/* 
 * 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>
#include <metalsvm/string.h>
#include <metalsvm/errno.h>

static int sys_write(int fd, 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 = -EINVAL;
	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_read: {
			int fd = va_arg(vl, int);
			const char* buf = va_arg(vl, const char*);
 			size_t len = va_arg(vl, size_t);
			read_fs(per_core(current_task)->fildes_table[fd].node, (uint8_t*)buf, len, per_core(current_task)->fildes_table[fd].offset);
			kprintf("Dateiinhalt:%i\n", len);
			sys_write(fd, buf, len);
			kprintf("\n");
			ret = 8;
			break;
		}
	case __NR_write: {
			int fd = va_arg(vl, int);
			const char* buf = va_arg(vl, const char*);
			size_t len = va_arg(vl, size_t);
			ret = write_fs(per_core(current_task)->fildes_table[fd].node, (uint8_t*)buf, len, per_core(current_task)->fildes_table[fd].offset);
			break;
		}
	case __NR_open: {
			const char* file = va_arg(vl, const char*);
			int flags = va_arg(vl, int);
			int mode = va_arg(vl, int);
			int fd = 0;
			for (fd = 0; fd < MAX_FILDES; fd++) {
				if (per_core(current_task)->fildes_table[fd].node == NULL) {
					per_core(current_task)->fildes_table[fd].node = findnode_fs((char*) file);
					ret = fd;
					break;
				} 
			}
			if (fd >= MAX_FILDES) {
				kprintf("Unable to create filedescriptor");
				ret = -EINVAL;
			}   
			break;
		}
	case __NR_close: {
			int fd = va_arg(vl, int);
			close_fs(per_core(current_task)->fildes_table[fd].node);
			per_core(current_task)->fildes_table[fd].node = NULL;
			per_core(current_task)->fildes_table[fd].offset = 0;
			ret = 0;
			break;
		}
	case __NR_getpid:
		ret = per_core(current_task)->id;
		break;
	case __NR_fork:
		ret = sys_fork();
		break;
	case __NR_wait: {
			int32_t* status = va_arg(vl, int32_t*);
		
			ret = wait(status);
			break;
		}
	case __NR_execve: {
			const char* name = va_arg(vl, const char*);
			char** argv = va_arg(vl, char**);
			char** env = va_arg(vl, char**);

			ret = sys_execve(name, argv, env);
			break;
		}
	default:
		kputs("invalid system call\n");
		ret = -ENOSYS;
		break;
	};

	va_end(vl);

	return ret;
}