| 1 | /* |
| 2 | * Copyright (C) 2009 Pierre-Marc Fournier |
| 3 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 4 | * |
| 5 | * This library is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU Lesser General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2.1 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This library is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * Lesser General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU Lesser General Public |
| 16 | * License along with this library; if not, write to the Free Software |
| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | */ |
| 19 | |
| 20 | #define _GNU_SOURCE |
| 21 | #include <dlfcn.h> |
| 22 | #include <sys/types.h> |
| 23 | #include <stdio.h> |
| 24 | #include <urcu/system.h> |
| 25 | #include <urcu/uatomic.h> |
| 26 | |
| 27 | #define TRACEPOINT_DEFINE |
| 28 | #define TRACEPOINT_CREATE_PROBES |
| 29 | #include "ust_libc.h" |
| 30 | |
| 31 | #define STATIC_CALLOC_LEN 4096 |
| 32 | static char static_calloc_buf[STATIC_CALLOC_LEN]; |
| 33 | static unsigned long static_calloc_buf_offset; |
| 34 | |
| 35 | static void *static_calloc(size_t nmemb, size_t size) |
| 36 | { |
| 37 | unsigned long prev_offset, new_offset, res_offset; |
| 38 | |
| 39 | /* |
| 40 | * Protect static_calloc_buf_offset from concurrent updates |
| 41 | * using a cmpxchg loop rather than a mutex to remove a |
| 42 | * dependency on pthread. This will minimize the risk of bad |
| 43 | * interaction between mutex and malloc instrumentation. |
| 44 | */ |
| 45 | res_offset = CMM_LOAD_SHARED(static_calloc_buf_offset); |
| 46 | do { |
| 47 | prev_offset = res_offset; |
| 48 | if (nmemb * size > sizeof(static_calloc_buf) - prev_offset) { |
| 49 | return NULL; |
| 50 | } |
| 51 | new_offset = prev_offset + nmemb * size; |
| 52 | } while ((res_offset = uatomic_cmpxchg(&static_calloc_buf_offset, |
| 53 | prev_offset, new_offset)) != prev_offset); |
| 54 | return &static_calloc_buf[prev_offset]; |
| 55 | } |
| 56 | |
| 57 | void *malloc(size_t size) |
| 58 | { |
| 59 | static void *(*plibc_malloc)(size_t size); |
| 60 | void *retval; |
| 61 | |
| 62 | if (plibc_malloc == NULL) { |
| 63 | plibc_malloc = dlsym(RTLD_NEXT, "malloc"); |
| 64 | if (plibc_malloc == NULL) { |
| 65 | fprintf(stderr, "mallocwrap: unable to find malloc\n"); |
| 66 | return NULL; |
| 67 | } |
| 68 | } |
| 69 | retval = plibc_malloc(size); |
| 70 | tracepoint(ust_libc, malloc, size, retval); |
| 71 | return retval; |
| 72 | } |
| 73 | |
| 74 | void free(void *ptr) |
| 75 | { |
| 76 | static void (*plibc_free)(void *ptr); |
| 77 | |
| 78 | /* Check whether the memory was allocated with |
| 79 | * static_calloc, in which case there is nothing |
| 80 | * to free. |
| 81 | */ |
| 82 | if ((char *)ptr >= static_calloc_buf && |
| 83 | (char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN) { |
| 84 | return; |
| 85 | } |
| 86 | |
| 87 | if (plibc_free == NULL) { |
| 88 | plibc_free = dlsym(RTLD_NEXT, "free"); |
| 89 | if (plibc_free == NULL) { |
| 90 | fprintf(stderr, "mallocwrap: unable to find free\n"); |
| 91 | return; |
| 92 | } |
| 93 | } |
| 94 | tracepoint(ust_libc, free, ptr); |
| 95 | plibc_free(ptr); |
| 96 | } |
| 97 | |
| 98 | void *calloc(size_t nmemb, size_t size) |
| 99 | { |
| 100 | static void *(*volatile plibc_calloc)(size_t nmemb, size_t size); |
| 101 | void *retval; |
| 102 | |
| 103 | if (plibc_calloc == NULL) { |
| 104 | /* |
| 105 | * Temporarily redirect to static_calloc, |
| 106 | * until the dlsym lookup has completed. |
| 107 | */ |
| 108 | plibc_calloc = static_calloc; |
| 109 | plibc_calloc = dlsym(RTLD_NEXT, "calloc"); |
| 110 | if (plibc_calloc == NULL) { |
| 111 | fprintf(stderr, "callocwrap: unable to find calloc\n"); |
| 112 | return NULL; |
| 113 | } |
| 114 | } |
| 115 | retval = plibc_calloc(nmemb, size); |
| 116 | tracepoint(ust_libc, calloc, nmemb, size, retval); |
| 117 | return retval; |
| 118 | } |
| 119 | |
| 120 | void *realloc(void *ptr, size_t size) |
| 121 | { |
| 122 | static void *(*plibc_realloc)(void *ptr, size_t size); |
| 123 | void *retval; |
| 124 | |
| 125 | if (plibc_realloc == NULL) { |
| 126 | plibc_realloc = dlsym(RTLD_NEXT, "realloc"); |
| 127 | if (plibc_realloc == NULL) { |
| 128 | fprintf(stderr, "reallocwrap: unable to find realloc\n"); |
| 129 | return NULL; |
| 130 | } |
| 131 | } |
| 132 | retval = plibc_realloc(ptr, size); |
| 133 | tracepoint(ust_libc, realloc, ptr, size, retval); |
| 134 | return retval; |
| 135 | } |
| 136 | |
| 137 | void *memalign(size_t alignment, size_t size) |
| 138 | { |
| 139 | static void *(*plibc_memalign)(size_t alignment, size_t size); |
| 140 | void *retval; |
| 141 | |
| 142 | if (plibc_memalign == NULL) { |
| 143 | plibc_memalign = dlsym(RTLD_NEXT, "memalign"); |
| 144 | if (plibc_memalign == NULL) { |
| 145 | fprintf(stderr, "memalignwrap: unable to find memalign\n"); |
| 146 | return NULL; |
| 147 | } |
| 148 | } |
| 149 | retval = plibc_memalign(alignment, size); |
| 150 | tracepoint(ust_libc, memalign, alignment, size, retval); |
| 151 | return retval; |
| 152 | } |
| 153 | |
| 154 | int posix_memalign(void **memptr, size_t alignment, size_t size) |
| 155 | { |
| 156 | static int(*plibc_posix_memalign)(void **memptr, size_t alignment, size_t size); |
| 157 | int retval; |
| 158 | |
| 159 | if (plibc_posix_memalign == NULL) { |
| 160 | plibc_posix_memalign = dlsym(RTLD_NEXT, "posix_memalign"); |
| 161 | if (plibc_posix_memalign == NULL) { |
| 162 | fprintf(stderr, "posix_memalignwrap: unable to find posix_memalign\n"); |
| 163 | return ENOMEM; |
| 164 | } |
| 165 | } |
| 166 | retval = plibc_posix_memalign(memptr, alignment, size); |
| 167 | tracepoint(ust_libc, posix_memalign, *memptr, alignment, size, retval); |
| 168 | return retval; |
| 169 | } |