, precision);
            }
          } else {
            copiedString = intArrayFromString('(null)', true);
          }
          if (!flagLeftAlign) {
            while (copiedString.length < width--) {
              ret.push(' '.charCodeAt(0));
            }
          }
          ret = ret.concat(copiedString);
          if (flagLeftAlign) {
            while (copiedString.length < width--) {
              ret.push(' '.charCodeAt(0));
            }
          }
        } else if (next == 'c'.charCodeAt(0)) {
          // Character.
          if (flagLeftAlign) ret.push(getNextArg('i8'));
          while (--width > 0) {
            ret.push(' '.charCodeAt(0));
          }
          if (!flagLeftAlign) ret.push(getNextArg('i8'));
        } else if (next == 'n'.charCodeAt(0)) {
          // Write the length written so far to the next parameter.
          var ptr = getNextArg('i32*');
          {{{ makeSetValue('ptr', '0', 'ret.length', 'i32') }}}
        } else if (next == '%'.charCodeAt(0)) {
          // Literal percent sign.
          ret.push(curr);
        } else {
          // Unknown specifiers remain untouched.
          for (var i = startTextIndex; i < textIndex + 2; i++) {
            ret.push({{{ makeGetValue(0, 'i', 'i8') }}});
          }
        }
        textIndex += 2;
        // TODO: Support a/A (hex float) and m (last error) specifiers.
        // TODO: Support %1${specifier} for arg selection.
      } else {
        ret.push(curr);
        textIndex += 1;
      }
    }
    return ret;
  },
  // NOTE: Invalid stream pointers passed to these functions would cause a crash
  //       in native code. We, on the other hand, just ignore them, since it's
  //       easier.
  clearerr__deps: ['$FS'],
  clearerr: function(stream) {
    // void clearerr(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/clearerr.html
    if (stream in FS.streams) FS.streams[stream].error = false;
  },
  fclose__deps: ['close', 'fsync'],
  fclose: function(stream) {
    // int fclose(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fclose.html
    _fsync(stream);
    return _close(stream);
  },
  fdopen__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  fdopen: function(fildes, mode) {
    // FILE *fdopen(int fildes, const char *mode);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fdopen.html
    if (fildes in FS.streams) {
      var stream = FS.streams[fildes];
      mode = Pointer_stringify(mode);
      if ((mode.indexOf('w') != -1 && !stream.isWrite) ||
          (mode.indexOf('r') != -1 && !stream.isRead) ||
          (mode.indexOf('a') != -1 && !stream.isAppend) ||
          (mode.indexOf('+') != -1 && (!stream.isRead || !stream.isWrite))) {
        ___setErrNo(ERRNO_CODES.EINVAL);
        return 0;
      } else {
        stream.error = false;
        stream.eof = false;
        return fildes;
      }
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return 0;
    }
  },
  feof__deps: ['$FS'],
  feof: function(stream) {
    // int feof(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/feof.html
    return Number(stream in FS.streams && FS.streams[stream].eof);
  },
  ferror__deps: ['$FS'],
  ferror: function(stream) {
    // int ferror(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/ferror.html
    return Number(stream in FS.streams && FS.streams[stream].error);
  },
  fflush__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  fflush: function(stream) {
    // int fflush(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fflush.html
    var flush = function(filedes) {
      // Right now we write all data directly, except for output devices.
      if (filedes in FS.streams && FS.streams[filedes].object.output) {
        FS.streams[filedes].object.output(null);
      }
    };
    try {
      if (stream === 0) {
        for (var i in FS.streams) flush(i);
      } else {
        flush(stream);
      }
      return 0;
    } catch (e) {
      ___setErrNo(ERRNO_CODES.EIO);
      return -1;
    }
  },
  fgetc__deps: ['$FS', 'read'],
  fgetc: function(stream) {
    // int fgetc(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fgetc.html
    if (!(stream in FS.streams)) return -1;
    if (!_fgetc.buffer) _fgetc.buffer = _malloc(1);
    var streamObj = FS.streams[stream];
    if (streamObj.eof || streamObj.error) return -1;
    var ret = _read(stream, _fgetc.buffer, 1);
    if (ret == 0) {
      streamObj.eof = true;
      return -1;
    } else if (ret == -1) {
      streamObj.error = true;
      return -1;
    } else {
      return {{{ makeGetValue('_fgetc.buffer', '0', 'i8') }}};
    }
  },
  getc: 'fgetc',
  getc_unlocked: 'fgetc',
  getchar__deps: ['fgetc', 'stdin'],
  getchar: function() {
    // int getchar(void);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/getchar.html
    return _fgetc({{{ makeGetValue('_stdin', '0', 'void*') }}});
  },
  fgetpos__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  fgetpos: function(stream, pos) {
    // int fgetpos(FILE *restrict stream, fpos_t *restrict pos);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fgetpos.html
    if (stream in FS.streams) {
      stream = FS.streams[stream];
      if (stream.object.isDevice) {
        ___setErrNo(ERRNO_CODES.ESPIPE);
        return -1;
      } else {
        {{{ makeSetValue('pos', '0', 'stream.position', 'i32') }}}
        var state = (stream.eof ? 1 : 0) + (stream.error ? 2 : 0);
        {{{ makeSetValue('pos', Runtime.getNativeTypeSize('i32'), 'state', 'i32') }}}
        return 0;
      }
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  fgets__deps: ['fgetc'],
  fgets: function(s, n, stream) {
    // char *fgets(char *restrict s, int n, FILE *restrict stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fgets.html
    if (!(stream in FS.streams)) return 0;
    var streamObj = FS.streams[stream];
    if (streamObj.error || streamObj.eof) return 0;
    for (var i = 0; i < n - 1; i++) {
      var byte_ = _fgetc(stream);
      if (byte_ == -1) {
        if (streamObj.error) return 0;
        else if (streamObj.eof) break;
      } else if (byte_ == '\n'.charCodeAt(0)) {
        break;
      }
      {{{ makeSetValue('s', 'i', 'byte_', 'i8') }}}
    }
    {{{ makeSetValue('s', 'i', '0', 'i8') }}}
    return s;
  },
  gets__deps: ['fgets'],
  gets: function(s) {
    // char *gets(char *s);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/gets.html
    return _fgets(s, 1e6, {{{ makeGetValue('_stdin', '0', 'void*') }}});
  },
  fileno: function(stream) {
    // int fileno(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fileno.html
    // We use file descriptor numbers and FILE* streams interchangeably.
    return stream;
  },
  ftrylockfile: function() {
    // int ftrylockfile(FILE *file);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/flockfile.html
    // Locking is useless in a single-threaded environment. Pretend to succeed.
    return 0;
  },
  flockfile: 'ftrylockfile',
  funlockfile: 'ftrylockfile',
  fopen__deps: ['$FS', '__setErrNo', '$ERRNO_CODES', 'open'],
  fopen: function(filename, mode) {
    // FILE *fopen(const char *restrict filename, const char *restrict mode);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fopen.html
    var flags;
    mode = Pointer_stringify(mode);
    if (mode[0] == 'r') {
      if (mode.indexOf('+') != -1) {
        flags = 0x2;  // O_RDWR
      } else {
        flags = 0x0;  // O_RDONLY
      }
    } else if (mode[0] == 'w') {
      if (mode.indexOf('+') != -1) {
        flags = 0x2;  // O_RDWR
      } else {
        flags = 0x1;  // O_WRONLY
      }
      flags |= 0x40;  // O_CREAT
      flags |= 0x200;  // O_TRUNC
    } else if (mode[0] == 'a') {
      if (mode.indexOf('+') != -1) {
        flags = 0x2;  // O_RDWR
      } else {
        flags = 0x1;  // O_WRONLY
      }
      flags |= 0x40;  // O_CREAT
      flags |= 0x400;  // O_APPEND
    } else {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return 0;
    }
    var ret = _open(filename, flags, 0x1FF);  // All creation permissions.
    return (ret == -1) ? 0 : ret;
  },
  fputc__deps: ['write'],
  fputc: function(c, stream) {
    // int fputc(int c, FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fputc.html
    if (!_fputc.buffer) _fputc.buffer = _malloc(1);
    var chr = unSign(c & 0xFF);
    {{{ makeSetValue('_fputc.buffer', '0', 'chr', 'i8') }}}
    var ret = _write(stream, _fputc.buffer, 1);
    if (ret == -1) {
      if (stream in FS.streams) FS.streams[stream].error = true;
      return -1;
    } else {
      return chr;
    }
  },
  putc: 'fputc',
  putc_unlocked: 'fputc',
  putchar__deps: ['fputc', 'stdout'],
  putchar: function(c) {
    // int putchar(int c);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/putchar.html
    return _fputc(c, {{{ makeGetValue('_stdout', '0', 'void*') }}});
  },
  putchar_unlocked: 'putchar',
  fputs__deps: ['write', 'strlen'],
  fputs: function(s, stream) {
    // int fputs(const char *restrict s, FILE *restrict stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fputs.html
    return _write(stream, s, _strlen(s));
  },
  puts__deps: ['fputs', 'fputc', 'stdout'],
  puts: function(s) {
    // int puts(const char *s);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/puts.html
    // NOTE: puts() always writes an extra newline.
    var stdout = {{{ makeGetValue('_stdout', '0', 'void*') }}};
    var ret = _fputs(s, stdout);
    if (ret < 0) {
      return ret;
    } else {
      var newlineRet = _fputc('\n'.charCodeAt(0), stdout);
      return (newlineRet < 0) ? -1 : ret + 1;
    }
  },
  fread__deps: ['$FS', 'read'],
  fread: function(ptr, size, nitems, stream) {
    // size_t fread(void *restrict ptr, size_t size, size_t nitems, FILE *restrict stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fread.html
    var bytesToRead = nitems * size;
    if (bytesToRead == 0) return 0;
    var bytesRead = _read(stream, ptr, bytesToRead);
    var streamObj = FS.streams[stream];
    if (bytesRead == -1) {
      if (streamObj) streamObj.error = true;
      return -1;
    } else {
      if (bytesRead < bytesToRead) streamObj.eof = true;
      return Math.floor(bytesRead / size);
    }
  },
  freopen__deps: ['$FS', 'fclose', 'fopen', '__setErrNo', '$ERRNO_CODES'],
  freopen: function(filename, mode, stream) {
    // FILE *freopen(const char *restrict filename, const char *restrict mode, FILE *restrict stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/freopen.html
    if (!filename) {
      if (!(stream in FS.streams)) {
        ___setErrNo(ERRNO_CODES.EBADF);
        return 0;
      }
      if (_freopen.buffer) _free(_freopen.buffer);
      filename = intArrayFromString(FS.streams[stream].path);
      filename = allocate(filename, 'i8', ALLOC_NORMAL);
    }
    _fclose(stream);
    return _fopen(filename, mode);
  },
  fseek__deps: ['$FS', 'lseek'],
  fseek: function(stream, offset, whence) {
    // int fseek(FILE *stream, long offset, int whence);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fseek.html
    var ret = _lseek(stream, offset, whence);
    if (ret == -1) {
      return -1;
    } else {
      FS.streams[stream].eof = false;
      return 0;
    }
  },
  fseeko: 'fseek',
  fsetpos__deps: ['$FS', 'lseek', '__setErrNo', '$ERRNO_CODES'],
  fsetpos: function(stream, pos) {
    // int fsetpos(FILE *stream, const fpos_t *pos);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fsetpos.html
    if (stream in FS.streams) {
      if (FS.streams[stream].object.isDevice) {
        ___setErrNo(ERRNO_CODES.EPIPE);
        return -1;
      } else {
        FS.streams[stream].position = {{{ makeGetValue('pos', '0', 'i32') }}};
        var state = {{{ makeGetValue('pos', Runtime.getNativeTypeSize('i32'), 'i32') }}};
        FS.streams[stream].eof = Boolean(state & 1);
        FS.streams[stream].error = Boolean(state & 2);
        return 0;
      }
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  ftell__deps: ['$FS', '__setErrNo', '$ERRNO_CODES'],
  ftell: function(stream) {
    // long ftell(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/ftell.html
    if (stream in FS.streams) {
      stream = FS.streams[stream];
      if (stream.object.isDevice) {
        ___setErrNo(ERRNO_CODES.ESPIPE);
        return -1;
      } else {
        return stream.position;
      }
    } else {
      ___setErrNo(ERRNO_CODES.EBADF);
      return -1;
    }
  },
  ftello: 'ftell',
  fwrite__deps: ['$FS', 'write'],
  fwrite: function(ptr, size, nitems, stream) {
    // size_t fwrite(const void *restrict ptr, size_t size, size_t nitems, FILE *restrict stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/fwrite.html
    var bytesToWrite = nitems * size;
    if (bytesToWrite == 0) return 0;
    var bytesWritten = _write(stream, ptr, bytesToWrite);
    if (bytesWritten == -1) {
      if (FS.streams[stream]) FS.streams[stream].error = true;
      return -1;
    } else {
      return Math.floor(bytesWritten / size);
    }
  },
  popen__deps: ['__setErrNo', '$ERRNO_CODES'],
  popen: function(command, mode) {
    // FILE *popen(const char *command, const char *mode);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/popen.html
    // We allow only one process, so no pipes.
    ___setErrNo(ERRNO_CODES.EMFILE);
    return 0;
  },
  pclose__deps: ['__setErrNo', '$ERRNO_CODES'],
  pclose: function(stream) {
    // int pclose(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/pclose.html
    // We allow only one process, so no pipes.
    ___setErrNo(ERRNO_CODES.ECHILD);
    return -1;
  },
  perror__deps: ['puts', 'putc', 'strerror', '__errno_location'],
  perror: function(s) {
    // void perror(const char *s);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/perror.html
    if (s) {
      _puts(s);
      _putc(':'.charCodeAt(0));
      _putc(' '.charCodeAt(0));
    }
    var errnum = {{{ makeGetValue('___errno_location()', '0', 'i32') }}};
    _puts(_strerror(errnum));
  },
  remove__deps: ['unlink', 'rmdir'],
  remove: function(path) {
    // int remove(const char *path);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/remove.html
    var ret = _unlink(path);
    if (ret == -1) ret = _rmdir(path);
    return ret;
  },
  rename__deps: ['__setErrNo', '$ERRNO_CODES'],
  rename: function(old, new_) {
    // int rename(const char *old, const char *new);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/rename.html
    var oldObj = FS.analyzePath(Pointer_stringify(old));
    var newObj = FS.analyzePath(Pointer_stringify(new_));
    if (newObj.path == oldObj.path) {
      return 0;
    } else if (!oldObj.exists) {
      ___setErrNo(oldObj.error);
      return -1;
    } else if (oldObj.isRoot || oldObj.path == FS.currentPath) {
      ___setErrNo(ERRNO_CODES.EBUSY);
      return -1;
    } else if (newObj.path && newObj.path.indexOf(oldObj.path) == 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    } else if (newObj.exists && newObj.object.isFolder) {
      ___setErrNo(ERRNO_CODES.EISDIR);
      return -1;
    } else {
      delete oldObj.parentObject.contents[oldObj.name];
      newObj.parentObject.contents[newObj.name] = oldObj.object;
      return 0;
    }
  },
  rewind__deps: ['$FS', 'fseek'],
  rewind: function(stream) {
    // void rewind(FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/rewind.html
    _fseek(stream, 0, 0);  // SEEK_SET.
    if (stream in FS.streams) FS.streams[stream].error = false;
  },
  setvbuf: function(stream, buf, type, size) {
    // int setvbuf(FILE *restrict stream, char *restrict buf, int type, size_t size);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/setvbuf.html
    // TODO: Implement buffering.
    return 0;
  },
  setbuf__deps: ['setvbuf'],
  setbuf: function(stream, buf) {
    // void setbuf(FILE *restrict stream, char *restrict buf);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/setbuf.html
    if (buf) _setvbuf(stream, buf, 0, 8192);  // _IOFBF, BUFSIZ.
    else _setvbuf(stream, buf, 2, 8192);  // _IONBF, BUFSIZ.
  },
  tmpnam__deps: ['$FS'],
  tmpnam: function(s, dir, prefix) {
    // char *tmpnam(char *s);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/tmpnam.html
    // NOTE: The dir and prefix arguments are for internal use only.
    var folder = FS.findObject(dir || '/tmp');
    if (!folder || !folder.isFolder) {
      dir = '/tmp';
      folder = FS.findObject(dir);
      if (!folder || !folder.isFolder) return 0;
    }
    var name = prefix || 'file';
    do {
      name += String.fromCharCode(65 + Math.floor(Math.random() * 25));
    } while (name in folder.contents);
    var result = dir + '/' + name;
    if (!_tmpnam.buffer) _tmpnam.buffer = _malloc(256);
    if (!s) s = _tmpnam.buffer;
    for (var i = 0; i < result.length; i++) {
      {{{ makeSetValue('s', 'i', 'result.charCodeAt(i)', 'i8') }}};
    }
    {{{ makeSetValue('s', 'i', '0', 'i8') }}};
    return s;
  },
  tempnam__deps: ['tmpnam'],
  tempnam: function(dir, pfx) {
    // char *tempnam(const char *dir, const char *pfx);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/tempnam.html
    return _tmpnam(0, Pointer_stringify(dir), Pointer_stringify(pfx));
  },
  tmpfile__deps: ['tmpnam', 'fopen'],
  tmpfile: function() {
    // FILE *tmpfile(void);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/tmpfile.html
    // TODO: Delete the created file on closing.
    if (_tmpfile.mode) {
      _tmpfile.mode = allocate(intArrayFromString('w+'), 'i8', ALLOC_NORMAL);
    }
    return _fopen(_tmpnam(0), _tmpfile.mode);
  },
  ungetc__deps: ['$FS'],
  ungetc: function(c, stream) {
    // int ungetc(int c, FILE *stream);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/ungetc.html
    if (stream in FS.streams) {
      c = unSign(c & 0xFF);
      FS.streams[stream].ungotten.push(c);
      return c;
    } else {
      return -1;
    }
  },
  system__deps: ['__setErrNo', '$ERRNO_CODES'],
  system: function(command) {
    // int system(const char *command);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/system.html
    // Can't call external programs.
    ___setErrNo(ERRNO_CODES.EAGAIN);
    return -1;
  },
  fscanf__deps: ['$FS', '__setErrNo', '$ERRNO_CODES',
                 '_scanString', 'getc', 'ungetc'],
  fscanf: function(stream, format/*, ...*/) {
    // int fscanf(FILE *restrict stream, const char *restrict format, ... );
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/scanf.html
    if (stream in FS.streams) {
      var args = Array.prototype.slice.call(arguments, 2);
      var get = function() { return _fgetc(stream); };
      var unget = function(c) { return _ungetc(c, stream); };
      return __scanString(format, get, unget, args);
    } else {
      return -1;
    }
  },
  scanf__deps: ['fscanf'],
  scanf: function(format/*, ...*/) {
    // int scanf(const char *restrict format, ... );
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/scanf.html
    var args = Array.prototype.slice.call(arguments, 0);
    args.unshift({{{ makeGetValue('_stdin', '0', 'void*') }}});
    return _fscanf.apply(null, args);
  },
  sscanf__deps: ['_scanString'],
  sscanf: function(s, format/*, ...*/) {
    // int sscanf(const char *restrict s, const char *restrict format, ... );
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/scanf.html
    var index = 0;
    var get = function() { return {{{ makeGetValue('s', 'index++', 'i8') }}}; };
    var unget = function() { index--; };
    var args = Array.prototype.slice.call(arguments, 2);
    return __scanString(format, get, unget, args);
  },
  snprintf__deps: ['_formatString'],
  snprintf: function(s, n, format/*, ... */) {
    // int snprintf(char *restrict s, size_t n, const char *restrict format, ...);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/printf.html
    var args = Array.prototype.slice.call(arguments, 2);
    args.unshift(false);
    var result = __formatString.apply(null, args);
    var limit = (n === undefined) ? result.length
                                  : Math.min(result.length, n - 1);
    for (var i = 0; i < limit; i++) {
      {{{ makeSetValue('s', 'i', 'result[i]', 'i8') }}};
    }
    {{{ makeSetValue('s', 'i', '0', 'i8') }}};
    return result.length;
  },
  fprintf__deps: ['fwrite', '_formatString'],
  fprintf: function(stream, format/*, ... */) {
    // int fprintf(FILE *restrict stream, const char *restrict format, ...);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/printf.html
    var args = Array.prototype.slice.call(arguments, 1);
    args.unshift(false);
    var result = __formatString.apply(null, args);
    var buffer = allocate(result, 'i8', ALLOC_NORMAL);
    var ret = _fwrite(buffer, 1, result.length, stream);
    _free(buffer);
    return ret;
  },
  printf__deps: ['fprintf'],
  printf: function(format/*, ... */) {
    // int printf(const char *restrict format, ...);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/printf.html
    var args = Array.prototype.slice.call(arguments, 0);
    args.unshift({{{ makeGetValue('_stdout', '0', 'void*') }}});
    return _fprintf.apply(null, args);
  },
  sprintf__deps: ['snprintf'],
  sprintf: function(s, format/*, ... */) {
    // int sprintf(char *restrict s, const char *restrict format, ...);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/printf.html
    var args = [s, undefined].concat(Array.prototype.slice.call(arguments, 1));
    return _snprintf.apply(null, args);
  },
  vfprintf__deps: ['fwrite', '_formatString'],
  vfprintf: function(stream, format, ap) {
    // int vfprintf(FILE *restrict stream, const char *restrict format, va_list ap);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/vprintf.html
    var result = __formatString(true, format, ap);
    var buffer = allocate(result, 'i8', ALLOC_NORMAL);
    var ret = _fwrite(buffer, 1, result.length, stream);
    _free(buffer);
    return ret;
  },
  vsnprintf__deps: ['_formatString'],
  vsnprintf: function(s, n, format, ap) {
    // int vsnprintf(char *restrict s, size_t n, const char *restrict format, va_list ap);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/vprintf.html
    var result = __formatString(true, format, ap);
    var limit = (n === undefined) ? result.length
                                  : Math.min(result.length, n - 1);
    for (var i = 0; i < limit; i++) {
      {{{ makeSetValue('s', 'i', 'result[i]', 'i8') }}};
    }
    {{{ makeSetValue('s', 'i', '0', 'i8') }}};
    return result.length;
  },
  vprintf__deps: ['vfprintf'],
  vprintf: function(format, ap) {
    // int vprintf(const char *restrict format, va_list ap);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/vprintf.html
    return _vfprintf({{{ makeGetValue('_stdout', '0', 'void*') }}}, format, ap);
  },
  vsprintf__deps: ['vsnprintf'],
  vsprintf: function(s, format, ap) {
    // int vsprintf(char *restrict s, const char *restrict format, va_list ap);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/vprintf.html
    return _vsnprintf(s, undefined, format, ap);
  },
  // TODO: Implement v*scanf().
  __01fopen64_: 'fopen',
  __01fseeko64_: 'fseek',
  __01ftello64_: 'ftell',
  __01tmpfile64_: 'tmpfile',
  // TODO: Check if any other aliases are needed.
  _IO_getc: 'getc',
  _IO_putc: 'putc',
  _ZNSo3putEc: 'putchar',
  _ZNSo5flushEv__deps: ['fflush', 'stdout'],
  _ZNSo5flushEv: function() {
    _fflush({{{ makeGetValue('_stdout', '0', 'void*') }}});
  },

  // ==========================================================================
  // sys/mman.h
  // ==========================================================================

  mmap__deps: ['$FS'],
  mmap: function(start, num, prot, flags, stream, offset) {
    // FIXME: Leaky and non-shared.
    var info = FS.streams[stream];
    if (!info) return -1;
    return allocate(info.object.contents.slice(offset, offset+num),
                    'i8', ALLOC_NORMAL);
  },

  munmap: function(start, num) {
    // FIXME: Not really correct at all.
    _free(start);
  },

  // TODO: Implement mremap.

  // ==========================================================================
  // stdlib.h
  // ==========================================================================

  malloc: Runtime.staticAlloc,
  _Znwj: 'malloc',
  _Znaj: 'malloc',
  _Znam: 'malloc',
  _Znwm: 'malloc',

  free: function(){},
  _ZdlPv: 'free',
  _ZdaPv: 'free',

  calloc__deps: ['malloc'],
  calloc: function(n, s) {
    var ret = _malloc(n*s);
    _memset(ret, 0, n*s);
    return ret;
  },

  abs: 'Math.abs', // XXX should be integer?

  atoi: function(s) {
    return Math.floor(Number(Pointer_stringify(s)));
  },

  exit__deps: ['_exit'],
  exit: function(status) {
    __exit(status);
  },

  atexit: function(func, arg) {
    __ATEXIT__.push({ func: func, arg: arg });
  },
  __cxa_atexit: 'atexit',

  abort: function(code) {
    ABORT = true;
    throw 'ABORT: ' + code + ', at ' + (new Error().stack);
  },

  realloc__deps: ['memcpy'],
  realloc: function(ptr, size) {
    // Very simple, inefficient implementation - if you use a real malloc, best to use
    // a real realloc with it
    if (!size) {
      if (ptr) _free(ptr);
      return 0;
    }
    var ret = _malloc(size);
    if (ptr) {
      _memcpy(ret, ptr, size); // might be some invalid reads
      _free(ptr);
    }
    return ret;
  },

  strtod__deps: ['isspace', 'isdigit'],
  strtod: function(str, endptr) {
    // Skip space.
    while (_isspace(str)) str++;

    var chr;
    var ret = 0;

    // Get whole part.
    while(1) {
      chr = {{{ makeGetValue('str', 0, 'i8') }}};
      if (!_isdigit(chr)) break;
      ret = ret*10 + chr - '0'.charCodeAt(0);
      str++;
    }

    // Get fractional part.
    if ({{{ makeGetValue('str', 0, 'i8') }}} == '.'.charCodeAt(0)) {
      str++;
      var mul = 1/10;
      while(1) {
        chr = {{{ makeGetValue('str', 0, 'i8') }}};
        if (!_isdigit(chr)) break;
        ret += mul*(chr - '0'.charCodeAt(0));
        mul /= 10;
        str++;
      }
    }

    // Get exponent part.
    chr = {{{ makeGetValue('str', 0, 'i8') }}};
    if (chr == 'e'.charCodeAt(0) || chr == 'E'.charCodeAt(0)) {
      str++;
      var exponent = 0;
      var expNegative = false;
      chr = {{{ makeGetValue('str', 0, 'i8') }}};
      if (chr == '-'.charCodeAt(0)) {
        expNegative = true;
        str++;
      } else if (chr == '+'.charCodeAt(0)) {
        str++;
      }
      chr = {{{ makeGetValue('str', 0, 'i8') }}};
      while(1) {
        if (!_isdigit(chr)) break;
        exponent = exponent*10 + chr - '0'.charCodeAt(0);
        str++;
        chr = {{{ makeGetValue('str', 0, 'i8') }}};
      }
      if (expNegative) exponent = -exponent;
      ret *= Math.pow(10, exponent);
    }

    // Set end pointer.
    if (endptr) {
      {{{ makeSetValue('endptr', 0, 'str', '*') }}}
    }

    return ret;
  },

  qsort__deps: ['memcpy'],
  qsort: function(base, num, size, comparator) {
    // forward calls to the JavaScript sort method
    // first, sort the items logically
    comparator = FUNCTION_TABLE[comparator];
    var keys = [];
    for (var i = 0; i < num; i++) keys.push(i);
    keys.sort(function(a, b) {
      return comparator(base+a*size, base+b*size);
    });
    // apply the sort
    var temp = _malloc(num*size);
    _memcpy(temp, base, num*size);
    for (var i = 0; i < num; i++) {
      if (keys[i] == i) continue; // already in place
      _memcpy(base+i*size, temp+keys[i]*size, size);
    }
    _free(temp);
  },

  __environ: null,
  __buildEnvironment__deps: ['__environ'],
  __buildEnvironment: function(env) {
    // WARNING: Arbitrary limit!
    var MAX_ENV_VALUES = 64;
    var TOTAL_ENV_SIZE = 1024;

    // Statically allocate memory for the environment.
    var poolPtr;
    var envPtr;
    if (___environ === null) {
      poolPtr = allocate(TOTAL_ENV_SIZE, 'i8', ALLOC_STATIC);
      envPtr = allocate(MAX_ENV_VALUES * {{{ QUANTUM_SIZE }}},
                        'i8*', ALLOC_STATIC);
      {{{ makeSetValue('envPtr', '0', 'poolPtr', 'i8*') }}}
      ___environ = allocate([envPtr], 'i8**', ALLOC_STATIC);
    } else {
      envPtr = {{{ makeGetValue('___environ', '0', 'i8**') }}};
      poolPtr = {{{ makeGetValue('envPtr', '0', 'i8*') }}};
    }

    // Collect key=value lines.
    var strings = [];
    var totalSize = 0;
    for (var key in env) {
      if (typeof env[key] === 'string') {
        var line = key + '=' + env[key];
        strings.push(line);
        totalSize += line.length;
      }
    }
    if (totalSize > TOTAL_ENV_SIZE) {
      throw new Error('Environment size exceeded TOTAL_ENV_SIZE!');
    }

    // Make new.
    var ptrSize = {{{ Runtime.getNativeTypeSize('i8*') }}};
    for (var i = 0; i < strings.length; i++) {
      var line = strings[i];
      for (var j = 0; j < line.length; j++) {
        {{{ makeSetValue('poolPtr', 'j', 'line.charCodeAt(j)', 'i8') }}}
      }
      {{{ makeSetValue('poolPtr', 'j', '0', 'i8') }}}
      {{{ makeSetValue('envPtr', 'i * ptrSize', 'poolPtr', 'i8*') }}}
      poolPtr += line.length + 1;
    }
    {{{ makeSetValue('envPtr', 'strings.length * ptrSize', '0', 'i8*') }}}
  },
  $ENV__deps: ['__buildEnvironment'],
  $ENV__postset: '___buildEnvironment(ENV);',
  $ENV: {
    'USER': 'root',
    'PATH': '/',
    'PWD': '/',
    'HOME': '/',
    'LANG': 'en_US.UTF-8',
    '_': './this.program'
  },
  getenv__deps: ['$ENV'],
  getenv: function(name) {
    // char *getenv(const char *name);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/getenv.html
    if (name === 0) return 0;
    name = Pointer_stringify(name);
    if (!ENV.hasOwnProperty(name)) return 0;

    if (_getenv.ret) _free(_getenv.ret);
    _getenv.ret = allocate(intArrayFromString(ENV[name]), 'i8', ALLOC_NORMAL);
    return _getenv.ret;
  },
  clearenv__deps: ['$ENV', '__buildEnvironment'],
  clearenv: function(name) {
    // int clearenv (void);
    // http://www.gnu.org/s/hello/manual/libc/Environment-Access.html#index-clearenv-3107
    ENV = {};
    ___buildEnvironment(ENV);
    return 0;
  },
  setenv__deps: ['$ENV', '__buildEnvironment', '$ERRNO_CODES', '__setErrNo'],
  setenv: function(envname, envval, overwrite) {
    // int setenv(const char *envname, const char *envval, int overwrite);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/setenv.html
    if (envname === 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    }
    var name = Pointer_stringify(envname);
    var val = Pointer_stringify(envval);
    if (name === '' || name.indexOf('=') !== -1) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    }
    if (ENV.hasOwnProperty(name) && !overwrite) return 0;
    ENV[name] = val;
    ___buildEnvironment(ENV);
    return 0;
  },
  unsetenv__deps: ['$ENV', '__buildEnvironment', '$ERRNO_CODES', '__setErrNo'],
  unsetenv: function(name) {
    // int unsetenv(const char *name);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/unsetenv.html
    if (name === 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    }
    name = Pointer_stringify(name);
    if (name === '' || name.indexOf('=') !== -1) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    }
    if (ENV.hasOwnProperty(name)) {
      delete ENV[name];
      ___buildEnvironment(ENV);
    }
    return 0;
  },
  putenv__deps: ['$ENV', '__buildEnvironment', '$ERRNO_CODES', '__setErrNo'],
  putenv: function(string) {
    // int putenv(char *string);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/putenv.html
    // WARNING: According to the standard (and the glibc implementation), the
    //          string is taken by reference so future changes are reflected.
    //          We copy it instead, possibly breaking some uses.
    if (string === 0) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    }
    string = Pointer_stringify(string);
    var splitPoint = string.indexOf('=')
    if (string === '' || string.indexOf('=') === -1) {
      ___setErrNo(ERRNO_CODES.EINVAL);
      return -1;
    }
    var name = string.slice(0, splitPoint);
    var value = string.slice(splitPoint + 1);
    if (!(name in ENV) || ENV[name] !== value) {
      ENV[name] = value;
      ___buildEnvironment(ENV);
    }
    return 0;
  },

  getloadavg: function(loadavg, nelem) {
    // int getloadavg(double loadavg[], int nelem);
    // http://linux.die.net/man/3/getloadavg
    var limit = Math.min(nelem, 3);
    var doubleSize = {{{ Runtime.getNativeTypeSize('double') }}};
    for (var i = 0; i < limit; i++) {
      {{{ makeSetValue('loadavg', 'i * doubleSize', '0.1', 'double') }}}
    }
    return limit;
  },

  // ==========================================================================
  // string.h
  // ==========================================================================

  memcpy: function (dest, src, num, idunno) {
#if ASSERTIONS
    assert(num % 1 === 0, 'memcpy given ' + num + ' bytes to copy. Problem with QUANTUM_SIZE=1 corrections perhaps?');
#endif
    // || 0, since memcpy sometimes copies uninitialized areas XXX: Investigate why initializing alloc'ed memory does not fix that too
    {{{ makeCopyValues('dest', 'src', 'num', 'null', ' || 0') }}};
  },
  llvm_memcpy_i32: 'memcpy',
  llvm_memcpy_i64: 'memcpy',
  llvm_memcpy_p0i8_p0i8_i32: 'memcpy',
  llvm_memcpy_p0i8_p0i8_i64: 'memcpy',

  memmove__deps: ['memcpy'],
  memmove: function(dest, src, num, idunno) {
    // not optimized!
    if (num === 0) return; // will confuse malloc if 0
    var tmp = _malloc(num);
    _memcpy(tmp, src, num);
    _memcpy(dest, tmp, num);
    _free(tmp);
  },
  llvm_memmove_i32: 'memmove',
  llvm_memmove_i64: 'memmove',
  llvm_memmove_p0i8_p0i8_i32: 'memmove',
  llvm_memmove_p0i8_p0i8_i64: 'memmove',

  memset: function(ptr, value, num) {
    {{{ makeSetValues('ptr', '0', 'value', 'null', 'num') }}}
  },
  llvm_memset_i32: 'memset',
  llvm_memset_p0i8_i32: 'memset',
  llvm_memset_p0i8_i64: 'memset',

  strlen: function(ptr) {
    return String_len(ptr);
  },

  strspn: function(pstr, pset) {
    var str = String_copy(pstr, true);
    var set = String_copy(pset);
    var i = 0;
    while (set.indexOf(str[i]) != -1) i++; // Must halt, as 0 is in str but not set
    return i;
  },

  strcspn: function(pstr, pset) {
    var str = String_copy(pstr, true);
    var set = String_copy(pset, true);
    var i = 0;
    while (set.indexOf(str[i]) == -1) i++; // Must halt, as 0 is in both
    return i;
  },

  strcpy: function(pdest, psrc) {
    var i = 0;
    do {
      {{{ makeCopyValues('pdest+i', 'psrc+i', 1, 'i8') }}}
      i ++;
    } while ({{{ makeGetValue('psrc', 'i-1', 'i8') }}} != 0);
    return pdest;
  },

  strncpy: function(pdest, psrc, num) {
    var padding = false, curr;
    for (var i = 0; i < num; i++) {
      curr = padding ? 0 : {{{ makeGetValue('psrc', 'i', 'i8') }}};
      {{{ makeSetValue('pdest', 'i', 'curr', 'i8') }}}
      padding = padding || {{{ makeGetValue('psrc', 'i', 'i8') }}} == 0;
    }
    return pdest;
  },

  strcat__deps: ['strlen'],
  strcat: function(pdest, psrc) {
    var len = _strlen(pdest);
    var i = 0;
    do {
      {{{ makeCopyValues('pdest+len+i', 'psrc+i', 1, 'i8') }}}
      i ++;
    } while ({{{ makeGetValue('psrc', 'i-1', 'i8') }}} != 0);
    return pdest;
  },

  strncat__deps: ['strlen'],
  strncat: function(pdest, psrc, num) {
    var len = _strlen(pdest);
    var i = 0;
    while(1) {
      {{{ makeCopyValues('pdest+len+i', 'psrc+i', 1, 'i8') }}}
      if ({{{ makeGetValue('pdest', 'len+i', 'i8') }}} == 0) break;
      i ++;
      if (i == num) {
        {{{ makeSetValue('pdest', 'len+i', 0, 'i8') }}}
        break;
      }
    }
    return pdest;
  },

  strtol: function(ptr) {
    assert(!arguments[1] && !arguments[2], "We don't support all strtol params yet");
    return parseInt(Pointer_stringify(ptr));
  },

  strcmp__deps: ['strncmp'],
  strcmp: function(px, py) {
    return _strncmp(px, py, TOTAL_MEMORY);
  },

  strcasecmp__deps: ['strncasecmp'],
  strcasecmp: function(px, py) {
    return _strncasecmp(px, py, TOTAL_MEMORY);
  },

  strncmp: function(px, py, n) {
    var i = 0;
    while (i < n) {
      var x = {{{ makeGetValue('px', 'i', 'i8') }}};
      var y = {{{ makeGetValue('py', 'i', 'i8') }}};
      if (x == y && x == 0) return 0;
      if (x == 0) return -1;
      if (y == 0) return 1;
      if (x == y) {
        i ++;
        continue;
      } else {
        return x > y ? 1 : -1;
      }
    }
    return 0;
  },

  strncasecmp__deps: ['tolower'],
  strncasecmp: function(px, py, n) {
    var i = 0;
    while (i < n) {
      var x = _tolower({{{ makeGetValue('px', 'i', 'i8') }}});
      var y = _tolower({{{ makeGetValue('py', 'i', 'i8') }}});
      if (x == y && x == 0) return 0;
      if (x == 0) return -1;
      if (y == 0) return 1;
      if (x == y) {
        i ++;
        continue;
      } else {
        return x > y ? 1 : -1;
      }
    }
    return 0;
  },

  memcmp: function(p1, p2, num) {
    for (var i = 0; i < num; i++) {
      var v1 = {{{ makeGetValue('p1', 'i', 'i8') }}};
      var v2 = {{{ makeGetValue('p2', 'i', 'i8') }}};
      if (v1 != v2) return v1 > v2 ? 1 : -1;
    }
    return 0;
  },

  memchr: function(ptr, chr, num) {
    chr = unSign(chr);
    for (var i = 0; i < num; i++) {
      if ({{{ makeGetValue('ptr', 0, 'i8') }}} == chr) return ptr;
      ptr++;
    }
    return 0;
  },

  strstr: function(ptr1, ptr2) {
    var str1 = Pointer_stringify(ptr1);
    var str2 = Pointer_stringify(ptr2);
    var ret = str1.search(str2);
    return ret >= 0 ? ptr1 + ret : 0;
  },

  strchr: function(ptr, chr) {
    ptr--;
    do {
      ptr++;
      var val = {{{ makeGetValue('ptr', 0, 'i8') }}};
      if (val == chr) return ptr;
    } while (val);
    return 0;
  },

  strrchr__deps: ['strlen'],
  strrchr: function(ptr, chr) {
    var ptr2 = ptr + _strlen(ptr);
    do {
      if ({{{ makeGetValue('ptr2', 0, 'i8') }}} == chr) return ptr2;
      ptr2--;
    } while (ptr2 >= ptr);
    return 0;
  },

  strdup: function(ptr) {
    return allocate(String_copy(ptr, true), 'i8', ALLOC_NORMAL);
  },

  strpbrk: function(ptr1, ptr2) {
    var searchSet = Runtime.set.apply(null, String_copy(ptr2));
    while ({{{ makeGetValue('ptr1', 0, 'i8') }}}) {
      if ({{{ makeGetValue('ptr1', 0, 'i8') }}} in searchSet) return ptr1;
      ptr1++;
    }
    return 0;
  },

  // Compiled from newlib; for the original source and licensing, see library_strtok_r.c XXX will not work with typed arrays
  strtok_r: function(b,j,f){var a;a=null;var c,e;b=b;var i=b!=0;a:do if(i)a=0;else{b=HEAP[f];if(b!=0){a=0;break a}c=0;a=3;break a}while(0);if(a==0){a:for(;;){e=HEAP[b];b+=1;a=j;var g=e;i=a;a=2;b:for(;;){d=a==5?d:0;a=HEAP[i+d];if(a!=0==0){a=9;break a}var d=d+1;if(g==a)break b;else a=5}a=2}if(a==9)if(g==0)c=HEAP[f]=0;else{c=b+-1;a:for(;;){e=HEAP[b];b+=1;a=j;g=e;d=a;a=10;b:for(;;){h=a==13?h:0;a=HEAP[d+h];if(a==g!=0)break a;var h=h+1;if(a!=0)a=13;else break b}}if(e==0)b=0;else HEAP[b+-1]=0; HEAP[f]=b;c=c}else if(a==7){HEAP[f]=b;HEAP[b+-1]=0;c=b+-1}}return c},
  // TODO: Compile strtok() from source.

  strerror_r__deps: ['$ERRNO_CODES', '$ERRNO_MESSAGES', '__setErrNo'],
  strerror_r: function(errnum, strerrbuf, buflen) {
    if (errnum in ERRNO_MESSAGES) {
      if (ERRNO_MESSAGES[errnum].length > buflen - 1) {
        return ___setErrNo(ERRNO_CODES.ERANGE);
      } else {
        var msg = ERRNO_MESSAGES[errnum];
        for (var i = 0; i < msg.length; i++) {
          {{{ makeSetValue('strerrbuf', 'i', 'msg.charCodeAt(i)', 'i8') }}}
        }
        {{{ makeSetValue('strerrbuf', 'i', 0, 'i8') }}}
        return 0;
      }
    } else {
      return ___setErrNo(ERRNO_CODES.EINVAL);
    }
  },
  strerror__deps: ['strerror_r'],
  strerror: function(errnum) {
    if (!_strerror.buffer) _strerror.buffer = _malloc(256);
    _strerror_r(errnum, _strerror.buffer, 256);
    return _strerror.buffer;
  },

  // ==========================================================================
  // ctype.h
  // ==========================================================================

  isascii: function(chr) {
    return chr >= 0 && (chr & 0x80) == 0;
  },
  toascii: function(chr) {
    return chr & 0x7F;
  },
  toupper: function(chr) {
    if (chr >= 'a'.charCodeAt(0) && chr <= 'z'.charCodeAt(0)) {
      return chr - 'a'.charCodeAt(0) + 'A'.charCodeAt(0);
    } else {
      return chr;
    }
  },
  _toupper: 'toupper',
  tolower: function(chr) {
    if (chr >= 'A'.charCodeAt(0) && chr <= 'Z'.charCodeAt(0)) {
      return chr - 'A'.charCodeAt(0) + 'a'.charCodeAt(0);
    } else {
      return chr;
    }
  },
  _tolower: 'tolower',
  // The following functions are defined as macros in glibc.
  islower: function(chr) {
    return chr >= 'a'.charCodeAt(0) && chr <= 'z'.charCodeAt(0);
  },
  isupper: function(chr) {
    return chr >= 'A'.charCodeAt(0) && chr <= 'Z'.charCodeAt(0);
  },
  isalpha: function(chr) {
    return (chr >= 'a'.charCodeAt(0) && chr <= 'z'.charCodeAt(0)) ||
           (chr >= 'A'.charCodeAt(0) && chr <= 'Z'.charCodeAt(0));
  },
  isdigit: function(chr) {
    return chr >= '0'.charCodeAt(0) && chr <= '9'.charCodeAt(0);
  },
  isxdigit: function(chr) {
    return (chr >= '0'.charCodeAt(0) && chr <= '9'.charCodeAt(0)) ||
           (chr >= 'a'.charCodeAt(0) && chr <= 'f'.charCodeAt(0)) ||
           (chr >= 'A'.charCodeAt(0) && chr <= 'F'.charCodeAt(0));
  },
  isalnum: function(chr) {
    return (chr >= '0'.charCodeAt(0) && chr <= '9'.charCodeAt(0)) ||
           (chr >= 'a'.charCodeAt(0) && chr <= 'z'.charCodeAt(0)) ||
           (chr >= 'A'.charCodeAt(0) && chr <= 'Z'.charCodeAt(0));
  },
  ispunct: function(chr) {
    return (chr >= '!'.charCodeAt(0) && chr <= '/'.charCodeAt(0)) ||
           (chr >= ':'.charCodeAt(0) && chr <= '@'.charCodeAt(0)) ||
           (chr >= '['.charCodeAt(0) && chr <= '`'.charCodeAt(0)) ||
           (chr >= '{'.charCodeAt(0) && chr <= '~'.charCodeAt(0));
  },
  isspace: function(chr) {
    return chr in { 32: 0, 9: 0, 10: 0, 11: 0, 12: 0, 13: 0 };
  },
  isblank: function(chr) {
    return chr == ' '.charCodeAt(0) || chr == '\t'.charCodeAt(0);
  },
  iscntrl: function(chr) {
    return (0 <= chr && chr <= 0x1F) || chr === 0x7F;
  },
  isprint: function(chr) {
    return 0x1F < chr && chr < 0x7F;
  },
  isgraph: 'isprint',
  // Lookup tables for glibc ctype implementation.
  __ctype_b_loc: function() {
    // http://refspecs.freestandards.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/baselib---ctype-b-loc.html
    var me = ___ctype_b_loc;
    if (!me.ret) {
      var values = [
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
        0,0,0,0,0,0,0,0,0,0,2,2,2,2,2,2,2,2,2,8195,8194,8194,8194,8194,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,24577,49156,49156,49156,
        49156,49156,49156,49156,49156,49156,49156,49156,49156,49156,49156,49156,55304,55304,55304,55304,55304,55304,55304,55304,
        55304,55304,49156,49156,49156,49156,49156,49156,49156,54536,54536,54536,54536,54536,54536,50440,50440,50440,50440,50440,
        50440,50440,50440,50440,50440,50440,50440,50440,50440,50440,50440,50440,50440,50440,50440,49156,49156,49156,49156,49156,
        49156,54792,54792,54792,54792,54792,54792,50696,50696,50696,50696,50696,50696,50696,50696,50696,50696,50696,50696,50696,
        50696,50696,50696,50696,50696,50696,50696,49156,49156,49156,49156,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
      ];
      var i16size = {{{ Runtime.getNativeTypeSize('i16') }}};
      var arr = _malloc(values.length * i16size);
      for (var i = 0; i < values.length; i++) {
        {{{ makeSetValue('arr', 'i * i16size', 'values[i]', 'i16') }}}
      }
      me.ret = allocate([arr + 128 * i16size], 'i16*', ALLOC_NORMAL);
    }
    return me.ret;
  },
  __ctype_tolower_loc: function() {
    // http://refspecs.freestandards.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/libutil---ctype-tolower-loc.html
    var me = ___ctype_tolower_loc;
    if (!me.ret) {
      var values = [
        128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,
        158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,
        188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,
        218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,
        248,249,250,251,252,253,254,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,
        33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,97,98,99,100,101,102,103,
        104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,91,92,93,94,95,96,97,98,99,100,101,102,103,
        104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,
        134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,
        164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,
        194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
        224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,
        254,255
      ];
      var i32size = {{{ Runtime.getNativeTypeSize('i32') }}};
      var arr = _malloc(values.length * i32size);
      for (var i = 0; i < values.length; i++) {
        {{{ makeSetValue('arr', 'i * i32size', 'values[i]', 'i32') }}}
      }
      me.ret = allocate([arr + 128 * i32size], 'i32*', ALLOC_NORMAL);
    }
    return me.ret;
  },
  __ctype_toupper_loc: function() {
    // http://refspecs.freestandards.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/libutil---ctype-toupper-loc.html
    var me = ___ctype_toupper_loc;
    if (!me.ret) {
      var values = [
        128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,
        158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,
        188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,
        218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,
        248,249,250,251,252,253,254,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,
        33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,
        73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,
        81,82,83,84,85,86,87,88,89,90,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,
        145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,
        175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,
        205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,
        235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255
      ];
      var i32size = {{{ Runtime.getNativeTypeSize('i32') }}};
      var arr = _malloc(values.length * i32size);
      for (var i = 0; i < values.length; i++) {
        {{{ makeSetValue('arr', 'i * i32size', 'values[i]', 'i32') }}}
      }
      me.ret = allocate([arr + 128 * i32size], 'i32*', ALLOC_NORMAL);
    }
    return me.ret;
  },

  // ==========================================================================
  // LLVM specifics
  // ==========================================================================

  llvm_va_copy: function(ppdest, ppsrc) {
    {{{ makeCopyValues('ppdest', 'ppsrc', QUANTUM_SIZE, 'null') }}}
    /* Alternate implementation that copies the actual DATA; it assumes the va_list is prefixed by its size
    var psrc = IHEAP[ppsrc]-1;
    var num = IHEAP[psrc]; // right before the data, is the number of (flattened) values
    var pdest = _malloc(num+1);
    _memcpy(pdest, psrc, num+1);
    IHEAP[ppdest] = pdest+1;
    */
  },

  llvm_bswap_i32: function(x) {
    x = unSign(x, 32);
    var bytes = [];
    for (var i = 0; i < 4; i++) {
      bytes[i] = x & 255;
      x >>= 8;
    }
    var ret = 0;
    for (i = 0; i < 4; i++) {
      ret <<= 8;
      ret += bytes[i];
    }
    return ret;
  },

  __assert_fail: function(condition, file, line) {
    ABORT = true;
    throw 'Assertion failed: ' + Pointer_stringify(condition);//JSON.stringify(arguments)//condition;
  },

  __cxa_guard_acquire: function() {
    return 1;
  },
  __cxa_guard_release: function() {
    return 1;
  },

  // Exceptions - minimal support, only (...) for now (no actual exception objects can be caught)
  __cxa_allocate_exception: function(size) {
    return _malloc(size); // warning: leaked
  },
  __cxa_throw: function(ptr, data, dunno) {
#if EXCEPTION_DEBUG
    print('Compiled code throwing an exception, ' + [ptr,data,dunno] + ', at ' + new Error().stack);
#endif
    throw ptr;
  },
  llvm_eh_exception: function() {
    return 'code-generated exception: ' + (new Error().stack);
  },
  llvm_eh_selector: function(exception, personality, num) {
    return 0;
  },
  __cxa_begin_catch: function(ptr) {
  },
  __cxa_end_catch: function(ptr) {
  },

  __cxa_call_unexpected: function(exception) {
    ABORT = true;
    throw exception;
  },

  __gxx_personality_v0: function() {
  },

  llvm_umul_with_overflow_i32: function(x, y) {
    return {
      f0: x*y,
      f1: 0 // We never overflow... for now
    };
  },

  llvm_stacksave: function() {
    var self = _llvm_stacksave;
    if (!self.LLVM_SAVEDSTACKS) {
      self.LLVM_SAVEDSTACKS = [];
    }
    self.LLVM_SAVEDSTACKS.push(STACKTOP);
    return self.LLVM_SAVEDSTACKS.length-1;
  },
  llvm_stackrestore: function(p) {
    var self = _llvm_stacksave;
    var ret = self.LLVM_SAVEDSTACKS[p];
    self.LLVM_SAVEDSTACKS.splice(p, 1);
    return ret;
  },

  __cxa_pure_virtual: function() {
    ABORT = true;
    throw 'Pure virtual function called!';
  },

  llvm_flt_rounds: function() {
    return -1; // 'indeterminable' for FLT_ROUNDS
  },

  // ==========================================================================
  // iostream.h
  // ==========================================================================

  // TODO: Document; compile from real implementation.

  _ZNSt8ios_base4InitC1Ev: function() {
    // need valid 'file descriptors'
    //__ZSt4cout = 1;
    //__ZSt4cerr = 2;
  },
  _ZNSt8ios_base4InitD1Ev: '_ZNSt8ios_base4InitC1Ev',
  _ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_: 0, // endl
  _ZNSolsEd__deps: ['putchar'],
  _ZNSolsEd: function(undefined_stream, data) {
    _putchar('\n'.charCodeAt(0));
  },
  _ZNSolsEPFRSoS_E: '_ZNSolsEd',
  _ZNSolsEi__deps: ['putchar'],
  _ZNSolsEi: function(undefined_stream, data) {
    var str = String(data);
    for (var i = 0; i < str.length; i++) {
      _putchar(str.charCodeAt(i));
    }
  },
  _ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc__deps: ['fputs', 'stdout'],
  _ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc: function(undefined_stream, data) {
    _fputs(data, {{{ makeGetValue('_stdout', '0', 'void*') }}});
  },
  _ZSt16__ostream_insertIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_PKS3_i: '_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc',

  // ==========================================================================
  // math.h
  // ==========================================================================

  cos: 'Math.cos',
  cosf: 'Math.cos',
  sin: 'Math.sin',
  sinf: 'Math.sin',
  tan: 'Math.tan',
  tanf: 'Math.tan',
  acos: 'Math.acos',
  acosf: 'Math.acos',
  asin: 'Math.asin',
  asinf: 'Math.asin',
  atan: 'Math.atan',
  atanf: 'Math.atan',
  atan2: 'Math.atan2',
  atan2f: 'Math.atan2',
  exp: 'Math.exp',
  expf: 'Math.exp',
  log: 'Math.log',
  logf: 'Math.log',
  sqrt: 'Math.sqrt',
  sqrtf: 'Math.sqrt',
  fabs: 'Math.abs',
  fabsf: 'Math.abs',
  ceil: 'Math.ceil',
  ceilf: 'Math.ceil',
  floor: 'Math.floor',
  floorf: 'Math.floor',
  pow: 'Math.pow',
  powf: 'Math.powf',
  llvm_sqrt_f32: 'Math.sqrt',
  llvm_sqrt_f64: 'Math.sqrt',
  llvm_pow_f32: 'Math.pow',
  llvm_pow_f64: 'Math.pow',
  llvm_log_f32: 'Math.log',
  llvm_log_f64: 'Math.log',
  llvm_exp_f32: 'Math.exp',
  llvm_exp_f64: 'Math.exp',
  ldexp: function(x, exp_) {
    return x * Math.pow(2, exp_);
  },
  ldexpf: 'ldexp',
  scalb: 'ldexp',
  scalbn: 'ldexp',
  scalbnf: 'ldexp',
  scalbln: 'ldexp',
  scalblnf: 'ldexp',

  modf: function(x, intpart) {
    {{{ makeSetValue('intpart', 0, 'Math.floor(x)', 'double') }}}
    return x - {{{ makeGetValue('intpart', 0, 'double') }}};
  },
  modff: function(x, intpart) {
    {{{ makeSetValue('intpart', 0, 'Math.floor(x)', 'float') }}}
    return x - {{{ makeGetValue('intpart', 0, 'float') }}};
  },
  frexp: function(x, exp_addr) {
    var sig = 0, exp_ = 0;
    if (x !== 0) {
      var raw_exp = Math.log(x)/Math.log(2);
      exp_ = Math.ceil(raw_exp);
      if (exp_ === raw_exp) exp_ += 1;
      sig = x/Math.pow(2, exp_);
    }
    {{{ makeSetValue('exp_addr', 0, 'exp_', 'i32') }}}
    return sig;
  },
  frexpf: 'frexp',
  finite: function(x) {
    return isFinite(x);
  },
  __finite: 'finite',
  isinf: function(x) {
    return !isNaN(x) && !isFinite(x);
  },
  __isinf: 'isinf',
  isnan: function(x) {
    return isNaN(x);
  },
  __isnan: 'isnan',
  copysign: function(a, b) {
      if (a < 0 === b < 0) return a;
      return -a;
  },
  copysignf: 'copysign',
  hypot: function(a, b) {
     return Math.sqrt(a*a + b*b);
  },
  hypotf: 'hypot',
  sinh: function(x) {
    var p = Math.pow(Math.E, x);
    return (p - (1 / p)) / 2;
  },
  sinhf: 'sinh',
  cosh: function(x) {
    var p = Math.pow(Math.E, x);
    return (p + (1 / p)) / 2;
  },
  coshf: 'cosh',
  tanh__deps: ['sinh', 'cosh'],
  tanh: function(x) {
    return _sinh(x) / _cosh(x);
  },
  tanhf: 'tanh',
  asinh: function(x) {
    return Math.log(x + Math.sqrt(x * x + 1));
  },
  asinhf: 'asinh',
  acosh: function(x) {
    return Math.log(x * 1 + Math.sqrt(x * x - 1));
  },
  acoshf: 'acosh',
  atanh: function(x) {
    return Math.log((1 + x) / (1 - x)) / 2;
  },
  atanhf: 'atanh',
  exp2: function(x) {
    return Math.pow(2, x);
  },
  exp2f: 'exp2',
  expm1: function(x) {
    return Math.exp(x) - 1;
  },
  expm1f: 'expm1',
  round: function(x) {
    return (x < 0) ? -Math.round(-x) : Math.round(x);
  },
  roundf: 'round',
  lround: 'round',
  lroundf: 'round',
  llround: 'round',
  llroundf: 'round',
  rint: function(x) {
    return (x > 0) ? -Math.round(-x) : Math.round(x);
  },
  rintf: 'rint',
  lrint: 'rint',
  lrintf: 'rint',
  llrint: 'rint',
  llrintf: 'rint',
  nearbyint: 'rint',
  nearbyintf: 'rint',
  trunc: function(x) {
    return (x < 0) ? Math.ceil(x) : Math.floor(x);
  },
  truncf: 'trunc',
  fdim: function(x, y) {
    return (x > y) ? x - y : 0;
  },
  fdimf: 'fdim',
  fmax: function(x, y) {
    return isNaN(x) ? y : isNaN(y) ? x : Math.max(x, y);
  },
  fmaxf: 'fmax',
  fmin: function(x, y) {
    return isNaN(x) ? y : isNaN(y) ? x : Math.max(x, y);
  },
  fminf: 'fmin',
  fma: function(x, y, z) {
    return x * y + z;
  },
  fmaf: 'fma',
  fmod: function(x, y) {
    return x % y;
  },
  fmodf: 'fmod',
  remainder: 'fmod',
  remainderf: 'fmod',
  log10: function(x) {
    return Math.log(x) / Math.LN10;
  },
  log10f: 'log10',
  log1p: function(x) {
    return Math.log(1 + x);
  },
  log1pf: 'log1p',
  log2: function(x) {
    return Math.log(x) / Math.LN2;
  },
  log2f: 'log2',
  nan: function(x) {
    return NaN;
  },
  nanf: 'nan',

  // ==========================================================================
  // sys/utsname.h
  // ==========================================================================

  __utsname_struct_layout: Runtime.generateStructInfo(null, '%struct.utsname'),
  uname__deps: ['__utsname_struct_layout'],
  uname: function(name) {
    // int uname(struct utsname *name);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/uname.html
    function copyString(element, value) {
      var offset = ___utsname_struct_layout[element];
      for (var i = 0; i < value.length; i++) {
        {{{ makeSetValue('name', 'offset + i', 'value.charCodeAt(i)', 'i8') }}}
      }
      {{{ makeSetValue('name', 'offset + i', '0', 'i8') }}}
    }
    if (name === 0) {
      return -1;
    } else {
      copyString('sysname', 'Emscripten');
      copyString('nodename', 'emscripten');
      copyString('release', '1.0');
      copyString('version', '#1');
      copyString('machine', 'x86-JS');
      return 0;
    }
  },

  // ==========================================================================
  // dlfcn.h - Dynamic library loading
  //
  // Some limitations:
  //
  //  * Minification on each file separately may not work, as they will
  //    have different shortened names. You can in theory combine them, then
  //    minify, then split... perhaps.
  //
  //  * LLVM optimizations may fail. If the child wants to access a function
  //    in the parent, LLVM opts may remove it from the parent when it is
  //    being compiled. Not sure how to tell LLVM to not do so.
  // ==========================================================================

  // Data for dlfcn.h.
  $DLFCN_DATA: {
    error: null,
    errorMsg: null,
    loadedLibs: {}, // handle -> [refcount, name, lib_object]
    loadedLibNames: {}, // name -> handle
  },
  // void* dlopen(const char* filename, int flag);
  dlopen__deps: ['$DLFCN_DATA', '$FS', '$ENV'],
  dlopen: function(filename, flag) {
    // void *dlopen(const char *file, int mode);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/dlopen.html
    filename = (ENV['LD_LIBRARY_PATH'] || '/') + Pointer_stringify(filename);

    if (DLFCN_DATA.loadedLibNames[filename]) {
      // Already loaded; increment ref count and return.
      var handle = DLFCN_DATA.loadedLibNames[filename];
      DLFCN_DATA.loadedLibs[handle].refcount++;
      return handle;
    }

    var target = FS.findObject(filename);
    if (!target || target.isFolder || target.isDevice) {
      DLFCN_DATA.errorMsg = 'Could not find dynamic lib: ' + filename;
      return 0;
    } else {
      FS.forceLoadFile(target);
      var lib_data = intArrayToString(target.contents);
    }

    try {
      var lib_module = eval(lib_data)(FUNCTION_TABLE.length);
    } catch (e) {
#if ASSERTIONS
      print('Error in loading dynamic library: ' + e);
#endif
      DLFCN_DATA.errorMsg = 'Could not evaluate dynamic lib: ' + filename;
      return 0;
    }

    // Not all browsers support Object.keys().
    var handle = 1;
    for (var key in DLFCN_DATA.loadedLibs) {
      if (DLFCN_DATA.loadedLibs.hasOwnProperty(key)) handle++;
    }

    DLFCN_DATA.loadedLibs[handle] = {
      refcount: 1,
      name: filename,
      module: lib_module,
      cached_functions: {}
    };
    DLFCN_DATA.loadedLibNames[filename] = handle;

    // We don't care about RTLD_NOW and RTLD_LAZY.
    if (flag & 256) { // RTLD_GLOBAL
      for (var ident in lib_module) {
        if (lib_module.hasOwnProperty(ident)) {
          Module[ident] = lib_module[ident];
        }
      }
    }

    return handle;
  },
  // int dlclose(void* handle);
  dlclose__deps: ['$DLFCN_DATA'],
  dlclose: function(handle) {
    // int dlclose(void *handle);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/dlclose.html
    if (!DLFCN_DATA.loadedLibs[handle]) {
      DLFCN_DATA.errorMsg = 'Tried to dlclose() unopened handle: ' + handle;
      return 1;
    } else {
      var lib_record = DLFCN_DATA.loadedLibs[handle];
      if (lib_record.refcount-- == 0) {
        delete DLFCN_DATA.loadedLibNames[lib_record.name];
        delete DLFCN_DATA.loadedLibs[handle];
      }
      return 0;
    }
  },
  // void* dlsym(void* handle, const char* symbol);
  dlsym__deps: ['$DLFCN_DATA'],
  dlsym: function(handle, symbol) {
    // void *dlsym(void *restrict handle, const char *restrict name);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/dlsym.html
    symbol = '_' + Pointer_stringify(symbol);

    if (!DLFCN_DATA.loadedLibs[handle]) {
      DLFCN_DATA.errorMsg = 'Tried to dlsym() from an unopened handle: ' + handle;
      return 0;
    } else {
      var lib = DLFCN_DATA.loadedLibs[handle];
      if (!lib.module.hasOwnProperty(symbol)) {
        DLFCN_DATA.errorMsg = ('Tried to lookup unknown symbol "' + symbol +
                               '" in dynamic lib: ' + lib.name);
        return 0;
      } else {
        if (lib.cached_functions.hasOwnProperty(symbol)) {
          return lib.cached_functions[symbol];
        } else {
          var result = lib.module[symbol];
          if (typeof result == 'function') {
            FUNCTION_TABLE.push(result);
            FUNCTION_TABLE.push(0);
            result = FUNCTION_TABLE.length - 2;
            lib.cached_functions = result;
          }
          return result;
        }
      }
    }
  },
  // char* dlerror(void);
  dlerror__deps: ['$DLFCN_DATA'],
  dlerror: function() {
    // char *dlerror(void);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/dlerror.html
    if (DLFCN_DATA.errorMsg === null) {
      return 0;
    } else {
      if (DLFCN_DATA.error) _free(DLFCN_DATA.error);
      var msgArr = Module.intArrayFromString(DLFCN_DATA.errorMsg);
      DLFCN_DATA.error = allocate(msgArr, 'i8', ALLOC_NORMAL);
      DLFCN_DATA.errorMsg = null;
      return DLFCN_DATA.error;
    }
  },

  // ==========================================================================
  // pwd.h
  // ==========================================================================

  // TODO: Implement.
  // http://pubs.opengroup.org/onlinepubs/009695399/basedefs/pwd.h.html
  getpwuid: function(uid) {
    return 0; // NULL
  },

  // ==========================================================================
  // time.h
  // ==========================================================================

  clock: function() {
    if (_clock.start === undefined) _clock.start = new Date();
    return (Date.now() - _clock.start.getTime()) * 1000;
  },

  time: function(ptr) {
    var ret = Math.floor(Date.now()/1000);
    if (ptr) {
      {{{ makeSetValue('ptr', 0, 'ret', 'i32') }}}
    }
    return ret;
  },

  difftime: function(time1, time0) {
    return time1 - time0;
  },

  __tm_struct_layout: Runtime.generateStructInfo(null, '%struct.tm'),
  // Statically allocated time struct.
  __tm_current: 0,
  // Statically allocated timezone strings.
  __tm_timezones: {},
  // Statically allocated time strings.
  __tm_formatted: 0,

  mktime__deps: ['__tm_struct_layout', 'tzset'],
  mktime: function(tmPtr) {
    _tzset();
    var offsets = ___tm_struct_layout;
    var year = {{{ makeGetValue('tmPtr', 'offsets.tm_year', 'i32') }}};
    var timestamp = new Date(year >= 1900 ? year : year + 1900,
                             {{{ makeGetValue('tmPtr', 'offsets.tm_mon', 'i32') }}},
                             {{{ makeGetValue('tmPtr', 'offsets.tm_mday', 'i32') }}},
                             {{{ makeGetValue('tmPtr', 'offsets.tm_hour', 'i32') }}},
                             {{{ makeGetValue('tmPtr', 'offsets.tm_min', 'i32') }}},
                             {{{ makeGetValue('tmPtr', 'offsets.tm_sec', 'i32') }}},
                             0).getTime() / 1000;
    {{{ makeSetValue('tmPtr', 'offsets.tm_wday', 'new Date(timestamp).getDay()', 'i32') }}}
    var yday = Math.round((timestamp - (new Date(year, 0, 1)).getTime()) / (1000 * 60 * 60 * 24));
    {{{ makeSetValue('tmPtr', 'offsets.tm_yday', 'yday', 'i32') }}}
    return timestamp;
  },
  timelocal: 'mktime',

  gmtime__deps: ['malloc', '__tm_struct_layout', '__tm_current', 'gmtime_r'],
  gmtime: function(time) {
    if (!___tm_current) ___tm_current = _malloc(___tm_struct_layout.__size__);
    return _gmtime_r(time, ___tm_current);
  },

  gmtime_r__deps: ['__tm_struct_layout', '__tm_timezones'],
  gmtime_r: function(time, tmPtr) {
    var date = new Date({{{ makeGetValue('time', 0, 'i32') }}}*1000);
    var offsets = ___tm_struct_layout;
    {{{ makeSetValue('tmPtr', 'offsets.tm_sec', 'date.getUTCSeconds()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_min', 'date.getUTCMinutes()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_hour', 'date.getUTCHours()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_mday', 'date.getUTCDate()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_mon', 'date.getUTCMonth()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_year', 'date.getUTCFullYear()-1900', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_wday', 'date.getUTCDay()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_gmtoff', '0', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_isdst', '0', 'i32') }}}

    var start = new Date(date.getFullYear(), 0, 1);
    var yday = Math.round((date.getTime() - start.getTime()) / (1000 * 60 * 60 * 24));
    {{{ makeSetValue('tmPtr', 'offsets.tm_yday', 'yday', 'i32') }}}

    var timezone = "GMT";
    if (!(timezone in ___tm_timezones)) {
      ___tm_timezones[timezone] = allocate(intArrayFromString(timezone), 'i8', ALLOC_NORMAL);
    }
    {{{ makeSetValue('tmPtr', 'offsets.tm_zone', '___tm_timezones[timezone]', 'i32') }}}

    return tmPtr;
  },

  timegm__deps: ['mktime'],
  timegm: function(tmPtr) {
    _tzset();
    var offset = {{{ makeGetValue('_timezone', 0, 'i32') }}};
    var daylight = {{{ makeGetValue('_daylight', 0, 'i32') }}};
    daylight = (daylight == 1) ? 60 * 60 : 0;
    var ret = _mktime(tmPtr) + offset - daylight;
    return ret;
  },

  localtime__deps: ['malloc', '__tm_struct_layout', '__tm_current', 'localtime_r'],
  localtime: function(time) {
    if (!___tm_current) ___tm_current = _malloc(___tm_struct_layout.__size__);
    return _localtime_r(time, ___tm_current);
  },

  localtime_r__deps: ['__tm_struct_layout', '__tm_timezones', 'tzset'],
  localtime_r: function(time, tmPtr) {
    _tzset();
    var offsets = ___tm_struct_layout;
    var date = new Date({{{ makeGetValue('time', 0, 'i32') }}}*1000);
    {{{ makeSetValue('tmPtr', 'offsets.tm_sec', 'date.getSeconds()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_min', 'date.getMinutes()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_hour', 'date.getHours()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_mday', 'date.getDate()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_mon', 'date.getMonth()', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_year', 'date.getFullYear()-1900', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_wday', 'date.getDay()', 'i32') }}}

    var start = new Date(date.getFullYear(), 0, 1);
    var yday = Math.floor((date.getTime() - start.getTime()) / (1000 * 60 * 60 * 24));
    {{{ makeSetValue('tmPtr', 'offsets.tm_yday', 'yday', 'i32') }}}
    {{{ makeSetValue('tmPtr', 'offsets.tm_gmtoff', 'start.getTimezoneOffset() * 60', 'i32') }}}

    var dst = Number(start.getTimezoneOffset() != date.getTimezoneOffset());
    {{{ makeSetValue('tmPtr', 'offsets.tm_isdst', 'dst', 'i32') }}}

    var timezone = date.toString().match(/\(([A-Z]+)\)/)[1];
    if (!(timezone in ___tm_timezones)) {
      ___tm_timezones[timezone] = allocate(intArrayFromString(timezone), 'i8', ALLOC_NORMAL);
    }
    {{{ makeSetValue('tmPtr', 'offsets.tm_zone', '___tm_timezones[timezone]', 'i32') }}}

    return tmPtr;
  },

  asctime__deps: ['malloc', '__tm_formatted', 'asctime_r'],
  asctime: function(tmPtr) {
    if (!___tm_formatted) ___tm_formatted = _malloc(26);
    return _asctime_r(tmPtr, ___tm_formatted);
  },

  asctime_r__deps: ['__tm_formatted', 'mktime'],
  asctime_r: function(tmPtr, buf) {
    var date = new Date(_mktime(tmPtr)*1000);
    var formatted = date.toString();
    var datePart = formatted.replace(/\d{4}.*/, '').replace(/ 0/, '  ');
    var timePart = formatted.match(/\d{2}:\d{2}:\d{2}/)[0];
    formatted = datePart + timePart + ' ' + date.getFullYear() + '\n';
    formatted.split('').forEach(function(chr, index) {
      {{{ makeSetValue('buf', 'index', 'chr.charCodeAt(0)', 'i8') }}}
    });
    {{{ makeSetValue('buf', '25', '0', 'i8') }}}
    return buf;
  },

  ctime__deps: ['localtime', 'asctime'],
  ctime: function(timer) {
    return _asctime(_localtime(timer));
  },

  ctime_r__deps: ['localtime', 'asctime'],
  ctime_r: function(timer, buf) {
    return _asctime_r(_localtime_r(timer, ___tm_current), buf);
  },

  dysize: function(year) {
    var leap = ((year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0)));
    return leap ? 366 : 365;
  },

  // TODO: Initialize these to defaults on startup from system settings.
  tzname: null,
  daylight: null,
  timezone: null,
  tzset__deps: ['malloc', 'tzname', 'daylight', 'timezone'],
  tzset: function() {
    // TODO: Use (malleable) environment variables instead of system settings.
    if (_tzname !== null) return;

    _timezone = _malloc(QUANTUM_SIZE);
    {{{ makeSetValue('_timezone', '0', '-(new Date()).getTimezoneOffset() * 60', 'i32') }}}

    _daylight = _malloc(QUANTUM_SIZE);
    var winter = new Date(2000, 0, 1);
    var summer = new Date(2000, 6, 1);
    {{{ makeSetValue('_daylight', '0', 'Number(winter.getTimezoneOffset() != summer.getTimezoneOffset())', 'i32') }}}

    var winterName = winter.toString().match(/\(([A-Z]+)\)/)[1];
    var summerName = summer.toString().match(/\(([A-Z]+)\)/)[1];
    var winterNamePtr = allocate(intArrayFromString(winterName), 'i8', ALLOC_NORMAL);
    var summerNamePtr = allocate(intArrayFromString(summerName), 'i8', ALLOC_NORMAL);
    _tzname = _malloc(2 * QUANTUM_SIZE);
    {{{ makeSetValue('_tzname', '0', 'winterNamePtr', 'i32') }}}
    {{{ makeSetValue('_tzname', QUANTUM_SIZE, 'summerNamePtr', 'i32') }}}
  },

  stime__deps: ['$ERRNO_CODES', '__setErrNo'],
  stime: function(when) {
    ___setErrNo(ERRNO_CODES.EPERM);
    return -1;
  },

  // TODO: Implement strftime(), strptime() and getdate().

  // ==========================================================================
  // sys/time.h
  // ==========================================================================

  // TODO: Implement remaining functions.
  // http://pubs.opengroup.org/onlinepubs/000095399/basedefs/sys/time.h.html
  gettimeofday: function(ptr) {
    // %struct.timeval = type { i32, i32 }
    var indexes = Runtime.calculateStructAlignment({ fields: ['i32', 'i32'] });
    var now = Date.now();
    {{{ makeSetValue('ptr', 'indexes[0]', 'Math.floor(now/1000)', 'i32') }}} // seconds
    {{{ makeSetValue('ptr', 'indexes[1]', 'Math.floor((now-1000*Math.floor(now/1000))*1000)', 'i32') }}} // microseconds
    return 0;
  },

  // ==========================================================================
  // sys/times.h
  // ==========================================================================

  __tms_struct_layout: Runtime.generateStructInfo(null, '%struct.tms'),
  times__deps: ['__tms_struct_layout'],
  times: function(buffer) {
    // clock_t times(struct tms *buffer);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/times.html
    // NOTE: This is fake, since we can't calculate real CPU time usage in JS.
    if (buffer !== 0) {
      {{{ makeSetValues('buffer', '0', '0', 'null', '___tms_struct_layout.__size__') }}}
    }
    return 0;
  },

  // ==========================================================================
  // sys/types.h
  // ==========================================================================

  // NOTE: These are fake, since we don't support the C device creation API.
  // http://www.kernel.org/doc/man-pages/online/pages/man3/minor.3.html
  makedev: function(maj, min) {
    return 0;
  },
  gnu_dev_makedev: 'makedev',
  major: function(dev) {
    return 0;
  },
  gnu_dev_major: 'major',
  minor: function(dev) {
    return 0;
  },
  gnu_dev_minor: 'minor',

  // ==========================================================================
  // setjmp.h
  // ==========================================================================

  _setjmp: function(env) {
    // XXX print('WARNING: setjmp() not really implemented, will fail if longjmp() is actually called');
    return 0;
  },

  _longjmp: function(env, val) {
    // not really working...
    assert(0);
  },

  // ==========================================================================
  // signal.h
  // ==========================================================================

  signal: function(sig, func) {
    // TODO
    return 0;
  },
  __libc_current_sigrtmin: function() {
    return 0;
  },
  __libc_current_sigrtmax: function() {
    return 0;
  },
  kill__deps: ['$ERRNO_CODES', '__setErrNo'],
  kill: function(pid, sig) {
    // int kill(pid_t pid, int sig);
    // http://pubs.opengroup.org/onlinepubs/000095399/functions/kill.html
    // Makes no sense in a single-process environment.
    ___setErrNo(ERRNO_CODES.EPERM);
    return -1;
  },
  killpg: 'kill',

  // ==========================================================================
  // sys/wait.h
  // ==========================================================================

  wait__deps: ['$ERRNO_CODES', '__setErrNo'],
  wait: function(stat_loc) {
    // pid_t wait(int *stat_loc);
    // http://pubs.opengroup.org/onlinepubs/009695399/functions/wait.html
    // Makes no sense in a single-process environment.
    ___setErrNo(ERRNO_CODES.ECHILD);
    return -1;
  },
  // NOTE: These aren't really the same, but we use the same stub for them all.
  waitid: 'wait',
  waitpid: 'wait',
  wait3: 'wait',
  wait4: 'wait',

  // ==========================================================================
  // locale.h
  // ==========================================================================

  setlocale: function(category, locale) {
    return 0;
  },

  localeconv: function() {
    // %struct.timeval = type { char* decimal point, other stuff... }
    // var indexes = Runtime.calculateStructAlignment({ fields: ['i32', 'i32'] });
    var me = _localeconv;
    if (!me.ret) {
      me.ret = allocate([allocate(intArrayFromString('.'), 'i8', ALLOC_NORMAL)], 'i8', ALLOC_NORMAL); // just decimal point, for now
    }
    return me.ret;
  },

  // ==========================================================================
  // langinfo.h
  // ==========================================================================

  // TODO: Implement for real.
  nl_langinfo: function(item) {
    var me = _nl_langinfo;
    if (!me.ret) {
      me.ret = allocate(intArrayFromString("eh?"), 'i8', ALLOC_NORMAL);
    }
    return me.ret;
  },

  // ==========================================================================
  // errno.h
  // ==========================================================================

  $ERRNO_CODES: {
    E2BIG: 7,
    EACCES: 13,
    EADDRINUSE: 98,
    EADDRNOTAVAIL: 99,
    EAFNOSUPPORT: 97,
    EAGAIN: 11,
    EALREADY: 114,
    EBADF: 9,
    EBADMSG: 74,
    EBUSY: 16,
    ECANCELED: 125,
    ECHILD: 10,
    ECONNABORTED: 103,
    ECONNREFUSED: 111,
    ECONNRESET: 104,
    EDEADLK: 35,
    EDESTADDRREQ: 89,
    EDOM: 33,
    EDQUOT: 122,
    EEXIST: 17,
    EFAULT: 14,
    EFBIG: 27,
    EHOSTUNREACH: 113,
    EIDRM: 43,
    EILSEQ: 84,
    EINPROGRESS: 115,
    EINTR: 4,
    EINVAL: 22,
    EIO: 5,
    EISCONN: 106,
    EISDIR: 21,
    ELOOP: 40,
    EMFILE: 24,
    EMLINK: 31,
    EMSGSIZE: 90,
    EMULTIHOP: 72,
    ENAMETOOLONG: 36,
    ENETDOWN: 100,
    ENETRESET: 102,
    ENETUNREACH: 101,
    ENFILE: 23,
    ENOBUFS: 105,
    ENODATA: 61,
    ENODEV: 19,
    ENOENT: 2,
    ENOEXEC: 8,
    ENOLCK: 37,
    ENOLINK: 67,
    ENOMEM: 12,
    ENOMSG: 42,
    ENOPROTOOPT: 92,
    ENOSPC: 28,
    ENOSR: 63,
    ENOSTR: 60,
    ENOSYS: 38,
    ENOTCONN: 107,
    ENOTDIR: 20,
    ENOTEMPTY: 39,
    ENOTRECOVERABLE: 131,
    ENOTSOCK: 88,
    ENOTSUP: 95,
    ENOTTY: 25,
    ENXIO: 6,
    EOVERFLOW: 75,
    EOWNERDEAD: 130,
    EPERM: 1,
    EPIPE: 32,
    EPROTO: 71,
    EPROTONOSUPPORT: 93,
    EPROTOTYPE: 91,
    ERANGE: 34,
    EROFS: 30,
    ESPIPE: 29,
    ESRCH: 3,
    ESTALE: 116,
    ETIME: 62,
    ETIMEDOUT: 110,
    ETXTBSY: 26,
    EWOULDBLOCK: 11,
    EXDEV: 18,
  },
  $ERRNO_MESSAGES: {
    2: 'No such file or directory',
    13: 'Permission denied',
    98: 'Address already in use',
    99: 'Cannot assign requested address',
    97: 'Address family not supported by protocol',
    11: 'Resource temporarily unavailable',
    114: 'Operation already in progress',
    9: 'Bad file descriptor',
    74: 'Bad message',
    16: 'Device or resource busy',
    125: 'Operation canceled',
    10: 'No child processes',
    103: 'Software caused connection abort',
    111: 'Connection refused',
    104: 'Connection reset by peer',
    35: 'Resource deadlock avoided',
    89: 'Destination address required',
    33: 'Numerical argument out of domain',
    122: 'Disk quota exceeded',
    17: 'File exists',
    14: 'Bad address',
    27: 'File too large',
    113: 'No route to host',
    43: 'Identifier removed',
    84: 'Invalid or incomplete multibyte or wide character',
    115: 'Operation now in progress',
    4: 'Interrupted system call',
    22: 'Invalid argument',
    5: 'Input/output error',
    106: 'Transport endpoint is already connected',
    21: 'Is a directory',
    40: 'Too many levels of symbolic links',
    24: 'Too many open files',
    31: 'Too many links',
    90: 'Message too long',
    72: 'Multihop attempted',
    36: 'File name too long',
    100: 'Network is down',
    102: 'Network dropped connection on reset',
    101: 'Network is unreachable',
    23: 'Too many open files in system',
    105: 'No buffer space available',
    61: 'No data available',
    19: 'No such device',
    8: 'Exec format error',
    37: 'No locks available',
    67: 'Link has been severed',
    12: 'Cannot allocate memory',
    42: 'No message of desired type',
    92: 'Protocol not available',
    28: 'No space left on device',
    63: 'Out of streams resources',
    60: 'Device not a stream',
    38: 'Function not implemented',
    107: 'Transport endpoint is not connected',
    20: 'Not a directory',
    39: 'Directory not empty',
    131: 'State not recoverable',
    88: 'Socket operation on non-socket',
    95: 'Operation not supported',
    25: 'Inappropriate ioctl for device',
    6: 'No such device or address',
    75: 'Value too large for defined data type',
    130: 'Owner died',
    1: 'Operation not permitted',
    32: 'Broken pipe',
    71: 'Protocol error',
    93: 'Protocol not supported',
    91: 'Protocol wrong type for socket',
    34: 'Numerical result out of range',
    30: 'Read-only file system',
    29: 'Illegal seek',
    3: 'No such process',
    116: 'Stale NFS file handle',
    62: 'Timer expired',
    110: 'Connection timed out',
    26: 'Text file busy',
    18: 'Invalid cross-device link'
  },
  __setErrNo: function(value) {
    // For convenient setting and returning of errno.
    var me = ___setErrNo;
    if (!me.ptr) me.ptr = allocate([0], 'i32', ALLOC_NORMAL);
    {{{ makeSetValue('me.ptr', '0', 'value', 'i32') }}}
    return value;
  },
  __errno_location__deps: ['__setErrNo'],
  __errno_location: function() {
    if (!___setErrNo.ptr) ___setErrNo(0);
    return ___setErrNo.ptr;
  },

  // ==========================================================================
  // pthread.h (stubs for mutexes only - no thread support yet!)
  // ==========================================================================

  pthread_mutex_init: function() {},
  pthread_mutex_destroy: function() {},
  pthread_mutex_lock: function() {},
  pthread_mutex_unlock: function() {},

  // ==========================================================================
  // malloc.h
  // ==========================================================================

  memalign: function(boundary, size) {
    // leaks, and even returns an invalid pointer. Horrible hack... but then, this is a deprecated function...
    var ret = Runtime.staticAlloc(size + boundary);
    return ret + boundary - (ret % boundary);
  },

  posix_memalign__deps: ['memalign'],
  posix_memalign: function(memptr, alignment, size) {
    var ptr = _memalign(alignment, size);
    {{{ makeSetValue('memptr', '0', 'ptr', 'i8*') }}}
    return 0;
  },

  // ==========================================================================
  // emscripten.h
  // ==========================================================================

  emscripten_run_script: function(ptr) {
    eval(Pointer_stringify(ptr));
  },

  _Z21emscripten_run_scriptPKc: function(ptr) {
    eval(Pointer_stringify(ptr));
  }
};