create a lock file during builds

prevent duplicate main instances of the build
system from running

the lock file is deleted when the parent process
exits, alongside the tmpdir deletion

the build system must only ever be run ot one
instance at a time, per work directory

Signed-off-by: Leah Rowe <leah@libreboot.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/build b/build
index 74ea1de6..bfd865c2 100755
--- a/build
+++ b/build
@@ -124,7 +124,8 @@ fetch_trees()
 
 fail()
 {
-	tmp_cleanup || printf "WARNING: can't rm tmpdir: %s\n" "$tmpdir" 1>&2
+	tmp_cleanup || printf "WARNING: can't rm tmp files: %s\n" "$tmpdir" \
+	    1>&2
 	err_ "${1}"
 }
 
@@ -132,6 +133,7 @@ tmp_cleanup()
 {
 	[ "$tmpdir_was_set" = "n" ] || return 0
 	rm -Rf "$tmpdir" || return 1
+	rm -f lock || return 1
 }
 
 main $@