RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 04:47:35 +00:00
Code Issues Activity Actions

LibIPC+LibWeb: Add an IPC helper to transfer an IPC message buffer

Browse source 
This large block of code is repeated nearly verbatim in LibWeb. Move it
to a helper function that both LibIPC and LibWeb can defer to. This will
let us make changes to this method in a singular location going forward.

Note this is a bit of a regression for the MessagePort. It now suffers
from the same performance issue that IPC messages face - we prepend the
meessage size to the message buffer. This degredation is very temporary
though, as a fix is imminent, and this change makes that fix easier.
This commit is contained in:
Timothy Flynn 2024-01-02 20:14:18 -05:00 • committed by Andreas Kling
parent bf15b66117
commit 91558fa381
6 changed files with 72 additions and 91 deletions
Download patch file Download diff file Expand all files Collapse all files

48
Userland/Libraries/LibIPC/Connection.cpp
View file

@ -8,7 +8,6 @@
#include <LibCore/System.h>
#include <LibIPC/Connection.h>
#include <LibIPC/Stub.h>
#include <sched.h>
#include <sys/select.h>
namespace IPC {
@ -60,50 +59,9 @@ ErrorOr<void> ConnectionBase::post_message(MessageBuffer buffer)
if (!m_socket->is_open())
return Error::from_string_literal("Trying to post_message during IPC shutdown");
// Prepend the message size.
uint32_t message_size = buffer.data.size();
TRY(buffer.data.try_prepend(reinterpret_cast<u8 const*>(&message_size), sizeof(message_size)));
for (auto& fd : buffer.fds) {
if (auto result = fd_passing_socket().send_fd(fd->value()); result.is_error()) {
shutdown_with_error(result.error());
return result;
}
}
ReadonlyBytes bytes_to_write { buffer.data.span() };
int writes_done = 0;
size_t initial_size = bytes_to_write.size();
while (!bytes_to_write.is_empty()) {
auto maybe_nwritten = m_socket->write_some(bytes_to_write);
writes_done++;
if (maybe_nwritten.is_error()) {
auto error = maybe_nwritten.release_error();
if (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;
}
shutdown_with_error(error);
switch (error.code()) {
case EPIPE:
return Error::from_string_literal("IPC::Connection::post_message: Disconnected from peer");
case EAGAIN:
return Error::from_string_literal("IPC::Connection::post_message: Peer buffer overflowed");
default:
return Error::from_syscall("IPC::Connection::post_message write"sv, -error.code());
}
} else {
return error;
}
}
bytes_to_write = bytes_to_write.slice(maybe_nwritten.value());
}
if (writes_done > 1) {
dbgln("LibIPC::Connection FIXME Warning, needed {} writes needed to send message of size {}B, this is pretty bad, as it spins on the EventLoop", writes_done, initial_size);
if (auto result = buffer.transfer_message(fd_passing_socket(), *m_socket); result.is_error()) {
shutdown_with_error(result.error());
return result.release_error();
}
m_responsiveness_timer->start();