ubase/mesg.c

54 lines
861 B
C

/* See LICENSE file for copyright and license details. */
#include <sys/stat.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "util.h"
static void
usage(void)
{
eprintf("usage: %s [n|y]\n", argv0);
}
int
main(int argc, char *argv[])
{
struct stat sb;
mode_t mode;
ARGBEGIN {
default:
usage();
} ARGEND;
if (argc > 1)
usage();
if (isatty(2) == 0)
eprintf("stderr: not a tty\n");
if (fstat(2, &sb) < 0)
eprintf("fstat stderr:");
if (argc == 0) {
puts(sb.st_mode & (S_IWGRP | S_IWOTH) ? "is y" : "is n");
return 0;
}
if (argv[0][0] == 'y' && argv[0][1] == '\0')
mode = sb.st_mode | S_IWGRP | S_IWOTH;
else if (argv[0][0] == 'n' && argv[0][1] == '\0')
mode = sb.st_mode & ~(S_IWGRP | S_IWOTH);
else
usage();
if (fchmod(2, mode) < 0)
eprintf("fchmod stderr:");
return 0;
}