1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "base/sync_socket.h" 6 7 #include <errno.h> 8 #include <fcntl.h> 9 #include <limits.h> 10 #include <stdio.h> 11 #include <sys/ioctl.h> 12 #include <sys/socket.h> 13 #include <sys/types.h> 14 15 #if defined(OS_SOLARIS) 16 #include <sys/filio.h> 17 #endif 18 19 #include "base/files/file_util.h" 20 #include "base/logging.h" 21 #include "base/threading/thread_restrictions.h" 22 23 namespace base { 24 25 namespace { 26 // To avoid users sending negative message lengths to Send/Receive 27 // we clamp message lengths, which are size_t, to no more than INT_MAX. 28 const size_t kMaxMessageLength = static_cast<size_t>(INT_MAX); 29 30 // Writes |length| of |buffer| into |handle|. Returns the number of bytes 31 // written or zero on error. |length| must be greater than 0. 32 size_t SendHelper(SyncSocket::Handle handle, 33 const void* buffer, 34 size_t length) { 35 DCHECK_GT(length, 0u); 36 DCHECK_LE(length, kMaxMessageLength); 37 DCHECK_NE(handle, SyncSocket::kInvalidHandle); 38 const char* charbuffer = static_cast<const char*>(buffer); 39 const int len = WriteFileDescriptor(handle, charbuffer, length); 40 return len < 0 ? 0 : static_cast<size_t>(len); 41 } 42 43 bool CloseHandle(SyncSocket::Handle handle) { 44 if (handle != SyncSocket::kInvalidHandle && close(handle) < 0) { 45 DPLOG(ERROR) << "close"; 46 return false; 47 } 48 49 return true; 50 } 51 52 } // namespace 53 54 const SyncSocket::Handle SyncSocket::kInvalidHandle = -1; 55 56 SyncSocket::SyncSocket() : handle_(kInvalidHandle) {} 57 58 SyncSocket::~SyncSocket() { 59 Close(); 60 } 61 62 // static 63 bool SyncSocket::CreatePair(SyncSocket* socket_a, SyncSocket* socket_b) { 64 DCHECK_NE(socket_a, socket_b); 65 DCHECK_EQ(socket_a->handle_, kInvalidHandle); 66 DCHECK_EQ(socket_b->handle_, kInvalidHandle); 67 68 #if defined(OS_MACOSX) 69 int nosigpipe = 1; 70 #endif // defined(OS_MACOSX) 71 72 Handle handles[2] = { kInvalidHandle, kInvalidHandle }; 73 if (socketpair(AF_UNIX, SOCK_STREAM, 0, handles) != 0) { 74 CloseHandle(handles[0]); 75 CloseHandle(handles[1]); 76 return false; 77 } 78 79 #if defined(OS_MACOSX) 80 // On OSX an attempt to read or write to a closed socket may generate a 81 // SIGPIPE rather than returning -1. setsockopt will shut this off. 82 if (0 != setsockopt(handles[0], SOL_SOCKET, SO_NOSIGPIPE, 83 &nosigpipe, sizeof nosigpipe) || 84 0 != setsockopt(handles[1], SOL_SOCKET, SO_NOSIGPIPE, 85 &nosigpipe, sizeof nosigpipe)) { 86 CloseHandle(handles[0]); 87 CloseHandle(handles[1]); 88 return false; 89 } 90 #endif 91 92 // Copy the handles out for successful return. 93 socket_a->handle_ = handles[0]; 94 socket_b->handle_ = handles[1]; 95 96 return true; 97 } 98 99 // static 100 SyncSocket::Handle SyncSocket::UnwrapHandle( 101 const TransitDescriptor& descriptor) { 102 return descriptor.fd; 103 } 104 105 bool SyncSocket::PrepareTransitDescriptor(ProcessHandle peer_process_handle, 106 TransitDescriptor* descriptor) { 107 descriptor->fd = handle(); 108 descriptor->auto_close = false; 109 return descriptor->fd != kInvalidHandle; 110 } 111 112 bool SyncSocket::Close() { 113 const bool retval = CloseHandle(handle_); 114 handle_ = kInvalidHandle; 115 return retval; 116 } 117 118 size_t SyncSocket::Send(const void* buffer, size_t length) { 119 ThreadRestrictions::AssertIOAllowed(); 120 return SendHelper(handle_, buffer, length); 121 } 122 123 size_t SyncSocket::Receive(void* buffer, size_t length) { 124 ThreadRestrictions::AssertIOAllowed(); 125 DCHECK_GT(length, 0u); 126 DCHECK_LE(length, kMaxMessageLength); 127 DCHECK_NE(handle_, kInvalidHandle); 128 char* charbuffer = static_cast<char*>(buffer); 129 if (ReadFromFD(handle_, charbuffer, length)) 130 return length; 131 return 0; 132 } 133 134 size_t SyncSocket::ReceiveWithTimeout(void* buffer, 135 size_t length, 136 TimeDelta timeout) { 137 ThreadRestrictions::AssertIOAllowed(); 138 DCHECK_GT(length, 0u); 139 DCHECK_LE(length, kMaxMessageLength); 140 DCHECK_NE(handle_, kInvalidHandle); 141 142 // TODO(dalecurtis): There's an undiagnosed issue on OSX where we're seeing 143 // large numbers of open files which prevents select() from being used. In 144 // this case, the best we can do is Peek() to see if we can Receive() now or 145 // return a timeout error (0) if not. See http://crbug.com/314364. 146 if (handle_ >= FD_SETSIZE) 147 return Peek() < length ? 0 : Receive(buffer, length); 148 149 // Only timeouts greater than zero and less than one second are allowed. 150 DCHECK_GT(timeout.InMicroseconds(), 0); 151 DCHECK_LT(timeout.InMicroseconds(), 152 base::TimeDelta::FromSeconds(1).InMicroseconds()); 153 154 // Track the start time so we can reduce the timeout as data is read. 155 TimeTicks start_time = TimeTicks::Now(); 156 const TimeTicks finish_time = start_time + timeout; 157 158 fd_set read_fds; 159 size_t bytes_read_total; 160 for (bytes_read_total = 0; 161 bytes_read_total < length && timeout.InMicroseconds() > 0; 162 timeout = finish_time - base::TimeTicks::Now()) { 163 FD_ZERO(&read_fds); 164 FD_SET(handle_, &read_fds); 165 166 // Wait for data to become available. 167 struct timeval timeout_struct = 168 { 0, static_cast<suseconds_t>(timeout.InMicroseconds()) }; 169 const int select_result = 170 select(handle_ + 1, &read_fds, NULL, NULL, &timeout_struct); 171 // Handle EINTR manually since we need to update the timeout value. 172 if (select_result == -1 && errno == EINTR) 173 continue; 174 if (select_result <= 0) 175 return bytes_read_total; 176 177 // select() only tells us that data is ready for reading, not how much. We 178 // must Peek() for the amount ready for reading to avoid blocking. 179 DCHECK(FD_ISSET(handle_, &read_fds)); 180 const size_t bytes_to_read = std::min(Peek(), length - bytes_read_total); 181 182 // There may be zero bytes to read if the socket at the other end closed. 183 if (!bytes_to_read) 184 return bytes_read_total; 185 186 const size_t bytes_received = 187 Receive(static_cast<char*>(buffer) + bytes_read_total, bytes_to_read); 188 bytes_read_total += bytes_received; 189 if (bytes_received != bytes_to_read) 190 return bytes_read_total; 191 } 192 193 return bytes_read_total; 194 } 195 196 size_t SyncSocket::Peek() { 197 DCHECK_NE(handle_, kInvalidHandle); 198 int number_chars = 0; 199 if (ioctl(handle_, FIONREAD, &number_chars) == -1) { 200 // If there is an error in ioctl, signal that the channel would block. 201 return 0; 202 } 203 DCHECK_GE(number_chars, 0); 204 return number_chars; 205 } 206 207 CancelableSyncSocket::CancelableSyncSocket() {} 208 CancelableSyncSocket::CancelableSyncSocket(Handle handle) 209 : SyncSocket(handle) { 210 } 211 212 bool CancelableSyncSocket::Shutdown() { 213 DCHECK_NE(handle_, kInvalidHandle); 214 return HANDLE_EINTR(shutdown(handle_, SHUT_RDWR)) >= 0; 215 } 216 217 size_t CancelableSyncSocket::Send(const void* buffer, size_t length) { 218 DCHECK_GT(length, 0u); 219 DCHECK_LE(length, kMaxMessageLength); 220 DCHECK_NE(handle_, kInvalidHandle); 221 222 const long flags = fcntl(handle_, F_GETFL, NULL); 223 if (flags != -1 && (flags & O_NONBLOCK) == 0) { 224 // Set the socket to non-blocking mode for sending if its original mode 225 // is blocking. 226 fcntl(handle_, F_SETFL, flags | O_NONBLOCK); 227 } 228 229 const size_t len = SendHelper(handle_, buffer, length); 230 231 if (flags != -1 && (flags & O_NONBLOCK) == 0) { 232 // Restore the original flags. 233 fcntl(handle_, F_SETFL, flags); 234 } 235 236 return len; 237 } 238 239 // static 240 bool CancelableSyncSocket::CreatePair(CancelableSyncSocket* socket_a, 241 CancelableSyncSocket* socket_b) { 242 return SyncSocket::CreatePair(socket_a, socket_b); 243 } 244 245 } // namespace base 246
