run with timeout: return if timeout happened in list context

This can be relevant info do differentiate if an undef return value
happened due to the closure returning it or if it happened due to a
timeout.

While for quite a few cases this could be handled by a
variable captured by the passed closure code reference, acting as
messenger, that might often require needless wrapping.

Also run_fork_with_timeout warned errors of execution, but any such
error handling for an actual timeout is better handled at the call
site, as a context-less "got timeout" at STDERR or journal is really
not helpful.

I checked all call sites of both, run_fork_with_timeout and
run_with_timeout most do not use the result at all, and the ones that
do are in scalar context.

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

diff --git a/src/PVE/Tools.pm b/src/PVE/Tools.pm
index 2d728f8fc73739942020290d2db3f475d7c9c148..9ffac12100f0bec79be13d1052d5b04d8aa43134 100644 (file)
--- a/src/PVE/Tools.pm
+++ b/src/PVE/Tools.pm
@@ -118,11 +118,12 @@ sub run_with_timeout {
     my $prev_alarm = alarm 0; # suspend outer alarm early
 
     my $sigcount = 0;
+    my $got_timeout = 0;
 
     my $res;
 
     eval {
-       local $SIG{ALRM} = sub { $sigcount++; die "got timeout\n"; };
+       local $SIG{ALRM} = sub { $sigcount++; $got_timeout = 1;  die "got timeout\n"; };
        local $SIG{PIPE} = sub { $sigcount++; die "broken pipe\n" };
        local $SIG{__DIE__};   # see SA bug 4631
 
@@ -142,9 +143,9 @@ sub run_with_timeout {
     # this shouldn't happen anymore?
     die "unknown error" if $sigcount && !$err; # seems to happen sometimes
 
-    die $err if $err;
+    die $err if $err && !wantarray; # assume that user handles timeout err if called in list context
 
-    return $res;
+    return wantarray ? ($res, $got_timeout) : $res;
 }
 
 # flock: we use one file handle per process, so lock file
@@ -1015,9 +1016,10 @@ sub run_fork_with_timeout {
        $res = $child_res->{result};
        $error = $child_res->{error};
     };
+    my $got_timeout = 0;
     eval {
        if (defined($timeout)) {
-           run_with_timeout($timeout, $readvalues);
+           (undef, $got_timeout) = run_with_timeout($timeout, $readvalues);
        } else {
            $readvalues->();
        }
@@ -1032,7 +1034,7 @@ sub run_fork_with_timeout {
     die "interrupted by unexpected signal\n" if $sig_received;
 
     die $error if $error;
-    return $res;
+    return wantarray ? ($res, $got_timeout) : $res;
 }
 
 sub run_fork {