[openssh.git] / openbsd-compat / getcwd.c

/*	$OpenBSD: getcwd.c,v 1.14 2005/08/08 08:05:34 espie Exp $ */
/*
 * Copyright (c) 1989, 1991, 1993
 *	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.
 * 3. 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.
 */

/* OPENBSD ORIGINAL: lib/libc/gen/getcwd.c */

#include "includes.h"

#if !defined(HAVE_GETCWD)

#include <sys/param.h>
#include <sys/stat.h>
#include <errno.h>
#include <dirent.h>
#include <sys/dir.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "includes.h"

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

char *
getcwd(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;

	/*
	 * 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);
		}
		ept = pt + size;
	} else {
		if ((pt = malloc(ptsize = MAXPATHLEN)) == NULL)
			return (NULL);
		ept = pt + ptsize;
	}
	bpt = ept - 1;
	*bpt = '\0';

	/*
	 * Allocate bytes for the string of "../"'s.
	 * Should always be enough (it's 340 levels).  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 + 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.
			 */
			memmove(pt, bpt, 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.
		 */
		if (bup + 3  + MAXNAMLEN + 1 >= eup) {
			char *nup;

			if ((nup = realloc(up, upsize *= 2)) == NULL)
				goto err;
			bup = nup + (bup - up);
			up = nup;
			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++ = '/';

		/*
		 * 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;
				memcpy(bup, dp->d_name, 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.
		 */
		if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) {
			size_t len;
			char *npt;

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

		/* 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);
	free(up);
	if (dir)
		(void)closedir(dir);

	errno = save_errno;

	return (NULL);
}

#endif /* !defined(HAVE_GETCWD) */
Commit	Line	Data
281bbb02	1	/* $OpenBSD: getcwd.c,v 1.14 2005/08/08 08:05:34 espie Exp $ */
443172c4	2	/*
	3	* Copyright (c) 1989, 1991, 1993
	4	* The Regents of the University of California. All rights reserved.
	5	*
	6	* Redistribution and use in source and binary forms, with or without
	7	* modification, are permitted provided that the following conditions
	8	* are met:
	9	* 1. Redistributions of source code must retain the above copyright
	10	* notice, this list of conditions and the following disclaimer.
	11	* 2. Redistributions in binary form must reproduce the above copyright
	12	* notice, this list of conditions and the following disclaimer in the
	13	* documentation and/or other materials provided with the distribution.
3e67f7df	14	* 3. Neither the name of the University nor the names of its contributors
	15	* may be used to endorse or promote products derived from this software
	16	* without specific prior written permission.
443172c4	17	*
	18	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	19	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	20	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	21	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	22	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	23	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	24	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	25	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	26	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	27	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	28	* SUCH DAMAGE.
	29	*/
	30
f6d4fb87	31	/* OPENBSD ORIGINAL: lib/libc/gen/getcwd.c */
f6d4fb87	32
17962c40	33	#include "includes.h"
443172c4	34
	35	#if !defined(HAVE_GETCWD)
	36
443172c4	37	#include <sys/param.h>
	38	#include <sys/stat.h>
	39	#include <errno.h>
	40	#include <dirent.h>
	41	#include <sys/dir.h>
	42	#include <stdio.h>
	43	#include <stdlib.h>
	44	#include <string.h>
	45	#include "includes.h"
	46
	47	#define ISDOT(dp) \
	48	(dp->d_name[0] == '.' && (dp->d_name[1] == '\0' \|\| \
	49	(dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
	50
	51	char *
510a42ce	52	getcwd(char *pt, size_t size)
443172c4	53	{
281bbb02	54	struct dirent *dp;
	55	DIR *dir = NULL;
	56	dev_t dev;
	57	ino_t ino;
	58	int first;
	59	char bpt, bup;
443172c4	60	struct stat s;
	61	dev_t root_dev;
	62	ino_t root_ino;
	63	size_t ptsize, upsize;
	64	int save_errno;
	65	char ept, eup, *up;
	66
	67	/*
	68	* If no buffer specified by the user, allocate one as necessary.
	69	* If a buffer is specified, the size has to be non-zero. The path
	70	* is built from the end of the buffer backwards.
	71	*/
	72	if (pt) {
	73	ptsize = 0;
	74	if (!size) {
	75	errno = EINVAL;
	76	return (NULL);
	77	}
	78	ept = pt + size;
	79	} else {
281bbb02	80	if ((pt = malloc(ptsize = MAXPATHLEN)) == NULL)
443172c4	81	return (NULL);
	82	ept = pt + ptsize;
	83	}
	84	bpt = ept - 1;
	85	*bpt = '\0';
	86
	87	/*
281bbb02	88	* Allocate bytes for the string of "../"'s.
443172c4	89	* Should always be enough (it's 340 levels). If it's not, allocate
	90	* as necessary. Special * case the first stat, it's ".", not "..".
	91	*/
281bbb02	92	if ((up = malloc(upsize = MAXPATHLEN)) == NULL)
443172c4	93	goto err;
281bbb02	94	eup = up + upsize;
443172c4	95	bup = up;
	96	up[0] = '.';
	97	up[1] = '\0';
	98
	99	/* Save root values, so know when to stop. */
	100	if (stat("/", &s))
	101	goto err;
	102	root_dev = s.st_dev;
	103	root_ino = s.st_ino;
	104
	105	errno = 0; /* XXX readdir has no error return. */
	106
	107	for (first = 1;; first = 0) {
	108	/* Stat the current level. */
	109	if (lstat(up, &s))
	110	goto err;
	111
	112	/* Save current node values. */
	113	ino = s.st_ino;
	114	dev = s.st_dev;
	115
	116	/* Check for reaching root. */
	117	if (root_dev == dev && root_ino == ino) {
	118	*--bpt = '/';
	119	/*
	120	* It's unclear that it's a requirement to copy the
	121	* path to the beginning of the buffer, but it's always
	122	* been that way and stuff would probably break.
	123	*/
8b3319f4	124	memmove(pt, bpt, ept - bpt);
443172c4	125	free(up);
	126	return (pt);
	127	}
	128
	129	/*
	130	* Build pointer to the parent directory, allocating memory
	131	* as necessary. Max length is 3 for "../", the largest
7bb526ce	132	* possible component name, plus a trailing NUL.
443172c4	133	*/
	134	if (bup + 3 + MAXNAMLEN + 1 >= eup) {
	135	char *nup;
	136
	137	if ((nup = realloc(up, upsize *= 2)) == NULL)
	138	goto err;
281bbb02	139	bup = nup + (bup - up);
443172c4	140	up = nup;
443172c4	141	eup = up + upsize;
	142	}
	143	*bup++ = '.';
	144	*bup++ = '.';
	145	*bup = '\0';
	146
16d51c41	147	/* Open and stat parent directory. */
16d51c41	148	if (!(dir = opendir(up)) \|\| fstat(dirfd(dir), &s))
443172c4	149	goto err;
	150
	151	/* Add trailing slash for next directory. */
	152	*bup++ = '/';
	153
	154	/*
	155	* If it's a mount point, have to stat each element because
	156	* the inode number in the directory is for the entry in the
	157	* parent directory, not the inode number of the mounted file.
	158	*/
	159	save_errno = 0;
	160	if (s.st_dev == dev) {
	161	for (;;) {
	162	if (!(dp = readdir(dir)))
	163	goto notfound;
	164	if (dp->d_fileno == ino)
	165	break;
	166	}
	167	} else
	168	for (;;) {
	169	if (!(dp = readdir(dir)))
	170	goto notfound;
	171	if (ISDOT(dp))
	172	continue;
281bbb02	173	memcpy(bup, dp->d_name, dp->d_namlen + 1);
443172c4	174
	175	/* Save the first error for later. */
	176	if (lstat(up, &s)) {
	177	if (!save_errno)
	178	save_errno = errno;
	179	errno = 0;
	180	continue;
	181	}
	182	if (s.st_dev == dev && s.st_ino == ino)
	183	break;
	184	}
	185
	186	/*
	187	* Check for length of the current name, preceding slash,
	188	* leading slash.
	189	*/
	190	if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) {
281bbb02	191	size_t len;
443172c4	192	char *npt;
	193
	194	if (!ptsize) {
	195	errno = ERANGE;
	196	goto err;
	197	}
443172c4	198	len = ept - bpt;
	199	if ((npt = realloc(pt, ptsize *= 2)) == NULL)
	200	goto err;
281bbb02	201	bpt = npt + (bpt - pt);
443172c4	202	pt = npt;
443172c4	203	ept = pt + ptsize;
8b3319f4	204	memmove(ept - len, bpt, len);
443172c4	205	bpt = ept - len;
	206	}
	207	if (!first)
	208	*--bpt = '/';
	209	bpt -= dp->d_namlen;
281bbb02	210	memcpy(bpt, dp->d_name, dp->d_namlen);
443172c4	211	(void)closedir(dir);
	212
	213	/* Truncate any file name. */
	214	*bup = '\0';
	215	}
	216
	217	notfound:
	218	/*
	219	* If readdir set errno, use it, not any saved error; otherwise,
	220	* didn't find the current directory in its parent directory, set
	221	* errno to ENOENT.
	222	*/
	223	if (!errno)
	224	errno = save_errno ? save_errno : ENOENT;
	225	/* FALLTHROUGH */
	226	err:
281bbb02	227	save_errno = errno;
281bbb02	228
443172c4	229	if (ptsize)
443172c4	230	free(pt);
281bbb02	231	free(up);
443172c4	232	if (dir)
443172c4	233	(void)closedir(dir);
281bbb02	234
	235	errno = save_errno;
	236
443172c4	237	return (NULL);
	238	}
	239
	240	#endif /* !defined(HAVE_GETCWD) */