From 889791af8eb9cb4b19cd96d2891836e4205473f0 Mon Sep 17 00:00:00 2001
From: eugen <eugen@FreeBSD.org>
Date: Mon, 19 Nov 2018 06:37:38 +0000
Subject: [PATCH] MFC r339465: rc.initdiskless: add support for auxiliary
 NVRAM.

  Currently, rc.inidiskless assumes that local system configuration
  changes are kept in some mountable file system. For example,
  nanobsd uses dedicated partition mounted as /cfg for this.

  However, small embedded devices like MIPS routers may have no enough flash
  space to keep full-blown file system but have only one or couple
  small flash blocks to keep persistent local configuration overrides.

  This change extends rc.initdiskless and introduces ability to run auxiliary
  command /conf/T/M/extract that is supposed to extract configuration overrides
  from such local storage.

  For example, the command /conf/default/etc/extract may contain something like:

  cd "$1" && bsdcpio --quiet -idu < /dev/map/cfg

  bsdcpio command extracts compressed archive from the storage to /etc
  assuming the storage is exposed by the kernel as /dev/map/cfg to userland.

PR:		204215
---
 etc/rc.initdiskless | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/etc/rc.initdiskless b/etc/rc.initdiskless
index 3e9c2c70099..812c8daba86 100644
--- a/etc/rc.initdiskless
+++ b/etc/rc.initdiskless
@@ -111,6 +111,15 @@
 #		created for /SUBDIR if necessary). The presence of this file
 #		prevents the copy from /conf/T/SUBDIR/
 #
+# /conf/T/M/extract
+#		This is alternative to SUBDIR.cpio.gz and remount.
+#		Similar to remount case, a memory filesystem is created
+#		for /M and initialized from a template but no mounting
+#		performed. Instead, this file is run passing /M as singe
+#		argument. It is expected to extract template override to /M
+#		using auxiliary storage found in some embedded systems
+#		having NVRAM too small to hold mountable file system.
+#
 # /conf/T/SUBDIR.remove
 #		The list of paths contained in the file are rm -rf'd
 #		relative to /SUBDIR.
@@ -343,8 +352,8 @@ done
 
 # - Create all required MFS filesystems and populate them from
 #   our templates.  Support both a direct template and a dir.cpio.gz
-#   archive.  Support dir.remove files containing a list of relative
-#   paths to remove.
+#   archive. Support for auxiliary NVRAM. Support dir.remove files containing
+#   a list of relative paths to remove.
 #
 # The dir.cpio.gz form is there to make the copy process more efficient,
 # so if the cpio archive is present, it prevents the files from dir/
@@ -367,6 +376,15 @@ for i in ${templates} ; do
 	    (cd / ; /rescue/tar -xpf $j)
 	fi
     done
+    for j in /conf/$i/*/extract ; do
+	if [ -x $j ]; then
+	    subdir=${j%*/extract}
+	    subdir=${subdir##*/}
+	    create_md $subdir
+	    echo "Loading /$subdir using auxiliary command $j"
+	    $j /$subdir
+	fi
+    done
     for j in /conf/$i/*.remove ; do
 	subdir=${j%*.remove}
 	subdir=${subdir##*/}
-- 
2.45.0