1 /* Define an at-style functions like fstatat, unlinkat, fchownat, etc.
2 Copyright (C) 2006, 2009 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* written by Jim Meyering */
19 #ifdef AT_FUNC_USE_F1_COND
20 # define CALL_FUNC(F) \
21 (flag == AT_FUNC_USE_F1_COND \
22 ? AT_FUNC_F1 (F AT_FUNC_POST_FILE_ARGS) \
23 : AT_FUNC_F2 (F AT_FUNC_POST_FILE_ARGS))
24 # define VALIDATE_FLAG(F) \
25 if (flag & ~AT_FUNC_USE_F1_COND) \
31 # define CALL_FUNC(F) (AT_FUNC_F1 (F AT_FUNC_POST_FILE_ARGS))
32 # define VALIDATE_FLAG(F) /* empty */
35 /* Call AT_FUNC_F1 to operate on FILE, which is in the directory
36 open on descriptor FD. If AT_FUNC_USE_F1_COND is defined to a value,
37 AT_FUNC_POST_FILE_PARAM_DECLS must inlude a parameter named flag;
38 call AT_FUNC_F2 if FLAG is 0 or fail if FLAG contains more bits than
39 AT_FUNC_USE_F1_COND. If possible, do it without changing the
40 working directory. Otherwise, resort to using save_cwd/fchdir,
41 then AT_FUNC_F?/restore_cwd. If either the save_cwd or the restore_cwd
42 fails, then give a diagnostic and exit nonzero. */
44 AT_FUNC_NAME (int fd, char const *file AT_FUNC_POST_FILE_PARAM_DECLS)
46 struct saved_cwd saved_cwd;
52 if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file))
53 return CALL_FUNC (file);
56 char buf[OPENAT_BUFFER_SIZE];
57 char *proc_file = openat_proc_name (buf, fd, file);
60 int proc_result = CALL_FUNC (proc_file);
61 int proc_errno = errno;
64 /* If the syscall succeeds, or if it fails with an unexpected
65 errno value, then return right away. Otherwise, fall through
66 and resort to using save_cwd/restore_cwd. */
69 if (! EXPECTED_ERRNO (proc_errno))
77 if (save_cwd (&saved_cwd) != 0)
78 openat_save_fail (errno);
83 free_cwd (&saved_cwd);
88 err = CALL_FUNC (file);
89 saved_errno = (err < 0 ? errno : 0);
91 if (restore_cwd (&saved_cwd) != 0)
92 openat_restore_fail (errno);
94 free_cwd (&saved_cwd);