Control-C in bash ???

[Kerl, John]

Here is some code which is The Wrong Answer (the
right answer being, use Denk's SELF & ELDK and you
will have no worries or problems in life).

Nonetheless, this Wrong Answer is illuminating
in that it shows the essentials of what needs
to happen.




// John Kerl
// Avnet Design Services
// 2002/03/27

// ttyrun.c:
// Runs a program with the terminal set up correctly for job control.
// * Compile with powerpc-linux-gcc ttyrun.c -o ttyrun
// * Run in /etc/rc.whatever as ttyrun {program name} {arguments ...},
//   e.g. /bin/ttyrun /bin/sh.

#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
#include <termios.h>
#include <unistd.h>
#include <sys/ioctl.h>

// ----------------------------------------------------------------
void run_prog(int nargc, char ** nargv, char ** oenvp)
{
        char * envs[] = {
                "HOME=/", "TERM=linux", "PATH=/bin", "LD_LIBRARY_PATH=/lib",
                "PS1=temp# ", 0
        };
        char * nenvp[8];

        nenvp[0] = envs[0];
        nenvp[1] = envs[1];
        nenvp[2] = envs[2];
        nenvp[3] = envs[3];
        nenvp[4] = envs[4];
        nenvp[5] = envs[5];

        if (execve(nargv[0], nargv, oenvp) < 0)
                perror("execve");
}

// ----------------------------------------------------------------
int main(int argc, char ** argv, char ** envp)
{
        char tty_name[] = "/dev/ttyS0";
        int tty_fd;
        int pid;
        int pgrp;
        int ppgrp;
        int ttypgrp = -2;

        if (argc < 2) {
                fprintf(stderr, "Usage: %s {program name}\n", argv[0]);
                exit(1);
        }

        tty_fd = open(tty_name, O_RDWR);
        if (tty_fd < 0) {
                perror("open tty");
                exit(1);
        }

        // Only go through this trouble if the new
        // tty doesn't fall in this process group.
        pid = getpid();
        pgrp = getpgid(0);
        ppgrp = getpgid(getppid());
        if (ioctl(tty_fd, TIOCGPGRP, &ttypgrp) < 0) {
                perror("ioctl TIOCGPGRP");
        }

        if (pgrp != ttypgrp && ppgrp != ttypgrp) {
                if (pid != getsid(0)) {
                        if (pid == getpgid(0))
                                setpgid(0, getpgid(getppid()));
                        setsid();
                }

                signal(SIGHUP, SIG_IGN);
                ioctl(0, TIOCNOTTY, (char *)1);
                signal(SIGHUP, SIG_DFL);
                close(0);
                close(1);
                close(2);
                close(tty_fd);
                tty_fd = open(tty_name, O_RDWR);
                ioctl(0, TIOCSCTTY, (char *)1);
                dup(tty_fd);
                dup(tty_fd);
        }
        else {
                close(tty_fd);
        }

        run_prog(argc - 1, &argv[1], envp);

        return 0;
}





-----Original Message-----
From: Chris Wedgwood [mailto:[EMAIL PROTECTED]
Sent: Monday, January 13, 2003 12:49 PM
To: Mark Chambers
Cc: linuxppc-embedded at lists.linuxppc.org
Subject: Re: Control-C in bash ???



On Mon, Jan 13, 2003 at 02:09:00PM -0500, Mark Chambers wrote:

> On a PC, I can, for instance, enter "ping 192.168.1.4", then hit
> Control-C and stop the ping.  For the life of me, I can't figure out
> how to do the same on my MPC860 system!!!

if you boot init=/bin/sh or whatever and your init/login doesn't set
the tty up, you will need to do it yourself (man stty).


  --cw


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