add the option to picobsd to copy files from the host filesystem

without root privs. This is done, among other things, replacing
the absolute paths in the symlinks with relative paths, so we
do not need to do a chroot to follow them.

Still need to update the manpage.

MFC after:	3 days

release/picobsd/build/picobsd

@@ -284,6 +284,9 @@ build_image() {
     if [ -f ${MY_TREE}/config ] ; then
 	. ${MY_TREE}/config
     fi
+    if [ -f ${o_additional_config} ] ; then
+	. ${o_additional_config}
+    fi
 
     # location of the object directory
     PICO_OBJ=${l_objtree}/picobsd/${THETYPE}
@@ -529,6 +532,32 @@ populate_floppy_fs() {		# OK
     ) || true
 }
 
+# Copy the specified files to the destination filesystem.
+# Each file is specified as a pair "src dst", dst is assumed to be
+# a directory (and created with mkdir -p) if it has a trailing /
+# Be careful to escape metacharacters.
+# You can use ${CROSS} to point to the root of the cross build
+# (remember that it might be incomplete)
+
+do_copyfiles() {	# rootdir varname
+	log Copy files to $1
+	local root=$1
+	local srcs dst
+	local CROSS=${_SHLIBDIRPREFIX}
+	eval set "\${${2}}"
+        srcs=""
+	for dst in $* ; do
+		[ x"$srcs" = x ] && srcs=$dst && continue
+		eval srcs="$srcs"	# expand wildcard and vars
+		case x"$dst" in
+		*/ )	mkdir -p ${root}/${dst} ;;
+		# * )	mkdir -p `dirname ${root}/${dst}` ;;
+		esac
+		cp -p ${srcs} ${root}/${dst} || true
+		srcs=""
+        done
+}
+
 # Populate the memory filesystem with binaries and non-variable
 # configuration files.
 # First do an mtree pass, then create directory links and device entries,
@@ -537,7 +566,7 @@ populate_floppy_fs() {		# OK
 # Finally, if required, make a copy of the floppy.tree onto /fd
 
 populate_mfs_tree() {
-    local a dst MFS_TREE
+    local i j a dst MFS_TREE
 
     log "populate_mfs_tree()"
     dst=${BUILDDIR}/mfs.tree
@@ -552,12 +581,15 @@ populate_mfs_tree() {
     log "Running mtree using $a..."
     mtree -deU -f $a -p ${dst} > /dev/null || fail $? mtree
 
-    # XXX create links
+    # Create symlinks using relative pathnames, so it is possible
+    # to follow them also when building the image.
+    # Note that names in STAND_LINKS should not have a leading /
     for i in ${STAND_LINKS}; do
-	ln -s /stand ${dst}/$i
+	j=`echo $i | sed -E 's:^[^/]+::;s:/[^/]+:../:g'`
+	ln -s ${j}stand ${dst}/$i
     done
-    ln -s /dev/null ${dst}/var/run/log
-    ln -s /etc/termcap ${dst}/usr/share/misc/termcap
+    ln -s ../../dev/null ${dst}/var/run/log
+    ln -s ../../../etc/termcap ${dst}/usr/share/misc/termcap
 
     ### now build the crunched binaries ###
     (
@@ -629,6 +661,13 @@ populate_mfs_tree() {
 	(cd ${dst}; chown -R root . )
     fi
 
+    if [ -n "${copy_files}" ] ; then
+	do_copyfiles ${dst} copy_files
+    fi
+
+    # The 'import_files' mechanism is deprecated, as it requires
+    # root permissions to follow the symlinks, and also does
+    # not let you rename the entries.
     if [ -n "${import_files}" ] ; then
 	log "importing ${import_files} into mfs"
 	# We do it in a chroot environment on the target so
@@ -641,6 +680,7 @@ populate_mfs_tree() {
 	rm -rf ${dst}/rescue
     fi
 
+    # final step -- build the mfs image
     (cd ${BUILDDIR}
 	# override the owner
 	echo "/set uid=0 gid=0" > mtree.out
@@ -916,6 +956,11 @@ while [ true ]; do
 	generate_iso="YES"
 	;;
 
+    --cfg) # read additional config from this file
+	o_additional_config=`realpath $2`
+	shift
+	;;
+
     *)
 	break
 	;;