ladybird/Kernel/TTY/MasterPTY.cpp
Andreas Kling e9dda8d592 Kernel: Give PTY's *actually* unique major ID's
Okay, one "dunce hat" point for me. The new PTY majors conflicted with
PATAChannel. Now they are 200 for master and 201 for slave, not used
by anything else.. I hope!
2019-12-09 21:03:39 +01:00

111 lines
2.6 KiB
C++

#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)
{
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());
}