Add extra_boot_params boot parameters into miniboot parms

When the --param extra_boot_params argument is given, we need to parse
the given boot parameters and include them in the miniboot boot options
by adding them into the BOOT_ARGS_COMMON variable

Example:
For '--param extra_boot_params=arg1=1,arg2=two'

The following is added to the miniboot kernel options:
extra_boot_params=arg1=1,arg2=two arg1=1 arg2=two

Where 'extra_boot_params=arg1=1,arg2=two' is required for parsing by
miniboot.cfg and 'arg1=1 arg2=two' are the actual boot parameters
applied during boot of the miniboot bootimage.iso.

Test Plan
PASS:
- Verify that extra_boot_params is parsed both the 'extra_boot_params='
  as well as separate miniboot kernel options (see above example)
- Verify that the miniboot comes up with the kernel options in its
  /proc/cmdline (i.e., the initial miniboot ISO boots with the
  configured extra options)
- Tested with the follow input:
    --param extra_boot_params=arg1=1,arg2=2
    --param extra_boot_params=arg1=1
    --param extra_boot_params=arg1

Closes-Bug: 2023407
Depends-On: https://review.opendev.org/c/starlingx/distcloud/+/885758

Signed-off-by: Kyle MacLeod <kyle.macleod@windriver.com>
Change-Id: Iae094d9f7746e8d2963e137ab809376d75ad1bca

utilities/platform-util/scripts/gen-bootloader-iso.sh

@@ -490,6 +490,27 @@ function generate_boot_cfg {
         BOOT_ARGS_COMMON="${BOOT_ARGS_COMMON} debug_kickstart"
     fi
     BOOT_ARGS_COMMON="${BOOT_ARGS_COMMON} ${PARAM_LIST}"
+
+    # Search the install kernel command line for the 'extra_boot_params='
+    # option. If present, propagate the value into our BOOT_ARGS_COMMON, so
+    # that any extra boot parameters are also provided during the boot from
+    # miniboot ISO.
+    # Multiple parameters can be separated by ',' here; we want to
+    # split them out to be space-separated when adding to kernel arguments.
+    # e.g.: for extra_boot_params=arg1=1,arg2=2, set kernel params: arg1=1 arg2=2
+    local option
+    for option in ${PARAM_LIST}; do
+        if [ "${option%%=*}" = "extra_boot_params" ]; then
+            # Do not include the 'extra_boot_params' string.
+            # Strip out any commas and replace with space.
+            extra_boot_params=${option#*=}               # remove 'extra_boot_params='
+            extra_boot_params=${extra_boot_params//,/ }  # replace all ',' with ' '
+            ilog "Adding extra_boot_params to BOOT_ARGS_COMMON: ${extra_boot_params}"
+            BOOT_ARGS_COMMON="${BOOT_ARGS_COMMON} ${extra_boot_params}"
+            break
+        fi
+    done
+
     # Uncomment for debugging:
     #BOOT_ARGS_COMMON="${BOOT_ARGS_COMMON} instsh=2 instpost=shell"
     log_verbose "BOOT_ARGS_COMMON: $BOOT_ARGS_COMMON"