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- #! /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
-