LXR toybox/toys/other/hwclock.c

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