[WiiU] Add missing time/clock libc functions

Add some timing functions so that we can know the time (woo-hoo?)
I use errno here, which worries me a bit. I wouldn't put it past
devkitPPC to have it as a null pointer or something.

Can confirm this makes XMB's clock work, much to @cucholix's delight;
I'm sure ;D

frontend/drivers/platform_wiiu.c

@@ -507,11 +507,6 @@ int main(int argc, char **argv)
    return 0;
 }
 
-unsigned long _times_r(struct _reent *r, struct tms *tmsbuf)
-{
-   return 0;
-}
-
 void __eabi(void)
 {
 

wiiu/system/imports.h

@@ -34,6 +34,7 @@ IMPORT(OSGetCoreId);
 IMPORT(OSIsMainCore);
 IMPORT(OSGetSystemTime);
 IMPORT(OSGetSystemTick);
+IMPORT(OSGetTime);
 IMPORT(OSGetSymbolName);
 IMPORT(OSGetSharedData);
 IMPORT(OSEffectiveToPhysical);

wiiu/system/missing_libc_functions.c

@@ -7,6 +7,9 @@
 #include <wiiu/os.h>
 #include <pwd.h>
 #include <features/features_cpu.h>
+#include <sys/reent.h>
+#include <errno.h>
+#include <time.h>
 
 /* This is usually in libogc; we can't use that on wiiu */
 int usleep(useconds_t microseconds) {
@@ -51,11 +54,62 @@ struct passwd* getpwuid(uid_t uid) {
 	return &out;
 }
 
-/* Try to vaugely spoof the POISX clock. Epoch is off by about 30 */
-/* years, so this could be better... */
-/* Only has second accuracy since I'm lazy. */
+/* Basic Cafe OS clock thingy. */
+int _gettimeofday_r(struct _reent *ptr,
+   struct timeval* ptimeval,
+   void* ptimezone) {
+
+   OSTime cosTime;
+   uint64_t cosSecs;
+   uint32_t cosUSecs;
+   time_t unixSecs;
+
+/* We need somewhere to put our output */
+	if (ptimeval == NULL) {
+      errno = EFAULT;
+      return -1;
+   }
+
+/* Get Cafe OS clock in seconds; epoch 2000-01-01 00:00 */
+	cosTime = OSGetTime();
+   cosSecs = ticks_to_sec(cosTime);
+
+/* Get extra milliseconds */
+   cosUSecs = ticks_to_us(cosTime) - (cosSecs * 1000000);
+
+/* Convert to Unix time, epoch 1970-01-01 00:00.
+   Constant value is seconds between 1970 and 2000.
+   time_t is 32bit here, so the Wii U is vulnerable to the 2038 problem. */
+	unixSecs = cosSecs + 946684800;
+
+   ptimeval->tv_sec = unixSecs;
+   ptimeval->tv_usec = cosUSecs;
+   return 0;
+}
+
+/* POSIX clock in all its glory */
 int clock_gettime(clockid_t clk_id, struct timespec* tp) {
-	int64_t time_usec = cpu_features_get_time_usec();
-	tp->tv_sec = time_usec / 1000000;
+   struct timeval ptimeval = { 0 };
+   int ret = 0;
+   OSTime cosTime;
+
+   if (tp == NULL) {
+      errno = EFAULT;
+      return -1;
+   }
+
+   switch (clk_id) {
+      case CLOCK_REALTIME:
+      /* Just wrap gettimeofday. Cheating, I know. */
+         ret = _gettimeofday_r(NULL, &ptimeval, NULL);
+         if (ret) return -1;
+
+         tp->tv_sec = ptimeval.tv_sec;
+         tp->tv_nsec = ptimeval.tv_usec * 1000;
+         break;
+      default:
+         errno = EINVAL;
+         return -1;
+   }
 	return 0;
 }