1 /* vi: set sw=4 ts=4: */
2 /*
3 * usleep implementation for busybox
4 *
5 * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 */
9 //config:config USLEEP
10 //config: bool "usleep (1.3 kb)"
11 //config: default y
12 //config: help
13 //config: usleep is used to pause for a specified number of microseconds.
14
15 //applet:IF_USLEEP(APPLET_NOFORK(usleep, usleep, BB_DIR_BIN, BB_SUID_DROP, usleep))
16
17 //kbuild:lib-$(CONFIG_USLEEP) += usleep.o
18
19 /* BB_AUDIT SUSv3 N/A -- Apparently a busybox extension. */
20
21 //usage:#define usleep_trivial_usage
22 //usage: "N"
23 //usage:#define usleep_full_usage "\n\n"
24 //usage: "Pause for N microseconds"
25 //usage:
26 //usage:#define usleep_example_usage
27 //usage: "$ usleep 1000000\n"
28 //usage: "[pauses for 1 second]\n"
29
30 #include "libbb.h"
31
32 /* This is a NOFORK applet. Be very careful! */
33
34 int usleep_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
usleep_main(int argc UNUSED_PARAM,char ** argv)35 int usleep_main(int argc UNUSED_PARAM, char **argv)
36 {
37 if (!argv[1]) {
38 bb_show_usage();
39 }
40
41 /* Safe wrt NOFORK? (noforks are not allowed to run for
42 * a long time). Try "usleep 99999999" + ^C + "echo $?"
43 * in hush with FEATURE_SH_NOFORK=y.
44 * At least on uclibc, usleep() thanslates to nanosleep()
45 * which returns early on any signal (even caught one),
46 * and uclibc does not loop back on EINTR.
47 */
48 usleep(xatou(argv[1]));
49
50 return EXIT_SUCCESS;
51 }
52