Ladybird/ladybird
1
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2025-06-11 18:20:43 +09:00
Code Activity

LibIPC+Meta: Keep message buffer alive until acknowledged by peer

Browse source 
This change ensures that instead of immediately deallocating the message
buffer after sending, we retain it in an acknowledgement wait queue
until an acknowledgement is received from the peer. This is necessary
to handle a behavior of the macOS kernel, which may prematurely
garbage-collect file descriptors contained within the message buffer
before the peer receives them.

The acknowledgement mechanism assumes messages are received in the same
order they were sent so, each acknowledgement message simply indicates
the count of successfully received messages, specifying how many entries
can safely be removed from the acknowledgement wait queue.
This commit is contained in:
Aliaksandr Kalenik 2025-04-05 00:05:20 +02:00 • committed by Andreas Kling
parent 15e2c78e9a
commit c3121c9d8a
Notes: github-actions[bot] 2025-04-05 21:15:26 +00:00
5 changed files with 121 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

28
Libraries/LibIPC/Message.cpp
View file

@ -111,4 +111,32 @@ ErrorOr<NonnullOwnPtr<LargeMessageWrapper>> LargeMessageWrapper::decode(u32 endp
return make<LargeMessageWrapper>(endpoint_magic, wrapped_message_data, move(wrapped_fds));
}
Acknowledgement::Acknowledgement(u32 endpoint_magic, u32 ack_count)
: m_endpoint_magic(endpoint_magic)
, m_ack_count(ack_count)
{
}
NonnullOwnPtr<Acknowledgement> Acknowledgement::create(u32 endpoint_magic, u32 ack_count)
{
return make<Acknowledgement>(endpoint_magic, ack_count);
}
ErrorOr<MessageBuffer> Acknowledgement::encode() const
{
MessageBuffer buffer;
Encoder stream { buffer };
TRY(stream.encode(m_endpoint_magic));
TRY(stream.encode(MESSAGE_ID));
TRY(stream.encode(m_ack_count));
return buffer;
}
ErrorOr<NonnullOwnPtr<Acknowledgement>> Acknowledgement::decode(u32 endpoint_magic, Stream& stream, UnprocessedFileDescriptors& files)
{
Decoder decoder { stream, files };
auto ack_count = TRY(decoder.decode<u32>());
return make<Acknowledgement>(endpoint_magic, ack_count);
}
}