summaryrefslogtreecommitdiff
path: root/usr.sbin/sysmerge/sysmerge.sh
blob: 28d3e856a663eb3f01d280bd34a44c9bab1af853 (plain)
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
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
#!/bin/ksh -
#
# $OpenBSD: sysmerge.sh,v 1.228 2016/09/22 13:08:20 ajacoutot Exp $
#
# Copyright (c) 2008-2014 Antoine Jacoutot <ajacoutot@openbsd.org>
# Copyright (c) 1998-2003 Douglas Barton <DougB@FreeBSD.org>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#

umask 0022

usage() {
	echo "usage: ${0##*/} [-bdp]" >&2 && exit 1
}

# OpenBSD /etc/rc v1.456
stripcom() {
	local _file=$1 _line

	[[ -s $_file ]] || return

	while read _line ; do
		_line=${_line%%#*}
		[[ -n $_line ]] && print -r -- "$_line"
	done <$_file
}

sm_error() {
	(($#)) && echo "!!!! $@"
	rm -rf ${_TMPROOT}
	exit 1
}

sm_trap() {
	rm -f /var/sysmerge/{etc,pkg,xetc}sum
	sm_error
}

trap "sm_trap" 1 2 3 13 15

sm_info() {
	(($#)) && echo "---- $@" || true
}

sm_warn() {
	(($#)) && echo "**** $@" || true
}

sm_extract_sets() {
	${PKGMODE} && return
	local _e _x _set

	[[ -f /var/sysmerge/etc.tgz ]] && _e=etc
	[[ -f /var/sysmerge/xetc.tgz ]] && _x=xetc
	[[ -z ${_e}${_x} ]] && sm_error "cannot find sets to extract"

	for _set in ${_e} ${_x}; do
		tar -xzphf \
			/var/sysmerge/${_set}.tgz || \
			sm_error "failed to extract ${_set}.tgz"
	done
}

sm_rotate_bak() {
	local _b

	for _b in $(jot 4 3 0); do
		[[ -d ${_BKPDIR}.${_b} ]] && \
			mv ${_BKPDIR}.${_b} ${_BKPDIR}.$((_b+1))
	done
	rm -rf ${_BKPDIR}.4
	[[ -d ${_BKPDIR} ]] && mv ${_BKPDIR} ${_BKPDIR}.0
	# make sure this function is only run _once_ per sysmerge invocation
	unset -f sm_rotate_bak
}

# get pkg @sample information
exec_espie() {
	local _tmproot

	_tmproot=${_TMPROOT} /usr/bin/perl <<'EOF'
use strict;
use warnings;

package OpenBSD::PackingElement;

sub walk_sample
{
}

package OpenBSD::PackingElement::Sampledir;
sub walk_sample
{
	my $item = shift;
	print "0-DIR", " ",
	      $item->{owner} // "root", " ",
	      $item->{group} // "wheel", " ",
	      $item->{mode} // "0755", " ",
	      $ENV{'_tmproot'}, $item->fullname,
	      "\n";
}

package OpenBSD::PackingElement::Sample;
sub walk_sample
{
	my $item = shift;
	print "1-FILE", " ",
	      $item->{owner} // "root", " ",
	      $item->{group} // "wheel", " ",
	      $item->{mode} // "0644", " ",
	      $item->{copyfrom}->fullname, " ",
	      $ENV{'_tmproot'}, $item->fullname,
	      "\n";
}

package main;
use OpenBSD::PackageInfo;
use OpenBSD::PackingList;

for my $i (installed_packages()) {
	my $plist = OpenBSD::PackingList->from_installation($i);
	$plist->walk_sample();
}
EOF
}

sm_cp_pkg_samples() {
	! ${PKGMODE} && return
	local _install_args _i _ret=0 _sample

	# access to full base system hierarchy is implied in packages
	mtree -qdef /etc/mtree/4.4BSD.dist -U >/dev/null
	mtree -qdef /etc/mtree/BSD.x11.dist -U >/dev/null

	# @sample directories are processed first
	exec_espie | sort -u | while read _i; do
		set -A _sample -- ${_i}
		_install_args="-o ${_sample[1]} -g ${_sample[2]} -m ${_sample[3]}"
		if [[ ${_sample[0]} == "0-DIR" ]]; then
			install -d ${_install_args} ${_sample[4]} || _ret=1
		else
			# directory we want to copy the @sample file into
			# does not exist and is not a @sample so we have no
			# knowledge of the required owner/group/mode
			# (e.g. /var/www/usr/sbin in mail/femail,-chroot)
			_pkghier=${_sample[5]%/*}
			if [[ ! -d ${_pkghier#${_TMPROOT}} ]]; then
				sm_warn "skipping ${_sample[5]#${_TMPROOT}}: ${_pkghier#${_TMPROOT}} does not exist"
				continue
			else
				# non-default prefix (e.g. mail/roundcubemail)
				install -d ${_pkghier}
			fi
			install ${_install_args} \
				${_sample[4]} ${_sample[5]} || _ret=1
		fi
	done

	if [[ ${_ret} -eq 0 ]]; then
		find . -type f -exec sha256 '{}' + | sort \
			>./var/sysmerge/pkgsum || _ret=1
	fi
	[[ ${_ret} -ne 0 ]] && \
		sm_error "failed to populate packages @samples and create sum file"
}

sm_run() {
	local _auto_upg _c _c1 _c2 _cursum _diff _i _k _j _cfdiff _cffiles
	local _ignorefiles _cvsid1 _cvsid2 _matchsum _mismatch

	# XXX remove after OPENBSD_6_1
	rm -f /var/sysmerge/examplessum

	sm_extract_sets
	sm_add_user_grp
	sm_cp_pkg_samples

	for _i in etcsum xetcsum pkgsum; do
		if [[ -f /var/sysmerge/${_i} && \
			-f ./var/sysmerge/${_i} ]] && \
			! ${DIFFMODE}; then
			# redirect stderr: file may not exist
			_matchsum=$(sha256 -c /var/sysmerge/${_i} 2>/dev/null | \
				sed -n 's/^(SHA256) \(.*\): OK$/\1/p')
			# delete file in temproot if it has not changed since
			# last release and is present in current installation
			for _j in ${_matchsum}; do
				# skip sum files
				[[ ${_j} == ./var/sysmerge/${_i} ]] && continue
				[[ -f ${_j#.} && -f ${_j} ]] && \
					rm ${_j}
			done

			# set auto-upgradable files
			_mismatch=$(diff -u ./var/sysmerge/${_i} /var/sysmerge/${_i} | \
				sed -n 's/^+SHA256 (\(.*\)).*/\1/p')
			for _k in ${_mismatch}; do
				# skip sum files
				[[ ${_k} == ./var/sysmerge/${_i} ]] && continue
				# compare CVS Id first so if the file hasn't been modified,
				# it will be deleted from temproot and ignored from comparison;
				# several files are generated from scripts so CVS ID is not a
				# reliable way of detecting changes: leave for a full diff
				if ! ${PKGMODE} && \
					[[ ${_k} != ./etc/@(fbtab|ttys) && \
					! -h ${_k} ]]; then
					_cvsid1=$(sed -n "/[$]OpenBSD:.*Exp [$]/{p;q;}" ${_k#.} 2>/dev/null)
					_cvsid2=$(sed -n "/[$]OpenBSD:.*Exp [$]/{p;q;}" ${_k} 2>/dev/null)
					[[ -n ${_cvsid1} ]] && \
						[[ ${_cvsid1} == ${_cvsid2} ]] && \
						[[ -f ${_k} ]] && rm ${_k} && \
						continue
				fi
				# redirect stderr: file may not exist
				_cursum=$(cd / && sha256 ${_k} 2>/dev/null)
				grep -q "${_cursum}" /var/sysmerge/${_i} && \
					! grep -q "${_cursum}" ./var/sysmerge/${_i} && \
					_auto_upg="${_auto_upg} ${_k}"
			done
			[[ -n ${_auto_upg} ]] && set -A AUTO_UPG -- ${_auto_upg}
		fi
		[[ -f ./var/sysmerge/${_i} ]] && \
			mv ./var/sysmerge/${_i} /var/sysmerge/${_i}
	done

	# files we don't want/need to deal with
	_ignorefiles="/etc/group
		      /etc/localtime
		      /etc/master.passwd
		      /etc/motd
		      /etc/passwd
		      /etc/pwd.db
		      /etc/spwd.db
		      /var/db/locate.database
		      /var/mail/root"
	# in case X(7) is not installed, xetcsum is not removed by the loop above
	_ignorefiles="${_ignorefiles} /var/sysmerge/xetcsum"
	[[ -f /etc/sysmerge.ignore ]] && \
		_ignorefiles="${_ignorefiles} $(stripcom /etc/sysmerge.ignore)"
	for _i in ${_ignorefiles}; do
		rm -f ./${_i}
	done

	# aliases(5) needs to be handled last in case mailer.conf(5) changes
	_c1=$(find . -type f -or -type l | grep -v '^./etc/mail/aliases$')
	[[ -f ./etc/mail/aliases ]] && _c2="./etc/mail/aliases"
	for COMPFILE in ${_c1} ${_c2}; do
		IS_BIN=false
		IS_LINK=false
		TARGET=${COMPFILE#.}

		# links need to be treated in a different way
		if [[ -h ${COMPFILE} ]]; then
			IS_LINK=true
			[[ -h ${TARGET} && \
				$(readlink ${COMPFILE}) == $(readlink ${TARGET}) ]] && \
				rm ${COMPFILE} && continue
		elif [[ -f ${TARGET} ]]; then
			# empty files = binaries (to avoid comparison);
			# only process them if they don't exist on the system
			if [[ ! -s ${COMPFILE} ]]; then
				rm ${COMPFILE} && continue
			fi

			_diff=$(diff -q ${TARGET} ${COMPFILE} 2>&1)
			# files are the same: delete
			[[ $? -eq 0 ]] && rm ${COMPFILE} && continue
			# disable sdiff for binaries
			echo "${_diff}" | head -1 | grep -q "Binary files" && \
				IS_BIN=true
		else
			# missing files = binaries (to avoid comparison)
			IS_BIN=true
		fi

		sm_diff_loop
	done
}

sm_install() {
	local _dmode _fgrp _fmode _fown
	local _instdir=${TARGET%/*}
	[[ -z ${_instdir} ]] && _instdir="/"

	_dmode=$(stat -f "%OMp%OLp" .${_instdir}) || return
	eval $(stat -f "_fmode=%OMp%OLp _fown=%Su _fgrp=%Sg" ${COMPFILE}) || return

	if [[ ! -d ${_instdir} ]]; then
		install -d -o root -g wheel -m ${_dmode} "${_instdir}" || return
	fi

	if ${IS_LINK}; then
		_linkt=$(readlink ${COMPFILE})
		(cd ${_instdir} && ln -sf ${_linkt} . && rm ${_TMPROOT}/${COMPFILE})
		return
	fi

	if [[ -f ${TARGET} ]]; then
		if typeset -f sm_rotate_bak >/dev/null; then
			sm_rotate_bak || return
		fi
		mkdir -p ${_BKPDIR}/${_instdir} || return
		cp -p ${TARGET} ${_BKPDIR}/${_instdir} || return
	fi

	if ! install -m ${_fmode} -o ${_fown} -g ${_fgrp} ${COMPFILE} ${_instdir}; then
		rm ${_BKPDIR}/${COMPFILE} && return 1
	fi
	rm ${COMPFILE}

	case ${TARGET} in
	/etc/login.conf)
		if [[ -f /etc/login.conf.db ]]; then
			echo " (running cap_mkdb(1), needs a relog)"
			sm_warn $(cap_mkdb /etc/login.conf 2>&1)
		else
			echo
		fi
		;;
	/etc/mail/aliases)
		if [[ -f /etc/mail/aliases.db ]]; then
			echo " (running newaliases(8))"
			sm_warn $(newaliases 2>&1 >/dev/null)
		else
			echo
		fi
		;;
	*)
		echo
		;;
	esac
}

sm_add_user_grp() {
	local _g _p _gid _u _rest
	local _gr=./etc/group
	local _pw=./etc/master.passwd

	${PKGMODE} && return

	while IFS=: read -r -- _g _p _gid _rest; do
		if ! grep -Eq "^${_g}:" /etc/group; then
			getent group ${_gid} >/dev/null && \
				sm_warn "Not adding group ${_g}, GID ${_gid} already exists" && \
				continue
			echo "===> Adding the ${_g} group"
			groupadd -g ${_gid} ${_g}
		fi
	done <${_gr}

	while IFS=: read -r -- _u _p _uid _rest; do
		if [[ ${_u} != root ]]; then
			if ! grep -Eq "^${_u}:" /etc/master.passwd; then
				getent passwd ${_uid} >/dev/null && \
					sm_warn "Not adding user ${_u}, UID ${_uid} already exists" && \
					continue
				echo "===> Adding the ${_u} user"
				chpass -a "${_u}:${_p}:${_uid}:${_rest}"
			fi
		fi
	done <${_pw}
}

sm_warn_valid() {
	# done as a separate function to print a warning with the
	# filename above output from the check command
	local _res

	_res=$(eval $* 2>&1)
	if [[ $? -ne 0 || -n ${_res} ]]; then
	       sm_warn "${_file} appears to be invalid"
	       echo "${_res}"
	fi
}

sm_check_validity() {
	local _file=$1.merged
	local _fail

	case $1 in
	./etc/ssh/sshd_config)
		sm_warn_valid sshd -f ${_file} -t ;;
	./etc/pf.conf)
		sm_warn_valid pfctl -nf ${_file} ;;
	./etc/login.conf)
		sm_warn_valid "cap_mkdb -f ${_TMPROOT}/login.conf.check ${_file} || true"
		rm -f ${_TMPROOT}/login.conf.check.db ;;
	esac
}

sm_merge_loop() {
	local _instmerged _tomerge
	echo "===> Type h at the sdiff prompt (%) to get usage help\n"
	_tomerge=true
	while ${_tomerge}; do
		cp -p ${COMPFILE} ${COMPFILE}.merged
		sdiff -as -w $(tput -T ${TERM:=vt100} cols) -o ${COMPFILE}.merged \
			${TARGET} ${COMPFILE}
		_instmerged=v
		while [[ ${_instmerged} == v ]]; do
			echo
			echo "  Use 'e' to edit the merged file"
			echo "  Use 'i' to install the merged file"
			echo "  Use 'n' to view a diff between the merged and new files"
			echo "  Use 'o' to view a diff between the old and merged files"
			echo "  Use 'r' to re-do the merge"
			echo "  Use 'v' to view the merged file"
			echo "  Use 'x' to delete the merged file and go back to previous menu"
			echo "  Default is to leave the temporary file to deal with by hand"
			echo
			sm_check_validity ${COMPFILE}
			echo -n "===> How should I deal with the merged file? [Leave it for later] "
			read _instmerged
			case ${_instmerged} in
			[eE])
				echo "editing merged file...\n"
				${EDITOR} ${COMPFILE}.merged
				_instmerged=v
				;;
			[iI])
				mv ${COMPFILE}.merged ${COMPFILE}
				echo -n "\n===> Merging ${TARGET}"
				sm_install || \
					(echo && sm_warn "problem merging ${TARGET}")
				_tomerge=false
				;;
			[nN])
				(
					echo "comparison between merged and new files:\n"
					diff -u ${COMPFILE}.merged ${COMPFILE}
				) | ${PAGER}
				_instmerged=v
				;;
			[oO])
				(
					echo "comparison between old and merged files:\n"
					diff -u ${TARGET} ${COMPFILE}.merged
				) | ${PAGER}
				_instmerged=v
				;;
			[rR])
				rm ${COMPFILE}.merged
				;;
			[vV])
				${PAGER} ${COMPFILE}.merged
				;;
			[xX])
				rm ${COMPFILE}.merged
				return 1
				;;
			'')
				_tomerge=false
				;;
			*)
				echo "invalid choice: ${_instmerged}"
				_instmerged=v
				;;
			esac
		done
	done
}

sm_diff_loop() {
	local i _handle _nonexistent

	${BATCHMODE} && _handle=todo || _handle=v

	FORCE_UPG=false
	_nonexistent=false
	while [[ ${_handle} == @(v|todo) ]]; do
		if [[ -f ${TARGET} && -f ${COMPFILE} ]] && ! ${IS_LINK}; then
			if ! ${DIFFMODE}; then
				# automatically install files if current != new
				# and current = old
				for i in ${AUTO_UPG[@]}; do \
					[[ ${i} == ${COMPFILE} ]] && FORCE_UPG=true
				done
				# automatically install files which differ
				# only by CVS Id or that are binaries
				if [[ -z $(diff -q -I'[$]OpenBSD:.*$' ${TARGET} ${COMPFILE}) ]] || \
					${FORCE_UPG} || ${IS_BIN}; then
					echo -n "===> Updating ${TARGET}"
					sm_install || \
						(echo && sm_warn "problem updating ${TARGET}")
					return
				fi
			fi
			if [[ ${_handle} == v ]]; then
				(
					echo "\n========================================================================\n"
					echo "===> Displaying differences between ${COMPFILE} and installed version:"
					echo
					diff -u ${TARGET} ${COMPFILE}
				) | ${PAGER}
				echo
			fi
		else
			# file does not exist on the target system
			if ${DIFFMODE}; then
				_nonexistent=true
				${BATCHMODE} || echo "\n===> Missing ${TARGET}\n"
			elif ${IS_LINK}; then
				echo "===> Linking ${TARGET}"
				sm_install || \
					sm_warn "problem creating ${TARGET} link"
				return
			else
				echo -n "===> Installing ${TARGET}"
				sm_install || \
					(echo && sm_warn "problem installing ${TARGET}")
				return
			fi
		fi

		if ! ${BATCHMODE}; then
			echo "  Use 'd' to delete the temporary ${COMPFILE}"
			echo "  Use 'i' to install the temporary ${COMPFILE}"
			if ! ${_nonexistent} && ! ${IS_BIN} && \
				! ${IS_LINK}; then
				echo "  Use 'm' to merge the temporary and installed versions"
				echo "  Use 'v' to view the diff results again"
			fi
			echo
			echo "  Default is to leave the temporary file to deal with by hand"
			echo
			echo -n "How should I deal with this? [Leave it for later] "
			read _handle
		else
			unset _handle
		fi

		case ${_handle} in
		[dD])
			rm ${COMPFILE}
			echo "\n===> Deleting ${COMPFILE}"
			;;
		[iI])
			echo
			if ${IS_LINK}; then
				echo "===> Linking ${TARGET}"
				sm_install || \
					sm_warn "problem creating ${TARGET} link"
			else
				echo -n "===> Updating ${TARGET}"
				sm_install || \
					(echo && sm_warn "problem updating ${TARGET}")
			fi
			;;
		[mM])
			if ! ${_nonexistent} && ! ${IS_BIN} && ! ${IS_LINK}; then
				sm_merge_loop || _handle=todo
			else
				echo "invalid choice: ${_handle}\n"
				_handle=todo
			fi
			;;
		[vV])
			if ! ${_nonexistent} && ! ${IS_BIN} && ! ${IS_LINK}; then
				_handle=v
			else
				echo "invalid choice: ${_handle}\n"
				_handle=todo
			fi
			;;
		'')
			echo -n
			;;
		*)
			echo "invalid choice: ${_handle}\n"
			_handle=todo
			continue
			;;
		esac
	done
}

sm_post() {
	local _f

	cd ${_TMPROOT} && \
		find . -type d -depth -empty -exec rmdir -p '{}' + 2>/dev/null
	rmdir ${_TMPROOT} 2>/dev/null

	if [[ -d ${_TMPROOT} ]]; then
		for _f in $(find ${_TMPROOT} ! -type d ! -name \*.merged -size +0)
		do
			sm_info "${_f##*${_TMPROOT}} unhandled, re-run ${0##*/} to merge the new version"
			! ${DIFFMODE} && [[ -f ${_f} ]] && \
				sed -i "/$(sha256 -q ${_f})/d" /var/sysmerge/*sum
		done
	fi

	mtree -qdef /etc/mtree/4.4BSD.dist -p / -U >/dev/null
	[[ -d /etc/X11 ]] && \
		mtree -qdef /etc/mtree/BSD.x11.dist -p / -U >/dev/null
}

BATCHMODE=false
DIFFMODE=false
PKGMODE=false

while getopts bdp arg; do
	case ${arg} in
	b)	BATCHMODE=true;;
	d)	DIFFMODE=true;;
	p)	PKGMODE=true;;
	*)	usage;;
	esac
done
shift $(( OPTIND -1 ))
[[ $# -ne 0 ]] && usage

[[ $(id -u) -ne 0 ]] && echo "${0##*/}: need root privileges" && usage

# global constants
_BKPDIR=/var/sysmerge/backups
_RELINT=$(uname -r | tr -d '.') || exit 1
_TMPROOT=$(mktemp -d -p /tmp sysmerge.XXXXXXXXXX) || exit 1
readonly _BKPDIR _RELINT _TMPROOT

[[ -z ${VISUAL} ]] && EDITOR=${EDITOR:=/usr/bin/vi} || EDITOR=${VISUAL}
PAGER=${PAGER:=/usr/bin/more}

mkdir -p ${_TMPROOT} || sm_error "cannot create ${_TMPROOT}"
cd ${_TMPROOT} || sm_error "cannot enter ${_TMPROOT}"

sm_run && sm_post