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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/sync_socket.h"
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#if defined(OS_SOLARIS)
#include <sys/filio.h>
#endif
#include "base/files/file_util.h"
#include "base/logging.h"
#include "base/threading/thread_restrictions.h"
namespace base {
namespace {
// To avoid users sending negative message lengths to Send/Receive
// we clamp message lengths, which are size_t, to no more than INT_MAX.
const size_t kMaxMessageLength = static_cast<size_t>(INT_MAX);
// Writes |length| of |buffer| into |handle|. Returns the number of bytes
// written or zero on error. |length| must be greater than 0.
size_t SendHelper(SyncSocket::Handle handle,
const void* buffer,
size_t length) {
DCHECK_GT(length, 0u);
DCHECK_LE(length, kMaxMessageLength);
DCHECK_NE(handle, SyncSocket::kInvalidHandle);
const char* charbuffer = static_cast<const char*>(buffer);
return WriteFileDescriptor(handle, charbuffer, length)
? static_cast<size_t>(length)
: 0;
}
bool CloseHandle(SyncSocket::Handle handle) {
if (handle != SyncSocket::kInvalidHandle && close(handle) < 0) {
DPLOG(ERROR) << "close";
return false;
}
return true;
}
} // namespace
const SyncSocket::Handle SyncSocket::kInvalidHandle = -1;
SyncSocket::SyncSocket() : handle_(kInvalidHandle) {}
SyncSocket::~SyncSocket() {
Close();
}
// static
bool SyncSocket::CreatePair(SyncSocket* socket_a, SyncSocket* socket_b) {
DCHECK_NE(socket_a, socket_b);
DCHECK_EQ(socket_a->handle_, kInvalidHandle);
DCHECK_EQ(socket_b->handle_, kInvalidHandle);
#if defined(OS_MACOSX)
int nosigpipe = 1;
#endif // defined(OS_MACOSX)
Handle handles[2] = { kInvalidHandle, kInvalidHandle };
if (socketpair(AF_UNIX, SOCK_STREAM, 0, handles) != 0) {
CloseHandle(handles[0]);
CloseHandle(handles[1]);
return false;
}
#if defined(OS_MACOSX)
// On OSX an attempt to read or write to a closed socket may generate a
// SIGPIPE rather than returning -1. setsockopt will shut this off.
if (0 != setsockopt(handles[0], SOL_SOCKET, SO_NOSIGPIPE,
&nosigpipe, sizeof nosigpipe) ||
0 != setsockopt(handles[1], SOL_SOCKET, SO_NOSIGPIPE,
&nosigpipe, sizeof nosigpipe)) {
CloseHandle(handles[0]);
CloseHandle(handles[1]);
return false;
}
#endif
// Copy the handles out for successful return.
socket_a->handle_ = handles[0];
socket_b->handle_ = handles[1];
return true;
}
// static
SyncSocket::Handle SyncSocket::UnwrapHandle(
const TransitDescriptor& descriptor) {
return descriptor.fd;
}
bool SyncSocket::PrepareTransitDescriptor(ProcessHandle peer_process_handle,
TransitDescriptor* descriptor) {
descriptor->fd = handle();
descriptor->auto_close = false;
return descriptor->fd != kInvalidHandle;
}
bool SyncSocket::Close() {
const bool retval = CloseHandle(handle_);
handle_ = kInvalidHandle;
return retval;
}
size_t SyncSocket::Send(const void* buffer, size_t length) {
ThreadRestrictions::AssertIOAllowed();
return SendHelper(handle_, buffer, length);
}
size_t SyncSocket::Receive(void* buffer, size_t length) {
ThreadRestrictions::AssertIOAllowed();
DCHECK_GT(length, 0u);
DCHECK_LE(length, kMaxMessageLength);
DCHECK_NE(handle_, kInvalidHandle);
char* charbuffer = static_cast<char*>(buffer);
if (ReadFromFD(handle_, charbuffer, length))
return length;
return 0;
}
size_t SyncSocket::ReceiveWithTimeout(void* buffer,
size_t length,
TimeDelta timeout) {
ThreadRestrictions::AssertIOAllowed();
DCHECK_GT(length, 0u);
DCHECK_LE(length, kMaxMessageLength);
DCHECK_NE(handle_, kInvalidHandle);
// TODO(dalecurtis): There's an undiagnosed issue on OSX where we're seeing
// large numbers of open files which prevents select() from being used. In
// this case, the best we can do is Peek() to see if we can Receive() now or
// return a timeout error (0) if not. See http://crbug.com/314364.
if (handle_ >= FD_SETSIZE)
return Peek() < length ? 0 : Receive(buffer, length);
// Only timeouts greater than zero and less than one second are allowed.
DCHECK_GT(timeout.InMicroseconds(), 0);
DCHECK_LT(timeout.InMicroseconds(),
base::TimeDelta::FromSeconds(1).InMicroseconds());
// Track the start time so we can reduce the timeout as data is read.
TimeTicks start_time = TimeTicks::Now();
const TimeTicks finish_time = start_time + timeout;
fd_set read_fds;
size_t bytes_read_total;
for (bytes_read_total = 0;
bytes_read_total < length && timeout.InMicroseconds() > 0;
timeout = finish_time - base::TimeTicks::Now()) {
FD_ZERO(&read_fds);
FD_SET(handle_, &read_fds);
// Wait for data to become available.
struct timeval timeout_struct =
{ 0, static_cast<suseconds_t>(timeout.InMicroseconds()) };
const int select_result =
select(handle_ + 1, &read_fds, NULL, NULL, &timeout_struct);
// Handle EINTR manually since we need to update the timeout value.
if (select_result == -1 && errno == EINTR)
continue;
if (select_result <= 0)
return bytes_read_total;
// select() only tells us that data is ready for reading, not how much. We
// must Peek() for the amount ready for reading to avoid blocking.
DCHECK(FD_ISSET(handle_, &read_fds));
const size_t bytes_to_read = std::min(Peek(), length - bytes_read_total);
// There may be zero bytes to read if the socket at the other end closed.
if (!bytes_to_read)
return bytes_read_total;
const size_t bytes_received =
Receive(static_cast<char*>(buffer) + bytes_read_total, bytes_to_read);
bytes_read_total += bytes_received;
if (bytes_received != bytes_to_read)
return bytes_read_total;
}
return bytes_read_total;
}
size_t SyncSocket::Peek() {
DCHECK_NE(handle_, kInvalidHandle);
int number_chars = 0;
if (ioctl(handle_, FIONREAD, &number_chars) == -1) {
// If there is an error in ioctl, signal that the channel would block.
return 0;
}
DCHECK_GE(number_chars, 0);
return number_chars;
}
CancelableSyncSocket::CancelableSyncSocket() {}
CancelableSyncSocket::CancelableSyncSocket(Handle handle)
: SyncSocket(handle) {
}
bool CancelableSyncSocket::Shutdown() {
DCHECK_NE(handle_, kInvalidHandle);
return HANDLE_EINTR(shutdown(handle_, SHUT_RDWR)) >= 0;
}
size_t CancelableSyncSocket::Send(const void* buffer, size_t length) {
DCHECK_GT(length, 0u);
DCHECK_LE(length, kMaxMessageLength);
DCHECK_NE(handle_, kInvalidHandle);
const long flags = fcntl(handle_, F_GETFL, NULL);
if (flags != -1 && (flags & O_NONBLOCK) == 0) {
// Set the socket to non-blocking mode for sending if its original mode
// is blocking.
fcntl(handle_, F_SETFL, flags | O_NONBLOCK);
}
const size_t len = SendHelper(handle_, buffer, length);
if (flags != -1 && (flags & O_NONBLOCK) == 0) {
// Restore the original flags.
fcntl(handle_, F_SETFL, flags);
}
return len;
}
// static
bool CancelableSyncSocket::CreatePair(CancelableSyncSocket* socket_a,
CancelableSyncSocket* socket_b) {
return SyncSocket::CreatePair(socket_a, socket_b);
}
} // namespace base
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