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_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  sprintf(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      sprintf(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 is 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