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