diff options
Diffstat (limited to 'libgimpbase/gimpreloc.c')
| -rw-r--r-- | libgimpbase/gimpreloc.c | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/libgimpbase/gimpreloc.c b/libgimpbase/gimpreloc.c new file mode 100644 index 0000000..b9fa4df --- /dev/null +++ b/libgimpbase/gimpreloc.c @@ -0,0 +1,435 @@ +/* + * BinReloc - a library for creating relocatable executables + * Written by: Hongli Lai <h.lai@chello.nl> + * http://autopackage.org/ + * + * This source code is public domain. You can relicense this code + * under whatever license you want. + * + * See http://autopackage.org/docs/binreloc/ for + * more information and how to use this. + */ + +#include "config.h" + +#include <stdlib.h> +#include <limits.h> +#include <string.h> + +#if defined(ENABLE_RELOCATABLE_RESOURCES) && ! defined(G_OS_WIN32) +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> +#endif /* ENABLE_RELOCATABLE_RESOURCES && ! G_OS_WIN32 */ + +#include <glib.h> +#include <glib/gstdio.h> + +#include "gimpreloc.h" + + +/* + * 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 occurred. + */ +static char * +_br_find_exe (GimpBinrelocInitError *error) +{ +#if ! defined(ENABLE_RELOCATABLE_RESOURCES) || defined(G_OS_WIN32) + if (error) + *error = GIMP_RELOC_INIT_ERROR_DISABLED; + return NULL; +#else + char *path, *path2, *line, *result; + size_t buf_size; + ssize_t 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 = g_try_new (char, buf_size); + if (path == NULL) + { + /* Cannot allocate memory. */ + if (error) + *error = GIMP_RELOC_INIT_ERROR_NOMEM; + return NULL; + } + path2 = g_try_new (char, buf_size); + if (path2 == NULL) + { + /* Cannot allocate memory. */ + if (error) + *error = GIMP_RELOC_INIT_ERROR_NOMEM; + g_free (path); + return NULL; + } + + strncpy (path2, "/proc/self/exe", buf_size - 1); + + while (1) + { + int i; + + size = readlink (path2, path, buf_size - 1); + if (size == -1) + { + /* Error. */ + g_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. */ + g_free (path2); + break; + } + + /* stat() success. */ + if (!S_ISLNK (stat_buf.st_mode)) + { + /* path is not a symlink. Done. */ + g_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 *) g_try_realloc (path, buf_size); + if (line == NULL) + { + /* Cannot allocate memory. */ + g_free (path); + if (error) + *error = GIMP_RELOC_INIT_ERROR_NOMEM; + return NULL; + } + + f = g_fopen ("/proc/self/maps", "r"); + if (f == NULL) + { + g_free (line); + if (error) + *error = GIMP_RELOC_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); + g_free (line); + if (error) + *error = GIMP_RELOC_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); + g_free (line); + if (error) + *error = GIMP_RELOC_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); + g_free (line); + if (error) + *error = GIMP_RELOC_INIT_ERROR_INVALID_MAPS; + return NULL; + } + + path = g_strdup (path); + g_free (line); + fclose (f); + return path; +#endif /* ! ENABLE_RELOCATABLE_RESOURCES || G_OS_WIN32 */ +} + + +/* + * 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, GimpBinrelocInitError *error) +{ +#if ! defined(ENABLE_RELOCATABLE_RESOURCES) || defined(G_OS_WIN32) + if (error) + *error = GIMP_RELOC_INIT_ERROR_DISABLED; + return (char *) NULL; +#else +#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 = g_fopen ("/proc/self/maps", "r"); + if (f == NULL) + return (char *) NULL; + + address_string_len = 4; + address_string = g_try_new (char, 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; + address_string = (char *) g_try_realloc (address_string, address_string_len); + } + + 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; + } + } + + g_free (address_string); + fclose (f); + + if (found == NULL) + return (char *) NULL; + else + return g_strdup (found); +#endif /* ! ENABLE_RELOCATABLE_RESOURCES || G_OS_WIN32 */ +} + + +static gchar *exe = NULL; + +static void set_gerror (GError **error, GimpBinrelocInitError errcode); + + +/* 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 + * _gimp_reloc_init_lib() instead. + * @note Initialization failure is not fatal. BinReloc functions will just + * fallback to the supplied default path. + * + * @param error If BinReloc failed to initialize, then the error report will + * be stored in this variable. Set to NULL if you don't want an + * error report. See the #GimpBinrelocInitError for a list of error + * codes. + * + * @returns TRUE on success, FALSE if BinReloc failed to initialize. + */ +gboolean +_gimp_reloc_init (GError **error) +{ + GimpBinrelocInitError errcode; + + /* Shut up compiler warning about uninitialized variable. */ + errcode = GIMP_RELOC_INIT_ERROR_NOMEM; + + /* Locate the application's filename. */ + exe = _br_find_exe (&errcode); + if (exe != NULL) + /* Success! */ + return TRUE; + else + { + /* Failed :-( */ + set_gerror (error, errcode); + return FALSE; + } +} + + +/* 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. + * @note Initialization failure is not fatal. BinReloc functions will just + * fallback to the supplied default path. + * + * @returns TRUE on success, FALSE if a filename cannot be found. + */ +gboolean +_gimp_reloc_init_lib (GError **error) +{ + GimpBinrelocInitError errcode; + + /* Shut up compiler warning about uninitialized variable. */ + errcode = GIMP_RELOC_INIT_ERROR_NOMEM; + + exe = _br_find_exe_for_symbol ((const void *) "", &errcode); + if (exe != NULL) + /* Success! */ + return TRUE; + else + { + /* Failed :-( */ + set_gerror (error, errcode); + return exe != NULL; + } +} + +static void +set_gerror (GError **error, GimpBinrelocInitError errcode) +{ + const gchar *error_message; + + if (error == NULL) + return; + + switch (errcode) + { + case GIMP_RELOC_INIT_ERROR_NOMEM: + error_message = "Cannot allocate memory."; + break; + case GIMP_RELOC_INIT_ERROR_OPEN_MAPS: + error_message = "Unable to open /proc/self/maps for reading."; + break; + case GIMP_RELOC_INIT_ERROR_READ_MAPS: + error_message = "Unable to read from /proc/self/maps."; + break; + case GIMP_RELOC_INIT_ERROR_INVALID_MAPS: + error_message = "The file format of /proc/self/maps is invalid."; + break; + case GIMP_RELOC_INIT_ERROR_DISABLED: + error_message = "Binary relocation support is disabled."; + break; + default: + error_message = "Unknown error."; + break; + }; + g_set_error (error, g_quark_from_static_string ("GBinReloc"), + errcode, "%s", error_message); +} + + +/* 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. + */ +gchar * +_gimp_reloc_find_prefix (const gchar *default_prefix) +{ + gchar *dir1, *dir2; + + if (exe == NULL) + { + /* BinReloc not initialized. */ + if (default_prefix != NULL) + return g_strdup (default_prefix); + else + return NULL; + } + + dir1 = g_path_get_dirname (exe); + dir2 = g_path_get_dirname (dir1); + g_free (dir1); + return dir2; +} |