[PATCH] util: virExec may blocked by reading pipe if grandchild prematurely exit

[Yi Wang <wang.yi59@xxxxxxxxxx>]

From: Xu Chao <xu.chao6@xxxxxxxxxx>

When VIR_EXEC_DAEMON is set, if virPidFileAcquirePath/virSetInherit failed,
then pipesync[0] can not be closed when granchild process exit, because
pipesync[1] still opened in child process. and then saferead in child
process may blocked forever, and left grandchild process in defunct state.

Signed-off-by: Xu Chao <xu.chao6@xxxxxxxxxx>
Signed-off-by: Yi Wang <wang.yi59@xxxxxxxxxx>
---
 src/util/vircommand.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/util/vircommand.c b/src/util/vircommand.c
index fead373729..fa71f40d81 100644
--- a/src/util/vircommand.c
+++ b/src/util/vircommand.c
@@ -782,6 +782,9 @@ virExec(virCommand *cmd)
         }
 
         if (pid > 0) {
+            /* close pipe[1], then the pipe can be closed if grandchild
+             * died prematurely */
+            VIR_FORCE_CLOSE(pipesync[1]);
             /* The parent expect us to have written the pid file before
              * exiting. Wait here for the child to write it and signal us. */
             if (cmd->pidfile &&
-- 
2.27.0