1 /* 2 * Copyright (C) 2016 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 OS_H_ 18 #define OS_H_ 19 20 #include <time.h> 21 22 #include <cstdint> 23 #include <memory> 24 #include <string> 25 #include <tuple> 26 #include <utility> 27 28 #include "android-base/macros.h" 29 30 #include "wifilogd/local_utils.h" 31 #include "wifilogd/raw_os.h" 32 33 namespace android { 34 namespace wifilogd { 35 36 // Abstracts operating system calls. 37 // 38 // There are three reasons we want to abstract OS calls: 39 // 1. Allow tests to run hermetically. 40 // 2. Verify that the application logic invokes the OS calls as expected. 41 // 3. Provide interfaces that as easier to use, than the underlying OS calls. 42 class Os { 43 public: 44 using Errno = int; 45 46 struct Timestamp { 47 uint32_t secs; // Sufficient through 2100. 48 uint32_t nsecs; 49 }; 50 51 static constexpr int kInvalidFd = -1; 52 static constexpr auto kMaxNanos = 999'999'999; 53 54 // Constructs an Os instance. 55 Os(); 56 57 // Constructs an Os instance, with the caller-provided RawOs. This method 58 // allows tests to provide a MockRawOs. 59 explicit Os(std::unique_ptr<RawOs> raw_os); 60 61 virtual ~Os(); 62 63 // Returns the Android control socket with name |socket_name|. If no such 64 // socket exists, or the init daemon has not provided this process with 65 // access to said socket, returns {kInvalidFd, errno}. 66 virtual std::tuple<int, Errno> GetControlSocket( 67 const std::string& socket_name); 68 69 // Returns the current time, as reported by the clock with |clock_id|. 70 virtual Timestamp GetTimestamp(clockid_t clock_id) const; 71 72 // Suspends execution of this process, for |sleep_time_nsec|. The passed 73 // value must not exceed kMaxNanos. 74 virtual void Nanosleep(uint32_t sleep_time_nsec); 75 76 // Receives a datagram of up to |buflen| from |fd|, writing the data to |buf|. 77 // Returns the size of the datagram, and the result of the operation (0 for 78 // success, |errno| otherwise). 79 // 80 // Notes: 81 // - |buflen| may not exceed the maximal value for ssize_t. 82 // - The call blocks until a datagram is available. 83 // - If the datagram is larger than |buflen|, only |buflen| bytes will 84 // be received. The returned size_t will, however, reflect the full 85 // length of the datagram. 86 virtual std::tuple<size_t, Errno> ReceiveDatagram(int fd, NONNULL void* buf, 87 size_t buflen); 88 89 // Writes |buflen| bytes from |buf| to |fd|. Returns the number of bytes 90 // written, and the result of the operation (0 for success, |errno| 91 // otherwise). 92 // 93 // Notes: 94 // - |buflen| may not exceed the maximal value for ssize_t. 95 // - The returned size_t will not exceed |buflen|. 96 virtual std::tuple<size_t, Errno> Write(int fd, NONNULL const void* buf, 97 size_t buflen); 98 99 private: 100 const std::unique_ptr<RawOs> raw_os_; 101 102 DISALLOW_COPY_AND_ASSIGN(Os); 103 }; 104 105 } // namespace wifilogd 106 } // namespace android 107 108 #endif // OS_H_ 109
