1 /* Copyright (c) 2010-2019. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
7 /* Redefine the classical malloc/free/realloc functions so that they fit well in the mmalloc framework */
14 #include "mmprivate.h"
15 #include "src/internal_config.h"
16 #include "src/mc/mc_base.h"
17 #include "src/mc/remote/mc_protocol.h"
18 #include "src/xbt_modinter.h"
21 /* ***** Whether to use `mmalloc` of the underlying malloc ***** */
23 static int __malloc_use_mmalloc;
25 int malloc_use_mmalloc(void)
27 return __malloc_use_mmalloc;
30 /* ***** Current heap ***** */
32 /* The mmalloc() package can use a single implicit malloc descriptor
33 for mmalloc/mrealloc/mfree operations which do not supply an explicit
34 descriptor. This allows mmalloc() to provide
35 backwards compatibility with the non-mmap'd version. */
36 xbt_mheap_t __mmalloc_default_mdp = NULL;
38 /* The heap we are currently using. */
39 static xbt_mheap_t __mmalloc_current_heap = NULL;
41 xbt_mheap_t mmalloc_get_current_heap(void)
43 return __mmalloc_current_heap;
46 /* Override the malloc-like functions if MC is activated at compile time */
49 /* ***** Temporary allocator
51 * This is used before we have found the real malloc implementation with dlsym.
54 #ifdef __FreeBSD__ /* FreeBSD require more memory, other might */
55 # define BUFFER_SIZE 256
56 #else /* Valid on: Linux */
57 # define BUFFER_SIZE 32
59 static size_t fake_alloc_index;
60 static uint64_t buffer[BUFFER_SIZE];
62 /* Fake implementations, they are used to fool dlsym:
63 * dlsym used calloc and falls back to some other mechanism
66 static void* mm_fake_malloc(size_t n)
68 // How many uint64_t do w need?
69 size_t count = n / sizeof(uint64_t);
70 if (n % sizeof(uint64_t))
72 // Check that we have enough available memory:
73 if (fake_alloc_index + count >= BUFFER_SIZE)
76 uint64_t* res = buffer + fake_alloc_index;
77 fake_alloc_index += count;
81 static void* mm_fake_calloc(size_t nmemb, size_t size)
83 // This is fresh .bss data, we don't need to clear it:
84 size_t n = nmemb * size;
85 return mm_fake_malloc(n);
88 static void* mm_fake_realloc(XBT_ATTRIB_UNUSED void* p, size_t s)
90 return mm_fake_malloc(s);
93 static void mm_fake_free(XBT_ATTRIB_UNUSED void* p)
98 /* Function signatures for the main malloc functions: */
99 typedef void* (*mm_malloc_t)(size_t size);
100 typedef void (*mm_free_t)(void*);
101 typedef void* (*mm_calloc_t)(size_t nmemb, size_t size);
102 typedef void* (*mm_realloc_t)(void *ptr, size_t size);
104 /* Function pointers to the real/next implementations: */
105 static mm_malloc_t mm_real_malloc;
106 static mm_free_t mm_real_free;
107 static mm_calloc_t mm_real_calloc;
108 static mm_realloc_t mm_real_realloc;
110 static int mm_initializing;
111 static int mm_initialized;
113 /** Constructor functions used to initialize the malloc implementation
115 XBT_ATTRIB_CONSTRUCTOR(101) static void mm_legacy_constructor()
120 __malloc_use_mmalloc = getenv(MC_ENV_VARIABLE) ? 1 : 0;
121 if (__malloc_use_mmalloc) {
122 __mmalloc_current_heap = mmalloc_preinit();
125 mm_real_realloc = (void *(*)(void *, size_t))dlfunc(RTLD_NEXT, "realloc");
126 mm_real_malloc = (void *(*)(size_t))dlfunc(RTLD_NEXT, "malloc");
127 mm_real_free = (void (*)(void *))dlfunc(RTLD_NEXT, "free");
128 mm_real_calloc = (void *(*)(size_t, size_t))dlfunc(RTLD_NEXT, "calloc");
130 mm_real_realloc = dlsym(RTLD_NEXT, "realloc");
131 mm_real_malloc = dlsym(RTLD_NEXT, "malloc");
132 mm_real_free = dlsym(RTLD_NEXT, "free");
133 mm_real_calloc = dlsym(RTLD_NEXT, "calloc");
140 /* ***** malloc/free implementation
142 * They call either the underlying/native/RTLD_NEXT implementation (non MC mode)
143 * or the mm implementation (MC mode).
145 * If we are initializing the malloc subsystem, we call the fake/dummy `malloc`
146 * implementation. This is necessary because `dlsym` calls `malloc` and friends.
149 #define GET_HEAP() __mmalloc_current_heap
151 void *malloc(size_t n)
153 if (!mm_initialized) {
155 return mm_fake_malloc(n);
156 mm_legacy_constructor();
159 if (!__malloc_use_mmalloc) {
160 return mm_real_malloc(n);
163 xbt_mheap_t mdp = GET_HEAP();
168 void *ret = mmalloc(mdp, n);
173 void *calloc(size_t nmemb, size_t size)
175 if (!mm_initialized) {
177 return mm_fake_calloc(nmemb, size);
178 mm_legacy_constructor();
181 if (!__malloc_use_mmalloc) {
182 return mm_real_calloc(nmemb, size);
185 xbt_mheap_t mdp = GET_HEAP();
190 void *ret = mmalloc(mdp, nmemb*size);
192 // This was already done in the callee:
193 if(!(mdp->options & XBT_MHEAP_OPTION_MEMSET)) {
194 memset(ret, 0, nmemb * size);
199 void *realloc(void *p, size_t s)
201 if (!mm_initialized) {
203 return mm_fake_realloc(p, s);
204 mm_legacy_constructor();
207 if (!__malloc_use_mmalloc) {
208 return mm_real_realloc(p, s);
211 xbt_mheap_t mdp = GET_HEAP();
216 void* ret = mrealloc(mdp, p, s);
223 if (!mm_initialized) {
225 return mm_fake_free(p);
226 mm_legacy_constructor();
229 if (!__malloc_use_mmalloc) {
237 xbt_mheap_t mdp = GET_HEAP();
242 #endif /* SIMGRID_HAVE_MC */