2
* BinReloc - a library for creating relocatable executables
3
* Written by: Hongli Lai <h.lai@chello.nl>
4
* http://autopackage.org/
6
* This source code is public domain. You can relicense this code
7
* under whatever license you want.
9
* See http://autopackage.org/docs/binreloc/ for
10
* more information and how to use this.
13
#ifndef __BINRELOC_C__
14
#define __BINRELOC_C__
16
#ifdef ENABLE_BINRELOC
17
#include <sys/types.h>
20
#endif /* ENABLE_BINRELOC */
31
* Find the canonical filename of the executable. Returns the filename
32
* (which must be freed) or NULL on error. If the parameter 'error' is
33
* not NULL, the error code will be stored there, if an error occured.
36
_br_find_exe (GbrInitError *error)
38
#ifndef ENABLE_BINRELOC
40
*error = _MG_GBR_INIT_ERROR_DISABLED;
43
char *path, *path2, *line, *result;
49
/* Read from /proc/self/exe (symlink) */
50
if (sizeof (path) > SSIZE_MAX)
51
buf_size = SSIZE_MAX - 1;
53
buf_size = PATH_MAX - 1;
54
path = (char *) g_try_malloc (buf_size);
56
/* Cannot allocate memory. */
58
*error = _MG_GBR_INIT_ERROR_NOMEM;
61
path2 = (char *) g_try_malloc (buf_size);
63
/* Cannot allocate memory. */
65
*error = _MG_GBR_INIT_ERROR_NOMEM;
70
strncpy (path2, "/proc/self/exe", buf_size - 1);
75
size = readlink (path2, path, buf_size - 1);
82
/* readlink() success. */
85
/* Check whether the symlink's target is also a symlink.
86
* We want to get the final target. */
87
i = stat (path, &stat_buf);
95
if (!S_ISLNK (stat_buf.st_mode)) {
96
/* path is not a symlink. Done. */
101
/* path is a symlink. Continue loop and resolve this. */
102
strncpy (path, path2, buf_size - 1);
106
/* readlink() or stat() failed; this can happen when the program is
107
* running in Valgrind 2.2. Read from /proc/self/maps as fallback. */
109
buf_size = PATH_MAX + 128;
110
line = (char *) g_try_realloc (path, buf_size);
112
/* Cannot allocate memory. */
115
*error = _MG_GBR_INIT_ERROR_NOMEM;
119
f = fopen ("/proc/self/maps", "r");
123
*error = _MG_GBR_INIT_ERROR_OPEN_MAPS;
127
/* The first entry should be the executable name. */
128
result = fgets (line, (int) buf_size, f);
129
if (result == NULL) {
133
*error = _MG_GBR_INIT_ERROR_READ_MAPS;
137
/* Get rid of newline character. */
138
buf_size = strlen (line);
140
/* Huh? An empty string? */
144
*error = _MG_GBR_INIT_ERROR_INVALID_MAPS;
147
if (line[buf_size - 1] == 10)
148
line[buf_size - 1] = 0;
150
/* Extract the filename; it is always an absolute path. */
151
path = strchr (line, '/');
154
if (strstr (line, " r-xp ") == NULL || path == NULL) {
158
*error = _MG_GBR_INIT_ERROR_INVALID_MAPS;
162
path = g_strdup (path);
166
#endif /* ENABLE_BINRELOC */
171
* Find the canonical filename of the executable which owns symbol.
172
* Returns a filename which must be freed, or NULL on error.
175
_br_find_exe_for_symbol (const void *symbol, GbrInitError *error)
177
#ifndef ENABLE_BINRELOC
179
*error = _MG_GBR_INIT_ERROR_DISABLED;
180
return (char *) NULL;
182
#define SIZE PATH_MAX + 100
184
size_t address_string_len;
185
char *address_string, line[SIZE], *found;
188
return (char *) NULL;
190
f = fopen ("/proc/self/maps", "r");
192
return (char *) NULL;
194
address_string_len = 4;
195
address_string = (char *) g_try_malloc (address_string_len);
196
found = (char *) NULL;
199
char *start_addr, *end_addr, *end_addr_end, *file;
200
void *start_addr_p, *end_addr_p;
203
if (fgets (line, SIZE, f) == NULL)
207
if (strstr (line, " r-xp ") == NULL || strchr (line, '/') == NULL)
212
end_addr = strchr (line, '-');
213
file = strchr (line, '/');
215
/* More sanity check. */
216
if (!(file > end_addr && end_addr != NULL && end_addr[0] == '-'))
221
end_addr_end = strchr (end_addr, ' ');
222
if (end_addr_end == NULL)
225
end_addr_end[0] = '\0';
229
if (file[len - 1] == '\n')
230
file[len - 1] = '\0';
232
/* Get rid of "(deleted)" from the filename. */
234
if (len > 10 && strcmp (file + len - 10, " (deleted)") == 0)
235
file[len - 10] = '\0';
237
/* I don't know whether this can happen but better safe than sorry. */
238
len = strlen (start_addr);
239
if (len != strlen (end_addr))
243
/* Transform the addresses into a string in the form of 0xdeadbeef,
244
* then transform that into a pointer. */
245
if (address_string_len < len + 3) {
246
address_string_len = len + 3;
247
address_string = (char *) g_try_realloc (address_string, address_string_len);
250
memcpy (address_string, "0x", 2);
251
memcpy (address_string + 2, start_addr, len);
252
address_string[2 + len] = '\0';
253
sscanf (address_string, "%p", &start_addr_p);
255
memcpy (address_string, "0x", 2);
256
memcpy (address_string + 2, end_addr, len);
257
address_string[2 + len] = '\0';
258
sscanf (address_string, "%p", &end_addr_p);
261
if (symbol >= start_addr_p && symbol < end_addr_p) {
267
g_free (address_string);
271
return (char *) NULL;
273
return g_strdup (found);
274
#endif /* ENABLE_BINRELOC */
278
static gchar *exe = NULL;
280
static void set_gerror (GError **error, GbrInitError errcode);
283
/** Initialize the BinReloc library (for applications).
285
* This function must be called before using any other BinReloc functions.
286
* It attempts to locate the application's canonical filename.
288
* @note If you want to use BinReloc for a library, then you should call
289
* _mg_gbr_init_lib() instead.
291
* @param error If BinReloc failed to initialize, then the error report will
292
* be stored in this variable. Set to NULL if you don't want an
293
* error report. See the #GbrInitError for a list of error
296
* @returns TRUE on success, FALSE if BinReloc failed to initialize.
299
_mg_gbr_init (GError **error)
301
GbrInitError errcode;
303
/* Locate the application's filename. */
304
exe = _br_find_exe (&errcode);
310
set_gerror (error, errcode);
316
/** Initialize the BinReloc library (for libraries).
318
* This function must be called before using any other BinReloc functions.
319
* It attempts to locate the calling library's canonical filename.
321
* @note The BinReloc source code MUST be included in your library, or this
322
* function won't work correctly.
324
* @returns TRUE on success, FALSE if a filename cannot be found.
327
_mg_gbr_init_lib (GError **error)
329
GbrInitError errcode;
331
exe = _br_find_exe_for_symbol ((const void *) "", &errcode);
337
set_gerror (error, errcode);
344
set_gerror (GError **error, GbrInitError errcode)
346
gchar *error_message;
352
case _MG_GBR_INIT_ERROR_NOMEM:
353
error_message = "Cannot allocate memory.";
355
case _MG_GBR_INIT_ERROR_OPEN_MAPS:
356
error_message = "Unable to open /proc/self/maps for reading.";
358
case _MG_GBR_INIT_ERROR_READ_MAPS:
359
error_message = "Unable to read from /proc/self/maps.";
361
case _MG_GBR_INIT_ERROR_INVALID_MAPS:
362
error_message = "The file format of /proc/self/maps is invalid.";
364
case _MG_GBR_INIT_ERROR_DISABLED:
365
error_message = "Binary relocation support is disabled.";
368
error_message = "Unknown error.";
371
g_set_error (error, g_quark_from_static_string ("GBinReloc"),
372
errcode, "%s", error_message);
376
/** Find the canonical filename of the current application.
378
* @param default_exe A default filename which will be used as fallback.
379
* @returns A string containing the application's canonical filename,
380
* which must be freed when no longer necessary. If BinReloc is
381
* not initialized, or if the initialization function failed,
382
* then a copy of default_exe will be returned. If default_exe
383
* is NULL, then NULL will be returned.
386
_mg_gbr_find_exe (const gchar *default_exe)
389
/* BinReloc is not initialized. */
390
if (default_exe != NULL)
391
return g_strdup (default_exe);
395
return g_strdup (exe);
399
/** Locate the directory in which the current application is installed.
401
* The prefix is generated by the following pseudo-code evaluation:
406
* @param default_dir A default directory which will used as fallback.
407
* @return A string containing the directory, which must be freed when no
408
* longer necessary. If BinReloc is not initialized, or if the
409
* initialization function failed, then a copy of default_dir
410
* will be returned. If default_dir is NULL, then NULL will be
414
_mg_gbr_find_exe_dir (const gchar *default_dir)
417
/* BinReloc not initialized. */
418
if (default_dir != NULL)
419
return g_strdup (default_dir);
424
return g_path_get_dirname (exe);
428
/** Locate the prefix in which the current application is installed.
430
* The prefix is generated by the following pseudo-code evaluation:
432
* dirname(dirname(exename))
435
* @param default_prefix A default prefix which will used as fallback.
436
* @return A string containing the prefix, which must be freed when no
437
* longer necessary. If BinReloc is not initialized, or if the
438
* initialization function failed, then a copy of default_prefix
439
* will be returned. If default_prefix is NULL, then NULL will be
443
_mg_gbr_find_prefix (const gchar *default_prefix)
448
/* BinReloc not initialized. */
449
if (default_prefix != NULL)
450
return g_strdup (default_prefix);
455
dir1 = g_path_get_dirname (exe);
456
dir2 = g_path_get_dirname (dir1);
462
/** Locate the application's binary folder.
464
* The path is generated by the following pseudo-code evaluation:
469
* @param default_bin_dir A default path which will used as fallback.
470
* @return A string containing the bin folder's path, which must be freed when
471
* no longer necessary. If BinReloc is not initialized, or if the
472
* initialization function failed, then a copy of default_bin_dir will
473
* be returned. If default_bin_dir is NULL, then NULL will be returned.
476
_mg_gbr_find_bin_dir (const gchar *default_bin_dir)
480
prefix = _mg_gbr_find_prefix (NULL);
481
if (prefix == NULL) {
482
/* BinReloc not initialized. */
483
if (default_bin_dir != NULL)
484
return g_strdup (default_bin_dir);
489
dir = g_build_filename (prefix, "bin", NULL);
495
/** Locate the application's superuser binary folder.
497
* The path is generated by the following pseudo-code evaluation:
502
* @param default_sbin_dir A default path which will used as fallback.
503
* @return A string containing the sbin folder's path, which must be freed when
504
* no longer necessary. If BinReloc is not initialized, or if the
505
* initialization function failed, then a copy of default_sbin_dir will
506
* be returned. If default_bin_dir is NULL, then NULL will be returned.
509
_mg_gbr_find_sbin_dir (const gchar *default_sbin_dir)
513
prefix = _mg_gbr_find_prefix (NULL);
514
if (prefix == NULL) {
515
/* BinReloc not initialized. */
516
if (default_sbin_dir != NULL)
517
return g_strdup (default_sbin_dir);
522
dir = g_build_filename (prefix, "sbin", NULL);
528
/** Locate the application's data folder.
530
* The path is generated by the following pseudo-code evaluation:
535
* @param default_data_dir A default path which will used as fallback.
536
* @return A string containing the data folder's path, which must be freed when
537
* no longer necessary. If BinReloc is not initialized, or if the
538
* initialization function failed, then a copy of default_data_dir
539
* will be returned. If default_data_dir is NULL, then NULL will be
543
_mg_gbr_find_data_dir (const gchar *default_data_dir)
547
prefix = _mg_gbr_find_prefix (NULL);
548
if (prefix == NULL) {
549
/* BinReloc not initialized. */
550
if (default_data_dir != NULL)
551
return g_strdup (default_data_dir);
556
dir = g_build_filename (prefix, "share", NULL);
562
/** Locate the application's localization folder.
564
* The path is generated by the following pseudo-code evaluation:
566
* prefix + "/share/locale"
569
* @param default_locale_dir A default path which will used as fallback.
570
* @return A string containing the localization folder's path, which must be freed when
571
* no longer necessary. If BinReloc is not initialized, or if the
572
* initialization function failed, then a copy of default_locale_dir will be returned.
573
* If default_locale_dir is NULL, then NULL will be returned.
576
_mg_gbr_find_locale_dir (const gchar *default_locale_dir)
578
gchar *data_dir, *dir;
580
data_dir = _mg_gbr_find_data_dir (NULL);
581
if (data_dir == NULL) {
582
/* BinReloc not initialized. */
583
if (default_locale_dir != NULL)
584
return g_strdup (default_locale_dir);
589
dir = g_build_filename (data_dir, "locale", NULL);
595
/** Locate the application's library folder.
597
* The path is generated by the following pseudo-code evaluation:
602
* @param default_lib_dir A default path which will used as fallback.
603
* @return A string containing the library folder's path, which must be freed when
604
* no longer necessary. If BinReloc is not initialized, or if the
605
* initialization function failed, then a copy of default_lib_dir will be returned.
606
* If default_lib_dir is NULL, then NULL will be returned.
609
_mg_gbr_find_lib_dir (const gchar *default_lib_dir)
613
prefix = _mg_gbr_find_prefix (NULL);
614
if (prefix == NULL) {
615
/* BinReloc not initialized. */
616
if (default_lib_dir != NULL)
617
return g_strdup (default_lib_dir);
622
dir = g_build_filename (prefix, "lib", NULL);
628
/** Locate the application's libexec folder.
630
* The path is generated by the following pseudo-code evaluation:
632
* prefix + "/libexec"
635
* @param default_libexec_dir A default path which will used as fallback.
636
* @return A string containing the libexec folder's path, which must be freed when
637
* no longer necessary. If BinReloc is not initialized, or if the initialization
638
* function failed, then a copy of default_libexec_dir will be returned.
639
* If default_libexec_dir is NULL, then NULL will be returned.
642
_mg_gbr_find_libexec_dir (const gchar *default_libexec_dir)
646
prefix = _mg_gbr_find_prefix (NULL);
647
if (prefix == NULL) {
648
/* BinReloc not initialized. */
649
if (default_libexec_dir != NULL)
650
return g_strdup (default_libexec_dir);
655
dir = g_build_filename (prefix, "libexec", NULL);
661
/** Locate the application's configuration files folder.
663
* The path is generated by the following pseudo-code evaluation:
668
* @param default_etc_dir A default path which will used as fallback.
669
* @return A string containing the etc folder's path, which must be freed when
670
* no longer necessary. If BinReloc is not initialized, or if the initialization
671
* function failed, then a copy of default_etc_dir will be returned.
672
* If default_etc_dir is NULL, then NULL will be returned.
675
_mg_gbr_find_etc_dir (const gchar *default_etc_dir)
679
prefix = _mg_gbr_find_prefix (NULL);
680
if (prefix == NULL) {
681
/* BinReloc not initialized. */
682
if (default_etc_dir != NULL)
683
return g_strdup (default_etc_dir);
688
dir = g_build_filename (prefix, "etc", NULL);
696
#endif /* __BINRELOC_C__ */