C11 thread support: address standard compilance issues

Also fixes #158

nx/source/runtime/c11-threads.c

@@ -1,13 +1,47 @@
 #include <stdlib.h>
+#include <time.h>
 #include <threads.h>
 #include "kernel/svc.h"
 #include "../internal.h"
 
+#define THRD_MAIN_HANDLE ((thrd_t)~(uintptr_t)0)
+
+static bool timespec_subtract(struct timespec x, struct timespec y, struct timespec *__restrict result)
+{
+    // Perform the carry for the later subtraction by updating y
+    if (x.tv_nsec < y.tv_nsec) {
+        int seconds = (y.tv_nsec - x.tv_nsec) / 1000000000 + 1;
+        y.tv_nsec -= 1000000000 * seconds;
+        y.tv_sec += seconds;
+    }
+    if (x.tv_nsec - y.tv_nsec > 1000000000) {
+        int seconds = (x.tv_nsec - y.tv_nsec) / 1000000000;
+        y.tv_nsec += 1000000000 * seconds;
+        y.tv_sec -= seconds;
+    }
+
+    // Compute the time remaining to wait
+    result->tv_sec = x.tv_sec - y.tv_sec;
+    result->tv_nsec = x.tv_nsec - y.tv_nsec;
+
+    // Return true if result is negative
+    return x.tv_sec < y.tv_sec;
+}
+
 static inline u64 impl_timespec2nsec(const struct timespec *__restrict ts)
 {
     return (u64)ts->tv_sec * 1000000000 + ts->tv_nsec;
 }
 
+static u64 impl_abstimespec2nsec(const struct timespec *__restrict ts)
+{
+    struct timespec now, diff;
+    clock_gettime(CLOCK_REALTIME, &now);
+    if (timespec_subtract(*ts, now, &diff))
+        return 0;
+    return impl_timespec2nsec(&diff);
+}
+
 void call_once(once_flag *flag, void (*func)(void))
 {
     mtx_lock(&flag->mutex);
@@ -61,11 +95,25 @@ int cnd_signal(cnd_t *cond)
 
 static int __cnd_timedwait(cnd_t *__restrict cond, mtx_t *__restrict mtx, u64 timeout)
 {
-    if (!cond || !mtx || mtx->type != mtx_plain)
+    if (!cond || !mtx)
         return thrd_error;
 
+    uint32_t thread_tag_backup = 0;
+    if (mtx->type & mtx_recursive) {
+        if (mtx->rmutex.counter != 1)
+            return thrd_error;
+        thread_tag_backup = mtx->rmutex.thread_tag;
+        mtx->rmutex.thread_tag = 0;
+        mtx->rmutex.counter = 0;
+    }
+
     Result rc = condvarWaitTimeout(cond, &mtx->mutex, timeout);
 
+    if (mtx->type & mtx_recursive) {
+        mtx->rmutex.thread_tag = thread_tag_backup;
+        mtx->rmutex.counter = 1;
+    }
+
     return R_SUCCEEDED(rc) ? thrd_success : thrd_error;
 }
 
@@ -74,7 +122,7 @@ int cnd_timedwait(cnd_t *__restrict cond, mtx_t *__restrict mtx, const struct ti
     if (!abs_time)
         return thrd_error;
 
-    return __cnd_timedwait(cond, mtx, impl_timespec2nsec(abs_time));
+    return __cnd_timedwait(cond, mtx, impl_abstimespec2nsec(abs_time));
 }
 
 int cnd_wait(cnd_t *cond, mtx_t *mtx)
@@ -89,18 +137,14 @@ void mtx_destroy(mtx_t *mtx)
 
 int mtx_init(mtx_t *mtx, int type)
 {
-    if (!mtx || (type != mtx_plain && type != mtx_recursive))
+    if (!mtx || (type & mtx_timed) || !(type & mtx_plain))
         return thrd_error;
 
     mtx->type = type;
-    switch (type) {
-        case mtx_plain:
-            mutexInit(&mtx->mutex);
-            break;
-        case mtx_recursive:
-            rmutexInit(&mtx->rmutex);
-            break;
-    }
+    if (mtx->type & mtx_recursive)
+        rmutexInit(&mtx->rmutex);
+    else
+        mutexInit(&mtx->mutex);
     return thrd_success;
 }
 
@@ -109,14 +153,10 @@ int mtx_lock(mtx_t *mtx)
     if (!mtx)
         return thrd_error;
 
-    switch (mtx->type) {
-        case mtx_plain:
-            mutexLock(&mtx->mutex);
-            break;
-        case mtx_recursive:
-            rmutexLock(&mtx->rmutex);
-            break;
-    }
+    if (mtx->type & mtx_recursive)
+        rmutexLock(&mtx->rmutex);
+    else
+        mutexLock(&mtx->mutex);
     return thrd_success;
 }
 
@@ -132,14 +172,10 @@ int mtx_trylock(mtx_t *mtx)
         return thrd_error;
 
     bool res = false;
-    switch (mtx->type) {
-        case mtx_plain:
-            res = mutexTryLock(&mtx->mutex);
-            break;
-        case mtx_recursive:
-            res = rmutexTryLock(&mtx->rmutex);
-            break;
-    }
+    if (mtx->type & mtx_recursive)
+        res = rmutexTryLock(&mtx->rmutex);
+    else
+        res = mutexTryLock(&mtx->mutex);
     return res ? thrd_success : thrd_error;
 }
 
@@ -148,14 +184,10 @@ int mtx_unlock(mtx_t *mtx)
     if (!mtx)
         return thrd_error;
 
-    switch (mtx->type) {
-        case mtx_plain:
-            mutexUnlock(&mtx->mutex);
-            break;
-        case mtx_recursive:
-            rmutexUnlock(&mtx->rmutex);
-            break;
-    }
+    if (mtx->type & mtx_recursive)
+        rmutexUnlock(&mtx->rmutex);
+    else
+        mutexUnlock(&mtx->mutex);
     return thrd_success;
 }
 
@@ -237,7 +269,8 @@ _error1:
 
 thrd_t thrd_current(void)
 {
-    return (thrd_t)getThreadVars()->thread_ptr;
+    Thread* t = getThreadVars()->thread_ptr;
+    return t ? (thrd_t)t : THRD_MAIN_HANDLE;
 }
 
 /*
@@ -248,7 +281,7 @@ int thrd_detach(thrd_t thr)
 
 int thrd_equal(thrd_t thr1, thrd_t thr2)
 {
-    return thr1 && thr2 && thr1->thr.handle == thr2->thr.handle;
+    return thr1 == thr2;
 }
 
 void thrd_exit(int res)
@@ -261,6 +294,8 @@ void thrd_exit(int res)
 int thrd_join(thrd_t thr, int *res)
 {
     Result rc;
+    if (!thr || thr == THRD_MAIN_HANDLE)
+        return thrd_error;
 
     rc = threadWaitForExit(&thr->thr);
     if (R_FAILED(rc))