-d option for fshalt

[Alex Musolino <alex@musolino.id.au>]

Hi all,

I've added support for a -d option in fshalt(8) that triggers a dump
of the local filesystem before halting.  I've found it useful in my
current situation where my 9front machine spends most of its time
powered off.

Any objections to the following?

diff -r 8006152d13d2 rc/bin/fshalt
--- a/rc/bin/fshalt	Tue Apr 28 20:51:19 2020 -0700
+++ b/rc/bin/fshalt	Tue Jun 02 14:03:03 2020 +0930
@@ -1,16 +1,20 @@
 #!/bin/rc
-# fshalt [-r] - sync (flush) and, if possible, halt all file servers
-#	and optionally reboot
 rfork en
+dump=no
 reboot=no
 scram=no
-switch ($#*) {
-case 0
-case 1
-	reboot=yes
-case *
-	echo usage: $0 '[-r]' >[1=2]
-	exit usage
+
+while (~ $1 -*) {
+	switch ($1) {
+	case -d
+		dump=yes
+	case -r
+		reboot=yes
+	case *
+		echo usage: $0 '[-r]' >[1=2]
+		exit usage
+	}
+	shift
 }
 
 path=(/bin)
@@ -53,6 +57,13 @@
 # when it's no longer accessible
 fn x {
 	echo
+	echo -n dumping...
+	if (~ $dump yes) {
+		for (i in $c $h)
+			echo dump >>$i
+	}
+
+	echo
 	echo -n halting...
 	for (i in $c $h)
 		echo halt >>$i
diff -r 8006152d13d2 sys/man/8/fshalt
--- a/sys/man/8/fshalt	Tue Apr 28 20:51:19 2020 -0700
+++ b/sys/man/8/fshalt	Tue Jun 02 14:03:03 2020 +0930
@@ -4,6 +4,8 @@
 .SH SYNOPSIS
 .B fshalt
 [
+.B -d
+] [
 .B -r
 ]
 .br
@@ -20,13 +22,15 @@
 and
 .IR hjfs (4)
 servers.
-If given
-.BR -r ,
-.I fshalt
-will then reboot the machine.
-Else it will invoke
+The
+.BR -d
+option causes a dump command to be issued to the local filesystem
+before the sync and halt commands.  Once any filesystems have been
+halted,
 .I scram
-to shut down the machine.
+will be invoked to shut down the machine, unless the
+.BR -r
+option is specified, in which case the machine is instead rebooted.
 The halting and rebooting is done by copying all necessary
 commands into a
 .IR ramfs (4)