[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 <sys/mount.h>

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/attr.h>
#include <sys/vnode.h>
#include "un-namespace.h"

struct attrs {
	u_int32_t len;
	attrreference_t name;
	dev_t dev;
	fsobj_type_t type;
	fsobj_id_t id;
	char buf[PATH_MAX];
};

#ifndef BUILDING_VARIANT
__private_extern__ const struct attrlist _rp_alist = {
	ATTR_BIT_MAP_COUNT,
	0,
	ATTR_CMN_NAME | ATTR_CMN_DEVID | ATTR_CMN_OBJTYPE | ATTR_CMN_OBJID,
	0,
	0,
	0,
	0,
};
#else /* BUILDING_VARIANT */
__private_extern__ const struct attrlist _rp_alist;
#endif /* BUILDING_VARIANT */

extern char * __private_getcwd(char *, size_t, int);

/*
 * 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 inresolved[PATH_MAX])
{
	struct attrs attrs;
	struct stat sb;
	char *p, *q, *s;
	size_t left_len, resolved_len, save_resolved_len;
	unsigned symlinks;
	int serrno, slen, useattrs, islink;
	char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
	dev_t dev, lastdev;
	struct statfs sfs;
	static dev_t rootdev;
	static int rootdev_inited = 0;
	ino_t inode;
	char *resolved;

	if (path == NULL) {
		errno = EINVAL;
		return (NULL);
	}
#if __DARWIN_UNIX03
	if (*path == 0) {
		errno = ENOENT;
		return (NULL);
	}
#endif /* __DARWIN_UNIX03 */
	/*
	 * Extension to the standard; if inresolved == NULL, allocate memory
	 */
	if (!inresolved) {
	    if ((resolved = malloc(PATH_MAX)) == NULL) return (NULL);
	} else {
	    resolved = inresolved;
	}
	if (!rootdev_inited) {
		rootdev_inited = 1;
		if (stat("/", &sb) < 0) {
error_return:
			if (!inresolved) {
				int e = errno;
				free(resolved);
				errno = e;
			}
			return (NULL);
		}
		rootdev = sb.st_dev;
	}
	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 !defined(VARIANT_DARWINEXTSN) && __DARWIN_UNIX03
		/* 4447159: don't use GETPATH, so this will fail if */
		/* if parent directories are not readable, as per POSIX */
		if (__private_getcwd(resolved, PATH_MAX, 0) == NULL)
#else /* VARIANT_DARWINEXTSN || !__DARWIN_UNIX03 */
		if (__private_getcwd(resolved, PATH_MAX, 1) == NULL)
#endif /* !VARIANT_DARWINEXTSN && __DARWIN_UNIX03 */
		{
			strlcpy(resolved, ".", PATH_MAX);
			goto error_return;
		}
		resolved_len = strlen(resolved);
		left_len = strlcpy(left, path, sizeof(left));
	}
	if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
		errno = ENAMETOOLONG;
		goto error_return;
	}
	if (resolved_len > 1) {
		if (stat(resolved, &sb) < 0) {
			goto error_return;
		}
		lastdev = sb.st_dev;
	} else
		lastdev = rootdev;

	/*
	 * 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;
			goto error_return;
		}
		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;
				goto error_return;
			}
			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;
		}

		/*
		 * Save resolved_len, so that we can later null out
		 * the the appended next_token, and replace with the
		 * real name (matters on case-insensitive filesystems).
		 */
		save_resolved_len = resolved_len;

		/*
		 * 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;
			goto error_return;
		}
		if (getattrlist(resolved, (void *)&_rp_alist, &attrs, sizeof(attrs), FSOPT_NOFOLLOW) == 0) {
			useattrs = 1;
			islink = (attrs.type == VLNK);
			dev = attrs.dev;
			inode = attrs.id.fid_objno;
		} else if (errno == ENOTSUP || errno == EINVAL) {
			if ((useattrs = lstat(resolved, &sb)) == 0) {
				islink = S_ISLNK(sb.st_mode);
				dev = sb.st_dev;
				inode = sb.st_ino;
			}
		} else
			useattrs = -1;
		if (useattrs < 0) {
#if !__DARWIN_UNIX03
			if (errno == ENOENT && p == NULL) {
				errno = serrno;
				return (resolved);
			}
#endif /* !__DARWIN_UNIX03 */
			goto error_return;
		}
		if (dev != lastdev) {
			/*
			 * We have crossed a mountpoint.  For volumes like UDF
			 * the getattrlist name may not match the actual
			 * mountpoint, so we just copy the mountpoint directly.
			 * (3703138).  However, the mountpoint may not be
			 * accessible, as when chroot-ed, so check first.
			 * There may be a file on the chroot-ed volume with
			 * the same name as the mountpoint, so compare device
			 * and inode numbers.
			 */
			lastdev = dev;
			if (statfs(resolved, &sfs) == 0 && lstat(sfs.f_mntonname, &sb) == 0 && dev == sb.st_dev && inode == sb.st_ino) {
				/*
				 * However, it's possible that the mountpoint
				 * path matches, even though it isn't the real
				 * path in the chroot-ed environment, so check
				 * that each component of the mountpoint
				 * is a directory (and not a symlink)
				 */
				char temp[sizeof(sfs.f_mntonname)];
				char *cp;
				int ok = 1;

				strcpy(temp, sfs.f_mntonname);
				for(;;) {
					if ((cp = strrchr(temp, '/')) == NULL) {
						ok = 0;
						break;
					}
					if (cp <= temp)
						break;
					*cp = 0;
					if (lstat(temp, &sb) < 0 || (sb.st_mode & S_IFMT) != S_IFDIR) {
						ok = 0;
						break;
					}
				}
				if (ok) {
					resolved_len = strlcpy(resolved, sfs.f_mntonname, PATH_MAX);
					continue;
				}
			}
			/* if we fail, use the other methods. */
		}
		if (islink) {
			if (symlinks++ > MAXSYMLINKS) {
				errno = ELOOP;
				goto error_return;
			}
			slen = readlink(resolved, symlink, sizeof(symlink) - 1);
			if (slen < 0) {
				goto error_return;
			}
			symlink[slen] = '\0';
			if (symlink[0] == '/') {
				resolved[1] = 0;
				resolved_len = 1;
				lastdev = rootdev;
			} 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;
						goto error_return;
					}
					symlink[slen] = '/';
					symlink[slen + 1] = 0;
				}
				left_len = strlcat(symlink, left, sizeof(symlink));
				if (left_len >= sizeof(left)) {
					errno = ENAMETOOLONG;
					goto error_return;
				}
			}
			left_len = strlcpy(left, symlink, sizeof(left));
		} else if (useattrs) {
			/*
			 * attrs already has the real name.
			 */

			resolved[save_resolved_len] = '\0';
			resolved_len = strlcat(resolved, (const char *)&attrs.name + attrs.name.attr_dataoffset, PATH_MAX);
			if (resolved_len >= PATH_MAX) {
				errno = ENAMETOOLONG;
				goto error_return;
			}
		}
		/*
		 * For the case of useattrs == 0, we could scan the directory
		 * and try to match the inode.  There are many problems with
		 * this: (1) the directory may not be readable, (2) for multiple
		 * hard links, we would find the first, but not necessarily
		 * the one specified in the path, (3) we can't try to do
		 * a case-insensitive search to match the right one in (2),
		 * because the underlying filesystem may do things like
		 * decompose composed characters.  For most cases, doing
		 * nothing is the right thing when useattrs == 0, so we punt
		 * for now.
		 */
	}

	/*
	 * 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>
ad3c9f2a	38	#include <sys/mount.h>
9385eb3d A	39
	40	#include <errno.h>
	41	#include <stdlib.h>
	42	#include <string.h>
	43	#include <unistd.h>
ad3c9f2a A	44	#include <sys/attr.h>
ad3c9f2a A	45	#include <sys/vnode.h>
9385eb3d A	46	#include "un-namespace.h"
9385eb3d A	47
ad3c9f2a A	48	struct attrs {
	49	u_int32_t len;
	50	attrreference_t name;
	51	dev_t dev;
	52	fsobj_type_t type;
	53	fsobj_id_t id;
	54	char buf[PATH_MAX];
	55	};
	56
	57	#ifndef BUILDING_VARIANT
6465356a	58	__private_extern__ const struct attrlist _rp_alist = {
ad3c9f2a A	59	ATTR_BIT_MAP_COUNT,
	60	0,
	61	ATTR_CMN_NAME \| ATTR_CMN_DEVID \| ATTR_CMN_OBJTYPE \| ATTR_CMN_OBJID,
	62	0,
	63	0,
	64	0,
	65	0,
	66	};
	67	#else /* BUILDING_VARIANT */
6465356a	68	__private_extern__ const struct attrlist _rp_alist;
ad3c9f2a A	69	#endif /* BUILDING_VARIANT */
	70
	71	extern char * __private_getcwd(char *, size_t, int);
	72
9385eb3d A	73	/*
	74	* char realpath(const char path, char resolved[PATH_MAX]);
	75	*
	76	* Find the real name of path, by removing all ".", ".." and symlink
	77	* components. Returns (resolved) on success, or (NULL) on failure,
	78	* in which case the path which caused trouble is left in (resolved).
	79	*/
	80	char *
ad3c9f2a	81	realpath(const char *path, char inresolved[PATH_MAX])
9385eb3d	82	{
ad3c9f2a	83	struct attrs attrs;
9385eb3d A	84	struct stat sb;
9385eb3d A	85	char p, q, *s;
ad3c9f2a	86	size_t left_len, resolved_len, save_resolved_len;
9385eb3d	87	unsigned symlinks;
ad3c9f2a	88	int serrno, slen, useattrs, islink;
9385eb3d	89	char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
ad3c9f2a A	90	dev_t dev, lastdev;
	91	struct statfs sfs;
	92	static dev_t rootdev;
	93	static int rootdev_inited = 0;
	94	ino_t inode;
	95	char *resolved;
9385eb3d	96
ad3c9f2a A	97	if (path == NULL) {
	98	errno = EINVAL;
	99	return (NULL);
	100	}
	101	#if __DARWIN_UNIX03
	102	if (*path == 0) {
	103	errno = ENOENT;
	104	return (NULL);
	105	}
	106	#endif /* __DARWIN_UNIX03 */
	107	/*
	108	* Extension to the standard; if inresolved == NULL, allocate memory
	109	*/
	110	if (!inresolved) {
	111	if ((resolved = malloc(PATH_MAX)) == NULL) return (NULL);
	112	} else {
	113	resolved = inresolved;
	114	}
	115	if (!rootdev_inited) {
	116	rootdev_inited = 1;
	117	if (stat("/", &sb) < 0) {
	118	error_return:
	119	if (!inresolved) {
	120	int e = errno;
	121	free(resolved);
	122	errno = e;
	123	}
	124	return (NULL);
	125	}
	126	rootdev = sb.st_dev;
	127	}
9385eb3d A	128	serrno = errno;
	129	symlinks = 0;
	130	if (path[0] == '/') {
	131	resolved[0] = '/';
	132	resolved[1] = '\0';
ad3c9f2a	133	if (path[1] == '\0') {
9385eb3d	134	return (resolved);
ad3c9f2a	135	}
9385eb3d A	136	resolved_len = 1;
	137	left_len = strlcpy(left, path + 1, sizeof(left));
	138	} else {
ad3c9f2a A	139	#if !defined(VARIANT_DARWINEXTSN) && __DARWIN_UNIX03
	140	/* 4447159: don't use GETPATH, so this will fail if */
	141	/* if parent directories are not readable, as per POSIX */
	142	if (__private_getcwd(resolved, PATH_MAX, 0) == NULL)
	143	#else /* VARIANT_DARWINEXTSN \|\| !__DARWIN_UNIX03 */
	144	if (__private_getcwd(resolved, PATH_MAX, 1) == NULL)
	145	#endif /* !VARIANT_DARWINEXTSN && __DARWIN_UNIX03 */
	146	{
9385eb3d	147	strlcpy(resolved, ".", PATH_MAX);
ad3c9f2a	148	goto error_return;
9385eb3d A	149	}
	150	resolved_len = strlen(resolved);
	151	left_len = strlcpy(left, path, sizeof(left));
	152	}
	153	if (left_len >= sizeof(left) \|\| resolved_len >= PATH_MAX) {
	154	errno = ENAMETOOLONG;
ad3c9f2a	155	goto error_return;
9385eb3d	156	}
ad3c9f2a A	157	if (resolved_len > 1) {
	158	if (stat(resolved, &sb) < 0) {
	159	goto error_return;
	160	}
	161	lastdev = sb.st_dev;
	162	} else
	163	lastdev = rootdev;
9385eb3d A	164
	165	/*
	166	* Iterate over path components in `left'.
	167	*/
	168	while (left_len != 0) {
	169	/*
	170	* Extract the next path component and adjust `left'
	171	* and its length.
	172	*/
	173	p = strchr(left, '/');
	174	s = p ? p : left + left_len;
	175	if (s - left >= sizeof(next_token)) {
	176	errno = ENAMETOOLONG;
ad3c9f2a	177	goto error_return;
9385eb3d A	178	}
	179	memcpy(next_token, left, s - left);
	180	next_token[s - left] = '\0';
	181	left_len -= s - left;
	182	if (p != NULL)
	183	memmove(left, s + 1, left_len + 1);
	184	if (resolved[resolved_len - 1] != '/') {
	185	if (resolved_len + 1 >= PATH_MAX) {
	186	errno = ENAMETOOLONG;
ad3c9f2a	187	goto error_return;
9385eb3d A	188	}
	189	resolved[resolved_len++] = '/';
	190	resolved[resolved_len] = '\0';
	191	}
	192	if (next_token[0] == '\0')
	193	continue;
	194	else if (strcmp(next_token, ".") == 0)
	195	continue;
	196	else if (strcmp(next_token, "..") == 0) {
	197	/*
	198	* Strip the last path component except when we have
	199	* single "/"
	200	*/
	201	if (resolved_len > 1) {
	202	resolved[resolved_len - 1] = '\0';
	203	q = strrchr(resolved, '/') + 1;
	204	*q = '\0';
	205	resolved_len = q - resolved;
	206	}
	207	continue;
	208	}
	209
ad3c9f2a A	210	/*
	211	* Save resolved_len, so that we can later null out
	212	* the the appended next_token, and replace with the
	213	* real name (matters on case-insensitive filesystems).
	214	*/
	215	save_resolved_len = resolved_len;
	216
9385eb3d A	217	/*
	218	* Append the next path component and lstat() it. If
	219	* lstat() fails we still can return successfully if
	220	* there are no more path components left.
	221	*/
	222	resolved_len = strlcat(resolved, next_token, PATH_MAX);
	223	if (resolved_len >= PATH_MAX) {
	224	errno = ENAMETOOLONG;
ad3c9f2a	225	goto error_return;
9385eb3d	226	}
6465356a	227	if (getattrlist(resolved, (void *)&_rp_alist, &attrs, sizeof(attrs), FSOPT_NOFOLLOW) == 0) {
ad3c9f2a A	228	useattrs = 1;
	229	islink = (attrs.type == VLNK);
	230	dev = attrs.dev;
	231	inode = attrs.id.fid_objno;
	232	} else if (errno == ENOTSUP \|\| errno == EINVAL) {
	233	if ((useattrs = lstat(resolved, &sb)) == 0) {
	234	islink = S_ISLNK(sb.st_mode);
	235	dev = sb.st_dev;
	236	inode = sb.st_ino;
	237	}
	238	} else
	239	useattrs = -1;
	240	if (useattrs < 0) {
	241	#if !__DARWIN_UNIX03
9385eb3d A	242	if (errno == ENOENT && p == NULL) {
	243	errno = serrno;
	244	return (resolved);
	245	}
ad3c9f2a A	246	#endif /* !__DARWIN_UNIX03 */
ad3c9f2a A	247	goto error_return;
9385eb3d	248	}
ad3c9f2a A	249	if (dev != lastdev) {
	250	/*
	251	* We have crossed a mountpoint. For volumes like UDF
	252	* the getattrlist name may not match the actual
	253	* mountpoint, so we just copy the mountpoint directly.
	254	* (3703138). However, the mountpoint may not be
	255	* accessible, as when chroot-ed, so check first.
	256	* There may be a file on the chroot-ed volume with
	257	* the same name as the mountpoint, so compare device
	258	* and inode numbers.
	259	*/
	260	lastdev = dev;
	261	if (statfs(resolved, &sfs) == 0 && lstat(sfs.f_mntonname, &sb) == 0 && dev == sb.st_dev && inode == sb.st_ino) {
	262	/*
	263	* However, it's possible that the mountpoint
	264	* path matches, even though it isn't the real
	265	* path in the chroot-ed environment, so check
	266	* that each component of the mountpoint
	267	* is a directory (and not a symlink)
	268	*/
	269	char temp[sizeof(sfs.f_mntonname)];
	270	char *cp;
	271	int ok = 1;
	272
	273	strcpy(temp, sfs.f_mntonname);
	274	for(;;) {
	275	if ((cp = strrchr(temp, '/')) == NULL) {
	276	ok = 0;
	277	break;
	278	}
	279	if (cp <= temp)
	280	break;
	281	*cp = 0;
	282	if (lstat(temp, &sb) < 0 \|\| (sb.st_mode & S_IFMT) != S_IFDIR) {
	283	ok = 0;
	284	break;
	285	}
	286	}
	287	if (ok) {
	288	resolved_len = strlcpy(resolved, sfs.f_mntonname, PATH_MAX);
	289	continue;
	290	}
	291	}
	292	/* if we fail, use the other methods. */
	293	}
	294	if (islink) {
9385eb3d A	295	if (symlinks++ > MAXSYMLINKS) {
9385eb3d A	296	errno = ELOOP;
ad3c9f2a	297	goto error_return;
9385eb3d A	298	}
9385eb3d A	299	slen = readlink(resolved, symlink, sizeof(symlink) - 1);
ad3c9f2a A	300	if (slen < 0) {
	301	goto error_return;
	302	}
9385eb3d A	303	symlink[slen] = '\0';
	304	if (symlink[0] == '/') {
	305	resolved[1] = 0;
	306	resolved_len = 1;
ad3c9f2a	307	lastdev = rootdev;
9385eb3d A	308	} else if (resolved_len > 1) {
	309	/* Strip the last path component. */
	310	resolved[resolved_len - 1] = '\0';
	311	q = strrchr(resolved, '/') + 1;
	312	*q = '\0';
	313	resolved_len = q - resolved;
	314	}
	315
	316	/*
	317	* If there are any path components left, then
	318	* append them to symlink. The result is placed
	319	* in `left'.
	320	*/
	321	if (p != NULL) {
	322	if (symlink[slen - 1] != '/') {
	323	if (slen + 1 >= sizeof(symlink)) {
	324	errno = ENAMETOOLONG;
ad3c9f2a	325	goto error_return;
9385eb3d A	326	}
	327	symlink[slen] = '/';
	328	symlink[slen + 1] = 0;
	329	}
6465356a	330	left_len = strlcat(symlink, left, sizeof(symlink));
9385eb3d A	331	if (left_len >= sizeof(left)) {
9385eb3d A	332	errno = ENAMETOOLONG;
ad3c9f2a	333	goto error_return;
9385eb3d A	334	}
	335	}
	336	left_len = strlcpy(left, symlink, sizeof(left));
ad3c9f2a A	337	} else if (useattrs) {
	338	/*
	339	* attrs already has the real name.
	340	*/
	341
	342	resolved[save_resolved_len] = '\0';
	343	resolved_len = strlcat(resolved, (const char *)&attrs.name + attrs.name.attr_dataoffset, PATH_MAX);
	344	if (resolved_len >= PATH_MAX) {
	345	errno = ENAMETOOLONG;
	346	goto error_return;
	347	}
9385eb3d	348	}
ad3c9f2a A	349	/*
	350	* For the case of useattrs == 0, we could scan the directory
	351	* and try to match the inode. There are many problems with
	352	* this: (1) the directory may not be readable, (2) for multiple
	353	* hard links, we would find the first, but not necessarily
	354	* the one specified in the path, (3) we can't try to do
	355	* a case-insensitive search to match the right one in (2),
	356	* because the underlying filesystem may do things like
	357	* decompose composed characters. For most cases, doing
	358	* nothing is the right thing when useattrs == 0, so we punt
	359	* for now.
	360	*/
9385eb3d A	361	}
	362
	363	/*
	364	* Remove trailing slash except when the resolved pathname
	365	* is a single "/".
	366	*/
	367	if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
	368	resolved[resolved_len - 1] = '\0';
	369	return (resolved);
	370	}