1 /* hwclock.c - get and set the hwclock
2 *
3 * Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com>
4 *
5 * No standard, but see Documentation/rtc.txt in the linux kernel source..
6 *
7 USE_HWCLOCK(NEWTOY(hwclock, ">0(fast)f(rtc):u(utc)l(localtime)t(systz)s(hctosys)r(show)w(systohc)[-ul][!rtsw]", TOYFLAG_USR|TOYFLAG_BIN))
8
9 config HWCLOCK
10 bool "hwclock"
11 default n
12 help
13 usage: hwclock [-rswtluf]
14
15 -f FILE Use specified device file instead of /dev/rtc (--rtc)
16 -l Hardware clock uses localtime (--localtime)
17 -r Show hardware clock time (--show)
18 -s Set system time from hardware clock (--hctosys)
19 -t Set the system time based on the current timezone (--systz)
20 -u Hardware clock uses UTC (--utc)
21 -w Set hardware clock from system time (--systohc)
22 */
23
24 #define FOR_hwclock
25 #include "toys.h"
26 #include <linux/rtc.h>
27
GLOBALS(char * fname;int utc;)28 GLOBALS(
29 char *fname;
30
31 int utc;
32 )
33
34 static int rtc_find(struct dirtree* node)
35 {
36 FILE *fp;
37
38 if (!node->parent) return DIRTREE_RECURSE;
39
40 snprintf(toybuf, sizeof(toybuf), "/sys/class/rtc/%s/hctosys", node->name);
41 fp = fopen(toybuf, "r");
42 if (fp) {
43 int hctosys = 0, items = fscanf(fp, "%d", &hctosys);
44
45 fclose(fp);
46 if (items == 1 && hctosys == 1) {
47 snprintf(toybuf, sizeof(toybuf), "/dev/%s", node->name);
48 TT.fname = toybuf;
49
50 return DIRTREE_ABORT;
51 }
52 }
53
54 return 0;
55 }
56
hwclock_main()57 void hwclock_main()
58 {
59 struct timezone tzone;
60 struct timeval timeval;
61 struct tm tm;
62 time_t time;
63 int fd = -1;
64
65 // check for Grenich Mean Time
66 if (toys.optflags & FLAG_u) TT.utc = 1;
67 else {
68 FILE *fp;
69 char *s = 0;
70
71 for (fp = fopen("/etc/adjtime", "r");
72 fp && getline(&s, (void *)toybuf, fp)>0;
73 free(s), s = 0) TT.utc += !strncmp(s, "UTC", 3);
74 if (fp) fclose(fp);
75 }
76
77 if (!(toys.optflags&FLAG_t)) {
78 int w = toys.optflags & FLAG_w, flag = O_WRONLY*w;
79
80 // Open /dev/rtc (if your system has no /dev/rtc symlink, search for it).
81 if (!TT.fname && (fd = open("/dev/rtc", flag)) == -1) {
82 dirtree_read("/sys/class/rtc", rtc_find);
83 if (!TT.fname) TT.fname = "/dev/misc/rtc";
84 }
85 if (fd == -1) fd = xopen(TT.fname, flag);
86
87 // Get current time in seconds from rtc device. todo: get subsecond time
88 if (!w) {
89 char *s = s;
90
91 xioctl(fd, RTC_RD_TIME, &tm);
92 if (TT.utc) s = xtzset("UTC0");
93 if ((time = mktime(&tm)) < 0) goto bad;
94 if (TT.utc) {
95 free(xtzset(s));
96 free(s);
97 }
98 }
99 }
100
101 if (toys.optflags & (FLAG_w|FLAG_t))
102 if (gettimeofday(&timeval, 0)
103 || (TT.utc ? gmtime_r : localtime_r)(&timeval.tv_sec, &tm)) goto bad;
104
105 if (toys.optflags & FLAG_w) {
106 /* The value of tm_isdst will positive if daylight saving time is in effect,
107 * zero if it is not and negative if the information is not available.
108 * todo: so why isn't this negative...? */
109 tm.tm_isdst = 0;
110 xioctl(fd, RTC_SET_TIME, &time);
111 } else if (toys.optflags & FLAG_s) {
112 tzone.tz_minuteswest = timezone / 60 - 60 * daylight;
113 timeval.tv_sec = time;
114 timeval.tv_usec = 0; // todo: fixit
115 } else if (toys.optflags & FLAG_t) {
116 // Adjust seconds for timezone and daylight saving time
117 // extern long timezone is defined in header sys/time.h
118 tzone.tz_minuteswest = timezone / 60;
119 if (tm.tm_isdst) tzone.tz_minuteswest -= 60;
120 if (!TT.utc) timeval.tv_sec += tzone.tz_minuteswest * 60;
121 } else {
122 char *c = ctime(&time), *s = strrchr(c, '\n');
123
124 if (s) *s = '\0';
125 // TODO: implement this.
126 xprintf("%s 0.000000 seconds\n", c);
127 }
128 if (toys.optflags & (FLAG_t|FLAG_s)) {
129 tzone.tz_dsttime = 0;
130 if (settimeofday(&timeval, &tzone)) goto bad;
131 }
132
133 if (fd != -1) close(fd);
134
135 return;
136 bad:
137 perror_exit("failed");
138 }
139