ossp-pkg/path/path_resolve.c
1.2
/*
** OSSP path - Filesystem Path Manipulation
** Copyright (c) 2002 Ralf S. Engelschall <rse@engelschall.com>
** Copyright (c) 2002 The OSSP Project <http://www.ossp.org/>
** Copyright (c) 2002 Cable & Wireless Deutschland <http://www.cw.com/de/>
**
** This file is part of OSSP path, a filesystem path manipulation library
** which can be found at http://www.ossp.org/pkg/lib/path/.
**
** Permission to use, copy, modify, and distribute this software for
** any purpose with or without fee is hereby granted, provided that
** the above copyright notice and this permission notice appear in all
** copies.
**
** THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 AUTHORS AND COPYRIGHT HOLDERS AND THEIR
** 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.
**
** path_resolve.c: pathname resolving
*/
/*
* Copyright (c) 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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.
*/
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/stat.h>
#include "path.h"
char *
path_resolve(
char *outbuf,
size_t outsize,
const char *path)
{
struct stat sb;
int fd, n, rootd, serrno;
char *p, *q, wbuf[MAXPATHLEN];
char resolved[MAXPATHLEN];
int symlinks = 0;
/* save the starting point */
if ((fd = open(".", O_RDONLY)) < 0) {
strcpy(resolved, ".");
return NULL;
}
/*
* Find the dirname and basename from the path to be resolved.
* Change directory to the dirname component.
* lstat() the basename part.
* if it is a symlink, read in the value and loop.
* if it is a directory, then change to that directory.
* get the current directory name and append the basename.
*/
strncpy(resolved, path, MAXPATHLEN - 1);
resolved[MAXPATHLEN-1] = '\0';
loop:
if ((q = strrchr(resolved, '/')) != NULL) {
p = q + 1;
if (q == resolved)
q = "/";
else {
do {
--q;
} while (q > resolved && *q == '/');
q[1] = '\0';
q = resolved;
}
if (chdir(q) < 0)
goto err1;
} else
p = resolved;
/* Deal with the last component. */
if (*p != '\0' && lstat(p, &sb) == 0) {
if (S_ISLNK(sb.st_mode)) {
if (++symlinks > MAXSYMLINKS) {
errno = ELOOP;
goto err1;
}
n = readlink(p, resolved, MAXPATHLEN - 1);
if (n < 0)
goto err1;
resolved[n] = '\0';
goto loop;
}
if (S_ISDIR(sb.st_mode)) {
if (chdir(p) < 0)
goto err1;
p = "";
}
}
/*
* Save the last component name and get the full pathname of
* the current directory.
*/
strcpy(wbuf, p);
if (getcwd(resolved, MAXPATHLEN) == 0)
goto err1;
/*
* Join the two strings together, ensuring that the right thing
* happens if the last component is empty, or the dirname is root.
*/
if (resolved[0] == '/' && resolved[1] == '\0')
rootd = 1;
else
rootd = 0;
if (*wbuf) {
if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) {
errno = ENAMETOOLONG;
goto err1;
}
if (rootd == 0)
strcat(resolved, "/");
strcat(resolved, wbuf);
}
/* Go back to where we came from. */
if (fchdir(fd) < 0) {
serrno = errno;
goto err2;
}
/* It's okay if the close fails, what's an fd more or less? */
close(fd);
strncpy(outbuf, resolved, outsize);
outbuf[outsize-1] = '\0';
return outbuf;
err1:
serrno = errno;
fchdir(fd);
err2:
close(fd);
errno = serrno;
return NULL;
}
