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

   1 #!/bin/bash
   2
   3 source /usr/local/lib/err
   4
   5 usage() {
   6   cat <<EOF
   7 Usage: switch-mail-host|switch-host2 [OPTIONS] push|pull HOST
   8
   9 Turn off mail receiving on OLD_HOST, run btrbk to move mail to NEW_HOST,
  10 turn on mail receiving on NEW_HOST.  Assumes we want to move all
  11 filesystems unless passing -o.
  12
  13 -a         Avoid snapshot /a, /q, and similar. If we haven't
  14            made any changes in the last hour, there is no
  15            need to snapshot anything but /o, and we will
  16            just do that once.
  17 -i         Disallow incremental backup.
  18 -o         Only btrbk /o, instead of all filesystems.
  19 --force    Run even though our local state does not say that MAIL_HOST is
  20            us when pushing or HOST when pulling.
  21 -h|--help  Print help and exit.
  22
  23 I used to adjust home network dns so NEW_HOST resolves locally if it is
  24 on the local network, but its simpler just not to and just rely
  25 on the internet. Email can wait.
  26
  27 Note: Uses GNU getopt options parsing style
  28 EOF
  29   exit $1
  30 }
  31
  32 script_name="${BASH_SOURCE[0]}"
  33 script_name="${script_name##*/}"
  34
  35 restore_new_btrbk=false
  36 restore_old_btrbk=false
  37 err-cleanup() {
  38   if $restore_new_btrbk; then
  39     e WARNING: due to failure, btrbk.timer may need manual restoration:
  40     e $new_shell systemctl start btrbk.timer
  41   fi
  42   if $restore_old_btrbk; then
  43     e WARNING: due to failure, btrbk.timer may need manual restoration:
  44     e $old_shell systemctl start btrbk.timer
  45   fi
  46 }
  47
  48 pre="${SSH_CLIENT:+$HOSTNAME} $script_name:"
  49 m() { printf "$pre %s\n"  "$*"; "$@"; }
  50 e() { printf "$pre %s\n"  "$*"; }
  51 err() { echo "$pre ERROR: $*" >&2; }
  52
  53 if [[ $EUID != 0 ]]; then
  54   err "requires running as root"
  55   exit 1
  56 fi
  57
  58
  59 ##### begin command line parsing ########
  60
  61 mail_only=false
  62 host2_only=false
  63 force=false
  64 mp_args="-m /o,/a,/ar,/q,/qr"
  65 temp=$(getopt -l force,help aioh "$@") || usage 1
  66 eval set -- "$temp"
  67 while true; do
  68   case $1 in
  69     -a) snapshot_arg=resume ;;
  70     --force) force=true ;;
  71     -i) incremental_arg="-i" ;;
  72     -o)
  73       mail_only=true ;;
  74     -h|--help) usage ;;
  75     --) shift; break ;;
  76     *) echo "$0: Internal error! unexpected args: $*" ; exit 1 ;;
  77   esac
  78   shift
  79 done
  80
  81
  82 (( $# == 2 )) || usage 1
  83
  84 if [[ ! $HOSTNAME ]]; then
  85   err "\$HOSTNAME is unset"
  86   exit 1
  87 fi
  88
  89 source /a/bin/bash_unpublished/source-state
  90
  91 direction=$1
  92 host=$2
  93 case $direction in
  94   push)
  95     old_host=$HOSTNAME
  96     old_hostname=$HOSTNAME
  97     new_host=$host
  98     bbk_args="-t $new_host"
  99     new_shell="ssh -F $HOME/.ssh/confighome root@$new_host"
 100     if ! new_hostname=$($new_shell hostname); then
 101       echo "$pre: error: failed ssh. retrying failed $new_shell with -v for more info:"
 102       $new_shell -v hostname
 103     fi
 104     ;;
 105   pull)
 106     old_host=$host
 107     new_host=$HOSTNAME
 108     new_hostname=$HOSTNAME
 109     bbk_args="-s $old_host"
 110     old_shell="ssh -F $HOME/.ssh/confighome root@$old_host"
 111     old_shelliank="ssh -F $HOME/.ssh/confighome iank@$old_host"
 112     # tests ssh connection. crafted this to not need to do escape chars
 113     f=/a/bin/bash_unpublished/source-state
 114     if ! old_info=($($old_shell "hostname; sed -n s,.*MAIL_HOST=,,p $f; sed -n s,.*HOST2=,,p $f")); then
 115       echo "$pre: error: failed ssh. retrying failed $old_shell with -v for more info:"
 116       $old_shell -v hostname
 117       exit 1
 118     fi
 119     old_hostname=${old_info[0]}
 120     MAIL_HOST=${old_info[1]}
 121     HOST2=${old_info[2]}
 122     ;;
 123   *)
 124     err invalid first argument
 125     exit 1
 126     ;;
 127 esac
 128
 129 case $script_name in
 130   switch-mail-host)
 131     if [[ $MAIL_HOST != "$HOST2" ]]; then
 132       mail_only=true
 133     fi
 134     ;;
 135   switch-host2)
 136     host2_only=true
 137     ;;
 138   *)
 139     err unexpected script name
 140     ;;
 141 esac
 142
 143 if $mail_only; then
 144   mp_args="-m /o"
 145 elif $host2_only; then
 146   mp_args="-m /a,/ar,/q,/qr"
 147 fi
 148
 149
 150 if $host2_only; then
 151   if [[ $old_hostname != "$HOST2" ]]; then
 152     err "\$old_hostname($old_hostname) != \$HOST2($HOST2). Rerun with --force if you really want this."
 153     exit 1
 154   fi
 155 elif [[ $old_hostname != "$MAIL_HOST" ]] && ! $force; then
 156   err "\$old_hostname($old_hostname) != \$MAIL_HOST($MAIL_HOST). Rerun with --force if you really want this."
 157   exit 1
 158 fi
 159
 160 if [[ ! $new_host || ! $old_host ]]; then
 161   echo "$0: bad args. see script"
 162   exit 1
 163 fi
 164
 165
 166 ########### end initial processing, begin actually modifying things ##########
 167
 168 if $new_shell systemctl is-active btrbk.timer; then
 169   m $new_shell systemctl stop btrbk.timer
 170   restore_new_btrbk=true
 171 fi
 172 if $old_shell systemctl is-active btrbk.timer; then
 173   m $old_shell systemctl stop btrbk.timer
 174   restore_old_btrbk=true
 175 fi
 176
 177 btrbk_test="systemctl is-active btrbk.service"
 178 active=true
 179 while $active; do
 180   active=false
 181   for shell in "$new_shell" "$old_shell"; do
 182     e $shell $btrbk_test
 183     status=$($shell $btrbk_test) ||:
 184     case $status in
 185       inactive|failed) : ;;
 186       *)
 187         # This covers conditions like "activating", which still return 3 from
 188         # systemctl is-active.
 189         active=true
 190         e "btrbk active on shell:$shell, status:$status, sleeping 8 seconds"
 191         sleep 8
 192         break
 193         ;;
 194     esac
 195   done
 196 done
 197
 198 # ensure these are unused before doing anything
 199 e "On $new_host: umounting /m and /o, checking emacs"
 200 {
 201   cat <<'EOF'
 202 set -eE
 203 if pgrep -G iank -u iank -f 'emacs --daemon' &>/dev/null; then
 204   bufs="$(sudo -u iank env XDG_RUNTIME_DIR=/run/user/1000 emacsclient --eval "$(cat /a/bin/ds/unsaved-buffers.el)"| sed '/^"nil"$/d;s/^"(/E: /;s/)"$//')"
 205   if [[ $bufs ]]; then
 206     echo "error: on $HOSTNAME, unsaved emacs files: $bufs" >&2
 207     exit 1
 208   fi
 209 fi
 210 EOF
 211   if ! $host2_only; then
 212     cat <<EOF
 213 for dir in m o; do
 214   if mountpoint -q /\$dir; then
 215     echo On $new_host: umount /\$dir
 216     umount /\$dir
 217   fi
 218 done
 219 EOF
 220   fi
 221 } | $new_shell bash -s
 222
 223 $old_shell bash -s <<'EOF'
 224 if pgrep -G iank -u iank -f 'emacs --daemon' &>/dev/null; then
 225   bufs="$(sudo -u iank env XDG_RUNTIME_DIR=/run/user/1000 emacsclient --eval "$(cat /a/bin/ds/unsaved-buffers.el)"| sed '/^"nil"$/d;s/^"(/E: /;s/)"$//')"
 226   if [[ $bufs ]]; then
 227     echo "error: on $HOSTNAME, unsaved emacs files: $bufs" >&2
 228     exit 1
 229   fi
 230 fi
 231 EOF
 232
 233 # previously, I was checking to see if the new mail host
 234 # is on my home network, then changing my home dns
 235 # to resolve on the local network, so that I didnt
 236 # have to send traffic out to the internet or rely
 237 # on that. However, that breaks for a laptop that roams.
 238 # So, we could have a cronjob that updates that dns,
 239 # however, another solution is to just use ipv6,
 240 # and I prefer that.
 241 #
 242 # TODO: enable ipv6 for email. exim config setting disables it.
 243 # need to add vpn support. need to add firewall / routing.
 244 # I think exim will try ipv6 first, so no need to disable
 245 # ipv6 i think.
 246
 247
 248 e Running initial btrbk
 249 m btrbk-run -v $bbk_args $incremental_arg $mp_args $snapshot_arg || ret=$?
 250 if (( ret )); then
 251   err "failed initial btrbk"
 252   exit $ret
 253 fi
 254
 255 if ! $mail_only; then
 256   m $old_shell sed -ri "s/HOST2=.*/HOST2=$new_hostname/" /a/bin/bash_unpublished/source-state
 257   m $new_shell sed -ri "s/HOST2=.*/HOST2=$new_hostname/" /a/bin/bash_unpublished/source-state
 258 fi
 259
 260 if $host2_only; then
 261   if [[ $old_hostname != "$MAIL_HOST" && $old_hostname != kd ]]; then
 262     m $old_shell systemctl --now disable btrbk.timer
 263   fi
 264   m $new_shell systemctl --now enable btrbk.timer
 265   exit 0
 266 fi
 267
 268 m $old_shell /a/exe/primary-setup $new_hostname || ret=$?
 269 if (( ret )); then
 270   err "failed \$old_shell primary-setup \$new_hostname. fix and rerun $script_name"
 271   exit $ret
 272 fi
 273
 274 # Try to prevent emacs from saving stale data it has in memory to disk. eg: files, recentf list, etc.
 275 # But if emacs ignores the signal, let it live.
 276 m $new_shell killall -q emacs ||:
 277
 278 e Running main btrbk
 279 m btrbk-run -v --fast $bbk_args $incremental_arg -m /o || ret=$?
 280 if (( ret )); then
 281   bang="$(printf "$(tput setaf 5)█$(tput sgr0)%.0s" 1 2 3 4 5 6 7)"
 282   e $bang failed btrbk of /o. restoring old host as primary
 283   m $old_shell /a/exe/primary-setup localhost
 284   exit $ret
 285 fi
 286
 287 # new system is usable at this point
 288 printf "$(tput setaf 5 2>/dev/null ||:)█$(tput sgr0 2>/dev/null||:)%.0s" $(eval echo "{1..${COLUMNS:-60}}")
 289 echo
 290
 291 # once I accidentally accepted incoming mail on old host. I used this script to copy over that mail:
 292 #
 293 # 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
 294
 295 # 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
 296 #
 297 # 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
 298
 299 m $new_shell /a/exe/primary-setup localhost || ret=$?
 300 if (( ret )); then
 301   err "failed final primary-setup, just fix and rerun: $new_shell /a/exe/primary-setup localhost"
 302   exit $ret
 303 fi
 304
 305 m exit 0