syscalls: nanosleep

kernel-src/sys/syscalls/sleep.c

@@ -0,0 +1,46 @@
+#include <kernel/syscalls.h>
+#include <time.h>
+#include <kernel/vmm.h>
+#include <kernel/timer.h>
+#include <arch/cpu.h>
+
+static void timeout(context_t *, dpcarg_t arg) {
+	thread_t *thread = arg;
+	sched_wakeup(thread, 0);
+} 
+
+syscallret_t syscall_nanosleep(context_t *, timespec_t *utime, timespec_t *remaining) {
+	syscallret_t ret = {
+		.ret = -1
+	};
+
+	if ((void *)utime > USERSPACE_END || (void *)remaining > USERSPACE_END) {
+		ret.errno = EFAULT;
+		return ret;
+	}
+
+	timespec_t time = *utime;
+
+	if (time.ns > 999999999 || time.ns < 0) {
+		ret.errno = EINVAL;
+		return ret;
+	}
+
+	timerentry_t sleepentry;
+	sched_preparesleep(true);
+
+	sched_targetcpu(_cpu());
+	timer_insert(_cpu()->timer, &sleepentry, timeout, _cpu()->thread, time.s * 1000000 + time.ns / 1000, false);
+
+	ret.errno = sched_yield();
+
+	if (ret.errno) {
+		// XXX interruptible wait might break things
+		timer_remove(_cpu()->timer, &sleepentry);
+	}
+
+	sched_targetcpu(NULL);
+
+	ret.ret = 0;
+	return ret;
+}