git.maemo.org Git - busybox4maemo/blob - libbb/rtc.c

   1 /*
   2  * Common RTC functions
   3  */
   4
   5 #include "libbb.h"
   6 #include "rtc_.h"
   7
   8 #if ENABLE_FEATURE_HWCLOCK_ADJTIME_FHS
   9 # define ADJTIME_PATH "/var/lib/hwclock/adjtime"
  10 #else
  11 # define ADJTIME_PATH "/etc/adjtime"
  12 #endif
  13
  14 int rtc_adjtime_is_utc(void)
  15 {
  16         int utc = 0;
  17         FILE *f = fopen(ADJTIME_PATH, "r");
  18
  19         if (f) {
  20                 RESERVE_CONFIG_BUFFER(buffer, 128);
  21
  22                 while (fgets(buffer, sizeof(buffer), f)) {
  23                         int len = strlen(buffer);
  24
  25                         while (len && isspace(buffer[len - 1]))
  26                                 len--;
  27
  28                         buffer[len] = 0;
  29
  30                         if (strncmp(buffer, "UTC", 3) == 0) {
  31                                 utc = 1;
  32                                 break;
  33                         }
  34                 }
  35                 fclose(f);
  36
  37                 RELEASE_CONFIG_BUFFER(buffer);
  38         }
  39
  40         return utc;
  41 }
  42
  43 int rtc_xopen(const char **default_rtc, int flags)
  44 {
  45         int rtc;
  46
  47         if (!*default_rtc) {
  48                 *default_rtc = "/dev/rtc";
  49                 rtc = open(*default_rtc, flags);
  50                 if (rtc >= 0)
  51                         return rtc;
  52                 *default_rtc = "/dev/rtc0";
  53                 rtc = open(*default_rtc, flags);
  54                 if (rtc >= 0)
  55                         return rtc;
  56                 *default_rtc = "/dev/misc/rtc";
  57         }
  58
  59         return xopen(*default_rtc, flags);
  60 }
  61
  62 time_t rtc_read_time(int fd, int utc)
  63 {
  64         struct tm tm;
  65         char *oldtz = 0;
  66         time_t t = 0;
  67
  68         memset(&tm, 0, sizeof(struct tm));
  69         xioctl(fd, RTC_RD_TIME, &tm);
  70         tm.tm_isdst = -1; /* not known */
  71
  72         if (utc) {
  73                 oldtz = getenv("TZ");
  74                 putenv((char*)"TZ=UTC0");
  75                 tzset();
  76         }
  77
  78         t = mktime(&tm);
  79
  80         if (utc) {
  81                 unsetenv("TZ");
  82                 if (oldtz)
  83                         putenv(oldtz - 3);
  84                 tzset();
  85         }
  86
  87         return t;
  88 }