and dolock

infrastructure/bin/dolock

@@ -0,0 +1,51 @@
+#! /usr/bin/perl
+# $OpenBSD: dolock,v 1.1 2010/08/20 14:40:31 espie Exp $
+# Copyright (c) 2004 Marc Espie <espie@openbsd.org>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+use strict;
+use warnings;
+use Fcntl;
+use File::Basename;
+
+if (@ARGV == 0) {
+	exit(1);
+}
+my $fname = shift;
+my $dname = dirname $fname;
+my $done = 0;
+
+unless (-e $dname) {
+	require File::Path;
+	File::Path::mkpath($dname);
+}
+if (!-d $dname) {
+	print STDERR "lock directory location $dname is not a directory\n";
+	exit(1);
+}
+
+while(1) {
+	if (sysopen my $handle, $fname, O_WRONLY | O_EXCL | O_CREAT, 0666) {
+		if (@ARGV)  {
+			print $handle join("\n", @ARGV), "\n";
+		}
+		close($handle);
+		exit(0);
+	}
+	unless ($done) {
+		print STDERR "Awaiting lock $fname\n";
+		$done = 1;
+	}
+	sleep(1);
+}