system() with 2 commands

Base question
--------
Is there a way to perform 2 commands via system()?  I would like to
execute a "sudo - root" and then "useradd" (or perhaps a script that
does the "useradd")?

Details
-------
I am relatively new to perl, and I am writing a cgi-script that will be
a front end for adding a user -- it takes input from a form (username,
UID, group, password) and performs in a loop across other servers:

system("ssh", "-l", $user, "-q", $SERVER{$loop}, $addcommand, "| 2>&1
>/dev/null");

I was able to get this working, but the $addcommand is a simple "cat of
a file into a temp file" to confirm it works.  I need to perform a
"useradd" with all the options as the root user.  The script is run as
a different user, so I will need to su to root (add su - root in
sudoers), and then perform the "useradd" command passing all the
arguements.

sitnam81 <michael.n.palassis@gmail.com> wrote:
> Base question
> --------
> Is there a way to perform 2 commands via system()?  I would like to
> execute a "sudo - root" and then "useradd" (or perhaps a script that
> does the "useradd")?

I think you may be confusing 'su' and 'sudo'. With the latter, the
command to be executed is provided at the same time:

sudo -u root useradd

Where you will run into problems is when the stage when you asked for
the root password.

You should look at the Expect.pm module.

Axel

sitnam81 wrote:

> Base question
> --------
> Is there a way to perform 2 commands via system()?  I would like to
> execute a "sudo - root" and then "useradd" (or perhaps a script that
> does the "useradd")?
>
> Details
> -------
> I am relatively new to perl, and I am writing a cgi-script that will be
> a front end for adding a user -- it takes input from a form (username,
> UID, group, password) and performs in a loop across other servers:
>
> system("ssh", "-l", $user, "-q", $SERVER{$loop}, $addcommand, "| 2>&1 
>
> I was able to get this working, but the $addcommand is a simple "cat of
> a file into a temp file" to confirm it works.  I need to perform a
> "useradd" with all the options as the root user.  The script is run as
> a different user, so I will need to su to root (add su - root in
> sudoers), and then perform the "useradd" command passing all the
> arguements.


system('command1;command2');

System just passes its arguments to your default shell. You can then use the
usual shell programming constructs.

You many have to be a bit careful if you are doing redirections like your
example, but no more so than if you are doing shell programming.

gtoomey

Does that command work -- "sudo -u root"?
The man for root says -u is for any user OTHER than root:
-u  The -u (user) option causes sudo to run the specified
command as a user other than root.  To specify a uid
instead of a username, use "#uid".
Thanks for the recommendation about expect, this looks like it will
help with the passwd stuff.

Also the script is giving me errors when i use the ";" between
commands:

$command = "sudo /usr/bin/su - root";
$command2 = "mv $file1 $file2";
$sshserver = servername;
$user = username;
system("ssh", "-l", $user, "-q", $sshserver, $command;$command2);

# ./rsh-test.cgi
syntax error at ./rsh-test.cgi line 24, near "$command;"
syntax error at ./rsh-test.cgi line 24, near "$command2)"
Execution of ./rsh-test.cgi aborted due to compilation errors.

Do you know why this is erroring?

Thanks!

sitnam81 wrote:
> Also the script is giving me errors when i use the ";" between
> commands:
>
> $command = "sudo /usr/bin/su - root";
> $command2 = "mv $file1 $file2";
> $sshserver = servername;
> $user = username;
> system("ssh", "-l", $user, "-q", $sshserver, $command;$command2);
>
> # ./rsh-test.cgi
> syntax error at ./rsh-test.cgi line 24, near "$command;"
> syntax error at ./rsh-test.cgi line 24, near "$command2)"
> Execution of ./rsh-test.cgi aborted due to compilation errors.
>
> Do you know why this is erroring?

Post real code!

Ahhh.. it's a syntax error on line 24...  Look on line 24. :-)

system('ssh', '-l', $user, '-q', $sshserver, "$command;$command2");

A simpler & slightly less secure approach would be to set up root's ssh
keys (authorized_keys) to let you connect to $sshserver as root.  That
way you don't have to run the sudo.  If you're going to stick to using
sudo, simply run "sudo mv $file1 $file2", the "su -" will put you into
~root.

Based on the above code, I'd strongly suggest that you read up on sudo
and su before doing or allowing things to be done as root. If I saw
someone trying to do the above on a machine of mine, I'd quickly remove
them from sudoers.

sitnam81 <michael.n.palassis@gmail.com> wrote:

> $sshserver = servername;


You should always enable warnings when developing Perl code!

You should put quotes around strings.


> system("ssh", "-l", $user, "-q", $sshserver, $command;$command2);
>
> # ./rsh-test.cgi
> syntax error at ./rsh-test.cgi line 24, near "$command;"
> syntax error at ./rsh-test.cgi line 24, near "$command2)"
> Execution of ./rsh-test.cgi aborted due to compilation errors.
>
> Do you know why this is erroring?


Yes, it is because you are not putting quotes around your strings.


--
Tad McClellan                          SGML consulting
tadmc@augustmail.com                   Perl programming
Fort Worth, Texas

In article <1114177533.708450.220440@g14g2000cwa.googlegroups.com>, sitnam81
wrote:
> Does that command work -- "sudo -u root"?
> The man for root says -u is for any user OTHER than root:
>      -u  The -u (user) option causes sudo to run the specified
>          command as a user other than root.  To specify a uid
>          instead of a username, use "#uid".
> Thanks for the recommendation about expect, this looks like it will
> help with the passwd stuff.

It should work just fine. Typically, '-u root' is redundant because the defa
ult
user to run as *is* root...

Kevin


--
Unix Guy Consulting, LLC
Unix and Linux Automation, Shell, Perl and CGI scripting
http://www.unix-guy.com

sitnam81 <michael.n.palassis@gmail.com> wrote:
> Does that command work -- "sudo -u root"?
> The man for root says -u is for any user OTHER than root:
>     -u  The -u (user) option causes sudo to run the specified
>         command as a user other than root.  To specify a uid
>         instead of a username, use "#uid".

It works (at least on MAC OS X) - but you are right, 'sudo' on its
own is sufficient.

Axel

I would love to do this as a non-root user, but I have been
unsuccessful in the future in allow another user to execute a command
(in this case useradd) with variable parameters.  Also, I do have ssh
keys setup, but for a non root user -- therefore, I when I ssh into a
server I am not root, but I need to perform a useradd...

Is there a way I could do the following in sudoers (passing the
username/UID/group):

Cmnd_Alias USERADD=useradd -d /export/home/$1 -u $2 -g $3 -s /bin/bash
-m $1

Since I have been unsuccessfule setting up stuff in sudoers with
variable parameters, I figured that I was forced to ssh as a non-root
user, swith to root, and then perform the useradd with the parameters
input from the front-end form.