[apple/libc.git] / gen / FreeBSD / getcwd.c

/*
 * Copyright (c) 1989, 1991, 1993, 1995
 *	The Regents of the University of California.  All rights reserved.
 *
 * 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.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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[] = "@(#)getcwd.c	8.5 (Berkeley) 2/7/95";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libc/gen/getcwd.c,v 1.29 2007/01/09 00:27:53 imp Exp $");

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

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

#define	ISDOT(dp) \
	(dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
	    (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))

/*
 * If __getcwd() ever becomes a syscall, we can remove this workaround.
 * The problem here is that fcntl() assumes a buffer of size MAXPATHLEN,
 * if size is less than MAXPATHLEN, we need to use a temporary buffer
 * and see if it fits.  We also have to assume that open() or fcntl()
 * don't fail with errno=ERANGE.
 */
static inline int
__getcwd(char *buf, size_t size)
{
	int fd, err, save;
	struct stat dot, pt;
	char *b;

	if ((fd = open(".", O_RDONLY)) < 0)
		return -1;
	if (fstat(fd, &dot) < 0) {
		save = errno;
		close(fd);
		errno = save;
		return -1;
	}
	/* check that the device and inode are non-zero, otherwise punt */
	if (dot.st_dev == 0 || dot.st_ino == 0) {
		close(fd);
		errno = EINVAL;
		return -1;
	}
	if (size < MAXPATHLEN) {
		/* the hard case; allocate a buffer of size MAXPATHLEN to use */
		b = (char *)alloca(MAXPATHLEN);
		if (b == NULL) {
			close(fd);
			errno = ENOMEM; /* make sure it isn't ERANGE */
			return -1;
		}
	} else
		b = buf;

	err = fcntl(fd, F_GETPATH, b);
	if (err) {
		save = errno;
		close(fd);
		errno = save;
		return err;
	}
	close(fd);
	/*
	 * now double-check that the path returned by fcntl() has the same
	 * device and inode number as '.'.
	 */
	if (stat(b, &pt) < 0)
		return -1;
	/*
	 * Since dot.st_dev and dot.st_ino are non-zero, we don't need to
	 * separately test for pt.st_dev and pt.st_ino being non-zero, because
	 * they have to match
	 */
	if (dot.st_dev != pt.st_dev || dot.st_ino != pt.st_ino) {
		errno = EINVAL;
		return -1;
	}
	/*
	 * For the case where we allocated a buffer, check that it can fit
	 * in the real buffer, and copy it over.
	 */
	if (size < MAXPATHLEN) {
		if (strlen(b) >= size) {
			errno = ERANGE;
			return -1;
		}
		strcpy(buf, b);
	}
	return 0;
}

__private_extern__ char *
__private_getcwd(pt, size, usegetpath)
	char *pt;
	size_t size;
	int usegetpath;
{
	struct dirent *dp;
	DIR *dir = NULL;
	dev_t dev;
	ino_t ino;
	int first;
	char *bpt, *bup;
	struct stat s;
	dev_t root_dev;
	ino_t root_ino;
	size_t ptsize, upsize;
	int save_errno;
	char *ept, *eup, *up, c;

	/*
	 * If no buffer specified by the user, allocate one as necessary.
	 * If a buffer is specified, the size has to be non-zero.  The path
	 * is built from the end of the buffer backwards.
	 */
	if (pt) {
		ptsize = 0;
		if (!size) {
			errno = EINVAL;
			return (NULL);
		}
		if (size == 1) {
			errno = ERANGE;
			return (NULL);
		}
		ept = pt + size;
	} else {
		if ((pt = malloc(ptsize = MAXPATHLEN)) == NULL)
			return (NULL);
		ept = pt + ptsize;
	}
	if (usegetpath) {
		if (__getcwd(pt, ept - pt) == 0) {
			return (pt);
		} else if (errno == ERANGE) /* failed because buffer too small */
			return NULL;
	}
	bpt = ept - 1;
	*bpt = '\0';

	/*
	 * Allocate MAXPATHLEN bytes for the string of "../"'s.
	 * Should always be enough.  If it's not, allocate
	 * as necessary.  Special case the first stat, it's ".", not "..".
	 */
	if ((up = malloc(upsize = MAXPATHLEN)) == NULL)
		goto err;
	eup = up + MAXPATHLEN;
	bup = up;
	up[0] = '.';
	up[1] = '\0';

	/* Save root values, so know when to stop. */
	if (stat("/", &s))
		goto err;
	root_dev = s.st_dev;
	root_ino = s.st_ino;

	errno = 0;			/* XXX readdir has no error return. */

	for (first = 1;; first = 0) {
		/* Stat the current level. */
		if (lstat(up, &s))
			goto err;

		/* Save current node values. */
		ino = s.st_ino;
		dev = s.st_dev;

		/* Check for reaching root. */
		if (root_dev == dev && root_ino == ino) {
			*--bpt = '/';
			/*
			 * It's unclear that it's a requirement to copy the
			 * path to the beginning of the buffer, but it's always
			 * been that way and stuff would probably break.
			 */
			bcopy(bpt, pt, ept - bpt);
			free(up);
			return (pt);
		}

		/*
		 * Build pointer to the parent directory, allocating memory
		 * as necessary.  Max length is 3 for "../", the largest
		 * possible component name, plus a trailing NUL.
		 */
		while (bup + 3  + MAXNAMLEN + 1 >= eup) {
			if ((up = reallocf(up, upsize *= 2)) == NULL)
				goto err;
			bup = up;
			eup = up + upsize;
		}
		*bup++ = '.';
		*bup++ = '.';
		*bup = '\0';

		/* Open and stat parent directory. */
		if (!(dir = opendir(up)) || _fstat(dirfd(dir), &s))
			goto err;

		/* Add trailing slash for next directory. */
		*bup++ = '/';
		*bup = '\0';

		/*
		 * If it's a mount point, have to stat each element because
		 * the inode number in the directory is for the entry in the
		 * parent directory, not the inode number of the mounted file.
		 */
		save_errno = 0;
		if (s.st_dev == dev) {
			for (;;) {
				if (!(dp = readdir(dir)))
					goto notfound;
				if (dp->d_fileno == ino)
					break;
			}
		} else
			for (;;) {
				if (!(dp = readdir(dir)))
					goto notfound;
				if (ISDOT(dp))
					continue;
				bcopy(dp->d_name, bup, dp->d_namlen + 1);

				/* Save the first error for later. */
				if (lstat(up, &s)) {
					if (!save_errno)
						save_errno = errno;
					errno = 0;
					continue;
				}
				if (s.st_dev == dev && s.st_ino == ino)
					break;
			}

		/*
		 * Check for length of the current name, preceding slash,
		 * leading slash.
		 */
		while (bpt - pt < dp->d_namlen + (first ? 1 : 2)) {
			size_t len, off;

			if (!ptsize) {
				errno = ERANGE;
				goto err;
			}
			off = bpt - pt;
			len = ept - bpt;
			if ((pt = reallocf(pt, ptsize *= 2)) == NULL)
				goto err;
			bpt = pt + off;
			ept = pt + ptsize;
			bcopy(bpt, ept - len, len);
			bpt = ept - len;
		}
		if (!first)
			*--bpt = '/';
		bpt -= dp->d_namlen;
		bcopy(dp->d_name, bpt, dp->d_namlen);
		(void) closedir(dir);
		dir = NULL;

		/* Truncate any file name. */
		*bup = '\0';
	}

notfound:
	/*
	 * If readdir set errno, use it, not any saved error; otherwise,
	 * didn't find the current directory in its parent directory, set
	 * errno to ENOENT.
	 */
	if (!errno)
		errno = save_errno ? save_errno : ENOENT;
	/* FALLTHROUGH */
err:
	save_errno = errno;

	if (ptsize)
		free(pt);
	if (dir)
		(void) closedir(dir);
	free(up);

	errno = save_errno;
	return (NULL);
}

char *
getcwd(pt, size)
	char *pt;
	size_t size;
{
	return __private_getcwd(pt, size, 1);
}
Commit	Line	Data
e9ce8d39	1	/*
9385eb3d	2	* Copyright (c) 1989, 1991, 1993, 1995
e9ce8d39 A	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
e9ce8d39 A	13	* 4. Neither the name of the University nor the names of its contributors
	14	* may be used to endorse or promote products derived from this software
	15	* without specific prior written permission.
	16	*
	17	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	18	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	19	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	20	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	21	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	22	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	23	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	24	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	25	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	26	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	27	* SUCH DAMAGE.
	28	*/
	29
9385eb3d A	30	#if defined(LIBC_SCCS) && !defined(lint)
	31	static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95";
	32	#endif /* LIBC_SCCS and not lint */
	33	#include <sys/cdefs.h>
1f2f436a	34	__FBSDID("$FreeBSD: src/lib/libc/gen/getcwd.c,v 1.29 2007/01/09 00:27:53 imp Exp $");
e9ce8d39	35
9385eb3d	36	#include "namespace.h"
e9ce8d39 A	37	#include <sys/param.h>
	38	#include <sys/stat.h>
	39
	40	#include <dirent.h>
	41	#include <errno.h>
	42	#include <fcntl.h>
	43	#include <stdio.h>
	44	#include <stdlib.h>
	45	#include <string.h>
	46	#include <unistd.h>
9385eb3d	47	#include "un-namespace.h"
e9ce8d39 A	48
	49	#define ISDOT(dp) \
	50	(dp->d_name[0] == '.' && (dp->d_name[1] == '\0' \|\| \
9385eb3d A	51	(dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
9385eb3d A	52
ad3c9f2a A	53	/*
	54	* If __getcwd() ever becomes a syscall, we can remove this workaround.
	55	* The problem here is that fcntl() assumes a buffer of size MAXPATHLEN,
	56	* if size is less than MAXPATHLEN, we need to use a temporary buffer
	57	* and see if it fits. We also have to assume that open() or fcntl()
	58	* don't fail with errno=ERANGE.
	59	*/
	60	static inline int
	61	__getcwd(char *buf, size_t size)
	62	{
	63	int fd, err, save;
	64	struct stat dot, pt;
	65	char *b;
e9ce8d39	66
ad3c9f2a A	67	if ((fd = open(".", O_RDONLY)) < 0)
	68	return -1;
	69	if (fstat(fd, &dot) < 0) {
	70	save = errno;
	71	close(fd);
	72	errno = save;
	73	return -1;
	74	}
	75	/* check that the device and inode are non-zero, otherwise punt */
	76	if (dot.st_dev == 0 \|\| dot.st_ino == 0) {
	77	close(fd);
	78	errno = EINVAL;
	79	return -1;
	80	}
	81	if (size < MAXPATHLEN) {
	82	/* the hard case; allocate a buffer of size MAXPATHLEN to use */
	83	b = (char *)alloca(MAXPATHLEN);
	84	if (b == NULL) {
	85	close(fd);
	86	errno = ENOMEM; /* make sure it isn't ERANGE */
	87	return -1;
	88	}
	89	} else
	90	b = buf;
	91
	92	err = fcntl(fd, F_GETPATH, b);
	93	if (err) {
	94	save = errno;
	95	close(fd);
	96	errno = save;
	97	return err;
	98	}
	99	close(fd);
	100	/*
	101	* now double-check that the path returned by fcntl() has the same
	102	* device and inode number as '.'.
	103	*/
	104	if (stat(b, &pt) < 0)
	105	return -1;
	106	/*
	107	* Since dot.st_dev and dot.st_ino are non-zero, we don't need to
	108	* separately test for pt.st_dev and pt.st_ino being non-zero, because
	109	* they have to match
	110	*/
	111	if (dot.st_dev != pt.st_dev \|\| dot.st_ino != pt.st_ino) {
	112	errno = EINVAL;
	113	return -1;
	114	}
	115	/*
	116	* For the case where we allocated a buffer, check that it can fit
	117	* in the real buffer, and copy it over.
	118	*/
	119	if (size < MAXPATHLEN) {
	120	if (strlen(b) >= size) {
	121	errno = ERANGE;
	122	return -1;
	123	}
	124	strcpy(buf, b);
	125	}
	126	return 0;
	127	}
	128
	129	__private_extern__ char *
	130	__private_getcwd(pt, size, usegetpath)
e9ce8d39 A	131	char *pt;
e9ce8d39 A	132	size_t size;
ad3c9f2a	133	int usegetpath;
e9ce8d39	134	{
9385eb3d A	135	struct dirent *dp;
9385eb3d A	136	DIR *dir = NULL;
e9ce8d39 A	137	dev_t dev;
e9ce8d39 A	138	ino_t ino;
9385eb3d A	139	int first;
9385eb3d A	140	char bpt, bup;
e9ce8d39 A	141	struct stat s;
	142	dev_t root_dev;
	143	ino_t root_ino;
	144	size_t ptsize, upsize;
	145	int save_errno;
9385eb3d	146	char ept, eup, *up, c;
e9ce8d39 A	147
	148	/*
	149	* If no buffer specified by the user, allocate one as necessary.
	150	* If a buffer is specified, the size has to be non-zero. The path
	151	* is built from the end of the buffer backwards.
	152	*/
	153	if (pt) {
	154	ptsize = 0;
	155	if (!size) {
	156	errno = EINVAL;
	157	return (NULL);
	158	}
9385eb3d A	159	if (size == 1) {
	160	errno = ERANGE;
	161	return (NULL);
	162	}
e9ce8d39 A	163	ept = pt + size;
e9ce8d39 A	164	} else {
ad3c9f2a	165	if ((pt = malloc(ptsize = MAXPATHLEN)) == NULL)
e9ce8d39 A	166	return (NULL);
	167	ept = pt + ptsize;
	168	}
ad3c9f2a A	169	if (usegetpath) {
	170	if (__getcwd(pt, ept - pt) == 0) {
	171	return (pt);
	172	} else if (errno == ERANGE) /* failed because buffer too small */
	173	return NULL;
9385eb3d	174	}
e9ce8d39 A	175	bpt = ept - 1;
	176	*bpt = '\0';
	177
	178	/*
ad3c9f2a	179	* Allocate MAXPATHLEN bytes for the string of "../"'s.
1f2f436a	180	* Should always be enough. If it's not, allocate
e9ce8d39 A	181	* as necessary. Special case the first stat, it's ".", not "..".
e9ce8d39 A	182	*/
ad3c9f2a	183	if ((up = malloc(upsize = MAXPATHLEN)) == NULL)
e9ce8d39	184	goto err;
ad3c9f2a	185	eup = up + MAXPATHLEN;
e9ce8d39 A	186	bup = up;
	187	up[0] = '.';
	188	up[1] = '\0';
	189
	190	/* Save root values, so know when to stop. */
	191	if (stat("/", &s))
	192	goto err;
	193	root_dev = s.st_dev;
	194	root_ino = s.st_ino;
	195
	196	errno = 0; /* XXX readdir has no error return. */
	197
	198	for (first = 1;; first = 0) {
	199	/* Stat the current level. */
	200	if (lstat(up, &s))
	201	goto err;
	202
	203	/* Save current node values. */
	204	ino = s.st_ino;
	205	dev = s.st_dev;
	206
	207	/* Check for reaching root. */
	208	if (root_dev == dev && root_ino == ino) {
	209	*--bpt = '/';
	210	/*
	211	* It's unclear that it's a requirement to copy the
	212	* path to the beginning of the buffer, but it's always
	213	* been that way and stuff would probably break.
	214	*/
9385eb3d	215	bcopy(bpt, pt, ept - bpt);
e9ce8d39 A	216	free(up);
	217	return (pt);
	218	}
	219
	220	/*
	221	* Build pointer to the parent directory, allocating memory
	222	* as necessary. Max length is 3 for "../", the largest
9385eb3d	223	* possible component name, plus a trailing NUL.
e9ce8d39	224	*/
1f2f436a	225	while (bup + 3 + MAXNAMLEN + 1 >= eup) {
9385eb3d	226	if ((up = reallocf(up, upsize *= 2)) == NULL)
e9ce8d39 A	227	goto err;
	228	bup = up;
	229	eup = up + upsize;
	230	}
	231	*bup++ = '.';
	232	*bup++ = '.';
	233	*bup = '\0';
	234
	235	/* Open and stat parent directory. */
9385eb3d	236	if (!(dir = opendir(up)) \|\| _fstat(dirfd(dir), &s))
e9ce8d39 A	237	goto err;
	238
	239	/* Add trailing slash for next directory. */
	240	*bup++ = '/';
9385eb3d	241	*bup = '\0';
e9ce8d39 A	242
	243	/*
	244	* If it's a mount point, have to stat each element because
	245	* the inode number in the directory is for the entry in the
	246	* parent directory, not the inode number of the mounted file.
	247	*/
	248	save_errno = 0;
	249	if (s.st_dev == dev) {
	250	for (;;) {
	251	if (!(dp = readdir(dir)))
	252	goto notfound;
	253	if (dp->d_fileno == ino)
	254	break;
	255	}
	256	} else
	257	for (;;) {
	258	if (!(dp = readdir(dir)))
	259	goto notfound;
	260	if (ISDOT(dp))
	261	continue;
	262	bcopy(dp->d_name, bup, dp->d_namlen + 1);
	263
	264	/* Save the first error for later. */
	265	if (lstat(up, &s)) {
	266	if (!save_errno)
	267	save_errno = errno;
	268	errno = 0;
	269	continue;
	270	}
	271	if (s.st_dev == dev && s.st_ino == ino)
	272	break;
	273	}
	274
	275	/*
	276	* Check for length of the current name, preceding slash,
	277	* leading slash.
	278	*/
1f2f436a	279	while (bpt - pt < dp->d_namlen + (first ? 1 : 2)) {
e9ce8d39 A	280	size_t len, off;
	281
	282	if (!ptsize) {
	283	errno = ERANGE;
	284	goto err;
	285	}
	286	off = bpt - pt;
	287	len = ept - bpt;
9385eb3d	288	if ((pt = reallocf(pt, ptsize *= 2)) == NULL)
e9ce8d39 A	289	goto err;
	290	bpt = pt + off;
	291	ept = pt + ptsize;
9385eb3d	292	bcopy(bpt, ept - len, len);
e9ce8d39 A	293	bpt = ept - len;
	294	}
	295	if (!first)
	296	*--bpt = '/';
	297	bpt -= dp->d_namlen;
	298	bcopy(dp->d_name, bpt, dp->d_namlen);
9385eb3d A	299	(void) closedir(dir);
9385eb3d A	300	dir = NULL;
e9ce8d39 A	301
	302	/* Truncate any file name. */
	303	*bup = '\0';
	304	}
	305
	306	notfound:
	307	/*
	308	* If readdir set errno, use it, not any saved error; otherwise,
	309	* didn't find the current directory in its parent directory, set
	310	* errno to ENOENT.
	311	*/
	312	if (!errno)
	313	errno = save_errno ? save_errno : ENOENT;
	314	/* FALLTHROUGH */
	315	err:
9385eb3d A	316	save_errno = errno;
9385eb3d A	317
e9ce8d39 A	318	if (ptsize)
e9ce8d39 A	319	free(pt);
9385eb3d A	320	if (dir)
9385eb3d A	321	(void) closedir(dir);
e9ce8d39	322	free(up);
9385eb3d A	323
9385eb3d A	324	errno = save_errno;
e9ce8d39 A	325	return (NULL);
e9ce8d39 A	326	}
ad3c9f2a A	327
	328	char *
	329	getcwd(pt, size)
	330	char *pt;
	331	size_t size;
	332	{
	333	return __private_getcwd(pt, size, 1);
	334	}