arm-autonomy: Add external guests to host image

Add ARM_AUTONOMY_HOST_IMAGE_EXTERN_GUESTS variable to let user specifiy
a list of guests to be included directly in the host image.
The variable can be set to a space separated list of full path to
xenguest image files or SRC_URI compatible urls. Each entry can also
have a ';guestname=NAME' argument to set the destination name of the
guest added.

Change-Id: I4fc5e53df979b792ad930066a068ad1d4512c991
Issue-Id: SCM-767
Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Diego Sueiro <diego.sueiro@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm-autonomy/recipes-core/images/arm-autonomy-host-image-minimal.bb

@@ -5,6 +5,31 @@ DESCRIPTION = "Arm Autonomy stack host minimal image"
 inherit core-image
 
 LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"
+
+# The ARM_AUTONOMY_HOST_IMAGE_EXTERN_GUESTS variable can be used to include in the
+# image one or several xenguest images.
+# The list must be space separated and each entry must have the following
+# format: URL[;guestname=NAME]
+#  - URL can be the full path to a file or a Yocto compatible SRC_URI url
+#  - guestname=NAME can be used to specify the name of the guest. If not
+#    specified the basename of the file (without .xenguest extension) is used.
+#  Here are examples of values:
+#  /home/mydir/myguest.xenguest;guestname=guest1
+#  http://www.url.com/testguest.xenguest
+#
+#  If you are using the output of an other Yocto project, you should use the
+#  full path syntax instead of the Yocto SRC_URI to be able to use the
+#  symlink version of your image (as the real file has a new name on each
+#  build as it includes the date). You must not use SRC_URI type file:// as
+#  it will try to include the symlink and not the destination file which will
+#  be detected by the recipe and output an error 'Guest file is a symlink'.
+#
+#  Guests can also be added using a bbapend to this recipe by adding entries
+#  to SRC_URI with parameter ;guestname=NAME to specify the destination
+#  guestname. The parameter guestname must be present as it is used to detect
+#  guests to be added
+ARM_AUTONOMY_HOST_IMAGE_EXTERN_GUESTS ??= ""
 
 # Includes minimal set required to start and manage guest. The xen specific
 # modules are not explicitly included as they are built as part of the kernel
@@ -29,4 +54,64 @@ python __anonymous() {
 
     if bb.utils.contains('DISTRO_FEATURES', 'xen', False, True, d):
         raise bb.parse.SkipRecipe("DISTRO_FEATURES does not contain 'xen'")
+
+    # Check in ARM_AUTONOMY_HOST_IMAGE_EXTERN_GUESTS for extra guests and add them
+    # to SRC_URI with xenguest parameter if not set
+    guestlist = d.getVar('ARM_AUTONOMY_HOST_IMAGE_EXTERN_GUESTS')
+    if guestlist:
+        for guest in guestlist.split():
+            # If the user just specified a file instead of file://FILE, add
+            # the file:// prefix
+            if guest.startswith('/'):
+                guestfile = ''
+                guestname = ''
+                if ';guestname=' in guest:
+                    # user specified a guestname
+                    guestname = guest.split(';guestname=')[1]
+                    guestfile = guest.split(';guestname=')[0]
+                else:
+                    # no guestname so use the basename
+                    guestname = os.path.basename(guest)
+                    guestfile = guest
+                # in case we have a link we need the destination
+                guestfile = os.path.realpath(guestfile)
+
+                # make sure the file exist to give a meaningfull error
+                if not os.path.exists(guestfile):
+                    raise bb.parse.SkipRecipe("ARM_AUTONOMY_HOST_IMAGE_EXTERN_GUESTS entry does not exist: " + guest)
+
+                # In case the file is a symlink make sure we use the destination
+                d.appendVar('SRC_URI',  ' file://' + guestfile + ';guestname=' + guestname)
+            else:
+                # we have a Yocto URL
+                try:
+                    _, _, path, _, _, parm = bb.fetch.decodeurl(guest)
+                    # force guestname param in if not already there
+                    if not 'guestname' in parm:
+                        guest  += ';guestname=' + os.path.basename(path)
+                    d.appendVar('SRC_URI', ' ' + guest)
+                except:
+                    raise bb.parse.SkipRecipe("ARM_AUTONOMY_HOST_IMAGE_EXTERN_GUESTS contains an invalid entry: " + guest)
 }
+
+python add_extern_guests () {
+    # Destination directory on the rootfs
+    guestdir = d.getVar('IMAGE_ROOTFS') + d.getVar('datadir') + '/guests'
+
+    # Parse SRC_URI for files with ;guestname= parameter
+    src_uri = d.getVar('SRC_URI')
+    for entry in src_uri.split():
+        _, _, path, _, _, parm = bb.fetch.decodeurl(entry)
+        if 'guestname' in parm:
+            if os.path.islink(path):
+                bb.fatal("Guest file is a symlink: " + path)
+            bb.utils.mkdirhier(guestdir)
+            dstname = parm['guestname']
+            # Add file extension if not there
+            if not dstname.endswith('.xenguest'):
+                dstname += '.xenguest'
+            bb.utils.copyfile(path, guestdir + '/' + dstname)
+}
+
+IMAGE_PREPROCESS_COMMAND += "add_extern_guests; "
+