Files
serenity/Kernel/Devices/TTY/PTYMultiplexer.cpp
Liav A. 16244c490a Kernel: Allocate all device major numbers within one known header file
We used to allocate major numbers quite randomly, with no common place
to look them up if needed.
This commit is changing that by placing all major number allocations
under a new C++ namespace, in the API/MajorNumberAllocation.h file.

We also add the foundations of what is needed before we can publish this
information (allocated numbers for block and char devices) to userspace.
2024-07-06 21:42:32 +02:00

67 lines
1.9 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Singleton.h>
#include <Kernel/API/MajorNumberAllocation.h>
#include <Kernel/API/POSIX/errno.h>
#include <Kernel/Debug.h>
#include <Kernel/Devices/TTY/MasterPTY.h>
#include <Kernel/Devices/TTY/PTYMultiplexer.h>
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/Sections.h>
namespace Kernel {
static Singleton<PTYMultiplexer> s_the;
PTYMultiplexer& PTYMultiplexer::the()
{
return *s_the;
}
UNMAP_AFTER_INIT PTYMultiplexer::PTYMultiplexer()
: CharacterDevice(MajorAllocation::CharacterDeviceFamily::Console, 2)
{
m_freelist.with([&](auto& freelist) {
freelist.ensure_capacity(max_pty_pairs);
for (int i = max_pty_pairs; i > 0; --i)
freelist.unchecked_append(i - 1);
});
}
UNMAP_AFTER_INIT PTYMultiplexer::~PTYMultiplexer() = default;
UNMAP_AFTER_INIT void PTYMultiplexer::initialize()
{
MUST(the().after_inserting());
}
ErrorOr<NonnullRefPtr<OpenFileDescription>> PTYMultiplexer::open(int options)
{
return m_freelist.with([&](auto& freelist) -> ErrorOr<NonnullRefPtr<OpenFileDescription>> {
if (freelist.is_empty())
return EBUSY;
auto master_index = freelist.take_last();
auto master = TRY(MasterPTY::try_create(master_index));
dbgln_if(PTMX_DEBUG, "PTYMultiplexer::open: Vending master {}", master->index());
auto description = TRY(OpenFileDescription::try_create(*master));
description->set_rw_mode(options);
description->set_file_flags(options);
return description;
});
}
void PTYMultiplexer::notify_master_destroyed(Badge<MasterPTY>, unsigned index)
{
m_freelist.with([&](auto& freelist) {
freelist.append(index);
dbgln_if(PTMX_DEBUG, "PTYMultiplexer: {} added to freelist", index);
});
}
}