~ubuntu-virt/ubuntu/maverick/eucalyptus/2.0

Description: add support for booting a multiboot image from a floppy

 This adds a tool 'mk-mb-loader' which takes a multiboot compliant image

 and puts it onto a floppy disk image and loads it.

 .

 It also contains modifications to gen_kvm_libvirt_xml that

 a.) make mk-mb-loader run 

 b.) modify libvirt xml output to add a floppy disk and boot

     off it rather than booting via '<kernel>'

 .

 The hack to boot off of a floppy is required because when a multiboot

 image is loaded by 'kvm -kernel "mb.img"', it will not have access to

 scsi disks.  That means that if a scsi disk is the root block device

 that the multiboot image will not see any disks.  

 .

 The solution is to boot via floppy instead.  The mk-mb-image creates

 a floppy disk that loads the user provided multiboot image.

 .

 In the future, this patch can be dropped if either of the following occur:

 a.) scsi root disk support is abandoned

 b.) seabios gains native support for scsi disks, such that 

     'kvm -kernel <mb.img' has access to scsi disks as it has access to

     ide or virtio disks in seabios 0.6.0-0ubuntu1.

 .

 That would provide a much more clean solution of simply booting with 

 '-kernel' whatever the user provided.

Author: Scott Moser <scott.moser@canonical.com>

Last-Update: 2010-07-28

Bug: https://bugs.launchpad.net/eucalyptus/+bug/611144

--- a/node/handlers.c

+++ b/node/handlers.c

@@ -380,6 +380,7 @@

 			char **xml)

 {

     char buf [MAX_PATH];

+    char patharg [MAX_PATH];

     snprintf(buf, MAX_PATH, "%s", gen_libvirt_cmd_path);

     if (strnlen(ramdiskId, CHAR_BUFFER_SIZE)) {

@@ -395,6 +396,9 @@

     if (params->disk > 0) { /* TODO: get this info from scMakeImage */

         strncat (buf, " --ephemeral", MAX_PATH);

     }

+    snprintf(buf+strnlen(buf,MAX_PATH), MAX_PATH-strnlen(buf,MAX_PATH),

+             " --basepath='%s'", disk_path);

+

     * xml = system_output (buf);

     if ( ( * xml ) == NULL ) {

         logprintfl (EUCAFATAL, "%s: %s\n", gen_libvirt_cmd_path, strerror (errno));

--- a/tools/gen_kvm_libvirt_xml

+++ b/tools/gen_kvm_libvirt_xml

@@ -76,6 +76,8 @@

 our $local_kvm="";

 our $use_virtio_net = 0;

 our $use_virtio_root = 0;

+our $base_path = "";

+our $multi_boot_floppy = 0;

 if ( -x "/usr/bin/kvm" ) {

     $local_kvm="/usr/bin/kvm";

@@ -90,24 +92,38 @@

            'ephemeral'      => sub { }, # option ignored 

            'virtionet'      => sub { $use_virtio_net = 1; },

            'virtioroot'      => sub { $use_virtio_root = 1; },

+           'basepath=s'      => \$base_path,

 		   ) or exit (1);

+if ($base_path && &is_multiboot_img($base_path . "/kernel")) {

+   $multi_boot_floppy = 1;

+}

+

 print <<EOF;

 <domain type='kvm'>

     <name>NAME</name>

     <os>

     <type>hvm</type>

-        <kernel>BASEPATH/kernel</kernel>

 EOF

-if ( $use_ramdisk ) {

-    print "        <initrd>BASEPATH/ramdisk</initrd>\n";

-}

-

-if ( $use_virtio_root ) {

-    print "        <cmdline>root=/dev/vda1 console=ttyS0</cmdline>\n"

+if ( $multi_boot_floppy ) {

+    my $mb_load_cmd = "/usr/share/eucalyptus/mk-mb-loader " .

+        "'" . $base_path . "/kernel' '" .  $base_path .  "/loader' 2>&1";

+    my $mb_out = `$mb_load_cmd`;

+    if ( $? != 0 ) { print("failed to make loader\n${mb_out}\n"); exit(1); }

+    print "        <boot dev='fd'/>\n";

+    print "        <boot dev='hd'/>\n";

 } else {

-    print "        <cmdline>root=/dev/sda1 console=ttyS0</cmdline>\n"

+    print "        <kernel>BASEPATH/kernel</kernel>\n";

+    if ( $use_ramdisk ) {

+        print "        <initrd>BASEPATH/ramdisk</initrd>\n";

+    }

+

+    if ( $use_virtio_root ) {

+        print "        <cmdline>root=/dev/vda1 console=ttyS0</cmdline>\n"

+    } else {

+        print "        <cmdline>root=/dev/sda1 console=ttyS0</cmdline>\n"

+    }

 }

 print <<EOF;

@@ -121,6 +137,15 @@

         <emulator>$local_kvm</emulator>

 EOF

+if ( $multi_boot_floppy ) {

+   print <<EOF

+        <disk type='file' device='floppy'>

+            <source file='BASEPATH/loader'/>

+            <target dev='fda' bus='fdc'/>

+        </disk>

+EOF

+}

+

 if ( $use_virtio_root ) {

     print <<EOF;

         <disk type='file' device='disk'>

@@ -163,3 +188,42 @@

     </devices>

 </domain>

 EOF

+

+# This checks if a binary looks like a multiboot image

+# The check is similar to grub 0.97's mbchk and to kvm's multiboot

+# check in hw/multiboot.c:load_multiboot

+sub is_multiboot_img

+{

+    my $kpath=$_[0];

+    my $buf;

+    my $found = 0;

+    my $header_magic = 0x1BADB002;

+    my $header_size = 32;     # there are 8 uint32 values

+    my $search_bytes = 8192;  # copied from kvm and grub's mbchk

+    my $magic = 0;

+    my $flags = 0;

+    my $checksum = 0;

+    my $count = 0;

+

+    if (! (-s $kpath)) { return(0); }

+    open INF, $kpath or return(0);

+    binmode INF;

+    if (!($count = read (INF, $buf, $search_bytes))) {

+        close INF;

+        return(0);

+    }

+    close INF;

+    for(my $i=0;$i < ($count - $header_size);$i=$i+4) {

+        if (unpack("V",substr($buf,$i,4)) == $header_magic ) {

+            $found=$i; last;

+        }

+    }

+

+    if ($found == 0) { return(0); }

+    ($magic,$flags,$checksum) = unpack("VVV",substr($buf,$found,4*3));

+    # magic + flags + checksum == (uint32) 0 == 2**32

+    if(($magic+$flags+$checksum) % 2**32 == 0 ) {

+        return(1);

+    }

+    return(0);

+}

--- a/tools/Makefile

+++ b/tools/Makefile

@@ -47,6 +47,7 @@

 	@$(INSTALL) -m 755 connect_iscsitarget.pl $(DESTDIR)$(datarootdir)/eucalyptus

 	@$(INSTALL) -m 755 disconnect_iscsitarget.pl $(DESTDIR)$(datarootdir)/eucalyptus

 	@$(INSTALL) -m 755 get_iscsitarget.pl $(DESTDIR)$(datarootdir)/eucalyptus

+	@$(INSTALL) -m 755 mk-mb-loader $(DESTDIR)$(datarootdir)/eucalyptus

 uninstall: 

 	@$(RM) -f $(DESTDIR)$(etcdir)/init.d/eucalyptus-cloud

@@ -68,4 +69,5 @@

 	@$(RM) -f $(DESTDIR)$(sbindir)/euca_conf

 	@$(RM) -f $(DESTDIR)/etc/bash_completion.d/euca_conf

 	@$(RM) -f $(DESTDIR)$(sbindir)/euca_sync_key

+	@$(RM) -f $(DESTDIR)$(datarootdir)/eucalyptus/mk-mb-loader

--- /dev/null

+++ b/tools/mk-mb-loader

@@ -0,0 +1,113 @@

+#!/bin/sh

+# vi: ts=4 noexpandtab

+#

+#    Copyright (C) 2010 Canonical Ltd.

+#

+#    Authors: Scott Moser <smoser@canonical.com>

+#

+#    This program is free software: you can redistribute it and/or modify

+#    it under the terms of the GNU General Public License as published by

+#    the Free Software Foundation, version 3 of the License.

+#

+#    This program is distributed in the hope that it will be useful,

+#    but WITHOUT ANY WARRANTY; without even the implied warranty of

+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+#    GNU General Public License for more details.

+#

+#    You should have received a copy of the GNU General Public License

+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

+

+TEMP_D=""

+

+error() { echo "$@" 1>&2; }

+fail() { [ $# -eq 0 ] || error "$@"; exit 1; }

+Usage() {

+	cat <<EOF

+Usage: ${0##*/} loader.img output.img

+   Create a multiboot floppy image that will multiboot 'loader.img'

+   where loader.img is a multiboot complient loader

+

+   The output.img file can then be booted with

+      kvm -fda output.img -boot a -drive ...

+   and will load 'loader.img'

+EOF

+}

+bad_Usage() { Usage 1>&2; fail "$@"; }

+cleanup() {

+	[ -z "${TEMP_D}" -o ! -d "${TEMP_D}" ] || rm -Rf "${TEMP_D}"

+}

+

+getsize() {

+	local f="$1" size=""

+	size=$(ls -l "${f}" 2>/dev/null | awk '{print $5}') &&

+		[ -n "${size}" ] && _RET=${size} && return 0

+}

+checksize() {

+	getsize "$1" || return 1

+	[ "${_RET}" "$2" "$3" ]

+}

+

+mk_grub_rescue() {

+	local input=${1} output=${2}

+	local bdir="${TEMP_D}/bdir"

+	local err="${TEMP_D}/err"

+	local modules="configfile"

+	local modules=""

+	mkdir "${bdir}" &&

+		mkdir -p "${bdir}/boot/grub" &&

+		cp "${input}" "${bdir}/boot/grub/loader.img" &&

+		cat > "${bdir}/boot/grub/grub.cfg" <<EOF

+multiboot /boot/grub/loader.img

+boot

+EOF

+		[ $? -eq 0 ] || return

+		grub-mkrescue --output="${output}" \

+			${modules:+"--modules=${modules}"} "${bdir}" > "${err}" 2>&1 ||

+			{ cat "${err}" 1>&2; return 1; }

+}

+

+short_opts="h"

+long_opts="help"

+getopt_out=$(getopt --name "${0##*/}" \

+	--options "${short_opts}" --long "${long_opts}" -- "$@") &&

+	eval set -- "${getopt_out}" ||

+	bad_Usage

+

+mode="grub-rescue-floppy"

+while [ $# -ne 0 ]; do

+	cur=${1}; next=${2};

+	case "$cur" in

+		-h|--help) Usage; exit 0;;

+		--) shift; break;;

+	esac

+	shift;

+done

+

+[ $# -eq 2 ] || bad_Usage "must multiboot loader input and output file"

+

+TEMP_D=$(mktemp -d "${TMPDIR:-/tmp}/.${0##*/}.XXXXXX") ||

+	fail "failed to make tempd"

+trap cleanup EXIT

+

+loader=${1}

+output=${2}

+

+case "${mode}" in

+	grub-rescue-floppy)

+		mk_grub_rescue "${loader}" "${output}" ||

+			fail "failed to make rescue floppy"

+		checksize "${output}" -lt $((2880*1024)) ||

+			fail "output of mk_rescue was to large for floppy"

+		size=${_RET}

+		truncate --size 2880K "${output}" ||

+			fail "failed to pad ${output} to 2880K"

+		echo "created ${mode} loader in ${output} (payload $size)"

+		;;

+	grub-rescue-cdrom)

+		mk_grub_rescue "${loader}" "${output}" ||

+			fail "failed to make rescue cdrom"

+		echo "created ${mode} loader in ${output}"

+		;;

+esac

+

+[ $? -eq 0 ] || fail "failed to create loader"