Add rtcwake.

Some of the bringup folks are debugging RTC issues and asked for this.

Rather than duplicate the weird xtzset dance with mktime, I've factored
that out into a new xmktime that takes a boolean for whether to use UTC
or local time.

Otherwise, the slight cleanup of hwclock.c is entirely optional. The
only functional change there is that util-linux 2.34's hwclock uses ISO
time format, which is the usual toybox preference anyway, so I've
switched it over to that rather than ctime(3).

Bug: http://b/152042947

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/xwrap.c b/lib/xwrap.c
index 555fbd5e..5f18f295 100644
--- a/lib/xwrap.c
+++ b/lib/xwrap.c
@@ -1077,3 +1077,16 @@ char *xgetline(FILE *fp, int *len)
 
   return new;
 }
+
+time_t xmktime(struct tm *tm, int utc)
+{
+  char *old_tz = utc ? xtzset("UTC0") : 0;
+  time_t result;
+
+  if ((result = mktime(tm)) < 0) error_exit("mktime");
+  if (utc) {
+    free(xtzset(old_tz));
+    free(old_tz);
+  }
+  return result;
+}