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 #include <algorithm> 18 #include <cerrno> 19 #include <cstdint> 20 #include <cstring> 21 22 #include "android-base/logging.h" 23 24 #include "wifilogd/local_utils.h" 25 #include "wifilogd/os.h" 26 27 namespace android { 28 namespace wifilogd { 29 30 using local_utils::GetMaxVal; 31 32 namespace { 33 constexpr auto kMaxNanoSeconds = 1000 * 1000 * 1000 - 1; 34 } 35 36 constexpr int Os::kInvalidFd; 37 38 Os::Os() : raw_os_(new RawOs()) {} 39 Os::Os(std::unique_ptr<RawOs> raw_os) : raw_os_(std::move(raw_os)) {} 40 Os::~Os() {} 41 42 std::tuple<int, Os::Errno> Os::GetControlSocket( 43 const std::string& socket_name) { 44 int sock_fd = raw_os_->GetControlSocket(socket_name.c_str()); 45 if (sock_fd < 0) { 46 return {kInvalidFd, errno}; 47 } else { 48 return {sock_fd, 0}; 49 } 50 } 51 52 Os::Timestamp Os::GetTimestamp(clockid_t clock_id) const { 53 struct timespec now_timespec; 54 int failed = raw_os_->ClockGettime(clock_id, &now_timespec); 55 if (failed) { 56 LOG(FATAL) << "Unexpected error: " << std::strerror(errno); 57 } 58 CHECK(now_timespec.tv_nsec <= kMaxNanoSeconds); 59 60 Timestamp now_timestamp; 61 now_timestamp.secs = SAFELY_CLAMP( 62 now_timespec.tv_sec, uint32_t, 0, 63 // The upper-bound comes from the source-type on 32-bit platforms, 64 // and the dest-type on 64-bit platforms. Using min(), we can figure out 65 // which type to use for the upper bound, without resorting to macros. 66 std::min(static_cast<uintmax_t>(GetMaxVal(now_timestamp.secs)), 67 static_cast<uintmax_t>(GetMaxVal(now_timespec.tv_sec)))); 68 now_timestamp.nsecs = 69 SAFELY_CLAMP(now_timespec.tv_nsec, uint32_t, 0, kMaxNanoSeconds); 70 return now_timestamp; 71 } 72 73 void Os::Nanosleep(uint32_t sleep_time_nsec) { 74 struct timespec sleep_timespec = { 75 0, // tv_sec 76 SAFELY_CLAMP(sleep_time_nsec, decltype(timespec::tv_nsec), 0, kMaxNanos)}; 77 78 int failed = 0; 79 do { 80 struct timespec remaining_timespec; 81 failed = raw_os_->Nanosleep(&sleep_timespec, &remaining_timespec); 82 sleep_timespec = remaining_timespec; 83 } while (failed && errno == EINTR && sleep_timespec.tv_nsec > 0); 84 85 if (failed && errno != EINTR) { 86 // The only other documented errors for the underlying nanosleep() call are 87 // EFAULT and EINVAL. But we always pass valid pointers, and the values in 88 // |sleep_timespec| are always valid. 89 LOG(FATAL) << "Unexpected error: " << std::strerror(errno); 90 } 91 } 92 93 std::tuple<size_t, Os::Errno> Os::ReceiveDatagram(int fd, void* buf, 94 size_t buflen) { 95 // recv() takes a size_t, but returns an ssize_t. That means that the largest 96 // successful read that recv() can report is the maximal ssize_t. Passing a 97 // larger |buflen| risks mistakenly reporting a truncated read. 98 CHECK(buflen <= GetMaxVal<ssize_t>()); 99 100 const ssize_t res = raw_os_->Recv(fd, buf, buflen, MSG_TRUNC); 101 if (res < 0) { 102 return {0, errno}; 103 } 104 105 // Due to the MSG_TRUNC flag, |res| may reasonably be larger than 106 // |buflen|. In such cases, |res| indicates the full size of the datagram, 107 // before being truncated to fit our buffer. Hence, we omit the 108 // buffer-overflow CHECK that exists in Write(). 109 return {res, 0}; 110 } 111 112 std::tuple<size_t, Os::Errno> Os::Write(int fd, const void* buf, 113 size_t buflen) { 114 // write() takes a size_t, but returns an ssize_t. That means that the 115 // largest successful write that write() can report is the maximal ssize_t. 116 // Passing a larger |buflen| risks mistakenly reporting a truncated write. 117 CHECK(buflen <= GetMaxVal<ssize_t>()); 118 119 const ssize_t res = raw_os_->Write(fd, buf, buflen); 120 if (res < 0) { 121 return {0, errno}; 122 } 123 124 CHECK(res <= 125 SAFELY_CLAMP(buflen, ssize_t, 0, 126 GetMaxVal<ssize_t>())); // Abort on buffer overflow. 127 128 // Note that |res| may be less than buflen. However, a) a short write is 129 // not an error, and b) |errno| may be stale, as |errno| is only guaranteed to 130 // be set if an error occurred. Hence, we return Errno of 0 unconditionally. 131 // See http://yarchive.net/comp/linux/write_error_return.html 132 return {res, 0}; 133 } 134 135 } // namespace wifilogd 136 } // namespace android 137
