CODEWITHSUNDEEP
c++linuxshell
Jeroen
Jeroen

Reputation: 16885

How to run a C++ program inside another C++ program?

I will sketch the scenario I would like to get working below.

I have one main application. That application, based on user interactions, can load other applications inside a secure environment/shell. This means these child applications cannot interact with the OS anymore, nor with each other.

The parent program can at any time call functions of these child programs. The child program can at any time call functions of these parent programs.

Does anyone know how to implement this in C++? Preferably both parent and child should be written in C++.

The performance of loading the child applications inside the parent application doesn't matter. The only thing that matters is the performance of the communication between child and parent when calling functions of each other.

Upvotes: 8

Views: 2603

Answers (4)

Mamad
Mamad

Reputation: 1

I am not familiar with OS restrictions in above answers. However, I found an easy way to solve this problem. I hope it helps and does not have a technical issue. I used Linux OS. Suppose I want to call C++ program B inside another C++ program A. I wrote a perl script (such as PerlScript.pl) that contains a system call to run program B. Then in A, I did a system call like system("perl PerlScript.pl") that ask perl to run B for me.

Upvotes: -1

MSalters
MSalters

Reputation: 180305

You will have to write your own compiler.

Consider: No normal OS supports what you want. You want both executables to run inside a single process, yet that process may or may not make OS calls depending on some weirdness inside the process which the OS doesn't understand at all.

This is no longer a problem with your custom compiler, as it simply will not create the offending instructions. It's similar to Java and .Net, which also prevent such OS calls outside their control.

Upvotes: 3

ArtemGr
ArtemGr

Reputation: 12567

A portable solution: Google Native Client

One possible Linux solution:

  1. Make AppArmor profile with "hats" (a "hat" is a sandboxing configuration to which the application can switch programmatically with libapparmor),
  2. have the main application create a "pipe",
  3. have the main application "fork",
  4. change into a "hat" corresponding to the child application,
  5. "exec" the child application,
  6. the main application and the child application communicate via the "pipe" created earlier.

Upvotes: 2

Radu Chivu
Radu Chivu

Reputation: 1075

If you want a (semi)crossplatform way to do this you can use RPC to call functions in another process. It's going to work on anything that supports the distributed computing environment. It's been around for some time and the msdn documentation states that parts of windows use it for inter process communication so it's probably fast enough. Here's a tutorial on msdn that should get you up and running http://msdn.microsoft.com/en-us/library/windows/desktop/aa379010.aspx The bad part is that I haven't been able to find a tutorial about using it on linux.

If you don't want to use RPC or find it too hard to find good documentation on the subject, you can use the standard IPC(Inter Process Communication) mechanisms from unix systems to signal your process that should call a certain function. I'd recommend a message queue because it's very fast and lightweight. You can find a tutorial here: http://www.cs.cf.ac.uk/Dave/C/node25.html

Upvotes: 0

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