liveinit: use boot parameter "nop=wipe" to erase existing persistent data.

Sometimes your Slackware Live develops issues because the persistent data
storage is conflicting with new packages or data which you added to the
Live OS.  This can be fixed by erasing persistent data, thereby reverting
the Live OS to its initial state - i.e. when the USB stick was booted
for the first time.
For this purpose the functionality of the existing "nop" boot parameter
was extended to allow the '=' and specifying a value of 'wipe'.

Note that the persistent data will be wiped before the Live OS boots, and
it does not matter if you are using a persistence directory or a container
file for storing persistent data.

This wipe includes all your persistent personal data in /home/
unless you have moved your /home into a container file on the USB stick.

1 files changed, 16 insertions, 0 deletions

diff --git a/liveinit b/liveinit
index cb3f9d2..68a0713 100755
--- a/liveinit
+++ b/liveinit
@@ -48,6 +48,9 @@ LIVEPATH=""
 # to avoid anything that writes to disk after we copy the OS to RAM.
 VIRGIN=0
 
+# If set to '1', existing persistent data will be wiped:
+WIPE_PERSISTENCE=0
+
 # Used for debugging the init;
 # Set DEBUG to '1' to enable explicit pauses; '2' enables verbose script exec;
 # and '4' dumps you into a debug shell right before the switch_root:
@@ -176,6 +179,11 @@ for ARG in $(cat /proc/cmdline); do
     nop)
       VIRGIN=1
     ;;
+    nop=*)
+      if [ "$(echo $ARG | cut -f2 -d=)" = "wipe" ]; then
+        WIPE_PERSISTENCE=1
+      fi
+    ;;
     persistence=*)
       PERSISTENCE=$(echo $ARG | cut -f2 -d=)
     ;;
@@ -670,6 +678,10 @@ if [ "$RESCUE" = "" ]; then
       # Try a write... just to be dead sure:
       if touch /mnt/media/${PERSISTENCE}/.rwtest 2>/dev/null && rm /mnt/media/${PERSISTENCE}/.rwtest 2>/dev/null ; then
         # Writable media and we are allowed to write to it.
+        if [ "$WIPE_PERSISTENCE" = "1" ]; then
+          echo "${MARKER}:  Wiping existing persistent data in '/${PERSISTENCE}'."
+          find /mnt/media/${PERSISTENCE}/ -mindepth 1 -exec rm -rf {} \; 2>/dev/null
+        fi
         echo "${MARKER}:  Writing persistent changes to media directory '/${PERSISTENCE}'."
         UPPERDIR=/mnt/media/${PERSISTENCE}
         OVLWORK=/mnt/media/.ovlwork
@@ -700,6 +712,10 @@ if [ "$RESCUE" = "" ]; then
         echo "${MARKER}:  Failed to mount persistence file '/${PERSISTENCE}.img'."
         echo "${MARKER}:  Falling back to RAM."
       else
+        if [ "$WIPE_PERSISTENCE" = "1" ]; then
+          echo "${MARKER}:  Wiping existing persistent data in '/${PERSISTENCE}.img'."
+          find /mnt/live/${prdir}/${PERSISTENCE}/ -mindepth 1 -exec rm -rf {} \; 2>/dev/null
+        fi
         echo "${MARKER}:  Writing persistent changes to file '/${PERSISTENCE}.img'."
         UPPERDIR=/mnt/live/${prdir}/${PERSISTENCE}
         OVLWORK=/mnt/live/${prdir}/.ovlwork