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105 lines
2.9 KiB
C
105 lines
2.9 KiB
C
/* Change the protections of file relative to an open directory.
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Copyright (C) 2006 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 <errno.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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#include "openat-priv.h"
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/* Some systems don't have ENOSYS. */
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#ifndef ENOSYS
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# ifdef ENOTSUP
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# define ENOSYS ENOTSUP
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# else
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/* Some systems don't have ENOTSUP either. */
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# define ENOSYS EINVAL
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# endif
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#endif
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#ifndef HAVE_LCHMOD
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# undef lchmod
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# define lchmod(f,m) (errno = ENOSYS, -1)
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#endif
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/* Solaris 10 has no function like this.
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Invoke chmod or lchmod on file, FILE, using mode MODE, in the directory
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open on descriptor FD. If possible, do it without changing the
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working directory. Otherwise, resort to using save_cwd/fchdir,
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then mkdir/restore_cwd. If either the save_cwd or the restore_cwd
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fails, then give a diagnostic and exit nonzero.
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Note that an attempt to use a FLAG value of AT_SYMLINK_NOFOLLOW
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on a system without lchmod support causes this function to fail. */
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int
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fchmodat (int fd, char const *file, mode_t mode, 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 || IS_ABSOLUTE_FILE_NAME (file))
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return (flag == AT_SYMLINK_NOFOLLOW
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? lchmod (file, mode)
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: chmod (file, mode));
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{
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char *proc_file;
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BUILD_PROC_NAME (proc_file, fd, file);
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err = (flag == AT_SYMLINK_NOFOLLOW
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? lchmod (proc_file, mode)
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: chmod (proc_file, mode));
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/* If the syscall succeeds, or if it fails with an unexpected
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errno value, then return right away. Otherwise, fall through
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and resort to using save_cwd/restore_cwd. */
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if (0 <= err || ! EXPECTED_ERRNO (errno))
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return err;
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}
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if (save_cwd (&saved_cwd) != 0)
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openat_save_fail (errno);
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err = fchdir (fd);
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saved_errno = errno;
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if (! err)
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{
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err = (flag == AT_SYMLINK_NOFOLLOW
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? lchmod (file, mode)
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: chmod (file, 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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}
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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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