Redirect stdin from /dev/null when starting a jail:

  At least in RELENG_7 this fixes some start problems for some programs
  from the ports. It is also more correct, as a jail shall not expect
  input (interactivity) from the jail-host.

Revert the current behavior of starting jails in the background and
make it optional only for the start of jails (jail_parallell_start=YES
in rc.conf):
 - The stop can not be done in the background, the system needs to wait
   until everything is stopped correctly before it can reboot or power
   down.
 - The start should not be done in parallel by default, this not only
   breaks POLA for people comming from RELENG_x, it may also break a
   dependency chain with other scripts in the jail-host, which need to
   do some stuff after the jails are up and running (e.g. hardlinking
   a mysql socket from one jail into another one).

Discussed on:	freebsd-jails@

2 files changed, 19 insertions, 2 deletions

diff --git a/etc/defaults/rc.conf b/etc/defaults/rc.conf
index 35b3a7b..dfdf08f 100644
--- a/etc/defaults/rc.conf
+++ b/etc/defaults/rc.conf
@@ -637,6 +637,7 @@ mixer_enable="YES"	# Run the sound mixer.
 ### Jail Configuration #######################################
 ##############################################################
 jail_enable="NO"	# Set to NO to disable starting of any jails
+jail_parallel_start="NO"	# Start jails in the background
 jail_list=""		# Space separated list of names of jails
 jail_set_hostname_allow="YES" # Allow root user in a jail to change its hostname
 jail_socket_unixiproute_only="YES" # Route only TCP/IP within a jail
diff --git a/etc/rc.d/jail b/etc/rc.d/jail
index 084acb7..76342cf 100755
--- a/etc/rc.d/jail
+++ b/etc/rc.d/jail
@@ -636,7 +636,8 @@ jail_start()
 		done
 
 		eval ${_setfib} jail ${_flags} -i ${_rootdir} ${_hostname} \
-			\"${_addrl}\" ${_exec_start} > ${_tmp_jail} 2>&1
+			\"${_addrl}\" ${_exec_start} > ${_tmp_jail} 2>&1 \
+			</dev/null
 
 		if [ "$?" -eq 0 ] ; then
 			_jail_id=$(head -1 ${_tmp_jail})
@@ -728,4 +729,19 @@ fi
 if [ -n "$*" ]; then
 	jail_list="$*"
 fi
-run_rc_command "${cmd}" &
+
+# Only allow the parallel start of jails, other commands are not
+# safe to execute in parallel.
+case "${cmd}" in
+*start)
+	;;
+*)
+	jail_parallel_start=NO
+esac
+
+if checkyesno jail_parallel_start; then
+	run_rc_command "${cmd}" &
+else
+	run_rc_command "${cmd}"
+fi
+