[PATCH v2 3/7] Rework rootfs generation to make a cpio archive

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Rename the script as we're going to use it for ARM64 shortly, and have it take
a tar or cpio parameter to determine the output format.

Turn it into a proper bash script, and provide the cpio form under the new
artefact naming scheme.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Michal Orzel <michal.orzel@xxxxxxx>
CC: Doug Goldstein <cardoe@xxxxxxxxxx>
CC: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>

v2:
 * Use -print0
 * Don't dedup $PATHS.  It's going to change between cpio and tar in
   subsequent patches.
---
 .gitlab-ci.yml                                |  9 +++++++-
 ...6_64-rootfs-alpine.sh => alpine-rootfs.sh} | 21 +++++++++++++++++--
 2 files changed, 27 insertions(+), 3 deletions(-)
 rename scripts/{x86_64-rootfs-alpine.sh => alpine-rootfs.sh} (71%)

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 790a6d9f9896..b7d187168df2 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -42,6 +42,13 @@ linux-6.6.86-arm64:
 #
 # x86_64 artifacts
 #
+alpine-3.18-x86_64-rootfs:
+  extends: .x86_64-artifacts
+  script:
+    - ./scripts/alpine-rootfs.sh cpio
+  variables:
+    CONTAINER: alpine:3.18-x86_64-base
+
 linux-6.6.56-x86_64:
   extends: .x86_64-artifacts
   script: ./scripts/build-linux.sh
@@ -62,7 +69,7 @@ x86_64-kernel-linux-6.6.56:
 x86_64-rootfs-alpine-3.18:
   extends: .x86_64-artifacts
   script:
-    - . scripts/x86_64-rootfs-alpine.sh
+    - ./scripts/alpine-rootfs.sh tar
   variables:
     CONTAINER: alpine:3.18-x86_64-base
 
diff --git a/scripts/x86_64-rootfs-alpine.sh b/scripts/alpine-rootfs.sh
similarity index 71%
rename from scripts/x86_64-rootfs-alpine.sh
rename to scripts/alpine-rootfs.sh
index b70b3a54ede5..75e2f8648ce5 100755
--- a/scripts/x86_64-rootfs-alpine.sh
+++ b/scripts/alpine-rootfs.sh
@@ -1,4 +1,9 @@
+#!/bin/bash
+
+set -eu
+
 WORKDIR="${PWD}"
+COPYDIR="${WORKDIR}/binaries"
 
 apk update
 
@@ -56,5 +61,17 @@ passwd -d "root" root
 
 # Create rootfs
 cd /
-tar cvzf "${WORKDIR}/binaries/initrd.tar.gz" \
-    bin dev etc home init lib mnt opt root sbin usr var
+case $1 in
+    cpio)
+        PATHS="bin dev etc home init lib mnt opt root sbin usr var"
+        find $PATHS -print0 | cpio -0 -H newc -o | gzip > 
"${COPYDIR}/rootfs.cpio.gz"
+
+        # Print the contents for the build log
+        zcat "${COPYDIR}/rootfs.cpio.gz" | cpio -tv
+        ;;
+
+    tar)
+        PATHS="bin dev etc home init lib mnt opt root sbin usr var"
+        tar cvzf "${COPYDIR}/initrd.tar.gz" $PATHS
+        ;;
+esac
-- 
2.39.5