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/*
* Copyright © Canonical Ltd.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 or 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <mir/test/cross_process_sync.h>
#include <boost/exception/info.hpp>
#include <system_error>
#include <poll.h>
#include <unistd.h>
namespace mt = mir::test;
namespace
{
const int read_fd = 0;
const int write_fd = 1;
struct UnexpectedValueErrorInfoTag {};
typedef boost::error_info<UnexpectedValueErrorInfoTag, unsigned int> errinfo_unexpected_value;
}
mt::CrossProcessSync::CrossProcessSync() : counter(0)
{
if (::pipe(fds) < 0)
{
BOOST_THROW_EXCEPTION(std::system_error(errno,
std::system_category(),
"Failed to create pipe"));
}
}
mt::CrossProcessSync::CrossProcessSync(const CrossProcessSync& rhs) : counter(rhs.counter)
{
fds[0] = ::dup(rhs.fds[0]);
fds[1] = ::dup(rhs.fds[1]);
}
mt::CrossProcessSync::~CrossProcessSync() noexcept
{
::close(fds[0]);
::close(fds[1]);
}
mt::CrossProcessSync& mt::CrossProcessSync::operator=(const mt::CrossProcessSync& rhs)
{
::close(fds[0]);
::close(fds[1]);
fds[0] = ::dup(rhs.fds[0]);
fds[1] = ::dup(rhs.fds[1]);
counter = rhs.counter;
return *this;
}
void mt::CrossProcessSync::try_signal_ready_for()
{
try_signal_ready_for(std::chrono::minutes(2));
}
void mt::CrossProcessSync::try_signal_ready_for(const std::chrono::milliseconds& duration)
{
static const short empty_revents = 0;
pollfd poll_fd[1] = { { fds[write_fd], POLLOUT, empty_revents } };
int rc = -1;
while ((rc = ::poll(poll_fd, 1, duration.count())) <= 0)
{
if (errno == EINTR)
{
continue;
}
if (rc == 0)
{
BOOST_THROW_EXCEPTION(std::runtime_error("Poll on writefd for pipe timed out"));
}
else
{
BOOST_THROW_EXCEPTION(std::system_error(errno, std::system_category(), "Error while polling pipe to become writable"));
}
}
int value = 1;
if (sizeof(value) != write(fds[write_fd], std::addressof(value), sizeof(value)))
{
BOOST_THROW_EXCEPTION(std::system_error(errno,
std::system_category(),
"Error while writing to pipe"));
}
}
unsigned int mt::CrossProcessSync::wait_for_signal_ready_for()
{
return wait_for_signal_ready_for(std::chrono::minutes(2));
}
unsigned int mt::CrossProcessSync::wait_for_signal_ready_for(const std::chrono::milliseconds& duration)
{
static const short empty_revents = 0;
pollfd poll_fd[1] = { { fds[read_fd], POLLIN, empty_revents } };
int rc = -1;
while ((rc = ::poll(poll_fd, 1, duration.count())) <= 0)
{
if (errno == EINTR)
{
continue;
}
if (rc == 0)
{
BOOST_THROW_EXCEPTION(std::runtime_error("Poll on readfd for pipe timed out"));
}
else
{
BOOST_THROW_EXCEPTION(std::system_error(errno, std::system_category(), "Error while polling pipe to become readable"));
}
}
int value;
if (sizeof(value) != read(fds[read_fd], std::addressof(value), sizeof(value)))
{
BOOST_THROW_EXCEPTION(std::system_error(errno,
std::system_category(),
"Error while reading from pipe"));
}
if (value != 1)
{
BOOST_THROW_EXCEPTION(
::boost::enable_error_info(std::runtime_error("Read an unexpected value from pipe"))
<< errinfo_unexpected_value(value));
}
counter += value;
return counter;
}
void mt::CrossProcessSync::signal_ready()
{
try_signal_ready_for(std::chrono::milliseconds{-1});
}
unsigned int mt::CrossProcessSync::wait_for_signal_ready()
{
return wait_for_signal_ready_for(std::chrono::milliseconds{-1});
}
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