tomaswolf opened a new issue, #266: URL: https://github.com/apache/mina-sshd/issues/266
The ultimate problem is a general one concerning ChannelExecs: If * there is a communication protocol implemented between the client and the remote command via the stdin/stdout streams, * and if the protocol is such that the remote command can return an error code _in this application protocol_, * and the client uses the default inverted output stream to read that error code, * and the client then decides to close the channel (even gracefully), then it is possible that the `AbstractClientChannel`'s `out` stream is closed between lines [436](https://github.com/apache/mina-sshd/blob/a85d0743/sshd-core/src/main/java/org/apache/sshd/client/channel/AbstractClientChannel.java#L436) and 437, and then the `flush()`call on the `ChannelPipedOutputStream` may fail, causing the whole session to go down. This can happen in the `ScpTest`at line [343](https://github.com/apache/mina-sshd/blob/a85d0743e/sshd-scp/src/test/java/org/apache/sshd/scp/client/ScpTest.java#L343), which tests an scp upload command that should fail. The scp server sends back an ERROR ack, which the client reads (on an I/O thread) and forwards in `AbstractClientChannel`. The client reads this though the `ChannelPipedInputStream` (on the main thread) and throws an exception, which then causes the channel to be closed at the end of `DefaultScpClient.runUpload()` (still on the main thread). Only then does the I/O thread call `flush()`, which then fails with an exception. So in short we have 1. I/O thread: receive data 2. I/O thread: write data to `ChannelPipedOutputStream` 3. Main thread: read data from `ChannelPipedInputStream` 4. Main thread: close channel 5. I/O thread: call `ChannelPipedOutputStream.flush()` and fail. This is all the more infuriating since `ChannelPipedOutputStream.flush()` is essentially a no-op. Moreover: an exception when a channel has received data and tries to forward it should not take down the whole session but only this channel. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: dev-unsubscr...@mina.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@mina.apache.org For additional commands, e-mail: dev-h...@mina.apache.org
