Merge pull request #16 from morphis/kmod-support

Build and load binder/ashmem kernel modules on service start

scripts/classic

@@ -0,0 +1,63 @@
+#!/bin/sh
+
+set -e
+
+ROOT=$SNAP_COMMON/classic
+
+# $1: source
+# $2: target
+# $3: if not empty, bind mount will be read-only
+# note that we do NOT clean these up at the end, as the user might start many
+# classic shells in parallel; we could start all of them in their own mount
+# namespace, but that would make the classic shell less useful for
+# developing/debugging the snappy host
+do_bindmount() {
+    if ! mountpoint -q "$ROOT/$2"; then
+        if [ -d "$1" -a ! -L "$1" ]; then
+            mkdir -p "$ROOT/$2"
+        fi
+        mount --make-rprivate --rbind -o rbind "$1" "$ROOT/$2"
+        if [ -n "${3:-}" ]; then
+            mount --rbind -o remount,ro "$1" "$ROOT/$2"
+        fi
+    fi
+}
+
+if [ "$(id -u)" != "0" ]; then
+    echo "needs to run as root"
+    exit 1
+fi
+
+if [ ! -d $ROOT ]; then
+    # IMPORTANT: do not run the classic.create as this will run it with
+    #            snap-confine again and this will cause havoc with current
+    #            snap-confine
+    $SNAP/bin/create
+fi
+
+# FIXME: confinement will prevent this
+do_bindmount /home /home
+do_bindmount /run /run
+do_bindmount /proc /proc
+do_bindmount /sys /sys
+do_bindmount /dev /dev
+do_bindmount / /snappy
+
+SUDO_USER=root
+
+# fix LP: #1619455
+cp -a /var/lib/extrausers/* $ROOT/var/lib/extrausers/
+cp -a /etc/sudoers.d/* $ROOT/etc/sudoers.d/
+
+# assemble command line
+DEVPTS="mount -o mode=666,ptmxmode=666 -t devpts devpts /dev/pts"
+SUDOCMD="sudo debian_chroot=classic -u ${SUDO_USER} -i $@"
+# FIXME: workaround for https://bugs.launchpad.net/snappy/+bug/1611493
+SCRIPT="script --quiet --return --command \"$SUDOCMD\" /dev/null"
+
+CMD="$DEVPTS; $SCRIPT"
+
+systemd-run --quiet --scope --unit=classic-$$.scope --description="Classic shell" chroot "$ROOT" sh -c "$CMD"
+
+# kill leftover processes after exiting, if it's still around
+systemctl stop classic-$$.scope 2>/dev/null || true

scripts/classic-create

@@ -0,0 +1,61 @@
+#!/bin/sh
+
+set -eu
+
+ROOT=$SNAP_COMMON/classic
+
+if [ -d $ROOT ]; then
+    echo "classic already enabled"
+    exit 1
+fi
+
+if [ $(id -u) -ne 0 ]; then
+    echo "This script needs to be called as root" >&2
+    exit 1
+fi
+
+CORE=""
+if [ -e /snap/core/current ]; then
+    CORE="core"
+elif [ -e /snap/ubuntu-core/current ]; then
+    CORE="ubuntu-core"
+else
+    echo "Cannot find core snap"
+    exit 1
+fi
+
+# FIXME: confinement will prevent this
+echo "Creating classic environment"
+VERSION="$(/bin/readlink /snap/${CORE}/current)"
+SNAPROOT="/var/lib/snapd/snaps/${CORE}_${VERSION}.snap"
+/usr/bin/unsquashfs -d $ROOT $SNAPROOT
+mkdir $ROOT/snappy
+
+# enable
+sudo chroot $ROOT /var/lib/classic/enable.sh
+
+# copy important config
+for f in hostname timezone localtime; do
+    cp -a /etc/writable/$f $ROOT/etc/writable
+done
+for f in hosts; do
+    cp -a /etc/$f $ROOT/etc/
+done
+
+
+# don't start services in the chroot on apt-get install
+cat <<EOF > "$ROOT/usr/sbin/policy-rc.d"
+#!/bin/sh
+while true; do
+    case "\$1" in
+      -*) shift ;;
+      makedev) exit 0;;
+      x11-common) exit 0;;
+      *) exit 101;;
+    esac
+done
+EOF
+chmod 755 "$ROOT/usr/sbin/policy-rc.d"
+
+# workaround bug in livecd-rootfs
+chmod 1777 "$ROOT/tmp"

scripts/classic-reset

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+set -eu
+
+ROOT=$SNAP_COMMON/classic
+
+if [ "$(id -u)" != "0" ]; then
+    echo "needs to run as root"
+    exit 1
+fi
+
+for d in /home /run /proc /sys /dev /var/lib/extrausers /etc/sudoers /etc/sudoers.d /snappy; do
+  if mountpoint -q "$ROOT/$d"; then
+    umount "$ROOT/$d"
+  fi
+done
+
+# cleanup
+rm -rf $ROOT

scripts/container-manager.sh

@@ -1,4 +1,5 @@
 #!/bin/sh
+set -x
 
 # We need to put the rootfs somewhere where we can modify some
 # parts of the content on first boot (namely file permissions).
@@ -21,6 +22,50 @@ if [ ! -e $SYSTEM_IMG ]; then
 	exit 1
 fi
 
+build_kernel_modules() {
+	kversion=$1
+
+	rm -rf $SNAP_COMMON/kernel-*
+
+	$SNAP/bin/classic-create || true
+
+	rm -rf $SNAP_COMMON/classic/build
+	mkdir -p $SNAP_COMMON/classic/build
+	cp -rav $SNAP/ashmem $SNAP_COMMON/classic/build/
+	cp -rav $SNAP/binder $SNAP_COMMON/classic/build/
+
+	cat<<EOF > $SNAP_COMMON/classic/build/run.sh
+#!/bin/sh
+set -ex
+apt update
+apt install -y --force-yes linux-headers-$kversion build-essential
+cd /build/ashmem
+make
+cd /build/binder
+make
+EOF
+
+	chmod +x $SNAP_COMMON/classic/build/run.sh
+	$SNAP/bin/classic /build/run.sh
+
+	mkdir -p $SNAP_COMMON/kernel-$kversion
+	cp $SNAP_COMMON/classic/build/ashmem/ashmem_linux.ko \
+		$SNAP_COMMON/kernel-$kversion/
+	cp $SNAP_COMMON/classic/build/binder/binder_linux.ko \
+		$SNAP_COMMON/kernel-$kversion/
+}
+
+load_kernel_modules() {
+	kversion=`uname -r`
+	rmmod ashmem_linux binder_linux || true
+	echo "Loading kernel modules for version $kversion.."
+	insmod $SNAP_COMMON/kernel-$kversion/binder_linux.ko
+	insmod $SNAP_COMMON/kernel-$kversion/ashmem_linux.ko
+	sleep 0.5
+	chmod 666 /dev/binder
+	chmod 666 /dev/ashmem
+}
+
 start() {
 	# Extract ramdisk content instead of trying to bind mount the
 	# cpio image file to allow modifications.
@@ -52,6 +97,13 @@ start() {
 	# possible. See snapcraft.yaml for further details.
 	$SNAP/bin/anbox-bridge.sh start
 
+	kversion=`uname -r`
+	if [ ! -e $SNAP_COMMON/kernel-$kversion ]; then
+		build_kernel_modules $kversion
+	fi
+
+	load_kernel_modules
+
 	exec $SNAP/usr/sbin/aa-exec -p unconfined -- $SNAP/bin/anbox-wrapper.sh container-manager
 }
 
@@ -63,6 +115,8 @@ stop() {
 	umount $ROOTFS_PATH
 
 	$SNAP/bin/anbox-bridge.sh stop
+
+	rmmod ashmem_linux binder_linux || true
 }
 
 case "$1" in

snapcraft.yaml

@@ -29,6 +29,9 @@ parts:
     files:
       system.img: system.img
       ramdisk.img: ramdisk.img
+  kernel-modules:
+    plugin: dump
+    source: kernel
   anbox-common:
     plugin: copy
     source: .
@@ -36,10 +39,16 @@ parts:
       scripts/snap-wrapper.sh: bin/anbox-wrapper.sh
       scripts/container-manager.sh: bin/container-manager.sh
       scripts/anbox-bridge.sh: bin/anbox-bridge.sh
+      scripts/classic: bin/classic
+      scripts/classic-create: bin/classic-create
+      scripts/classic-reset: bin/classic-reset
     snap:
       - bin/anbox-bridge.sh
       - bin/anbox-wrapper.sh
       - bin/container-manager.sh
+      - bin/classic
+      - bin/classic-create
+      - bin/classic-reset
   apparmor:
     plugin: nil
     stage-packages: