From 83d5f55b09150818b31c611df48a177cd384ca7d Mon Sep 17 00:00:00 2001
From: Scott Walters <scott@slowass.net>
Date: Wed, 19 May 2010 07:52:43 -0400
Subject: [PATCH] PID files contain the PID so that on next run, we can test to
 see if that PID is still alive.  If it isn't, the daemon was kill -9'd, the
 system crashed, or similar.  It isn't running any more and it's safe to start
 up again.  Don't die on startup unless the PID in the PID file is valid.

---
 sbin/spectre.pl | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/sbin/spectre.pl b/sbin/spectre.pl
index 309467008..141eff668 100755
--- a/sbin/spectre.pl
+++ b/sbin/spectre.pl
@@ -114,8 +114,20 @@ elsif ($daemon) {
         die "Spectre is already running.\n";
     }
     elsif (-e $pidFileName){
-        die "pidFile $pidFileName already exists\n";
+        # oh, ffs ... die "pidFile $pidFileName already exists\n";
+        open my $pidFile, '<', $pidFileName or die "$pidFileName: $!";
+        (my $pid) = readline $pidFile;
+        chomp $pid;
+        if(defined $pid and $pid =~ m/^(\d+)$/) {
+            if(kill 0, $1) {
+                die "$0: already running as PID $1";
+            } else { 
+                warn "pidfile contains $pid but that process seems to have terminated" 
+            }
+        }
+        close $pidFile;
     }
+    # XXXX warn if we can't open the log file before forking or else make it not fatal or else close STDOUT/STDERR afterwards; don't fail silently -- sdw
     #fork and exit(sleep(1) and print((ping())?"Spectre failed to start!\n":"Spectre started successfully!\n"));  #Can't have right now.
     require POSIX;
     fork and exit;