From bfe9f06f9b1b9296feb46f4a6d64d1da8ce2a1f4 Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@ipxe.org>
Date: Tue, 26 Aug 2014 15:05:48 +0100
Subject: [PATCH] [build] Avoid deleting config header files if build is
 interrupted

With extremely unlucky timing, it is possible to interrupt a build and
cause make to delete config/named.h (and possibly any local
configuration headers).

Mark config/named.h and all local configuration headers as .PRECIOUS
to prevent make from ever deleting them.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---
 src/Makefile.housekeeping | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/Makefile.housekeeping b/src/Makefile.housekeeping
index 0e490f61..b2c69594 100644
--- a/src/Makefile.housekeeping
+++ b/src/Makefile.housekeeping
@@ -717,6 +717,8 @@ endif
 config/named.h : $(CONFIG_LIST)
 	$(Q)$(TOUCH) $@
 
+.PRECIOUS : config/named.h
+
 # These files use .incbin inline assembly to include a binary file.
 # Unfortunately ccache does not detect this dependency and caches
 # builds even when the binary file has changed.
@@ -1289,14 +1291,25 @@ CLEANUP += $(EINFO)
 # Local configs
 #
 CONFIG_HEADERS := $(patsubst config/%,%,$(wildcard config/*.h))
+CONFIG_LOCAL_HEADERS := $(foreach HEADER,$(CONFIG_HEADERS),\
+				  config/local/$(HEADER))
 
-$(foreach HEADER,$(CONFIG_HEADERS),config/local/$(HEADER)) :
+$(CONFIG_LOCAL_HEADERS) :
 	$(Q)$(TOUCH) $@
 
+.PRECIOUS : $(CONFIG_LOCAL_HEADERS)
+
 ifneq ($(CONFIG),)
-$(foreach HEADER,$(CONFIG_HEADERS),config/local/$(CONFIG)/$(HEADER)) :
+
+CONFIG_LOCAL_NAMED_HEADERS := $(foreach HEADER,$(CONFIG_HEADERS),\
+					config/local/$(CONFIG)/$(HEADER))
+
+$(CONFIG_LOCAL_NAMED_HEADERS) :
 	$(Q)$(MKDIR) -p $(dir $@)
 	$(Q)$(TOUCH) $@
+
+.PRECIOUS : $(CONFIG_LOCAL_NAMED_HEADERS)
+
 endif
 
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