- provide option to build an initramfs out of the current rootfs. Closes #881

target/Config.in

@@ -10,6 +10,7 @@ source "target/squashfs/Config.in"
 source "target/tar/Config.in"
 source "target/cpio/Config.in"
 source "target/iso9660/Config.in"
+source "target/initramfs/Config.in"
 
 comment "bootloader for target device"
 

target/initramfs/Config.in

@@ -0,0 +1,16 @@
+config BR2_TARGET_ROOTFS_INITRAMFS
+	bool "initramfs for initial ramdisk of linux kernel"
+	default n
+	help
+	  Build a file which is usable for the gen_init_cpio tool
+	  at linux kernel build. 
+	  This file is normally called initramfs_list and can be
+	  generated with gen_initramfs_list.sh script from the root
+	  directory structure. 
+	  The file is then used in the kernel build process to generate
+	  the cpio filesystem for the initial ramdisk. Make sure that
+	  you configure this file in kernel build configuration.
+	  The location in the kernel build configuration menu is
+	  Device Drivers -> Block devices -> Initramfs source file(s).
+	  The configuration variable is CONFIG_INITRAMFS_SOURCE
+

target/initramfs/gen_initramfs_list.sh

@@ -0,0 +1,203 @@
+#!/bin/sh
+# Copyright (C) Martin Schlemmer <azarah@nosferatu.za.org>
+# Released under the terms of the GNU GPL
+#
+# Generate a newline separated list of entries from the file/directory
+# supplied as an argument.
+#
+# If a file/directory is not supplied then generate a small dummy file.
+#
+# The output is suitable for gen_init_cpio built from usr/gen_init_cpio.c.
+#
+
+default_initramfs() {
+	cat <<-EOF
+		# This is a very simple, default initramfs
+
+		dir /dev 0755 0 0
+		nod /dev/console 0600 0 0 c 5 1
+		dir /root 0700 0 0
+	EOF
+}
+
+filetype() {
+	local argv1="$1"
+
+	# symlink test must come before file test
+	if [ -L "$argv1" ]; then
+		echo "slink"
+	elif [ -f "$argv1" ]; then
+		echo "file"
+	elif [ -d "$argv1" ]; then
+		echo "dir"
+	elif [ -b "$argv1" -o -c "$argv1" ]; then
+		echo "nod"
+	elif [ -p "$argv1" ]; then
+		echo "pipe"
+	elif [ -S "$argv1" ]; then
+		echo "sock"
+	else
+		echo "invalid"
+	fi
+	return 0
+}
+
+print_mtime() {
+	local argv1="$1"
+	local mymtime="0"
+
+	if [ -e "$argv1" ]; then
+		mymtime=$(find "$argv1" -printf "%T@\n" | sort -r | head -n 1)
+	fi
+	
+	echo "# Last modified: $mymtime"
+	echo
+}
+
+parse() {
+	local location="$1"
+	local name=$(echo "$location" | sed -e "s,$srcdir,,")
+	# change '//' into '/'
+	name=$(echo $name | sed -e 's,/[/]*,/,g')
+	local mode="$2"
+	local uid="$3"
+	local gid="$4"
+	local ftype=$(filetype "$location")
+	# remap uid/gid to 0 if necessary
+	[ "x$uid" != "x" ] && [ $uid -eq $root_uid ] && uid=0
+	[ "x$gid" != "x" ] && [ $gid -eq $root_gid ] && gid=0
+	local str="$mode $uid $gid"
+
+	[ "$ftype" = "invalid" ] && return 0
+	[ "$location" = "$srcdir" ] && return 0
+
+	case "$ftype" in
+		"file")
+			str="$ftype $name $location $str"
+			;;
+		"nod")
+			local devtype=
+			local maj=$(LC_ALL=C ls -l "$location" | \
+					awk '{sub(/,/, "", $5); print $5}')
+			local min=$(LC_ALL=C ls -l "$location" | \
+					awk '{print $6}')
+
+			if [ -b "$location" ]; then
+				devtype="b"
+			else
+				devtype="c"
+			fi
+			str="$ftype $name $str $devtype $maj $min"
+			;;
+		"slink")
+			local target=$(LC_ALL=C ls -l "$location" | \
+					awk '{print $11}')
+			str="$ftype $name $target $str"
+			;;
+		*)
+			str="$ftype $name $str"
+			;;
+	esac
+
+	echo "$str"
+
+	return 0
+}
+
+usage() {
+	printf    "Usage:\n"
+	printf    "$0 [ [-u <root_uid>] [-g <root_gid>] [-d | <cpio_source>] ] . . .\n"
+	printf    "\n"
+	printf -- "-u <root_uid>  User ID to map to user ID 0 (root).\n"
+	printf    "               <root_uid> is only meaningful if <cpio_source>\n"
+	printf    "               is a directory.\n"
+	printf -- "-g <root_gid>  Group ID to map to group ID 0 (root).\n"
+	printf    "               <root_gid> is only meaningful if <cpio_source>\n"
+	printf    "               is a directory.\n"
+	printf    "<cpio_source>  File list or directory for cpio archive.\n"
+	printf    "               If <cpio_source> is not provided then a\n"
+	printf    "               a default list will be output.\n"
+	printf -- "-d             Output the default cpio list.  If no <cpio_source>\n"
+	printf    "               is given then the default cpio list will be output.\n"
+	printf    "\n"
+	printf    "All options may be repeated and are interpreted sequentially\n"
+	printf    "and immediately.  -u and -g states are preserved across\n"
+	printf    "<cpio_source> options so an explicit \"-u 0 -g 0\" is required\n"
+	printf    "to reset the root/group mapping.\n"
+}
+
+build_list() {
+	printf "\n#####################\n# $cpio_source\n"
+
+	if [ -f "$cpio_source" ]; then
+		print_mtime "$cpio_source"
+		cat "$cpio_source"
+	elif [ -d "$cpio_source" ]; then
+		srcdir=$(echo "$cpio_source" | sed -e 's://*:/:g;s:/$::')
+		dirlist=$(find "$srcdir" -printf "%p %m %U %G\n" 2>/dev/null)
+
+		# If $dirlist is only one line, then the directory is empty
+		if [  "$(echo "$dirlist" | wc -l)" -gt 1 ]; then
+			print_mtime "$cpio_source"
+		
+			echo "$dirlist" | \
+			while read x; do
+				parse $x
+			done
+		else
+			# Failsafe in case directory is empty
+			default_initramfs
+		fi
+	else
+		echo "  $0: Cannot open '$cpio_source'" >&2
+		exit 1
+	fi
+}
+
+
+root_uid=0
+root_gid=0
+
+while [ $# -gt 0 ]; do
+	arg="$1"
+	shift
+	case "$arg" in
+		"-u")
+			root_uid="$1"
+			shift
+			;;
+		"-g")
+			root_gid="$1"
+			shift
+			;;
+		"-d")
+			default_list="$arg"
+			default_initramfs
+			;;
+		"-h")
+			usage
+			exit 0
+			;;
+		*)
+			case "$arg" in
+				"-"*)
+					printf "ERROR: unknown option \"$arg\"\n" >&2
+					printf "If the filename validly begins with '-', then it must be prefixed\n" >&2
+					printf "by './' so that it won't be interpreted as an option." >&2
+					printf "\n" >&2
+					usage >&2
+					exit 1
+					;;
+				*)
+					cpio_source="$arg"
+					build_list
+					;;
+			esac
+			;;
+	esac
+done
+
+# spit out the default cpio list if a source hasn't been specified
+[ -z "$cpio_source" -a -z "$default_list" ] && default_initramfs
+
+exit 0

target/initramfs/initramfs.mk

@@ -0,0 +1,43 @@
+#############################################################
+#
+# Make a initramfs_list file to be used by gen_init_cpio
+# gen_init_cpio is part of the 2.6 linux kernels to build an 
+# initial ramdisk filesystem based on cpio
+#
+#############################################################
+
+ifeq ($(strip $(BR2_TARGET_ROOTFS_INITRAMFS)),y)
+INITRAMFS_TARGET:=$(IMAGE).initramfs_list
+else
+INITRAMFS_TARGET:= #nothing
+endif
+
+$(INITRAMFS_TARGET) initramfs: host-fakeroot makedevs
+	-find $(TARGET_DIR) -type f -perm +111 | xargs $(STRIP) 2>/dev/null || true;
+	rm -rf $(TARGET_DIR)/usr/man
+	rm -rf $(TARGET_DIR)/usr/info
+	-/sbin/ldconfig -r $(TARGET_DIR) 2>/dev/null
+	# Use fakeroot to pretend all target binaries are owned by root
+	rm -f $(STAGING_DIR)/_fakeroot.$(notdir $(TAR_TARGET))
+	touch $(STAGING_DIR)/.fakeroot.00000
+	cat $(STAGING_DIR)/.fakeroot* > $(STAGING_DIR)/_fakeroot.$(notdir $(TAR_TARGET))
+	echo "chown -R 0:0 $(TARGET_DIR)" >> $(STAGING_DIR)/_fakeroot.$(notdir $(TAR_TARGET))
+	# Use fakeroot to pretend to create all needed device nodes
+	echo "$(STAGING_DIR)/bin/makedevs -d $(TARGET_DEVICE_TABLE) $(TARGET_DIR)" \
+		>> $(STAGING_DIR)/_fakeroot.$(notdir $(TAR_TARGET))
+	# Use fakeroot so gen_initramfs_list.sh  believes the previous fakery
+	echo "$(CONFIG_SHELL) target/initramfs/gen_initramfs_list.sh -u 0 -g 0 $(TARGET_DIR) > $(INITRAMFS_TARGET)" \
+		>> $(STAGING_DIR)/_fakeroot.$(notdir $(TAR_TARGET))
+	chmod a+x $(STAGING_DIR)/_fakeroot.$(notdir $(TAR_TARGET))
+	$(STAGING_DIR)/usr/bin/fakeroot -- $(STAGING_DIR)/_fakeroot.$(notdir $(TAR_TARGET))
+	-rm -f $(STAGING_DIR)/_fakeroot.$(notdir $(TAR_TARGET))
+
+initramfs-source:
+
+initramfs-clean:
+ifeq ($(strip $(BR2_TARGET_ROOTFS_INITRAMFS)),y)
+	-rm -f $(INITRAMFS_TARGET)
+endif
+initramfs-dirclean:
+
+