wic: Add --no-fstab-update part option

When embedding a rootfs image (e.g. 'rootfs-dir') as a partition we
might want to keep the stock fstab for that image. In such a case, use
this option to not update the fstab and use the stock one instead.

This option allows you to specify which partitions get the fstab
updated and which get the stock fstab.

The option matches the argument you can pass to wic itself where the
same action is performed but for all the partitions.

Example:
    part /export --source rootfs --rootfs-dir=hockeycam-image
--fstype=ext4 --label export --align 1024 --no-fstab-update

    part / --source rootfs --fstype=ext4 --label rootfs --align 1024

(From OE-Core rev: ab4c95af8ecd15dc136194ab761afae756db5803)

Signed-off-by: Daniel Gomez <daniel@qtec.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/wic/help.py

@@ -991,6 +991,9 @@ DESCRIPTION
                              multiple partitions and we want to keep the right
                              permissions and usernames in all the partitions.
 
+         --no-fstab-update: This option is specific to wic. It does not update the
+                            '/etc/fstab' stock file for the given partition.
+
          --extra-space: This option is specific to wic. It adds extra
                         space after the space filled by the content
                         of the partition. The final size can go

scripts/lib/wic/ksparser.py

@@ -185,6 +185,7 @@ class KickStart():
         part.add_argument('--use-uuid', action='store_true')
         part.add_argument('--uuid')
         part.add_argument('--fsuuid')
+        part.add_argument('--no-fstab-update', action='store_true')
 
         bootloader = subparsers.add_parser('bootloader')
         bootloader.add_argument('--append')

scripts/lib/wic/partition.py

@@ -54,6 +54,7 @@ class Partition():
         self.uuid = args.uuid
         self.fsuuid = args.fsuuid
         self.type = args.type
+        self.no_fstab_update = args.no_fstab_update
         self.updated_fstab_path = None
         self.has_fstab = False
         self.update_fstab_in_rootfs = False
@@ -286,7 +287,7 @@ class Partition():
             (self.fstype, extraopts, rootfs, label_str, self.fsuuid, rootfs_dir)
         exec_native_cmd(mkfs_cmd, native_sysroot, pseudo=pseudo)
 
-        if self.updated_fstab_path and self.has_fstab:
+        if self.updated_fstab_path and self.has_fstab and not self.no_fstab_update:
             debugfs_script_path = os.path.join(cr_workdir, "debugfs_script")
             with open(debugfs_script_path, "w") as f:
                 f.write("cd etc\n")
@@ -350,7 +351,7 @@ class Partition():
         mcopy_cmd = "mcopy -i %s -s %s/* ::/" % (rootfs, rootfs_dir)
         exec_native_cmd(mcopy_cmd, native_sysroot)
 
-        if self.updated_fstab_path and self.has_fstab:
+        if self.updated_fstab_path and self.has_fstab and not self.no_fstab_update:
             mcopy_cmd = "mcopy -i %s %s ::/etc/fstab" % (rootfs, self.updated_fstab_path)
             exec_native_cmd(mcopy_cmd, native_sysroot)
 

scripts/lib/wic/plugins/source/rootfs.py

@@ -218,7 +218,7 @@ class RootfsPlugin(SourcePlugin):
             # Update part.has_fstab here as fstab may have been added or
             # removed by the above modifications.
             part.has_fstab = os.path.exists(os.path.join(new_rootfs, "etc/fstab"))
-            if part.update_fstab_in_rootfs and part.has_fstab:
+            if part.update_fstab_in_rootfs and part.has_fstab and not part.no_fstab_update:
                 fstab_path = os.path.join(new_rootfs, "etc/fstab")
                 # Assume that fstab should always be owned by root with fixed permissions
                 install_cmd = "install -m 0644 %s %s" % (part.updated_fstab_path, fstab_path)