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##*/} OLD_HOST NEW_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 -o         Only btrbk /o, instead of all filesystems.
  14 -h|--help  Print help and exit.
  15
  16 I used to adjust home network dns so NEW_HOST resolves locally if it is
  17 on the local network, but its simpler just not to and just rely
  18 on the internet. Email can wait.
  19
  20 Note: Uses GNU getopt options parsing style
  21 EOF
  22   exit $1
  23 }
  24
  25 restore_new_btrbk=false
  26 restore_old_btrbk=false
  27 cleanup() {
  28   if $restore_new_btrbk; then
  29     m $new_shell sudo systemctl start btrbk.timer
  30   fi
  31   if $restore_old_btrbk; then
  32     m $old_shell sudo systemctl start btrbk.timer
  33   fi
  34 }
  35 _errcatch_cleanup=cleanup # used by sourced err
  36
  37 pre="${0##*/}:"
  38 m() { printf "$pre %s\n"  "$*"; "$@"; }
  39 e() { printf "$pre %s\n"  "$*"; }
  40
  41 ##### begin command line parsing ########
  42
  43 temp=$(getopt -l help owh "$@") || usage 1
  44 mp_args="-m /o,/q,/a"
  45 eval set -- "$temp"
  46 while true; do
  47   case $1 in
  48     -o) mp_args="-m /o"; shift ;;
  49     -h|--help) usage ;;
  50     --) shift; break ;;
  51     *) echo "$0: Internal error! unexpected args: $*" ; exit 1 ;;
  52   esac
  53 done
  54
  55
  56 (( $# == 2 )) || usage 1
  57
  58 old_host=$1
  59 new_host=$2
  60 source /a/bin/bash_unpublished/source-state
  61
  62 if [[ $old_host != "$MAIL_HOST" ]]; then
  63   read -r -p "warning: \$old_host != \$MAIL_HOST: $old_host != $MAIL_HOST, proceed? y/N "
  64   if [[ $REPLY != [yY] ]]; then
  65     exit 1
  66   fi
  67 fi
  68
  69 if [[ $new_host == "$HOSTNAME" ]]; then
  70   localhost_new=true
  71   new_shell=
  72 else
  73   localhost_new=false
  74   new_shell="ssh $new_host"
  75 fi
  76
  77 old_shell="ssh $old_host"
  78 if [[ $old_host == "$HOSTNAME" ]]; then
  79   old_shell=
  80 fi
  81
  82 if [[ ! $new_host || ! $old_host ]]; then
  83   echo "$0: bad args. see script"
  84   exit 1
  85 fi
  86
  87 e $new_shell hostname
  88 new_hostname=$($new_shell hostname)
  89
  90 ########### end initial processing, begin actually modifying things ##########
  91
  92 if $new_shell systemctl is-active btrbk.timer; then
  93   m $new_shell sudo systemctl stop btrbk.timer
  94   restore_new_btrbk=true
  95 fi
  96 if $old_shell systemctl is-active btrbk.timer; then
  97   m $old_shell sudo systemctl stop btrbk.timer
  98   restore_old_btrbk=true
  99 fi
 100
 101 btrbk_test="systemctl is-active btrbk.service"
 102 while true; do
 103   for shell in "$new_shell" "$old_shell"; do
 104     e $shell $btrbk_test
 105     status=$($shell $btrbk_test) ||:
 106     case $status in
 107       inactive|failed) : ;;
 108       *)
 109         e "btrbk active on shell:$shell, status:$status, sleeping 8 seconds"
 110         sleep 8
 111         continue
 112         ;;
 113     esac
 114   done
 115   break
 116 done
 117
 118 # ensure these are unused before doing anything
 119
 120 e "umounting /m and /o via $new_shell"
 121 $new_shell bash -xs <<'EOF'
 122 set -eE
 123 if mountpoint -q /m; then sudo umount /m; fi
 124 if mountpoint -q /o; then sudo umount /o; fi
 125 EOF
 126
 127 # previously, I was checking to see if the new mail host
 128 # is on my home network, then changing my home dns
 129 # to resolve on the local network, so that I didnt
 130 # have to send traffic out to the internet or rely
 131 # on that. However, that breaks for a laptop that roams.
 132 # So, we could have a cronjob that updates that dns,
 133 # however, another solution is to just use ipv6,
 134 # and I prefer that.
 135 #
 136 # TODO: enable ipv6 for email. exim config setting disables it.
 137 # need to add vpn support. need to add firewall / routing.
 138 # I think exim will try ipv6 first, so no need to disable
 139 # ipv6 i think.
 140
 141 m $old_shell /a/exe/primary-setup $new_hostname
 142
 143 if $localhost_new; then
 144   m btrbk-run -v -s $old_host $mp_args
 145 else
 146   m btrbk-run -v -t $new_host $mp_args
 147 fi
 148
 149 m $new_shell /a/exe/primary-setup $new_hostname