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serenity/Kernel/TTY/MasterPTY.cpp
Andreas Kling 94ca55cefd Meta: Add license header to source files
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.

For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.

Going forward, all new source files should include a license header.
2020-01-18 09:45:54 +01:00

138 lines
4 KiB
C++

/*
* 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
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(current->process().uid());
set_gid(current->process().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.bytes_in_write_buffer() < 4096;
}
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());
}