Connecting to SSH via PHP's exec() function.

Question

I am currently trying to figure out how to connect to another server via SSH using PHP's shell functions. I have a site where I have to pass data from PHP to a custom command line program, then return the output. On the old server I was using, this was possible via the exec() function:

$cmd = '/path/to/custom/program "arg1", "arg2", "arg3"';
exec($cms, $output);

$output, of course, would then hold the data that my program returned.

I am now in a position where the host will not allow me to run my custom program. PHP's shell functions, however, are still available. The host suggested I set up PHP to SSH into a different server, run the commands I need to run, and then return the output. This seems like an incredibly backwards way of doing things, but what do I know?

My specific question relates to how I would go about passing the login information to the exec() command. For example, when I connect to any SSH server manually, I put in:

ssh myserver.com -l myusername

And then I see:

[email protected]'s password:

If I were to pass "ssh myserver.com -l myusername" as the command to exec(), how would I then give it the password? After that, how would I then know that I am properly authenticated and connected so I can run the command for my program?

Oh, and also, I do not have access to the ssh2 functions in PHP, nor would I be able to install that extension.

Answer 1

you could use keys to get around the password problem.

http://pkeck.myweb.uga.edu/ssh/

Answer 2

You need bi-directional communication with the new process from your PHP code - that being the case, proc_open(...) is the only php function you can use to run ssh.

After that - its simply a matter of writing code to wait for prompts and respond to them.

However there is ssh implementation written in PHP posted at phpclasses - although I've no idea how fast/efficient/reliable/compatible it is. I suspect that it won't be any less effort than the proc_open() approach and possible a lot more.

C.

Answer 3

Never tried, but did you consider the PHP core functions passthru() or system().

They are similar to exec().