iankelling.org Git - distro-setup/blob - switch-mail-host

   1 #!/bin/bash
   2 # I, Ian Kelling, follow the GNU license recommendations at
   3 # https://www.gnu.org/licenses/license-recommendations.en.html. They
   4 # recommend that small programs, < 300 lines, be licensed under the
   5 # Apache License 2.0. This file contains or is part of one or more small
   6 # programs. If a small program grows beyond 300 lines, I plan to switch
   7 # its license to GPL.
   8
   9 # Copyright 2024 Ian Kelling
  10
  11 # Licensed under the Apache License, Version 2.0 (the "License");
  12 # you may not use this file except in compliance with the License.
  13 # You may obtain a copy of the License at
  14
  15 #     http://www.apache.org/licenses/LICENSE-2.0
  16
  17 # Unless required by applicable law or agreed to in writing, software
  18 # distributed under the License is distributed on an "AS IS" BASIS,
  19 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  20 # See the License for the specific language governing permissions and
  21 # limitations under the License.
  22
  23
  24 set -e; . /usr/local/lib/bash-bear; set +e
  25
  26 usage() {
  27   cat <<EOF
  28 Usage: switch-mail-host|switch-host2 [OPTIONS] push|pull HOST
  29
  30 Turn off mail receiving on OLD_HOST, run btrbk to move mail to NEW_HOST,
  31 turn on mail receiving on NEW_HOST.  Assumes we want to move all
  32 filesystems unless passing -o.
  33
  34 -a         Avoid snapshot /a, /q, and similar. If we haven't
  35            made any changes in the last hour, there is no
  36            need to snapshot anything but /o, and we will
  37            just do that once.
  38 -i         Disallow incremental backup.
  39 -o         Only btrbk /o, instead of all filesystems.
  40 --force    Run even though our local state does not say that MAIL_HOST is
  41            us when pushing or HOST when pulling.
  42 -h|--help  Print help and exit.
  43
  44 I used to adjust home network dns so NEW_HOST resolves locally if it is
  45 on the local network, but its simpler just not to and just rely
  46 on the internet. Email can wait.
  47
  48 Note: Uses GNU getopt options parsing style
  49 EOF
  50   exit 0
  51 }
  52
  53 script_name="${BASH_SOURCE[0]}"
  54 script_name="${script_name##*/}"
  55
  56 restore_new_btrbk=false
  57 restore_old_btrbk=false
  58 err-cleanup() {
  59   if $restore_new_btrbk; then
  60     e WARNING: due to failure, btrbk.timer may need manual restoration:
  61     e $new_shell systemctl start btrbk.timer
  62   fi
  63   if $restore_old_btrbk; then
  64     e WARNING: due to failure, btrbk.timer may need manual restoration:
  65     e $old_shell systemctl start btrbk.timer
  66   fi
  67 }
  68
  69 pre="$script_name:"
  70 m() { printf "$pre %s\n"  "$*"; "$@"; }
  71 e() { printf "$pre %s\n"  "$*"; }
  72 err() { echo "$pre ERROR: $*" >&2; }
  73 die() { printf "%s\n" "$*" >&2; echo "exiting with status 1" >&2; exit 1; }
  74
  75 if [[ $EUID != 0 ]]; then
  76   err "requires running as root"
  77   exit 1
  78 fi
  79
  80
  81 ##### begin command line parsing ########
  82
  83 mail_only=false
  84 host2_only=false
  85 force=false
  86 force_arg=
  87 pull_reexec=false
  88 mp_args="-m /o,/a,/q,/qd,/qr"
  89 check_installed=false
  90 orig_args=("$@")
  91 if ! temp=$(getopt -l check-installed,force,pull-reexec,help afioh "$@"); then
  92   err "args invalid. args=$*"
  93 fi
  94 eval set -- "$temp"
  95 while true; do
  96   case $1 in
  97     -a) snapshot_arg=resume ;;
  98     --force|-f)
  99       force=true
 100       force_arg=-f
 101       ;;
 102     --check-installed)
 103       check_installed=true
 104       ;;
 105     -i) incremental_arg="-i" ;;
 106     # internal option for rerunning under newer old_host when doing pull
 107     --pull-reexec) pull_reexec=true;;
 108     -o)
 109       mail_only=true ;;
 110     -h|--help) usage ;;
 111     --) shift; break ;;
 112     *) echo "$0: Internal error! unexpected args: $*" ; exit 1 ;;
 113   esac
 114   shift
 115 done
 116
 117
 118 if (( $# != 2 )) && ! $check_installed; then
 119   err expected 2 args, got $#
 120 fi
 121
 122 if [[ ! $HOSTNAME ]]; then
 123   err "\$HOSTNAME is unset"
 124   exit 1
 125 fi
 126
 127 uninstalled-file-die() {
 128   die "on host=$HOSTNAME, uninstalled file $1. run install-my-scripts or rerun with -f"
 129 }
 130
 131
 132 source /a/bin/bash_unpublished/source-state
 133
 134 direction=$1
 135 host=$2
 136
 137 case $script_name in
 138   switch-mail-host)
 139     if [[ $MAIL_HOST != "$HOST2" ]]; then
 140       mail_only=true
 141     fi
 142     ;;
 143   switch-host2)
 144     host2_only=true
 145     ;;
 146   *)
 147     err unexpected script name
 148     ;;
 149 esac
 150
 151 if $mail_only; then
 152   mp_args="-m /o"
 153 elif $host2_only; then
 154   mp_args="-m /a,/q,/qd,/qr"
 155 fi
 156
 157
 158 if ! $force && { $check_installed || [[ $direction == push ]]; } ; then
 159   install_bin_files=(
 160     mount-latest-subvol
 161     check-subvol-stale
 162     btrbk-run
 163     switch-mail-host
 164   )
 165   for f in ${install_bin_files[@]}; do
 166     if ! diff -q /a/bin/ds/$f /usr/local/bin/$f; then
 167       uninstalled-file-die $f
 168     fi
 169   done
 170   if ! diff -q /a/bin/bash-bear-trap/bash-bear /usr/local/lib/bash-bear; then
 171     uninstalled-file-die err
 172   fi
 173   if $check_installed; then
 174     exit 0
 175   fi
 176 fi
 177
 178
 179 case $direction in
 180   push)
 181     old_host=$HOSTNAME
 182     old_hostname=$HOSTNAME
 183     new_host=$host
 184     bbk_args="-t $new_host"
 185     new_shell="ssh -F $HOME/.ssh/confighome root@$new_host"
 186     if ! new_hostname=$($new_shell hostname); then
 187       echo "$pre: error: failed ssh. retrying failed $new_shell with -v for more info:"
 188       $new_shell -v hostname
 189     fi
 190     ;;
 191   pull)
 192     old_host=$host
 193     new_host=$HOSTNAME
 194     new_hostname=$HOSTNAME
 195     bbk_args="-s $old_host"
 196     old_shell="ssh -F $HOME/.ssh/confighome root@$old_host"
 197     # tests ssh connection. crafted this to not need to do escape chars
 198
 199     if ! $mail_only && ! $pull_reexec ; then
 200       if ! $force; then
 201         if ! $old_shell switch-mail-host --check-installed; then
 202           die "failed: $old_shell switch-mail-host --check-installed"
 203         fi
 204       fi
 205       tmpd=$(mktemp -d)
 206       files=(
 207         /usr/local/{bin/{unsaved-buffers{,.el},switch-mail-host},lib/bash-bear}
 208       )
 209       m scp -F $HOME/.ssh/confighome \
 210         ${files[@]/#/root@$old_host:} $tmpd
 211       diff=false
 212       for f in ${files[@]}; do
 213         if ! diff -q $tmpd/${f##*/} $f; then
 214           m install -T $tmpd/${f##*/} $f
 215           diff=true
 216         fi
 217       done
 218       if $diff; then
 219         e "found different version on old_host=$old_host, reexecing"
 220         m /usr/local/bin/switch-mail-host --pull-reexec "${orig_args[@]}"
 221         exit 0
 222       fi
 223       rm -r -- $tmpd
 224     fi
 225
 226     f=/a/bin/bash_unpublished/source-state
 227     if ! old_info=$($old_shell "hostname; sed -n s,.*MAIL_HOST=,,p $f; sed -n s,.*HOST2=,,p $f"); then
 228       echo "$pre: error: failed ssh. retrying failed $old_shell with -v for more info:"
 229       $old_shell -v hostname
 230       exit 1
 231     fi
 232     read -d '' -r old_hostname MAIL_HOST HOST2 <<<"$old_info" || (( $? == 1 ))
 233
 234     ;;
 235   *)
 236     err invalid first argument
 237     exit 1
 238     ;;
 239 esac
 240
 241
 242 if ! $force; then
 243   if $host2_only; then
 244     if [[ $old_hostname != "$HOST2" ]]; then
 245       err "\$old_hostname($old_hostname) != \$HOST2($HOST2). Rerun with --force if you really want this."
 246       exit 1
 247     fi
 248   elif [[ $old_hostname != "$MAIL_HOST" ]]; then
 249     err "\$old_hostname($old_hostname) != \$MAIL_HOST($MAIL_HOST). Rerun with --force if you really want this."
 250     exit 1
 251   fi
 252 fi
 253
 254 if [[ ! $new_host || ! $old_host ]]; then
 255   echo "$0: bad args. see script"
 256   exit 1
 257 fi
 258
 259
 260 ########### end initial processing, begin actually modifying things ##########
 261
 262 if $new_shell systemctl is-active btrbk.timer; then
 263   m $new_shell systemctl stop btrbk.timer
 264   restore_new_btrbk=true
 265 fi
 266 if $old_shell systemctl is-active btrbk.timer; then
 267   m $old_shell systemctl stop btrbk.timer
 268   restore_old_btrbk=true
 269 fi
 270
 271 btrbk_test="systemctl is-active btrbk.service"
 272 active=true
 273 while $active; do
 274   active=false
 275   for shell in "$new_shell" "$old_shell"; do
 276     e $shell $btrbk_test
 277     status=$($shell $btrbk_test) ||:
 278     case $status in
 279       inactive|failed) : ;;
 280       *)
 281         # This covers conditions like "activating", which still return 3 from
 282         # systemctl is-active.
 283         active=true
 284         e "btrbk active on shell:$shell, status:$status, sleeping 8 seconds"
 285         sleep 8
 286         break
 287         ;;
 288     esac
 289   done
 290 done
 291
 292 if ! $host2_only; then
 293   # ensure these are unused before doing anything
 294   e "On $new_host: umounting /m and /o, checking emacs"
 295   {
 296     cat /usr/local/bin/unsaved-buffers
 297     if ! $host2_only; then
 298       cat <<EOF
 299 for dir in m o; do
 300   if mountpoint -q /\$dir; then
 301     echo On $new_host: umount /\$dir
 302     umount /\$dir
 303   fi
 304 done
 305 EOF
 306     fi
 307   } | $new_shell bash -s
 308 fi
 309
 310 if ! $mail_only; then
 311   cat /usr/local/bin/unsaved-buffers - <<'EOF' |  $old_shell bash -s
 312
 313 # Try to prevent emacs from saving stale data it has in memory to disk. eg: files, recentf list, etc.
 314 # But if emacs ignores the signal, let it live.
 315 pkill -xf 'emacs( --daemon| -f znc-all)' ||:
 316
 317 if [[ -e /p/profanity-here ]]; then
 318   systemctl disable --now profanity
 319 fi
 320 EOF
 321 fi
 322
 323 # previously, I was checking to see if the new mail host
 324 # is on my home network, then changing my home dns
 325 # to resolve on the local network, so that I didnt
 326 # have to send traffic out to the internet or rely
 327 # on that. However, that breaks for a laptop that roams.
 328 # So, we could have a cronjob that updates that dns,
 329 # however, another solution is to just use ipv6,
 330 # and I prefer that.
 331 #
 332 # TODO: enable ipv6 for email. exim config setting disables it.
 333 # need to add vpn support. need to add firewall / routing.
 334 # I think exim will try ipv6 first, so no need to disable
 335 # ipv6 i think.
 336
 337
 338 e Running initial btrbk
 339 m btrbk-run -v $bbk_args $force_arg $incremental_arg $mp_args $snapshot_arg || ret=$?
 340 if (( ret )); then
 341   err "failed initial btrbk"
 342   exit $ret
 343 fi
 344
 345 if ! $mail_only; then
 346   m $old_shell sed -ri "s/HOST2=.*/HOST2=$new_hostname/" /a/bin/bash_unpublished/source-state
 347   m $new_shell sed -ri "s/HOST2=.*/HOST2=$new_hostname/" /a/bin/bash_unpublished/source-state
 348 fi
 349
 350 if $host2_only; then
 351   if [[ $old_hostname != "$MAIL_HOST" && $old_hostname != kd ]]; then
 352     m $old_shell systemctl --now disable btrbk.timer
 353   fi
 354   m $new_shell systemctl --now enable btrbk.timer
 355   if [[ -e /p/profanity-here ]]; then
 356     m $new_shell systemctl --now enable profanity
 357   fi
 358   exit 0
 359 fi
 360
 361 m $old_shell /a/exe/primary-setup $new_hostname || ret=$?
 362 if (( ret )); then
 363   err "failed \$old_shell primary-setup \$new_hostname. fix and rerun $script_name"
 364   exit $ret
 365 fi
 366
 367
 368 e Running main btrbk
 369 m btrbk-run -v --fast $bbk_args $force_arg $incremental_arg -m /o || ret=$?
 370 if (( ret )); then
 371   bang="███████"
 372   e $bang failed btrbk of /o. restoring old host as primary
 373   if ! m $old_shell /a/exe/primary-setup localhost; then
 374     die "due to failed btrbk of /o, we tried to restore old host as primary, but then we failed at that too. To resolve: Fix & rerun switch-mail-host, or fix and rerun primary-setup localhost on old shell so you have a working mail server and then rerun switch-mail-host."
 375   fi
 376   e finished restoring old host as primary, now exiting $ret due to earlier failed btrbk of /o.
 377   exit $ret
 378 fi
 379
 380 # new system is usable at this point
 381 blocks=██████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████
 382 printf "%s\n" "${blocks:0:${COLUMNS:-100}}"
 383
 384 # once I accidentally accepted incoming mail on old host. I used this script to copy over that mail:
 385 #
 386 # die=false; for d in o.leaf.2021-05-29T10:02:08-0400/m/{4e,md,4e2}/{,l/}!(*myarchive)/new; do if $die; then break; fi; find $d -type f -mtime -5 | while read -r f; do dir="${f%new/*}"; dir="btrbk/o.20210530T000011-0400/${dir#*/}"; fname="${f##*/}"; [[ -e $dir/new/$fname || -e $dir/cur/$fname ]] && continue; if ! e cp -a $f /${dir#*/*/}new; then echo failed cp; die=true; break; fi ; done; done
 387
 388 # once I accidentally sent mail from non-main mail host. to copy into the main mail host's sent dir, cd into dir of non-mail mail host Sent/cur, then
 389 #
 390 # shopt -s nullglob; find . -type f -mtime -2 | while read -r f; do a=( /m/4e/Sent/cur/${f%,*}* ); if (( ${#a[@]} )); then e exists $a; else m cp -a $f /m/4e/Sent/cur; fi; done
 391
 392 m $new_shell /a/exe/primary-setup localhost || ret=$?
 393 if (( ret )); then
 394   err "failed final primary-setup, just fix and rerun: $new_shell /a/exe/primary-setup localhost"
 395   exit $ret
 396 fi
 397
 398 m exit 0