[isar-cip-core,v4,5/6] swupdate: Extend sw-description to update efibootguard

Commit Message

Quirin Gylstorff Jan. 8, 2024, 10:25 a.m. UTC

From: Quirin Gylstorff <[e-mail]>

If the variable `SWU_EBG_UPDATE` is set to `1` an additional file
element is added to the sw-description to replace the ebg.

Use python as newlines are part of the sw-description syntax an
therefore cannot be hold in a bitbake variable, see note in[1].

The efibootguard binary has the property 'atomic-install' which
copies the file to a tempory location before replacing the original with
new file[2].

IMPORTANT: Even if the property 'atomic-install' is set FAT does not
support atomic writes or renames so a powercut can still corrupt the
system[3].

[1]: https://docs.yoctoproject.org/bitbake/2.2/bitbake-user-manual/bitbake-user-manual-metadata.html#line-joining
[2]: https://sbabic.github.io/swupdate/sw-description.html#files
[3]: https://lore.kernel.org/linux-fsdevel/20191022105413.pj6i3ydetnfgnkzh@pali/

Signed-off-by: Quirin Gylstorff <[e-mail]>
---
 classes/swupdate.bbclass                    | 34 +++++++++++++++++++--
 recipes-core/images/swu/sw-description.tmpl |  2 +-
 2 files changed, 33 insertions(+), 3 deletions(-)

Patch

diff --git a/classes/swupdate.bbclass b/classes/swupdate.bbclass
index dfe8ef1..0f8ae23 100644
--- a/classes/swupdate.bbclass
+++ b/classes/swupdate.bbclass
@@ -1,7 +1,7 @@ 
 #
 # CIP Core, generic profile
 #
-# Copyright (c) Siemens AG, 2020-2023
+# Copyright (c) Siemens AG, 2020-2024
 #
 # Authors:
 #  Christian Storm <[e-mail]>
@@ -11,6 +11,7 @@ 
 # SPDX-License-Identifier: MIT
 
 inherit template
+inherit efibootguard
 
 SWU_ROOTFS_TYPE ?= "squashfs"
 SWU_ROOTFS_NAME ?= "${IMAGE_FULLNAME}"
@@ -22,6 +23,9 @@  SWU_NAME ?= "cip software update"
 # space separated list of supported hw. Leave empty to leave out
 SWU_HW_COMPAT ?= ""
 
+SWU_EBG_UPDATE ?= ""
+SWU_EFI_BOOT_DEVICE ?= "/dev/disk/by-uuid/4321-DCBA"
+
 SWU_IMAGE_FILE ?= "${DEPLOY_DIR_IMAGE}/${IMAGE_FULLNAME}.swu"
 SWU_DESCRIPTION_FILE ?= "sw-description"
 SWU_ADDITIONAL_FILES ?= "linux.efi ${SWU_ROOTFS_PARTITION_NAME}"
@@ -47,7 +51,14 @@  IMAGE_TEMPLATE_VARS:swu = " \
     SWU_HW_COMPAT_NODE \
     SWU_COMPRESSION_NODE \
     SWU_VERSION \
-    SWU_NAME"
+    SWU_NAME \
+    SWU_FILE_NODES \
+    "
+
+# Add the bootloader file
+def efi_bootloader_name(d):
+    efi_arch = distro_to_efi_arch(d)
+    return "boot{}.efi".format(efi_arch)
 
 # TARGET_IMAGE_UUID needs to be generated before completing the template
 addtask do_transform_template after do_generate_image_uuid
@@ -83,6 +94,25 @@  python add_swu_compression(){
         d.setVar('SWU_COMPRESSION_NODE', '')
 }
 
+SWU_EXTEND_SW_DESCRIPTION += "${@ 'add_ebg_update' if d.getVar('SWU_EBG_UPDATE') == '1' else ''}"
+python add_ebg_update(){
+   efi_boot_loader_file = efi_bootloader_name(d)
+   efi_boot_device = d.getVar('SWU_EFI_BOOT_DEVICE')
+   swu_ebg_update_node = f""",
+   {{
+          filename = "{efi_boot_loader_file}";
+          path = "EFI/BOOT/{efi_boot_loader_file}";
+          device = "{efi_boot_device}";
+          filesystem = "vfat";
+          sha256 = "{efi_boot_loader_file}-sha256";
+          properties: {{
+               atomic-install = "true";
+          }};
+   }}
+   """
+   d.appendVar('SWU_FILE_NODES', swu_ebg_update_node)
+   d.appendVar('SWU_ADDITIONAL_FILES', " " + efi_boot_loader_file)
+}
 
 # convert between swupdate compressor name and imagetype extension
 def get_swu_compression_type(d):
diff --git a/recipes-core/images/swu/sw-description.tmpl b/recipes-core/images/swu/sw-description.tmpl
index 6b53a3c..c52372c 100644
--- a/recipes-core/images/swu/sw-description.tmpl
+++ b/recipes-core/images/swu/sw-description.tmpl
@@ -34,5 +34,5 @@  software =
                         subtype = "kernel";
             };
             sha256 = "linux.efi-sha256";
-    });
+    }${SWU_FILE_NODES});
 }