/*

  * BinReloc - a library for creating relocatable executables

  * Written by: Hongli Lai <[email protected]>

  * 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.

  */

 #ifndef __BINRELOC_C__

 #define __BINRELOC_C__

 #ifdef ENABLE_BINRELOC

 	#include <sys/types.h>

 	#include <sys/stat.h>

 	#include <unistd.h>

 #endif /* ENABLE_BINRELOC */

 #include <stdio.h>

 #include <stdlib.h>

 #include <limits.h>

 #include <string.h>

 #include "binreloc.h"

 #ifdef __cplusplus

 extern "C" {

 #endif /* __cplusplus */

 /** @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)

 {

 #ifndef ENABLE_BINRELOC

 	if (error)

 		*error = BR_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 = (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;

 		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;

 #endif /* ENABLE_BINRELOC */

 }

 /** @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)

 {

 #ifndef ENABLE_BINRELOC

 	if (error)

 		*error = BR_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 = 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;

 			address_string = (char *) 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;

 		}

 	}

 	free (address_string);

 	fclose (f);

 	if (found == NULL)

 		return (char *) NULL;

 	else

 		return strdup (found);

 #endif /* ENABLE_BINRELOC */

 }

 #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 *dir2, *result;

 	size_t len;

 	int must_free = 0;

 	len = strlen (dir);

 	if (len > 0 && dir[len - 1] != '/') {

 		dir2 = br_strcat (dir, "/");

 		must_free = 1;

 	} else

 		dir2 = (char *) dir;

 	result = br_strcat (dir2, file);

 	if (must_free)

 		free (dir2);

 	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, end - path + 1);

 	if (result[0] == 0) {

 		free (result);

 		return strdup ("/");

 	} else

 		return result;

 }

 #ifdef __cplusplus

 }

 #endif /* __cplusplus */

 #endif /* __BINRELOC_C__ */