(mina-sshd) 01/03: AbstractClientChannel: fix waiting for channel having closed

[twolf]

This is an automated email from the ASF dual-hosted git repository.

twolf pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mina-sshd.git

commit 1b9084f2fdc0d53822cdb423332d74ca1d84b288
Author: Thomas Wolf <tw...@apache.org>
AuthorDate: Tue Mar 12 22:11:17 2024 +0100

    AbstractClientChannel: fix waiting for channel having closed
    
    channel.waitFor(EnumSet.of(ClientChannelEvent.CLOSED), timeout) would
    not wait until the channel was closed, but would return with the CLOSED
    event already when the channel was still closing.
    
    The closeSignaled flag was set already in preClose(), but at that point
    the SSH_MSG_CHANNEL_CLOSE handshake still had to be done. In the common
    usage of
    ```
    try  (ClientSession session = ...) {
      // Authenticate, then:
      try (ChannelExec channel = session.createExecChannel(...)) {
        // Open the channel, perhaps do something with input/output streams
        // ...
        Collection<ClientChannelEvent> result =
            channel.waitFor(numSet.of(ClientChannelEvent.CLOSED), timeout);
      }
    }
    ```
    the call to waitFor() would return early already when the server's
    SSH_MSG_CHANNEL_CLOSE was received, but before the client's reply was
    sent.
    
    The thread executing this code would then close the channel and then
    the session, which results in a race with sending that client reply out.
    If the session got closed first, the client would log an exception about
    a write attempt on a closed session.
    
    Fix this by removing closeSignaled.get() from the conditions for being
    in CLOSED state. The state is not CLOSED yet; it would be IS_CLOSING at
    best.
---
 .../main/java/org/apache/sshd/client/channel/AbstractClientChannel.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git 
a/sshd-core/src/main/java/org/apache/sshd/client/channel/AbstractClientChannel.java
 
b/sshd-core/src/main/java/org/apache/sshd/client/channel/AbstractClientChannel.java
index a3ed6ffb6..fd12580de 100644
--- 
a/sshd-core/src/main/java/org/apache/sshd/client/channel/AbstractClientChannel.java
+++ 
b/sshd-core/src/main/java/org/apache/sshd/client/channel/AbstractClientChannel.java
@@ -323,7 +323,7 @@ public abstract class AbstractClientChannel extends 
AbstractChannel implements C
         if ((openFuture != null) && openFuture.isOpened()) {
             state.add(ClientChannelEvent.OPENED);
         }
-        if (closeFuture.isClosed() || closeSignaled.get() || 
unregisterSignaled.get() || isClosed()) {
+        if (closeFuture.isClosed() || unregisterSignaled.get() || isClosed()) {
             state.add(ClientChannelEvent.CLOSED);
         }
         if (isEofSignalled()) {