ladybird/Kernel/Syscalls/pipe.cpp

56 lines
1.7 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/FileSystem/FIFO.h>
#include <Kernel/Process.h>
namespace Kernel {
KResultOr<FlatPtr> Process::sys$pipe(int pipefd[2], int flags)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(stdio);
if (fds().open_count() + 2 > fds().max_open())
return EMFILE;
// Reject flags other than O_CLOEXEC.
if ((flags & O_CLOEXEC) != flags)
return EINVAL;
u32 fd_flags = (flags & O_CLOEXEC) ? FD_CLOEXEC : 0;
auto fifo = FIFO::try_create(uid());
if (!fifo)
return ENOMEM;
auto open_reader_result = fifo->open_direction(FIFO::Direction::Reader);
if (open_reader_result.is_error())
return open_reader_result.error();
auto open_writer_result = fifo->open_direction(FIFO::Direction::Writer);
if (open_writer_result.is_error())
return open_writer_result.error();
auto reader_fd_or_error = m_fds.allocate();
if (reader_fd_or_error.is_error())
return reader_fd_or_error.error();
auto reader_fd = reader_fd_or_error.release_value();
m_fds[reader_fd.fd].set(open_reader_result.release_value(), fd_flags);
m_fds[reader_fd.fd].description()->set_readable(true);
if (!copy_to_user(&pipefd[0], &reader_fd.fd))
return EFAULT;
auto writer_fd_or_error = m_fds.allocate();
if (writer_fd_or_error.is_error())
return writer_fd_or_error.error();
auto writer_fd = writer_fd_or_error.release_value();
m_fds[writer_fd.fd].set(open_writer_result.release_value(), fd_flags);
m_fds[writer_fd.fd].description()->set_writable(true);
if (!copy_to_user(&pipefd[1], &writer_fd.fd))
return EFAULT;
return 0;
}
}