[PATCH v3 3/3] dpkg+linux: use Isar's lock via do_prepare[lockfiles] instead of flock

[Cedric Hombourger <Cedric_Hombourger@mentor.com>]

reprepro and apt operations may not run in parallel since this could result
in the apt database being updated (by reprepro) while it is being read (by
apt-get update). reprepro calls were already serialized with Isar's lock (via
do_deploy_deb[lockfiles]). Use the same lock for do_prepare in the dpkg and
linux-custom packaging code. This allows us to drop the /dpkg.lock flock and
use bitbake's locking scheme instead.

Signed-off-by: Cedric Hombourger <Cedric_Hombourger@mentor.com>
---
 meta/classes/dpkg.bbclass                       |  3 +++
 meta/recipes-devtools/buildchroot/files/deps.sh | 29 ++++++++++---------------
 meta/recipes-kernel/linux/linux-custom.inc      |  6 +++--
 3 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/meta/classes/dpkg.bbclass b/meta/classes/dpkg.bbclass
index e8bd6ba..2e53c1b 100644
--- a/meta/classes/dpkg.bbclass
+++ b/meta/classes/dpkg.bbclass
@@ -9,6 +9,9 @@ dpkg_prepare() {
     sudo -E chroot ${BUILDCHROOT_DIR} /isar/deps.sh ${PP}/${PPS} ${DISTRO_ARCH}
 }
 
+# apt and reprepro may not run in parallel, acquire the Isar lock
+do_prepare[lockfiles] += "${DEPLOY_DIR_APT}/isar.lock"
+
 # Build package from sources using build script
 dpkg_runbuild() {
     E="${@ bb.utils.export_proxies(d)}"
diff --git a/meta/recipes-devtools/buildchroot/files/deps.sh b/meta/recipes-devtools/buildchroot/files/deps.sh
index 854a4d5..4bd604f 100644
--- a/meta/recipes-devtools/buildchroot/files/deps.sh
+++ b/meta/recipes-devtools/buildchroot/files/deps.sh
@@ -12,21 +12,16 @@ source /isar/common.sh
 #   2) we add -y to go non-interactive
 install_cmd="apt-get -o Debug::pkgProblemResolver=yes --no-install-recommends -y"
 
-(
-    # Lock-protected because apt and dpkg do not wait in case of contention
-    flock 42 || exit 1
+# Make sure that we have latest isar-apt content.
+# Options meaning:
+#   Dir::Etc::sourcelist - specifies which source to be used
+#   Dir::Etc::sourceparts - disables looking for the other sources
+#   APT::Get::List-Cleanup - do not erase obsolete packages list for
+#                            upstream in '/var/lib/apt/lists'
+apt-get update \
+    -o Dir::Etc::sourcelist="sources.list.d/isar-apt.list" \
+    -o Dir::Etc::sourceparts="-" \
+    -o APT::Get::List-Cleanup="0"
 
-    # Make sure that we have latest isar-apt content.
-    # Options meaning:
-    #   Dir::Etc::sourcelist - specifies which source to be used
-    #   Dir::Etc::sourceparts - disables looking for the other sources
-    #   APT::Get::List-Cleanup - do not erase obsolete packages list for
-    #                            upstream in '/var/lib/apt/lists'
-    apt-get update \
-        -o Dir::Etc::sourcelist="sources.list.d/isar-apt.list" \
-        -o Dir::Etc::sourceparts="-" \
-        -o APT::Get::List-Cleanup="0"
-
-    # Install all build deps
-    mk-build-deps $set_arch -t "${install_cmd}" -i -r debian/control
-) 42>/dpkg.lock
+# Install all build deps
+mk-build-deps $set_arch -t "${install_cmd}" -i -r debian/control
diff --git a/meta/recipes-kernel/linux/linux-custom.inc b/meta/recipes-kernel/linux/linux-custom.inc
index 26c6ad8..8438143 100644
--- a/meta/recipes-kernel/linux/linux-custom.inc
+++ b/meta/recipes-kernel/linux/linux-custom.inc
@@ -29,13 +29,15 @@ KERNEL_DEBIAN_DEPENDS ?= "initramfs-tools | linux-initramfs-tool, kmod, linux-ba
 KERNEL_HEADERS_DEBIAN_DEPENDS ?= "libc6, libssl1.1"
 
 dpkg_prepare() {
-	# Lock-protected because apt and dpkg do not wait in case of contention
 	sudo -E chroot ${BUILDCHROOT_DIR} \
-		flock /dpkg.lock apt-get install \
+		apt-get install \
 			-y -o Debug::pkgProblemResolver=yes \
 			--no-install-recommends ${KBUILD_DEPENDS}
 }
 
+# apt and reprepro may not run in parallel, acquire the Isar lock
+do_prepare[lockfiles] += "${DEPLOY_DIR_APT}/isar.lock"
+
 dpkg_runbuild() {
 	# Install package builder script
 	sudo install -m 755 ${WORKDIR}/build-kernel.sh ${BUILDCHROOT_DIR}
-- 
2.11.0