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insyte is offline insyte
2009-12-07 , 18:03
Posts: 4 | Thanked: 8 times | Joined on Nov 2009
#1
As a sysadmin, one of the most common ways I use my N900 is to manage servers via ssh. Spawning an instance of ssh-agent for each xterm session (and typing in the ssh key's passphrase) quickly became painful. So I wrote a few lines of code that can be dropped into ~/.profile to make sure I can reuse a shared agent between all sessions.

Code:
unset SSH_AUTH_SOCK
unset SSH_AGENT_PID

if [[ -f ~/.ssh-agent ]]
then
        source ~/.ssh-agent >> /dev/null
fi

ssh-add -l 2>&1 > /dev/null
r=$?
if [[ $r == 2 ]]
then
        echo No agent.
        pkill ssh-agent
        ssh-agent -t 5400 > ~/.ssh-agent
        source ~/.ssh-agent > /dev/null
fi
Full write-up and explanation here:

http://insyte.squad51.net/archives/2...7T11_55_19.txt
 

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lnagel is offline lnagel
2010-03-15 , 20:15
Posts: 3 | Thanked: 4 times | Joined on Mar 2010
#2
Here's a variation of your script (thanks for the original one!

* fixed the no connection warning by changing "2>&1" to "2> /dev/null"
* moved the agent file to ~/.ssh/
* added a few aliases to manage the keys more easily (list, add, delete)

Code:
unset SSH_AUTH_SOCK
unset SSH_AGENT_PID

agentfile="/home/user/.ssh/agent"

if [[ -f ${agentfile} ]]; then
        source ${agentfile} >> /dev/null
fi

ssh-add -l 2> /dev/null > /dev/null
r=$?
if [[ $r == 2 ]]
then
        pkill ssh-agent
        ssh-agent -t 900 > ${agentfile}
        source ${agentfile}> /dev/null
        chmod 600 ${agentfile}
fi

unset agentfile

alias idlist="ssh-add -l"
alias idrsa="ssh-add /home/user/.ssh/id_rsa"
alias idrsadel="ssh-add -d /home/user/.ssh/id_rsa"
Last edited by lnagel; 2010-03-15 at 20:27.
 

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nyarlathotep is offline nyarlathotep
2010-03-15 , 21:24
Posts: 14 | Thanked: 2 times | Joined on Mar 2010
#3
I'd suggest starting the ssh-agent before X because otherwise tasks spawned outside a shell don't have access.

Mac OS X has a very nice ssh-agent setup. ssh-agent itself will be restarted by launchd (inetd) whenever needed, but the ssh-agent itself opens a secure password dialog.

p.s. You can suppress ssh-add's error message if you put the 2>&1 after the >dev/null
 

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Rob1n is offline Rob1n
2010-03-15 , 21:42
Posts: 3,617 | Thanked: 2,412 times | Joined on Nov 2009 @ Cambridge, UK
#4
Originally Posted by nyarlathotep View Post
I'd suggest starting the ssh-agent before X because otherwise tasks spawned outside a shell don't have access.
A good thought. I've added /etc/X11/Xsession.d/00ssh-agent containing:
Code:
#!/bin/sh
eval `ssh-agent -s -t 900`
That seems to do the job of starting the agent along with X, making the environment variables accessible to all launched applications.
 

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ugknite is offline ugknite
2010-07-14 , 13:27
Posts: 18 | Thanked: 2 times | Joined on Nov 2009
#5
thanks guys, this is handy.

Rob1n, what does the 00 in 00ssh-agent signify?
 
ugknite is offline ugknite
2010-07-14 , 13:41
Posts: 18 | Thanked: 2 times | Joined on Nov 2009
#6
After adding to Xsession.d/00ssh-agent the agent starts up but the environment variables aren't exported properly.
Rob1n, did you see the environment variables after starting the device?
 
stuart34 is offline stuart34
2012-11-11 , 13:18
Posts: 7 | Thanked: 10 times | Joined on Apr 2011
#7
I run the agent and have the environment variables correctly exported with a /etc/X11/Xsession.d/00ssh-agent containing

Code:
eval `ssh-agent -s -t 7d`
I didn't add #!/bin/sh because this code has to be sourced rather than executed.
 

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