[PATCH pve-common 1/1] RESTEnvironment: periodically reap workers as SIGCHLD fallback

[Hannes Laimer <h.laimer@proxmox.com>]

Libraries may temporarily override $SIG{CHLD}, causing worker exit
signals to be lost. Poll worker_reaper every 5 seconds via an AnyEvent
timer to catch any missed signals in API server contexts where this can
be problematic.

Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>
---
 src/PVE/RESTEnvironment.pm | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/PVE/RESTEnvironment.pm b/src/PVE/RESTEnvironment.pm
index 81d7e29..cb44823 100644
--- a/src/PVE/RESTEnvironment.pm
+++ b/src/PVE/RESTEnvironment.pm
@@ -37,6 +37,7 @@ my $rest_env;
 
 my $WORKER_PIDS;
 my $WORKER_FLAG = 0;
+my $worker_reaper_timer;
 
 my $log_task_result = sub {
     my ($upid, $user, $status) = @_;
@@ -124,6 +125,14 @@ sub init {
         }
     };
 
+    # Periodically reap workers as a fallback in case a library call temporarily overrides
+    # $SIG{CHLD} and causes us to miss a signal. Only useful when an event loop is running.
+    $worker_reaper_timer = AnyEvent->timer(
+        after => 5,
+        interval => 5,
+        cb => sub { $worker_reaper->() },
+    );
+
     # environment types
     # cli  ... command started fron command line
     # pub  ... access from public server (pveproxy)
-- 
2.47.3