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LibIPC: Fix waiting for specific message

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When waiting for a specific message, only consider messages
from the peer endpoint. Otherwise a message with the same id
for the local endpoint may be misinterpreted.

This fixes the Terminal sometimes hanging after bootup because
a local endpoint message is mistaken for the CreateMenuResponse
message.
This commit is contained in:
Tom 2020-08-02 19:34:09 -06:00 • committed by Andreas Kling
parent c813bb7355
commit 8b0b653471
1 changed files with 30 additions and 24 deletions
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54
Libraries/LibIPC/ServerConnection.h
View file

@ -83,29 +83,7 @@ public:
template<typename MessageType> template<typename MessageType>
OwnPtr<MessageType> wait_for_specific_message() OwnPtr<MessageType> wait_for_specific_message()
{ {
// Double check we don't already have the event waiting for us. return wait_for_specific_endpoint_message<MessageType, LocalEndpoint>();
// Otherwise we might end up blocked for a while for no reason.
for (size_t i = 0; i < m_unprocessed_messages.size(); ++i) {
if (m_unprocessed_messages[i].message_id() == MessageType::static_message_id())
return m_unprocessed_messages.take(i).template release_nonnull<MessageType>();
}
for (;;) {
fd_set rfds;
FD_ZERO(&rfds);
FD_SET(m_connection->fd(), &rfds);
int rc = Core::safe_syscall(select, m_connection->fd() + 1, &rfds, nullptr, nullptr, nullptr);
if (rc < 0) {
perror("select");
}
ASSERT(rc > 0);
ASSERT(FD_ISSET(m_connection->fd(), &rfds));
if (!drain_messages_from_server())
return nullptr;
for (size_t i = 0; i < m_unprocessed_messages.size(); ++i) {
if (m_unprocessed_messages[i].message_id() == MessageType::static_message_id())
return m_unprocessed_messages.take(i).template release_nonnull<MessageType>();
}
}
} }
bool post_message(const Message& message) bool post_message(const Message& message)
@ -126,12 +104,40 @@ public:
{ {
bool success = post_message(RequestType(forward<Args>(args)...)); bool success = post_message(RequestType(forward<Args>(args)...));
ASSERT(success); ASSERT(success);
auto response = wait_for_specific_message<typename RequestType::ResponseType>(); auto response = wait_for_specific_endpoint_message<typename RequestType::ResponseType, PeerEndpoint>();
ASSERT(response); ASSERT(response);
return response; return response;
} }
private: private:
template<typename MessageType, typename Endpoint>
OwnPtr<MessageType> wait_for_specific_endpoint_message()
{
for (;;) {
// Double check we don't already have the event waiting for us.
// Otherwise we might end up blocked for a while for no reason.
for (size_t i = 0; i < m_unprocessed_messages.size(); ++i) {
auto& message = m_unprocessed_messages[i];
if (message.endpoint_magic() != Endpoint::static_magic())
continue;
if (message.message_id() == MessageType::static_message_id())
return m_unprocessed_messages.take(i).template release_nonnull<MessageType>();
}
fd_set rfds;
FD_ZERO(&rfds);
FD_SET(m_connection->fd(), &rfds);
int rc = Core::safe_syscall(select, m_connection->fd() + 1, &rfds, nullptr, nullptr, nullptr);
if (rc < 0) {
perror("select");
}
ASSERT(rc > 0);
ASSERT(FD_ISSET(m_connection->fd(), &rfds));
if (!drain_messages_from_server())
return nullptr;
}
}
bool drain_messages_from_server() bool drain_messages_from_server()
{ {
Vector<u8> bytes; Vector<u8> bytes;