From 4c2f66d8fb0992082ac6ed7343ace8f277e2ba70 Mon Sep 17 00:00:00 2001
From: dakkar <dakkar@thenautilus.net>
Date: Sat, 10 Apr 2021 12:42:29 +0100
Subject: cope with inhibitor dying
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

not great, since a different process may be running with that pid by
the time we check…
---
 xscreensaver-dbus | 50 ++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 44 insertions(+), 6 deletions(-)

diff --git a/xscreensaver-dbus b/xscreensaver-dbus
index f4dcfa2..002c0d9 100755
--- a/xscreensaver-dbus
+++ b/xscreensaver-dbus
@@ -90,12 +90,18 @@ package SaverImpl {
         return $self;
     }
 
+    our $_message;
+    sub _dispatch_object($self,$connection,$message,@etc) {
+        local $_message = $message;
+        return $self->SUPER::_dispatch_object($connection,$message,@etc);
+    }
+
     sub Inhibit($self,$name,$reason) {
-        return $self->{__inhibit_cb}->($name,$reason);
+        return $self->{__inhibit_cb}->($name,$reason,$_message);
     }
 
     sub UnInhibit($self,$cookie) {
-        return $self->{__uninhibit_cb}->($cookie);
+        return $self->{__uninhibit_cb}->($cookie,$_message);
     }
 };
 
@@ -104,9 +110,13 @@ package Saver {
     use experimental 'signatures';
     use curry;
     use Log::Any '$log';
+    use Try::Tiny;
 
     has reactor => ( is => 'ro', required => 1 );
     has bus => ( is => 'lazy', builder => sub { Net::DBus->session() } );
+    has dbus_srv => ( is => 'lazy', builder => sub { shift->bus->get_service('org.freedesktop.DBus') });
+    has dbus_obj => ( is => 'lazy', builder => sub { shift->dbus_srv->get_object('/org/freedesktop/DBus') });
+
     has service => (
         is => 'lazy',
         builder => sub {
@@ -149,12 +159,22 @@ package Saver {
         return;
     }
 
-    sub inhibit($self,$name,$reason) {
+    sub inhibit($self,$name,$reason,$message) {
+        my $sender_pid = try {
+            return $self->dbus_obj->GetConnectionUnixProcessID(
+                $message->get_sender,
+            );
+        } catch {
+            $log->warning('problems getting PID of inhibitor',{error=>$_});
+            return undef;
+        };
+
         my $cookie;
         do {
             $cookie = int(rand(2**31))
         } until !exists $self->_inhibits->{$cookie};
-        $self->_inhibits->{$cookie} = [ $name, $reason ];
+
+        $self->_inhibits->{$cookie} = [ $name, $reason, $sender_pid ];
 
         $log->debugf(
             '<%s> stops screensaver for <%s> (cookie %d) - %d active',
@@ -165,13 +185,14 @@ package Saver {
         return $cookie;
     }
 
-    sub uninhibit($self,$cookie) {
+    sub uninhibit($self,$cookie,$message) {
         my $inhibit = delete $self->_inhibits->{$cookie}
             or return;
+        my ($name, $reason, $sender_pid) = @$inhibit;
 
         $log->debugf(
             '<%s> resumed screensaver for <%s> (cookie %d) - %d left',
-            @$inhibit, $cookie, scalar(keys $self->_inhibits->%*),
+            $name, $reason, $cookie, scalar(keys $self->_inhibits->%*),
         );
 
         $self->reactor->toggle_timeout($self->_prod_id, 0)
@@ -181,6 +202,23 @@ package Saver {
     }
 
     sub prod_screensaver($self) {
+        for my $cookie (sort keys $self->_inhibits->%*) {
+            my ($name, $reason, $sender_pid) = @{$self->_inhibits->{$cookie}};
+            next if kill 0, $sender_pid;
+            # uh oh, caller is dead
+            my $inhibit = delete $self->_inhibits->{$cookie};
+
+            $log->debugf(
+                '<%s> is dead (it stopped screensaver for <%s>, cookie %d) - %d left',
+                $name, $reason, $cookie, scalar(keys $self->_inhibits->%*),
+            );
+        }
+
+        unless ($self->_inhibits->%*) {
+            $self->reactor->toggle_timeout($self->_prod_id, 0);
+            return;
+        }
+
         $log->debug('prodding xscreensaver');
         system(qw(xscreensaver-command -deactivate));
     }
-- 
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