/* * BinReloc - a library for creating relocatable executables * * Originally written by: Hongli Lai * http://autopackage.org/ (defunct) * * Maintained by: Wolfgang 'datenwolf' Draxinger * * DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE * Version 2, December 2004 * * Everyone is permitted to copy and distribute verbatim or modified * copies of this license document, and changing it is allowed as long * as the name is changed. * * DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE * TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION * * 0. You just DO WHAT THE FUCK YOU WANT TO. */ #include #include #include #include #include #include #include #include #include #include "binreloc.h" #ifndef SSIZE_MAX #define SSIZE_MAX ((ssize_t)(SIZE_MAX>>1)) #endif /** @internal * Find the canonical filename of the executable. Returns the filename * (which must be freed) or NULL on error. If the parameter 'error' is * not NULL, the error code will be stored there, if an error occured. */ static char * _br_find_exe (BrInitError *error) { char *path, *path2, *line, *result; size_t buf_size; struct stat stat_buf; FILE *f; /* Read from /proc/self/exe (symlink) */ if (sizeof (path) > SSIZE_MAX) buf_size = SSIZE_MAX - 1; else buf_size = PATH_MAX - 1; path = (char *) malloc (buf_size); if (path == NULL) { /* Cannot allocate memory. */ if (error) *error = BR_INIT_ERROR_NOMEM; return NULL; } path2 = (char *) malloc (buf_size); if (path2 == NULL) { /* Cannot allocate memory. */ if (error) *error = BR_INIT_ERROR_NOMEM; free (path); return NULL; } strncpy (path2, "/proc/self/exe", buf_size - 1); while (1) { int i; ssize_t size = readlink (path2, path, buf_size - 1); if (size == -1) { /* Error. */ free (path2); break; } /* readlink() success. */ path[size] = '\0'; /* Check whether the symlink's target is also a symlink. * We want to get the final target. */ i = stat (path, &stat_buf); if (i == -1) { /* Error. */ free (path2); break; } /* stat() success. */ if (!S_ISLNK (stat_buf.st_mode)) { /* path is not a symlink. Done. */ free (path2); return path; } /* path is a symlink. Continue loop and resolve this. */ strncpy (path, path2, buf_size - 1); } /* readlink() or stat() failed; this can happen when the program is * running in Valgrind 2.2. Read from /proc/self/maps as fallback. */ buf_size = PATH_MAX + 128; line = (char *) realloc (path, buf_size); if (line == NULL) { /* Cannot allocate memory. */ free (path); if (error) *error = BR_INIT_ERROR_NOMEM; return NULL; } f = fopen ("/proc/self/maps", "r"); if (f == NULL) { free (line); if (error) *error = BR_INIT_ERROR_OPEN_MAPS; return NULL; } /* The first entry should be the executable name. */ result = fgets (line, (int) buf_size, f); if (result == NULL) { fclose (f); free (line); if (error) *error = BR_INIT_ERROR_READ_MAPS; return NULL; } /* Get rid of newline character. */ buf_size = strlen (line); if (buf_size == 0) { /* Huh? An empty string? */ fclose (f); free (line); if (error) *error = BR_INIT_ERROR_INVALID_MAPS; return NULL; } if (line[buf_size - 1] == 10) line[buf_size - 1] = 0; /* Extract the filename; it is always an absolute path. */ path = strchr (line, '/'); /* Sanity check. */ if (strstr (line, " r-xp ") == NULL || path == NULL) { fclose (f); free (line); if (error) *error = BR_INIT_ERROR_INVALID_MAPS; return NULL; } path = strdup (path); free (line); fclose (f); return path; } /** @internal * Find the canonical filename of the executable which owns symbol. * Returns a filename which must be freed, or NULL on error. */ static char * _br_find_exe_for_symbol (const void *symbol, BrInitError *error) { #define SIZE PATH_MAX + 100 FILE *f; size_t address_string_len; char *address_string, line[SIZE], *found; if (symbol == NULL) return (char *) NULL; f = fopen ("/proc/self/maps", "r"); if (f == NULL) return (char *) NULL; address_string_len = 4; address_string = (char *) malloc (address_string_len); found = (char *) NULL; while (!feof (f)) { char *start_addr, *end_addr, *end_addr_end, *file; void *start_addr_p, *end_addr_p; size_t len; if (fgets (line, SIZE, f) == NULL) break; /* Sanity check. */ if (strstr (line, " r-xp ") == NULL || strchr (line, '/') == NULL) continue; /* Parse line. */ start_addr = line; end_addr = strchr (line, '-'); file = strchr (line, '/'); /* More sanity check. */ if (!(file > end_addr && end_addr != NULL && end_addr[0] == '-')) continue; end_addr[0] = '\0'; end_addr++; end_addr_end = strchr (end_addr, ' '); if (end_addr_end == NULL) continue; end_addr_end[0] = '\0'; len = strlen (file); if (len == 0) continue; if (file[len - 1] == '\n') file[len - 1] = '\0'; /* Get rid of "(deleted)" from the filename. */ len = strlen (file); if (len > 10 && strcmp (file + len - 10, " (deleted)") == 0) file[len - 10] = '\0'; /* I don't know whether this can happen but better safe than sorry. */ len = strlen (start_addr); if (len != strlen (end_addr)) continue; /* Transform the addresses into a string in the form of 0xdeadbeef, * then transform that into a pointer. */ if (address_string_len < len + 3) { address_string_len = len + 3; char *new_address_string = (char *) realloc (address_string, address_string_len); if (new_address_string == NULL){ *error = BR_INIT_ERROR_NOMEM; return (char *) NULL; } else address_string = new_address_string; } memcpy (address_string, "0x", 2); memcpy (address_string + 2, start_addr, len); address_string[2 + len] = '\0'; sscanf (address_string, "%p", &start_addr_p); memcpy (address_string, "0x", 2); memcpy (address_string + 2, end_addr, len); address_string[2 + len] = '\0'; sscanf (address_string, "%p", &end_addr_p); if (symbol >= start_addr_p && symbol < end_addr_p) { found = file; break; } } free (address_string); fclose (f); if (found == NULL) return (char *) NULL; else return strdup (found); } #ifndef BINRELOC_RUNNING_DOXYGEN #undef NULL #define NULL ((void *) 0) /* typecasted as char* for C++ type safeness */ #endif static char *exe = (char *) NULL; /** Initialize the BinReloc library (for applications). * * This function must be called before using any other BinReloc functions. * It attempts to locate the application's canonical filename. * * @note If you want to use BinReloc for a library, then you should call * br_init_lib() instead. * * @param error If BinReloc failed to initialize, then the error code will * be stored in this variable. Set to NULL if you want to * ignore this. See #BrInitError for a list of error codes. * * @returns 1 on success, 0 if BinReloc failed to initialize. */ int br_init (BrInitError *error) { exe = _br_find_exe (error); return exe != NULL; } /** Initialize the BinReloc library (for libraries). * * This function must be called before using any other BinReloc functions. * It attempts to locate the calling library's canonical filename. * * @note The BinReloc source code MUST be included in your library, or this * function won't work correctly. * * @param error If BinReloc failed to initialize, then the error code will * be stored in this variable. Set to NULL if you want to * ignore this. See #BrInitError for a list of error codes. * * @returns 1 on success, 0 if a filename cannot be found. */ int br_init_lib (BrInitError *error) { exe = _br_find_exe_for_symbol ((const void *) "", error); return exe != NULL; } /** Find the canonical filename of the current application. * * @param default_exe A default filename which will be used as fallback. * @returns A string containing the application's canonical filename, * which must be freed when no longer necessary. If BinReloc is * not initialized, or if br_init() failed, then a copy of * default_exe will be returned. If default_exe is NULL, then * NULL will be returned. */ char * br_find_exe (const char *default_exe) { if (exe == (char *) NULL) { /* BinReloc is not initialized. */ if (default_exe != (const char *) NULL) return strdup (default_exe); else return (char *) NULL; } return strdup (exe); } /** Locate the directory in which the current application is installed. * * The prefix is generated by the following pseudo-code evaluation: * \code * dirname(exename) * \endcode * * @param default_dir A default directory which will used as fallback. * @return A string containing the directory, which must be freed when no * longer necessary. If BinReloc is not initialized, or if the * initialization function failed, then a copy of default_dir * will be returned. If default_dir is NULL, then NULL will be * returned. */ char * br_find_exe_dir (const char *default_dir) { if (exe == NULL) { /* BinReloc not initialized. */ if (default_dir != NULL) return strdup (default_dir); else return NULL; } return br_dirname (exe); } /** Locate the prefix in which the current application is installed. * * The prefix is generated by the following pseudo-code evaluation: * \code * dirname(dirname(exename)) * \endcode * * @param default_prefix A default prefix which will used as fallback. * @return A string containing the prefix, which must be freed when no * longer necessary. If BinReloc is not initialized, or if * the initialization function failed, then a copy of default_prefix * will be returned. If default_prefix is NULL, then NULL will be returned. */ char * br_find_prefix (const char *default_prefix) { char *dir1, *dir2; if (exe == (char *) NULL) { /* BinReloc not initialized. */ if (default_prefix != (const char *) NULL) return strdup (default_prefix); else return (char *) NULL; } dir1 = br_dirname (exe); dir2 = br_dirname (dir1); free (dir1); return dir2; } /** Locate the application's binary folder. * * The path is generated by the following pseudo-code evaluation: * \code * prefix + "/bin" * \endcode * * @param default_bin_dir A default path which will used as fallback. * @return A string containing the bin folder's path, which must be freed when * no longer necessary. If BinReloc is not initialized, or if * the initialization function failed, then a copy of default_bin_dir will * be returned. If default_bin_dir is NULL, then NULL will be returned. */ char * br_find_bin_dir (const char *default_bin_dir) { char *prefix, *dir; prefix = br_find_prefix ((const char *) NULL); if (prefix == (char *) NULL) { /* BinReloc not initialized. */ if (default_bin_dir != (const char *) NULL) return strdup (default_bin_dir); else return (char *) NULL; } dir = br_build_path (prefix, "bin"); free (prefix); return dir; } /** Locate the application's superuser binary folder. * * The path is generated by the following pseudo-code evaluation: * \code * prefix + "/sbin" * \endcode * * @param default_sbin_dir A default path which will used as fallback. * @return A string containing the sbin folder's path, which must be freed when * no longer necessary. If BinReloc is not initialized, or if the * initialization function failed, then a copy of default_sbin_dir will * be returned. If default_bin_dir is NULL, then NULL will be returned. */ char * br_find_sbin_dir (const char *default_sbin_dir) { char *prefix, *dir; prefix = br_find_prefix ((const char *) NULL); if (prefix == (char *) NULL) { /* BinReloc not initialized. */ if (default_sbin_dir != (const char *) NULL) return strdup (default_sbin_dir); else return (char *) NULL; } dir = br_build_path (prefix, "sbin"); free (prefix); return dir; } /** Locate the application's data folder. * * The path is generated by the following pseudo-code evaluation: * \code * prefix + "/share" * \endcode * * @param default_data_dir A default path which will used as fallback. * @return A string containing the data folder's path, which must be freed when * no longer necessary. If BinReloc is not initialized, or if the * initialization function failed, then a copy of default_data_dir * will be returned. If default_data_dir is NULL, then NULL will be * returned. */ char * br_find_data_dir (const char *default_data_dir) { char *prefix, *dir; prefix = br_find_prefix ((const char *) NULL); if (prefix == (char *) NULL) { /* BinReloc not initialized. */ if (default_data_dir != (const char *) NULL) return strdup (default_data_dir); else return (char *) NULL; } dir = br_build_path (prefix, "share"); free (prefix); return dir; } /** Locate the application's localization folder. * * The path is generated by the following pseudo-code evaluation: * \code * prefix + "/share/locale" * \endcode * * @param default_locale_dir A default path which will used as fallback. * @return A string containing the localization folder's path, which must be freed when * no longer necessary. If BinReloc is not initialized, or if the * initialization function failed, then a copy of default_locale_dir will be returned. * If default_locale_dir is NULL, then NULL will be returned. */ char * br_find_locale_dir (const char *default_locale_dir) { char *data_dir, *dir; data_dir = br_find_data_dir ((const char *) NULL); if (data_dir == (char *) NULL) { /* BinReloc not initialized. */ if (default_locale_dir != (const char *) NULL) return strdup (default_locale_dir); else return (char *) NULL; } dir = br_build_path (data_dir, "locale"); free (data_dir); return dir; } /** Locate the application's library folder. * * The path is generated by the following pseudo-code evaluation: * \code * prefix + "/lib" * \endcode * * @param default_lib_dir A default path which will used as fallback. * @return A string containing the library folder's path, which must be freed when * no longer necessary. If BinReloc is not initialized, or if the initialization * function failed, then a copy of default_lib_dir will be returned. * If default_lib_dir is NULL, then NULL will be returned. */ char * br_find_lib_dir (const char *default_lib_dir) { char *prefix, *dir; prefix = br_find_prefix ((const char *) NULL); if (prefix == (char *) NULL) { /* BinReloc not initialized. */ if (default_lib_dir != (const char *) NULL) return strdup (default_lib_dir); else return (char *) NULL; } dir = br_build_path (prefix, "lib"); free (prefix); return dir; } /** Locate the application's libexec folder. * * The path is generated by the following pseudo-code evaluation: * \code * prefix + "/libexec" * \endcode * * @param default_libexec_dir A default path which will used as fallback. * @return A string containing the libexec folder's path, which must be freed when * no longer necessary. If BinReloc is not initialized, or if the initialization * function failed, then a copy of default_libexec_dir will be returned. * If default_libexec_dir is NULL, then NULL will be returned. */ char * br_find_libexec_dir (const char *default_libexec_dir) { char *prefix, *dir; prefix = br_find_prefix ((const char *) NULL); if (prefix == (char *) NULL) { /* BinReloc not initialized. */ if (default_libexec_dir != (const char *) NULL) return strdup (default_libexec_dir); else return (char *) NULL; } dir = br_build_path (prefix, "libexec"); free (prefix); return dir; } /** Locate the application's configuration files folder. * * The path is generated by the following pseudo-code evaluation: * \code * prefix + "/etc" * \endcode * * @param default_etc_dir A default path which will used as fallback. * @return A string containing the etc folder's path, which must be freed when * no longer necessary. If BinReloc is not initialized, or if the initialization * function failed, then a copy of default_etc_dir will be returned. * If default_etc_dir is NULL, then NULL will be returned. */ char * br_find_etc_dir (const char *default_etc_dir) { char *prefix, *dir; prefix = br_find_prefix ((const char *) NULL); if (prefix == (char *) NULL) { /* BinReloc not initialized. */ if (default_etc_dir != (const char *) NULL) return strdup (default_etc_dir); else return (char *) NULL; } dir = br_build_path (prefix, "etc"); free (prefix); return dir; } /*********************** * Utility functions ***********************/ /** Concatenate str1 and str2 to a newly allocated string. * * @param str1 A string. * @param str2 Another string. * @returns A newly-allocated string. This string should be freed when no longer needed. */ char * br_strcat (const char *str1, const char *str2) { char *result; size_t len1, len2; if (str1 == NULL) str1 = ""; if (str2 == NULL) str2 = ""; len1 = strlen (str1); len2 = strlen (str2); result = (char *) malloc (len1 + len2 + 1); memcpy (result, str1, len1); memcpy (result + len1, str2, len2); result[len1 + len2] = '\0'; return result; } char * br_build_path (const char *dir, const char *file) { char *result; size_t len; len = strlen (dir); if (len > 0 && dir[len - 1] != '/') { char *dir2 = br_strcat (dir, "/"); result = br_strcat (dir2, file); free (dir2); } else result = br_strcat (dir, file); return result; } /* Emulates glibc's strndup() */ static char * br_strndup (const char *str, size_t size) { char *result = (char *) NULL; size_t len; if (str == (const char *) NULL) return (char *) NULL; len = strlen (str); if (len == 0) return strdup (""); if (size > len) size = len; result = (char *) malloc (len + 1); memcpy (result, str, size); result[size] = '\0'; return result; } /** Extracts the directory component of a path. * * Similar to g_dirname() or the dirname commandline application. * * Example: * \code * br_dirname ("/usr/local/foobar"); --> Returns: "/usr/local" * \endcode * * @param path A path. * @returns A directory name. This string should be freed when no longer needed. */ char * br_dirname (const char *path) { char *end, *result; if (path == (const char *) NULL) return (char *) NULL; end = strrchr (path, '/'); if (end == (const char *) NULL) return strdup ("."); while (end > path && *end == '/') end--; result = br_strndup (path, (size_t)(end - path + 1)); if (result[0] == 0) { free (result); return strdup ("/"); } else return result; }