[RFC][PATCH 4/6] buildchroot: Add mount/umount for 'base-apt'

[Alexander Smirnov <asmirnov@ilbers.de>]

'base-apt' should be avaialble in buildchroot to have possibility
to install build dependencies for packages being built. Mounting is
performed in dedicated task buildchroot:do_prepare. To implement
umounting, the bitbake events are used. This patch registers handler
for build complete event which performs cleanup.

Signed-off-by: Alexander Smirnov <asmirnov@ilbers.de>
---
 meta-isar/conf/local.conf.sample                 |  3 +++
 meta/classes/dpkg-base.bbclass                   |  2 +-
 meta/classes/isar-events.bbclass                 | 21 +++++++++++++++++++++
 meta/recipes-devtools/buildchroot/buildchroot.bb | 11 +++++++++++
 4 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 meta/classes/isar-events.bbclass

diff --git a/meta-isar/conf/local.conf.sample b/meta-isar/conf/local.conf.sample
index 2da803b..acced81 100644
--- a/meta-isar/conf/local.conf.sample
+++ b/meta-isar/conf/local.conf.sample
@@ -167,3 +167,6 @@ REPREPRO_LOCK_ATTEMPTS = "16"
 # List of images, wich dependencies will be pre-fetched and put in base-apt.
 # This will guarantee image building reproducibility.
 BASE_APT_IMAGES ?= "isar-image-base isar-image-debug"
+
+# Add event handlers for bitbake
+INHERIT += "isar-events"
diff --git a/meta/classes/dpkg-base.bbclass b/meta/classes/dpkg-base.bbclass
index c61f9a6..bc8fab8 100644
--- a/meta/classes/dpkg-base.bbclass
+++ b/meta/classes/dpkg-base.bbclass
@@ -2,7 +2,7 @@
 # Copyright (C) 2017 Siemens AG
 
 # Add dependency from buildchroot creation
-do_build[depends] = "buildchroot:do_build"
+do_build[depends] = "buildchroot:do_prepare"
 
 # Each package should have its own unique build folder, so use
 # recipe name as identifier
diff --git a/meta/classes/isar-events.bbclass b/meta/classes/isar-events.bbclass
new file mode 100644
index 0000000..6ccda99
--- /dev/null
+++ b/meta/classes/isar-events.bbclass
@@ -0,0 +1,21 @@
+# Isar event handlers.
+#
+# This software is a part of ISAR.
+# Copyright (C) 2015-2017 ilbers GmbH
+
+addhandler isar_handler
+
+python isar_handler () {
+    import subprocess
+
+    devnull = open(os.devnull, 'w')
+
+    if isinstance(e, bb.event.BuildCompleted):
+        bchroot = d.getVar('BUILDCHROOT_DIR', True)
+
+        # Clean up buildchroot
+        subprocess.call('/usr/bin/sudo /bin/umount ' + bchroot + '/proc || /bin/true', stdout=devnull, stderr=devnull, shell=True)
+        subprocess.call('/usr/bin/sudo /bin/umount ' + bchroot + '/apt || /bin/true', stdout=devnull, stderr=devnull, shell=True)
+
+    devnull.close()
+}
diff --git a/meta/recipes-devtools/buildchroot/buildchroot.bb b/meta/recipes-devtools/buildchroot/buildchroot.bb
index 4d773f9..1fad2f8 100644
--- a/meta/recipes-devtools/buildchroot/buildchroot.bb
+++ b/meta/recipes-devtools/buildchroot/buildchroot.bb
@@ -80,7 +80,18 @@ do_build() {
     # Install package builder script
     sudo install -m 755 ${WORKDIR}/build.sh ${BUILDCHROOT_DIR}
 
+    # Create share point for apt
+    sudo install -d ${BUILDCHROOT_DIR}/apt
+
     # Configure root filesystem
     sudo chroot ${BUILDCHROOT_DIR} /configscript.sh
     _do_build_cleanup
 }
+
+do_prepare[nostamp] = "1"
+
+do_prepare() {
+    sudo mount --bind ${BASE_APT_DIR}/apt ${BUILDCHROOT_DIR}/apt
+}
+
+addtask prepare after do_build
-- 
2.1.4