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// Copyright 2012 The Chromium Authors
// 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 "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"
#if BUILDFLAG(IS_SOLARIS)
#include <sys/filio.h>
#endif
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