lib/leak-checker.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include "leak-checker.h"
  19 #include <inttypes.h>
  20 #include "backtrace.h"
  21 #include "vlog.h"
  22
  23 VLOG_DEFINE_THIS_MODULE(leak_checker);
  24
  25 #ifndef HAVE_MALLOC_HOOKS
  26 void
  27 leak_checker_start(const char *file_name OVS_UNUSED)
  28 {
  29     VLOG_WARN("not enabling leak checker because the libc in use does not "
  30               "have the required hooks");
  31 }
  32
  33 void
  34 leak_checker_set_limit(off_t max_size OVS_UNUSED)
  35 {
  36 }
  37
  38 void
  39 leak_checker_claim(const void *p OVS_UNUSED)
  40 {
  41 }
  42
  43 void
  44 leak_checker_usage(void)
  45 {
  46     printf("  --check-leaks=FILE      (accepted but ignored in this build)\n");
  47 }
  48 #else /* HAVE_MALLOC_HOOKS */
  49 #include <errno.h>
  50 #include <fcntl.h>
  51 #include <malloc.h>
  52 #include <sys/stat.h>
  53
  54 typedef void *malloc_hook_type(size_t, const void *);
  55 typedef void *realloc_hook_type(void *, size_t, const void *);
  56 typedef void free_hook_type(void *, const void *);
  57
  58 struct hooks {
  59     malloc_hook_type *malloc_hook_func;
  60     realloc_hook_type *realloc_hook_func;
  61     free_hook_type *free_hook_func;
  62 };
  63
  64 static malloc_hook_type hook_malloc;
  65 static realloc_hook_type hook_realloc;
  66 static free_hook_type hook_free;
  67
  68 static struct hooks libc_hooks;
  69 static const struct hooks our_hooks = { hook_malloc, hook_realloc, hook_free };
  70
  71 static FILE *file;
  72 static off_t limit = 10 * 1000 * 1000;
  73
  74 static void
  75 get_hooks(struct hooks *hooks)
  76 {
  77     hooks->malloc_hook_func = __malloc_hook;
  78     hooks->realloc_hook_func = __realloc_hook;
  79     hooks->free_hook_func = __free_hook;
  80 }
  81
  82 static void
  83 set_hooks(const struct hooks *hooks)
  84 {
  85     __malloc_hook = hooks->malloc_hook_func;
  86     __realloc_hook = hooks->realloc_hook_func;
  87     __free_hook = hooks->free_hook_func;
  88 }
  89
  90 void
  91 leak_checker_start(const char *file_name)
  92 {
  93     if (!file) {
  94         file = fopen(file_name, "w");
  95         if (!file) {
  96             VLOG_WARN("failed to create \"%s\": %s",
  97                       file_name, strerror(errno));
  98             return;
  99         }
 100         setvbuf(file, NULL, _IOLBF, 0);
 101         VLOG_WARN("enabled memory leak logging to \"%s\"", file_name);
 102         get_hooks(&libc_hooks);
 103         set_hooks(&our_hooks);
 104     }
 105 }
 106
 107 void
 108 leak_checker_stop(void)
 109 {
 110     if (file) {
 111         fclose(file);
 112         file = NULL;
 113         set_hooks(&libc_hooks);
 114         VLOG_WARN("disabled memory leak logging");
 115     }
 116 }
 117
 118 void
 119 leak_checker_set_limit(off_t limit_)
 120 {
 121     limit = limit_;
 122 }
 123
 124 void
 125 leak_checker_usage(void)
 126 {
 127     printf("  --check-leaks=FILE      log malloc and free calls to FILE\n");
 128 }
 129
 130 static void PRINTF_FORMAT(1, 2)
 131 log_callers(const char *format, ...)
 132 {
 133     struct backtrace backtrace;
 134     va_list args;
 135     int i;
 136
 137     va_start(args, format);
 138     vfprintf(file, format, args);
 139     va_end(args);
 140
 141     putc(':', file);
 142     backtrace_capture(&backtrace);
 143     for (i = 0; i < backtrace.n_frames; i++) {
 144         fprintf(file, " 0x%"PRIxPTR, backtrace.frames[i]);
 145     }
 146     putc('\n', file);
 147 }
 148
 149 static void
 150 reset_hooks(void)
 151 {
 152     static int count;
 153
 154     if (file) {
 155         if (ferror(file)) {
 156             VLOG_WARN("error writing leak checker log file");
 157             leak_checker_stop();
 158             return;
 159         }
 160
 161         if (count++ >= 100 && limit) {
 162             struct stat s;
 163             count = 0;
 164             if (fstat(fileno(file), &s) < 0) {
 165                 VLOG_WARN("cannot fstat leak checker log file: %s",
 166                           strerror(errno));
 167                 leak_checker_stop();
 168                 return;
 169             }
 170             if (s.st_size > limit) {
 171                 VLOG_WARN("leak checker log file size exceeded limit");
 172                 leak_checker_stop();
 173                 return;
 174             }
 175         }
 176     }
 177     if (file) {
 178         set_hooks(&our_hooks);
 179     }
 180 }
 181
 182 static void *
 183 hook_malloc(size_t size, const void *caller OVS_UNUSED)
 184 {
 185     void *p;
 186
 187     set_hooks(&libc_hooks);
 188     p = malloc(size);
 189     get_hooks(&libc_hooks);
 190
 191     log_callers("malloc(%zu) -> %p", size, p);
 192
 193     reset_hooks();
 194     return p;
 195 }
 196
 197 void
 198 leak_checker_claim(const void *p)
 199 {
 200     if (!file) {
 201         return;
 202     }
 203
 204     if (p) {
 205         set_hooks(&libc_hooks);
 206         log_callers("claim(%p)", p);
 207         reset_hooks();
 208     }
 209 }
 210
 211 static void
 212 hook_free(void *p, const void *caller OVS_UNUSED)
 213 {
 214     if (!p) {
 215         return;
 216     }
 217
 218     set_hooks(&libc_hooks);
 219     log_callers("free(%p)", p);
 220     free(p);
 221     get_hooks(&libc_hooks);
 222
 223     reset_hooks();
 224 }
 225
 226 static void *
 227 hook_realloc(void *p, size_t size, const void *caller OVS_UNUSED)
 228 {
 229     void *q;
 230
 231     set_hooks(&libc_hooks);
 232     q = realloc(p, size);
 233     get_hooks(&libc_hooks);
 234
 235     if (p != q) {
 236         log_callers("realloc(%p, %zu) -> %p", p, size, q);
 237     }
 238
 239     reset_hooks();
 240
 241     return q;
 242 }
 243 #endif /* HAVE_MALLOC_HOOKS */