From 05e2b4b7564ba517aed3e1e714235312df6349d9 Mon Sep 17 00:00:00 2001
From: Eric Hameleers <alien@slackware.com>
Date: Fri, 15 Jun 2018 13:06:32 +0200
Subject: Add support for on-disk OS configuration file

The configuration file must be in the liveslak main directory ('/liveslak'
by default) and be called 'DISTRO_os.cfg' where DISTRO is the lower-case
name of the distro ('slackware' by default).

The following variables can be defined in the configuration file,
one per line, in the format VAR=value:
BLACKLIST, INIT, KEYMAP, LIVE_HOSTNAME, LOAD, LOCALE, LUKSVOL, NOLOAD,
RUNLEVEL, TWEAKS, TZ, XKB.

Since the configuration file is sourced by the live init script, it is OK
to have comments in it that are prefixed with '#'.
---
 EFI/BOOT/help.txt |  5 +++++
 README.txt        |  5 +++++
 liveinit.tpl      | 38 +++++++++++++++++++++++++++++++++++++-
 syslinux/f3.txt   |  5 +++++
 4 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/EFI/BOOT/help.txt b/EFI/BOOT/help.txt
index ed13122..dbfb5b2 100644
--- a/EFI/BOOT/help.txt
+++ b/EFI/BOOT/help.txt
@@ -66,6 +66,11 @@ swap => Allow the Live OS to activate all swap partitions on
 
 === Media tweaks ===
 
+cfg=[skip|write] =>
+  Specify 'skip' to skip disk-based configuration file containing
+  OS parameters; or specify 'write' to write current OS parameters
+  to disk.
+
 hostname=your_custom_hostname[,qualifier] =>
   Specify a custom hostname.  A qualifier 'fixed' can be appended
   to prohibit hostname modification in  case of network boot.
diff --git a/README.txt b/README.txt
index c6c6e3b..d8a4128 100644
--- a/README.txt
+++ b/README.txt
@@ -330,6 +330,11 @@ swap => Allow the Live OS to activate all swap partitions on
 
 === Media tweaks ===
 
+cfg=[skip|write] =>
+  Specify 'skip' to skip disk-based configuration file containing
+  OS parameters; or specify 'write' to write current OS parameters
+  to disk.
+
 hostname=your_custom_hostname[,qualifier] =>
   Specify a custom hostname.  A qualifier 'fixed' can be appended
   to prohibit hostname modification in  case of network boot.
diff --git a/liveinit.tpl b/liveinit.tpl
index 5cddd02..da1b4ff 100755
--- a/liveinit.tpl
+++ b/liveinit.tpl
@@ -2,7 +2,7 @@
 #
 # Copyright 2004  Slackware Linux, Inc., Concord, CA, USA
 # Copyright 2007, 2008, 2009, 2010, 2012  Patrick J. Volkerding, Sebeka, MN, USA
-# Copyright 2015, 2016, 2017  Eric Hameleers, Eindhoven, NL
+# Copyright 2015, 2016, 2017, 2018  Eric Hameleers, Eindhoven, NL
 # All rights reserved.
 #
 # Redistribution and use of this script, with or without modification, is
@@ -49,6 +49,9 @@ LIVEUID="@LIVEUID@"
 LIVEMEDIA=""
 LIVEPATH=""
 
+DISTROCFG="@DISTRO@_os.cfg"
+CFGACTION=""
+
 # By default, let the media determine if we can write persistent changes:
 # However, if we define TORAM=1, we will also set VIRGIN=1 since we want
 # to avoid anything that writes to disk after we copy the OS to RAM.
@@ -185,6 +188,10 @@ for ARG in $(cat /proc/cmdline); do
       # nic=<driver>:<interface>:<dhcp|static>[:ipaddr:netmask[:gateway]]
       ENET=$(echo $ARG | cut -f2 -d=)
     ;;
+    cfg=*)
+      CFGACTION=$(echo $ARG | cut -f2 -d=)
+      if [ "${CFGACTION}" = "skip" ]; then DISTROCFG="" ; fi
+    ;;
     noload=*)
       NOLOAD=$(echo $ARG | cut -f2 -d=)
     ;;
@@ -676,6 +683,35 @@ if [ "$RESCUE" = "" ]; then
 
   debugit
 
+  # liveslak can optionally load a OS config file "@DISTRO@_os.cfg"
+  # which contains "VARIABLE=value" lines, where VARIABLE is one of
+  # the following variables that are used below in the live init script:
+  #   BLACKLIST, INIT, KEYMAP, LIVE_HOSTNAME, LOAD, LOCALE, LUKSVOL,
+  #   NOLOAD, RUNLEVEL, TWEAKS, TZ, XKB. 
+  if [ -z "$CFGACTION" ]; then
+    # Read OS configuration from disk file if present
+    # (prevent this by adding 'cfg=skip' to the boot commandline).
+    if [ -f "/mnt/media/${LIVEMAIN}/${DISTROCFG}" ]; then
+      source /mnt/media/${LIVEMAIN}/${DISTROCFG}
+    fi
+  elif [ "$CFGACTION" = "write" ]; then
+    # Write liveslak OS parameters to disk:
+    echo > /mnt/media/${LIVEMAIN}/${DISTROCFG} 2>/dev/null
+    if [ $? -ne 0 ]; then
+      echo "${MARKER}:  Live media read-only, cannot write config file."
+    else
+      echo "${MARKER}:  Writing config to /${LIVEMAIN}/${DISTROCFG}"
+      for LIVEPARM in \
+        BLACKLIST INIT KEYMAP LIVE_HOSTNAME LOAD LOCALE LUKSVOL \
+        NOLOAD RUNLEVEL TWEAKS TZ XKB ;
+      do
+        if [ -n "$(eval echo \$$LIVEPARM)" ]; then
+          echo $LIVEPARM=$(eval echo \$$LIVEPARM) >> /mnt/media/${LIVEMAIN}/${DISTROCFG}
+        fi 
+      done
+    fi
+  fi
+
   # Start assembling our live system components below /mnt/live :
   mkdir /mnt/live
 
diff --git a/syslinux/f3.txt b/syslinux/f3.txt
index 6cce00d..a5400f5 100644
--- a/syslinux/f3.txt
+++ b/syslinux/f3.txt
@@ -4,6 +4,11 @@ To boot with default values just press ENTER.
 
 === Media tweaks ===
 
+cfg=[skip|write] =>
+  Specify 'skip' to skip disk-based configuration file containing
+  OS parameters; or specify 'write' to write current OS parameters
+  to disk.
+
 hostname=your_custom_hostname[,qualifier] =>
   Specify a custom hostname.  A qualifier 'fixed' can be appended
   to prohibit hostname modification in  case of network boot.
-- 
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