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varlink / libvarlink

C implementation of the Varlink protocol and command line tool
Apache License 2.0
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varlink_stream_bridge() will silently discard data #15

Closed thomasjfox closed 3 years ago

thomasjfox commented 4 years ago

lib/stream.c:varlink_stream_bridge() switches the client/server sockets to non-blocking mode. At least the write() call should handle the non-fatal errno codes EAGAIN, EWOULDBLOCK and EINTR from write(). Otherwise silent data loss occurs.

Ideally the read() code does the same, so it doesn't need to re-enter the function to keep bridging data.

I've noticed this issue during a manual audit for these specific problems as we evaluate varlink as our next-gen IPC. We have painful experience with non-blocking sockets for 19+ years ;) We'll probably extend varlink for our use with netstring encapsulation during transport in a backward-compatible way as JSON data always starts with '{' or '['.

haraldh commented 4 years ago

Please review https://github.com/varlink/libvarlink/pull/20