/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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.
* 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 <sys/cdefs.h>
__SCCSID("@(#)getcwd.c 8.5 (Berkeley) 2/7/95");
#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"
#include "gen-private.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(char *pt, size_t size)
{
struct dirent *dp;
DIR *dir = NULL;
dev_t dev;
ino_t ino;
int first;
char *bpt;
struct stat s;
dev_t root_dev;
ino_t root_ino;
size_t ptsize;
int save_errno;
char *ept, c;
int fd;
/*
* 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';
/* 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 (dir != NULL ? _fstat(_dirfd(dir), &s) : lstat(".", &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);
if (dir)
(void) closedir(dir);
return (pt);
}
/* Open and stat parent directory. */
fd = _openat(dir != NULL ? _dirfd(dir) : AT_FDCWD,
"..", O_RDONLY | O_CLOEXEC);
if (fd == -1)
goto err;
if (dir)
(void) closedir(dir);
if (!(dir = fdopendir(fd)) || _fstat(_dirfd(dir), &s)) {
_close(fd);
goto err;
}
/*
* 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;
/* Save the first error for later. */
if (fstatat(_dirfd(dir), dp->d_name, &s,
AT_SYMLINK_NOFOLLOW)) {
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);
}
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);
errno = save_errno;
return (NULL);
}
