[PATCH v3 1/3] dpkg: move installation of dependencies into dpkg_prepare

[Cedric Hombourger <Cedric_Hombourger@mentor.com>]

In preparation for a rework of locking mechanisms around apt
operations (installation of packages or inclusion of new
packages into the isar-apt database), move the code for
installing build dependencies out of dpkg_runbuild and into
a new function: dpkg_prepare.

Signed-off-by: Cedric Hombourger <Cedric_Hombourger@mentor.com>
---
 doc/technical_overview.md                         | 29 ++++++++++----
 meta/classes/dpkg-base.bbclass                    | 30 +++++++++++---
 meta/classes/dpkg-raw.bbclass                     | 15 ++++---
 meta/classes/dpkg.bbclass                         |  8 +++-
 meta/recipes-devtools/buildchroot/buildchroot.inc |  9 ++++-
 meta/recipes-devtools/buildchroot/files/build.sh  | 48 +----------------------
 meta/recipes-devtools/buildchroot/files/common.sh | 28 +++++++++++++
 meta/recipes-devtools/buildchroot/files/deps.sh   | 32 +++++++++++++++
 meta/recipes-kernel/linux-module/module.inc       |  2 +-
 9 files changed, 128 insertions(+), 73 deletions(-)
 create mode 100644 meta/recipes-devtools/buildchroot/files/common.sh
 create mode 100644 meta/recipes-devtools/buildchroot/files/deps.sh

diff --git a/doc/technical_overview.md b/doc/technical_overview.md
index ddd2c79..4f6d954 100644
--- a/doc/technical_overview.md
+++ b/doc/technical_overview.md
@@ -217,24 +217,37 @@ Both consist of the following steps:
 3. Task `do_install` _only_ for `dpkg-raw`: copy all you want in your
    debian package to `${D}`, install hooks in `${D}/DEBIAN`
 
-4. Task `do_build`: mount folder with unpacked files to buildchroot, execute
-   the actual build function `dpkg_runbuild`, and finally umount again
+4. Task `do_prepare': perform any preparation steps to the unpacked/patched
+   sources before the build. This task calls the dpkg_prepare shell function
+   with the buildchroot mounts in place (`dpkg_do_mounts')
 
-   4.1. the `dpkg_runbuild` function of `dpkg.bbclass` runs `build.sh` in the
-        buildchroot. That performs the following:
+   4.1. the `dpkg_prepare` function of `dpkg.bbclass` runs `/isar/deps.sh` in
+        the buildchroot. That performs the following:
 
         1. Go to `/home/build/${PN}`
 
         2. Get list of dependencies from debian/control and install them
 
-        3. Run dpkg-buildpackage
+   4.2. the `dpkg_prepare` function of `dpkg-raw.bbclass` translate the
+        recipe meta-data into a debian/control file suitable for packaging
+        with dpkg-deb
+
+5. Task `do_build`: mount folder (`dpkg_do_mounts') with unpacked files to buildchroot,
+   execute the actual build function `dpkg_runbuild`, and finally umount again
+   (`dpkg_undo_mounts')
+
+   5.1. the `dpkg_runbuild` function of `dpkg.bbclass` runs `build.sh` in the
+        buildchroot. That performs the following:
+
+        1. Go to `/home/build/${PN}`
+
+        2. Run dpkg-buildpackage
 
-   4.2. the `dpkg_runbuild` function of `dpkg-raw.bbclass` basically runs
+   5.2. the `dpkg_runbuild` function of `dpkg-raw.bbclass` basically runs
         `dpkg-deb` to construct a Debian package from a folder of files,
 	without compiling anything
 
-
-5. Task `do_deploy_deb`: install successfully built packages
+6. Task `do_deploy_deb`: install successfully built packages
    `${WORKDIR}/*.deb` to deploy directory `${DEPLOY_DIR_DEB}`
 
 ## 3.6 Populate Target Filesystem
diff --git a/meta/classes/dpkg-base.bbclass b/meta/classes/dpkg-base.bbclass
index a41df2c..5826357 100644
--- a/meta/classes/dpkg-base.bbclass
+++ b/meta/classes/dpkg-base.bbclass
@@ -13,7 +13,7 @@ python __anonymous() {
         dep = "buildchroot-host:do_build"
         rootfs = d.getVar('BUILDCHROOT_HOST_DIR', True)
 
-    d.setVarFlag('do_build', 'depends', dep)
+    d.setVarFlag('do_prepare', 'depends', dep)
     d.setVar('BUILDCHROOT_DIR', rootfs)
 }
 
@@ -32,7 +32,7 @@ addtask patch after do_adjust_git before do_build
 
 # Add dependency between Isar recipes
 DEPENDS ?= ""
-do_build[deptask] = "do_deploy_deb"
+do_prepare[deptask] = "do_deploy_deb"
 
 def get_package_srcdir(d):
     s = d.getVar("S", True)
@@ -50,7 +50,10 @@ PPS ?= "${@get_package_srcdir(d)}"
 BUILDROOT = "${BUILDCHROOT_DIR}/${PP}"
 do_build[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
 
-# default to "emtpy" implementation
+# default to "emtpy" implementation for dpkg_prepare() and dpkg_runbuild()
+dpkg_prepare() {
+    true
+}
 dpkg_runbuild() {
     die "This should never be called, overwrite it in your derived class"
 }
@@ -58,7 +61,7 @@ dpkg_runbuild() {
 MOUNT_LOCKFILE = "${BUILDCHROOT_DIR}/mount.lock"
 
 # Wrap the function dpkg_runbuild with the bind mount for buildroot
-do_build() {
+dpkg_do_mounts() {
     mkdir -p ${BUILDROOT}
     sudo mount --bind ${WORKDIR} ${BUILDROOT}
 
@@ -70,13 +73,28 @@ do_build() {
             mount -t devtmpfs -o mode=0755,nosuid devtmpfs ${BUILDCHROOT_DIR}/dev
             mount -t proc none ${BUILDCHROOT_DIR}/proc
         fi'
+}
 
-    dpkg_runbuild
-
+dpkg_undo_mounts() {
     sudo umount ${BUILDROOT} 2>/dev/null || true
     sudo rmdir ${BUILDROOT} 2>/dev/null || true
 }
 
+do_prepare() {
+    dpkg_do_mounts
+    dpkg_prepare
+    dpkg_undo_mounts
+}
+
+addtask prepare after do_patch before do_build
+do_prepare[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
+
+do_build() {
+    dpkg_do_mounts
+    dpkg_runbuild
+    dpkg_undo_mounts
+}
+
 CLEANFUNCS += "repo_clean"
 
 repo_clean() {
diff --git a/meta/classes/dpkg-raw.bbclass b/meta/classes/dpkg-raw.bbclass
index 28233ac..c5f1c88 100644
--- a/meta/classes/dpkg-raw.bbclass
+++ b/meta/classes/dpkg-raw.bbclass
@@ -14,9 +14,9 @@ do_install() {
 }
 
 do_install[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
-addtask install after do_unpack before do_deb_package_prepare
+addtask install after do_unpack before do_prepare
 
-do_deb_package_prepare() {
+deb_package_prepare() {
 	sudo rm -rf ${D}/DEBIAN
 	mkdir -p ${D}/DEBIAN
 	cat<<-__EOF__ > ${D}/DEBIAN/control
@@ -42,17 +42,16 @@ do_deb_package_prepare() {
 	done
 }
 
-do_deb_package_prepare[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
-addtask deb_package_prepare after do_install before do_deb_package_conffiles
-
-do_deb_package_conffiles() {
+deb_package_conffiles() {
 	CONFFILES=${D}/DEBIAN/conffiles
 	find ${D} -type f -path '${D}/etc/*' | sed -e 's|^${D}|/|' >> $CONFFILES
 	test -s $CONFFILES || rm $CONFFILES
 }
 
-do_deb_package_conffiles[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
-addtask deb_package_conffiles after do_deb_package_prepare before do_build
+dpkg_prepare() {
+	deb_package_prepare
+	deb_package_conffiles
+}
 
 dpkg_runbuild() {
 	sudo chown -R root:root ${D}/DEBIAN/
diff --git a/meta/classes/dpkg.bbclass b/meta/classes/dpkg.bbclass
index ab70645..e8bd6ba 100644
--- a/meta/classes/dpkg.bbclass
+++ b/meta/classes/dpkg.bbclass
@@ -3,8 +3,14 @@
 
 inherit dpkg-base
 
+# Install build dependencies for package
+dpkg_prepare() {
+    E="${@ bb.utils.export_proxies(d)}"
+    sudo -E chroot ${BUILDCHROOT_DIR} /isar/deps.sh ${PP}/${PPS} ${DISTRO_ARCH}
+}
+
 # Build package from sources using build script
 dpkg_runbuild() {
     E="${@ bb.utils.export_proxies(d)}"
-    sudo -E chroot ${BUILDCHROOT_DIR} /build.sh ${PP}/${PPS} ${DISTRO_ARCH}
+    sudo -E chroot ${BUILDCHROOT_DIR} /isar/build.sh ${PP}/${PPS} ${DISTRO_ARCH}
 }
diff --git a/meta/recipes-devtools/buildchroot/buildchroot.inc b/meta/recipes-devtools/buildchroot/buildchroot.inc
index 43e3cd6..7dd909e 100644
--- a/meta/recipes-devtools/buildchroot/buildchroot.inc
+++ b/meta/recipes-devtools/buildchroot/buildchroot.inc
@@ -8,7 +8,9 @@ LIC_FILES_CHKSUM = "file://${LAYERDIR_isar}/licenses/COPYING.GPLv2;md5=751419260
 
 FILESPATH_prepend := "${THISDIR}/files:"
 SRC_URI = "file://configscript.sh \
-           file://build.sh"
+           file://build.sh \
+           file://common.sh \
+           file://deps.sh"
 PV = "1.0"
 
 inherit isar-bootstrap-helper
@@ -27,7 +29,10 @@ do_build() {
 
     # Install package builder script
     sudo chmod -R a+rw "${BUILDCHROOT_DIR}/home/builder"
-    sudo install -m 755 ${WORKDIR}/build.sh ${BUILDCHROOT_DIR}
+    sudo install -m 755 -d ${BUILDCHROOT_DIR}/isar
+    sudo install -m 755 ${WORKDIR}/build.sh ${BUILDCHROOT_DIR}/isar/
+    sudo install -m 755 ${WORKDIR}/common.sh ${BUILDCHROOT_DIR}/isar/
+    sudo install -m 755 ${WORKDIR}/deps.sh ${BUILDCHROOT_DIR}/isar/
 
     # Configure root filesystem
     sudo install -m 755 ${WORKDIR}/configscript.sh ${BUILDCHROOT_DIR}
diff --git a/meta/recipes-devtools/buildchroot/files/build.sh b/meta/recipes-devtools/buildchroot/files/build.sh
index e2dabab..3c80bd7 100644
--- a/meta/recipes-devtools/buildchroot/files/build.sh
+++ b/meta/recipes-devtools/buildchroot/files/build.sh
@@ -4,53 +4,7 @@
 # Copyright (C) 2015-2017 ilbers GmbH
 # Copyright (c) 2018 Siemens AG
 
-set -e
-
-# Create human-readable names
-target_arch=$2
-
-# Notes:
-#   mk-build-deps for jessie and jtretch has different parameter name to specify
-#   host architecture.
-debian_version=$(cut -c1 /etc/debian_version)
-if [ $(($debian_version)) -ge 9 ]; then
-    set_arch="--host-arch $target_arch"
-else
-    set_arch="-a $target_arch"
-fi
-
-# Go to build directory
-cd $1
-
-# To avoid Perl locale warnings:
-export LC_ALL=C
-export LANG=C
-export LANGUAGE=C
-
-# Install command to be used by mk-build-deps
-# Notes:
-#   1) everything before the -y switch is unchanged from the defaults
-#   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"
-
-    # Install all build deps
-    mk-build-deps $set_arch -t "${install_cmd}" -i -r debian/control
-) 42>/dpkg.lock
+source /isar/common.sh
 
 # If autotools files have been created, update their timestamp to
 # prevent them from being regenerated
diff --git a/meta/recipes-devtools/buildchroot/files/common.sh b/meta/recipes-devtools/buildchroot/files/common.sh
new file mode 100644
index 0000000..b7551eb
--- /dev/null
+++ b/meta/recipes-devtools/buildchroot/files/common.sh
@@ -0,0 +1,28 @@
+#!/bin/bash
+#
+# This software is a part of ISAR.
+# Copyright (C) 2015-2017 ilbers GmbH
+# Copyright (c) 2018 Siemens AG
+
+set -e
+
+# Create human-readable names
+target_arch=$2
+
+# Notes:
+#   mk-build-deps for jessie and jtretch has different parameter name to specify
+#   host architecture.
+debian_version=$(cut -c1 /etc/debian_version)
+if [ $(($debian_version)) -ge 9 ]; then
+    set_arch="--host-arch $target_arch"
+else
+    set_arch="-a $target_arch"
+fi
+
+# Go to build directory
+cd $1
+
+# To avoid Perl locale warnings:
+export LC_ALL=C
+export LANG=C
+export LANGUAGE=C
diff --git a/meta/recipes-devtools/buildchroot/files/deps.sh b/meta/recipes-devtools/buildchroot/files/deps.sh
new file mode 100644
index 0000000..854a4d5
--- /dev/null
+++ b/meta/recipes-devtools/buildchroot/files/deps.sh
@@ -0,0 +1,32 @@
+#!/bin/bash
+#
+# This software is a part of ISAR.
+# Copyright (C) 2015-2017 ilbers GmbH
+# Copyright (c) 2018 Siemens AG
+
+source /isar/common.sh
+
+# Install command to be used by mk-build-deps
+# Notes:
+#   1) everything before the -y switch is unchanged from the defaults
+#   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"
+
+    # Install all build deps
+    mk-build-deps $set_arch -t "${install_cmd}" -i -r debian/control
+) 42>/dpkg.lock
diff --git a/meta/recipes-kernel/linux-module/module.inc b/meta/recipes-kernel/linux-module/module.inc
index 3075f44..3a3cab1 100644
--- a/meta/recipes-kernel/linux-module/module.inc
+++ b/meta/recipes-kernel/linux-module/module.inc
@@ -17,7 +17,7 @@ AUTOLOAD ?= "0"
 
 inherit dpkg
 
-dpkg_runbuild_prepend() {
+do_prepare_prepend() {
     cp -r ${WORKDIR}/debian ${S}/
     sed -i -e 's/@PN@/${PN}/g' -e 's/@PV@/${PV}/g' \
            -e 's/@KERNEL_NAME@/${KERNEL_NAME}/g' \
-- 
2.11.0