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 */
36 # define FUNC_RESULT AT_FUNC_RESULT
38 # define FUNC_RESULT int
41 /* Call AT_FUNC_F1 to operate on FILE, which is in the directory
42 open on descriptor FD. If AT_FUNC_USE_F1_COND is defined to a value,
43 AT_FUNC_POST_FILE_PARAM_DECLS must inlude a parameter named flag;
44 call AT_FUNC_F2 if FLAG is 0 or fail if FLAG contains more bits than
45 AT_FUNC_USE_F1_COND. If possible, do it without changing the
46 working directory. Otherwise, resort to using save_cwd/fchdir,
47 then AT_FUNC_F?/restore_cwd. If either the save_cwd or the restore_cwd
48 fails, then give a diagnostic and exit nonzero. */
50 AT_FUNC_NAME (int fd, char const *file AT_FUNC_POST_FILE_PARAM_DECLS)
52 /* Be careful to choose names unlikely to conflict with
53 AT_FUNC_POST_FILE_PARAM_DECLS. */
54 struct saved_cwd saved_cwd;
60 if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file))
61 return CALL_FUNC (file);
64 char proc_buf[OPENAT_BUFFER_SIZE];
65 char *proc_file = openat_proc_name (proc_buf, fd, file);
68 FUNC_RESULT proc_result = CALL_FUNC (proc_file);
69 int proc_errno = errno;
70 if (proc_file != proc_buf)
72 /* If the syscall succeeds, or if it fails with an unexpected
73 errno value, then return right away. Otherwise, fall through
74 and resort to using save_cwd/restore_cwd. */
77 if (! EXPECTED_ERRNO (proc_errno))
85 if (save_cwd (&saved_cwd) != 0)
86 openat_save_fail (errno);
91 free_cwd (&saved_cwd);
96 err = CALL_FUNC (file);
97 saved_errno = (err < 0 ? errno : 0);
99 if (restore_cwd (&saved_cwd) != 0)
100 openat_restore_fail (errno);
102 free_cwd (&saved_cwd);