Re: ssh-pageant

[Andrey Repin <anrdaemon@yandex.ru>]

Greetings, Chris Rodgers!

> I find the ssh-pageant package helpful to enable cygwin ssh to interact
> seamlessly with PuTTY's Pageant SSH agent. One small issue is that after 
> installing, one has to add the lines:

>> |# ssh-pageant eval $(/usr/bin/ssh-pageant -r -a 
>> "/tmp/.ssh-pageant-$USERNAME")|
> (see https://github.com/cuviper/ssh-pageant) 
> <https://github.com/cuviper/ssh-pageant>to .bashrc for each user.

> Would it be acceptable to update the ssh-pageant package to add a file 
> /etc/profile.d/ssh-pageant.sh that does this automatically?

It's not that simple. You can't blindly restart agent every time you wish
without notifying other programs, `--reuse` is a very bad idea and there's
no easy way to set/change an environment variable globally for an entire
user session.

> Or is there another preferred way to do this, e.g. a postinstall script?

> I'd be happy to draft a script file for review.

Just create a script for yourself and amend your own .bashrc accordingly.

I do it this way:

1. Add

----- 8< ----- 8< ----- 8< ----- 8< -----
# Import ssh-pageant settings
test -f "$HOME/.ssh/agent" && . "$HOME/.ssh/agent"
----- >8 ----- >8 ----- >8 ----- >8 -----

near the end of .bashrc

2. Create a script `$HOME/profile.d/ssh-pageant.sh`

----- 8< ----- 8< ----- 8< ----- 8< -----
#!/bin/sh

[ -x /usr/bin/ssh-pageant ] || return

_agent="$HOME/.ssh/agent"
eval set -- $( getopt --shell=sh -o 'k' -- "$@" )

test -f "$_agent" && . "$_agent"

if [ "$SSH_PAGEANT_PID" ]; then
  if test "$1" = "-k"; then
    /usr/bin/ssh-pageant -qk 2> /dev/null
  fi

  if ! kill -0 "$SSH_PAGEANT_PID" 2> /dev/null; then
    # Reap dead agent's socket
    rm "$SSH_AUTH_SOCK" "$_agent" 2> /dev/null
    unset SSH_AUTH_SOCK SSH_PAGEANT_PID
  fi
fi

test "$1" = "-k" && exit
test "$SSH_PAGEANT_PID" && exit

socket="$( mktemp -u /var/run/ssh-XXXXXXXX )"
eval $( cygdrop -- /usr/bin/ssh-pageant -qsa "$socket" | tee "$_agent" )

# Remove empty settings file (agent failed to start).
test -s "$_agent" || rm "$_agent"
----- >8 ----- >8 ----- >8 ----- >8 -----

3. Create login job to run scripts from ~/profile.d/ on user login.

4. If you need agent settings in a different script, that may be run outside
normal terminal/shell workflow, just add

----- 8< ----- 8< ----- 8< ----- 8< -----
test -f "$HOME/.ssh/agent" && . "$HOME/.ssh/agent"
----- >8 ----- >8 ----- >8 ----- >8 -----

near the top.

5. Don't forget to `ssh-pageant.sh -k` before running Cygwin setup.


-- 
With best regards,
Andrey Repin
Thursday, April 23, 2020 21:28:24

Sorry for my terrible english...