Use syslinux as legacy BIOS bootloader

- Install syslinux by default, fallback to GRUB
- Generate syslinux.cfg

4 files changed, 112 insertions, 21 deletions

diff --git a/buildlive b/buildlive
index aeec242..3de3b03 100755
--- a/buildlive
+++ b/buildlive
@@ -107,6 +107,8 @@ fi
 if [[ "$DOWNLOAD_ONLY" == 0 ]]; then
 	UUID="$(findmnt -o UUID --raw --noheadings $ROOTPATH \
 		|| fatalerror "UUID of $ROOTPATH not found, not a mountpoint?")"
+	BOOTPART="$(findmnt -o SOURCE --raw --noheadings $BOOTPATH \
+		|| fatalerror "$BOOTPATH seems not a mountpoint!")"
 	# liveusb kernel and data should be placed on one disk
 	# so get DEVNAME by the mountpoint of ROOTPATH is ok
 	DEVNAME="/dev/$(getdiskbypart "/dev/disk/by-uuid/$UUID")"
@@ -114,7 +116,8 @@ if [[ "$DOWNLOAD_ONLY" == 0 ]]; then
 	KERNELDIR="$BOOTPATH/liveusb-kernel"
 	DATADIR="$ROOTPATH/liveusb-data"
 	GRUBCFG="$BOOTPATH/grub/grub.cfg"
-	install -d "$BOOTPATH/grub"
+	SYSLINUXCFG="$BOOTPATH/syslinux/syslinux.cfg"
+	install -d "$BOOTPATH/grub" "$BOOTPATH/syslinux"
 	install -d "$KERNELDIR" "$DATADIR"
 	msg "Files will be copy to $ROOTPATH"
 fi
@@ -145,23 +148,8 @@ if [[ "$DOWNLOAD_ONLY" == 1 ]]; then
 	exit 0
 fi
 
-echo '# The live USB grub.cfg file' > "$GRUBCFG"
-
-if [ -z "$TXTMODE" ]; then
-	cat >> "$GRUBCFG" << 'EOF'
-if [ ${grub_platform} == efi ]; then
-	insmod all_video
-	insmod font
-	if loadfont /grub/fonts/unicode.pf2; then
-		insmod gfxterm
-		set gfxmode=auto
-		set gfxpayload=keep
-		terminal_output gfxterm
-	fi
-fi
-
-EOF
-fi
+grubcfg_header > "$GRUBCFG"
+syslinux_header > "$SYSLINUXCFG"
 
 for i in `seq 1 ${#DISTROLIST[@]}`
 do
@@ -174,14 +162,18 @@ do
 		install_live
 	fi
 	gen_grubcfg "$DISTRO" >> "$GRUBCFG"
+	gen_syslinux "$DISTRO" >> "$SYSLINUXCFG"
 done
 
 if [ "$GRUBCFG_ONLY" == 1 ]; then
-	msg 'Only generate grub.cfg, will not install GRUB.'
+	msg 'Only generate grub.cfg and syslinux.cfg, will not install bootloader.'
 elif [ "$INSTALL_GRUB" == 1 ]; then
-	read -p 'Answer Y to install GRUB.[Y/n] '
+	read -p 'Answer Y to install bootloader.[Y/n] '
 	if [[ "$REPLY" =~ ^[Yy]|^$ ]]; then
-		as-root grub-install --force --boot-directory="$BOOTPATH" --target=i386-pc "$DEVNAME"
+		if ! as-root ./install_syslinux "$DEVNAME" "$BOOTPART" "$BOOTPATH"; then
+			msg 'Failed to install syslinux, try to install GRUB as legacy BIOS bootloader.'
+			as-root grub-install --force --boot-directory="$BOOTPATH" --target=i386-pc "$DEVNAME"
+		fi
 		as-root grub-install --boot-directory="$BOOTPATH" --efi-directory="$BOOTPATH" --bootloader-id=grub --target=x86_64-efi --removable --no-nvram "$DEVNAME"
 	fi
 fi
diff --git a/functions.sh b/functions.sh
index c077231..00e0e0c 100644
--- a/functions.sh
+++ b/functions.sh
@@ -59,6 +59,19 @@ gen_grubcfg() {
 	fi
 }
 
+gen_syslinux() {
+	local entry allentries count name
+	allentries=("distro/$1/entry"*)
+	name=$(echo $1|sed 's/\//_/g')
+	count=0
+	for entry in "${allentries[@]}"
+	do
+		UUID="$UUID" ISOFILE="$ISOFILE" LABEL="$name$count" \
+			./mksyslinux.sh "$entry"
+		count=$(($count+1))
+	done
+}
+
 download_iso() {
 	mkdir -p "$ISOPATH"
 	for url in ${mirrorlist[@]}
@@ -119,3 +132,41 @@ as-root() {
 		su -c "$*"
 	fi
 }
+
+syslinux_header() {
+	cat << EOF
+UI menu.c32
+
+MENU TITLE Live USB
+MENU COLOR border       30;44   #40ffffff #a0000000 std
+MENU COLOR title        1;36;44 #9033ccff #a0000000 std
+MENU COLOR sel          7;37;40 #e0ffffff #20ffffff all
+MENU COLOR unsel        37;44   #50ffffff #a0000000 std
+MENU COLOR help         37;40   #c0ffffff #a0000000 std
+MENU COLOR timeout_msg  37;40   #80ffffff #00000000 std
+MENU COLOR timeout      1;37;40 #c0ffffff #00000000 std
+MENU COLOR msg07        37;40   #90ffffff #a0000000 std
+MENU COLOR tabmsg       31;40   #30ffffff #00000000 std
+
+EOF
+}
+
+grubcfg_header() {
+	echo '# The live USB grub.cfg file'
+
+	if [ -z "$TXTMODE" ]; then
+		cat  << 'EOF'
+if [ ${grub_platform} == efi ]; then
+	insmod all_video
+	insmod font
+	if loadfont /grub/fonts/unicode.pf2; then
+		insmod gfxterm
+		set gfxmode=auto
+		set gfxpayload=keep
+		terminal_output gfxterm
+	fi
+fi
+
+EOF
+	fi
+}
diff --git a/install_syslinux b/install_syslinux
new file mode 100755
index 0000000..d4fdbf9
--- /dev/null
+++ b/install_syslinux
@@ -0,0 +1,17 @@
+#!/bin/bash
+# Copyright (C)  2018 Iru Cai <mytbk920423@gmail.com>
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Example: ./install_syslinux /dev/sdb /dev/sdb1 /media/boot
+set -e
+
+SYSLINUX_BIOS=/usr/lib/syslinux/bios
+DEVNAME="$1"
+BOOTPART="$2"
+BOOTPATH="$3"
+
+test -d "$SYSLINUX_BIOS"
+syslinux -i "$BOOTPART"
+dd bs=440 count=1 conv=notrunc if="$SYSLINUX_BIOS/mbr.bin" of="$DEVNAME"
+install -d "$BOOTPATH/syslinux"
+cp "$SYSLINUX_BIOS"/*.c32 "$BOOTPATH/syslinux"
diff --git a/mksyslinux.sh b/mksyslinux.sh
new file mode 100755
index 0000000..f433fe8
--- /dev/null
+++ b/mksyslinux.sh
@@ -0,0 +1,31 @@
+# Copyright (C)  2018 Iru Cai <mytbk920423@gmail.com>
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# generate syslinux menuentry
+# usage: UUID="$UUID" ISOFILE="$ISOFILE" LABEL="$LABEL" \
+#          ./mkgrubcfg.sh <entryfile>
+#
+# variables in entryfile:
+# - UUID: the UUID of the partition
+# - ISOFILE: the file name of iso (needed to pass to the entry file)
+# - LABEL: syslinux label
+#
+# parameters in entry file:
+# - TITLE: GRUB menu entry title
+# - KERNEL: path to kernel image
+# - INITRD: path to initramfs/initrd image
+# - OPTION: kernel command line
+# - X64: y/n, indicates whether it's 64-bit
+
+source "$1"
+_INITRD=$(echo ${INITRD[*]}|sed 's/ /,/g')
+
+cat << EOF
+LABEL $LABEL
+MENU LABEL $TITLE
+LINUX $KERNEL
+INITRD $_INITRD
+APPEND $OPTION
+EOF
+
+echo