gimp/libgimpbase/gimpreloc.c

436 lines
11 KiB
C

/*
* 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;
}