/* provide a replacement openat function
- Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2004-2014 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* written by Jim Meyering */
+/* If the user's config.h happens to include <fcntl.h>, let it include only
+ the system's <fcntl.h> here, so that orig_openat doesn't recurse to
+ rpl_openat. */
+#define __need_system_fcntl_h
#include <config.h>
+/* Get the original definition of open. It might be defined as a macro. */
+#include <fcntl.h>
+#include <sys/types.h>
+#undef __need_system_fcntl_h
+
+#if HAVE_OPENAT
+static int
+orig_openat (int fd, char const *filename, int flags, mode_t mode)
+{
+ return openat (fd, filename, flags, mode);
+}
+#endif
+
+/* Write "fcntl.h" here, not <fcntl.h>, otherwise OSF/1 5.1 DTK cc eliminates
+ this include because of the preliminary #include <fcntl.h> above. */
+#include "fcntl.h"
+
#include "openat.h"
-#include <stdlib.h>
#include <stdarg.h>
-#include <unistd.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/stat.h>
#include <errno.h>
-#include <fcntl.h>
-#include "error.h"
-#include "exitfail.h"
-#include "save-cwd.h"
+#if HAVE_OPENAT
-#include "gettext.h"
-#define _(msgid) gettext (msgid)
-
-/* Replacement for Solaris' openat function.
- <http://www.google.com/search?q=openat+site:docs.sun.com>
- Simulate it by doing save_cwd/fchdir/open/restore_cwd.
- If either the save_cwd or the restore_cwd fails (relatively unlikely,
- and usually indicative of a problem that deserves close attention),
- then give a diagnostic and exit nonzero.
- Otherwise, upon failure, set errno and return -1, as openat does.
- Upon successful completion, return a file descriptor. */
+/* Like openat, but work around Solaris 9 bugs with trailing slash. */
int
-rpl_openat (int fd, char const *file, int flags, ...)
+rpl_openat (int dfd, char const *filename, int flags, ...)
{
- struct saved_cwd saved_cwd;
- int saved_errno;
- int new_fd;
- mode_t mode = 0;
+ mode_t mode;
+ int fd;
+ mode = 0;
if (flags & O_CREAT)
{
va_list arg;
va_start (arg, flags);
- /* Assume that mode_t is passed compatibly with mode_t's type
- after argument promotion. */
- mode = va_arg (arg, mode_t);
+ /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
+ creates crashing code when 'mode_t' is smaller than 'int'. */
+ mode = va_arg (arg, PROMOTED_MODE_T);
va_end (arg);
}
- if (fd == AT_FDCWD || *file == '/')
- return open (file, flags, mode);
-
- if (save_cwd (&saved_cwd) != 0)
- error (exit_failure, errno,
- _("openat: unable to record current working directory"));
-
- if (fchdir (fd) != 0)
+# if OPEN_TRAILING_SLASH_BUG
+ /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
+ is specified, then fail.
+ Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
+ says that
+ "A pathname that contains at least one non-slash character and that
+ ends with one or more trailing slashes shall be resolved as if a
+ single dot character ( '.' ) were appended to the pathname."
+ and
+ "The special filename dot shall refer to the directory specified by
+ its predecessor."
+ If the named file already exists as a directory, then
+ - if O_CREAT is specified, open() must fail because of the semantics
+ of O_CREAT,
+ - if O_WRONLY or O_RDWR is specified, open() must fail because POSIX
+ <http://www.opengroup.org/susv3/functions/open.html> says that it
+ fails with errno = EISDIR in this case.
+ If the named file does not exist or does not name a directory, then
+ - if O_CREAT is specified, open() must fail since open() cannot create
+ directories,
+ - if O_WRONLY or O_RDWR is specified, open() must fail because the
+ file does not contain a '.' directory. */
+ if (flags & (O_CREAT | O_WRONLY | O_RDWR))
{
- saved_errno = errno;
- free_cwd (&saved_cwd);
- errno = saved_errno;
- return -1;
+ size_t len = strlen (filename);
+ if (len > 0 && filename[len - 1] == '/')
+ {
+ errno = EISDIR;
+ return -1;
+ }
}
+# endif
+
+ fd = orig_openat (dfd, filename, flags, mode);
+
+# if OPEN_TRAILING_SLASH_BUG
+ /* If the filename ends in a slash and fd does not refer to a directory,
+ then fail.
+ Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
+ says that
+ "A pathname that contains at least one non-slash character and that
+ ends with one or more trailing slashes shall be resolved as if a
+ single dot character ( '.' ) were appended to the pathname."
+ and
+ "The special filename dot shall refer to the directory specified by
+ its predecessor."
+ If the named file without the slash is not a directory, open() must fail
+ with ENOTDIR. */
+ if (fd >= 0)
+ {
+ /* We know len is positive, since open did not fail with ENOENT. */
+ size_t len = strlen (filename);
+ if (filename[len - 1] == '/')
+ {
+ struct stat statbuf;
+
+ if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
+ {
+ close (fd);
+ errno = ENOTDIR;
+ return -1;
+ }
+ }
+ }
+# endif
- new_fd = open (file, flags, mode);
- saved_errno = errno;
+ return fd;
+}
- if (restore_cwd (&saved_cwd) != 0)
- error (exit_failure, errno,
- _("openat: unable to restore working directory"));
+#else /* !HAVE_OPENAT */
- free_cwd (&saved_cwd);
+# include "dosname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
+# include "openat-priv.h"
+# include "save-cwd.h"
- errno = saved_errno;
- return new_fd;
-}
-
-/* Replacement for Solaris' function by the same name.
- <http://www.google.com/search?q=fdopendir+site:docs.sun.com>
- Simulate it by doing save_cwd/fchdir/opendir(".")/restore_cwd.
- If either the save_cwd or the restore_cwd fails (relatively unlikely,
- and usually indicative of a problem that deserves close attention),
+/* Replacement for Solaris' openat function.
+ <http://www.google.com/search?q=openat+site:docs.sun.com>
+ First, try to simulate it via open ("/proc/self/fd/FD/FILE").
+ Failing that, simulate it by doing save_cwd/fchdir/open/restore_cwd.
+ If either the save_cwd or the restore_cwd fails (relatively unlikely),
then give a diagnostic and exit nonzero.
- Otherwise, this function works just like Solaris' fdopendir. */
-DIR *
-fdopendir (int fd)
+ Otherwise, upon failure, set errno and return -1, as openat does.
+ Upon successful completion, return a file descriptor. */
+int
+openat (int fd, char const *file, int flags, ...)
{
- struct saved_cwd saved_cwd;
- int saved_errno;
- DIR *dir;
+ mode_t mode = 0;
- if (fd == AT_FDCWD)
- return opendir (".");
+ if (flags & O_CREAT)
+ {
+ va_list arg;
+ va_start (arg, flags);
- if (save_cwd (&saved_cwd) != 0)
- error (exit_failure, errno,
- _("fdopendir: unable to record current working directory"));
+ /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
+ creates crashing code when 'mode_t' is smaller than 'int'. */
+ mode = va_arg (arg, PROMOTED_MODE_T);
- if (fchdir (fd) != 0)
- {
- saved_errno = errno;
- free_cwd (&saved_cwd);
- errno = saved_errno;
- return NULL;
+ va_end (arg);
}
- dir = opendir (".");
- saved_errno = errno;
+ return openat_permissive (fd, file, flags, mode, NULL);
+}
- if (restore_cwd (&saved_cwd) != 0)
- error (exit_failure, errno,
- _("fdopendir: unable to restore working directory"));
+/* Like openat (FD, FILE, FLAGS, MODE), but if CWD_ERRNO is
+ nonnull, set *CWD_ERRNO to an errno value if unable to save
+ or restore the initial working directory. This is needed only
+ the first time remove.c's remove_dir opens a command-line
+ directory argument.
- free_cwd (&saved_cwd);
+ If a previous attempt to restore the current working directory
+ failed, then we must not even try to access a '.'-relative name.
+ It is the caller's responsibility not to call this function
+ in that case. */
- errno = saved_errno;
- return dir;
-}
-
-/* Replacement for Solaris' function by the same name.
- <http://www.google.com/search?q=fstatat+site:docs.sun.com>
- Simulate it by doing save_cwd/fchdir/(stat|lstat)/restore_cwd.
- If either the save_cwd or the restore_cwd fails (relatively unlikely,
- and usually indicative of a problem that deserves close attention),
- then give a diagnostic and exit nonzero.
- Otherwise, this function works just like Solaris' fstatat. */
int
-fstatat (int fd, char const *file, struct stat *st, int flag)
+openat_permissive (int fd, char const *file, int flags, mode_t mode,
+ int *cwd_errno)
{
struct saved_cwd saved_cwd;
int saved_errno;
int err;
+ bool save_ok;
- if (fd == AT_FDCWD)
- return (flag == AT_SYMLINK_NOFOLLOW
- ? lstat (file, st)
- : stat (file, st));
-
- if (save_cwd (&saved_cwd) != 0)
- error (exit_failure, errno,
- _("fstatat: unable to record current working directory"));
+ if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file))
+ return open (file, flags, mode);
- if (fchdir (fd) != 0)
+ {
+ char buf[OPENAT_BUFFER_SIZE];
+ char *proc_file = openat_proc_name (buf, fd, file);
+ if (proc_file)
+ {
+ int open_result = open (proc_file, flags, mode);
+ int open_errno = errno;
+ if (proc_file != buf)
+ free (proc_file);
+ /* If the syscall succeeds, or if it fails with an unexpected
+ errno value, then return right away. Otherwise, fall through
+ and resort to using save_cwd/restore_cwd. */
+ if (0 <= open_result || ! EXPECTED_ERRNO (open_errno))
+ {
+ errno = open_errno;
+ return open_result;
+ }
+ }
+ }
+
+ save_ok = (save_cwd (&saved_cwd) == 0);
+ if (! save_ok)
{
- saved_errno = errno;
+ if (! cwd_errno)
+ openat_save_fail (errno);
+ *cwd_errno = errno;
+ }
+ if (0 <= fd && fd == saved_cwd.desc)
+ {
+ /* If saving the working directory collides with the user's
+ requested fd, then the user's fd must have been closed to
+ begin with. */
free_cwd (&saved_cwd);
- errno = saved_errno;
+ errno = EBADF;
return -1;
}
- err = (flag == AT_SYMLINK_NOFOLLOW
- ? lstat (file, st)
- : stat (file, st));
+ err = fchdir (fd);
saved_errno = errno;
- if (restore_cwd (&saved_cwd) != 0)
- error (exit_failure, errno,
- _("fstatat: unable to restore working directory"));
+ if (! err)
+ {
+ err = open (file, flags, mode);
+ saved_errno = errno;
+ if (save_ok && restore_cwd (&saved_cwd) != 0)
+ {
+ if (! cwd_errno)
+ {
+ /* Don't write a message to just-created fd 2. */
+ saved_errno = errno;
+ if (err == STDERR_FILENO)
+ close (err);
+ openat_restore_fail (saved_errno);
+ }
+ *cwd_errno = errno;
+ }
+ }
free_cwd (&saved_cwd);
-
errno = saved_errno;
return err;
}
+
+/* Return true if our openat implementation must resort to
+ using save_cwd and restore_cwd. */
+bool
+openat_needs_fchdir (void)
+{
+ bool needs_fchdir = true;
+ int fd = open ("/", O_SEARCH);
+
+ if (0 <= fd)
+ {
+ char buf[OPENAT_BUFFER_SIZE];
+ char *proc_file = openat_proc_name (buf, fd, ".");
+ if (proc_file)
+ {
+ needs_fchdir = false;
+ if (proc_file != buf)
+ free (proc_file);
+ }
+ close (fd);
+ }
+
+ return needs_fchdir;
+}
+
+#endif /* !HAVE_OPENAT */
projects / gnulib.git / blobdiff