1 /* Wrappers around malloc and memory debugging support.
2 Copyright (C) 2003 Free Software Foundation, Inc.
4 This file is part of GNU Wget.
6 GNU Wget is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 GNU Wget is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with Wget; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 In addition, as a special exception, the Free Software Foundation
21 gives permission to link the code of its release of Wget with the
22 OpenSSL project's "OpenSSL" library (or with modified versions of it
23 that use the same license as the "OpenSSL" library), and distribute
24 the linked executables. You must obey the GNU General Public License
25 in all respects for all of the code used other than "OpenSSL". If you
26 modify this file, you may extend this exception to your version of the
27 file, but you are not obligated to do so. If you do not wish to do
28 so, delete this exception statement from your version. */
36 #else /* not HAVE_STRING_H */
38 #endif /* not HAVE_STRING_H */
39 #include <sys/types.h>
50 /* This file implements several wrappers around the basic allocation
51 routines. This is done for two reasons: first, so that the callers
52 of these functions need not check for errors, which is easy to
53 forget. If there is not enough virtual memory for running Wget,
54 something is seriously wrong, and Wget exits with an appropriate
57 The second reason why these are useful is that, if DEBUG_MALLOC is
58 defined, they also provide a handy (if crude) malloc debugging
59 interface that checks for memory leaks. */
61 /* Croak the fatal memory error and bail out with non-zero exit
65 memfatal (const char *context, long attempted_size)
67 /* Make sure we don't try to store part of the log line, and thus
69 log_set_save_context (0);
70 logprintf (LOG_ALWAYS,
71 _("%s: %s: Failed to allocate %ld bytes; memory exhausted.\n"),
72 exec_name, context, attempted_size);
76 /* These functions end with _real because they need to be
77 distinguished from the debugging functions, and from the macros.
80 If memory debugging is not turned on, xmalloc.h defines these:
82 #define xmalloc xmalloc_real
83 #define xmalloc0 xmalloc0_real
84 #define xrealloc xrealloc_real
85 #define xstrdup xstrdup_real
88 In case of memory debugging, the definitions are a bit more
89 complex, because we want to provide more information, *and* we want
90 to call the debugging code. (The former is the reason why xmalloc
91 and friends need to be macros in the first place.) Then it looks
94 #define xmalloc(a) xmalloc_debug (a, __FILE__, __LINE__)
95 #define xmalloc0(a) xmalloc0_debug (a, __FILE__, __LINE__)
96 #define xfree(a) xfree_debug (a, __FILE__, __LINE__)
97 #define xrealloc(a, b) xrealloc_debug (a, b, __FILE__, __LINE__)
98 #define xstrdup(a) xstrdup_debug (a, __FILE__, __LINE__)
100 Each of the *_debug function does its magic and calls the real one. */
103 # define STATIC_IF_DEBUG static
105 # define STATIC_IF_DEBUG
108 STATIC_IF_DEBUG void *
109 xmalloc_real (size_t size)
111 void *ptr = malloc (size);
113 memfatal ("malloc", size);
117 STATIC_IF_DEBUG void *
118 xmalloc0_real (size_t size)
120 /* Using calloc can be faster than malloc+memset because some calloc
121 implementations know when they're dealing with zeroed-out memory
122 from the system and can avoid unnecessary memset. */
123 void *ptr = calloc (1, size);
125 memfatal ("calloc", size);
129 STATIC_IF_DEBUG void *
130 xrealloc_real (void *ptr, size_t newsize)
134 /* Not all Un*xes have the feature of realloc() that calling it with
135 a NULL-pointer is the same as malloc(), but it is easy to
138 newptr = realloc (ptr, newsize);
140 newptr = malloc (newsize);
142 memfatal ("realloc", newsize);
146 STATIC_IF_DEBUG char *
147 xstrdup_real (const char *s)
153 copy = malloc (l + 1);
155 memfatal ("strdup", l + 1);
156 memcpy (copy, s, l + 1);
157 #else /* HAVE_STRDUP */
160 memfatal ("strdup", 1 + strlen (s));
161 #endif /* HAVE_STRDUP */
166 /* xfree_real is unnecessary because free doesn't require any special
171 /* Crude home-grown routines for debugging some malloc-related
174 * Counting the number of malloc and free invocations, and reporting
175 the "balance", i.e. how many times more malloc was called than it
176 was the case with free.
178 * Making malloc store its entry into a simple array and free remove
179 stuff from that array. At the end, print the pointers which have
180 not been freed, along with the source file and the line number.
181 This also has the side-effect of detecting freeing memory that
184 Note that this kind of memory leak checking strongly depends on
185 every malloc() being followed by a free(), even if the program is
186 about to finish. Wget is careful to free the data structure it
187 allocated in init.c. */
189 static int malloc_count, free_count;
195 } malloc_debug[100000];
197 /* Both register_ptr and unregister_ptr take O(n) operations to run,
198 which can be a real problem. It would be nice to use a hash table
199 for malloc_debug, but the functions in hash.c are not suitable
200 because they can call malloc() themselves. Maybe it would work if
201 the hash table were preallocated to a huge size, and if we set the
202 rehash threshold to 1.0. */
204 /* Register PTR in malloc_debug. Abort if this is not possible
205 (presumably due to the number of current allocations exceeding the
206 size of malloc_debug.) */
209 register_ptr (void *ptr, const char *file, int line)
212 for (i = 0; i < countof (malloc_debug); i++)
213 if (malloc_debug[i].ptr == NULL)
215 malloc_debug[i].ptr = ptr;
216 malloc_debug[i].file = file;
217 malloc_debug[i].line = line;
223 /* Unregister PTR from malloc_debug. Abort if PTR is not present in
224 malloc_debug. (This catches calling free() with a bogus pointer.) */
227 unregister_ptr (void *ptr)
230 for (i = 0; i < countof (malloc_debug); i++)
231 if (malloc_debug[i].ptr == ptr)
233 malloc_debug[i].ptr = NULL;
239 /* Print the malloc debug stats that can be gathered from the above
240 information. Currently this is the count of mallocs, frees, the
241 difference between the two, and the dump of the contents of
242 malloc_debug. The last part are the memory leaks. */
245 print_malloc_debug_stats (void)
248 printf ("\nMalloc: %d\nFree: %d\nBalance: %d\n\n",
249 malloc_count, free_count, malloc_count - free_count);
250 for (i = 0; i < countof (malloc_debug); i++)
251 if (malloc_debug[i].ptr != NULL)
252 printf ("0x%08ld: %s:%d\n", (long)malloc_debug[i].ptr,
253 malloc_debug[i].file, malloc_debug[i].line);
257 xmalloc_debug (size_t size, const char *source_file, int source_line)
259 void *ptr = xmalloc_real (size);
261 register_ptr (ptr, source_file, source_line);
266 xmalloc0_debug (size_t size, const char *source_file, int source_line)
268 void *ptr = xmalloc0_real (size);
270 register_ptr (ptr, source_file, source_line);
275 xrealloc_debug (void *ptr, size_t newsize, const char *source_file, int source_line)
277 void *newptr = xrealloc_real (ptr, newsize);
281 register_ptr (newptr, source_file, source_line);
283 else if (newptr != ptr)
285 unregister_ptr (ptr);
286 register_ptr (newptr, source_file, source_line);
292 xstrdup_debug (const char *s, const char *source_file, int source_line)
294 char *copy = xstrdup_real (s);
296 register_ptr (copy, source_file, source_line);
301 xfree_debug (void *ptr, const char *source_file, int source_line)
303 assert (ptr != NULL);
305 unregister_ptr (ptr);
309 #endif /* DEBUG_MALLOC */