Rework munge_fstab to shrink and clarify code.

Collect all tests that cause a line to be skipped into one test by
using ksh string pattern features instead of case statements.

Simply sed expressions by not worrying about extra commas in the
options field (they're ignored during mount) and assuming 'rw',
'noauto', 'xx' do not appear as substrings in any valid option.

Leave out fs_freq and fs_passno fields as unnecessary during
install/upgrade.

Eliminate special test for '/' mount point and simply strip any
trailing slash from all mount points.

Kicked off my wifried@'s 'xx'/altroot change, and ok'ed in various
incarnations by wilfried@ deraadt@ millert@.

1 files changed, 29 insertions, 35 deletions

diff --git a/distrib/miniroot/install.sub b/distrib/miniroot/install.sub
index 2afdc6a7041..6138bd4839a 100644
--- a/distrib/miniroot/install.sub
+++ b/distrib/miniroot/install.sub
@@ -1,4 +1,4 @@
-#	$OpenBSD: install.sub,v 1.296 2003/04/23 12:06:55 wilfried Exp $
+#	$OpenBSD: install.sub,v 1.297 2003/04/30 23:56:30 krw Exp $
 #	$NetBSD: install.sub,v 1.5.2.8 1996/09/02 23:25:02 pk Exp $
 #
 # Copyright (c) 1997-2003 Todd Miller, Theo de Raadt, Ken Westerback
@@ -1513,52 +1513,46 @@ __EOT
 	done
 }
 
-# Create a /etc/fstab from /tmp/fstab. Ensure /etc/fstab
-#	1) contains only filesystems we can mount
-#	2) contains no altroot filesystem
-#	3) contains only filesystems without the 'noauto' option
-#	4) contains no 'softdep' options
-#	5) mounts all filesystems relative to /mnt
+# Create a skeletal but useful /etc/fstab from /tmp/fstab by stripping all
+# comment lines and dropping all filesystems which
+#
+#       1) can't be mounted (no mount_* command is found),
+#	2) have 'xx' in the option field (usually /altroot),
+#	3) have 'noauto' in the option field,
+#	4) are nfs (since name resolution may not be present).
+#
+# In addition,
+#
+#	1) delete 'softdep' options (no soft updates in ramdisk kernels),
+#	2) mount non-ffs filesystems read only,
+#	3) prepend '/mnt' to all mount points,
+#	4) delete any trailing '/' from the mount point (e.g. root),
+#	5) leave out fs_freq and fs_passno fields.
 #
 # If no /etc/fstab is created, do not proceed with install/upgrade.
 munge_fstab() {
 	local _dev _mp _fstype _opt _rest
 
 	while read _dev _mp _fstype _opt _rest; do
-		# Skip comment lines.
-		case $_dev in
-		\#*)	continue ;;
-		esac
-
-		# Skip noauto and altroot filesystems.
-		case $_opt in
-		*noauto*|*xx*) continue ;;
-		esac
-
-		# Skip filesystems we can't mount.
-		[ -f "/sbin/mount_${_fstype}" ] || continue
-
-		# Skip nfs filesystems because all name
-		# resolutions (e.g. yp) are not available
-		# and success is not guaranteed. The user
-		# will have to mount nfs filesystems manually.
-		[ "$_fstype" != "nfs" ] || continue
+		# Drop irrelevant lines and filesystems.
+		[[ $_dev == \#* || \
+		    $_fstype == nfs || \
+		    ! -f /sbin/mount_$_fstype || \
+		    $_opt == *noauto* || \
+		    $_opt == *xx* ]] && continue
 
 		# Remove any softdep options, as soft updates are not
 		# available in the ramdisk kernels.
-		_opt="$(echo ${_opt} | \
-			sed -e 's/^softdep$//; s/^softdep,//; s/,softdep,/,/; s/,softdep$//;')"
-
-		# Mount non-ffs filesystems read-only
-		[ "$_fstype" = "ffs" ] || \
-			_opt="$(echo ${_opt} | \
-				sed -e 's/^rw$/ro/; s/^rw,/ro,/; s/,rw,/,ro,/; s/,rw$/,ro/')"
+		_opt=$(echo $_opt | sed -e 's/softdep//')
 
-		# Avoid '/mnt/' in root fs entry in munged fstab
-		[ "$_mp" = "/" ] && _mp=
+		# Mount non-ffs filesystems read only.
+		[[ $_fstype == ffs ]] || _opt=$(echo $_opt | sed -e 's/rw/ro/')
 
 		# Write fs entry in fstab.
-		echo $_dev /mnt$_mp $_fstype $_opt $_rest
+		# 1) prepend '/mnt' to the mount point.
+		# 2) remove a trailing '/' from the mount point (e.g. root).
+		# 3) leave out fs_freq and fs_passno fields (i.e. $_rest).
+		echo $_dev /mnt${_mp%/} $_fstype $_opt
 
 	done < /tmp/fstab > /etc/fstab