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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 <poll.h>
- #include <stddef.h>
- #include <stdio.h>
- #include <sys/ioctl.h>
- #include <sys/socket.h>
- #include <sys/types.h>
- #include "build/build_config.h"
- #if BUILDFLAG(IS_SOLARIS)
- #include <sys/filio.h>
- #endif
- #include "base/check_op.h"
- #include "base/containers/span.h"
- #include "base/files/file_util.h"
- #include "base/numerics/safe_conversions.h"
- #include "base/threading/scoped_blocking_call.h"
- #include "build/build_config.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);
- return WriteFileDescriptor(
- handle, make_span(static_cast<const uint8_t*>(buffer), length))
- ? length
- : 0;
- }
- } // namespace
- // static
- bool SyncSocket::CreatePair(SyncSocket* socket_a, SyncSocket* socket_b) {
- DCHECK_NE(socket_a, socket_b);
- DCHECK(!socket_a->IsValid());
- DCHECK(!socket_b->IsValid());
- #if BUILDFLAG(IS_APPLE)
- int nosigpipe = 1;
- #endif // BUILDFLAG(IS_APPLE)
- ScopedHandle handles[2];
- {
- Handle raw_handles[2] = {kInvalidHandle, kInvalidHandle};
- if (socketpair(AF_UNIX, SOCK_STREAM, 0, raw_handles) != 0) {
- return false;
- }
- handles[0].reset(raw_handles[0]);
- handles[1].reset(raw_handles[1]);
- }
- #if BUILDFLAG(IS_APPLE)
- // 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].get(), SOL_SOCKET, SO_NOSIGPIPE, &nosigpipe,
- sizeof(nosigpipe)) ||
- 0 != setsockopt(handles[1].get(), SOL_SOCKET, SO_NOSIGPIPE, &nosigpipe,
- sizeof(nosigpipe))) {
- return false;
- }
- #endif
- // Copy the handles out for successful return.
- socket_a->handle_ = std::move(handles[0]);
- socket_b->handle_ = std::move(handles[1]);
- return true;
- }
- void SyncSocket::Close() {
- handle_.reset();
- }
- size_t SyncSocket::Send(const void* buffer, size_t length) {
- ScopedBlockingCall scoped_blocking_call(FROM_HERE, BlockingType::MAY_BLOCK);
- return SendHelper(handle(), buffer, length);
- }
- size_t SyncSocket::Receive(void* buffer, size_t length) {
- ScopedBlockingCall scoped_blocking_call(FROM_HERE, BlockingType::MAY_BLOCK);
- DCHECK_GT(length, 0u);
- DCHECK_LE(length, kMaxMessageLength);
- DCHECK(IsValid());
- 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) {
- ScopedBlockingCall scoped_blocking_call(FROM_HERE, BlockingType::MAY_BLOCK);
- DCHECK_GT(length, 0u);
- DCHECK_LE(length, kMaxMessageLength);
- DCHECK(IsValid());
- // Only timeouts greater than zero and less than one second are allowed.
- DCHECK_GT(timeout.InMicroseconds(), 0);
- DCHECK_LT(timeout.InMicroseconds(), Seconds(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;
- struct pollfd pollfd;
- pollfd.fd = handle();
- pollfd.events = POLLIN;
- pollfd.revents = 0;
- size_t bytes_read_total = 0;
- while (bytes_read_total < length) {
- const TimeDelta this_timeout = finish_time - TimeTicks::Now();
- const int timeout_ms =
- static_cast<int>(this_timeout.InMillisecondsRoundedUp());
- if (timeout_ms <= 0)
- break;
- const int poll_result = poll(&pollfd, 1, timeout_ms);
- // Handle EINTR manually since we need to update the timeout value.
- if (poll_result == -1 && errno == EINTR)
- continue;
- // Return if other type of error or a timeout.
- if (poll_result <= 0)
- return bytes_read_total;
- // poll() only tells us that data is ready for reading, not how much. We
- // must Peek() for the amount ready for reading to avoid blocking.
- // At hang up (POLLHUP), the write end has been closed and there might still
- // be data to be read.
- // No special handling is needed for error (POLLERR); we can let any of the
- // following operations fail and handle it there.
- DCHECK(pollfd.revents & (POLLIN | POLLHUP | POLLERR)) << pollfd.revents;
- 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(IsValid());
- int number_chars = 0;
- if (ioctl(handle_.get(), FIONREAD, &number_chars) == -1) {
- // If there is an error in ioctl, signal that the channel would block.
- return 0;
- }
- return checked_cast<size_t>(number_chars);
- }
- bool SyncSocket::IsValid() const {
- return handle_.is_valid();
- }
- SyncSocket::Handle SyncSocket::handle() const {
- return handle_.get();
- }
- SyncSocket::Handle SyncSocket::Release() {
- return handle_.release();
- }
- bool CancelableSyncSocket::Shutdown() {
- DCHECK(IsValid());
- 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(IsValid());
- const int flags = fcntl(handle(), F_GETFL);
- 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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