diff options
Diffstat (limited to 'sysdeps/posix/opendir.c')
| -rw-r--r-- | sysdeps/posix/opendir.c | 159 |
1 files changed, 15 insertions, 144 deletions
diff --git a/sysdeps/posix/opendir.c b/sysdeps/posix/opendir.c index 3e09deb805..bb6bd7cc85 100644 --- a/sysdeps/posix/opendir.c +++ b/sysdeps/posix/opendir.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1991-2016 Free Software Foundation, Inc. +/* Copyright (C) 1991-2018 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 @@ -15,24 +15,13 @@ 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 <errno.h> +#include <stdio.h> /* For BUFSIZ. */ +#include <sys/param.h> /* For MIN and MAX. */ -#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 @@ -40,47 +29,9 @@ 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|O_DIRECTORY|O_LARGEFILE|O_CLOEXEC +}; static bool invalid_name (const char *name) @@ -95,33 +46,6 @@ invalid_name (const char *name) 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 int -opendir_oflags (void) -{ - int flags = O_RDONLY|O_NDELAY|EXTRA_FLAGS|O_LARGEFILE; -#ifdef O_CLOEXEC - flags |= O_CLOEXEC; -#endif - return flags; -} - - static DIR * opendir_tail (int fd) { @@ -138,7 +62,7 @@ opendir_tail (int fd) { __set_errno (ENOTDIR); lose: - close_not_cancel_no_status (fd); + __close_nocancel_nostatus (fd); return NULL; } @@ -148,29 +72,12 @@ opendir_tail (int fd) #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 ())); + return opendir_tail (__openat_nocancel (dfd, name, opendir_oflags)); } #endif @@ -182,54 +89,18 @@ __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 ())); + return opendir_tail (__open_nocancel (name, opendir_oflags)); } weak_alias (__opendir, opendir) - -#ifdef __ASSUME_O_CLOEXEC -# define check_have_o_cloexec(fd) 1 -#else -static int -check_have_o_cloexec (int fd) -{ - if (__have_o_cloexec == 0) - __have_o_cloexec = (__fcntl (fd, F_GETFD, 0) & FD_CLOEXEC) == 0 ? -1 : 1; - return __have_o_cloexec > 0; -} -#endif - - DIR * -internal_function __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp) { - /* We always have to set the close-on-exit flag if the user provided - the file descriptor. Otherwise only if we have no working - O_CLOEXEC support. */ -#ifdef O_CLOEXEC - if ((! close_fd && (flags & O_CLOEXEC) == 0) - || ! check_have_o_cloexec (fd)) -#endif - { - if (__builtin_expect (__fcntl (fd, F_SETFD, FD_CLOEXEC), 0) < 0) + /* We have to set the close-on-exit flag if the user provided the + file descriptor. */ + if (!close_fd + && __glibc_unlikely (__fcntl64_nocancel (fd, F_SETFD, FD_CLOEXEC) < 0)) goto lose; - } const size_t default_allocation = (4 * BUFSIZ < sizeof (struct dirent64) ? sizeof (struct dirent64) : 4 * BUFSIZ); @@ -256,7 +127,7 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp) if (close_fd) { int save_errno = errno; - close_not_cancel_no_status (fd); + __close_nocancel_nostatus (fd); __set_errno (save_errno); } return NULL; |