usr/src/usr.bin/tn3270/sys_curses/system.c

#include <sys/wait.h>

#include <stdio.h>

#include "../general/general.h"
#include "../api/api.h"

#include "../general/globals.h"


static int shell_pid = 0;

static int
child_died()
{
    union wait *status;

    while ((pid = wait3(status, WNOHANG, 0)) > 0) {
        if (pid == shell_pid) {
            shell_active = 0;
        }
    }
    signal(SIGCHLD, child_died);
}

/*
 * shell_continue() actually runs the command, and looks for API
 * requests coming back in.
 *
 * We are called from the main loop in telnet.c.
 */

int
shell_continue()
{
    return shell_active;
}


/*
 * Called from telnet.c to fork a lower command.com.  We
 * use the spint... routines so that we can pick up
 * interrupts generated by application programs.
 */


int
shell(argc,argv)
int     argc;
char    *argv[];
{
    if ((shell_pid = fork()) {
        shell_active = 1;               /* We are running down below */
        child_killed();                 /* Start up signal handler */
    } else {                            /* New process */
        register int i;

        for (i = 3; i < 30; i++) {
            (void) close(i);
        }
        if (argc == 1) {                /* Just get a shell */
            char *cmdname;

            cmdname = getenv("SHELL");
            execlp(cmdname, cmdname, 0);
            perror("Exec'ing new shell...\n");
            exit(1);
        } else {
            execvp(argv[1], &argv[1]);
            perror("Exec'ing command.\n");
            exit(1);
        }
        /*NOTREACHED*/
    }
    return 1;                   /* Go back to main loop */
}