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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "MasterPTY.h"
#include "PTYMultiplexer.h"
#include "SlavePTY.h"
#include <Kernel/Process.h>
#include <LibC/errno_numbers.h>
#include <LibC/signal_numbers.h>
#include <LibC/sys/ioctl_numbers.h>
//#define MASTERPTY_DEBUG
namespace Kernel {
MasterPTY::MasterPTY(unsigned index)
: CharacterDevice(200, index)
, m_slave(adopt(*new SlavePTY(*this, index)))
, m_index(index)
{
m_pts_name = String::format("/dev/pts/%u", m_index);
set_uid(Process::current->uid());
set_gid(Process::current->gid());
}
MasterPTY::~MasterPTY()
{
#ifdef MASTERPTY_DEBUG
dbgprintf("~MasterPTY(%u)\n", m_index);
#endif
PTYMultiplexer::the().notify_master_destroyed({}, m_index);
}
String MasterPTY::pts_name() const
{
return m_pts_name;
}
ssize_t MasterPTY::read(FileDescription&, u8* buffer, ssize_t size)
{
if (!m_slave && m_buffer.is_empty())
return 0;
return m_buffer.read(buffer, size);
}
ssize_t MasterPTY::write(FileDescription&, const u8* buffer, ssize_t size)
{
if (!m_slave)
return -EIO;
m_slave->on_master_write(buffer, size);
return size;
}
bool MasterPTY::can_read(const FileDescription&) const
{
if (!m_slave)
return true;
return !m_buffer.is_empty();
}
bool MasterPTY::can_write(const FileDescription&) const
{
return true;
}
void MasterPTY::notify_slave_closed(Badge<SlavePTY>)
{
#ifdef MASTERPTY_DEBUG
dbgprintf("MasterPTY(%u): slave closed, my retains: %u, slave retains: %u\n", m_index, ref_count(), m_slave->ref_count());
#endif
// +1 ref for my MasterPTY::m_slave
// +1 ref for FileDescription::m_device
if (m_slave->ref_count() == 2)
m_slave = nullptr;
}
ssize_t MasterPTY::on_slave_write(const u8* data, ssize_t size)
{
if (m_closed)
return -EIO;
m_buffer.write(data, size);
return size;
}
bool MasterPTY::can_write_from_slave() const
{
if (m_closed)
return true;
return m_buffer.space_for_writing();
}
void MasterPTY::close()
{
if (ref_count() == 2) {
InterruptDisabler disabler;
// After the closing FileDescription dies, slave is the only thing keeping me alive.
// From this point, let's consider ourselves closed.
m_closed = true;
m_slave->hang_up();
}
}
int MasterPTY::ioctl(FileDescription& description, unsigned request, unsigned arg)
{
REQUIRE_PROMISE(tty);
if (!m_slave)
return -EIO;
if (request == TIOCSWINSZ || request == TIOCGPGRP)
return m_slave->ioctl(description, request, arg);
return -EINVAL;
}
String MasterPTY::absolute_path(const FileDescription&) const
{
return String::format("ptm:%s", m_pts_name.characters());
}
}
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