/* 
 * 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/errno.h>
#include <metalsvm/spinlock.h>
#include <metalsvm/time.h>
#include <lwip/opt.h>

#if defined(CONFIG_LWIP) && LWIP_SOCKET
#include <lwip/mem.h>
#include <lwip/raw.h>
#include <lwip/icmp.h>
#include <lwip/netif.h>
#include <lwip/sys.h>
#include <lwip/timers.h>
#include <lwip/inet_chksum.h>
#include <lwip/ip.h>
#include <lwip/sockets.h>
#include <lwip/inet.h>
#include <lwip/err.h>

/* 
 * We set the a bit LWIP_FD_BIT to determine,
 * if the descriptor belongs to LwIP or MetalSVM.
 */
#define LWIP_FD_BIT		(1 << 28)
#endif

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;
}

static int sys_sbrk(int incr)
{
	task_t* task = per_core(current_task);
	vma_t* tmp = NULL;
	int ret;

	spinlock_lock(&task->vma_lock);

	tmp = task->vma_list;
        while(tmp && !((task->end_heap >= tmp->start) && (task->end_heap <= tmp->end)))
		tmp = tmp->next;

	ret = (int) task->end_heap;
	task->end_heap += incr;
	if (task->end_heap < task->start_heap)
		task->end_heap = task->start_heap;
	
	// resize virtual memory area
	if (tmp && (tmp->end <= task->end_heap))
		tmp->end = task->end_heap;

	spinlock_unlock(&task->vma_lock);

	return ret;
}

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

	check_workqueues_rem_irq();

	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);
		
#if defined(CONFIG_LWIP) && LWIP_SOCKET
			if (fildes & LWIP_FD_BIT) {
				ret = lwip_write(fildes & ~LWIP_FD_BIT, buf, len);
				if (ret < 0)
					ret = -errno;
			} else  ret = sys_write(fildes, buf, len);
#else
			ret = sys_write(fildes, buf, len);
#endif
			break;
		}
	case __NR_open:
		ret = 1;
		break;
	case __NR_close: {
#if defined(CONFIG_LWIP) && LWIP_SOCKET
		int s = va_arg(vl, int);
		if (s & LWIP_FD_BIT) {
			ret = lwip_close(s & ~LWIP_FD_BIT);
			if (ret < 0)
				ret = -errno;
		} else ret = 0;
#else
		ret = 0;
#endif
		break;
	}
	case __NR_sbrk: {
			int incr = va_arg(vl, int);

			ret = sys_sbrk(incr);
			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;
		}
	case __NR_times: {
			struct tms* buffer = va_arg(vl, struct tms*);
			clock_t* clock = va_arg(vl, clock_t*);

			ret = sys_times(buffer, clock);
			break;
		}
#if defined(CONFIG_LWIP) && LWIP_SOCKET
	case __NR_read: {
		int s = va_arg(vl, int);
		void* mem = va_arg(vl, void*);
		size_t len = va_arg(vl, size_t);

		if (!(s & LWIP_FD_BIT)) {
			ret = -ENOTSOCK;
			break;
		}

		ret = lwip_read(s & ~LWIP_FD_BIT, mem, len);
		if (ret < 0)
			ret = -errno;
		break;
	}
	case __NR_closesocket: {
		int s = va_arg(vl, int);

		if (BUILTIN_EXPECT(!(s & LWIP_FD_BIT), 0)) {
			ret = -ENOTSOCK;
			break;
		}

		ret = lwip_close(s & ~LWIP_FD_BIT);
		if (ret < 0)
			ret = -errno;
		break;
	}
	case __NR_socket: {
		int domain = va_arg(vl, int);
		int type = va_arg(vl, int);
		int protocol = va_arg(vl, int);

		ret = lwip_socket(domain, type, protocol);
		if (ret >= 0)
			ret |= LWIP_FD_BIT;
		else
			ret = -errno;
		break;
	}
	case __NR_connect: {
		int s = va_arg(vl, int);
		const struct sockaddr* name = va_arg(vl, const struct sockaddr*);
		socklen_t namelen = va_arg(vl, socklen_t);

		if (BUILTIN_EXPECT(!(s & LWIP_FD_BIT), 0)) {
			ret = -ENOTSOCK;
			break;
		}

		ret = lwip_connect(s & ~LWIP_FD_BIT, name, namelen);
		if (ret < 0)
			ret = -errno;
		break;
	}
	case __NR_bind: {
		int s = va_arg(vl, int);
		const struct sockaddr* name = va_arg(vl, const struct sockaddr*);
		socklen_t namelen = va_arg(vl, socklen_t);

		if (BUILTIN_EXPECT(!(s & LWIP_FD_BIT), 0)) {
			ret = -ENOTSOCK;
			break;
		}

		ret = lwip_bind(s & ~LWIP_FD_BIT, name, namelen);
		if (ret < 0)
			ret = -errno;
		break;
	}
	case __NR_listen:{
		int s = va_arg(vl, int);
		int backlog = va_arg(vl, int);

		if (BUILTIN_EXPECT(!(s & LWIP_FD_BIT), 0)) {
			ret = -ENOTSOCK;
			break;
		}

		ret = lwip_listen(s & ~LWIP_FD_BIT, backlog);
		if (ret < 0)
			ret = -errno;
		break;
	}
	case __NR_accept: {
		int s = va_arg(vl, int);
		struct sockaddr* addr = va_arg(vl, struct sockaddr*);
		socklen_t* addrlen = va_arg(vl, socklen_t*);

		if (BUILTIN_EXPECT(!(s & LWIP_FD_BIT), 0)) {
			ret = -ENOTSOCK;
			break;
		}

		ret = lwip_accept(s & ~LWIP_FD_BIT, addr, addrlen);
		if (ret >= 0)
			ret |= LWIP_FD_BIT;
		else
			ret = -errno;
		break;
	}
#endif
	default:
		kputs("invalid system call\n");
		ret = -ENOSYS;
		break;
	};

	va_end(vl);

	return ret;
}