UBUNTU: debian: add locking to protect debian/files from parallel update

When building with high parallelism we may overlap calls to dh_gencontrol
and/or the .ddeb removal code from the debian/files list.  If these happen
in parallel files may be lost or updates fail leading to build failures or
incomplete packing lists.  Add primative locking to each of these scenarios
using the flock command, utilising a lock file in the debian directory.

Signed-off-by: Andy Whitcroft <apw@canonical.com>

5 files changed, 25 insertions, 17 deletions

diff --git a/debian.master/control.stub.in b/debian.master/control.stub.in
index ad433e22493..84dd89b05f9 100644
--- a/debian.master/control.stub.in
+++ b/debian.master/control.stub.in
@@ -3,7 +3,7 @@ Section: devel
 Priority: optional
 Maintainer: Ubuntu Kernel Team <kernel-team@lists.ubuntu.com>
 Standards-Version: 3.8.4.0
-Build-Depends: debhelper (>= 5), cpio, module-init-tools, kernel-wedge (>= 2.24ubuntu1), makedumpfile [amd64 i386], device-tree-compiler [powerpc], libelf-dev, binutils-dev, rsync, libdw-dev, dpkg (>= 1.16.0~ubuntu4)
+Build-Depends: debhelper (>= 5), cpio, module-init-tools, kernel-wedge (>= 2.24ubuntu1), makedumpfile [amd64 i386], device-tree-compiler [powerpc], libelf-dev, binutils-dev, rsync, libdw-dev, dpkg (>= 1.16.0~ubuntu4), util-linux
 Build-Depends-Indep: xmlto, docbook-utils, ghostscript, transfig, bzip2, sharutils, asciidoc
 Build-Conflicts: findutils (= 4.4.1-1ubuntu1)
 Vcs-Git: http://kernel.ubuntu.com/git-repos/ubuntu/ubuntu-precise.git
diff --git a/debian/rules.d/0-common-vars.mk b/debian/rules.d/0-common-vars.mk
index 8915c40826e..9022d53fad2 100644
--- a/debian/rules.d/0-common-vars.mk
+++ b/debian/rules.d/0-common-vars.mk
@@ -220,3 +220,8 @@ ifneq ($(LOCAL_ENV_CC),)
 kmake += CC=$(LOCAL_ENV_CC) DISTCC_HOSTS=$(LOCAL_ENV_DISTCC_HOSTS)
 endif
 
+# Locking is required in parallel builds to prevent loss of contents
+# of the debian/files.
+lockme_file = $(CURDIR)/debian/.LOCK
+lockme_cmd = flock -w 60
+lockme = $(lockme_cmd) $(lockme_file)
diff --git a/debian/rules.d/2-binary-arch.mk b/debian/rules.d/2-binary-arch.mk
index 7a42734e6c7..dec5adcf84f 100644
--- a/debian/rules.d/2-binary-arch.mk
+++ b/debian/rules.d/2-binary-arch.mk
@@ -268,7 +268,7 @@ endif
 	dh_compress -plinux-libc-dev
 	dh_fixperms -plinux-libc-dev
 	dh_installdeb -plinux-libc-dev
-	dh_gencontrol -plinux-libc-dev -- $(libc_dev_version)
+	$(lockme) dh_gencontrol -plinux-libc-dev -- $(libc_dev_version)
 	dh_md5sums -plinux-libc-dev
 	dh_builddeb -plinux-libc-dev
 endif
@@ -289,7 +289,7 @@ binary-%: install-%
 	dh_fixperms -p$(pkgimg) -X/boot/
 	dh_installdeb -p$(pkgimg)
 	dh_shlibdeps -p$(pkgimg)
-	dh_gencontrol -p$(pkgimg)
+	$(lockme) dh_gencontrol -p$(pkgimg)
 	dh_md5sums -p$(pkgimg)
 	dh_builddeb -p$(pkgimg) -- -Zbzip2 -z9
 
@@ -300,7 +300,7 @@ binary-%: install-%
 		dh_fixperms -p$(pkgimg_ex) -X/boot/; \
 		dh_installdeb -p$(pkgimg_ex); \
 		dh_shlibdeps -p$(pkgimg_ex); \
-		dh_gencontrol -p$(pkgimg_ex); \
+		$(lockme) dh_gencontrol -p$(pkgimg_ex); \
 		dh_md5sums -p$(pkgimg_ex); \
 		dh_builddeb -p$(pkgimg_ex) -- -Zbzip2 -z9; \
 	fi
@@ -311,7 +311,7 @@ binary-%: install-%
 	dh_fixperms -p$(pkghdr)
 	dh_shlibdeps -p$(pkghdr)
 	dh_installdeb -p$(pkghdr)
-	dh_gencontrol -p$(pkghdr)
+	$(lockme) dh_gencontrol -p$(pkghdr)
 	dh_md5sums -p$(pkghdr)
 	dh_builddeb -p$(pkghdr)
 
@@ -324,7 +324,7 @@ ifneq ($(skipsub),true)
 		dh_fixperms -p$$pkg -X/boot/;		\
 		dh_shlibdeps -p$$pkg;			\
 		dh_installdeb -p$$pkg;			\
-		dh_gencontrol -p$$pkg;			\
+		$(lockme) dh_gencontrol -p$$pkg;			\
 		dh_md5sums -p$$pkg;			\
 		dh_builddeb -p$$pkg;			\
 	done
@@ -336,7 +336,7 @@ ifneq ($(skipdbg),true)
 	dh_compress -p$(dbgpkg)
 	dh_fixperms -p$(dbgpkg)
 	dh_installdeb -p$(dbgpkg)
-	dh_gencontrol -p$(dbgpkg)
+	$(lockme) dh_gencontrol -p$(dbgpkg)
 	dh_md5sums -p$(dbgpkg)
 	dh_builddeb -p$(dbgpkg)
 
@@ -349,12 +349,15 @@ ifneq ($(skipdbg),true)
 	mv ../$(dbgpkg)_$(release)-$(revision)_$(arch).deb \
 		../$(dbgpkg)_$(release)-$(revision)_$(arch).ddeb
 	set -e; \
-	if grep -qs '^Build-Debug-Symbols: yes$$' /CurrentlyBuilding; then \
-		sed -i '/^$(dbgpkg)_/s/\.deb /.ddeb /' debian/files; \
-	else \
-		grep -v '^$(dbgpkg)_.*$$' debian/files > debian/files.new; \
-		mv debian/files.new debian/files; \
-	fi
+	( \
+		$(lockme_cmd) 9 || exit 1; \
+		if grep -qs '^Build-Debug-Symbols: yes$$' /CurrentlyBuilding; then \
+			sed -i '/^$(dbgpkg)_/s/\.deb /.ddeb /' debian/files; \
+		else \
+			grep -v '^$(dbgpkg)_.*$$' debian/files > debian/files.new; \
+			mv debian/files.new debian/files; \
+		fi; \
+	) 9>$(lockme_file)
 	# Now, the package wont get into the archive, but it will get put
 	# into the debug system.
 endif
@@ -415,7 +418,7 @@ ifeq ($(do_tools),true)
 	dh_fixperms -p$(toolspkg)
 	dh_shlibdeps -p$(toolspkg)
 	dh_installdeb -p$(toolspkg)
-	dh_gencontrol -p$(toolspkg)
+	$(lockme) dh_gencontrol -p$(toolspkg)
 	dh_md5sums -p$(toolspkg)
 	dh_builddeb -p$(toolspkg)
 endif
diff --git a/debian/rules.d/3-binary-indep.mk b/debian/rules.d/3-binary-indep.mk
index 55c7904b543..462d7219cd2 100644
--- a/debian/rules.d/3-binary-indep.mk
+++ b/debian/rules.d/3-binary-indep.mk
@@ -125,7 +125,7 @@ binary-headers: install-headers
 	dh_compress -p$(indep_hdrpkg)
 	dh_fixperms -p$(indep_hdrpkg)
 	dh_installdeb -p$(indep_hdrpkg)
-	dh_gencontrol -p$(indep_hdrpkg)
+	$(lockme) dh_gencontrol -p$(indep_hdrpkg)
 	dh_md5sums -p$(indep_hdrpkg)
 	dh_builddeb -p$(indep_hdrpkg)
 
@@ -138,6 +138,6 @@ binary-indep: install-indep
 	dh_compress -i
 	dh_fixperms -i
 	dh_installdeb -i
-	dh_gencontrol -i
+	$(lockme) dh_gencontrol -i
 	dh_md5sums -i
 	dh_builddeb -i
diff --git a/debian/rules.d/5-udebs.mk b/debian/rules.d/5-udebs.mk
index 63583deb5b0..2cb81fdd6ef 100644
--- a/debian/rules.d/5-udebs.mk
+++ b/debian/rules.d/5-udebs.mk
@@ -33,6 +33,6 @@ do-binary-udebs: debian/control
 	[ -z "$dilist" ] || \
 	for i in $$dilist; do \
 	  dh_fixperms -p$$i; \
-	  dh_gencontrol -p$$i; \
+	  $(lockme) dh_gencontrol -p$$i; \
 	  dh_builddeb -p$$i; \
 	done