Use the new command file feature of ddb(8) to support setting ddb(4)

scripts at boot.  This is currently disabled by default. /etc/ddb.conf
contains some potentially reasonable default scripts.

PR:		conf/119995
Submitted by:	Scot Hetzel <swhetzel at gmail dot com> (Earlier version)
X-MFC after:	textdumps

etc/Makefile

@@ -9,7 +9,7 @@ SUBDIR=	sendmail
 
 BIN1=	amd.map apmd.conf auth.conf \
 	crontab csh.cshrc csh.login csh.logout devd.conf devfs.conf \
-	dhclient.conf disktab fbtab freebsd-update.conf \
+	ddb.conf dhclient.conf disktab fbtab freebsd-update.conf \
 	ftpusers gettytab group \
 	hosts hosts.allow hosts.equiv hosts.lpd \
 	inetd.conf libalias.conf login.access login.conf mac.conf motd \

etc/ddb.conf

@@ -0,0 +1,15 @@
+# $FreeBSD$
+#
+#  This file is read when going to multi-user and its contents piped thru
+#  ``ddb'' to define debugging scripts.
+#
+# see ``man 4 ddb'' and ``man 8 ddb'' for details.
+#
+
+script lockinfo=show locks; show alllocks; show lockedvnods
+
+# kdb.enter.panic	panic(9) was called.
+script kdb.enter.panic=textdump set; capture on; run lockinfo; show pcpu; bt; ps; alltrace; capture off; call doadump; reset
+
+# kdb.enter.witness	witness(4) detected a locking error.
+script kdb.enter.witness=run lockinfo

etc/defaults/rc.conf

@@ -33,6 +33,8 @@ swapfile="NO"		# Set to name of swapfile if aux swapfile desired.
 apm_enable="NO"		# Set to YES to enable APM BIOS functions (or NO).
 apmd_enable="NO"	# Run apmd to handle APM event from userland.
 apmd_flags=""		# Flags to apmd (if enabled).
+ddb_enable="NO"		# Set to YES to load ddb scripts at boot.
+ddb_config="/etc/ddb.conf"	# ddb(8) config file.
 devd_enable="YES" 	# Run devd, to trigger programs on device tree changes.
 devd_flags=""		# Additional flags for devd(8).
 kldxref_enable="NO"	# Build linker.hints files with kldxref(8).

etc/rc.d/Makefile

@@ -7,7 +7,7 @@ FILES=	DAEMON FILESYSTEMS LOGIN NETWORKING SERVERS \
 	apm apmd archdep atm1 atm2 atm3 auditd auto_linklocal \
 	bgfsck bluetooth bootparams bridge bsnmpd bthidd \
 	ccd cleanvar cleartmp cron \
-	devd devfs dhclient \
+	ddb devd devfs dhclient \
 	dmesg dumpon \
 	early.sh encswap \
 	fsck ftp-proxy ftpd \

etc/rc.d/ddb

@@ -0,0 +1,32 @@
+#!/bin/sh
+#
+# $FreeBSD$
+#
+
+# PROVIDE: ddb
+# REQUIRE: dumpon
+# BEFORE: disks savecore initrandom
+# KEYWORD: nojail
+
+. /etc/rc.subr
+
+name="ddb"
+rcvar=`set_rcvar`
+command="/sbin/${name}"
+start_precmd="ddb_prestart"
+stop_cmd=":"
+
+ddb_prestart()
+{
+	# Silently exit if ddb is not enabled
+	if [ -z "`sysctl -Nq debug.ddb.scripting.scripts`" ]; then
+		return 1
+	fi
+}
+
+load_rc_config $name
+
+required_files="${ddb_config}"
+command_args="${ddb_config}"
+
+run_rc_command "$1"

share/man/man5/rc.conf.5

@@ -164,6 +164,19 @@ daemon.
 Run
 .Xr devd 8
 to handle device added, removed or unknown events from the kernel.
+.It Va ddb_enable
+.Pq Vt bool
+Run
+.Xr ddb 8
+to install 
+.Xr ddb 4
+scripts at boot time.
+.It Va ddb_config
+.Pq Vt str
+Configuration file for
+.Xr ddb 8 .
+Default
+.Pa /etc/ddb.conf .
 .It Va kldxref_enable
 .Pq Vt bool
 Set to