#include <iostream>

#include <sys/types.h>   //getpid, ...
#include <unistd.h>      // everyting
#include <string.h>      // for strdup
#include <libgen.h>

using namespace std;

int main(int argc, char * argv[]) {

    char ** progArgs;
    char ** progEnv;
    int i;

    // args -2 + name, generated, constant, null
    progArgs = new char * [argc+2];

    progEnv = new char * [3];

    if(argc ==1) {
      cerr << "Usage " << argv[0] << " program args ..." << endl;
    }

    // build the environment
    progEnv[0] = strdup("hello=World");
    progEnv[1] = strdup("PATH=/bin:/usr/bin:.");
    progEnv[2] = nullptr;

    // set the basename
    progArgs[0] = basename(argv[1]);

    // copy over the passed in args
    for(i = 2;i<argc;i++) {
       progArgs[i-1] = argv[i];
    }

    string myArg = "'Supplied By " ;
    myArg = myArg + argv[0] + "'"; 

    // ad a constant argument.
    i = argc-1;
    progArgs[i] = strdup("Constant_Arg");

    // add an arugement generated in the program
    i++;
    progArgs[i] = strdup(myArg.c_str());

    // null terminate
    i++;
    progArgs[i] = nullptr;


    for(i=0;i<=argc;i++) {
      cout << argv[0] << ": Arg[" << i << "] is " << progArgs[i] << endl;
    }

    cout << endl;
    cout << argv[0] << " has pid " << getpid() << endl;
    cout << "Running " << argv[1] << endl << endl;

    execve(argv[1], progArgs, progEnv);
    perror("Exec returned");

    return 1;
}