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
 138 if ! $force && { $check_installed || [[ $direction == push ]]; } ; then
 139   install_bin_files=(
 140     mount-latest-subvol
 141     check-subvol-stale
 142     btrbk-run
 143     switch-mail-host
 144   )
 145   for f in ${install_bin_files[@]}; do
 146     if ! diff -q /a/bin/ds/$f /usr/local/bin/$f; then
 147       uninstalled-file-die $f
 148     fi
 149   done
 150   if ! diff -q /a/bin/bash-bear-trap/bash-bear /usr/local/lib/bash-bear; then
 151     uninstalled-file-die err
 152   fi
 153   if $check_installed; then
 154     exit 0
 155   fi
 156 fi
 157
 158
 159 case $direction in
 160   push)
 161     old_host=$HOSTNAME
 162     old_hostname=$HOSTNAME
 163     new_host=$host
 164     bbk_args="-t $new_host"
 165     new_shell="ssh -F $HOME/.ssh/confighome root@$new_host"
 166     if ! new_hostname=$($new_shell hostname); then
 167       echo "$pre: error: failed ssh. retrying failed $new_shell with -v for more info:"
 168       $new_shell -v hostname
 169     fi
 170     ;;
 171   pull)
 172     old_host=$host
 173     new_host=$HOSTNAME
 174     new_hostname=$HOSTNAME
 175     bbk_args="-s $old_host"
 176     old_shell="ssh -F $HOME/.ssh/confighome root@$old_host"
 177     # tests ssh connection. crafted this to not need to do escape chars
 178
 179     if ! $mail_only && ! $pull_reexec ; then
 180       if ! $force; then
 181         if ! $old_shell switch-mail-host --check-installed; then
 182           die "failed: $old_shell switch-mail-host --check-installed"
 183         fi
 184       fi
 185       tmpd=$(mktemp -d)
 186       files=(
 187         /usr/local/{bin/{unsaved-buffers{,.el},switch-mail-host},lib/bash-bear}
 188       )
 189       m scp -F $HOME/.ssh/confighome \
 190         ${files[@]/#/root@$old_host:} $tmpd
 191       diff=false
 192       for f in ${files[@]}; do
 193         if ! diff -q $tmpd/${f##*/} $f; then
 194           m install -T $tmpd/${f##*/} $f
 195           diff=true
 196         fi
 197       done
 198       if $diff; then
 199         e "found different version on old_host=$old_hostname, reexecing"
 200         m /usr/local/bin/switch-mail-host --pull-reexec "${orig_args[@]}"
 201         exit 0
 202       fi
 203       rm -r -- $tmpd
 204     fi
 205
 206     f=/a/bin/bash_unpublished/source-state
 207     if ! old_info=$($old_shell "hostname; sed -n s,.*MAIL_HOST=,,p $f; sed -n s,.*HOST2=,,p $f"); then
 208       echo "$pre: error: failed ssh. retrying failed $old_shell with -v for more info:"
 209       $old_shell -v hostname
 210       exit 1
 211     fi
 212     read -d '' -r old_hostname MAIL_HOST HOST2 <<<"$old_info" || (( $? == 1 ))
 213
 214     ;;
 215   *)
 216     err invalid first argument
 217     exit 1
 218     ;;
 219 esac
 220
 221 case $script_name in
 222   switch-mail-host)
 223     if [[ $MAIL_HOST != "$HOST2" ]]; then
 224       mail_only=true
 225     fi
 226     ;;
 227   switch-host2)
 228     host2_only=true
 229     ;;
 230   *)
 231     err unexpected script name
 232     ;;
 233 esac
 234
 235 if $mail_only; then
 236   mp_args="-m /o"
 237 elif $host2_only; then
 238   mp_args="-m /a,/q,/qd,/qr"
 239 fi
 240
 241 if ! $force; then
 242   if $host2_only; then
 243     if [[ $old_hostname != "$HOST2" ]]; then
 244       err "\$old_hostname($old_hostname) != \$HOST2($HOST2). Rerun with --force if you really want this."
 245       exit 1
 246     fi
 247   elif [[ $old_hostname != "$MAIL_HOST" ]]; then
 248     err "\$old_hostname($old_hostname) != \$MAIL_HOST($MAIL_HOST). Rerun with --force if you really want this."
 249     exit 1
 250   fi
 251 fi
 252
 253 if [[ ! $new_host || ! $old_host ]]; then
 254   echo "$0: bad args. see script"
 255   exit 1
 256 fi
 257
 258
 259 ########### end initial processing, begin actually modifying things ##########
 260
 261 if $new_shell systemctl is-active btrbk.timer; then
 262   m $new_shell systemctl stop btrbk.timer
 263   restore_new_btrbk=true
 264 fi
 265 if $old_shell systemctl is-active btrbk.timer; then
 266   m $old_shell systemctl stop btrbk.timer
 267   restore_old_btrbk=true
 268 fi
 269
 270 btrbk_test="systemctl is-active btrbk.service"
 271 active=true
 272 while $active; do
 273   active=false
 274   for shell in "$new_shell" "$old_shell"; do
 275     e $shell $btrbk_test
 276     status=$($shell $btrbk_test) ||:
 277     case $status in
 278       inactive|failed) : ;;
 279       *)
 280         # This covers conditions like "activating", which still return 3 from
 281         # systemctl is-active.
 282         active=true
 283         e "btrbk active on shell:$shell, status:$status, sleeping 8 seconds"
 284         sleep 8
 285         break
 286         ;;
 287     esac
 288   done
 289 done
 290
 291 # ensure these are unused before doing anything
 292 e "On $new_host: umounting /m and /o, checking emacs"
 293 {
 294   cat /usr/local/bin/unsaved-buffers
 295   if ! $host2_only; then
 296     cat <<EOF
 297 for dir in m o; do
 298   if mountpoint -q /\$dir; then
 299     echo On $new_host: umount /\$dir
 300     umount /\$dir
 301   fi
 302 done
 303 EOF
 304   fi
 305 } | $new_shell bash -s
 306
 307 if ! $mail_only; then
 308   cat /usr/local/bin/unsaved-buffers - <<'EOF' |  $old_shell bash -s
 309
 310 # Try to prevent emacs from saving stale data it has in memory to disk. eg: files, recentf list, etc.
 311 # But if emacs ignores the signal, let it live.
 312 pkill -xf 'emacs( --daemon| -f znc-all)' ||:
 313
 314 if [[ -e /p/profanity-here ]]; then
 315   systemctl disable --now profanity
 316 fi
 317 EOF
 318 fi
 319
 320 # previously, I was checking to see if the new mail host
 321 # is on my home network, then changing my home dns
 322 # to resolve on the local network, so that I didnt
 323 # have to send traffic out to the internet or rely
 324 # on that. However, that breaks for a laptop that roams.
 325 # So, we could have a cronjob that updates that dns,
 326 # however, another solution is to just use ipv6,
 327 # and I prefer that.
 328 #
 329 # TODO: enable ipv6 for email. exim config setting disables it.
 330 # need to add vpn support. need to add firewall / routing.
 331 # I think exim will try ipv6 first, so no need to disable
 332 # ipv6 i think.
 333
 334
 335 e Running initial btrbk
 336 m btrbk-run -v $bbk_args $force_arg $incremental_arg $mp_args $snapshot_arg || ret=$?
 337 if (( ret )); then
 338   err "failed initial btrbk"
 339   exit $ret
 340 fi
 341
 342 if ! $mail_only; then
 343   m $old_shell sed -ri "s/HOST2=.*/HOST2=$new_hostname/" /a/bin/bash_unpublished/source-state
 344   m $new_shell sed -ri "s/HOST2=.*/HOST2=$new_hostname/" /a/bin/bash_unpublished/source-state
 345 fi
 346
 347 if $host2_only; then
 348   if [[ $old_hostname != "$MAIL_HOST" && $old_hostname != kd ]]; then
 349     m $old_shell systemctl --now disable btrbk.timer
 350   fi
 351   m $new_shell systemctl --now enable btrbk.timer
 352   if [[ -e /p/profanity-here ]]; then
 353     m $new_shell systemctl --now enable profanity
 354   fi
 355   exit 0
 356 fi
 357
 358 m $old_shell /a/exe/primary-setup $new_hostname || ret=$?
 359 if (( ret )); then
 360   err "failed \$old_shell primary-setup \$new_hostname. fix and rerun $script_name"
 361   exit $ret
 362 fi
 363
 364
 365 e Running main btrbk
 366 m btrbk-run -v --fast $bbk_args $force_arg $incremental_arg -m /o || ret=$?
 367 if (( ret )); then
 368   bang="███████"
 369   e $bang failed btrbk of /o. restoring old host as primary
 370   if ! m $old_shell /a/exe/primary-setup localhost; then
 371     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."
 372   fi
 373   e finished restoring old host as primary, now exiting $ret due to earlier failed btrbk of /o.
 374   exit $ret
 375 fi
 376
 377 # new system is usable at this point
 378 blocks=██████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████
 379 printf "%s\n" "${blocks:0:${COLUMNS:-100}}"
 380
 381 # once I accidentally accepted incoming mail on old host. I used this script to copy over that mail:
 382 #
 383 # 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
 384
 385 # 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
 386 #
 387 # 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
 388
 389 m $new_shell /a/exe/primary-setup localhost || ret=$?
 390 if (( ret )); then
 391   err "failed final primary-setup, just fix and rerun: $new_shell /a/exe/primary-setup localhost"
 392   exit $ret
 393 fi
 394
 395 if ! $mail_only && [[ -e /p/profanity-here ]]; then
 396   m $new_shell systemctl --now enable profanity || ret=$?
 397   if (( ret )); then
 398     err "failed final systemctl --now enable profanity, just fix and rerun"
 399     exit $ret
 400   fi
 401 fi
 402
 403 m exit 0