1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef __CUTILS_FS_H
18#define __CUTILS_FS_H
19
20#include <sys/types.h>
21
22/*
23 * TEMP_FAILURE_RETRY is defined by some, but not all, versions of
24 * <unistd.h>. (Alas, it is not as standard as we'd hoped!) So, if it's
25 * not already defined, then define it here.
26 */
27#ifndef TEMP_FAILURE_RETRY
28/* Used to retry syscalls that can return EINTR. */
29#define TEMP_FAILURE_RETRY(exp) ({         \
30    typeof (exp) _rc;                      \
31    do {                                   \
32        _rc = (exp);                       \
33    } while (_rc == -1 && errno == EINTR); \
34    _rc; })
35#endif
36
37#ifdef __cplusplus
38extern "C" {
39#endif
40
41/*
42 * Ensure that directory exists with given mode and owners.
43 */
44extern int fs_prepare_dir(const char* path, mode_t mode, uid_t uid, gid_t gid);
45
46/*
47 * Read single plaintext integer from given file, correctly handling files
48 * partially written with fs_write_atomic_int().
49 */
50extern int fs_read_atomic_int(const char* path, int* value);
51
52/*
53 * Write single plaintext integer to given file, creating backup while
54 * in progress.
55 */
56extern int fs_write_atomic_int(const char* path, int value);
57
58#ifdef __cplusplus
59}
60#endif
61
62#endif /* __CUTILS_FS_H */
63