posix: timers: use newly added timespec util functions

Use the newly added timespec util functions to manipulate and
compare timespec structures with overflow detection.

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>

Author: Chris Friedt

lib/posix/options/clock_common.c

@@ -15,6 +15,7 @@
 #include <zephyr/posix/unistd.h>
 #include <zephyr/internal/syscall_handler.h>
 #include <zephyr/sys/sem.h>
+#include <zephyr/sys/timeutil.h>
 
 /*
  * `k_uptime_get` returns a timestamp based on an always increasing
@@ -82,11 +83,10 @@ int z_clock_gettime(clockid_t clock_id, struct timespec *ts)
 	/* For ns 32 bit conversion can be used since its smaller than 1sec. */
 	ts->tv_nsec = (int32_t)k_ticks_to_ns_floor32(nremainder);
 
-	ts->tv_sec += base.tv_sec;
-	ts->tv_nsec += base.tv_nsec;
-	if (ts->tv_nsec >= NSEC_PER_SEC) {
-		ts->tv_sec++;
-		ts->tv_nsec -= NSEC_PER_SEC;
+	if (unlikely(timespec_normalize_overflow(ts)) ||
+	    unlikely(timespec_add_overflow(ts, &base))) {
+		errno = EOVERFLOW;
+		return -1;
 	}
 
 	return 0;
@@ -101,7 +101,7 @@ int z_clock_settime(clockid_t clock_id, const struct timespec *tp)
 		return -1;
 	}
 
-	if (tp->tv_nsec < 0 || tp->tv_nsec >= NSEC_PER_SEC) {
+	if (!timespec_is_valid(tp)) {
 		errno = EINVAL;
 		return -1;
 	}
@@ -112,6 +112,11 @@ int z_clock_settime(clockid_t clock_id, const struct timespec *tp)
 	base.tv_sec = delta / NSEC_PER_SEC;
 	base.tv_nsec = delta % NSEC_PER_SEC;
 
+	if (unlikely(timespec_normalize_overflow(&base))) {
+		errno = EOVERFLOW;
+		return -1;
+	}
+
 	SYS_SEM_LOCK(&rt_clock_base_lock) {
 		rt_clock_base = base;
 	}
@@ -137,7 +142,7 @@ int z_clock_nanosleep(clockid_t clock_id, int flags, const struct timespec *rqtp
 		return -1;
 	}
 
-	if ((rqtp->tv_sec < 0) || (rqtp->tv_nsec < 0) || (rqtp->tv_nsec >= NSEC_PER_SEC)) {
+	if ((rqtp->tv_sec < 0) || !timespec_is_valid(rqtp)) {
 		errno = EINVAL;
 		return -1;
 	}

lib/posix/options/posix_clock.h

@@ -16,19 +16,14 @@
 #include <zephyr/sys_clock.h>
 #include <zephyr/sys/__assert.h>
 #include <zephyr/posix/sys/time.h>
+#include <zephyr/sys/timeutil.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /** @cond INTERNAL_HIDDEN */
 
-static inline bool timespec_is_valid(const struct timespec *ts)
-{
-	__ASSERT_NO_MSG(ts != NULL);
-	return (ts->tv_nsec >= 0) && (ts->tv_nsec < NSEC_PER_SEC);
-}
-
 static inline int64_t ts_to_ns(const struct timespec *ts)
 {
 	return ts->tv_sec * NSEC_PER_SEC + ts->tv_nsec;
@@ -47,7 +42,7 @@ static inline void tv_to_ts(const struct timeval *tv, struct timespec *ts)
 
 static inline bool tp_ge(const struct timespec *a, const struct timespec *b)
 {
-	return ts_to_ns(a) >= ts_to_ns(b);
+	return timespec_compare(a, b) >= 0;
 }
 
 static inline int64_t tp_diff(const struct timespec *a, const struct timespec *b)