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   return WriteFileDescriptor(handle, charbuffer, length)
  40              ? static_cast<size_t>(length)
  41              : 0;
  42 }
  43
  44 bool CloseHandle(SyncSocket::Handle handle) {
  45   if (handle != SyncSocket::kInvalidHandle && close(handle) < 0) {
  46     DPLOG(ERROR) << "close";
  47     return false;
  48   }
  49
  50   return true;
  51 }
  52
  53 }  // namespace
  54
  55 const SyncSocket::Handle SyncSocket::kInvalidHandle = -1;
  56
  57 SyncSocket::SyncSocket() : handle_(kInvalidHandle) {}
  58
  59 SyncSocket::~SyncSocket() {
  60   Close();
  61 }
  62
  63 // static
  64 bool SyncSocket::CreatePair(SyncSocket* socket_a, SyncSocket* socket_b) {
  65   DCHECK_NE(socket_a, socket_b);
  66   DCHECK_EQ(socket_a->handle_, kInvalidHandle);
  67   DCHECK_EQ(socket_b->handle_, kInvalidHandle);
  68
  69 #if defined(OS_MACOSX)
  70   int nosigpipe = 1;
  71 #endif  // defined(OS_MACOSX)
  72
  73   Handle handles[2] = { kInvalidHandle, kInvalidHandle };
  74   if (socketpair(AF_UNIX, SOCK_STREAM, 0, handles) != 0) {
  75     CloseHandle(handles[0]);
  76     CloseHandle(handles[1]);
  77     return false;
  78   }
  79
  80 #if defined(OS_MACOSX)
  81   // On OSX an attempt to read or write to a closed socket may generate a
  82   // SIGPIPE rather than returning -1.  setsockopt will shut this off.
  83   if (0 != setsockopt(handles[0], SOL_SOCKET, SO_NOSIGPIPE,
  84                       &nosigpipe, sizeof nosigpipe) ||
  85       0 != setsockopt(handles[1], SOL_SOCKET, SO_NOSIGPIPE,
  86                       &nosigpipe, sizeof nosigpipe)) {
  87     CloseHandle(handles[0]);
  88     CloseHandle(handles[1]);
  89     return false;
  90   }
  91 #endif
  92
  93   // Copy the handles out for successful return.
  94   socket_a->handle_ = handles[0];
  95   socket_b->handle_ = handles[1];
  96
  97   return true;
  98 }
  99
 100 // static
 101 SyncSocket::Handle SyncSocket::UnwrapHandle(
 102     const TransitDescriptor& descriptor) {
 103   return descriptor.fd;
 104 }
 105
 106 bool SyncSocket::PrepareTransitDescriptor(ProcessHandle peer_process_handle,
 107                                           TransitDescriptor* descriptor) {
 108   descriptor->fd = handle();
 109   descriptor->auto_close = false;
 110   return descriptor->fd != kInvalidHandle;
 111 }
 112
 113 bool SyncSocket::Close() {
 114   const bool retval = CloseHandle(handle_);
 115   handle_ = kInvalidHandle;
 116   return retval;
 117 }
 118
 119 size_t SyncSocket::Send(const void* buffer, size_t length) {
 120   ThreadRestrictions::AssertIOAllowed();
 121   return SendHelper(handle_, buffer, length);
 122 }
 123
 124 size_t SyncSocket::Receive(void* buffer, size_t length) {
 125   ThreadRestrictions::AssertIOAllowed();
 126   DCHECK_GT(length, 0u);
 127   DCHECK_LE(length, kMaxMessageLength);
 128   DCHECK_NE(handle_, kInvalidHandle);
 129   char* charbuffer = static_cast<char*>(buffer);
 130   if (ReadFromFD(handle_, charbuffer, length))
 131     return length;
 132   return 0;
 133 }
 134
 135 size_t SyncSocket::ReceiveWithTimeout(void* buffer,
 136                                       size_t length,
 137                                       TimeDelta timeout) {
 138   ThreadRestrictions::AssertIOAllowed();
 139   DCHECK_GT(length, 0u);
 140   DCHECK_LE(length, kMaxMessageLength);
 141   DCHECK_NE(handle_, kInvalidHandle);
 142
 143   // TODO(dalecurtis): There's an undiagnosed issue on OSX where we're seeing
 144   // large numbers of open files which prevents select() from being used.  In
 145   // this case, the best we can do is Peek() to see if we can Receive() now or
 146   // return a timeout error (0) if not.  See http://crbug.com/314364.
 147   if (handle_ >= FD_SETSIZE)
 148     return Peek() < length ? 0 : Receive(buffer, length);
 149
 150   // Only timeouts greater than zero and less than one second are allowed.
 151   DCHECK_GT(timeout.InMicroseconds(), 0);
 152   DCHECK_LT(timeout.InMicroseconds(),
 153             base::TimeDelta::FromSeconds(1).InMicroseconds());
 154
 155   // Track the start time so we can reduce the timeout as data is read.
 156   TimeTicks start_time = TimeTicks::Now();
 157   const TimeTicks finish_time = start_time + timeout;
 158
 159   fd_set read_fds;
 160   size_t bytes_read_total;
 161   for (bytes_read_total = 0;
 162        bytes_read_total < length && timeout.InMicroseconds() > 0;
 163        timeout = finish_time - base::TimeTicks::Now()) {
 164     FD_ZERO(&read_fds);
 165     FD_SET(handle_, &read_fds);
 166
 167     // Wait for data to become available.
 168     struct timeval timeout_struct =
 169         { 0, static_cast<suseconds_t>(timeout.InMicroseconds()) };
 170     const int select_result =
 171         select(handle_ + 1, &read_fds, NULL, NULL, &timeout_struct);
 172     // Handle EINTR manually since we need to update the timeout value.
 173     if (select_result == -1 && errno == EINTR)
 174       continue;
 175     if (select_result <= 0)
 176       return bytes_read_total;
 177
 178     // select() only tells us that data is ready for reading, not how much.  We
 179     // must Peek() for the amount ready for reading to avoid blocking.
 180     DCHECK(FD_ISSET(handle_, &read_fds));
 181     const size_t bytes_to_read = std::min(Peek(), length - bytes_read_total);
 182
 183     // There may be zero bytes to read if the socket at the other end closed.
 184     if (!bytes_to_read)
 185       return bytes_read_total;
 186
 187     const size_t bytes_received =
 188         Receive(static_cast<char*>(buffer) + bytes_read_total, bytes_to_read);
 189     bytes_read_total += bytes_received;
 190     if (bytes_received != bytes_to_read)
 191       return bytes_read_total;
 192   }
 193
 194   return bytes_read_total;
 195 }
 196
 197 size_t SyncSocket::Peek() {
 198   DCHECK_NE(handle_, kInvalidHandle);
 199   int number_chars = 0;
 200   if (ioctl(handle_, FIONREAD, &number_chars) == -1) {
 201     // If there is an error in ioctl, signal that the channel would block.
 202     return 0;
 203   }
 204   DCHECK_GE(number_chars, 0);
 205   return number_chars;
 206 }
 207
 208 CancelableSyncSocket::CancelableSyncSocket() {}
 209 CancelableSyncSocket::CancelableSyncSocket(Handle handle)
 210     : SyncSocket(handle) {
 211 }
 212
 213 bool CancelableSyncSocket::Shutdown() {
 214   DCHECK_NE(handle_, kInvalidHandle);
 215   return HANDLE_EINTR(shutdown(handle_, SHUT_RDWR)) >= 0;
 216 }
 217
 218 size_t CancelableSyncSocket::Send(const void* buffer, size_t length) {
 219   DCHECK_GT(length, 0u);
 220   DCHECK_LE(length, kMaxMessageLength);
 221   DCHECK_NE(handle_, kInvalidHandle);
 222
 223   const long flags = fcntl(handle_, F_GETFL, NULL);
 224   if (flags != -1 && (flags & O_NONBLOCK) == 0) {
 225     // Set the socket to non-blocking mode for sending if its original mode
 226     // is blocking.
 227     fcntl(handle_, F_SETFL, flags | O_NONBLOCK);
 228   }
 229
 230   const size_t len = SendHelper(handle_, buffer, length);
 231
 232   if (flags != -1 && (flags & O_NONBLOCK) == 0) {
 233     // Restore the original flags.
 234     fcntl(handle_, F_SETFL, flags);
 235   }
 236
 237   return len;
 238 }
 239
 240 // static
 241 bool CancelableSyncSocket::CreatePair(CancelableSyncSocket* socket_a,
 242                                       CancelableSyncSocket* socket_b) {
 243   return SyncSocket::CreatePair(socket_a, socket_b);
 244 }
 245
 246 }  // namespace base