4773010d2f
overwrites it. This actually showed up when running under an old kernel when free() called the madvise() stub which set errno, causing getcwd() to return EOPNOTSUPP instead of ERANGE.
282 lines
7.1 KiB
C
282 lines
7.1 KiB
C
/*
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* Copyright (c) 1989, 1991, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <dirent.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <signal.h>
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#define ISDOT(dp) \
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(dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
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(dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
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static int have__getcwd = 1; /* 0 = no, 1 = perhaps, 2 = yes */
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char *
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getcwd(pt, size)
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char *pt;
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size_t size;
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{
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register struct dirent *dp;
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register DIR *dir = NULL;
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register dev_t dev;
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register ino_t ino;
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register int first;
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register char *bpt, *bup;
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struct stat s;
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dev_t root_dev;
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ino_t root_ino;
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size_t ptsize, upsize;
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int save_errno;
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char *ept, *eup, *up, c;
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/*
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* If no buffer specified by the user, allocate one as necessary.
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* If a buffer is specified, the size has to be non-zero. The path
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* is built from the end of the buffer backwards.
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*/
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if (pt) {
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ptsize = 0;
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if (!size) {
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errno = EINVAL;
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return (NULL);
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}
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if (size == 1) {
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errno = ERANGE;
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return (NULL);
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}
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ept = pt + size;
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} else {
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if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
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return (NULL);
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ept = pt + ptsize;
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}
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if (have__getcwd) {
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struct sigaction sa, osa;
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int sigsys_installed = 0;
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int ret;
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if (have__getcwd == 1) { /* unsure? */
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bzero(&sa, sizeof(sa));
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sa.sa_handler = SIG_IGN;
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if (sigaction(SIGSYS, &sa, &osa) >= 0)
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sigsys_installed = 1;
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}
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ret = __getcwd(pt, ept - pt);
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if (sigsys_installed == 1) {
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int oerrno = errno;
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sigaction(SIGSYS, &osa, NULL);
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errno = oerrno;
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}
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/* XXX a bogus syscall seems to return EINVAL(!) */
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if (ret < 0 && (errno == ENOSYS || errno == EINVAL))
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have__getcwd = 0;
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else if (have__getcwd == 1)
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have__getcwd = 2; /* yep, remember we have it */
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if (ret == 0) {
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if (*pt != '/') {
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bpt = pt;
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ept = pt + strlen(pt) - 1;
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while (bpt < ept) {
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c = *bpt;
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*bpt++ = *ept;
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*ept-- = c;
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}
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}
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return (pt);
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}
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}
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bpt = ept - 1;
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*bpt = '\0';
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/*
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* Allocate bytes (1024 - malloc space) for the string of "../"'s.
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* Should always be enough (it's 340 levels). If it's not, allocate
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* as necessary. Special case the first stat, it's ".", not "..".
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*/
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if ((up = malloc(upsize = 1024 - 4)) == NULL)
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goto err;
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eup = up + MAXPATHLEN;
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bup = up;
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up[0] = '.';
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up[1] = '\0';
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/* Save root values, so know when to stop. */
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if (stat("/", &s))
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goto err;
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root_dev = s.st_dev;
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root_ino = s.st_ino;
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errno = 0; /* XXX readdir has no error return. */
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for (first = 1;; first = 0) {
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/* Stat the current level. */
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if (lstat(up, &s))
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goto err;
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/* Save current node values. */
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ino = s.st_ino;
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dev = s.st_dev;
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/* Check for reaching root. */
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if (root_dev == dev && root_ino == ino) {
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*--bpt = '/';
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/*
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* It's unclear that it's a requirement to copy the
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* path to the beginning of the buffer, but it's always
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* been that way and stuff would probably break.
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*/
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bcopy(bpt, pt, ept - bpt);
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free(up);
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return (pt);
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}
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/*
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* Build pointer to the parent directory, allocating memory
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* as necessary. Max length is 3 for "../", the largest
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* possible component name, plus a trailing NULL.
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*/
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if (bup + 3 + MAXNAMLEN + 1 >= eup) {
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if ((up = realloc(up, upsize *= 2)) == NULL)
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goto err;
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bup = up;
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eup = up + upsize;
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}
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*bup++ = '.';
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*bup++ = '.';
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*bup = '\0';
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/* Open and stat parent directory. */
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if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
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goto err;
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/* Add trailing slash for next directory. */
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*bup++ = '/';
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*bup = '\0';
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/*
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* If it's a mount point, have to stat each element because
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* the inode number in the directory is for the entry in the
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* parent directory, not the inode number of the mounted file.
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*/
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save_errno = 0;
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if (s.st_dev == dev) {
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for (;;) {
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if (!(dp = readdir(dir)))
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goto notfound;
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if (dp->d_fileno == ino)
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break;
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}
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} else
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for (;;) {
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if (!(dp = readdir(dir)))
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goto notfound;
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if (ISDOT(dp))
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continue;
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bcopy(dp->d_name, bup, dp->d_namlen + 1);
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/* Save the first error for later. */
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if (lstat(up, &s)) {
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if (!save_errno)
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save_errno = errno;
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errno = 0;
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continue;
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}
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if (s.st_dev == dev && s.st_ino == ino)
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break;
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}
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/*
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* Check for length of the current name, preceding slash,
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* leading slash.
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*/
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if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) {
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size_t len, off;
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if (!ptsize) {
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errno = ERANGE;
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goto err;
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}
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off = bpt - pt;
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len = ept - bpt;
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if ((pt = realloc(pt, ptsize *= 2)) == NULL)
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goto err;
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bpt = pt + off;
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ept = pt + ptsize;
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bcopy(bpt, ept - len, len);
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bpt = ept - len;
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}
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if (!first)
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*--bpt = '/';
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bpt -= dp->d_namlen;
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bcopy(dp->d_name, bpt, dp->d_namlen);
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(void) closedir(dir);
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dir = NULL;
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/* Truncate any file name. */
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*bup = '\0';
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}
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notfound:
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/*
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* If readdir set errno, use it, not any saved error; otherwise,
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* didn't find the current directory in its parent directory, set
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* errno to ENOENT.
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*/
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if (!errno)
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errno = save_errno ? save_errno : ENOENT;
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/* FALLTHROUGH */
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err:
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save_errno = errno;
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if (ptsize)
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free(pt);
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if (dir)
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(void) closedir(dir);
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free(up);
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errno = save_errno;
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return (NULL);
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}
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