1 files changed, 45 insertions, 0 deletions
diff --git a/autolock.sh b/autolock.sh
new file mode 100755
index 0000000000..88e27332e6
--- /dev/null
+++ b/autolock.sh
@@ -0,0 +1,45 @@
+#! /bin/sh
+# interlock - wrap program invocation in lock to allow
+#             parallel builds to work.
+# Written by Tom Tromey <tromey@cygnus.com>, Aug 10 1996
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+# Usage:
+#   interlock lock-dir-name program args-to-program...
+
+dirname="$1"
+program="$2"
+
+shift
+shift
+
+while (mkdir $dirname > /dev/null 2>&1 && exit 1 || exit 0); do
+   # Wait a bit.
+   sleep 1
+done
+
+# Race condition here: if interrupted after the loop but before this
+# trap, the lock can be left around.
+trap "rmdir $dirname > /dev/null 2>&1" 1 2 3 15
+
+# We have the lock, so run the program.
+$program ${1+"$@"}
+ret=$?
+
+# Release the lock.
+rmdir $dirname > /dev/null 2>&1
+
+exit $ret