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 #include <unistd.h>
22 
23 /*
24  * TEMP_FAILURE_RETRY is defined by some, but not all, versions of
25  * <unistd.h>. (Alas, it is not as standard as we'd hoped!) So, if it's
26  * not already defined, then define it here.
27  */
28 #ifndef TEMP_FAILURE_RETRY
29 /* Used to retry syscalls that can return EINTR. */
30 #define TEMP_FAILURE_RETRY(exp) ({         \
31     typeof (exp) _rc;                      \
32     do {                                   \
33         _rc = (exp);                       \
34     } while (_rc == -1 && errno == EINTR); \
35     _rc; })
36 #endif
37 
38 #ifdef __cplusplus
39 extern "C" {
40 #endif
41 
42 /*
43  * Ensure that directory exists with given mode and owners.  If it exists
44  * with a different mode or owners, they are fixed to match the given values.
45  */
46 extern int fs_prepare_dir(const char* path, mode_t mode, uid_t uid, gid_t gid);
47 
48 /*
49  * Ensure that directory exists with given mode and owners.  If it exists
50  * with different owners, they are not fixed and -1 is returned.
51  */
52 extern int fs_prepare_dir_strict(const char* path, mode_t mode, uid_t uid, gid_t gid);
53 
54 /*
55  * Ensure that file exists with given mode and owners.  If it exists
56  * with different owners, they are not fixed and -1 is returned.
57  */
58 extern int fs_prepare_file_strict(const char* path, mode_t mode, uid_t uid, gid_t gid);
59 
60 
61 /*
62  * Read single plaintext integer from given file, correctly handling files
63  * partially written with fs_write_atomic_int().
64  */
65 extern int fs_read_atomic_int(const char* path, int* value);
66 
67 /*
68  * Write single plaintext integer to given file, creating backup while
69  * in progress.
70  */
71 extern int fs_write_atomic_int(const char* path, int value);
72 
73 /*
74  * Ensure that all directories along given path exist, creating parent
75  * directories as needed.  Validates that given path is absolute and that
76  * it contains no relative "." or ".." paths or symlinks.  Last path segment
77  * is treated as filename and ignored, unless the path ends with "/".
78  */
79 extern int fs_mkdirs(const char* path, mode_t mode);
80 
81 #ifdef __cplusplus
82 }
83 #endif
84 
85 #endif /* __CUTILS_FS_H */
86