From 4af18f43633a19ceb38848901306dcf5f46074d5 Mon Sep 17 00:00:00 2001
From: mb <mb@3c298f89-4303-0410-b956-a3cf2f4a3e73>
Date: Fri, 29 Oct 2010 14:53:16 +0000
Subject: [PATCH] Add macro for locking of recipe commands.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@23708 3c298f89-4303-0410-b956-a3cf2f4a3e73
---
 rules.mk | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/rules.mk b/rules.mk
index 23445bfae..007e5bc9b 100644
--- a/rules.mk
+++ b/rules.mk
@@ -249,6 +249,16 @@ define include_mk
 $(eval -include $(if $(DUMP),,$(STAGING_DIR)/mk/$(strip $(1))))
 endef
 
+# Execute commands under flock
+# $(1) => The shell expression.
+# $(2) => The lock name. If not given, the global lock will be used.
+# $(3) => The filedescriptor used for the lock. Defaults to 1023.
+define locked
+    ( $(STAGING_DIR_HOST)/bin/flock -x $(if $(3),$(3),1023) && \
+      $(1) \
+    ) $(if $(3),$(strip $(3)),1023)>$(TMP_DIR)/.$(if $(2),$(strip $(2)),global).flock
+endef
+
 # file extension
 ext=$(word $(words $(subst ., ,$(1))),$(subst ., ,$(1)))
 
-- 
2.20.1