This file is indexed.

/lib/live/boot/0030-verify-checksums is in open-infrastructure-system-boot 20161101-lts2-1.

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The actual contents of the file can be viewed below.

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#!/bin/sh

#set -e

Verify_checksums ()
{
	for _PARAMETER in ${LIVE_BOOT_CMDLINE}
	do
		case "${_PARAMETER}" in
			live-boot.verify-checksums=*|verify-checksums=*)
				LIVE_VERIFY_CHECKSUMS="true"
				LIVE_VERIFY_CHECKSUMS_DIGESTS="${_PARAMETER#*verify-checksums=}"
				;;

			live-boot.verify-checksums|verify-checksums)
				LIVE_VERIFY_CHECKSUMS="true"
				;;
		esac
	done

	case "${LIVE_VERIFY_CHECKSUMS}" in
		true)
			;;

		*)
			return 0
			;;
	esac

	_MOUNTPOINT="${1}"

	LIVE_VERIFY_CHECKSUMS_DIGESTS="${LIVE_VERIFY_CHECKSUMS_DIGESTS:-sha512 sha384 sha256 sha224 sha1 md5}"
	_TTY="/dev/tty8"

	log_begin_msg "Verifying checksums"

	cd "${_MOUNTPOINT}"

	for _DIGEST in $(echo ${LIVE_VERIFY_CHECKSUMS_DIGESTS} | sed -e 's|,| |g')
	do
		_CHECKSUMS="$(echo ${_DIGEST} | tr [a-z] [A-Z])SUMS ${_DIGEST}sum.txt"

		for _CHECKSUM in ${_CHECKSUMS}
		do
			if [ -e "${_CHECKSUM}" ]
			then
				echo "Found ${_CHECKSUM}..." > "${_TTY}"

				if [ -e "/bin/${_DIGEST}sum" ]
				then
					echo "Checking ${_CHECKSUM}..." > "${_TTY}"

					# Verify checksums
					/bin/${_DIGEST}sum -c "${_CHECKSUM}" < "${_TTY}" > "${_TTY}"
					_RETURN="${?}"

					# Stop after first verification
					break
				else
					echo "Not found /bin/${_DIGEST}sum..." > "${_TTY}"
				fi
			fi
		done
	done

	log_end_msg

	case "${_RETURN}" in
		0)
			log_success_msg "Verification successfull, rebooting in 10 seconds."
			sleep 10

			# Unmount live-media
			cd /
			umount -f "${_MOUNTPOINT}" > /dev/null 2>&1
			sync

			# Attempt to remount all mounted filesystems read-only
			echo u > /proc/sysrq-trigger

			# Immediately reboot the system without syncing or unmounting filesystems
			echo b > /proc/sysrq-trigger
			;;

		*)
			panic "Verification failed, $(basename ${_TTY}) for more information."
			;;
	esac
}