Adding better handling for kernel cmdline arguments

Author: rdoxenham

RELEASE_NOTES.md

@@ -4,6 +4,10 @@
 
 ## General
 
+* Adds better handling for user-supplied kernel cmdline arguments:
+  * Removes duplicates found between default and user-supplied arguments in all scenarios (RAW cmdline, ISO cmdline, and `kexec` config.bootoptions).
+  * Removes the reliance on `rd.kiwi.install.pass.bootparam` to pull user-supplied arguments post-`kexec` (with SelfInstall ISO).
+
 ## API
 
 ### Image Definition Changes
@@ -14,6 +18,7 @@
 
 * [#593](https://github.com/suse-edge/edge-image-builder/issues/593) - OS files script should mount /var
 * [#594](https://github.com/suse-edge/edge-image-builder/issues/594) - Package install breaks package resolution if packages is already installed on root OS
+* [#604](https://github.com/suse-edge/edge-image-builder/issues/604) - Handle kernel arguments better, especially when duplicated
 
 ---
 

pkg/build/grub.go

@@ -27,9 +27,11 @@ func (b *Builder) generateGRUBGuestfishCommands() (string, error) {
 
 	argLine := strings.Join(b.context.ImageDefinition.OperatingSystem.KernelArgs, " ")
 	values := struct {
-		KernelArgs string
+		KernelArgs     string
+		KernelArgsList []string
 	}{
-		KernelArgs: argLine,
+		KernelArgs:     argLine,
+		KernelArgsList: b.context.ImageDefinition.OperatingSystem.KernelArgs,
 	}
 
 	snippet, err := template.Parse("guestfish-snippet", guestfishSnippet, values)

pkg/build/iso.go

@@ -110,6 +110,8 @@ func (b *Builder) writeIsoScript(templateContents, outputFilename string) error
 		ArtefactsDir        string
 		InstallDevice       string
 		KernelArgs          string
+		KernelArgsList      []string
+		Arch                string
 	}{
 		IsoExtractDir:       isoExtractPath,
 		RawExtractDir:       rawExtractPath,
@@ -119,6 +121,8 @@ func (b *Builder) writeIsoScript(templateContents, outputFilename string) error
 		ArtefactsDir:        b.context.ArtefactsDir,
 		InstallDevice:       b.context.ImageDefinition.OperatingSystem.IsoConfiguration.InstallDevice,
 		KernelArgs:          argLine,
+		KernelArgsList:      b.context.ImageDefinition.OperatingSystem.KernelArgs,
+		Arch:                string(b.context.ImageDefinition.Image.Arch),
 	}
 
 	contents, err := template.Parse("iso-script", templateContents, arguments)

pkg/build/templates/grub/guestfish-snippet.tpl

@@ -1,6 +1,11 @@
 # Configure GRUB defaults
 # - So that the update below, and later`transactional-update grub.cfg` will persist the changes
 download /etc/default/grub /tmp/grub
+# Remove original kernel arguments that match desired kernelArgs that have values
+{{ range .KernelArgsList -}}
+! sed -i "/^GRUB_CMDLINE_LINUX_DEFAULT/ s/$(echo {{ . }} | cut -f1 -d"=")=[^=]//" /tmp/grub
+{{ end -}}
+# Add in the new ones
 ! sed -i '/^GRUB_CMDLINE_LINUX_DEFAULT="/ s/"$/ {{.KernelArgs}} "/' /tmp/grub
 upload /tmp/grub /etc/default/grub
 

pkg/build/templates/rebuild-iso.sh.tpl

@@ -35,9 +35,33 @@ echo -e "set timeout=3\nset timeout_style=menu\n$(cat ${ISO_EXTRACT_DIR}/boot/gr
 sed -i '/root=install:CDLABEL=INSTALL/ s|$| rd.kiwi.oem.installdevice={{.InstallDevice}} |' ${ISO_EXTRACT_DIR}/boot/grub2/grub.cfg
 {{ end -}}
 
-# Ensure that kernel arguments are appended to ISO grub.cfg so they are applied to firstboot via kexec
 {{ if (gt (len .KernelArgs) 0) -}}
-sed -i '/root=install:CDLABEL=INSTALL/ s|$| rd.kiwi.install.pass.bootparam {{.KernelArgs}} |' ${ISO_EXTRACT_DIR}/boot/grub2/grub.cfg
+# Remove all original kernel arguments from ISO command line that match input kernelArgs *and* have values
+{{ range .KernelArgsList -}}
+value=$(echo {{ . }} | cut -f1 -d"=")
+sed -i "s/$value=[^=]//" ${ISO_EXTRACT_DIR}/boot/grub2/grub.cfg
+{{ end -}}
+
+# Unpack the initrd from the SelfInstall ISO and copy the early microcode into new initrd
+mkdir -p ${ISO_EXTRACT_DIR}/temp-initram/early/ ${ISO_EXTRACT_DIR}/temp-initram/main/
+cp ${ISO_EXTRACT_DIR}/boot/{{ .Arch }}/loader/initrd ${ISO_EXTRACT_DIR}/temp-initram/
+cd ${ISO_EXTRACT_DIR}/temp-initram/early && lsinitrd --unpackearly ${ISO_EXTRACT_DIR}/temp-initram/initrd
+find . -print0 | cpio --null --create --format=newc > ${ISO_EXTRACT_DIR}/temp-initram/new-initrd
+# NOTE: We pipe the following command to true to avoid issues with mknod failing when unprivileged
+cd ${ISO_EXTRACT_DIR}/temp-initram/main && lsinitrd --unpack ${ISO_EXTRACT_DIR}/temp-initram/initrd || true
+
+# Remove the original kernel arguments from initrd config that match input kernelArgs and add desired ones
+{{ range .KernelArgsList -}}
+value=$(echo {{ . }} | cut -f1 -d"=")
+sed -i "s/$value=[^=]//" config.bootoptions
+{{ end -}}
+sed -i '1s|$| {{ .KernelArgs }}|' config.bootoptions
+
+# Repack the contents of the initrd into the new file, including the new kernel cmdline arguments
+find . | cpio --create --format=newc >> ${ISO_EXTRACT_DIR}/temp-initram/new-initrd
+
+# Add the desired kernel cmdline arguments to the ISO kernel cmdline so they're available during deployment
+sed -i '/root=install:CDLABEL=INSTALL/ s|$| {{.KernelArgs}} |' ${ISO_EXTRACT_DIR}/boot/grub2/grub.cfg
 {{ end -}}
 
 cd ${RAW_EXTRACT_DIR}
@@ -51,5 +75,8 @@ xorriso -indev ${ISO_SOURCE} \
         -map ${ARTEFACTS_DIR} /artefacts \
 {{- if .InstallDevice }}
         -map ${ISO_EXTRACT_DIR}/boot/grub2/grub.cfg /boot/grub2/grub.cfg \
+{{- end }}
+{{- if (gt (len .KernelArgs) 0) }}
+        -map ${ISO_EXTRACT_DIR}/temp-initram/new-initrd /boot/{{ .Arch }}/loader/initrd \
 {{- end }}
         -boot_image any replay -changes_pending yes