Modified update-extlinux script to update syslinux configuration

update-syslinux

#!/bin/sh
# Taken from https://git.adelielinux.org/adelie/packages/-/blob/abefa433c8e2199520e5a763e415e7ed4d60f551/legacy/syslinux/update-extlinux
# Modified for Legacy & UEFI Syslinux

version=
default=0
timeout=5
verbose=0

conf=/boot/syslinux/syslinux.cfg
myconf=/etc/update-syslinux.conf

# read in syslinux settings
if [ -f "$myconf" ]; then
	. $myconf
fi

everbose() {
	if [ "$verbose" = "0" ]; then
		return
	fi

	echo $*
}

ewarn() {
	echo "WARNING:" $@ >&2
}

eerror() {
	echo "ERROR:" $@ >&2
	return 1
}

usage() {
	echo "usage: $0 [-v|--verbose] [--warn-only]"
}

while [ $# -gt 0 ]; do
	opt="$1"
	shift
	case "$opt" in
	-v|--verbose)
		verbose=1
		;;
	--warn-only)
		warn_only=1
		;;
	--)
		break
		;;
	-*)
		usage
		exit 1
		;;
	esac
done

everbose "Updating syslinux configuration."

if [ "x$root" = "x" ]; then
	ewarn "Root device is not specified in $myconf."
	blkid_export=$(findmnt -n -o SOURCE /)
	if [ -n "$blkid_export" ]; then
		export $blkid_export
	fi
	if [ -z "$UUID" ]; then
		# try parse /proc/mount for mounted /
		dev=$(awk '$2 == "/" {dev=$1} END {print dev}' /proc/mounts)
		if [ -n "$dev" ]; then
			blkid_export=$(blkid -o export $dev)
			if [ -n "$blkid_export" ]; then
				export "$blkid_export"
			fi
		fi
	fi
	if [ -z "$UUID" ]; then
		if [ -z "$dev" ]; then
			if [ -n "$warn_only" ]; then
				ewarn "Failed to detect root device. syslinux.conf is not updated"
				exit 0
			else
				eerror "Failed to detect root device"
				exit 1
			fi
		else
			root=$dev
		fi
	else
		root=UUID=$UUID
	fi
	everbose "Root device is: $root"
fi

rtimeout=$(( ${timeout} * 10 ))
syslinux_menu=menu.c32
menu_hidden=

# vesa menu has been requested?
if [ "$vesa_menu" = "1" ]; then
	syslinux_menu=vesamenu.c32
fi

umask 0022
rm -f $conf.new
echo "# Generated by update-syslinux $version" > $conf.new
if [ -n "$serial_port" ]; then
	echo "SERIAL $serial_port ${serial_baud:-115200}" >> $conf.new
fi
echo "DEFAULT $syslinux_menu" >> $conf.new
echo "PROMPT 0" >> $conf.new
echo "MENU TITLE Adelie $(uname -s) Boot Menu" >> $conf.new
if [ "$hidden" = "1" ]; then
	echo "MENU HIDDEN" >> $conf.new
fi
echo "MENU AUTOBOOT Adelie will be booted automatically in # seconds." >> $conf.new
echo "TIMEOUT $rtimeout" >> $conf.new

lst=0
if [ -f "/boot/xen.gz" ]; then
	for kernel in $(find /boot -name "vmlinuz-*" -type f); do
		tag=$(basename $kernel | cut -b9-)
		everbose "Found Xen hypervisor: /boot/xen.gz, kernel: $kernel"

		if [ -f "/boot/initramfs-$tag" ]; then
			everbose "Found initramfs: /boot/initramfs-$tag"
			initramfs="initramfs-$tag"
		else
			initramfs=
		fi
		label=xen-$(grep -w -l $tag /usr/share/kernel/*/kernel.release \
				| cut -d/ -f5)
		if [ "$label" = "xen-" ]; then
			label=xen-$lst
		fi

		echo "LABEL $label" >> $conf.new
		if [ "$label" = "$default" ]; then
			echo "  MENU DEFAULT" >> $conf.new
		fi
		echo "  MENU LABEL Xen + Linux $tag" >> $conf.new
		echo "  COM32 mboot.c32" >> $conf.new
		echo "  APPEND xen.gz $xen_opts --- $(basename $kernel) root=$root modules=${modules}${TYPE:+,$TYPE} $default_kernel_opts --- $initramfs" >> $conf.new
		echo "" >> $conf.new
		lst=$(($lst + 1))
	done
fi

for kernel in $(find /boot -name "vmlinuz*" -type f); do
	case $kernel in
	*vmlinuz) tag=vanilla;;
	*vmlinuz-*)  tag=$(basename $kernel | cut -b9-);;
	*) continue;;
	esac
	everbose "Found kernel: $kernel"
	label=$(grep -w -l $tag /usr/share/kernel/*/kernel.release | cut -d/ -f5)
	if [ -z "$label" ]; then
		if [ "$tag" = vanilla ]; then
			label="vanilla"
		else
			label=$lst
		fi
	fi
	echo "LABEL $label" >> $conf.new
	if [ "$label" = "$default" ]; then
		echo "  MENU DEFAULT" >> $conf.new
	fi
	echo "  MENU LABEL Linux $tag" >> $conf.new
	echo "  LINUX $(basename $kernel)" >> $conf.new
	if [ -f "/boot/initramfs-$tag" ]; then
		everbose "Found initramfs: /boot/initramfs-$tag"
		echo "  INITRD initramfs-$tag" >> $conf.new
	fi
	echo "  APPEND root=$root modules=${modules}${TYPE:+,$TYPE} $default_kernel_opts" >> $conf.new
	echo "" >> $conf.new
	lst=$(($lst + 1))
done

if [ -n "$password" ]; then
	echo "NOESCAPE 1" >> $conf.new
	echo "MENU MASTER PASSWD $password" >> $conf.new
	echo "" >> $conf.new
	chmod o-r $conf.new
fi

everbose "$lst entries found."

for entry in /etc/update-syslinux.d/*; do
	[ -f "$entry" ] && { cat $entry; echo ""; } >> $conf.new
done

echo "MENU SEPARATOR" >> $conf.new
echo "" >> $conf.new

if [ -f "/boot/hdt.c32" ]; then
	everbose "Found Hardware Detection Tool: /boot/hdt.c32"
	echo "LABEL hdt" >> $conf.new
	echo "  MENU LABEL Hardware info" >> $conf.new
	if [ -n "$password" ]; then
		echo "  MENU PASSWD" >> $conf.new
	fi
	echo "  COM32 hdt.c32" >> $conf.new
	if [ -f "/boot/memtest" ]; then
		everbose "Found memtest86+: /boot/memtest"
		echo "  APPEND memtest=memtest" >> $conf.new
	fi
	echo "" >> $conf.new
elif [ -f "/boot/memtest" ]; then
	everbose "Found memtest86+: /boot/memtest"
	echo "LABEL memtest" >> $conf.new
	echo "  MENU LABEL Memtest86+" >> $conf.new
        echo "  KERNEL memtest" >> $conf.new
	echo "" >> $conf.new
fi

for i in reboot poweroff; do
	[ -f "/boot/$i.c32" ] || continue
	everbose "Found $i"
	# make first char capital
	cap=$( echo $i | awk '{sub(".", substr(toupper($0),1,1), $0); print}' )
	echo "LABEL $i" >> $conf.new
	echo "  MENU LABEL $cap" >> $conf.new
        echo "  COM32 $i.c32" >> $conf.new
	echo "" >> $conf.new
done

if cmp -s $conf.new $conf; then
	everbose "Configuration unchanged."
	rm $conf.new
fi

if [ "$overwrite" != "1" ]; then
	exit 0
elif [ -f "$conf.new" ]; then
	# keep a backup just in case
	if [ -f "$conf" ]; then
		mv $conf $conf.old
	fi

	mv $conf.new $conf
fi

update-syslinux.conf

# configuration for extlinux config builder

# overwrite
# Overwrite current /boot/extlinux.conf. If this is not '1' we will only
# write to /boot/extlinux.conf.new
overwrite=1

# vesa_menu
# use fancy vesa menu (vesamenu.c32) menus, won't work with serial
# vesa_menu=1

# default_kernel_opts
# default kernel options
default_kernel_opts=rw

# modules
# modules which should be loaded before pivot_root
modules=
#sd-mod,usb-storage,ext4

# root
# root device - if not specified, will be guessed using
# findmnt -n -o SOURCE /
root=

# verbose
# if set to non-zero, update-extlinux will be a lot more verbose.
verbose=0

# hidden
# if set to non-zero, the boot menu will be hidden by default.
hidden=1

# timeout
# number of seconds to wait before booting default
timeout=5

# default
# default kernel to boot
default=6.1.0-12-amd64

# serial_port
# serial port number - if not specified, serial console will be disabled
serial_port=

# serial_baud
# the baudrate for the serial port. Will use 115200 if unset
serial_baud=115200

# xen_opts
# options to hand to xen hypervisor, useful ones are:
#    dom0_mem=256M (give domain-0 environment 256M ram)
xen_opts=dom0_mem=256M

# if you copy /usr/share/syslinux/reboot.c32 to /boot/, a menu entry
# will be auto-generated for it

# if you copy hdt.c32, libgpl.c32, and libmenu.c32 from /usr/share/syslinux/
# to /boot/, a menu entry will be auto-generated for HDT

# if you download and install /boot/memtest, then if HDT is present it
# will use it, else a separate menu entry will be auto-generated for
# memtest

# optional password
# you can generate a SHA512 password using: mkpasswd
#
# if you assign a password, you should make this file world-unreadable
#
# if a password is assigned, the menu entries can't be edited at boot
# time, and HDT if present is password-protected
#
# you can also include "MENU PASSWD" in any custom entries you have in
# /etc/update-extlinux.d/
password=''