1 ## Remoteusage without password-free login requirement
3 This is alternative to [[remoteusage|remoteusage]] where password-free
4 login is not a requirement. See [[remoteusage|remoteusage]] page for
5 other requirements and general information.
7 This solution uses one pre-made ssh connection where the client is put
8 into "master" mode (-M) for connection sharing. The wrapper script then
9 uses the control socket created by this pre-made ssh connection for
10 its own connection. As long as master ssh connection is live, slave
11 can use it. Disconnecting master all future attempts to connect
12 from the script will fail.
16 Write the following code to a file, for example `remote-notmuch.sh`.
20 # http://notmuchmail.org/remoteusage/aboriginal/
23 #exec 2>>remote-errors; echo -- >&2; set -x # outcomment for debugging
25 readonly SSH_CONTROL_SOCK='~'/.ssh/master-user@host:22
27 readonly notmuch=notmuch
29 printf -v ARGS '%q ' "$@" # bash feature
31 readonly SSH_CONTROL_ARGS='-oControlMaster=no -S '$SSH_CONTROL_SOCK
33 if ssh -q $SSH_CONTROL_ARGS 0.1 $notmuch $ARGS
38 # continuing here in case ssh exited with nonzero value.
41 'config get user.primary_email') echo 'nobody@nowhere.invalid'; exit 0 ;;
42 'config get user.name') echo 'nobody'; exit 0 ;;
43 'count'*'--batch'*) while read line; do echo 1; done; exit 0 ;;
44 'count'*) echo 1; exit 0 ;;
45 'search-tags'*) echo 'errors'; exit 0 ;;
46 'search'*'--output=tags'*) echo 'errors'; exit 0 ;;
49 if ssh $SSH_CONTROL_ARGS -O check 0.1
51 echo ' Control socket is alive but something failed during data transmission.'
55 echo " See`sed '1d;2d;s/.//;q' "$0"` for help."
57 Note the `0.1` in ssh command line. It is used to avoid any opportunistic
58 behaviour ssh might do; for example if control socket is not alive ssh
59 would attempt to do it's own ssh connection to remote ssh server. As
60 address `0.1` is invalid this attempt will fail early.
64 Easiest way to test this script is to run the pre-made ssh connection
65 using the following command line:
67 ssh -M -S '~'/.ssh/master-user@host:22 [user@]remotehost
69 (replace `[user@]remotehost` with your login info). Doing this the
70 above script can be run unmodified. After the above command has been
71 run on one terminal, enter `chmod +x remote-notmuch.sh` in another
72 terminal and then test the script with `./remote-notmuch.sh help`
74 Note that the '~' is inside single quotes for a reason. In this
75 case shell never expand it to `$HOME` -- ssh does it by not reading
76 `$HOME` but checking the real user home directory from `/etc/passwd`.
77 For security purposes this is just how it should be.
81 The path `'~'/.ssh/master-user@host:22` might look too generic to be
82 used as is as the control socket after initial testing (but it can
83 be used). It is presented as a template for what could be configured
84 to `$HOME/.ssh/config`. For example:
87 ControlPath ~/.ssh/master-%h@%p:%r
89 is a good entry to be written in `$HOME/.ssh/config`;
90 [[remoteusage|remoteusage]] uses the same. Now, let's say you'd
91 make your pre-made ssh connection with command
93 ssh -M alice@example.org
96 `readonly SSH_CONTROL_SOCK='~'/.ssh/master-alice@example.org:22`
97 to the `./remote-notmuch.sh` wrapper script testing with
98 `./remote-notmuch.sh help` should work fine.
100 ## Configure Emacs on the client computer ##
102 See the section *Configure Emacs on the client computer* in
103 [[remoteusage|remoteusage]] how to do this. The instructions are the same.