o Implement the stop_boot subroutine [1]. This subroutine can be used by

  scripts in rc.d to stop rc(8) from booting into multi-user mode when
  a critical or severe error condition is encountered.

o Modify scripts in etc/rc.d that already implemented this functionality
  independently.

o Document it.

[1] - This subroutine was implemented in FreeBSD in rc.d/fsck. I moved it
      to rc.subr(8). Our version differs slightly in that it takes an
      optional argument to stop the boot even if "autoboot" is not set.

Obtained from: NetBSD
MFC after: 2 weeks

2 files changed, 24 insertions, 12 deletions

diff --git a/share/man/man8/rc.8 b/share/man/man8/rc.8
index 4f1f1ce..7d3cfe5 100644
--- a/share/man/man8/rc.8
+++ b/share/man/man8/rc.8
@@ -35,7 +35,7 @@
 .\"     @(#)rc.8	8.2 (Berkeley) 12/11/93
 .\" $FreeBSD$
 .\"
-.Dd December 19, 2005
+.Dd May 18, 2007
 .Dt RC 8
 .Os
 .Sh NAME
@@ -249,16 +249,11 @@ Extreme care must be taken in using this, as the startup sequence will
 terminate if the script does.
 .It Pa bar
 Scripts that are sourced in a subshell.
-These can stop the boot if necessary with the following shell
-commands:
-.Bd -literal -offset indent
-if [ "$autoboot" = yes ]; then
-	kill -TERM $$
-fi
-exit 1
-.Ed
-.Pp
-Note that this should be used extremely sparingly!
+The boot does not stop if such a script terminates with a non-zero status,
+but a script can stop the boot if necessary by invoking the
+.Fn stop_boot
+function (from
+.Xr rc.subr 8 ).
 .El
 .Pp
 Each script should contain
diff --git a/share/man/man8/rc.subr.8 b/share/man/man8/rc.subr.8
index abebb76..682acd9 100644
--- a/share/man/man8/rc.subr.8
+++ b/share/man/man8/rc.subr.8
@@ -36,7 +36,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd December 27, 2006
+.Dd May 18, 2007
 .Dt RC.SUBR 8
 .Os
 .Sh NAME
@@ -833,6 +833,23 @@ otherwise source
 .Ar file
 into the current shell.
 .El
+.It Ic stop_boot Op Ar always
+Prevent booting to multiuser mode.
+If the
+.Sy autoboot
+variable is
+.Sq yes ,
+or
+.Ar always
+is
+.Sq true ,
+then a
+.Sy SIGTERM
+signal is sent to the parent
+process (which is assumed to be
+.Xr rc 8 ).
+Otherwise, the shell exits with status
+.Li 1 .
 .It Ic set_rcvar Op Ar base
 Set the variable name required to start a service.
 In