1 /* vi: set sw=4 ts=4: */
3 * nice implementation for busybox
5 * Copyright (C) 2005 Manuel Novoa III <mjn3@codepoet.org>
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
13 //config: nice runs a program with modified scheduling priority.
15 //applet:IF_NICE(APPLET(nice, BB_DIR_BIN, BB_SUID_DROP))
17 //kbuild:lib-$(CONFIG_NICE) += nice.o
19 //usage:#define nice_trivial_usage
20 //usage: "[-n ADJUST] [PROG ARGS]"
21 //usage:#define nice_full_usage "\n\n"
22 //usage: "Change scheduling priority, run PROG\n"
23 //usage: "\n -n ADJUST Adjust priority by ADJUST"
25 #include <sys/resource.h>
28 int nice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
29 int nice_main(int argc, char **argv)
31 int old_priority, adjustment;
33 old_priority = getpriority(PRIO_PROCESS, 0);
35 if (!*++argv) { /* No args, so (GNU) output current nice value. */
36 printf("%d\n", old_priority);
37 fflush_stdout_and_exit(EXIT_SUCCESS);
40 adjustment = 10; /* Set default adjustment. */
42 if (argv[0][0] == '-') {
43 if (argv[0][1] == 'n') { /* -n */
44 if (argv[0][2]) { /* -nNNNN (w/o space) */
45 argv[0] += 2; argv--; argc++;
47 } else { /* -NNN (NNN may be negative) == -n NNN */
48 argv[0] += 1; argv--; argc++;
50 if (argc < 4) { /* Missing priority and/or utility! */
53 adjustment = xatoi_range(argv[1], INT_MIN/2, INT_MAX/2);
57 { /* Set our priority. */
58 int prio = old_priority + adjustment;
60 if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
61 bb_perror_msg_and_die("setpriority(%d)", prio);
65 BB_EXECVP_or_die(argv);