nanobsd: Avoid read-only file system warnings

The default setting of some loader or rc variables generate warnings
because the file system is read-only:

Set the following options to avoid printing these warnings:

/boot/defaults/loader.conf:

- hostuuid_load="NO" to disable loading /etc/hostid early at boot time
- entropy_cache_load="NO" to disable loading cached entropy at boot time
- kern.random.initial_seeding.disable_bypass_warnings="1" to disable
  logging a warning if the 'bypass_before_seeding' knob is enabled
  (enabled by default) and a request is submitted prior to initial
  seeding

/etc/defaults/rc.conf:

- kldxref_enable="NO" to disable building linker.hints files with
  kldxref(8)
- entropy_boot_file="NO" to disable very early (used at early boot-time)
  entropy caching through reboots
- entropy_dir="NO" to disable caching entropy via cron

While here, move rc.conf options before sourcing vendor.conf, so they
can be overridden.

PR:		277601
Reviewed by:	imp
Approved by:	emaste (mentor)
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D47502

(cherry picked from commit e5579f98c02ff64b0c305f6731c3557ba69c2d25)

1 files changed, 33 insertions, 4 deletions

diff --git a/tools/tools/nanobsd/defaults.sh b/tools/tools/nanobsd/defaults.sh
index d5d357d9ad19..bb1e96b911e5 100755
--- a/tools/tools/nanobsd/defaults.sh
+++ b/tools/tools/nanobsd/defaults.sh
@@ -570,13 +570,42 @@ setup_nanobsd_etc ( ) (
 	# create diskless marker file
 	touch etc/diskless
 
+	[ -n "${NANO_NOPRIV_BUILD}" ] && chmod 666 boot/defaults/loader.conf
+	{
+		echo
+		echo '###  NanoBSD configuration  ##################################'
+		echo 'hostuuid_load="NO"'
+		echo 'entropy_cache_load="NO"		# Disable loading cached entropy at boot time.'
+		echo 'kern.random.initial_seeding.disable_bypass_warnings="1"	# Do not log a warning'
+		echo "				# if the 'bypass_before_seeding' knob is enabled"
+		echo "				# and a request is submitted prior to initial"
+		echo "				# seeding."
+	} >> boot/defaults/loader.conf
+	[ -n "${NANO_NOPRIV_BUILD}" ] && chmod 444 boot/defaults/loader.conf
+
 	[ -n "${NANO_NOPRIV_BUILD}" ] && chmod 666 etc/defaults/rc.conf
+	if ! ed -s etc/defaults/rc.conf <<\EOF
+/^### Define source_rc_confs, the mechanism used by \/etc\/rc\.\* ##$/i
+###  NanoBSD options  ########################################
+##############################################################
 
-	# Make root filesystem R/O by default
-	echo "root_rw_mount=NO" >> etc/defaults/rc.conf
-	# Disable entropy file, since / is read-only /var/db/entropy should be enough?
-	echo "entropy_file=NO" >> etc/defaults/rc.conf
+kldxref_enable="NO"	# Disable building linker.hints files with kldxref(8).
+root_rw_mount="NO"	# Inhibit remounting root read-write.
+entropy_boot_file="NO"	# Disable very early (used at early boot time)
+			# entropy caching through reboots.
+entropy_file="NO"	# Disable late (used when going multi-user)
+			# entropy through reboots.
+entropy_dir="NO"	# Disable caching entropy via cron.
 
+##############################################################
+.
+w
+q
+EOF
+	then
+		echo "Regular expression pattern not found"
+		exit 2
+	fi
 	[ -n "${NANO_NOPRIV_BUILD}" ] && chmod 444 etc/defaults/rc.conf
 
 	# save config file for scripts