1 files changed, 41 insertions, 40 deletions

diff --git a/toys/other/hwclock.c b/toys/other/hwclock.c
index 4087ec93..5186a2d1 100644
--- a/toys/other/hwclock.c
+++ b/toys/other/hwclock.c
@@ -2,27 +2,35 @@
  *
  * Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com>
  *
- * No standard, but see Documentation/rtc.txt in the linux kernel source..
+ * No standard, but see Documentation/rtc.txt in the linux kernel source.
  *
+ * TODO: get/set subsecond time
 USE_HWCLOCK(NEWTOY(hwclock, ">0(fast)f(rtc):u(utc)l(localtime)t(systz)s(hctosys)r(show)w(systohc)[-ul][!rtsw]", TOYFLAG_SBIN))
 
 config HWCLOCK
   bool "hwclock"
   default y
   help
-    usage: hwclock [-rswtluf]
+    usage: hwclock [-rswtlu] [-f FILE]
 
-    Get/set the hardware clock.
+    Get/set the hardware clock. Default is hwclock -ruf /dev/rtc0
 
-    -f FILE	Use specified device file instead of /dev/rtc0 (--rtc)
+    -f	Use specified device FILE instead of /dev/rtc0 (--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)
+    -t	Inform kernel of non-UTC clock's timezone so it returns UTC (--systz)
     -u	Hardware clock uses UTC (--utc)
     -w	Set hardware clock from system time (--systohc)
 */
 
+
+// Bug workaround for musl commit 5a105f19b5aa which removed a symbol the
+// kernel headers have. (Can't copy it here, varies wildly by architecture.)
+#if __has_include(<asm/unistd.h>)
+#include <asm/unistd.h>
+#endif
+
 #define FOR_hwclock
 #include "toys.h"
 #include <linux/rtc.h>
@@ -31,58 +39,51 @@ GLOBALS(
   char *f;
 )
 
+// Bug workaround for musl commit 2c2c3605d3b3 which rewrote the syscall
+// wrapper to not use the syscall, which is the only way to set kernel's sys_tz
+#define settimeofday(x, tz) syscall(__NR_settimeofday, (void *)0, (void *)tz)
+
 void hwclock_main()
 {
-  struct timezone tzone;
-  struct timeval timeval;
+  struct timezone tz = {0};
+  struct timespec ts = {0};
   struct tm tm;
-  int fd = -1, utc;
+  int fd = -1;
 
-  if (FLAG(u)) utc = 1;
-  else if (FLAG(l)) utc = 0;
-  else utc = !readfile("/etc/adjtime", toybuf, sizeof(toybuf)) ||
-    !!strstr(toybuf, "UTC");
+  // -t without -u implies -l
+  if (FLAG(t)&&!FLAG(u)) toys.optflags |= FLAG_l;
+  if (FLAG(l)) {
+    // sets globals timezone and daylight from sys/time.h
+    // Handle dst adjustment ourselves. (Rebooting during dst transition is
+    // just conceptually unpleasant, linux uses UTC for a reason.)
+    tzset();
+    tz.tz_minuteswest = timezone/60 - 60*daylight;
+  }
 
   if (!FLAG(t)) {
-    if (!TT.f) TT.f = "/dev/rtc0";
-    fd = xopen(TT.f, O_WRONLY*FLAG(w));
+    fd = xopen(TT.f ? : "/dev/rtc0", O_WRONLY*FLAG(w));
 
-    // Get current time in seconds from rtc device. TODO: get subsecond time
+    // Get current time in seconds from rtc device.
     if (!FLAG(w)) {
       xioctl(fd, RTC_RD_TIME, &tm);
-      timeval.tv_sec = xmktime(&tm, utc);
-      timeval.tv_usec = 0; // TODO: fixit
+      ts.tv_sec = xmktime(&tm, !FLAG(l));
     }
   }
 
   if (FLAG(w) || FLAG(t)) {
-    if (gettimeofday(&timeval, 0)) perror_exit("gettimeofday failed");
-    if (!(utc ? gmtime_r : localtime_r)(&timeval.tv_sec, &tm))
-      error_exit(utc ? "gmtime_r failed" : "localtime_r failed");
-  }
-
-  if (FLAG(w)) {
-    /* The value of tm_isdst is 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);
+    if (FLAG(w)) {
+      if (clock_gettime(CLOCK_REALTIME, &ts)) perror_exit("clock_gettime");
+      if (!(FLAG(l) ? localtime_r : gmtime_r)(&ts.tv_sec, &tm))
+        error_exit("%s failed", FLAG(l) ? "localtime_r" : "gmtime_r");
+      xioctl(fd, RTC_SET_TIME, &tm);
+    }
+    if (settimeofday(0, &tz)) perror_exit("settimeofday");
   } else if (FLAG(s)) {
-    tzone.tz_minuteswest = timezone / 60 - 60 * daylight;
-  } else if (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 (!utc) timeval.tv_sec += tzone.tz_minuteswest * 60;
+    if (clock_settime(CLOCK_REALTIME, &ts)) perror_exit("clock_settime");
   } else {
     strftime(toybuf, sizeof(toybuf), "%F %T%z", &tm);
     xputs(toybuf);
   }
-  if (FLAG(t) || FLAG(s)) {
-    tzone.tz_dsttime = 0;
-    if (settimeofday(&timeval, &tzone)) perror_exit("settimeofday failed");
-  }
 
-  xclose(fd);
+  if (CFG_TOYBOX_FREE) xclose(fd);
 }