ladybird/Kernel/Syscalls/pipe.cpp

58 lines
1.8 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/FileSystem/FIFO.h>
#include <Kernel/Tasks/Process.h>
namespace Kernel {
ErrorOr<FlatPtr> Process::sys$pipe(Userspace<int*> pipefd, int flags)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
// Reject flags other than O_CLOEXEC, O_NONBLOCK
if ((flags & (O_CLOEXEC | O_NONBLOCK)) != flags)
return EINVAL;
u32 fd_flags = (flags & O_CLOEXEC) ? FD_CLOEXEC : 0;
auto credentials = this->credentials();
auto fifo = TRY(FIFO::try_create(credentials->uid()));
auto reader_description = TRY(fifo->open_direction(FIFO::Direction::Reader));
auto writer_description = TRY(fifo->open_direction(FIFO::Direction::Writer));
reader_description->set_readable(true);
writer_description->set_writable(true);
if (flags & O_NONBLOCK) {
reader_description->set_blocking(false);
writer_description->set_blocking(false);
}
TRY(m_fds.with_exclusive([&](auto& fds) -> ErrorOr<void> {
auto reader_fd_allocation = TRY(fds.allocate());
auto writer_fd_allocation = TRY(fds.allocate());
fds[reader_fd_allocation.fd].set(move(reader_description), fd_flags);
fds[writer_fd_allocation.fd].set(move(writer_description), fd_flags);
int fds_for_userspace[2] = {
reader_fd_allocation.fd,
writer_fd_allocation.fd,
};
if (copy_n_to_user(pipefd, fds_for_userspace, 2).is_error()) {
// Avoid leaking both file descriptors on error.
fds[reader_fd_allocation.fd] = {};
fds[writer_fd_allocation.fd] = {};
return EFAULT;
}
return {};
}));
return 0;
}
}