[PATCH v3] meta: image: detect broken symlinks

[Henning Schild <henning.schild@siemens.com>]

Switch get_image_name from os.path.lexists to os.path.exists because the
latter detects broken symlinks correctly. Also support older debian
versions where the symlinks in the rootfs are absolute
Also change scripts/start_vm to handle the case where no initrd is
present.

Issue:
If you build a kernel without CONFIG_BLK_DEV_INITRD the postinst hook will
still call "linux-update-symlinks" and create a broken symlink. After
that os.path.lexists will return True and "sudo cp" in do_copy_boot_files
will fail.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
---
 meta/classes/image.bbclass |  5 ++++-
 scripts/start_vm           | 11 +++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
index 2c255f4..6a705fc 100644
--- a/meta/classes/image.bbclass
+++ b/meta/classes/image.bbclass
@@ -8,8 +8,11 @@ IMAGE_ROOTFS   = "${WORKDIR}/rootfs"
 def get_image_name(d, name_link):
     S = d.getVar("IMAGE_ROOTFS", True)
     path_link = os.path.join(S, name_link)
-    if os.path.lexists(path_link):
+    if os.path.exists(path_link):
         return os.path.basename(os.path.realpath(path_link))
+    if os.path.islink(path_link):
+        return get_image_name(d, os.path.relpath(os.path.realpath(path_link),
+                                                 '/'))
     return ""
 
 # These variables are used by wic and start_vm
diff --git a/scripts/start_vm b/scripts/start_vm
index b7b5e17..0d1d554 100755
--- a/scripts/start_vm
+++ b/scripts/start_vm
@@ -25,8 +25,8 @@ qemu-system-$QEMU_ARCH \\\\\n\
     -M $QEMU_MACHINE \\\\\n\
     $QCPU\\\\\n\
     -nographic \\\\\n\
-    -kernel \$IMAGE_DIR/$KERNEL_IMAGE \\\\\n\
-    -initrd \$IMAGE_DIR/$INITRD_IMAGE \\\\\n\
+    -kernel \$QKERNEL \\\\\n\
+    -initrd \$QINITRD \\\\\n\
     -append \"console=$MACHINE_SERIAL root=/dev/$ROOTFS_DEV rw\" \\\\\n\
     $EXTRA_ARGS \\\\\n\
     $root1"
@@ -38,8 +38,8 @@ qemu-system-$QEMU_ARCH \\\\\n\
 	-M $QEMU_MACHINE \
 	$QCPU \
 	-nographic \
-	-kernel $IMAGE_DIR/$KERNEL_IMAGE \
-	-initrd $IMAGE_DIR/$INITRD_IMAGE \
+	-kernel $QKERNEL \
+	-initrd $QINITRD \
 	-append "console=$MACHINE_SERIAL root=/dev/$ROOTFS_DEV rw" \
 	$EXTRA_ARGS \
 	$root2
@@ -118,6 +118,9 @@ readonly ROOTFS_IMAGE=isar-image-base-debian-$DISTRO-qemu$ARCH.ext4.img
 
 eval $(bitbake -e multiconfig:qemu$ARCH-$DISTRO:isar-image-base | grep "^KERNEL_IMAGE=")
 eval $(bitbake -e multiconfig:qemu$ARCH-$DISTRO:isar-image-base | grep "^INITRD_IMAGE=")
+QKERNEL=$IMAGE_DIR/$KERNEL_IMAGE
+QINITRD=/dev/null
+[ -n "$INITRD_IMAGE" ] && QINITRD=$IMAGE_DIR/$INITRD_IMAGE
 
 readonly ISARROOT="$(dirname "$0")"/..
 
-- 
2.16.1