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db753e2cfb
Alignment issue can increase the reclen limit. Make sure Linux 64-bit readdir_r also accounts for 64-bit alignment in getdents.
139 lines
3.6 KiB
C
139 lines
3.6 KiB
C
/* Copyright (C) 1991,92,93,94,95,96,97,98,99,2000,02,10
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Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <errno.h>
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#include <limits.h>
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#include <stddef.h>
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#include <string.h>
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#include <dirent.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <assert.h>
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#include <dirstream.h>
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#ifndef __READDIR_R
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# define __READDIR_R __readdir_r
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# define __GETDENTS __getdents
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# define DIRENT_TYPE struct dirent
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# define __READDIR_R_ALIAS
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#endif
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/* Read a directory entry from DIRP. */
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int
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__READDIR_R (DIR *dirp, DIRENT_TYPE *entry, DIRENT_TYPE **result)
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{
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DIRENT_TYPE *dp;
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size_t reclen;
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const int saved_errno = errno;
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__libc_lock_lock (dirp->lock);
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do
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{
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if (dirp->offset >= dirp->size)
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{
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/* We've emptied out our buffer. Refill it. */
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size_t maxread;
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ssize_t bytes;
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#ifndef _DIRENT_HAVE_D_RECLEN
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/* Fixed-size struct; must read one at a time (see below). */
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maxread = sizeof *dp;
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#else
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maxread = dirp->allocation;
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#endif
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bytes = __GETDENTS (dirp->fd, dirp->data, maxread);
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if (bytes <= 0)
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{
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/* On some systems getdents fails with ENOENT when the
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open directory has been rmdir'd already. POSIX.1
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requires that we treat this condition like normal EOF. */
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if (bytes < 0 && errno == ENOENT)
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{
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bytes = 0;
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__set_errno (saved_errno);
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}
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dp = NULL;
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/* Reclen != 0 signals that an error occurred. */
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reclen = bytes != 0;
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break;
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}
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dirp->size = (size_t) bytes;
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/* Reset the offset into the buffer. */
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dirp->offset = 0;
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}
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dp = (DIRENT_TYPE *) &dirp->data[dirp->offset];
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#ifdef _DIRENT_HAVE_D_RECLEN
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reclen = dp->d_reclen;
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#else
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/* The only version of `struct dirent*' that lacks `d_reclen'
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is fixed-size. */
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assert (sizeof dp->d_name > 1);
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reclen = sizeof *dp;
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/* The name is not terminated if it is the largest possible size.
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Clobber the following byte to ensure proper null termination. We
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read just one entry at a time above so we know that byte will not
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be used later. */
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dp->d_name[sizeof dp->d_name] = '\0';
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#endif
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dirp->offset += reclen;
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#ifdef _DIRENT_HAVE_D_OFF
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dirp->filepos = dp->d_off;
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#else
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dirp->filepos += reclen;
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#endif
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/* Skip deleted files. */
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}
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while (dp->d_ino == 0);
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if (dp != NULL)
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{
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#ifdef GETDENTS_64BIT_ALIGNED
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/* The d_reclen value might include padding which is not part of
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the DIRENT_TYPE data structure. */
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reclen = MIN (reclen,
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offsetof (DIRENT_TYPE, d_name) + sizeof (dp->d_name));
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#endif
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*result = memcpy (entry, dp, reclen);
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#ifdef GETDENTS_64BIT_ALIGNED
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entry->d_reclen = reclen;
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#endif
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}
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else
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*result = NULL;
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__libc_lock_unlock (dirp->lock);
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return dp != NULL ? 0 : reclen ? errno : 0;
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}
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#ifdef __READDIR_R_ALIAS
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weak_alias (__readdir_r, readdir_r)
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#endif
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