base/sync_socket_posix.cc

   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