CODEWITHSUNDEEP
javaperlservletssh
abierto
abierto

Reputation: 1467

Call Unix Shell commands from Servlet/JSP

I need to call some Unix commands from my Servlet. I have some Perl script, but I want to "translate" them into Java. Here is something that I want to do on Java, but that I've made in Perl:

system("myfolder/myscript.sh > /myfolder/logs/myscript.log");

Is it possible to do this on a Servlet?

Upvotes: 2

Views: 5572

Answers (3)

TheZuck
TheZuck

Reputation: 3621

Short answer:

it's possible but it's bad design, and can pose a security risk. better to flag somehow that the script needs to run and check the flag via script

Long answer (following the commments):

Servlets are usually used to provide a user interface (or api) to something, for example accessing data or in your case triggering an action. As such, they imply the possibility of access from a remote resource such as a remote computer. In some (actually most) cases, that remote computer may even be out of the network, for example somebody's home.

Every server which is exposed to the outside world has the potential of being hacked or attacked in some way, with the risk being directly related to the level of interest this resource poses.

For example, if you work for a big company (which is then noticeable by hackers), and this servlet is used to trigger a build in your local repository, and you decide that developers will be able to work from home and need to login in order to trigger a build or check their build status, it means that anyone with the right credentials can potentially access the servlet, from anywhere in the world. Now lets assume that your perl script needs to access your CI server for some data, and your source repository for another data (maybe it even copies the sources instead of letting the CI server do it). In this case, you just created a direct link between someone sitting somewhere in the world, to the company's source code. It also means that even if it's too hard to penetrate your incredibly secure service because you spent a vast amount of time closing all potential gaps, they may still be able to trigger many unnecessary builds, and if you work in Continuous Deployment even make those builds go to production (maybe causing a DOS attack or service disruption). If at some point someone decides that the script also needs to get a parameter from the servlet, you've even made the hacker's life easier and could eventually give him access to your system.

All I described in the previous paragraph may be completely irrelevant to your case, you might be developing a service which will run on your home computer and won't interest anyone but yourself, but this does not change the fact that this is bad design (which might be ok for home use by the way).

What I said in the short answer is that it's better to have servlets flag the system that an action is needed, for example set a flag in DB or even in a file, in this case a hacker's life would be much more difficult, as there's no direct link. This also makes the servlet respond immediately, possibly automatically updating on status, instead of waiting for the perl script to finish running.

Upvotes: 2

Reimeus
Reimeus

Reputation: 159754

Yes, but note that redirect is part of the shell you will want:

ProcessBuilder pb = 
   new ProcessBuilder("/bin/sh", "-c", "myfolder/myscript.sh > /myfolder/logs/myscript.log");
pb.start();

Upvotes: 4

Akhilesh
Akhilesh

Reputation: 1410

Did u try Jsch.It can do ssh and execute shell commands.

Upvotes: 0

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