Run bash as a child process in C having same effect as do ssh has

[abhimanyu]

I want to run bash as child process of my C program.
Few conditions
1) My program will handle both STDIN and STDOUT of bash.
2) No care about practical use.

I have done it but it does not looks like bash.

Here is my code

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/wait.h>

// for tunneling the data
struct tnl {
    int in;
    int out;
};

// for tunneling the data
void *do_tnl(void *ptr);

int main(int argc,char **argv) {
    int p1[2];
    int p2[2];
    pipe(p1);
    pipe(p2);
    int c_pid = fork();
    if (c_pid == 0) {
        // child        
        dup2(p1[0], 0);
        close(p1[1]);
        dup2(p2[1], 1);
        close(p2[0]);
        char *argv1[2];
        argv1[0]=argv[1];
        argv1[1]=NULL;
        execvp(argv[1], argv1);
    } else {
        // parent
        close(p1[0]);
        close(p2[1]);
        struct tnl t1;
        t1.in = 0;
        t1.out = p1[1];
        struct tnl t2;
        t2.in = p2[0];
        t2.out = 1;

        pthread_t thread1, thread2;
        int iret1, iret2;
        iret1 = pthread_create(&thread1, NULL, do_tnl, (void*) &t1);
        iret2 = pthread_create(&thread2, NULL, do_tnl, (void*) &t2);
        pthread_join(thread1, NULL);
        pthread_join(thread2, NULL);
        printf("Thread 1 returns: %d\n", iret1);
        printf("Thread 2 returns: %d\n", iret2);
        int st;
        wait(&st);
    }
    return 0;
}

void *do_tnl(void *ptr) {
    struct tnl *t = ptr;
    while (1) {
        int buf[1];
        int r = read(t->in, buf, 1);
        if (r > 0) {
            write(t->out, buf, 1);
        } else {
            break;
        }
    }
}

// Run example
[u123<at>Sohani ~]$ ./myprog /bin/bash
pwd
/home/u123
who
u123 :0 2013-01-16 03:31 (:0)
u123 pts/0 2013-01-18 23:23 (:0)
u123 pts/1 2013-01-19 03:04 (:0)
u123 pts/3 2013-01-19 02:31 (:0)
exit

[u123<at>Sohani ~]$
// Run example end
So as you can see that it is working. I can now run any command(e.g. here I tun pwd, who, exit). But the problem is that
1) The output is not color full.
2) There is no "[u123<at>Sohani ~]$" part in bash.

So I want the same effect as it happen when I run bash normally in terminal.

I am sure that it is possible because I can run a ssh-server(sshd) and ssh-client(ssh) with normal privilege and there I have bash running like it run normally.

I have searched on net. And openssh code is too large.

<at>: It is actually ascii chracter having value 64 (decimal)
It denied to have such character.

So please help.
Thanks in advance.

[alf55]

When you ssh to a host, you create a login session on that computer (even if it is localhost) and it executes the application passed (defaults to the specified shell for the login on the remote host). In your c program, you are running a shell that is not a login shell and hence "$PS1" does not get set (also lack of interactive may also enter the picture as well).