get/setpriority() and fsync() system calls

lib/posix/priority.c

@@ -0,0 +1,46 @@
+/*
+priority.c
+*/
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/resource.h>
+#include <lib.h>
+#include <unistd.h>
+#include <string.h>
+#include <stddef.h>
+
+
+int getpriority(int which, int who)
+{
+	int v;
+	message m;
+
+	m.m1_i1 = which;
+	m.m1_i2 = who;
+
+	/* GETPRIORITY returns negative for error.
+	 * Otherwise, it returns the priority plus the minimum
+	 * priority, to distiginuish from error. We have to
+	 * correct for this. (The user program has to check errno
+	 * to see if something really went wrong.)
+	 */
+
+	if((v = _syscall(MM, GETPRIORITY, &m)) < 0) {
+		return v;
+	}
+
+	return v + PRIO_MIN;
+}
+
+int setpriority(int which, int who, int prio)
+{
+	message m;
+
+	m.m1_i1 = which;
+	m.m1_i2 = who;
+	m.m1_i3 = prio;
+
+	return _syscall(MM, SETPRIORITY, &m);
+}
+