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https://github.com/coreutils/coreutils.git
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222 lines
5.8 KiB
C
222 lines
5.8 KiB
C
/* provide a replacement openat function
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Copyright (C) 2004, 2005 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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/* written by Jim Meyering */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include "openat.h"
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#include <stdlib.h>
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#include <stdarg.h>
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#include <unistd.h>
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#include <errno.h>
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#include <fcntl.h>
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#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
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#include "save-cwd.h"
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#include "gettext.h"
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#define _(msgid) gettext (msgid)
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/* Replacement for Solaris' openat function.
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<http://www.google.com/search?q=openat+site:docs.sun.com>
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Simulate it by doing save_cwd/fchdir/open/restore_cwd.
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If either the save_cwd or the restore_cwd fails (relatively unlikely,
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and usually indicative of a problem that deserves close attention),
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then give a diagnostic and exit nonzero.
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Otherwise, upon failure, set errno and return -1, as openat does.
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Upon successful completion, return a file descriptor. */
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int
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rpl_openat (int fd, char const *file, int flags, ...)
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{
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struct saved_cwd saved_cwd;
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int saved_errno;
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int new_fd;
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mode_t mode = 0;
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if (flags & O_CREAT)
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{
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va_list arg;
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va_start (arg, flags);
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/* Assume that mode_t is passed compatibly with mode_t's type
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after argument promotion. */
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mode = va_arg (arg, mode_t);
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va_end (arg);
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}
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if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file))
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return open (file, flags, mode);
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if (save_cwd (&saved_cwd) != 0)
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openat_save_fail (errno);
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if (fchdir (fd) != 0)
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{
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saved_errno = errno;
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free_cwd (&saved_cwd);
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errno = saved_errno;
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return -1;
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}
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new_fd = open (file, flags, mode);
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saved_errno = errno;
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if (restore_cwd (&saved_cwd) != 0)
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openat_restore_fail (errno);
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free_cwd (&saved_cwd);
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errno = saved_errno;
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return new_fd;
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}
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/* Replacement for Solaris' function by the same name.
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<http://www.google.com/search?q=fdopendir+site:docs.sun.com>
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Simulate it by doing save_cwd/fchdir/opendir(".")/restore_cwd.
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If either the save_cwd or the restore_cwd fails (relatively unlikely,
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and usually indicative of a problem that deserves close attention),
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then give a diagnostic and exit nonzero.
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Otherwise, this function works just like Solaris' fdopendir.
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W A R N I N G:
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Unlike the other fd-related functions here, this one
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effectively consumes its FD parameter. The caller should not
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close or otherwise manipulate FD after calling this function. */
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DIR *
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fdopendir (int fd)
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{
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struct saved_cwd saved_cwd;
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int saved_errno;
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DIR *dir;
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if (fd == AT_FDCWD)
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return opendir (".");
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if (save_cwd (&saved_cwd) != 0)
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openat_save_fail (errno);
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if (fchdir (fd) != 0)
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{
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saved_errno = errno;
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free_cwd (&saved_cwd);
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close (fd);
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errno = saved_errno;
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return NULL;
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}
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dir = opendir (".");
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saved_errno = errno;
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if (restore_cwd (&saved_cwd) != 0)
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openat_restore_fail (errno);
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free_cwd (&saved_cwd);
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close (fd);
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errno = saved_errno;
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return dir;
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}
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/* Replacement for Solaris' function by the same name.
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<http://www.google.com/search?q=fstatat+site:docs.sun.com>
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Simulate it by doing save_cwd/fchdir/(stat|lstat)/restore_cwd.
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If either the save_cwd or the restore_cwd fails (relatively unlikely,
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and usually indicative of a problem that deserves close attention),
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then give a diagnostic and exit nonzero.
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Otherwise, this function works just like Solaris' fstatat. */
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int
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fstatat (int fd, char const *file, struct stat *st, int flag)
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{
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struct saved_cwd saved_cwd;
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int saved_errno;
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int err;
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if (fd == AT_FDCWD)
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return (flag == AT_SYMLINK_NOFOLLOW
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? lstat (file, st)
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: stat (file, st));
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if (save_cwd (&saved_cwd) != 0)
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openat_save_fail (errno);
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if (fchdir (fd) != 0)
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{
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saved_errno = errno;
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free_cwd (&saved_cwd);
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errno = saved_errno;
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return -1;
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}
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err = (flag == AT_SYMLINK_NOFOLLOW
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? lstat (file, st)
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: stat (file, st));
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saved_errno = errno;
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if (restore_cwd (&saved_cwd) != 0)
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openat_restore_fail (errno);
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free_cwd (&saved_cwd);
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errno = saved_errno;
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return err;
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}
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/* Replacement for Solaris' function by the same name.
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<http://www.google.com/search?q=unlinkat+site:docs.sun.com>
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Simulate it by doing save_cwd/fchdir/(unlink|rmdir)/restore_cwd.
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If either the save_cwd or the restore_cwd fails (relatively unlikely,
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and usually indicative of a problem that deserves close attention),
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then give a diagnostic and exit nonzero.
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Otherwise, this function works just like Solaris' unlinkat. */
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int
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unlinkat (int fd, char const *file, int flag)
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{
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struct saved_cwd saved_cwd;
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int saved_errno;
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int err;
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if (fd == AT_FDCWD)
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return (flag == AT_REMOVEDIR ? rmdir (file) : unlink (file));
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if (save_cwd (&saved_cwd) != 0)
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openat_save_fail (errno);
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if (fchdir (fd) != 0)
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{
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saved_errno = errno;
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free_cwd (&saved_cwd);
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errno = saved_errno;
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return -1;
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}
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err = (flag == AT_REMOVEDIR ? rmdir (file) : unlink (file));
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saved_errno = errno;
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if (restore_cwd (&saved_cwd) != 0)
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openat_restore_fail (errno);
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free_cwd (&saved_cwd);
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errno = saved_errno;
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return err;
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}
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