The Tor Browser: memory/build/replace_malloc.h@ca08bd8f51b2 (annotated)

memory/build/replace_malloc.h@ca08bd8f51b2 (annotated)

memory/build/replace_malloc.h

Wed, 31 Dec 2014 06:55:46 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:55:46 +0100
changeset 1: ca08bd8f51b2
permissions: -rw-r--r--

Added tag TORBROWSER_REPLICA for changeset 6474c204b198

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef replace_malloc_h
 #define replace_malloc_h
 /*
  * The replace_malloc facility allows an external library to replace or
  * supplement the jemalloc implementation.
  *
  * The external library may be hooked by setting one of the following
  * environment variables to the library path:
  *   - LD_PRELOAD on Linux,
  *   - DYLD_INSERT_LIBRARIES on OSX,
  *   - MOZ_REPLACE_MALLOC_LIB on Windows and Android.
  *
  * An initialization function is called before any malloc replacement
  * function, and has the following declaration:
  *
  *   void replace_init(const malloc_table_t *)
  *
  * The const malloc_table_t pointer given to that function is a table
  * containing pointers to the original jemalloc implementation, so that
  * replacement functions can call them back if they need to. The pointer
  * itself can safely be kept around (no need to copy the table itself).
  *
  * The functions to be implemented in the external library are of the form:
  *
  *   void *replace_malloc(size_t size)
  *   {
  *     // Fiddle with the size if necessary.
  *     // orig->malloc doesn't have to be called if the external library
  *     // provides its own allocator, but in this case it will have to
  *     // implement all functions.
  *     void *ptr = orig->malloc(size);
  *     // Do whatever you want with the ptr.
  *     return ptr;
  *   }
  *
  * where "orig" is the pointer obtained from replace_init.
  *
  * See malloc_decls.h for a list of functions that can be replaced this
  * way. The implementations are all in the form:
  *   return_type replace_name(arguments [,...])
  *
  * They don't all need to be provided.
  *
  * Building a replace-malloc library is like rocket science. It can end up
  * with things blowing up, especially when trying to use complex types, and
  * even more especially when these types come from XPCOM or other parts of the
  * Mozilla codebase.
  * It is recommended to add the following to a replace-malloc implementation's
  * Makefile.in:
  *   MOZ_GLUE_LDFLAGS = # Don't link against mozglue
  *   WRAP_LDFLAGS = # Never wrap malloc function calls with -Wl,--wrap
  * and the following to the implementation's moz.build:
  *   DISABLE_STL_WRAPPING = True # Avoid STL wrapping
  *
  * If your replace-malloc implementation lives under memory/replace, these
  * are taken care of by memory/replace/defs.mk.
  */
 /* Implementing a replace-malloc library is incompatible with using mozalloc. */
 #define MOZ_NO_MOZALLOC 1
 #include "mozilla/Types.h"
 MOZ_BEGIN_EXTERN_C
 #define MALLOC_DECL(name, return_type, ...) \
   typedef return_type(name ## _impl_t)(__VA_ARGS__);
 #include "malloc_decls.h"
 #define MALLOC_DECL(name, return_type, ...) \
   name ## _impl_t * name;
 typedef struct {
 #include "malloc_decls.h"
 } malloc_table_t;
 /* MOZ_NO_REPLACE_FUNC_DECL and MOZ_REPLACE_WEAK are only defined in
  * replace_malloc.c. Normally including this header will add function
  * definitions. */
 #ifndef MOZ_NO_REPLACE_FUNC_DECL
 #  ifndef MOZ_REPLACE_WEAK
 #    define MOZ_REPLACE_WEAK
 #  endif
 #  define MALLOC_DECL(name, return_type, ...) \
     MOZ_EXPORT return_type replace_ ## name(__VA_ARGS__) MOZ_REPLACE_WEAK;
 #  define MALLOC_FUNCS MALLOC_FUNCS_ALL
 #  include "malloc_decls.h"
 #endif /* MOZ_NO_REPLACE_FUNC_DECL */
 /*
  * posix_memalign, aligned_alloc, memalign and valloc all implement some
  * kind of aligned memory allocation. For convenience, replace_posix_memalign,
  * replace_aligned_alloc and replace_valloc can be automatically derived from
  * memalign when MOZ_REPLACE_ONLY_MEMALIGN is defined before including this
  * header. PAGE_SIZE also needs to be defined to the appropriate expression.
  */
 #ifdef MOZ_REPLACE_ONLY_MEMALIGN
 #include <errno.h>
 int replace_posix_memalign(void **ptr, size_t alignment, size_t size)
 {
   if (size == 0) {
     *ptr = NULL;
     return 0;
   }
   /* alignment must be a power of two and a multiple of sizeof(void *) */
   if (((alignment - 1) & alignment) != 0 || (alignment % sizeof(void *)))
     return EINVAL;
   *ptr = replace_memalign(alignment, size);
   return *ptr ? 0 : ENOMEM;
 }
 void *replace_aligned_alloc(size_t alignment, size_t size)
 {
   /* size should be a multiple of alignment */
   if (size % alignment)
     return NULL;
   return replace_memalign(alignment, size);
 }
 void *replace_valloc(size_t size)
 {
   return replace_memalign(PAGE_SIZE, size);
 }
 #endif
 MOZ_END_EXTERN_C
 #endif /* replace_malloc_h */

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memory/build/replace_malloc.h@ca08bd8f51b2 (annotated)

memory/build/replace_malloc.h