1// Copyright (c) 2011, Google Inc.
2// All rights reserved.
3//
4// Redistribution and use in source and binary forms, with or without
5// modification, are permitted provided that the following conditions are
6// met:
7//
8//     * Redistributions of source code must retain the above copyright
9// notice, this list of conditions and the following disclaimer.
10//     * Redistributions in binary form must reproduce the above
11// copyright notice, this list of conditions and the following disclaimer
12// in the documentation and/or other materials provided with the
13// distribution.
14//     * Neither the name of Google Inc. nor the names of its
15// contributors may be used to endorse or promote products derived from
16// this software without specific prior written permission.
17//
18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30// ---
31// Author: Craig Silverstein <opensource@google.com>
32//
33// Used to override malloc routines on systems that are using glibc.
34
35#ifndef TCMALLOC_LIBC_OVERRIDE_GLIBC_INL_H_
36#define TCMALLOC_LIBC_OVERRIDE_GLIBC_INL_H_
37
38// MALLOC_HOOK_MAYBE_VOLATILE is defined at config.h in the original gperftools.
39// Chromium does this check with the macro __MALLOC_HOOK_VOLATILE.
40// GLibc 2.14+ requires the hook functions be declared volatile, based on the
41// value of the define __MALLOC_HOOK_VOLATILE. For compatibility with
42// older/non-GLibc implementations, provide an empty definition.
43#if !defined(__MALLOC_HOOK_VOLATILE)
44#define MALLOC_HOOK_MAYBE_VOLATILE /**/
45#else
46#define MALLOC_HOOK_MAYBE_VOLATILE __MALLOC_HOOK_VOLATILE
47#endif
48
49#include <config.h>
50#include <features.h>     // for __GLIBC__
51#ifdef HAVE_SYS_CDEFS_H
52#include <sys/cdefs.h>    // for __THROW
53#endif
54#include <gperftools/tcmalloc.h>
55
56#ifndef __GLIBC__
57# error libc_override_glibc.h is for glibc distributions only.
58#endif
59
60// In glibc, the memory-allocation methods are weak symbols, so we can
61// just override them with our own.  If we're using gcc, we can use
62// __attribute__((alias)) to do the overriding easily (exception:
63// Mach-O, which doesn't support aliases).  Otherwise we have to use a
64// function call.
65#if !defined(__GNUC__) || defined(__MACH__)
66
67// This also defines ReplaceSystemAlloc().
68# include "libc_override_redefine.h"  // defines functions malloc()/etc
69
70#else  // #if !defined(__GNUC__) || defined(__MACH__)
71
72// If we get here, we're a gcc system, so do all the overriding we do
73// with gcc.  This does the overriding of all the 'normal' memory
74// allocation.  This also defines ReplaceSystemAlloc().
75# include "libc_override_gcc_and_weak.h"
76
77// We also have to do some glibc-specific overriding.  Some library
78// routines on RedHat 9 allocate memory using malloc() and free it
79// using __libc_free() (or vice-versa).  Since we provide our own
80// implementations of malloc/free, we need to make sure that the
81// __libc_XXX variants (defined as part of glibc) also point to the
82// same implementations.  Since it only matters for redhat, we
83// do it inside the gcc #ifdef, since redhat uses gcc.
84// TODO(csilvers): only do this if we detect we're an old enough glibc?
85
86#define ALIAS(tc_fn)   __attribute__ ((alias (#tc_fn)))
87extern "C" {
88  void* __libc_malloc(size_t size)                ALIAS(tc_malloc);
89  void __libc_free(void* ptr)                     ALIAS(tc_free);
90  void* __libc_realloc(void* ptr, size_t size)    ALIAS(tc_realloc);
91  void* __libc_calloc(size_t n, size_t size)      ALIAS(tc_calloc);
92  void __libc_cfree(void* ptr)                    ALIAS(tc_cfree);
93  void* __libc_memalign(size_t align, size_t s)   ALIAS(tc_memalign);
94  void* __libc_valloc(size_t size)                ALIAS(tc_valloc);
95  void* __libc_pvalloc(size_t size)               ALIAS(tc_pvalloc);
96  int __posix_memalign(void** r, size_t a, size_t s)  ALIAS(tc_posix_memalign);
97}   // extern "C"
98#undef ALIAS
99
100#endif  // #if defined(__GNUC__) && !defined(__MACH__)
101
102
103// We also have to hook libc malloc.  While our work with weak symbols
104// should make sure libc malloc is never called in most situations, it
105// can be worked around by shared libraries with the DEEPBIND
106// environment variable set.  The below hooks libc to call our malloc
107// routines even in that situation.  In other situations, this hook
108// should never be called.
109extern "C" {
110static void* glibc_override_malloc(size_t size, const void *caller) {
111  return tc_malloc(size);
112}
113static void* glibc_override_realloc(void *ptr, size_t size,
114                                    const void *caller) {
115  return tc_realloc(ptr, size);
116}
117static void glibc_override_free(void *ptr, const void *caller) {
118  tc_free(ptr);
119}
120static void* glibc_override_memalign(size_t align, size_t size,
121                                     const void *caller) {
122  return tc_memalign(align, size);
123}
124
125// We should be using __malloc_initialize_hook here, like the #if 0
126// code below.  (See http://swoolley.org/man.cgi/3/malloc_hook.)
127// However, this causes weird linker errors with programs that link
128// with -static, so instead we just assign the vars directly at
129// static-constructor time.  That should serve the same effect of
130// making sure the hooks are set before the first malloc call the
131// program makes.
132#if 0
133#include <malloc.h>  // for __malloc_hook, etc.
134void glibc_override_malloc_init_hook(void) {
135  __malloc_hook = glibc_override_malloc;
136  __realloc_hook = glibc_override_realloc;
137  __free_hook = glibc_override_free;
138  __memalign_hook = glibc_override_memalign;
139}
140
141void (* MALLOC_HOOK_MAYBE_VOLATILE __malloc_initialize_hook)(void)
142    = &glibc_override_malloc_init_hook;
143#endif
144
145void* (* MALLOC_HOOK_MAYBE_VOLATILE __malloc_hook)(size_t, const void*)
146    = &glibc_override_malloc;
147void* (* MALLOC_HOOK_MAYBE_VOLATILE __realloc_hook)(void*, size_t, const void*)
148    = &glibc_override_realloc;
149void (* MALLOC_HOOK_MAYBE_VOLATILE __free_hook)(void*, const void*)
150    = &glibc_override_free;
151void* (* MALLOC_HOOK_MAYBE_VOLATILE __memalign_hook)(size_t,size_t, const void*)
152    = &glibc_override_memalign;
153
154}   // extern "C"
155
156// No need to write ReplaceSystemAlloc(); one of the #includes above
157// did it for us.
158
159#endif  // TCMALLOC_LIBC_OVERRIDE_GLIBC_INL_H_
160