From bd7891126edbe8500e813f10a78082b27156faef Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Wed, 25 Jan 2012 21:46:58 +0000
Subject: [PATCH] processpcfgz: completely revamped subprocess data structures
 and error handling

---
 update-xfonts-traditional | 66 +++++++++++++++++++++++++++++----------
 1 file changed, 50 insertions(+), 16 deletions(-)

diff --git a/update-xfonts-traditional b/update-xfonts-traditional
index 8791e22..2e8c0d7 100755
--- a/update-xfonts-traditional
+++ b/update-xfonts-traditional
@@ -176,6 +176,7 @@ sub processpcfgz ($$$$) {
     my ($usread,$uswrite);
     my ($reader,$writer);
     my @children;
+    my %ch;
     foreach my $proc (['gunzip'], ['pcf2bdf'], [],
 		      ['bdftopcf'],['',qw(gzip -1 -n)]) {
 	my $isfinal = (@$proc && $proc->[0] eq '');
@@ -201,7 +202,14 @@ sub processpcfgz ($$$$) {
 		close $uswrite or die $! if $uswrite;
 		exec $exe @$proc or die "$exe $!";
 	    }
-	    push @children, [ $child, $exe, defined $usread ];
+	    my $ch = {
+		Pid => $child,
+		Exe => $exe,
+		Stage => (!$exe ? 'self' : defined $usread ? 'out' : 'in'),
+		SigOK => { },
+	    };
+	    push @children, $ch;
+	    $ch{$exe} = $ch;
 	    close $current or die $!;
 	    close $writer or die $!;
 	    $current = $reader;
@@ -213,25 +221,51 @@ sub processpcfgz ($$$$) {
     }
     my $r = processbdf($usread,$uswrite,$logfile,$what);
     my $none = $r !~ m/^\d/;
-    if ($none) {
+
+    $ch{'gunzip'}{SigOK}{13} = 1;
+    # ... we never care if pcf2bdf didn't want all the output from gunzip
+
+    if ($none || !$r) {
+	# We're not going to install or use this so we can kill our
+	# input and output filters.  We kill the input filters so that
+	# we don't risk waiting for them.  (If the input filter died
+	# for some other reason then sending it a KILL now won't
+	# affect its exit status.)  We kill the output filters (before
+	# we close the output pipe) so we don't produce messages from
+	# our output filters about corrupted data.
 	flush $uswrite or die $!;
-    } else {
-	close $uswrite or die $!;
+
+	foreach my $ch (@children) {
+	    if ($ch->{Stage} ne 'self') {
+		kill 9, $ch->{Pid} or die "$ch->{Pid} $ch->{Exe} $!";
+		$ch->{SigOK}{9} = 1;
+	    }
+	}
+	$ch{'pcf2bdf'}{SigOK}{13} = 1;
+	# ... we might not have read all the output from pcf2bdf, which is OK
     }
+    close $uswrite or die $!;
     close $usread or die $!;
-    foreach my $chinfo (@children) {
-	my ($child,$exe,$isoutput)=@$chinfo;
-	my $sigok = 0;
-	if ($none) {
-	    if ($isoutput) {
-		$sigok = 9;
-		kill 9, $child or die "$child $!";
-	    } else {
-		$sigok = 13;
-	    }
+
+    foreach my $ch (@children) {
+	$!=0; waitpid($ch->{Pid}, 0) == $ch->{Pid} or
+	    die "$ch->{Pid} $ch->{Exe} $!";
+	$ch->{St} = $?;
+    }
+
+    my $st_isok = sub {
+	my ($ch) = @_;
+	my $st = $ch->{St};
+	return !$st || $ch->{SigOK}{($st & ~128)};
+    };
+
+    foreach my $ch (@children) {
+	if (!$st_isok->($ch)) {
+	    die "update-xfonts-traditional:".
+		" $ch->{Exe} [$ch->{Pid}] for $inpcfgz".
+		" failed $ch->{St}".
+		" (".(join ' ', keys %{ $ch->{SigOK} })." ok)\n";
 	}
-	$!=0; waitpid($child, 0) == $child or die "$child $!";
-	!$? or ($?&~128)==$sigok or die "$exe [$child] $sigok $?";
     }
     return $r;
 }
-- 
2.30.2