1 /*
2 * Copyright (C) 2010 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 #include "base/os.h"
18
19 #include <fcntl.h>
20 #include <sys/stat.h>
21 #include <sys/types.h>
22
23 #include <cstddef>
24 #include <memory>
25
26 #include <android-base/logging.h>
27
28 #include "base/unix_file/fd_file.h"
29
30 namespace art {
31
OpenFileForReading(const char * name)32 File* OS::OpenFileForReading(const char* name) {
33 return OpenFileWithFlags(name, O_RDONLY);
34 }
35
OpenFileReadWrite(const char * name)36 File* OS::OpenFileReadWrite(const char* name) {
37 return OpenFileWithFlags(name, O_RDWR);
38 }
39
CreateEmptyFile(const char * name,int extra_flags)40 static File* CreateEmptyFile(const char* name, int extra_flags) {
41 // In case the file exists, unlink it so we get a new file. This is necessary as the previous
42 // file may be in use and must not be changed.
43 unlink(name);
44
45 return OS::OpenFileWithFlags(name, O_CREAT | extra_flags);
46 }
47
CreateEmptyFile(const char * name)48 File* OS::CreateEmptyFile(const char* name) {
49 return art::CreateEmptyFile(name, O_RDWR | O_TRUNC);
50 }
51
CreateEmptyFileWriteOnly(const char * name)52 File* OS::CreateEmptyFileWriteOnly(const char* name) {
53 return art::CreateEmptyFile(name, O_WRONLY | O_TRUNC | O_NOFOLLOW | O_CLOEXEC);
54 }
55
OpenFileWithFlags(const char * name,int flags,bool auto_flush)56 File* OS::OpenFileWithFlags(const char* name, int flags, bool auto_flush) {
57 CHECK(name != nullptr);
58 bool read_only = ((flags & O_ACCMODE) == O_RDONLY);
59 bool check_usage = !read_only && auto_flush;
60 std::unique_ptr<File> file(
61 new File(name, flags, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH, check_usage));
62 if (!file->IsOpened()) {
63 return nullptr;
64 }
65 return file.release();
66 }
67
FileExists(const char * name,bool check_file_type)68 bool OS::FileExists(const char* name, bool check_file_type) {
69 struct stat st;
70 if (stat(name, &st) == 0) {
71 if (check_file_type) {
72 return S_ISREG(st.st_mode); // TODO: Deal with symlinks?
73 } else {
74 return true;
75 }
76 } else {
77 return false;
78 }
79 }
80
DirectoryExists(const char * name)81 bool OS::DirectoryExists(const char* name) {
82 struct stat st;
83 if (stat(name, &st) == 0) {
84 return S_ISDIR(st.st_mode); // TODO: Deal with symlinks?
85 } else {
86 return false;
87 }
88 }
89
GetFileSizeBytes(const char * name)90 int64_t OS::GetFileSizeBytes(const char* name) {
91 struct stat st;
92 if (stat(name, &st) == 0) {
93 return st.st_size; // TODO: Deal with symlinks? According to the documentation,
94 // the st_size for a symlink is "the length of the pathname
95 // it contains, without a terminating null byte."
96 } else {
97 return -1;
98 }
99 }
100
101 } // namespace art
102