1 /*
2 * Copyright (C) 2005 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 #pragma once
17
18 #include <sys/stat.h>
19 #include <time.h>
20
21 //
22 // Handy utility functions and portability code.
23 //
24
25 namespace android {
26
27 /*
28 * Some utility functions for working with files. These could be made
29 * part of a "File" class.
30 */
31 typedef enum FileType {
32 kFileTypeUnknown = 0,
33 kFileTypeNonexistent, // i.e. ENOENT
34 kFileTypeRegular,
35 kFileTypeDirectory,
36 kFileTypeCharDev,
37 kFileTypeBlockDev,
38 kFileTypeFifo,
39 kFileTypeSymlink,
40 kFileTypeSocket,
41 } FileType;
42 /* get the file's type; follows symlinks */
43 FileType getFileType(const char* fileName);
44
45 // MinGW doesn't support nanosecond resolution in stat() modification time, and given
46 // that it only matters on the device it's ok to keep it at a seconds level there.
47 #ifdef _WIN32
48 using ModDate = time_t;
49 inline constexpr ModDate kInvalidModDate = ModDate(-1);
50 inline constexpr unsigned long long kModDateResolutionNs = 1ull * 1000 * 1000 * 1000;
toTimeT(ModDate m)51 inline time_t toTimeT(ModDate m) {
52 return m;
53 }
54 #else
55 using ModDate = timespec;
56 inline constexpr ModDate kInvalidModDate = {-1, -1};
57 inline constexpr unsigned long long kModDateResolutionNs = 1;
toTimeT(ModDate m)58 inline time_t toTimeT(ModDate m) {
59 return m.tv_sec;
60 }
61 #endif
62
63 /* get the file's modification date; returns kInvalidModDate w/errno set on failure */
64 ModDate getFileModDate(const char* fileName);
65 /* same, but also returns -1 if the file has already been deleted */
66 ModDate getFileModDate(int fd);
67
68 // Extract the modification date from the stat structure.
69 ModDate getModDate(const struct ::stat& st);
70
71 // Check if |path| or |fd| resides on a readonly filesystem.
72 bool isReadonlyFilesystem(const char* path);
73 bool isReadonlyFilesystem(int fd);
74
75 bool isKnownWritablePath(const char* path);
76
77 } // namespace android
78
79 // Whoever uses getFileModDate() will need this as well
80 inline bool operator==(const timespec& l, const timespec& r) {
81 return l.tv_sec == r.tv_sec && l.tv_nsec == r.tv_nsec;
82 }
83