atari sysinst.fs overflow again

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

http://mail-index.netbsd.org/source-changes/2017/11/15/msg089733.html
> Module Name:	src
> Committed By:	tsutsui
> Date:		Wed Nov 15 16:37:00 UTC 2017
> 
> Modified Files:
> 	src/distrib/atari/floppies/install: list
> 
> Log Message:
> Put back /bin/cp and /sbin/sysctl to installation binaries.
> 
> - cp(1) is explicitly required by sysinst(8), cp_to_target() in
>   src/usr.sbin/sysinst/target.c, to copy bootloader to targetroot
> - sysctl(8) is required by src/distrib/atari/floppies/common/dot.profile
>   to detect the root device (fd or md)
> 
> This might cause floppy overflow on HEAD again, but works on 8.0_BETA.
> 
> Should be pulled up to netbsd-8.

As I was afraid, this change causes -current sysinst.fs overflow again:

https://releng.netbsd.org/builds/HEAD/201711180030Z/atari.build.failed
---
Calculated size of `sysinst.fs.tmp': 1474560 bytes, 320 inodes
Extent size set to 4096
sysinst.fs.tmp: 1.4MB (2880 sectors) block size 4096, fragment size 512
	using 1 cylinder groups of 1.41MB, 360 blks, 384 inodes.
super-block backups (for fsck -b #) at:
 32,nbmakefs: Writing inode 306 (work/./usr/mdec/milan/bootxx), bytes 4096 + 2560: No space left on device
Populating `sysinst.fs.tmp'
---

Removing /bin/df (MAKEDEV(8) has no longer required it) is not enough,
so I'm trying to remove sysctl(8) next since it's used only to get
root device, as noted in the commit log.

With @s_mitu's help, I've managed to get root device from dmesg output
with sed(1):

---
Index: floppies/common/dot.profile
===================================================================
RCS file: /cvsroot/src/distrib/atari/floppies/common/dot.profile,v
retrieving revision 1.6
diff -u -p -d -r1.6 dot.profile
--- floppies/common/dot.profile	15 Nov 2017 16:19:19 -0000	1.6
+++ floppies/common/dot.profile	18 Nov 2017 16:38:39 -0000
@@ -49,8 +49,8 @@ umask 022
 mount_gemdos() mount_msdos -G "$@"
 
 makerootwritable() {
-	# note, only handles up to partition 'j'
-	rootdev=/dev/$(sysctl -n kern.root_device)$(sysctl -n kern.root_partition | sed y/0123456789/abcdefghij/)
+	# check most recent 'root on [dev] dumps on [dev]' line in dmesg
+	rootdev=/dev/$(dmesg | sed -n '/^root on/h;${;g;s/^root on //g;s/ dumps.*//g;p;}')
 	if ! mount -u $rootdev / ; then
 	    echo "Unable to mount $rootdev read-write"
 	    exit 1
Index: floppies/install/list
===================================================================
RCS file: /cvsroot/src/distrib/atari/floppies/install/list,v
retrieving revision 1.21
diff -u -p -d -r1.21 list
--- floppies/install/list	15 Nov 2017 16:37:00 -0000	1.21
+++ floppies/install/list	18 Nov 2017 16:38:39 -0000
@@ -31,7 +31,7 @@ PROG	sbin/newfs	sbin/mount_mfs
 PROG	sbin/ping
 PROG	sbin/reboot	sbin/halt
 PROG	sbin/route
-PROG	sbin/sysctl
+#PROG	sbin/sysctl
 PROG	sbin/umount
 
 PROG	usr/bin/ftp

---

I would like to have review comments from script guru before commit.

Thanks,

---
Izumi Tsutsui