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- /*
- * Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #include <AK/Checked.h>
- #include <LibCore/Socket.h>
- #include <LibIPC/Message.h>
- #include <sched.h>
- namespace IPC {
- using MessageSizeType = u32;
- MessageBuffer::MessageBuffer()
- {
- m_data.resize(sizeof(MessageSizeType));
- }
- ErrorOr<void> MessageBuffer::extend_data_capacity(size_t capacity)
- {
- TRY(m_data.try_ensure_capacity(m_data.size() + capacity));
- return {};
- }
- ErrorOr<void> MessageBuffer::append_data(u8 const* values, size_t count)
- {
- TRY(m_data.try_append(values, count));
- return {};
- }
- ErrorOr<void> MessageBuffer::append_file_descriptor(int fd)
- {
- auto auto_fd = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) AutoCloseFileDescriptor(fd)));
- TRY(m_fds.try_append(move(auto_fd)));
- return {};
- }
- ErrorOr<void> MessageBuffer::transfer_message(Core::LocalSocket& fd_passing_socket, Core::LocalSocket& data_socket)
- {
- Checked<MessageSizeType> checked_message_size { m_data.size() };
- checked_message_size -= sizeof(MessageSizeType);
- if (checked_message_size.has_overflow())
- return Error::from_string_literal("Message is too large for IPC encoding");
- auto message_size = checked_message_size.value();
- m_data.span().overwrite(0, reinterpret_cast<u8 const*>(&message_size), sizeof(message_size));
- for (auto const& fd : m_fds)
- TRY(fd_passing_socket.send_fd(fd->value()));
- ReadonlyBytes bytes_to_write { m_data.span() };
- size_t writes_done = 0;
- while (!bytes_to_write.is_empty()) {
- auto maybe_nwritten = data_socket.write_some(bytes_to_write);
- ++writes_done;
- if (maybe_nwritten.is_error()) {
- if (auto error = maybe_nwritten.release_error(); error.is_errno()) {
- // FIXME: This is a hacky way to at least not crash on large messages
- // The limit of 100 writes is arbitrary, and there to prevent indefinite spinning on the EventLoop
- if (error.code() == EAGAIN && writes_done < 100) {
- sched_yield();
- continue;
- }
- switch (error.code()) {
- case EPIPE:
- return Error::from_string_literal("IPC::transfer_message: Disconnected from peer");
- case EAGAIN:
- return Error::from_string_literal("IPC::transfer_message: Peer buffer overflowed");
- default:
- return Error::from_syscall("IPC::transfer_message write"sv, -error.code());
- }
- } else {
- return error;
- }
- }
- bytes_to_write = bytes_to_write.slice(maybe_nwritten.value());
- }
- if (writes_done > 1) {
- dbgln("LibIPC::transfer_message FIXME Warning, needed {} writes needed to send message of size {}B, this is pretty bad, as it spins on the EventLoop", writes_done, m_data.size());
- }
- return {};
- }
- }
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