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 *
7USE_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
9config HWCLOCK
10  bool "hwclock"
11  default y
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
28GLOBALS(
29  char *fname;
30
31  int utc;
32)
33
34static 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
57void 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) error_exit("mktime failed");
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)) perror_exit("gettimeofday failed");
103    if (!(TT.utc ? gmtime_r : localtime_r)(&timeval.tv_sec, &tm))
104      error_exit(TT.utc ? "gmtime_r failed" : "localtime_r failed");
105  }
106
107  if (toys.optflags & FLAG_w) {
108    /* The value of tm_isdst will positive if daylight saving time is in effect,
109     * zero if it is not and negative if the information is not available.
110     * todo: so why isn't this negative...? */
111    tm.tm_isdst = 0;
112    xioctl(fd, RTC_SET_TIME, &tm);
113  } else if (toys.optflags & FLAG_s) {
114    tzone.tz_minuteswest = timezone / 60 - 60 * daylight;
115    timeval.tv_sec = time;
116    timeval.tv_usec = 0; // todo: fixit
117  } else if (toys.optflags & FLAG_t) {
118    // Adjust seconds for timezone and daylight saving time
119    // extern long timezone is defined in header sys/time.h
120    tzone.tz_minuteswest = timezone / 60;
121    if (tm.tm_isdst) tzone.tz_minuteswest -= 60;
122    if (!TT.utc) timeval.tv_sec += tzone.tz_minuteswest * 60;
123  } else {
124    char *c = ctime(&time), *s = strrchr(c, '\n');
125
126    if (s) *s = '\0';
127    // TODO: implement this.
128    xprintf("%s  0.000000 seconds\n", c);
129  }
130  if (toys.optflags & (FLAG_t|FLAG_s)) {
131    tzone.tz_dsttime = 0;
132    if (settimeofday(&timeval, &tzone)) perror_exit("settimeofday failed");
133  }
134
135  if (fd != -1) close(fd);
136}
137