- Closes#712.
- Replace synchronous `write()` calls in
`BidirectionalRelay` with non-blocking I/O
and `DispatchSourceWrite` backpressure
handling. Under concurrent vsock proxy load,
a single blocked write on the shared serial
dispatch queue would freeze all relay
connections permanently, including unrelated
new connections.
- Set relay file descriptors to `O_NONBLOCK`
and handle `EAGAIN` by suspending reads and
installing a write source to drain pending data.
- Give each `BidirectionalRelay` its own serial queue
instead of sharing one from `UnixSocketRelayManager`,
eliminating cross-connection blocking.
- Resume suspended read sources before cancelling
in `stop()` — GCD does not deliver cancel handlers
on suspended dispatch sources, which caused file
descriptor and memory leaks on teardown under
backpressure.
- Guard-unwrap `buf.baseAddress` in
`drainPendingWrite`.
This helps on binary size if we can successfully get all Foundation
imports out of our dep chain. It seems Foundation brings in a 30MiB ICU
blob, which bloats vmexec and vminitd.
- Downgrades a warning to the debug level in `BidirectionalRelay`
because the shutdown syscall isn't supported for certain socket types
- Rethrows an error if we can't start a socket relay
- Adds a public method to wait for the relay to complete when both
directions close
- Improves error handling
- Moves `UnixSocketRelayManager` into a separate file
- Renames `SocketRelay` to `UnixSocketRelay`
- Adds logs at the info level after converting other logs to the debug
level previously
Changes:
- Refactors a bidirectional relay into a new class
- Makes the unique identifier for a socket configuration public
Bug fixes:
- Fixes a bug where partial writes didn't advance the pointer
- Fixes a buffer memory leak
- Fixes error messages
- Fixes log messages
- Fixes log levels
mlsad3