added an implementation for nanosleep() based on snooze()

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22311 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/libroot/posix/time/Jamfile

@@ -12,6 +12,7 @@ MergeObject posix_time.o :
 	ctime.c
 	difftime.c
 	localtime.c
+	nanosleep.c
 	stime.c
 	strftime.c
 	strptime.c

src/system/libroot/posix/time/nanosleep.c

@@ -0,0 +1,35 @@
+/* 
+** Copyright 2007, Jérôme Duval. All rights reserved.
+** Distributed under the terms of the Haiku License.
+*/
+#include <errno.h>
+#include <time.h>
+#include <OS.h>
+
+int
+nanosleep(const struct timespec *rqtp, struct timespec *rmtp)
+{
+	bigtime_t ms, begin_ms;
+	status_t err;
+
+	if (!rqtp) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	// round up tv_nsec
+	ms = rqtp->tv_sec * 1000000LL + (rqtp->tv_nsec + 999) / 1000;
+	begin_ms = system_time();
+	err = snooze(ms);
+	if (err == B_INTERRUPTED) {
+		errno = EINTR;
+		if (rmtp) {
+			bigtime_t remain_ms = ms - system_time() + begin_ms;
+			rmtp->tv_sec = remain_ms / 1000000;
+			rmtp->tv_nsec = (remain_ms - rmtp->tv_sec) * 1000;
+		}
+		return -1;
+	}
+	return 0;
+}
+