my_malloc.c

/* Copyright (c) 2000, 2023, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   Without limiting anything contained in the foregoing, this file,
   which is part of C Driver for MySQL (Connector/C), is also subject to the
   Universal FOSS Exception, version 1.0, a copy of which can be found at
   http://oss.oracle.com/licenses/universal-foss-exception.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include "mysys_priv.h"
#include "my_sys.h"
#include "mysys_err.h"
#include <m_string.h>
#include "my_thread_local.h"

#ifdef HAVE_PSI_MEMORY_INTERFACE
#define USE_MALLOC_WRAPPER
#endif

static void *my_raw_malloc(size_t size, myf my_flags);
static void my_raw_free(void *ptr);

#ifdef USE_MALLOC_WRAPPER
struct my_memory_header
{
  PSI_memory_key m_key;
  uint m_magic;
  size_t m_size;
  PSI_thread *m_owner;
};
typedef struct my_memory_header my_memory_header;
#define HEADER_SIZE 32

#define MAGIC 1234

#define USER_TO_HEADER(P) \
  ( (my_memory_header*) (((char *) P) - HEADER_SIZE ))
#define HEADER_TO_USER(P) \
  ( ((char*) P) + HEADER_SIZE )

void * my_malloc(PSI_memory_key key, size_t size, myf flags)
{
  my_memory_header *mh;
  size_t raw_size;
  compile_time_assert(sizeof(my_memory_header) <= HEADER_SIZE);

  raw_size= HEADER_SIZE + size;
  mh= (my_memory_header*) my_raw_malloc(raw_size, flags);
  if (likely(mh != NULL))
  {
    void *user_ptr;
    mh->m_magic= MAGIC;
    mh->m_size= size;
    mh->m_key= PSI_MEMORY_CALL(memory_alloc)(key, size, & mh->m_owner);
    user_ptr= HEADER_TO_USER(mh);
    MEM_MALLOCLIKE_BLOCK(user_ptr, size, 0, (flags & MY_ZEROFILL));
    return user_ptr;
  }
  return NULL;
}

void *
my_realloc(PSI_memory_key key, void *ptr, size_t size, myf flags)
{
  my_memory_header *old_mh;
  size_t old_size;
  size_t min_size;
  void *new_ptr;

  if (ptr == NULL)
    return my_malloc(key, size, flags);

  old_mh= USER_TO_HEADER(ptr);
  assert((old_mh->m_key == key) || (old_mh->m_key == PSI_NOT_INSTRUMENTED));
  assert(old_mh->m_magic == MAGIC);

  old_size= old_mh->m_size;

  if (old_size == size)
    return ptr;

  new_ptr= my_malloc(key, size, flags);
  if (likely(new_ptr != NULL))
  {
#ifndef NDEBUG
    my_memory_header *new_mh= USER_TO_HEADER(new_ptr);
#endif

    assert((new_mh->m_key == key) || (new_mh->m_key == PSI_NOT_INSTRUMENTED));
    assert(new_mh->m_magic == MAGIC);
    assert(new_mh->m_size == size);

    min_size= (old_size < size) ? old_size : size;
    memcpy(new_ptr, ptr, min_size);
    my_free(ptr);

    return new_ptr;
  }
  return NULL;
}

void my_claim(void *ptr)
{
  my_memory_header *mh;

  if (ptr == NULL)
    return;

  mh= USER_TO_HEADER(ptr);
  assert(mh->m_magic == MAGIC);
  mh->m_key= PSI_MEMORY_CALL(memory_claim)(mh->m_key, mh->m_size, & mh->m_owner);
}

void my_free(void *ptr)
{
  my_memory_header *mh;

  if (ptr == NULL)
    return;

  mh= USER_TO_HEADER(ptr);
  assert(mh->m_magic == MAGIC);
  PSI_MEMORY_CALL(memory_free)(mh->m_key, mh->m_size, mh->m_owner);
  /* Catch double free */
  mh->m_magic= 0xDEAD;
  MEM_FREELIKE_BLOCK(ptr, 0);
  my_raw_free(mh);
}

#else

void *my_malloc(PSI_memory_key key MY_ATTRIBUTE((unused)),
                size_t size, myf my_flags)
{
  return my_raw_malloc(size, my_flags);
}

static void *my_raw_realloc(void *oldpoint, size_t size, myf my_flags);

void *my_realloc(PSI_memory_key key MY_ATTRIBUTE((unused)),
                 void *ptr, size_t size, myf flags)
{
  return my_raw_realloc(ptr, size, flags);
}

void my_claim(void *ptr MY_ATTRIBUTE((unused)))
{
  /* Empty */
}

void my_free(void *ptr)
{
  my_raw_free(ptr);
}
#endif


/**
  Allocate a sized block of memory.

  @param size   The size of the memory block in bytes.
  @param flags  Failure action modifiers (bitmasks).

  @return A pointer to the allocated memory block, or NULL on failure.
*/
static void *my_raw_malloc(size_t size, myf my_flags)
{
  void* point;
  DBUG_ENTER("my_raw_malloc");
  DBUG_PRINT("my",("size: %lu  my_flags: %d", (ulong) size, my_flags));

  /* Safety */
  if (!size)
    size=1;

#if defined(MY_MSCRT_DEBUG)
  if (my_flags & MY_ZEROFILL)
    point= _calloc_dbg(size, 1, _CLIENT_BLOCK, __FILE__, __LINE__);
  else
    point= _malloc_dbg(size, _CLIENT_BLOCK, __FILE__, __LINE__);
#else
  if (my_flags & MY_ZEROFILL)
    point= calloc(size, 1);
  else
    point= malloc(size);
#endif

  DBUG_EXECUTE_IF("simulate_out_of_memory",
                  {
                    free(point);
                    point= NULL;
                  });
  DBUG_EXECUTE_IF("simulate_persistent_out_of_memory",
                  {
                    free(point);
                    point= NULL;
                  });

  if (point == NULL)
  {
    set_my_errno(errno);
    if (my_flags & MY_FAE)
      error_handler_hook=fatal_error_handler_hook;
    if (my_flags & (MY_FAE+MY_WME))
      my_error(EE_OUTOFMEMORY, MYF(ME_ERRORLOG + ME_FATALERROR),size);
    DBUG_EXECUTE_IF("simulate_out_of_memory",
                    DBUG_SET("-d,simulate_out_of_memory"););
    if (my_flags & MY_FAE)
      exit(1);
  }

  DBUG_PRINT("exit",("ptr: %p", point));
  DBUG_RETURN(point);
}


#ifndef USE_MALLOC_WRAPPER
/**
   @brief wrapper around realloc()

   @param  oldpoint        pointer to currently allocated area
   @param  size            new size requested, must be >0
   @param  my_flags        flags

   @note if size==0 realloc() may return NULL; my_realloc() treats this as an
   error which is not the intention of realloc()
*/
static void *my_raw_realloc(void *oldpoint, size_t size, myf my_flags)
{
  void *point;
  DBUG_ENTER("my_realloc");
  DBUG_PRINT("my",("ptr: %p  size: %lu  my_flags: %d", oldpoint,
                   (ulong) size, my_flags));

  assert(size > 0);
  /* These flags are mutually exclusive. */
  assert(!((my_flags & MY_FREE_ON_ERROR) &&
           (my_flags & MY_HOLD_ON_ERROR)));
  DBUG_EXECUTE_IF("simulate_out_of_memory",
                  point= NULL;
                  goto end;);
  if (!oldpoint && (my_flags & MY_ALLOW_ZERO_PTR))
    DBUG_RETURN(my_raw_malloc(size, my_flags));
#if defined(MY_MSCRT_DEBUG)
  point= _realloc_dbg(oldpoint, size, _CLIENT_BLOCK, __FILE__, __LINE__);
#else
  point= realloc(oldpoint, size);
#endif
#ifndef NDEBUG
end:
#endif
  if (point == NULL)
  {
    if (my_flags & MY_HOLD_ON_ERROR)
      DBUG_RETURN(oldpoint);
    if (my_flags & MY_FREE_ON_ERROR)
      my_free(oldpoint);
    set_my_errno(errno);
    if (my_flags & (MY_FAE+MY_WME))
      my_error(EE_OUTOFMEMORY, MYF(ME_FATALERROR),
               size);
    DBUG_EXECUTE_IF("simulate_out_of_memory",
                    DBUG_SET("-d,simulate_out_of_memory"););
  }
  DBUG_PRINT("exit",("ptr: %p", point));
  DBUG_RETURN(point);
}
#endif

/**
  Free memory allocated with my_raw_malloc.

  @remark Relies on free being able to handle a NULL argument.

  @param ptr Pointer to the memory allocated by my_raw_malloc.
*/
static void my_raw_free(void *ptr)
{
  DBUG_ENTER("my_free");
  DBUG_PRINT("my",("ptr: %p", ptr));
#if defined(MY_MSCRT_DEBUG)
  _free_dbg(ptr, _CLIENT_BLOCK);
#else
  free(ptr);
#endif
  DBUG_VOID_RETURN;
}


void *my_memdup(PSI_memory_key key, const void *from, size_t length, myf my_flags)
{
  void *ptr;
  if ((ptr= my_malloc(key, length, my_flags)) != 0)
    memcpy(ptr, from, length);
  return ptr;
}


char *my_strdup(PSI_memory_key key, const char *from, myf my_flags)
{
  char *ptr;
  size_t length= strlen(from)+1;
  if ((ptr= (char*) my_malloc(key, length, my_flags)))
    memcpy(ptr, from, length);
  return ptr;
}


char *my_strndup(PSI_memory_key key, const char *from, size_t length, myf my_flags)
{
  char *ptr;
  if ((ptr= (char*) my_malloc(key, length+1, my_flags)))
  {
    memcpy(ptr, from, length);
    ptr[length]= 0;
  }
  return ptr;
}