1/* vi: set sw=4 ts=4: */
2/*
3 * Mini hwclock implementation for busybox
4 *
5 * Copyright (C) 2002 Robert Griebl <griebl@gmx.de>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8*/
9
10#include <sys/utsname.h>
11#include <getopt.h>
12#include "libbb.h"
13
14/* Copied from linux/rtc.h to eliminate the kernel dependency */
15struct linux_rtc_time {
16	int tm_sec;
17	int tm_min;
18	int tm_hour;
19	int tm_mday;
20	int tm_mon;
21	int tm_year;
22	int tm_wday;
23	int tm_yday;
24	int tm_isdst;
25};
26
27#define RTC_SET_TIME   _IOW('p', 0x0a, struct linux_rtc_time) /* Set RTC time    */
28#define RTC_RD_TIME    _IOR('p', 0x09, struct linux_rtc_time) /* Read RTC time   */
29
30#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
31# ifndef _GNU_SOURCE
32#  define _GNU_SOURCE
33# endif
34#endif
35
36static const char *rtcname;
37
38static int xopen_rtc(int flags)
39{
40	int rtc;
41
42	if (!rtcname) {
43		rtc = open("/dev/rtc", flags);
44		if (rtc >= 0)
45			return rtc;
46		rtc = open("/dev/rtc0", flags);
47		if (rtc >= 0)
48			return rtc;
49		rtcname = "/dev/misc/rtc";
50	}
51	return xopen(rtcname, flags);
52}
53
54static time_t read_rtc(int utc)
55{
56	struct tm tm;
57	char *oldtz = 0;
58	time_t t = 0;
59	int rtc = xopen_rtc(O_RDONLY);
60
61	memset(&tm, 0, sizeof(struct tm));
62	xioctl(rtc, RTC_RD_TIME, &tm);
63	tm.tm_isdst = -1; /* not known */
64
65	close(rtc);
66
67	if (utc) {
68		oldtz = getenv("TZ");
69		putenv((char*)"TZ=UTC0");
70		tzset();
71	}
72
73	t = mktime(&tm);
74
75	if (utc) {
76		unsetenv("TZ");
77		if (oldtz)
78			putenv(oldtz - 3);
79		tzset();
80	}
81	return t;
82}
83
84static void write_rtc(time_t t, int utc)
85{
86	struct tm tm;
87	int rtc = xopen_rtc(O_WRONLY);
88
89	tm = *(utc ? gmtime(&t) : localtime(&t));
90	tm.tm_isdst = 0;
91
92	xioctl(rtc, RTC_SET_TIME, &tm);
93
94	close(rtc);
95}
96
97static void show_clock(int utc)
98{
99	//struct tm *ptm;
100	time_t t;
101	char *cp;
102
103	t = read_rtc(utc);
104	//ptm = localtime(&t);  /* Sets 'tzname[]' */
105
106	cp = ctime(&t);
107	if (cp[0])
108		cp[strlen(cp) - 1] = '\0';
109
110	//printf("%s  %.6f seconds %s\n", cp, 0.0, utc ? "" : (ptm->tm_isdst ? tzname[1] : tzname[0]));
111	printf("%s  0.000000 seconds\n", cp);
112}
113
114static void to_sys_clock(int utc)
115{
116	struct timeval tv;
117	const struct timezone tz = { timezone/60 - 60*daylight, 0 };
118
119	tv.tv_sec = read_rtc(utc);
120	tv.tv_usec = 0;
121	if (settimeofday(&tv, &tz))
122		bb_perror_msg_and_die("settimeofday() failed");
123}
124
125static void from_sys_clock(int utc)
126{
127	struct timeval tv;
128
129	gettimeofday(&tv, NULL);
130	//if (gettimeofday(&tv, NULL))
131	//	bb_perror_msg_and_die("gettimeofday() failed");
132	write_rtc(tv.tv_sec, utc);
133}
134
135#if ENABLE_FEATURE_HWCLOCK_ADJTIME_FHS
136# define ADJTIME_PATH "/var/lib/hwclock/adjtime"
137#else
138# define ADJTIME_PATH "/etc/adjtime"
139#endif
140static int check_utc(void)
141{
142	int utc = 0;
143	FILE *f = fopen(ADJTIME_PATH, "r");
144
145	if (f) {
146		RESERVE_CONFIG_BUFFER(buffer, 128);
147
148		while (fgets(buffer, sizeof(buffer), f)) {
149			int len = strlen(buffer);
150
151			while (len && isspace(buffer[len - 1]))
152				len--;
153
154			buffer[len] = 0;
155
156			if (strncmp(buffer, "UTC", 3) == 0) {
157				utc = 1;
158				break;
159			}
160		}
161		fclose(f);
162		RELEASE_CONFIG_BUFFER(buffer);
163	}
164	return utc;
165}
166
167#define HWCLOCK_OPT_LOCALTIME   0x01
168#define HWCLOCK_OPT_UTC         0x02
169#define HWCLOCK_OPT_SHOW        0x04
170#define HWCLOCK_OPT_HCTOSYS     0x08
171#define HWCLOCK_OPT_SYSTOHC     0x10
172#define HWCLOCK_OPT_RTCFILE     0x20
173
174int hwclock_main(int argc, char **argv);
175int hwclock_main(int argc, char **argv)
176{
177	unsigned opt;
178	int utc;
179
180#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
181	static const char hwclock_longopts[] ALIGN1 =
182		"localtime\0" No_argument "l"
183		"utc\0"       No_argument "u"
184		"show\0"      No_argument "r"
185		"hctosys\0"   No_argument "s"
186		"systohc\0"   No_argument "w"
187		"file\0"      Required_argument "f"
188		;
189	applet_long_options = hwclock_longopts;
190#endif
191	opt_complementary = "r--ws:w--rs:s--wr:l--u:u--l";
192	opt = getopt32(argv, "lurswf:", &rtcname);
193
194	/* If -u or -l wasn't given check if we are using utc */
195	if (opt & (HWCLOCK_OPT_UTC | HWCLOCK_OPT_LOCALTIME))
196		utc = opt & HWCLOCK_OPT_UTC;
197	else
198		utc = check_utc();
199
200	if (opt & HWCLOCK_OPT_HCTOSYS) {
201		to_sys_clock(utc);
202		return 0;
203	}
204	if (opt & HWCLOCK_OPT_SYSTOHC) {
205		from_sys_clock(utc);
206		return 0;
207	}
208	/* default HWCLOCK_OPT_SHOW */
209	show_clock(utc);
210	return 0;
211}
212