[gnome-continuous-yocto/gnomeostree-3.28-rocko: 2515/8267] qemuboot: write the full kernel filename, not the link name

[Emmanuele Bassi <ebassi src gnome org>]

commit 7352d35d739acef65cfddc1923d34aa62c6f0f4c
Author: Joshua Lock <joshua g lock intel com>
Date:   Sun Sep 18 00:39:24 2016 -0700

    qemuboot: write the full kernel filename, not the link name
    
    KERNEL_IMAGETYPE gives the filename of a symlink to the kernel,
    which may not be available i.e. if the user downloads some build
    artefacts to run on a local machine. It's also possible that the
    link will point to a newer kernel than was intended for use with
    the rootfs in the qemuboot.conf.
    
    It's much more reliable to read the name of the file
    KERNEL_IMAGETYPE is linking to and assign the full filename to
    QB_DEFAULT_KERNEL.
    
    [YOCTO #10285]
    
    (From OE-Core rev: d57bdacab13605ada4cd9e9159c18fdcd6eeacbc)
    
    Signed-off-by: Joshua Lock <joshua g lock intel com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 meta/classes/qemuboot.bbclass |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/meta/classes/qemuboot.bbclass b/meta/classes/qemuboot.bbclass
index 8500c73..0892db3 100644
--- a/meta/classes/qemuboot.bbclass
+++ b/meta/classes/qemuboot.bbclass
@@ -63,6 +63,14 @@ python write_qemuboot_conf() {
     cf.add_section('config_bsp')
     for k in build_vars + qb_vars:
         cf.set('config_bsp', k, '%s' % d.getVar(k, True))
+
+    # QB_DEFAULT_KERNEL's value of KERNEL_IMAGETYPE is the name of a symlink
+    # to the kernel file, which hinders relocatability of the qb conf.
+    # Read the link and replace it with the full filename of the target.
+    kernel_link = os.path.join(d.getVar('DEPLOY_DIR_IMAGE', True), d.getVar('QB_DEFAULT_KERNEL', True))
+    kernel = os.readlink(kernel_link)
+    cf.set('config_bsp', 'QB_DEFAULT_KERNEL', kernel)
+
     with open(qemuboot, 'w') as f:
         cf.write(f)