From 78beadd60b81c0b3c92eca38890983a672dbfd93 Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Fri, 10 Jul 2015 01:21:28 -0500
Subject: Promote hwclock.

---
 toys/other/hwclock.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 toys/other/hwclock.c

(limited to 'toys/other')

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);
+}
-- 
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