1/* vi: set sw=4 ts=4: */
2/*
3 * nice implementation for busybox
4 *
5 * Copyright (C) 2005  Manuel Novoa III  <mjn3@codepoet.org>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8 */
9
10#include <sys/resource.h>
11#include "libbb.h"
12
13int nice_main(int argc, char **argv);
14int nice_main(int argc, char **argv)
15{
16	int old_priority, adjustment;
17
18	old_priority = getpriority(PRIO_PROCESS, 0);
19
20	if (!*++argv) {	/* No args, so (GNU) output current nice value. */
21		printf("%d\n", old_priority);
22		fflush_stdout_and_exit(EXIT_SUCCESS);
23	}
24
25	adjustment = 10;			/* Set default adjustment. */
26
27	if (argv[0][0] == '-') {
28		if (argv[0][1] == 'n') { /* -n */
29			if (argv[0][2]) { /* -nNNNN (w/o space) */
30				argv[0] += 2; argv--; argc++;
31			}
32		} else { /* -NNN (NNN may be negative) == -n NNN */
33			argv[0] += 1; argv--; argc++;
34		}
35		if (argc < 4) {			/* Missing priority and/or utility! */
36			bb_show_usage();
37		}
38		adjustment = xatoi_range(argv[1], INT_MIN/2, INT_MAX/2);
39		argv += 2;
40	}
41
42	{  /* Set our priority. */
43		int prio = old_priority + adjustment;
44
45		if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
46			bb_perror_msg_and_die("setpriority(%d)", prio);
47		}
48	}
49
50	BB_EXECVP(*argv, argv);		/* Now exec the desired program. */
51
52	/* The exec failed... */
53	xfunc_error_retval = (errno == ENOENT) ? 127 : 126; /* SUSv3 */
54	bb_perror_msg_and_die("%s", *argv);
55}
56