This file is indexed.

/usr/sbin/update-initramfs is in initramfs-tools 0.99ubuntu13.5.

This file is owned by root:root, with mode 0o755.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
#!/bin/sh

STATEDIR=/var/lib/initramfs-tools
BOOTDIR=/boot
CONF=/etc/initramfs-tools/update-initramfs.conf
USETRIGGERS=true
mode=""
version=""
update_initramfs=yes
backup_initramfs=no

set -e

[ -r ${CONF} ] && . ${CONF}

case "$DPKG_MAINTSCRIPT_PACKAGE" in
linux-image-*)
	if [ -z "$INITRAMFS_TOOLS_KERNEL_HOOK" ]; then
		# kernel maintainer script called us directly; ignore
		# it and let the hook script handle it instead
		echo "update-initramfs: deferring update (hook will be called later)"
		exit 0
	fi
	;;
?*)
	if	   $USETRIGGERS						\
		&& [ $# = 1 ]						\
		&& [ x"$1" = x-u ]					\
		&& dpkg-trigger --check-supported 2>/dev/null
	then
		if dpkg-trigger --no-await update-initramfs; then
			echo "update-initramfs: deferring update (trigger activated)"
			exit 0
		fi
	fi
	;;
esac

usage()
{
	if [ -n "${1:-}" ]; then
		printf "${*}\n\n" >&2
	fi
	cat >&2 << EOF
Usage: ${0} [OPTION]...

Options:
 -k [version]	Specify kernel version or 'all'
 -c		Create a new initramfs
 -u		Update an existing initramfs
 -d		Remove an existing initramfs
 -t		Take over a custom initramfs with this one
 -b		Set alternate boot directory
 -v		Be verbose
 -h		This message

EOF
	exit 1
}

# chroot check
chrooted()
{
	# borrowed from udev's postinst
	if [ "$(stat -c %d/%i /)" = "$(stat -Lc %d/%i /proc/1/root 2>/dev/null)" ]; then
		# the devicenumber/inode pair of / is the same as that of
		# /sbin/init's root, so we're *not* in a chroot and hence
		# return false.
		return 1
	fi
return 0
}

mild_panic()
{
	if [ -n "${1:-}" ]; then
		printf "${*}\n" >&2
	fi
	exit 0
}

panic()
{
	if [ -n "${1:-}" ]; then
		printf "${*}\n" >&2
	fi
	exit 1
}

verbose()
{
	if [ "${verbose}" = 1 ]; then
		printf "${*}\n"
	fi
}

version_exists()
{
	[ -e "${STATEDIR}/${1}" ] && [ -e "${initramfs}" ]
	return $?
}

set_initramfs()
{
	initramfs="${BOOTDIR}/initrd.img-${version}"
}


# backup initramfs while running
backup_initramfs()
{
	[ ! -r "${initramfs}" ] && return 0
	initramfs_bak="${initramfs}.dpkg-bak"
	[ -r "${initramfs_bak}" ] && rm -f "${initramfs_bak}"
	ln -f "${initramfs}" "${initramfs_bak}" \
		|| cp -a "${initramfs}" "${initramfs_bak}"
	verbose "Keeping ${initramfs_bak}"
}

# keep booted initramfs
backup_booted_initramfs()
{
	initramfs_bak="${initramfs}.dpkg-bak"

	# first time run thus no backup
	[ ! -r "${initramfs_bak}" ] && return 0

	# chroot with no /proc
	[ ! -r /proc/uptime ] && rm -f "${initramfs_bak}" && return 0

	# no kept backup wanted
	[ "${backup_initramfs}" = "no" ] && rm -f "${initramfs_bak}" && return 0

	# no backup yet
	if [ ! -r "${initramfs}.bak" ]; then
		mv -f ${initramfs_bak} "${initramfs}.bak"
		verbose "Backup ${initramfs}.bak"
		return 0
	fi

	# keep booted initramfs
	boot_initramfs=
	uptime_days=$(awk '{printf "%d", $1 / 3600 / 24}' /proc/uptime)
	if [ -n "$uptime_days" ]; then
		boot_initramfs=$(find "${initramfs}.bak" -mtime +${uptime_days})
	fi
	if [ -n "${boot_initramfs}" ]; then
		mv -f "${initramfs_bak}" "${initramfs}.bak"
		verbose "Backup ${initramfs}.bak"
		return 0
	fi
	verbose "Removing current backup ${initramfs_bak}"
	rm -f ${initramfs_bak}
}

# nuke generated copy
remove_initramfs_bak()
{
	[ -z "${initramfs_bak:-}" ] && return 0
	rm -f "${initramfs_bak}"
	verbose "Removing ${initramfs_bak}"
}


generate_initramfs()
{
	echo "update-initramfs: Generating ${initramfs}"
	OPTS="-o"
	if [ "${verbose}" = 1 ]; then
		OPTS="-v ${OPTS}"
	fi
	if mkinitramfs ${OPTS} "${initramfs}.new" "${version}"; then
		mv -f "${initramfs}.new" "${initramfs}"
		set_sha1
	else
		mkinitramfs_return="$?"
		remove_initramfs_bak
		rm -f "${initramfs}.new"
		if [ "$mkinitramfs_return" = "2" ]; then
			# minversion wasn't met, exit 0
			exit 0
		fi
		echo "update-initramfs: failed for ${initramfs} with $mkinitramfs_return." >&2
		exit $mkinitramfs_return
	fi
}

# lilo call
run_lilo()
{
	# show lilo errors on failure
	if ! lilo -t  > /dev/null 2>&1 ; then
		echo "ERROR lilo fails for new ${initramfs}:" >&2
		echo
		lilo -t
	fi
	lilo
}

# Invoke bootloader
run_bootloader()
{
	# invoke policy conformant bootloader hooks
	if [ -d /etc/initramfs/post-update.d/ ]; then
		run-parts --arg=${version} --arg=${initramfs} \
			/etc/initramfs/post-update.d/
		return 0
	fi
}

compare_sha1()
{
	sha1sum "${initramfs}" | diff "${STATEDIR}/${version}" - >/dev/null 2>&1
	return $?
}

# Note that this must overwrite so that updates work.
set_sha1()
{
	sha1sum "${initramfs}" > "${STATEDIR}/${version}"
}

delete_sha1()
{
	rm -f "${STATEDIR}/${version}"
}

# ro /boot is not modified
ro_boot_check()
{
	# check irrelevant inside of a chroot
	if [ ! -r /proc/mounts ] || chrooted; then
		return 0
	fi

	boot_opts=$(awk '/boot/{if ((match($4, /^ro/) || match($4, /,ro/)) \
		&& $2 == "/boot") print "ro"}' /proc/mounts)
	if [ -n "${boot_opts}" ]; then
		echo "WARNING: /boot is ro mounted."
		echo "update-initramfs: Not updating ${initramfs}"
		exit 0
	fi
}

get_sorted_versions()
{
	version_list=""

	for gsv_x in "${STATEDIR}"/*; do
		gsv_x="$(basename "${gsv_x}")"
		if [ "${gsv_x}" = '*' ]; then
			return 0
		fi
		worklist=""
		for gsv_i in $version_list; do
			if dpkg --compare-versions "${gsv_x}" '>' "${gsv_i}"; then
				worklist="${worklist} ${gsv_x} ${gsv_i}"
				gsv_x=""
			else
				worklist="${worklist} ${gsv_i}"
			fi
		done
		if [ "${gsv_x}" != "" ]; then
			worklist="${worklist} ${gsv_x}"
		fi
		version_list="${worklist}"
	done

	verbose "Available versions: ${version_list}"
}

set_current_version()
{
	if [ -f /boot/initrd.img-`uname -r` ]; then
		version=`uname -r`
	fi
}

set_linked_version()
{
	linktarget=
	if [ -e /initrd.img ] && [ -L /initrd.img ]; then
		linktarget="$(basename "$(readlink /initrd.img)")"
	fi

	if [ -e /boot/initrd.img ] && [ -L /boot/initrd.img ]; then
		linktarget="$(basename "$(readlink /boot/initrd.img)")"
	fi

	if [ -z "${linktarget}" ]; then
		return
	fi

	version="${linktarget##initrd.img-}"
}

set_highest_version()
{
	get_sorted_versions
	if [ -z "${version_list}" ]; then
		version=
		return
	fi
	set -- ${version_list}
	version=${1}
}

create()
{
	if [ -z "${version}" ]; then
		usage "Create mode requires a version argument"
	fi

	set_initramfs

	if [ "${takeover}" = 0 ]; then
		if version_exists "${version}"; then
			panic "Cannot create version ${version}: already exists"
		fi

		if [ -e "${initramfs}" ]; then
			panic "${initramfs} already exists, cannot create."
		fi
	fi

	generate_initramfs
}

update()
{
	if [ "${update_initramfs}" = "no" ]; then
		echo "update-initramfs: Not updating initramfs."
		exit 0
	fi

	if [ -z "${version}" ]; then
		set_highest_version
	fi

	if [ -z "${version}" ]; then
		set_linked_version
	fi

	if [ -z "${version}" ]; then
		set_current_version
	fi

	if [ -z "${version}" ]; then
		verbose "Nothing to do, exiting."
		exit 0
	fi

	set_initramfs

	ro_boot_check

	altered_check

	backup_initramfs

	generate_initramfs

	run_bootloader

	backup_booted_initramfs
}

delete()
{
	if [ -z "${version}" ]; then
		usage "Delete mode requires a version argument"
	fi

	set_initramfs

	if [ "${takeover}" = 0 ]; then
		if [ ! -e "${initramfs}" ]; then
			panic "Cannot delete ${initramfs}, doesn't exist."
		fi

		if ! version_exists "${version}"; then
			panic "Cannot delete version ${version}: Not created by this utility."
		fi
	fi

	altered_check

	echo "update-initramfs: Deleting ${initramfs}"

	delete_sha1

	rm -f "${initramfs}" "${initramfs}.bak"
}

# Check for update mode on existing and modified initramfs
altered_check()
{
	# No check on takeover
	[ "${takeover}" = 1 ] && return 0
	if [ ! -e "${initramfs}" ]; then
		mild_panic "${initramfs} does not exist. Cannot update."
	fi
	if ! compare_sha1; then
		echo "update-initramfs: ${initramfs} has been altered." >&2
		mild_panic "update-initramfs: Cannot update. Override with -t option."
	fi
}

# Defaults
verbose=0
yes=0
# We default to takeover=1 in Ubuntu, but not Debian
takeover=1

##

while getopts "k:cudyvtb:h?" flag; do
	case "${flag}" in
	k)
		version="${OPTARG}"
		;;
	c)
		mode="c"
		;;
	d)
		mode="d"
		;;
	u)
		mode="u"
		;;
	v)
		verbose="1"
		;;
	y)
		yes="1"
		;;
	t)
		takeover="1"
		;;
	b)
		BOOTDIR="${OPTARG}"
		if [ ! -d "${BOOTDIR}" ]; then
			echo "Error: ${BOOTDIR} is not a directory." >&2
			exit 1
		fi
		;;
	h|?)
		usage
		;;
	esac
done

shift $((${OPTIND} - 1))

if [ $# -ne 0 ]; then
	echo "Invalid argument for option -k." >&2
	usage
fi

# Validate arguments
if [ -z "${mode}" ]; then
	usage "You must specify at least one of -c, -u, or -d."
fi

if [ "${version}" = "all" ] \
	|| ( [ "${update_initramfs}" = "all" ] && [ -z "${version}" ] ); then
	: FIXME check for --yes, and if not ask are you sure
	get_sorted_versions
	if [ -z "${version_list}" ]; then
		verbose "Nothing to do, exiting."
		exit 0
	fi

	OPTS="-b ${BOOTDIR}"
	if [ "${verbose}" = "1" ]; then
		OPTS="${OPTS} -v"
	fi
	if [ "${takeover}" = "1" ]; then
		OPTS="${OPTS} -t"
	fi
	if [ "${yes}" = "1" ]; then
		OPTS="${OPTS} -y"
	fi
	for u_version in ${version_list}; do
		verbose "Execute: ${0} -${mode} -k \"${u_version}\" ${OPTS}"
		"${0}" -${mode} -k "${u_version}" ${OPTS}
	done
	exit 0
fi


case "${mode}" in
	c)
		create
		;;
	d)
		delete
		;;
	u)
		update
		;;
esac