From 5e359c5927e8df1a0ce1652a4b83436e9d5d3410 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 10 Aug 2014 20:38:41 +0100
Subject: [PATCH] Better reporting of child exit statuses (esp. deaths due to
 signals).

---
 debian/changelog |  1 +
 dgit             | 22 +++++++++++++++++++---
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/debian/changelog b/debian/changelog
index 978ad109..f70f2ff6 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -37,6 +37,7 @@ dgit (0.22~experimental1) experimental; urgency=low
   * Improve error message for .dsc having already been signed (iff
     using libdpkg-perl 1.17.x).  Closes:#731635.
   * Improve error message for .dsc parsing failures more generally.
+  * Better reporting of child exit statuses (esp. deaths due to signals).
 
   Major new feature, currently stalled awaiting server infrastructure:
   * dgit-repos-server: New program for receiving signed-tag-based
diff --git a/dgit b/dgit
index b2426467..e3fc0eef 100755
--- a/dgit
+++ b/dgit
@@ -30,6 +30,7 @@ use Dpkg::Version;
 use POSIX;
 use IPC::Open2;
 use Digest::SHA;
+use Config;
 
 our $our_version = 'UNRELEASED'; ###substituted###
 
@@ -133,6 +134,23 @@ END {
     }
 };
 
+our @signames = split / /, $Config{sig_name};
+
+sub waitstatusmsg () {
+    if (!$?) {
+	return "terminated, reporting successful completion";
+    } elsif (!($? & 255)) {
+	return "failed with error exit status ".WEXITSTATUS($?);
+    } elsif (WIFSIGNALED($?)) {
+	my $signum=WTERMSIG($?);
+	return "died due to fatal signal ".
+	    ($signames[$signum] // "number $signum").
+	    ($? & 128 ? " (core dumped)" : ""); # POSIX(3pm) has no WCOREDUMP
+    } else {
+	return "failed with unknown wait status ".$?;
+    }
+}
+
 sub printdebug { print DEBUG $debugprefix, @_ or die $!; }
 
 sub fail { 
@@ -350,10 +368,8 @@ sub failedcmd {
     { local ($!); printcmd \*STDERR, "$us: failed command:", @_ or die $!; };
     if ($!) {
 	fail "failed to fork/exec: $!";
-    } elsif (!($? & 0xff)) {
-	fail "subprocess failed with error exit status ".($?>>8);
     } elsif ($?) {
-	fail "subprocess crashed (wait status $?)";
+	fail "subprocess ".waitstatusmsg();
     } else {
 	fail "subprocess produced invalid output";
     }
-- 
2.30.2