[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')))

extern int __getcwd(char *, size_t);

char *
getcwd(pt, size)
	char *pt;
	size_t size;
{
	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 = PATH_MAX)) == NULL)
			return (NULL);
		ept = pt + ptsize;
	}
	if (__getcwd(pt, ept - pt) == 0) {
		if (*pt != '/') {
			bpt = pt;
			ept = pt + strlen(pt) - 1;
			while (bpt < ept) {
				c = *bpt;
				*bpt++ = *ept;
				*ept-- = c;
			}
		}
		return (pt);
	}
	bpt = ept - 1;
	*bpt = '\0';

	/*
	 * Allocate 1024 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 = 1024)) == NULL)
		goto err;
	eup = up + upsize;
	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);
}
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')))
	52
	53	extern int __getcwd(char *, size_t);
e9ce8d39 A	54
	55	char *
	56	getcwd(pt, size)
	57	char *pt;
	58	size_t size;
	59	{
9385eb3d A	60	struct dirent *dp;
9385eb3d A	61	DIR *dir = NULL;
e9ce8d39 A	62	dev_t dev;
e9ce8d39 A	63	ino_t ino;
9385eb3d A	64	int first;
9385eb3d A	65	char bpt, bup;
e9ce8d39 A	66	struct stat s;
	67	dev_t root_dev;
	68	ino_t root_ino;
	69	size_t ptsize, upsize;
	70	int save_errno;
9385eb3d	71	char ept, eup, *up, c;
e9ce8d39 A	72
	73	/*
	74	* If no buffer specified by the user, allocate one as necessary.
	75	* If a buffer is specified, the size has to be non-zero. The path
	76	* is built from the end of the buffer backwards.
	77	*/
	78	if (pt) {
	79	ptsize = 0;
	80	if (!size) {
	81	errno = EINVAL;
	82	return (NULL);
	83	}
9385eb3d A	84	if (size == 1) {
	85	errno = ERANGE;
	86	return (NULL);
	87	}
e9ce8d39 A	88	ept = pt + size;
e9ce8d39 A	89	} else {
1f2f436a	90	if ((pt = malloc(ptsize = PATH_MAX)) == NULL)
e9ce8d39 A	91	return (NULL);
	92	ept = pt + ptsize;
	93	}
9385eb3d A	94	if (__getcwd(pt, ept - pt) == 0) {
	95	if (*pt != '/') {
	96	bpt = pt;
	97	ept = pt + strlen(pt) - 1;
	98	while (bpt < ept) {
	99	c = *bpt;
	100	bpt++ = ept;
	101	*ept-- = c;
	102	}
	103	}
	104	return (pt);
	105	}
e9ce8d39 A	106	bpt = ept - 1;
	107	*bpt = '\0';
	108
	109	/*
1f2f436a A	110	* Allocate 1024 bytes for the string of "../"'s.
1f2f436a A	111	* Should always be enough. If it's not, allocate
e9ce8d39 A	112	* as necessary. Special case the first stat, it's ".", not "..".
e9ce8d39 A	113	*/
1f2f436a	114	if ((up = malloc(upsize = 1024)) == NULL)
e9ce8d39	115	goto err;
1f2f436a	116	eup = up + upsize;
e9ce8d39 A	117	bup = up;
	118	up[0] = '.';
	119	up[1] = '\0';
	120
	121	/* Save root values, so know when to stop. */
	122	if (stat("/", &s))
	123	goto err;
	124	root_dev = s.st_dev;
	125	root_ino = s.st_ino;
	126
	127	errno = 0; /* XXX readdir has no error return. */
	128
	129	for (first = 1;; first = 0) {
	130	/* Stat the current level. */
	131	if (lstat(up, &s))
	132	goto err;
	133
	134	/* Save current node values. */
	135	ino = s.st_ino;
	136	dev = s.st_dev;
	137
	138	/* Check for reaching root. */
	139	if (root_dev == dev && root_ino == ino) {
	140	*--bpt = '/';
	141	/*
	142	* It's unclear that it's a requirement to copy the
	143	* path to the beginning of the buffer, but it's always
	144	* been that way and stuff would probably break.
	145	*/
9385eb3d	146	bcopy(bpt, pt, ept - bpt);
e9ce8d39 A	147	free(up);
	148	return (pt);
	149	}
	150
	151	/*
	152	* Build pointer to the parent directory, allocating memory
	153	* as necessary. Max length is 3 for "../", the largest
9385eb3d	154	* possible component name, plus a trailing NUL.
e9ce8d39	155	*/
1f2f436a	156	while (bup + 3 + MAXNAMLEN + 1 >= eup) {
9385eb3d	157	if ((up = reallocf(up, upsize *= 2)) == NULL)
e9ce8d39 A	158	goto err;
	159	bup = up;
	160	eup = up + upsize;
	161	}
	162	*bup++ = '.';
	163	*bup++ = '.';
	164	*bup = '\0';
	165
	166	/* Open and stat parent directory. */
9385eb3d	167	if (!(dir = opendir(up)) \|\| _fstat(dirfd(dir), &s))
e9ce8d39 A	168	goto err;
	169
	170	/* Add trailing slash for next directory. */
	171	*bup++ = '/';
9385eb3d	172	*bup = '\0';
e9ce8d39 A	173
	174	/*
	175	* If it's a mount point, have to stat each element because
	176	* the inode number in the directory is for the entry in the
	177	* parent directory, not the inode number of the mounted file.
	178	*/
	179	save_errno = 0;
	180	if (s.st_dev == dev) {
	181	for (;;) {
	182	if (!(dp = readdir(dir)))
	183	goto notfound;
	184	if (dp->d_fileno == ino)
	185	break;
	186	}
	187	} else
	188	for (;;) {
	189	if (!(dp = readdir(dir)))
	190	goto notfound;
	191	if (ISDOT(dp))
	192	continue;
	193	bcopy(dp->d_name, bup, dp->d_namlen + 1);
	194
	195	/* Save the first error for later. */
	196	if (lstat(up, &s)) {
	197	if (!save_errno)
	198	save_errno = errno;
	199	errno = 0;
	200	continue;
	201	}
	202	if (s.st_dev == dev && s.st_ino == ino)
	203	break;
	204	}
	205
	206	/*
	207	* Check for length of the current name, preceding slash,
	208	* leading slash.
	209	*/
1f2f436a	210	while (bpt - pt < dp->d_namlen + (first ? 1 : 2)) {
e9ce8d39 A	211	size_t len, off;
	212
	213	if (!ptsize) {
	214	errno = ERANGE;
	215	goto err;
	216	}
	217	off = bpt - pt;
	218	len = ept - bpt;
9385eb3d	219	if ((pt = reallocf(pt, ptsize *= 2)) == NULL)
e9ce8d39 A	220	goto err;
	221	bpt = pt + off;
	222	ept = pt + ptsize;
9385eb3d	223	bcopy(bpt, ept - len, len);
e9ce8d39 A	224	bpt = ept - len;
	225	}
	226	if (!first)
	227	*--bpt = '/';
	228	bpt -= dp->d_namlen;
	229	bcopy(dp->d_name, bpt, dp->d_namlen);
9385eb3d A	230	(void) closedir(dir);
9385eb3d A	231	dir = NULL;
e9ce8d39 A	232
	233	/* Truncate any file name. */
	234	*bup = '\0';
	235	}
	236
	237	notfound:
	238	/*
	239	* If readdir set errno, use it, not any saved error; otherwise,
	240	* didn't find the current directory in its parent directory, set
	241	* errno to ENOENT.
	242	*/
	243	if (!errno)
	244	errno = save_errno ? save_errno : ENOENT;
	245	/* FALLTHROUGH */
	246	err:
9385eb3d A	247	save_errno = errno;
9385eb3d A	248
e9ce8d39 A	249	if (ptsize)
e9ce8d39 A	250	free(pt);
9385eb3d A	251	if (dir)
9385eb3d A	252	(void) closedir(dir);
e9ce8d39	253	free(up);
9385eb3d A	254
9385eb3d A	255	errno = save_errno;
e9ce8d39 A	256	return (NULL);
e9ce8d39 A	257	}