openbsd-compat/getcwd.c - security/openssh-library - Rivoreo Source Code Repositories

 /*
  * 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.
  */

 #include "includes.h"

 #if !defined(HAVE_GETCWD)

 #if defined(LIBC_SCCS) && !defined(lint)
 static char rcsid[] = "$OpenBSD: getcwd.c,v 1.9 2003/06/11 21:03:10 deraadt Exp $";
 #endif /* LIBC_SCCS and not lint */

 #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)
 {
 	register struct dirent *dp;
 	register DIR *dir = NULL;
 	register dev_t dev;
 	register ino_t ino;
 	register int first;
 	register 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 = 1024 - 4)) == NULL)
 			return (NULL);
 		ept = pt + ptsize;
 	}
 	bpt = ept - 1;
 	*bpt = '\0';

 	/*
 	 * Allocate bytes (1024 - malloc space) 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 = 1024 - 4)) == 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.
 			 */
 			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;
 			up = nup;
 			bup = up;
 			eup = up + upsize;
 		}
 		*bup++ = '.';
 		*bup++ = '.';
 		*bup = '\0';

 		/* Open and stat parent directory.
 		 * RACE?? - replaced fstat(dirfd(dir), &s) w/ lstat(up,&s)
                  */
 		if (!(dir = opendir(up)) || lstat(up,&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;
 				memmove(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, off;
 			char *npt;

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

 #endif /* !defined(HAVE_GETCWD) */
	/*
	* 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.
	*/

	#include "includes.h"

	#if !defined(HAVE_GETCWD)

	#if defined(LIBC_SCCS) && !defined(lint)
	static char rcsid[] = "$OpenBSD: getcwd.c,v 1.9 2003/06/11 21:03:10 deraadt Exp $";
	#endif /* LIBC_SCCS and not lint */

	#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)
	{
	register struct dirent *dp;
	register DIR *dir = NULL;
	register dev_t dev;
	register ino_t ino;
	register int first;
	register 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 = 1024 - 4)) == NULL)
	return (NULL);
	ept = pt + ptsize;
	}
	bpt = ept - 1;
	*bpt = '\0';

	/*
	* Allocate bytes (1024 - malloc space) 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 = 1024 - 4)) == 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.
	*/
	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;
	up = nup;
	bup = up;
	eup = up + upsize;
	}
	*bup++ = '.';
	*bup++ = '.';
	*bup = '\0';

	/* Open and stat parent directory.
	* RACE?? - replaced fstat(dirfd(dir), &s) w/ lstat(up,&s)
	*/
	if (!(dir = opendir(up)) \|\| lstat(up,&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;
	memmove(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, off;
	char *npt;

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

	#endif /* !defined(HAVE_GETCWD) */