acmecert: Rationalized invocation.

[utils.git] / notty.c

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>

void usage(void)
{
    fprintf(stderr, "usage: notty PROGRAM [-r] [ARGS...]\n");
}

int main(int argc, char **argv)
{
    int tty, retain;
    int c;
    
    retain = 0;
    while((c = getopt(argc, argv, "r")) >= 0) {
	switch(c) {
	case 'r':
	    retain = 1;
	    break;
	case '?':
	case ':':
	default:
	    usage();
	    exit(1);
	}
    }
    if(argc - optind < 1) {
	usage();
	exit(1);
    }
    if((tty = open("/dev/tty", O_RDWR)) < 0) {
	perror("/dev/tty");
	exit(1);
    }
    if(ioctl(tty, TIOCNOTTY)) {
	perror("TIOCNOTTY");
	exit(1);
    }
    if(retain) {
	if(tty != 3) {
	    dup2(tty, 3);
	    close(tty);
	}
    } else {
	close(tty);
    }
    execvp(argv[optind], argv + optind);
    perror(argv[optind]);
    return(127);
}