[pve-devel] [PATCH v5 1/4] migrate: collect migration tunnel child process

[Thomas Lamprecht]

use waitpid with WNO_HANG to check if the ssh tunnel child process
is still running and collect at the same time if it exited.

Signed-off-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
---

changes since previous veriosn:
* adapt to dietmars suggestion, slightly adapted.
  changed name of the private local sub and logged if for some reason
  we could not collect the child after sigkill (just to be sure)

 PVE/QemuMigrate.pm | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/PVE/QemuMigrate.pm b/PVE/QemuMigrate.pm
index a25efff..954de3c 100644
--- a/PVE/QemuMigrate.pm
+++ b/PVE/QemuMigrate.pm
@@ -5,6 +5,7 @@ use warnings;
 use PVE::AbstractMigrate;
 use IO::File;
 use IPC::Open2;
+use POSIX qw( WNOHANG );
 use PVE::INotify;
 use PVE::Tools;
 use PVE::Cluster;
@@ -44,17 +45,28 @@ sub fork_command_pipe {
 sub finish_command_pipe {
     my ($self, $cmdpipe, $timeout) = @_;
 
+    my $cpid = $cmdpipe->{pid};
+    return if !defined($cpid);
+
     my $writer = $cmdpipe->{writer};
     my $reader = $cmdpipe->{reader};
 
     $writer->close();
     $reader->close();
 
-    my $cpid = $cmdpipe->{pid};
+    my $collect_child_process = sub {
+	my $res = waitpid($cpid, WNOHANG);
+	if (defined($res) && ($res == $cpid)) {
+	    delete $cmdpipe->{cpid};
+	    return 1;
+	} else {
+	    return 0;
+	}
+     };
 
     if ($timeout) {
 	for (my $i = 0; $i < $timeout; $i++) {
-	    return if !PVE::ProcFSTools::check_process_running($cpid);
+	    return if &$collect_child_process();
 	    sleep(1);
 	}
     }
@@ -64,13 +76,16 @@ sub finish_command_pipe {
 
     # wait again
     for (my $i = 0; $i < 10; $i++) {
-	return if !PVE::ProcFSTools::check_process_running($cpid);
+	return if &$collect_child_process();
 	sleep(1);
     }
 
     $self->log('info', "ssh tunnel still running - terminating now with SIGKILL\n");
     kill 9, $cpid;
     sleep 1;
+
+    $self->log('err', "ssh tunnel child process (PID $cpid) couldn't be collected\n")
+	if !&$collect_child_process();
 }
 
 sub fork_tunnel {
-- 
2.1.4