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-rw-r--r--libbb/rtc.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/libbb/rtc.c b/libbb/rtc.c
new file mode 100644
index 000000000..4cbf32206
--- /dev/null
+++ b/libbb/rtc.c
@@ -0,0 +1,86 @@
+/*
+ * Common RTC functions
+ */
+
+#include "libbb.h"
+#include "rtc_.h"
+
+#if ENABLE_FEATURE_HWCLOCK_ADJTIME_FHS
+# define ADJTIME_PATH "/var/lib/hwclock/adjtime"
+#else
+# define ADJTIME_PATH "/etc/adjtime"
+#endif
+
+int rtc_adjtime_is_utc(void)
+{
+ int utc = 0;
+ FILE *f = fopen(ADJTIME_PATH, "r");
+
+ if (f) {
+ RESERVE_CONFIG_BUFFER(buffer, 128);
+
+ while (fgets(buffer, sizeof(buffer), f)) {
+ int len = strlen(buffer);
+
+ while (len && isspace(buffer[len - 1]))
+ len--;
+
+ buffer[len] = 0;
+
+ if (strncmp(buffer, "UTC", 3) == 0) {
+ utc = 1;
+ break;
+ }
+ }
+ fclose(f);
+
+ RELEASE_CONFIG_BUFFER(buffer);
+ }
+
+ return utc;
+}
+
+int rtc_xopen(const char *default_rtc, int flags)
+{
+ int rtc;
+
+ if (!default_rtc) {
+ rtc = open("/dev/rtc", flags);
+ if (rtc >= 0)
+ return rtc;
+ rtc = open("/dev/rtc0", flags);
+ if (rtc >= 0)
+ return rtc;
+ default_rtc = "/dev/misc/rtc";
+ }
+
+ return xopen(default_rtc, flags);
+}
+
+time_t rtc_read_time(int fd, int utc)
+{
+ struct tm tm;
+ char *oldtz = 0;
+ time_t t = 0;
+
+ memset(&tm, 0, sizeof(struct tm));
+ xioctl(fd, RTC_RD_TIME, &tm);
+ tm.tm_isdst = -1; /* not known */
+
+ if (utc) {
+ oldtz = getenv("TZ");
+ putenv((char*)"TZ=UTC0");
+ tzset();
+ }
+
+ t = mktime(&tm);
+
+ if (utc) {
+ unsetenv("TZ");
+ if (oldtz)
+ putenv(oldtz - 3);
+ tzset();
+ }
+
+ return t;
+}