From c7eee68431f24ee3071150217fe12c00f895ce2b Mon Sep 17 00:00:00 2001
Message-Id: <c7eee68431f24ee3071150217fe12c00f895ce2b.1718475343.git.mdw@distorted.org.uk>
From: Mark Wooding <mdw@chiark.greenend.org.uk>
Date: Tue, 2 Jun 2020 11:09:36 +0100
Subject: [PATCH] bin/disorder-notify: Improve error handling in the `select'
 loop.
Organization: Straylight/Edgeware

From: Mark Wooding <mdw@distorted.org.uk>

Don't crash out on read errors.  Report the problem in the `lost
connection' message.
---
 bin/disorder-notify | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/bin/disorder-notify b/bin/disorder-notify
index 3c57073..b632ef4 100755
--- a/bin/disorder-notify
+++ b/bin/disorder-notify
@@ -191,6 +191,7 @@ sub watch_and_notify0 ($) {
   my $buffer = "";
   my @lines = ();
   my $rdin = ""; vec($rdin, (fileno $sk_log), 1) = 1;
+  my $loss;
 
   WATCH: for (;;) {
     for my $line (@lines) {
@@ -218,13 +219,13 @@ sub watch_and_notify0 ($) {
       }
     }
 
-    last WATCH unless $sk_log;
+    if (!$sk_log) { $loss = "EOF from server"; last WATCH; }
     select my $rdout = $rdin, undef, undef, undef;
     READ: for (;;) {
       my ($b, $n);
       eval { $n = sysread $sk_log, $b, 4096; };
       if ($@ && $@->errno == EAGAIN) { last READ; }
-      elsif ($@) { die $@; }
+      elsif ($@) { $loss = "error from read: " . $@->errno; last WATCH; }
       elsif (!$n) { close $sk_log; $sk_log = undef; }
       else { $buffer .= $b; }
     }
@@ -233,7 +234,7 @@ sub watch_and_notify0 ($) {
     $buffer = pop @lines;
   }
 
-  notify "$TITLE state", "Lost connection";
+  notify "$TITLE state", "Lost connection: $loss";
 
   close $sk;
   close $sk_log if defined $sk_log;
-- 
[mdw]