diff options
Diffstat (limited to 'sysdeps/posix/opendir.c')
-rw-r--r-- | sysdeps/posix/opendir.c | 248 |
1 files changed, 0 insertions, 248 deletions
diff --git a/sysdeps/posix/opendir.c b/sysdeps/posix/opendir.c deleted file mode 100644 index 909aa61884..0000000000 --- a/sysdeps/posix/opendir.c +++ /dev/null @@ -1,248 +0,0 @@ -/* Copyright (C) 1991-2017 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 <assert.h> -#include <errno.h> -#include <limits.h> -#include <stdbool.h> -#include <stddef.h> -#include <stdlib.h> -#include <dirent.h> -#include <fcntl.h> -#include <sys/param.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <unistd.h> -#include <stdio.h> -#include <string.h> - -#include <dirstream.h> -#include <not-cancel.h> -#include <kernel-features.h> - -/* The st_blksize value of the directory is used as a hint for the - size of the buffer which receives struct dirent values from the - kernel. st_blksize is limited to MAX_DIR_BUFFER_SIZE, in case the - file system provides a bogus value. */ -#define MAX_DIR_BUFFER_SIZE 1048576U - -/* opendir() must not accidentally open something other than a directory. - Some OS's have kernel support for that, some don't. In the worst - case we have to stat() before the open() AND fstat() after. - - We have to test at runtime for kernel support since libc may have - been compiled with different headers to the kernel it's running on. - This test can't be done reliably in the general case. We'll use - /dev/null, which if it's not a device lots of stuff will break, as - a guinea pig. It may be missing in chroot environments, so we - make sure to fail safe. */ -#ifdef O_DIRECTORY -# ifdef O_DIRECTORY_WORKS -# define o_directory_works 1 -# define tryopen_o_directory() while (1) /* This must not be called. */ -# else -static int o_directory_works; - -static void -tryopen_o_directory (void) -{ - int serrno = errno; - int x = open_not_cancel_2 ("/dev/null", O_RDONLY|O_NDELAY|O_DIRECTORY); - - if (x >= 0) - { - close_not_cancel_no_status (x); - o_directory_works = -1; - } - else if (errno != ENOTDIR) - o_directory_works = -1; - else - o_directory_works = 1; - - __set_errno (serrno); -} -# endif -# define EXTRA_FLAGS O_DIRECTORY -#else -# define EXTRA_FLAGS 0 -#endif - -enum { - opendir_oflags = O_RDONLY|O_NDELAY|EXTRA_FLAGS|O_LARGEFILE|O_CLOEXEC -}; - -static bool -invalid_name (const char *name) -{ - if (__glibc_unlikely (name[0] == '\0')) - { - /* POSIX.1-1990 says an empty name gets ENOENT; - but `open' might like it fine. */ - __set_errno (ENOENT); - return true; - } - return false; -} - - -static bool -need_isdir_precheck (void) -{ -#ifdef O_DIRECTORY - /* Test whether O_DIRECTORY works. */ - if (o_directory_works == 0) - tryopen_o_directory (); - - /* We can skip the expensive `stat' call if O_DIRECTORY works. */ - return o_directory_works < 0; -#endif - return true; -} - -static DIR * -opendir_tail (int fd) -{ - if (__glibc_unlikely (fd < 0)) - return NULL; - - /* Now make sure this really is a directory and nothing changed since the - `stat' call. The S_ISDIR check is superfluous if O_DIRECTORY works, - but it's cheap and we need the stat call for st_blksize anyway. */ - struct stat64 statbuf; - if (__glibc_unlikely (__fxstat64 (_STAT_VER, fd, &statbuf) < 0)) - goto lose; - if (__glibc_unlikely (! S_ISDIR (statbuf.st_mode))) - { - __set_errno (ENOTDIR); - lose: - close_not_cancel_no_status (fd); - return NULL; - } - - return __alloc_dir (fd, true, 0, &statbuf); -} - - -#if IS_IN (libc) -DIR * -internal_function -__opendirat (int dfd, const char *name) -{ - if (__glibc_unlikely (invalid_name (name))) - return NULL; - - if (need_isdir_precheck ()) - { - /* We first have to check whether the name is for a directory. We - cannot do this after the open() call since the open/close operation - performed on, say, a tape device might have undesirable effects. */ - struct stat64 statbuf; - if (__glibc_unlikely (__fxstatat64 (_STAT_VER, dfd, name, - &statbuf, 0) < 0)) - return NULL; - if (__glibc_unlikely (! S_ISDIR (statbuf.st_mode))) - { - __set_errno (ENOTDIR); - return NULL; - } - } - - return opendir_tail (openat_not_cancel_3 (dfd, name, opendir_oflags)); -} -#endif - - -/* Open a directory stream on NAME. */ -DIR * -__opendir (const char *name) -{ - if (__glibc_unlikely (invalid_name (name))) - return NULL; - - if (need_isdir_precheck ()) - { - /* We first have to check whether the name is for a directory. We - cannot do this after the open() call since the open/close operation - performed on, say, a tape device might have undesirable effects. */ - struct stat64 statbuf; - if (__glibc_unlikely (__xstat64 (_STAT_VER, name, &statbuf) < 0)) - return NULL; - if (__glibc_unlikely (! S_ISDIR (statbuf.st_mode))) - { - __set_errno (ENOTDIR); - return NULL; - } - } - - return opendir_tail (open_not_cancel_2 (name, opendir_oflags)); -} -weak_alias (__opendir, opendir) - -DIR * -internal_function -__alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp) -{ - /* We have to set the close-on-exit flag if the user provided the - file descriptor. */ - if (!close_fd - && __builtin_expect (__fcntl (fd, F_SETFD, FD_CLOEXEC), 0) < 0) - goto lose; - - const size_t default_allocation = (4 * BUFSIZ < sizeof (struct dirent64) - ? sizeof (struct dirent64) : 4 * BUFSIZ); - const size_t small_allocation = (BUFSIZ < sizeof (struct dirent64) - ? sizeof (struct dirent64) : BUFSIZ); - size_t allocation = default_allocation; -#ifdef _STATBUF_ST_BLKSIZE - /* Increase allocation if requested, but not if the value appears to - be bogus. */ - if (statp != NULL) - allocation = MIN (MAX ((size_t) statp->st_blksize, default_allocation), - MAX_DIR_BUFFER_SIZE); -#endif - - DIR *dirp = (DIR *) malloc (sizeof (DIR) + allocation); - if (dirp == NULL) - { - allocation = small_allocation; - dirp = (DIR *) malloc (sizeof (DIR) + allocation); - - if (dirp == NULL) - lose: - { - if (close_fd) - { - int save_errno = errno; - close_not_cancel_no_status (fd); - __set_errno (save_errno); - } - return NULL; - } - } - - dirp->fd = fd; -#if IS_IN (libc) - __libc_lock_init (dirp->lock); -#endif - dirp->allocation = allocation; - dirp->size = 0; - dirp->offset = 0; - dirp->filepos = 0; - dirp->errcode = 0; - - return dirp; -} |