fopen_wrappers.c

/*
   +----------------------------------------------------------------------+
   | PHP Version 7                                                        |
   +----------------------------------------------------------------------+
   | Copyright (c) The PHP Group                                          |
   +----------------------------------------------------------------------+
   | This source file is subject to version 3.01 of the PHP license,      |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.php.net/license/3_01.txt                                  |
   | If you did not receive a copy of the PHP license and are unable to   |
   | obtain it through the world-wide-web, please send a note to          |
   | license@php.net so we can mail you a copy immediately.               |
   +----------------------------------------------------------------------+
   | Authors: Rasmus Lerdorf <rasmus@lerdorf.on.ca>                       |
   |          Jim Winstead <jimw@php.net>                                 |
   +----------------------------------------------------------------------+
 */

/* {{{ includes
 */
#include "php.h"
#include "php_globals.h"
#include "SAPI.h"

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#ifdef PHP_WIN32
#define O_RDONLY _O_RDONLY
#include "win32/param.h"
#else
#include <sys/param.h>
#endif

#include "ext/standard/head.h"
#include "ext/standard/php_standard.h"
#include "zend_compile.h"
#include "php_network.h"

#if HAVE_PWD_H
#include <pwd.h>
#endif

#include <sys/types.h>
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif

#ifdef PHP_WIN32
#include <winsock2.h>
#else
#include <netinet/in.h>
#include <netdb.h>
#if HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#endif

#if defined(PHP_WIN32) || defined(__riscos__)
#undef AF_UNIX
#endif

#if defined(AF_UNIX)
#include <sys/un.h>
#endif
/* }}} */

/* {{{ OnUpdateBaseDir
Allows any change to open_basedir setting in during Startup and Shutdown events,
or a tightening during activation/runtime/deactivation */
PHPAPI ZEND_INI_MH(OnUpdateBaseDir)
{
	char **p, *pathbuf, *ptr, *end;
#ifndef ZTS
	char *base = (char *) mh_arg2;
#else
	char *base = (char *) ts_resource(*((int *) mh_arg2));
#endif

	p = (char **) (base + (size_t) mh_arg1);

	if (stage == PHP_INI_STAGE_STARTUP || stage == PHP_INI_STAGE_SHUTDOWN || stage == PHP_INI_STAGE_ACTIVATE || stage == PHP_INI_STAGE_DEACTIVATE) {
		/* We're in a PHP_INI_SYSTEM context, no restrictions */
		*p = new_value ? ZSTR_VAL(new_value) : NULL;
		return SUCCESS;
	}

	/* Otherwise we're in runtime */
	if (!*p || !**p) {
		/* open_basedir not set yet, go ahead and give it a value */
		*p = ZSTR_VAL(new_value);
		return SUCCESS;
	}

	/* Shortcut: When we have a open_basedir and someone tries to unset, we know it'll fail */
	if (!new_value || !*ZSTR_VAL(new_value)) {
		return FAILURE;
	}

	/* Is the proposed open_basedir at least as restrictive as the current setting? */
	ptr = pathbuf = estrdup(ZSTR_VAL(new_value));
	while (ptr && *ptr) {
		end = strchr(ptr, DEFAULT_DIR_SEPARATOR);
		if (end != NULL) {
			*end = '\0';
			end++;
		}
		if (php_check_open_basedir_ex(ptr, 0) != 0) {
			/* At least one portion of this open_basedir is less restrictive than the prior one, FAIL */
			efree(pathbuf);
			return FAILURE;
		}
		ptr = end;
	}
	efree(pathbuf);

	/* Everything checks out, set it */
	*p = ZSTR_VAL(new_value);

	return SUCCESS;
}
/* }}} */

/* {{{ php_check_specific_open_basedir
	When open_basedir is not NULL, check if the given filename is located in
	open_basedir. Returns -1 if error or not in the open_basedir, else 0.
	When open_basedir is NULL, always return 0.
*/
PHPAPI int php_check_specific_open_basedir(const char *basedir, const char *path)
{
	char resolved_name[MAXPATHLEN];
	char resolved_basedir[MAXPATHLEN];
	char local_open_basedir[MAXPATHLEN];
	char path_tmp[MAXPATHLEN];
	char *path_file;
	size_t resolved_basedir_len;
	size_t resolved_name_len;
	size_t path_len;
	int nesting_level = 0;

	/* Special case basedir==".": Use script-directory */
	if (strcmp(basedir, ".") || !VCWD_GETCWD(local_open_basedir, MAXPATHLEN)) {
		/* Else use the unmodified path */
		strlcpy(local_open_basedir, basedir, sizeof(local_open_basedir));
	}

	path_len = strlen(path);
	if (path_len > (MAXPATHLEN - 1)) {
		/* empty and too long paths are invalid */
		return -1;
	}

	/* normalize and expand path */
	if (expand_filepath(path, resolved_name) == NULL) {
		return -1;
	}

	path_len = strlen(resolved_name);
	memcpy(path_tmp, resolved_name, path_len + 1); /* safe */

	while (VCWD_REALPATH(path_tmp, resolved_name) == NULL) {
#if defined(PHP_WIN32) || defined(HAVE_SYMLINK)
		if (nesting_level == 0) {
			ssize_t ret;
			char buf[MAXPATHLEN];

			ret = php_sys_readlink(path_tmp, buf, MAXPATHLEN - 1);
			if (ret == -1) {
				/* not a broken symlink, move along.. */
			} else {
				/* put the real path into the path buffer */
				memcpy(path_tmp, buf, ret);
				path_tmp[ret] = '\0';
			}
		}
#endif

#ifdef PHP_WIN32
		path_file = strrchr(path_tmp, DEFAULT_SLASH);
		if (!path_file) {
			path_file = strrchr(path_tmp, '/');
		}
#else
		path_file = strrchr(path_tmp, DEFAULT_SLASH);
#endif
		if (!path_file) {
			/* none of the path components exist. definitely not in open_basedir.. */
			return -1;
		} else {
			path_len = path_file - path_tmp + 1;
#ifdef PHP_WIN32
			if (path_len > 1 && path_tmp[path_len - 2] == ':') {
				if (path_len != 3) {
					return -1;
				}
				/* this is c:\ */
				path_tmp[path_len] = '\0';
			} else {
				path_tmp[path_len - 1] = '\0';
			}
#else
			path_tmp[path_len - 1] = '\0';
#endif
		}
		nesting_level++;
	}

	/* Resolve open_basedir to resolved_basedir */
	if (expand_filepath(local_open_basedir, resolved_basedir) != NULL) {
		size_t basedir_len = strlen(basedir);
		/* Handler for basedirs that end with a / */
		resolved_basedir_len = strlen(resolved_basedir);
#ifdef PHP_WIN32
		if (basedir[basedir_len - 1] == PHP_DIR_SEPARATOR || basedir[basedir_len - 1] == '/') {
#else
		if (basedir[basedir_len - 1] == PHP_DIR_SEPARATOR) {
#endif
			if (resolved_basedir[resolved_basedir_len - 1] != PHP_DIR_SEPARATOR) {
				resolved_basedir[resolved_basedir_len] = PHP_DIR_SEPARATOR;
				resolved_basedir[++resolved_basedir_len] = '\0';
			}
		} else {
				resolved_basedir[resolved_basedir_len++] = PHP_DIR_SEPARATOR;
				resolved_basedir[resolved_basedir_len] = '\0';
		}

		resolved_name_len = strlen(resolved_name);
		if (path_tmp[path_len - 1] == PHP_DIR_SEPARATOR) {
			if (resolved_name[resolved_name_len - 1] != PHP_DIR_SEPARATOR) {
				resolved_name[resolved_name_len] = PHP_DIR_SEPARATOR;
				resolved_name[++resolved_name_len] = '\0';
			}
		}

		/* Check the path */
#ifdef PHP_WIN32
		if (strncasecmp(resolved_basedir, resolved_name, resolved_basedir_len) == 0) {
#else
		if (strncmp(resolved_basedir, resolved_name, resolved_basedir_len) == 0) {
#endif
			if (resolved_name_len > resolved_basedir_len &&
				resolved_name[resolved_basedir_len - 1] != PHP_DIR_SEPARATOR) {
				return -1;
			} else {
				/* File is in the right directory */
				return 0;
			}
		} else {
			/* /openbasedir/ and /openbasedir are the same directory */
			if (resolved_basedir_len == (resolved_name_len + 1) && resolved_basedir[resolved_basedir_len - 1] == PHP_DIR_SEPARATOR) {
#ifdef PHP_WIN32
				if (strncasecmp(resolved_basedir, resolved_name, resolved_name_len) == 0) {
#else
				if (strncmp(resolved_basedir, resolved_name, resolved_name_len) == 0) {
#endif
					return 0;
				}
			}
			return -1;
		}
	} else {
		/* Unable to resolve the real path, return -1 */
		return -1;
	}
}
/* }}} */

PHPAPI int php_check_open_basedir(const char *path)
{
	return php_check_open_basedir_ex(path, 1);
}

/* {{{ php_check_open_basedir
 */
PHPAPI int php_check_open_basedir_ex(const char *path, int warn)
{
	/* Only check when open_basedir is available */
	if (PG(open_basedir) && *PG(open_basedir)) {
		char *pathbuf;
		char *ptr;
		char *end;

		/* Check if the path is too long so we can give a more useful error
		* message. */
		if (strlen(path) > (MAXPATHLEN - 1)) {
			php_error_docref(NULL, E_WARNING, "File name is longer than the maximum allowed path length on this platform (%d): %s", MAXPATHLEN, path);
			errno = EINVAL;
			return -1;
		}

		pathbuf = estrdup(PG(open_basedir));

		ptr = pathbuf;

		while (ptr && *ptr) {
			end = strchr(ptr, DEFAULT_DIR_SEPARATOR);
			if (end != NULL) {
				*end = '\0';
				end++;
			}

			if (php_check_specific_open_basedir(ptr, path) == 0) {
				efree(pathbuf);
				return 0;
			}

			ptr = end;
		}
		if (warn) {
			php_error_docref(NULL, E_WARNING, "open_basedir restriction in effect. File(%s) is not within the allowed path(s): (%s)", path, PG(open_basedir));
		}
		efree(pathbuf);
		errno = EPERM; /* we deny permission to open it */
		return -1;
	}

	/* Nothing to check... */
	return 0;
}
/* }}} */

/* {{{ php_fopen_and_set_opened_path
 */
static FILE *php_fopen_and_set_opened_path(const char *path, const char *mode, zend_string **opened_path)
{
	FILE *fp;

	if (php_check_open_basedir((char *)path)) {
		return NULL;
	}
	fp = VCWD_FOPEN(path, mode);
	if (fp && opened_path) {
		//TODO :avoid reallocation
		char *tmp = expand_filepath_with_mode(path, NULL, NULL, 0, CWD_EXPAND);
		if (tmp) {
			*opened_path = zend_string_init(tmp, strlen(tmp), 0);
			efree(tmp);
		}
	}
	return fp;
}
/* }}} */

/* {{{ php_fopen_primary_script
 */
PHPAPI int php_fopen_primary_script(zend_file_handle *file_handle)
{
	char *path_info;
	char *filename = NULL;
	zend_string *resolved_path = NULL;
	size_t length;
	zend_bool orig_display_errors;

	path_info = SG(request_info).request_uri;
#if HAVE_PWD_H
	if (PG(user_dir) && *PG(user_dir) && path_info && '/' == path_info[0] && '~' == path_info[1]) {
		char *s = strchr(path_info + 2, '/');

		if (s) {			/* if there is no path name after the file, do not bother */
			char user[32];			/* to try open the directory */
			struct passwd *pw;
#if defined(ZTS) && defined(HAVE_GETPWNAM_R) && defined(_SC_GETPW_R_SIZE_MAX)
			struct passwd pwstruc;
			long pwbuflen = sysconf(_SC_GETPW_R_SIZE_MAX);
			char *pwbuf;

			if (pwbuflen < 1) {
				return FAILURE;
			}

			pwbuf = emalloc(pwbuflen);
#endif
			length = s - (path_info + 2);
			if (length > sizeof(user) - 1) {
				length = sizeof(user) - 1;
			}
			memcpy(user, path_info + 2, length);
			user[length] = '\0';
#if defined(ZTS) && defined(HAVE_GETPWNAM_R) && defined(_SC_GETPW_R_SIZE_MAX)
			if (getpwnam_r(user, &pwstruc, pwbuf, pwbuflen, &pw)) {
				efree(pwbuf);
				return FAILURE;
			}
#else
			pw = getpwnam(user);
#endif
			if (pw && pw->pw_dir) {
				spprintf(&filename, 0, "%s%c%s%c%s", pw->pw_dir, PHP_DIR_SEPARATOR, PG(user_dir), PHP_DIR_SEPARATOR, s + 1); /* Safe */
			} else {
				filename = SG(request_info).path_translated;
			}
#if defined(ZTS) && defined(HAVE_GETPWNAM_R) && defined(_SC_GETPW_R_SIZE_MAX)
			efree(pwbuf);
#endif
		}
	} else
#endif
	if (PG(doc_root) && path_info && (length = strlen(PG(doc_root))) &&
		IS_ABSOLUTE_PATH(PG(doc_root), length)) {
		size_t path_len = strlen(path_info);
		filename = emalloc(length + path_len + 2);
		memcpy(filename, PG(doc_root), length);
		if (!IS_SLASH(filename[length - 1])) {	/* length is never 0 */
			filename[length++] = PHP_DIR_SEPARATOR;
		}
		if (IS_SLASH(path_info[0])) {
			length--;
		}
		strncpy(filename + length, path_info, path_len + 1);
	} else {
		filename = SG(request_info).path_translated;
	}


	if (filename) {
		resolved_path = zend_resolve_path(filename, strlen(filename));
	}

	if (!resolved_path) {
		if (SG(request_info).path_translated != filename) {
			if (filename) {
				efree(filename);
			}
		}
		/* we have to free SG(request_info).path_translated here because
		 * php_destroy_request_info assumes that it will get
		 * freed when the include_names hash is emptied, but
		 * we're not adding it in this case */
		if (SG(request_info).path_translated) {
			efree(SG(request_info).path_translated);
			SG(request_info).path_translated = NULL;
		}
		return FAILURE;
	}
	zend_string_release_ex(resolved_path, 0);

	orig_display_errors = PG(display_errors);
	PG(display_errors) = 0;
	if (zend_stream_open(filename, file_handle) == FAILURE) {
		PG(display_errors) = orig_display_errors;
		if (SG(request_info).path_translated != filename) {
			if (filename) {
				efree(filename);
			}
		}
		if (SG(request_info).path_translated) {
			efree(SG(request_info).path_translated);
			SG(request_info).path_translated = NULL;
		}
		return FAILURE;
	}
	PG(display_errors) = orig_display_errors;

	if (SG(request_info).path_translated != filename) {
		if (SG(request_info).path_translated) {
			efree(SG(request_info).path_translated);
		}
		SG(request_info).path_translated = filename;
	}

	return SUCCESS;
}
/* }}} */

/* {{{ php_resolve_path
 * Returns the realpath for given filename according to include path
 */
PHPAPI zend_string *php_resolve_path(const char *filename, size_t filename_length, const char *path)
{
	char resolved_path[MAXPATHLEN];
	char trypath[MAXPATHLEN];
	const char *ptr, *end, *p;
	const char *actual_path;
	php_stream_wrapper *wrapper;
	zend_string *exec_filename;

	if (!filename || CHECK_NULL_PATH(filename, filename_length)) {
		return NULL;
	}

	/* Don't resolve paths which contain protocol (except of file://) */
	for (p = filename; isalnum((int)*p) || *p == '+' || *p == '-' || *p == '.'; p++);
	if ((*p == ':') && (p - filename > 1) && (p[1] == '/') && (p[2] == '/')) {
		wrapper = php_stream_locate_url_wrapper(filename, &actual_path, STREAM_OPEN_FOR_INCLUDE);
		if (wrapper == &php_plain_files_wrapper) {
			if (tsrm_realpath(actual_path, resolved_path)) {
				return zend_string_init(resolved_path, strlen(resolved_path), 0);
			}
		}
		return NULL;
	}

	if ((*filename == '.' &&
	     (IS_SLASH(filename[1]) ||
	      ((filename[1] == '.') && IS_SLASH(filename[2])))) ||
	    IS_ABSOLUTE_PATH(filename, filename_length) ||
#ifdef PHP_WIN32
		/* This should count as an absolute local path as well, however
		   IS_ABSOLUTE_PATH doesn't care about this path form till now. It
		   might be a big thing to extend, thus just a local handling for
		   now. */
		filename_length >=2 && IS_SLASH(filename[0]) && !IS_SLASH(filename[1]) ||
#endif
	    !path ||
	    !*path) {
		if (tsrm_realpath(filename, resolved_path)) {
			return zend_string_init(resolved_path, strlen(resolved_path), 0);
		} else {
			return NULL;
		}
	}

	ptr = path;
	while (ptr && *ptr) {
		/* Check for stream wrapper */
		int is_stream_wrapper = 0;

		for (p = ptr; isalnum((int)*p) || *p == '+' || *p == '-' || *p == '.'; p++);
		if ((*p == ':') && (p - ptr > 1) && (p[1] == '/') && (p[2] == '/')) {
			/* .:// or ..:// is not a stream wrapper */
			if (p[-1] != '.' || p[-2] != '.' || p - 2 != ptr) {
				p += 3;
				is_stream_wrapper = 1;
			}
		}
		end = strchr(p, DEFAULT_DIR_SEPARATOR);
		if (end) {
			if (filename_length > (MAXPATHLEN - 2) || (end-ptr) > MAXPATHLEN || (end-ptr) + 1 + filename_length + 1 >= MAXPATHLEN) {
				ptr = end + 1;
				continue;
			}
			memcpy(trypath, ptr, end-ptr);
			trypath[end-ptr] = '/';
			memcpy(trypath+(end-ptr)+1, filename, filename_length+1);
			ptr = end+1;
		} else {
			size_t len = strlen(ptr);

			if (filename_length > (MAXPATHLEN - 2) || len > MAXPATHLEN || len + 1 + filename_length + 1 >= MAXPATHLEN) {
				break;
			}
			memcpy(trypath, ptr, len);
			trypath[len] = '/';
			memcpy(trypath+len+1, filename, filename_length+1);
			ptr = NULL;
		}
		actual_path = trypath;
		if (is_stream_wrapper) {
			wrapper = php_stream_locate_url_wrapper(trypath, &actual_path, STREAM_OPEN_FOR_INCLUDE);
			if (!wrapper) {
				continue;
			} else if (wrapper != &php_plain_files_wrapper) {
				if (wrapper->wops->url_stat) {
					php_stream_statbuf ssb;

					if (SUCCESS == wrapper->wops->url_stat(wrapper, trypath, 0, &ssb, NULL)) {
						return zend_string_init(trypath, strlen(trypath), 0);
					}
				}
				continue;
			}
		}
		if (tsrm_realpath(actual_path, resolved_path)) {
			return zend_string_init(resolved_path, strlen(resolved_path), 0);
		}
	} /* end provided path */

	/* check in calling scripts' current working directory as a fall back case
	 */
	if (zend_is_executing() &&
	    (exec_filename = zend_get_executed_filename_ex()) != NULL) {
		const char *exec_fname = ZSTR_VAL(exec_filename);
		size_t exec_fname_length = ZSTR_LEN(exec_filename);

		while ((--exec_fname_length < SIZE_MAX) && !IS_SLASH(exec_fname[exec_fname_length]));
		if (exec_fname_length > 0 &&
			filename_length < (MAXPATHLEN - 2) &&
		    exec_fname_length + 1 + filename_length + 1 < MAXPATHLEN) {
			memcpy(trypath, exec_fname, exec_fname_length + 1);
			memcpy(trypath+exec_fname_length + 1, filename, filename_length+1);
			actual_path = trypath;

			/* Check for stream wrapper */
			for (p = trypath; isalnum((int)*p) || *p == '+' || *p == '-' || *p == '.'; p++);
			if ((*p == ':') && (p - trypath > 1) && (p[1] == '/') && (p[2] == '/')) {
				wrapper = php_stream_locate_url_wrapper(trypath, &actual_path, STREAM_OPEN_FOR_INCLUDE);
				if (!wrapper) {
					return NULL;
				} else if (wrapper != &php_plain_files_wrapper) {
					if (wrapper->wops->url_stat) {
						php_stream_statbuf ssb;

						if (SUCCESS == wrapper->wops->url_stat(wrapper, trypath, 0, &ssb, NULL)) {
							return zend_string_init(trypath, strlen(trypath), 0);
						}
					}
					return NULL;
				}
			}

			if (tsrm_realpath(actual_path, resolved_path)) {
				return zend_string_init(resolved_path, strlen(resolved_path), 0);
			}
		}
	}

	return NULL;
}
/* }}} */

/* {{{ php_fopen_with_path
 * Tries to open a file with a PATH-style list of directories.
 * If the filename starts with "." or "/", the path is ignored.
 */
PHPAPI FILE *php_fopen_with_path(const char *filename, const char *mode, const char *path, zend_string **opened_path)
{
	char *pathbuf, *ptr, *end;
	char trypath[MAXPATHLEN];
	FILE *fp;
	size_t filename_length;
	zend_string *exec_filename;

	if (opened_path) {
		*opened_path = NULL;
	}

	if (!filename) {
		return NULL;
	}

	filename_length = strlen(filename);
#ifndef PHP_WIN32
	(void) filename_length;
#endif

	/* Relative path open */
	if ((*filename == '.')
	/* Absolute path open */
	 || IS_ABSOLUTE_PATH(filename, filename_length)
	 || (!path || !*path)
	) {
		return php_fopen_and_set_opened_path(filename, mode, opened_path);
	}

	/* check in provided path */
	/* append the calling scripts' current working directory
	 * as a fall back case
	 */
	if (zend_is_executing() &&
	    (exec_filename = zend_get_executed_filename_ex()) != NULL) {
		const char *exec_fname = ZSTR_VAL(exec_filename);
		size_t exec_fname_length = ZSTR_LEN(exec_filename);

		while ((--exec_fname_length < SIZE_MAX) && !IS_SLASH(exec_fname[exec_fname_length]));
		if ((exec_fname && exec_fname[0] == '[') || exec_fname_length <= 0) {
			/* [no active file] or no path */
			pathbuf = estrdup(path);
		} else {
			size_t path_length = strlen(path);

			pathbuf = (char *) emalloc(exec_fname_length + path_length + 1 + 1);
			memcpy(pathbuf, path, path_length);
			pathbuf[path_length] = DEFAULT_DIR_SEPARATOR;
			memcpy(pathbuf + path_length + 1, exec_fname, exec_fname_length);
			pathbuf[path_length + exec_fname_length + 1] = '\0';
		}
	} else {
		pathbuf = estrdup(path);
	}

	ptr = pathbuf;

	while (ptr && *ptr) {
		end = strchr(ptr, DEFAULT_DIR_SEPARATOR);
		if (end != NULL) {
			*end = '\0';
			end++;
		}
		if (snprintf(trypath, MAXPATHLEN, "%s/%s", ptr, filename) >= MAXPATHLEN) {
			php_error_docref(NULL, E_NOTICE, "%s/%s path was truncated to %d", ptr, filename, MAXPATHLEN);
		}
		fp = php_fopen_and_set_opened_path(trypath, mode, opened_path);
		if (fp) {
			efree(pathbuf);
			return fp;
		}
		ptr = end;
	} /* end provided path */

	efree(pathbuf);
	return NULL;
}
/* }}} */

/* {{{ php_strip_url_passwd
 */
PHPAPI char *php_strip_url_passwd(char *url)
{
	register char *p, *url_start;

	if (url == NULL) {
		return "";
	}

	p = url;

	while (*p) {
		if (*p == ':' && *(p + 1) == '/' && *(p + 2) == '/') {
			/* found protocol */
			url_start = p = p + 3;

			while (*p) {
				if (*p == '@') {
					int i;

					for (i = 0; i < 3 && url_start < p; i++, url_start++) {
						*url_start = '.';
					}
					for (; *p; p++) {
						*url_start++ = *p;
					}
					*url_start=0;
					break;
				}
				p++;
			}
			return url;
		}
		p++;
	}
	return url;
}
/* }}} */

/* {{{ expand_filepath
 */
PHPAPI char *expand_filepath(const char *filepath, char *real_path)
{
	return expand_filepath_ex(filepath, real_path, NULL, 0);
}
/* }}} */

/* {{{ expand_filepath_ex
 */
PHPAPI char *expand_filepath_ex(const char *filepath, char *real_path, const char *relative_to, size_t relative_to_len)
{
	return expand_filepath_with_mode(filepath, real_path, relative_to, relative_to_len, CWD_FILEPATH);
}
/* }}} */

/* {{{ expand_filepath_use_realpath
 */
PHPAPI char *expand_filepath_with_mode(const char *filepath, char *real_path, const char *relative_to, size_t relative_to_len, int realpath_mode)
{
	cwd_state new_state;
	char cwd[MAXPATHLEN];
	size_t copy_len;
	size_t path_len;

	if (!filepath[0]) {
		return NULL;
	}

	path_len = strlen(filepath);

	if (IS_ABSOLUTE_PATH(filepath, path_len)) {
		cwd[0] = '\0';
	} else {
		const char *iam = SG(request_info).path_translated;
		const char *result;
		if (relative_to) {
			if (relative_to_len > MAXPATHLEN-1U) {
				return NULL;
			}
			result = relative_to;
			memcpy(cwd, relative_to, relative_to_len+1U);
		} else {
			result = VCWD_GETCWD(cwd, MAXPATHLEN);
		}

		if (!result && (iam != filepath)) {
			int fdtest = -1;

			fdtest = VCWD_OPEN(filepath, O_RDONLY);
			if (fdtest != -1) {
				/* return a relative file path if for any reason
				 * we cannot cannot getcwd() and the requested,
				 * relatively referenced file is accessible */
				copy_len = path_len > MAXPATHLEN - 1 ? MAXPATHLEN - 1 : path_len;
				if (real_path) {
					memcpy(real_path, filepath, copy_len);
					real_path[copy_len] = '\0';
				} else {
					real_path = estrndup(filepath, copy_len);
				}
				close(fdtest);
				return real_path;
			} else {
				cwd[0] = '\0';
			}
		} else if (!result) {
			cwd[0] = '\0';
		}
	}

	new_state.cwd = estrdup(cwd);
	new_state.cwd_length = strlen(cwd);

	if (virtual_file_ex(&new_state, filepath, NULL, realpath_mode)) {
		efree(new_state.cwd);
		return NULL;
	}

	if (real_path) {
		copy_len = new_state.cwd_length > MAXPATHLEN - 1 ? MAXPATHLEN - 1 : new_state.cwd_length;
		memcpy(real_path, new_state.cwd, copy_len);
		real_path[copy_len] = '\0';
	} else {
		real_path = estrndup(new_state.cwd, new_state.cwd_length);
	}
	efree(new_state.cwd);

	return real_path;
}
/* }}} */