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: ${0##*/} [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 -i         Disallow incremental backup.
  14 -o         Only btrbk /o, instead of all filesystems.
  15 -h|--help  Print help and exit.
  16
  17 I used to adjust home network dns so NEW_HOST resolves locally if it is
  18 on the local network, but its simpler just not to and just rely
  19 on the internet. Email can wait.
  20
  21 Note: Uses GNU getopt options parsing style
  22 EOF
  23   exit $1
  24 }
  25
  26
  27 restore_new_btrbk=false
  28 restore_old_btrbk=false
  29 err-cleanup() {
  30   if $restore_new_btrbk; then
  31     e WARNING: due to failure, btrbk.timer may need manual restoration:
  32     e $new_shell systemctl start btrbk.timer
  33   fi
  34   if $restore_old_btrbk; then
  35     e WARNING: due to failure, btrbk.timer may need manual restoration:
  36     e $old_shell systemctl start btrbk.timer
  37   fi
  38 }
  39
  40 pre="${0##*/}:"
  41 m() { printf "$pre %s\n"  "$*"; "$@"; }
  42 e() { printf "$pre %s\n"  "$*"; }
  43 err() { echo "$pre ERROR: $*" >&2; }
  44
  45 if [[ $EUID != 0 ]]; then
  46   err "requires running as root"
  47   exit 1
  48 fi
  49
  50
  51 ##### begin command line parsing ########
  52
  53 force=false
  54 mp_args="-m /o,/q,/a"
  55 temp=$(getopt -l force,help ioh "$@") || usage 1
  56 eval set -- "$temp"
  57 while true; do
  58   case $1 in
  59     --force) force=true ;;
  60     -i) incremental_arg="-i" ;;
  61     -o) mp_args="-m /o" ;;
  62     -h|--help) usage ;;
  63     --) shift; break ;;
  64     *) echo "$0: Internal error! unexpected args: $*" ; exit 1 ;;
  65   esac
  66   shift
  67 done
  68
  69
  70 (( $# == 2 )) || usage 1
  71
  72 if [[ ! $HOSTNAME ]]; then
  73   err "\$HOSTNAME is unset"
  74   exit 1
  75 fi
  76
  77 case $1 in
  78   push)
  79     old_host=$HOSTNAME
  80     old_hostname=$HOSTNAME
  81     new_host=$2
  82     bbk_args="-t $new_host"
  83     new_shell="ssh -F $HOME/.ssh/confighome root@$new_host"
  84     $new_shell -v hostname
  85     new_hostname=$($new_shell hostname)
  86     ;;
  87   pull)
  88     old_host=$2
  89     new_host=$HOSTNAME
  90     new_hostname=$HOSTNAME
  91     bbk_args="-s $old_host"
  92     old_shell="ssh -F $HOME/.ssh/confighome root@$old_host"
  93     # tests ssh connection
  94     if ! old_hostname=$($old_shell hostname); then
  95       echo "retrying failed $old_shell with -v"
  96       $old_shell -v hostname
  97       exit 1
  98     fi
  99     ;;
 100   *)
 101     err invalid first argument
 102     exit 1
 103     ;;
 104 esac
 105
 106 source /a/bin/bash_unpublished/source-state
 107
 108 if [[ $old_hostname != "$MAIL_HOST" ]] && ! $force; then
 109   err "\$old_hostname($old_hostname) != \$MAIL_HOST($MAIL_HOST). Rerun with --force if you really want this."
 110   exit 1
 111 fi
 112
 113 if [[ ! $new_host || ! $old_host ]]; then
 114   echo "$0: bad args. see script"
 115   exit 1
 116 fi
 117
 118
 119 ########### end initial processing, begin actually modifying things ##########
 120
 121 if $new_shell systemctl is-active btrbk.timer; then
 122   m $new_shell systemctl stop btrbk.timer
 123   restore_new_btrbk=true
 124 fi
 125 if $old_shell systemctl is-active btrbk.timer; then
 126   m $old_shell systemctl stop btrbk.timer
 127   restore_old_btrbk=true
 128 fi
 129
 130 btrbk_test="systemctl is-active btrbk.service"
 131 active=true
 132 while $active; do
 133   active=false
 134   for shell in "$new_shell" "$old_shell"; do
 135     e $shell $btrbk_test
 136     status=$($shell $btrbk_test) ||:
 137     case $status in
 138       inactive|failed) : ;;
 139       *)
 140         # This covers conditions like "activating", which still return 3 from
 141         # systemctl is-active.
 142         active=true
 143         e "btrbk active on shell:$shell, status:$status, sleeping 8 seconds"
 144         sleep 8
 145         break
 146         ;;
 147     esac
 148   done
 149 done
 150
 151 # ensure these are unused before doing anything
 152
 153 e "On $new_host: umounting /m and /o, checking emacs"
 154 $new_shell bash -s <<'EOF'
 155 set -eE
 156 if pgrep -f 'emacs --daemon' &>/dev/null; then
 157   bufs="$(emacsclient --eval "$(cat /a/bin/ds/unsaved-buffers.el)"| sed '/^"nil"$/d;s/^"(/E: /;s/)"$//')"
 158   if [[ $bufs ]]; then
 159     echo "error: on $HOSTNAME, unsaved emacs files: $bufs" >&2
 160     exit 1
 161   fi
 162 fi
 163 for dir in m o; do
 164   if mountpoint -q /$dir; then
 165     echo On $new_host: umount /$dir
 166     umount /$dir
 167   fi
 168 done
 169 EOF
 170
 171 $old_shell bash -s <<'EOF'
 172 if pgrep -f 'emacs --daemon' &>/dev/null; then
 173   bufs="$(emacsclient --eval "$(cat /a/bin/ds/unsaved-buffers.el)"| sed '/^"nil"$/d;s/^"(/E: /;s/)"$//')"
 174   if [[ $bufs ]]; then
 175     echo "error: on $HOSTNAME, unsaved emacs files: $bufs" >&2
 176     exit 1
 177   fi
 178 fi
 179 EOF
 180
 181 # previously, I was checking to see if the new mail host
 182 # is on my home network, then changing my home dns
 183 # to resolve on the local network, so that I didnt
 184 # have to send traffic out to the internet or rely
 185 # on that. However, that breaks for a laptop that roams.
 186 # So, we could have a cronjob that updates that dns,
 187 # however, another solution is to just use ipv6,
 188 # and I prefer that.
 189 #
 190 # TODO: enable ipv6 for email. exim config setting disables it.
 191 # need to add vpn support. need to add firewall / routing.
 192 # I think exim will try ipv6 first, so no need to disable
 193 # ipv6 i think.
 194
 195
 196 e Running initial btrbk
 197 if ! m btrbk-run -v $bbk_args $incremental_arg $mp_args; then
 198   ret=$?
 199   err "failed initial btrbk"
 200   exit $ret
 201 fi
 202
 203 if ! m $old_shell /a/exe/primary-setup $new_hostname; then
 204   ret=$?
 205   err "failed \$old_shell primary-setup \$new_hostname. fix and rerun switch-mail-host"
 206   exit $ret
 207 fi
 208
 209 # Try to prevent emacs from saving stale data it has in memory to disk. eg: files, recentf list, etc.
 210 # But if emacs ignores the signal, let it live.
 211 m $new_shell killall -q emacs ||:
 212
 213 e Running main btrbk
 214 m btrbk-run -v $bbk_args $incremental_arg -m /o || ret=$?
 215 if (( ret )); then
 216   bang="$(printf "$(tput setaf 5)█$(tput sgr0)%.0s" 1 2 3 4 5 6 7)"
 217   e $bang failed btrbk of /o. restoring old host as primary
 218   m $old_shell /a/exe/primary-setup localhost
 219   exit $ret
 220 fi
 221
 222 # once I accidentally accepted incoming mail on old host. I used this script to copy over that mail:
 223 #
 224 # 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
 225
 226 # 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
 227 #
 228 # 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
 229
 230 if ! m $new_shell /a/exe/primary-setup localhost; then
 231   ret=$?
 232   err "failed final primary-setup, just fix and rerun: $new_shell /a/exe/primary-setup localhost"
 233   exit $ret
 234 fi
 235
 236 m exit 0