is it possible to make a function execute code from a string on the stack?

Question

#include 

int main(int argc, char** argv)
{
    void (*p) (void);
    /* this obviously won\'t work, but what string could I put in 
       here (if          


        

Answer 1

You could use libtcc to compile and run C source code:

const char *code = "int main(int argc, char**argv) { printf(\"Hello, world!\"); return 0; }";
TCCState *tcc = tcc_new();

if (tcc_compile_string(tcc, code))
{
    // an error occurred compiling the string (syntax errors perhaps?)
}

int argc = 1;
char *argv[] = { "test" };

int result = tcc_run (tcc, argc, argv);

// result should be the return value of the compiled "main" function.
// be sure to delete the memory used by libtcc

tcc_delete(tcc);

A coouple of issues:

1. You can only compile libtcc on a supported architecture.
2. You need to have a main function.