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-rw-r--r--toys/other/hwclock.c136
1 files changed, 136 insertions, 0 deletions
diff --git a/toys/other/hwclock.c b/toys/other/hwclock.c
new file mode 100644
index 00000000..75e06416
--- /dev/null
+++ b/toys/other/hwclock.c
@@ -0,0 +1,136 @@
+/* hwclock.c - get and set the hwclock
+ *
+ * Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com>
+ *
+ * No standard, but see Documentation/rtc.txt in the linux kernel source..
+ *
+USE_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))
+
+config HWCLOCK
+ bool "hwclock"
+ default y
+ help
+ usage: hwclock [-rswtluf]
+
+ -f FILE Use specified device file instead of /dev/rtc (--rtc)
+ -l Hardware clock uses localtime (--localtime)
+ -r Show hardware clock time (--show)
+ -s Set system time from hardware clock (--hctosys)
+ -t Set the system time based on the current timezone (--systz)
+ -u Hardware clock uses UTC (--utc)
+ -w Set hardware clock from system time (--systohc)
+*/
+
+#define FOR_hwclock
+#include "toys.h"
+#include <linux/rtc.h>
+
+GLOBALS(
+ char *fname;
+
+ int utc;
+)
+
+static int rtc_find(struct dirtree* node)
+{
+ FILE *fp;
+
+ if (!node->parent) return DIRTREE_RECURSE;
+
+ snprintf(toybuf, sizeof(toybuf), "/sys/class/rtc/%s/hctosys", node->name);
+ fp = fopen(toybuf, "r");
+ if (fp) {
+ int hctosys = 0, items = fscanf(fp, "%d", &hctosys);
+
+ fclose(fp);
+ if (items == 1 && hctosys == 1) {
+ snprintf(toybuf, sizeof(toybuf), "/dev/%s", node->name);
+ TT.fname = toybuf;
+
+ return DIRTREE_ABORT;
+ }
+ }
+
+ return 0;
+}
+
+void hwclock_main()
+{
+ struct timezone tzone;
+ struct timeval timeval;
+ struct tm tm;
+ time_t time;
+ int fd = -1;
+
+ // check for Grenich Mean Time
+ if (toys.optflags & FLAG_u) TT.utc = 1;
+ else {
+ FILE *fp;
+ char *s = 0;
+
+ for (fp = fopen("/etc/adjtime", "r");
+ fp && getline(&s, (void *)toybuf, fp)>0;
+ free(s), s = 0) TT.utc += !strncmp(s, "UTC", 3);
+ if (fp) fclose(fp);
+ }
+
+ if (!(toys.optflags&FLAG_t)) {
+ int w = toys.optflags & FLAG_w, flag = O_WRONLY*w;
+
+ // Open /dev/rtc (if your system has no /dev/rtc symlink, search for it).
+ if (!TT.fname && (fd = open("/dev/rtc", flag)) == -1) {
+ dirtree_read("/sys/class/rtc", rtc_find);
+ if (!TT.fname) TT.fname = "/dev/misc/rtc";
+ }
+ if (fd == -1) fd = xopen(TT.fname, flag);
+
+ // Get current time in seconds from rtc device. todo: get subsecond time
+ if (!w) {
+ char *s = s;
+
+ xioctl(fd, RTC_RD_TIME, &tm);
+ if (TT.utc) s = xtzset("UTC0");
+ if ((time = mktime(&tm)) < 0) error_exit("mktime failed");
+ if (TT.utc) {
+ free(xtzset(s));
+ free(s);
+ }
+ }
+ }
+
+ if (toys.optflags & (FLAG_w|FLAG_t)) {
+ if (gettimeofday(&timeval, 0)) perror_exit("gettimeofday failed");
+ if (!(TT.utc ? gmtime_r : localtime_r)(&timeval.tv_sec, &tm))
+ error_exit(TT.utc ? "gmtime_r failed" : "localtime_r failed");
+ }
+
+ if (toys.optflags & FLAG_w) {
+ /* The value of tm_isdst will positive if daylight saving time is in effect,
+ * zero if it is not and negative if the information is not available.
+ * todo: so why isn't this negative...? */
+ tm.tm_isdst = 0;
+ xioctl(fd, RTC_SET_TIME, &tm);
+ } else if (toys.optflags & FLAG_s) {
+ tzone.tz_minuteswest = timezone / 60 - 60 * daylight;
+ timeval.tv_sec = time;
+ timeval.tv_usec = 0; // todo: fixit
+ } else if (toys.optflags & FLAG_t) {
+ // Adjust seconds for timezone and daylight saving time
+ // extern long timezone is defined in header sys/time.h
+ tzone.tz_minuteswest = timezone / 60;
+ if (tm.tm_isdst) tzone.tz_minuteswest -= 60;
+ if (!TT.utc) timeval.tv_sec += tzone.tz_minuteswest * 60;
+ } else {
+ char *c = ctime(&time), *s = strrchr(c, '\n');
+
+ if (s) *s = '\0';
+ // TODO: implement this.
+ xprintf("%s 0.000000 seconds\n", c);
+ }
+ if (toys.optflags & (FLAG_t|FLAG_s)) {
+ tzone.tz_dsttime = 0;
+ if (settimeofday(&timeval, &tzone)) perror_exit("settimeofday failed");
+ }
+
+ if (fd != -1) close(fd);
+}