time: Introduce function to check correctness of nanoseconds value

The valid_nanoseconds () static inline function has been introduced to
check if nanoseconds value is in the correct range - greater or equal to
zero and less than 1000000000.

The explicit #include <time.h> has been added to files where it was
missing.

The __syscall_slong_t type for ns has been used to avoid issues on x32.

Tested with:
- scripts/build-many-glibcs.py
- make PARALLELMFLAGS="-j12" && make PARALLELMFLAGS="-j12" xcheck on x86_64

1 files changed, 8 insertions, 0 deletions

diff --git a/include/time.h b/include/time.h
index d93b16a781..1f6507ef5f 100644
--- a/include/time.h
+++ b/include/time.h
@@ -236,5 +236,13 @@ valid_timespec64_to_timeval (const struct __timespec64 ts64)
 
   return tv;
 }
+
+/* Check if a value is in the valid nanoseconds range. Return true if
+   it is, false otherwise.  */
+static inline bool
+valid_nanoseconds (__syscall_slong_t ns)
+{
+  return __glibc_likely (0 <= ns && ns < 1000000000);
+}
 #endif
 #endif