Employ Stupid Shell Tricks to get exit status out of pipeline command.

os/create-image

 #!/usr/bin/perl -wT
 
 #
-# Copyright (c) 2000-2012 University of Utah and the Flux Group.
+# Copyright (c) 2000-2014 University of Utah and the Flux Group.
 # 
 # {{{EMULAB-LICENSE
 # 
@@ -50,18 +50,23 @@ delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};
 #
 # No configure vars.
 #
-my $sudo;
+my $sudo = "";
 my $zipper = "/usr/local/bin/imagezip";
 my $uploader = "/usr/local/bin/frisupload";
 my $slice  = "";
 my $device;
 my $filename;
 
-for my $path (qw#/usr/local/bin /usr/bin#) {
+#
+# If we are running as a user, then we will need sudo
+#
+if ($EUID != 0) {
+    for my $path (qw#/usr/local/bin /usr/bin#) {
 	if (-e "$path/sudo") {
-		$sudo = "$path/sudo";
-		last;
+	    $sudo = "$path/sudo";
+	    last;
 	}
+    }
 }
 
 # Frisbee master server params
@@ -168,8 +173,11 @@ if ($^O eq 'linux') {
 #
 # If imageid is defined, we use the frisbee uploader.
 #
-my $cmd = "$zipper $slice $device $filename";
+my $cmd = "$sudo $zipper $slice $device $filename";
 if (defined($imageid)) {
+    # use basic shell sleezy trick to capture exit status from imagezip
+    $cmd = "( $cmd || echo \$? > /tmp/imagezip.stat )";
+
     $cmd .= " | $uploader -S $iserver -F $imageid -";
 }
 
@@ -178,9 +186,20 @@ if (defined($imageid)) {
 # with proper trust should be able to zip up a disk. sudo will fail
 # if the user is not in the proper group.
 #
-if (system("$sudo $cmd")) {
+if (system("$cmd") || -e "/tmp/imagezip.stat") {
+    my $stat = sprintf("0x%04x", $?);
+    my $izstat = 0;
+    if (-e "/tmp/imagezip.stat") {
+	$izstat = `cat /tmp/imagezip.stat`;
+	chomp($izstat);
+    }
+    $izstat = sprintf("0x%04x", $izstat);
+
     print STDERR "*** Failed to create image!\n";
-    print STDERR "    command: '$sudo $cmd'\n";
+    print STDERR "    command:   '$cmd'\n";
+    print STDERR "    status:    $stat\n";
+    print STDERR "    izstatus:  $izstat\n"
+	if ($izstat);
     exit 1;
 }