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 "os.h"
18 
19 #include <sys/types.h>
20 #include <sys/stat.h>
21 #include <fcntl.h>
22 #include <cstddef>
23 #include <memory>
24 
25 #include "base/logging.h"
26 #include "base/unix_file/fd_file.h"
27 
28 namespace art {
29 
OpenFileForReading(const char * name)30 File* OS::OpenFileForReading(const char* name) {
31   return OpenFileWithFlags(name, O_RDONLY);
32 }
33 
OpenFileReadWrite(const char * name)34 File* OS::OpenFileReadWrite(const char* name) {
35   return OpenFileWithFlags(name, O_RDWR);
36 }
37 
CreateEmptyFile(const char * name,int extra_flags)38 static File* CreateEmptyFile(const char* name, int extra_flags) {
39   // In case the file exists, unlink it so we get a new file. This is necessary as the previous
40   // file may be in use and must not be changed.
41   unlink(name);
42 
43   return OS::OpenFileWithFlags(name, O_CREAT | extra_flags);
44 }
45 
CreateEmptyFile(const char * name)46 File* OS::CreateEmptyFile(const char* name) {
47   return art::CreateEmptyFile(name, O_RDWR | O_TRUNC);
48 }
49 
CreateEmptyFileWriteOnly(const char * name)50 File* OS::CreateEmptyFileWriteOnly(const char* name) {
51   return art::CreateEmptyFile(name, O_WRONLY | O_TRUNC | O_NOFOLLOW | O_CLOEXEC);
52 }
53 
OpenFileWithFlags(const char * name,int flags)54 File* OS::OpenFileWithFlags(const char* name, int flags) {
55   CHECK(name != nullptr);
56   std::unique_ptr<File> file(new File);
57   if (!file->Open(name, flags, 0666)) {
58     return nullptr;
59   }
60   return file.release();
61 }
62 
FileExists(const char * name)63 bool OS::FileExists(const char* name) {
64   struct stat st;
65   if (stat(name, &st) == 0) {
66     return S_ISREG(st.st_mode);  // TODO: Deal with symlinks?
67   } else {
68     return false;
69   }
70 }
71 
DirectoryExists(const char * name)72 bool OS::DirectoryExists(const char* name) {
73   struct stat st;
74   if (stat(name, &st) == 0) {
75     return S_ISDIR(st.st_mode);  // TODO: Deal with symlinks?
76   } else {
77     return false;
78   }
79 }
80 
81 }  // namespace art
82