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 32 File* OS::OpenFileForReading(const char* name) { 33 return OpenFileWithFlags(name, O_RDONLY); 34 } 35 36 File* OS::OpenFileReadWrite(const char* name) { 37 return OpenFileWithFlags(name, O_RDWR); 38 } 39 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 48 File* OS::CreateEmptyFile(const char* name) { 49 return art::CreateEmptyFile(name, O_RDWR | O_TRUNC); 50 } 51 52 File* OS::CreateEmptyFileWriteOnly(const char* name) { 53 return art::CreateEmptyFile(name, O_WRONLY | O_TRUNC | O_NOFOLLOW | O_CLOEXEC); 54 } 55 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(new File(name, flags, 0666, check_usage)); 61 if (!file->IsOpened()) { 62 return nullptr; 63 } 64 return file.release(); 65 } 66 67 bool OS::FileExists(const char* name, bool check_file_type) { 68 struct stat st; 69 if (stat(name, &st) == 0) { 70 if (check_file_type) { 71 return S_ISREG(st.st_mode); // TODO: Deal with symlinks? 72 } else { 73 return true; 74 } 75 } else { 76 return false; 77 } 78 } 79 80 bool OS::DirectoryExists(const char* name) { 81 struct stat st; 82 if (stat(name, &st) == 0) { 83 return S_ISDIR(st.st_mode); // TODO: Deal with symlinks? 84 } else { 85 return false; 86 } 87 } 88 89 int64_t OS::GetFileSizeBytes(const char* name) { 90 struct stat st; 91 if (stat(name, &st) == 0) { 92 return st.st_size; // TODO: Deal with symlinks? According to the documentation, 93 // the st_size for a symlink is "the length of the pathname 94 // it contains, without a terminating null byte." 95 } else { 96 return -1; 97 } 98 } 99 100 } // namespace art 101
