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-rw-r--r--gnu/openat.c267
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diff --git a/gnu/openat.c b/gnu/openat.c
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-/* -*- buffer-read-only: t -*- vi: set ro: */
-/* DO NOT EDIT! GENERATED AUTOMATICALLY! */
-/* provide a replacement openat function
- Copyright (C) 2004-2010 Free Software Foundation, Inc.
-
- 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 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
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- 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, see <http://www.gnu.org/licenses/>. */
-
-/* written by Jim Meyering */
-
-#include <config.h>
-
-#include "openat.h"
-
-#include <stdarg.h>
-#include <stddef.h>
-#include <string.h>
-#include <sys/stat.h>
-
-#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
-#include "openat-priv.h"
-#include "save-cwd.h"
-
-#if HAVE_OPENAT
-
-# undef openat
-
-/* Like openat, but work around Solaris 9 bugs with trailing slash. */
-int
-rpl_openat (int dfd, char const *filename, int flags, ...)
-{
- mode_t mode;
- int fd;
-
- mode = 0;
- if (flags & O_CREAT)
- {
- va_list arg;
- va_start (arg, flags);
-
- /* 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 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))
- {
- size_t len = strlen (filename);
- if (len > 0 && filename[len - 1] == '/')
- {
- errno = EISDIR;
- return -1;
- }
- }
-#endif
-
- fd = 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
-
- return fd;
-}
-
-#else /* !HAVE_OPENAT */
-
-/* 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, 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, ...)
-{
- mode_t mode = 0;
-
- if (flags & O_CREAT)
- {
- va_list arg;
- va_start (arg, flags);
-
- /* 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);
- }
-
- return openat_permissive (fd, file, flags, mode, NULL);
-}
-
-/* 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.
-
- 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. */
-
-int
-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 || IS_ABSOLUTE_FILE_NAME (file))
- return open (file, flags, mode);
-
- {
- 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)
- {
- 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 = EBADF;
- return -1;
- }
-
- err = fchdir (fd);
- saved_errno = errno;
-
- 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_RDONLY);
-
- 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 */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-25 04:33:53 +0000