[apple/libc.git] / stdlib / FreeBSD / realpath.c

/*
 * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The names of the authors may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)realpath.c	8.1 (Berkeley) 2/16/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libc/stdlib/realpath.c,v 1.20 2003/05/28 08:23:01 fjoe Exp $");

#include "namespace.h"
#include <sys/param.h>
#include <sys/stat.h>

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "un-namespace.h"

/*
 * char *realpath(const char *path, char resolved[PATH_MAX]);
 *
 * Find the real name of path, by removing all ".", ".." and symlink
 * components.  Returns (resolved) on success, or (NULL) on failure,
 * in which case the path which caused trouble is left in (resolved).
 */
char *
realpath(const char *path, char resolved[PATH_MAX])
{
	struct stat sb;
	char *p, *q, *s;
	size_t left_len, resolved_len;
	unsigned symlinks;
	int serrno, slen;
	char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];

	serrno = errno;
	symlinks = 0;
	if (path[0] == '/') {
		resolved[0] = '/';
		resolved[1] = '\0';
		if (path[1] == '\0')
			return (resolved);
		resolved_len = 1;
		left_len = strlcpy(left, path + 1, sizeof(left));
	} else {
		if (getcwd(resolved, PATH_MAX) == NULL) {
			strlcpy(resolved, ".", PATH_MAX);
			return (NULL);
		}
		resolved_len = strlen(resolved);
		left_len = strlcpy(left, path, sizeof(left));
	}
	if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
		errno = ENAMETOOLONG;
		return (NULL);
	}

	/*
	 * Iterate over path components in `left'.
	 */
	while (left_len != 0) {
		/*
		 * Extract the next path component and adjust `left'
		 * and its length.
		 */
		p = strchr(left, '/');
		s = p ? p : left + left_len;
		if (s - left >= sizeof(next_token)) {
			errno = ENAMETOOLONG;
			return (NULL);
		}
		memcpy(next_token, left, s - left);
		next_token[s - left] = '\0';
		left_len -= s - left;
		if (p != NULL)
			memmove(left, s + 1, left_len + 1);
		if (resolved[resolved_len - 1] != '/') {
			if (resolved_len + 1 >= PATH_MAX) {
				errno = ENAMETOOLONG;
				return (NULL);
			}
			resolved[resolved_len++] = '/';
			resolved[resolved_len] = '\0';
		}
		if (next_token[0] == '\0')
			continue;
		else if (strcmp(next_token, ".") == 0)
			continue;
		else if (strcmp(next_token, "..") == 0) {
			/*
			 * Strip the last path component except when we have
			 * single "/"
			 */
			if (resolved_len > 1) {
				resolved[resolved_len - 1] = '\0';
				q = strrchr(resolved, '/') + 1;
				*q = '\0';
				resolved_len = q - resolved;
			}
			continue;
		}

		/*
		 * Append the next path component and lstat() it. If
		 * lstat() fails we still can return successfully if
		 * there are no more path components left.
		 */
		resolved_len = strlcat(resolved, next_token, PATH_MAX);
		if (resolved_len >= PATH_MAX) {
			errno = ENAMETOOLONG;
			return (NULL);
		}
		if (lstat(resolved, &sb) != 0) {
			if (errno == ENOENT && p == NULL) {
				errno = serrno;
				return (resolved);
			}
			return (NULL);
		}
		if (S_ISLNK(sb.st_mode)) {
			if (symlinks++ > MAXSYMLINKS) {
				errno = ELOOP;
				return (NULL);
			}
			slen = readlink(resolved, symlink, sizeof(symlink) - 1);
			if (slen < 0)
				return (NULL);
			symlink[slen] = '\0';
			if (symlink[0] == '/') {
				resolved[1] = 0;
				resolved_len = 1;
			} else if (resolved_len > 1) {
				/* Strip the last path component. */
				resolved[resolved_len - 1] = '\0';
				q = strrchr(resolved, '/') + 1;
				*q = '\0';
				resolved_len = q - resolved;
			}

			/*
			 * If there are any path components left, then
			 * append them to symlink. The result is placed
			 * in `left'.
			 */
			if (p != NULL) {
				if (symlink[slen - 1] != '/') {
					if (slen + 1 >= sizeof(symlink)) {
						errno = ENAMETOOLONG;
						return (NULL);
					}
					symlink[slen] = '/';
					symlink[slen + 1] = 0;
				}
				left_len = strlcat(symlink, left, sizeof(left));
				if (left_len >= sizeof(left)) {
					errno = ENAMETOOLONG;
					return (NULL);
				}
			}
			left_len = strlcpy(left, symlink, sizeof(left));
		}
	}

	/*
	 * Remove trailing slash except when the resolved pathname
	 * is a single "/".
	 */
	if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
		resolved[resolved_len - 1] = '\0';
	return (resolved);
}
Commit	Line	Data
9385eb3d A	1	/*
	2	* Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
	3	*
	4	* Redistribution and use in source and binary forms, with or without
	5	* modification, are permitted provided that the following conditions
	6	* are met:
	7	* 1. Redistributions of source code must retain the above copyright
	8	* notice, this list of conditions and the following disclaimer.
	9	* 2. Redistributions in binary form must reproduce the above copyright
	10	* notice, this list of conditions and the following disclaimer in the
	11	* documentation and/or other materials provided with the distribution.
	12	* 3. The names of the authors may not be used to endorse or promote
	13	* products derived from this software without specific prior written
	14	* permission.
	15	*
	16	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	17	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	18	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	19	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	20	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	21	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	22	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	23	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	24	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	25	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	26	* SUCH DAMAGE.
	27	*/
	28
	29	#if defined(LIBC_SCCS) && !defined(lint)
	30	static char sccsid[] = "@(#)realpath.c 8.1 (Berkeley) 2/16/94";
	31	#endif /* LIBC_SCCS and not lint */
	32	#include <sys/cdefs.h>
	33	__FBSDID("$FreeBSD: src/lib/libc/stdlib/realpath.c,v 1.20 2003/05/28 08:23:01 fjoe Exp $");
	34
	35	#include "namespace.h"
	36	#include <sys/param.h>
	37	#include <sys/stat.h>
	38
	39	#include <errno.h>
	40	#include <stdlib.h>
	41	#include <string.h>
	42	#include <unistd.h>
	43	#include "un-namespace.h"
	44
	45	/*
	46	* char realpath(const char path, char resolved[PATH_MAX]);
	47	*
	48	* Find the real name of path, by removing all ".", ".." and symlink
	49	* components. Returns (resolved) on success, or (NULL) on failure,
	50	* in which case the path which caused trouble is left in (resolved).
	51	*/
	52	char *
	53	realpath(const char *path, char resolved[PATH_MAX])
	54	{
	55	struct stat sb;
	56	char p, q, *s;
	57	size_t left_len, resolved_len;
	58	unsigned symlinks;
	59	int serrno, slen;
	60	char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
	61
	62	serrno = errno;
	63	symlinks = 0;
	64	if (path[0] == '/') {
65	resolved[0] = '/';
66	resolved[1] = '\0';
67	if (path[1] == '\0')
68	return (resolved);
69	resolved_len = 1;
70	left_len = strlcpy(left, path + 1, sizeof(left));
71	} else {
72	if (getcwd(resolved, PATH_MAX) == NULL) {
73	strlcpy(resolved, ".", PATH_MAX);
74	return (NULL);
75	}
76	resolved_len = strlen(resolved);
77	left_len = strlcpy(left, path, sizeof(left));
78	}
79	if (left_len >= sizeof(left) \|\| resolved_len >= PATH_MAX) {
80	errno = ENAMETOOLONG;
81	return (NULL);
82	}
83
84	/*
85	* Iterate over path components in `left'.
86	*/
87	while (left_len != 0) {
88	/*
89	* Extract the next path component and adjust `left'
90	* and its length.
91	*/
92	p = strchr(left, '/');
93	s = p ? p : left + left_len;
94	if (s - left >= sizeof(next_token)) {
95	errno = ENAMETOOLONG;
96	return (NULL);
97	}
98	memcpy(next_token, left, s - left);
99	next_token[s - left] = '\0';
100	left_len -= s - left;
101	if (p != NULL)
102	memmove(left, s + 1, left_len + 1);
103	if (resolved[resolved_len - 1] != '/') {
104	if (resolved_len + 1 >= PATH_MAX) {
105	errno = ENAMETOOLONG;
106	return (NULL);
107	}
108	resolved[resolved_len++] = '/';
109	resolved[resolved_len] = '\0';
110	}
111	if (next_token[0] == '\0')
112	continue;
113	else if (strcmp(next_token, ".") == 0)
114	continue;
115	else if (strcmp(next_token, "..") == 0) {
116	/*
117	* Strip the last path component except when we have
118	* single "/"
119	*/
120	if (resolved_len > 1) {
121	resolved[resolved_len - 1] = '\0';
122	q = strrchr(resolved, '/') + 1;
123	*q = '\0';
124	resolved_len = q - resolved;
125	}
126	continue;
127	}
128
129	/*
130	* Append the next path component and lstat() it. If
131	* lstat() fails we still can return successfully if
132	* there are no more path components left.
133	*/
134	resolved_len = strlcat(resolved, next_token, PATH_MAX);
135	if (resolved_len >= PATH_MAX) {
136	errno = ENAMETOOLONG;
137	return (NULL);
138	}
139	if (lstat(resolved, &sb) != 0) {
140	if (errno == ENOENT && p == NULL) {
141	errno = serrno;
142	return (resolved);
143	}
144	return (NULL);
145	}
146	if (S_ISLNK(sb.st_mode)) {
147	if (symlinks++ > MAXSYMLINKS) {
148	errno = ELOOP;
149	return (NULL);
150	}
151	slen = readlink(resolved, symlink, sizeof(symlink) - 1);
152	if (slen < 0)
153	return (NULL);
154	symlink[slen] = '\0';
155	if (symlink[0] == '/') {
156	resolved[1] = 0;
157	resolved_len = 1;
158	} else if (resolved_len > 1) {
159	/* Strip the last path component. */
160	resolved[resolved_len - 1] = '\0';
161	q = strrchr(resolved, '/') + 1;
162	*q = '\0';
163	resolved_len = q - resolved;
164	}
165
166	/*
167	* If there are any path components left, then
168	* append them to symlink. The result is placed
169	* in `left'.
170	*/
171	if (p != NULL) {
172	if (symlink[slen - 1] != '/') {
173	if (slen + 1 >= sizeof(symlink)) {
174	errno = ENAMETOOLONG;
175	return (NULL);
176	}
177	symlink[slen] = '/';
178	symlink[slen + 1] = 0;
179	}
180	left_len = strlcat(symlink, left, sizeof(left));
181	if (left_len >= sizeof(left)) {
182	errno = ENAMETOOLONG;
183	return (NULL);
184	}
185	}
186	left_len = strlcpy(left, symlink, sizeof(left));
187	}
188	}
189
190	/*
191	* Remove trailing slash except when the resolved pathname
192	* is a single "/".
193	*/
194	if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
195	resolved[resolved_len - 1] = '\0';
196	return (resolved);
197	}