fbbd9655e5
Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96
361 lines
8.4 KiB
C
361 lines
8.4 KiB
C
/*-
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* Copyright (c) 1983, 1993
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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. 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[] = "@(#)opendir.c 8.8 (Berkeley) 5/1/95";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "namespace.h"
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#include <sys/param.h>
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#include <sys/mount.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 <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "un-namespace.h"
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#include "gen-private.h"
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#include "telldir.h"
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static DIR * __opendir_common(int, int, bool);
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/*
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* Open a directory.
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*/
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DIR *
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opendir(const char *name)
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{
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return (__opendir2(name, DTF_HIDEW|DTF_NODUP));
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}
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/*
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* Open a directory with existing file descriptor.
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*/
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DIR *
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fdopendir(int fd)
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{
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if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
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return (NULL);
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return (__opendir_common(fd, DTF_HIDEW|DTF_NODUP, true));
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}
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DIR *
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__opendir2(const char *name, int flags)
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{
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int fd;
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DIR *dir;
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int saved_errno;
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if ((flags & (__DTF_READALL | __DTF_SKIPREAD)) != 0)
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return (NULL);
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if ((fd = _open(name,
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O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC)) == -1)
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return (NULL);
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dir = __opendir_common(fd, flags, false);
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if (dir == NULL) {
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saved_errno = errno;
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_close(fd);
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errno = saved_errno;
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}
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return (dir);
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}
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static int
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opendir_compar(const void *p1, const void *p2)
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{
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return (strcmp((*(const struct dirent **)p1)->d_name,
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(*(const struct dirent **)p2)->d_name));
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}
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/*
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* For a directory at the top of a unionfs stack, the entire directory's
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* contents are read and cached locally until the next call to rewinddir().
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* For the fdopendir() case, the initial seek position must be preserved.
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* For rewinddir(), the full directory should always be re-read from the
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* beginning.
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*
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* If an error occurs, the existing buffer and state of 'dirp' is left
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* unchanged.
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*/
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bool
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_filldir(DIR *dirp, bool use_current_pos)
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{
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struct dirent **dpv;
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char *buf, *ddptr, *ddeptr;
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off_t pos;
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int fd2, incr, len, n, saved_errno, space;
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len = 0;
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space = 0;
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buf = NULL;
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ddptr = NULL;
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/*
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* Use the system page size if that is a multiple of DIRBLKSIZ.
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* Hopefully this can be a big win someday by allowing page
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* trades to user space to be done by _getdirentries().
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*/
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incr = getpagesize();
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if ((incr % DIRBLKSIZ) != 0)
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incr = DIRBLKSIZ;
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/*
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* The strategy here is to read all the directory
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* entries into a buffer, sort the buffer, and
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* remove duplicate entries by setting the inode
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* number to zero.
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*
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* We reopen the directory because _getdirentries()
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* on a MNT_UNION mount modifies the open directory,
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* making it refer to the lower directory after the
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* upper directory's entries are exhausted.
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* This would otherwise break software that uses
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* the directory descriptor for fchdir or *at
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* functions, such as fts.c.
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*/
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if ((fd2 = _openat(dirp->dd_fd, ".", O_RDONLY | O_CLOEXEC)) == -1)
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return (false);
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if (use_current_pos) {
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pos = lseek(dirp->dd_fd, 0, SEEK_CUR);
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if (pos == -1 || lseek(fd2, pos, SEEK_SET) == -1) {
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saved_errno = errno;
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_close(fd2);
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errno = saved_errno;
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return (false);
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}
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}
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do {
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/*
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* Always make at least DIRBLKSIZ bytes
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* available to _getdirentries
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*/
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if (space < DIRBLKSIZ) {
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space += incr;
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len += incr;
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buf = reallocf(buf, len);
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if (buf == NULL) {
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saved_errno = errno;
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_close(fd2);
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errno = saved_errno;
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return (false);
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}
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ddptr = buf + (len - space);
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}
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n = _getdirentries(fd2, ddptr, space, &dirp->dd_seek);
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if (n > 0) {
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ddptr += n;
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space -= n;
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}
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if (n < 0) {
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saved_errno = errno;
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_close(fd2);
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errno = saved_errno;
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return (false);
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}
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} while (n > 0);
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_close(fd2);
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ddeptr = ddptr;
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/*
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* There is now a buffer full of (possibly) duplicate
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* names.
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*/
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dirp->dd_buf = buf;
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/*
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* Go round this loop twice...
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*
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* Scan through the buffer, counting entries.
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* On the second pass, save pointers to each one.
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* Then sort the pointers and remove duplicate names.
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*/
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for (dpv = NULL;;) {
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n = 0;
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ddptr = buf;
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while (ddptr < ddeptr) {
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struct dirent *dp;
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dp = (struct dirent *) ddptr;
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if ((long)dp & 03L)
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break;
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if ((dp->d_reclen <= 0) ||
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(dp->d_reclen > (ddeptr + 1 - ddptr)))
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break;
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ddptr += dp->d_reclen;
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if (dp->d_fileno) {
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if (dpv)
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dpv[n] = dp;
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n++;
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}
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}
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if (dpv) {
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struct dirent *xp;
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/*
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* This sort must be stable.
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*/
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mergesort(dpv, n, sizeof(*dpv), opendir_compar);
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dpv[n] = NULL;
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xp = NULL;
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/*
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* Scan through the buffer in sort order,
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* zapping the inode number of any
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* duplicate names.
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*/
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for (n = 0; dpv[n]; n++) {
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struct dirent *dp = dpv[n];
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if ((xp == NULL) ||
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strcmp(dp->d_name, xp->d_name)) {
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xp = dp;
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} else {
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dp->d_fileno = 0;
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}
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if (dp->d_type == DT_WHT &&
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(dirp->dd_flags & DTF_HIDEW))
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dp->d_fileno = 0;
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}
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free(dpv);
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break;
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} else {
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dpv = malloc((n+1) * sizeof(struct dirent *));
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if (dpv == NULL)
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break;
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}
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}
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dirp->dd_len = len;
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dirp->dd_size = ddptr - dirp->dd_buf;
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return (true);
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}
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/*
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* Common routine for opendir(3), __opendir2(3) and fdopendir(3).
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*/
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static DIR *
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__opendir_common(int fd, int flags, bool use_current_pos)
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{
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DIR *dirp;
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int incr;
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int saved_errno;
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int unionstack;
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if ((dirp = malloc(sizeof(DIR) + sizeof(struct _telldir))) == NULL)
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return (NULL);
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dirp->dd_buf = NULL;
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dirp->dd_fd = fd;
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dirp->dd_flags = flags;
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dirp->dd_loc = 0;
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dirp->dd_lock = NULL;
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dirp->dd_td = (struct _telldir *)((char *)dirp + sizeof(DIR));
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LIST_INIT(&dirp->dd_td->td_locq);
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dirp->dd_td->td_loccnt = 0;
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/*
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* Use the system page size if that is a multiple of DIRBLKSIZ.
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* Hopefully this can be a big win someday by allowing page
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* trades to user space to be done by _getdirentries().
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*/
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incr = getpagesize();
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if ((incr % DIRBLKSIZ) != 0)
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incr = DIRBLKSIZ;
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/*
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* Determine whether this directory is the top of a union stack.
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*/
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if (flags & DTF_NODUP) {
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struct statfs sfb;
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if (_fstatfs(fd, &sfb) < 0)
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goto fail;
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unionstack = !strcmp(sfb.f_fstypename, "unionfs")
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|| (sfb.f_flags & MNT_UNION);
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} else {
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unionstack = 0;
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}
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if (unionstack) {
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if (!_filldir(dirp, use_current_pos))
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goto fail;
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dirp->dd_flags |= __DTF_READALL;
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} else {
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dirp->dd_len = incr;
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dirp->dd_buf = malloc(dirp->dd_len);
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if (dirp->dd_buf == NULL)
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goto fail;
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if (use_current_pos) {
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/*
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* Read the first batch of directory entries
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* to prime dd_seek. This also checks if the
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* fd passed to fdopendir() is a directory.
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*/
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dirp->dd_size = _getdirentries(dirp->dd_fd,
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dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
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if (dirp->dd_size < 0) {
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if (errno == EINVAL)
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errno = ENOTDIR;
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goto fail;
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}
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dirp->dd_flags |= __DTF_SKIPREAD;
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} else {
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dirp->dd_size = 0;
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dirp->dd_seek = 0;
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}
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}
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return (dirp);
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fail:
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saved_errno = errno;
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free(dirp->dd_buf);
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free(dirp);
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errno = saved_errno;
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return (NULL);
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}
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