xref: /netbsd-src/sys/modules/examples/current_time/current_time.c (revision e6494e6f4f6884b942f7bf578c815ba3a179f185)
1 /*	$NetBSD: current_time.c,v 1.2 2020/04/04 23:22:12 kamil Exp $  */
2 
3 /*-
4  * Copyright (c) 2020 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26  * POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: current_time.c,v 1.2 2020/04/04 23:22:12 kamil Exp $");
31 
32 #include <sys/param.h>
33 #include <sys/module.h>
34 #include <dev/clock_subr.h>
35 
36 /*
37  * Function print_time() fetches the epoch seconds/unix time from the
38  * getmicrotime() function and sends its to clock_secs_to_ymdhms(..) in
39  * dev/clock_subr to parse it into readable date and time format and print it.
40  *
41  * Please note that the current time is printed in GMT/UTC because the kernel
42  * doesn't have the notion of local timezones.
43  */
44 
45 static void
print_current_time(void)46 print_current_time(void)
47 {
48 	struct timeval tv;
49 	struct clock_ymdhms dt;
50 	const char *w_day[] = {
51 		"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",
52 		"Friday", "Saturday"
53 	};
54 
55 	getmicrotime(&tv);
56 	clock_secs_to_ymdhms(tv.tv_sec, &dt);
57 
58 	printf("Current Time: %s, %04" PRIu64 "/%02" PRIu8 "/%02" PRIu8
59 	    " %02" PRIu8 ":%02" PRIu8 ":%02" PRIu8 " UTC\n",
60 	    w_day[dt.dt_wday], dt.dt_year, dt.dt_mon, dt.dt_day, dt.dt_hour,
61 	    dt.dt_min, dt.dt_sec);
62 }
63 
64 MODULE(MODULE_CLASS_MISC, current_time, NULL);
65 
66 static int
current_time_modcmd(modcmd_t cmd,void * arg __unused)67 current_time_modcmd(modcmd_t cmd, void *arg __unused)
68 {
69 	switch (cmd) {
70 	case MODULE_CMD_INIT:
71 		printf("current_time example module loaded.\n");
72 		print_current_time();
73 		break;
74 	case MODULE_CMD_FINI:
75 		printf("current_time example module unloaded.\n");
76 		break;
77 	default:
78 		return ENOTTY;
79 	}
80 
81 	return 0;
82 }
83