From b29e8c73459e205c223263a63fb2a35b0d0c2f67 Mon Sep 17 00:00:00 2001
From: Shrikumar Sharma <shrikumar.sharma@windriver.com>
Date: Tue, 6 Dec 2022 13:44:11 +0000
Subject: [PATCH] Preserve persistent backup when invalid persistent_size
 provided

Miniboot wipes the backup-partition when the persistent size
is set to a value less than the existing size. The expectation is
that the install should fail and the contents of platform-backup
should be preserved.

This fix solves the issue by failing the installation during the
ks-early phase, where the provided persistent size value in the
kernel commandline can be read, and no disk operations have been
performed.

Test Plan:
PASS: Verify that installation with valid parameters passes.

PASS: Verify that reinstall fails if persistent_size less
      than the current persistent_size is provided.

PASS: Verify that contents of /opt/platform-backup are preserved
      when persistent_size less than the current size is
      provided.

PASS: Verify that reinstall fails if persistent_size greater
      than the size of the rootfs device is provided.

PASS: Verify that the contents of /opt/platform-backup are
      preserved when persistent-size greater than size of rootfs
      device is provided.

Closes-Bug: 1998932

Signed-off-by: Shrikumar Sharma <shrikumar.sharma@windriver.com>
Change-Id: I51351cb14cdcfa63b4b5839d935589d997b5403a
---
 kickstart/files/miniboot.cfg | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/kickstart/files/miniboot.cfg b/kickstart/files/miniboot.cfg
index 325fe767..b0a71161 100644
--- a/kickstart/files/miniboot.cfg
+++ b/kickstart/files/miniboot.cfg
@@ -980,6 +980,32 @@ for arg in $*; do
     esac
 done
 
+# Handle persistent_size setting.
+# If the persistent_size is less than the size of the existing persistent backup,
+# then the installation process must terminate and exit.
+
+if [ -n "${persistent_size}" ]; then
+    part=$(readlink -f "/dev/disk/by-partlabel/platform_backup")
+    device=$(readlink -f "${rootfs_device}")
+
+    ilog "Persistent backup is in ${part}"
+
+    MAX_SIZE=$(parted -s ${device} unit MiB print | grep "Disk ${device}:" | awk '{print $3}' | sed 's/[^C0-9]*//g')
+    CURRENT_PERSISTENT_SIZE=$(parted -s ${part} unit MiB print | grep ${part} | awk '{print $3}' | sed 's/[^C0-9]*//g')
+    ilog "Current size of persistent backup is ${CURRENT_PERSISTENT_SIZE}"
+    ilog "Max size of ${device} is ${MAX_SIZE}"
+
+    if [ ${persistent_size} -lt ${CURRENT_PERSISTENT_SIZE} ]; then
+        ilog "Provided persistent_size (${persistent_size}) is less than ${CURRENT_PERSISTENT_SIZE}"
+        report_failure_with_msg "Persistent size setting is less than current backup size (${CURRENT_PERSISTENT_SIZE})"
+    fi
+
+    if [ ${persistent_size} -gt ${MAX_SIZE} ]; then
+        ilog "Provided persistent_size (${persistent_size}) is greater than ${MAX_SIZE}"
+        report_failure_with_msg "Persistent size setting is greater than maximum allowable size (${MAX_SIZE})"
+    fi
+fi
+
 # Note: This is equivalent to pre_disk_setup_common.cfg
 
 # Name   : check_execs
@@ -1669,12 +1695,8 @@ if [ "${controller}" = true ] ; then
         # Default backup partition size in MiB
         ilog "Platform Backup persistent size not on command line ; defaulting to ${BACKUP_SIZE}"
     else
-        if [ ${persistent_size} -lt ${BACKUP_SIZE} ] ; then
-            report_failure_with_msg "Cannot set persistent_size smaller than ${BACKUP_SIZE} MiB"
-        else
-            ilog "Using Platform Backup persistent size from boot command: ${persistent_size}"
-            BACKUP_SIZE=${persistent_size}
-        fi
+        ilog "Using Platform Backup persistent size from boot command: ${persistent_size}"
+        BACKUP_SIZE=${persistent_size}
     fi
     backup_part_extension_required=0
     if [ ${BACKUP_PART_CURRENT_SIZE} -gt 0 ]; then