/* 
 * Copyright 2010 Stefan Lankes, Chair for Operating Systems,
 *                               RWTH Aachen University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This file is part of MetalSVM.
 */

#include <metalsvm/stdarg.h>
#include <metalsvm/stdio.h>
#include <metalsvm/syscall.h>
#include <metalsvm/tasks.h>

static int sys_write(int fildes, const char *buf, size_t len)
{
	int i;

	if (BUILTIN_EXPECT(!buf, 0))
		return -1;

	for (i = 0; i<len; i++, buf++) {
		kputchar(*buf);
	}
        
	return len;
}

int syscall_handler(uint32_t sys_nr, ...)
{
	int ret = -1;
	va_list vl;

	va_start(vl, sys_nr);

	switch(sys_nr) 
	{
	case __NR_exit:
		sys_exit(va_arg(vl, uint32_t));
		ret = 0;
		break;
	case __NR_write: {
			int fildes = va_arg(vl, int);
			const char* buf = va_arg(vl, const char*);
			size_t len = va_arg(vl, size_t);
		
			ret = sys_write(fildes, buf, len);
			break;
		}
	case __NR_open:
		ret = 1;
		break;
	case __NR_close:
		ret = 0;
		break;
	case __NR_getpid:
		ret = current_task->id;
		break;
	case __NR_fstat:
	default:
		kputs("invalid system call\n");
		ret = -1;
		break;
	};

	va_end(vl);

	return ret;
}