Minimal implementation of clock_gettime function

Author: MedourMehdi

include/bits/time.h

@@ -31,6 +31,7 @@
 #  ifdef __USE_POSIX199309
 /* Identifier for system-wide realtime clock.  */
 #   define CLOCK_REALTIME	0
+#   define CLOCK_MONOTONIC	1
 
 /* Flag to indicate time is absolute.  */
 #   define TIMER_ABSTIME	1

include/time.h

@@ -277,6 +277,8 @@ extern int dysize (int __year) __THROW  __attribute__ ((__const__));
    __THROW.  */
 extern int nanosleep (__const struct timespec *__requested_time,
 		      struct timespec *__remaining);
+
+extern int clock_gettime(clockid_t clock_id, struct timespec *tp);
 # endif
 
 # ifdef __USE_XOPEN_EXTENDED

posix/SRCFILES

@@ -20,6 +20,7 @@ SRCFILES = \
 	glob.c \
 	isfdtype.c \
 	nanosleep.c \
+	clock_gettime.c \
 	posix_fallocate.c \
 	pread.c \
 	pwrite.c \

posix/clock_gettime.c

@@ -0,0 +1,39 @@
+#include <errno.h>
+#include <stdint.h>
+#include <time.h>
+#include <sys/time.h>
+
+static inline int
+realtime_gettime(struct timespec *tp)
+{
+	struct timeval tv;
+	int retval = __gettimeofday(&tv, NULL);
+	if (retval == 0)
+    /* Convert into `timespec'.  */
+		TIMEVAL_TO_TIMESPEC(&tv, tp);
+	return retval;
+}
+
+/* Get current value of CLOCK and store it in TP.  */
+
+__typeof__(clock_gettime) __clock_gettime;
+
+int
+__clock_gettime(clockid_t clock_id, struct timespec *tp)
+{
+	int retval = -1;
+
+	switch (clock_id)
+	{
+		case CLOCK_MONOTONIC:
+		case CLOCK_REALTIME:
+			retval = realtime_gettime(tp);
+		break;
+		default:
+			__set_errno(EINVAL);
+		break;
+    }
+	return retval;
+}
+
+weak_alias (__clock_gettime, clock_gettime)