Execute multiple CLI commands via ssh2_exec in the same shell

Question

I've been trying to execute two or more commands on a remote device by using PHP's ssh2_exec command but it doesn't seem to be able to execute a command, wait for a response and execute another one.

The second command that I need to run must be in the context of the first command so it must be executed in the same shell. What I mean is something like this

FWEFW # config system admin

This command will take me into a "context". The result will be something like:

FWEFW (admin) #

From here, I'd like to run a second command that could set the password or another field of (admin)

FWEFW (admin) # set password 'abcde'

Here's what I've tried so far:

$stream = ssh2_exec($con, 'config system admin');
stream_set_blocking($stream, TRUE);
$output = ssh2_fetch_stream($stream, SSH2_STREAM_STDIO);

// After this, what can I do to stay in the same shell and execute the second command after "config system admin"?

Gloire · Accepted Answer · 2017-09-14 11:51:27Z

After a lot of frustration, I've come to the following conclusion:

The ssh2_exec command is useful when you need to run a single command. In my case, I needed to run multiple commands in the same session before getting the result that I needed. In order to do so here's how I went about it:

Create an interactive shell

$shell = ssh2_shell($connection, 'xterm', NULL, 400, 400, SSH2_TERM_UNIT_CHARS)

Execute your first command

fwrite($shell, 'command 1' . PHP_EOL); // Don't forget PHP_EOL => /n

Wait for the whole stream

stream_set_blocking($shell, TRUE);

Run your second command

fwrite($shell, 'command 2' . PHP_EOL);

So on and so on. I've tested it with four commands and it worked just fine.

After you've executed all the commands you can retrieve the result by "accessing the shell"

$data = "";
$buf  = NULL;

while (! feof($shell))
{
    $buf = fread($shell, 4096);
    $data .= $buf;
}

fclose($shell);

The data you need is now stored in the $data variable. Note that, should your shell be stuck at prompt (the case most of the time) the loop will run forever until a timeout error is thrown.

To get around that, I had to run the 'exit' command in order to exit the shell.

You may also look at using the phpseclib package. The package had a serious impact on performance as the operation took close to 10 seconds and that was not acceptable.

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