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It can be accessed and reviewed at: https://github.com/lxc/lxd/pull/7827
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=== Description (from pull-request) ===
From what I've tested and understand, the `ExecInstance` function can be called with a boolean `Interactive` flag.
* When the flag is on :
* `stderr` and `stdout` are both merged to a `stdout` reader (so there is no way to know the source)
* unix signals can be sent to the process
* When the flag is off :
* `stderr` and `stdout` are kept separated using two distinct readers
* unix signals are received, but not executed
So since, I would like to keep `stderr` and `stdout` separated AND the ability to send signals to the running process, I've added some code to handle the signals in the non-interactive case.
From dfdef9e7c3dd17b1d48c85ae6eba35186f84056b Mon Sep 17 00:00:00 2001
From: Pierre Gleize <gleize.pie...@gmail.com>
Date: Fri, 28 Aug 2020 11:29:17 -0700
Subject: [PATCH] Handle signals in non-interactive sessions.
---
lxd/instance_exec.go | 66 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)
diff --git a/lxd/instance_exec.go b/lxd/instance_exec.go
index da59162df3..a1959a14b7 100644
--- a/lxd/instance_exec.go
+++ b/lxd/instance_exec.go
@@ -336,6 +336,72 @@ func (s *execWs) Do(op *operations.Operation) error {
}
}(i)
}
+ wgEOF.Add(1)
+ go func() {
+ defer wgEOF.Done()
+
+ logger.Debug("Non-Interactive child process handler
started")
+ defer logger.Debug("Non-Interactive child process
handler finished")
+
+ select {
+ case <-s.controlConnected:
+ break
+ case <-controlExit:
+ return
+ }
+
+ for {
+ s.connsLock.Lock()
+ conn := s.conns[-1]
+ s.connsLock.Unlock()
+
+ mt, r, err := conn.NextReader()
+ if mt == websocket.CloseMessage {
+ break
+ }
+
+ if err != nil {
+ logger.Debug("Got error getting next
reader", log.Ctx{"err": err})
+ er, ok := err.(*websocket.CloseError)
+ if !ok {
+ break
+ }
+
+ if er.Code !=
websocket.CloseAbnormalClosure {
+ break
+ }
+
+ // If an abnormal closure occurred,
kill the attached child.
+ err := cmd.Signal(unix.SIGKILL)
+ if err != nil {
+ logger.Debug("Failed to send
SIGKILL signal", log.Ctx{"err": err})
+ } else {
+ logger.Debug("Sent SIGKILL
signal")
+ }
+ return
+ }
+
+ buf, err := ioutil.ReadAll(r)
+ if err != nil {
+ logger.Debug("Failed to read message",
log.Ctx{"err": err})
+ break
+ }
+
+ command := api.InstanceExecControl{}
+
+ if err := json.Unmarshal(buf, &command); err !=
nil {
+ logger.Debug("Failed to unmarshal
control socket command", log.Ctx{"err": err})
+ continue
+ }
+ if command.Command == "signal" {
+ err :=
cmd.Signal(unix.Signal(command.Signal))
+ if err != nil {
+ logger.Debug("Failed forwarding
signal", log.Ctx{"err": err, "signal": command.Signal})
+ continue
+ }
+ }
+ }
+ }()
}
exitCode, err := cmd.Wait()
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