metalsvm/kernel/syscall.c

/* 
 * 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>
#include <metalsvm/spinlock.h>
#include <metalsvm/time.h>


static int sys_write(int fd, const char *buf, size_t len)
{
	unsigned int wrotebytes;
	if (per_core(current_task)->fildes_table[fd].flags & O_APPEND) {
		per_core(current_task)->fildes_table[fd].offset = per_core(current_task)->fildes_table[fd].node->block_size;
	}

	wrotebytes = write_fs(per_core(current_task)->fildes_table[fd].node, (uint8_t*)buf, len, per_core(current_task)->fildes_table[fd].offset);
	//kprintf("writing into filesystem -- fd:%i, Filelength:%i, Writtenbytes: %i, Bufferlength: %s \n", fd, len, wrotebytes, buf);
	per_core(current_task)->fildes_table[fd].offset += wrotebytes;

	return wrotebytes;
}

static int sys_open(const char* file, int flags, int mode)
{
	int fd;
	if (!findnode_fs((char*) file)) {
		if (flags & O_CREAT) {
			//create file, not implemented yet
		}
		return -EINVAL;
	} else {
		if ((flags & O_CREAT) && (flags & O_EXCL));
			return -EINVAL;
	}

	for (fd = 3; fd < NR_OPEN; fd++) {
		if (per_core(current_task)->fildes_table[fd].node == NULL) {
			per_core(current_task)->fildes_table[fd].node = findnode_fs((char*) file);
			per_core(current_task)->fildes_table[fd].mode = mode;
			per_core(current_task)->fildes_table[fd].flags = flags;
		} 
 	}
	if (fd >= NR_OPEN) {
		kprintf("Unable to create filedescriptor");
		return -EINVAL;
	}   
	
	return fd;

}

static int sys_close(int fd)
{
	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;
	return 0;

}

static int sys_read(int fd, const char *buf, size_t len)
{
	unsigned int readbytes;
	readbytes = read_fs(
			per_core(current_task)->fildes_table[fd].node, 
			(uint8_t*)buf, len, 
			per_core(current_task)->fildes_table[fd].offset);
	per_core(current_task)->fildes_table[fd].offset += readbytes;
	/*kprintf("fd:%i, Filelength:%i, Bufferlength: %s X: %i\n", fd, len, buf, readbytes); */
	/* Beware: still reading above file limit! */
	return readbytes; 
}
 
static int sys_lseek(int fd, off_t pos, int origin)
{
	int ret = -EINVAL;

	if (BUILTIN_EXPECT(per_core(current_task)->fildes_table[fd].node->type != FS_FILE
			&& per_core(current_task)->fildes_table[fd].node->type != FS_CHARDEVICE, 0));
		return -EINVAL;

	switch(origin) 
	{	
	case SEEK_SET: {	/* set file offset to offset */
			per_core(current_task)->fildes_table[fd].offset = pos;
			ret = 0;
			break;
		}
	case SEEK_CUR: {	/* set file offset to current plus offset */
			ret = pos + per_core(current_task)->fildes_table[fd].offset;
			break;
		}
	case SEEK_END: {	/* set file offset to EOF plus offset */
			per_core(current_task)->fildes_table[fd].offset = pos + per_core(current_task)->fildes_table[fd].node->block_size;
			ret = 0;
			break;
		}
	default:
		ret = -EINVAL;
		break;
	}
	return ret;
}

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();

	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 fd = va_arg(vl, int);
			const char* buf = va_arg(vl, const char*);
			size_t len = va_arg(vl, size_t);
			ret = sys_write(fd, buf, len);
			break;
		}
	case __NR_open: {
			const char* file = va_arg(vl, const char*);
			int flags = va_arg(vl, int);
			int mode = va_arg(vl, int);
			ret = sys_open(file, flags, mode);
			break;
		}
	case __NR_close: {
			int fd = va_arg(vl, int);
			ret = sys_close(fd);
 			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);
			ret = sys_read(fd, buf, len);
			break;
		}
	case __NR_lseek: {
			int fd = va_arg(vl, int);
			off_t pos = va_arg(vl, off_t);
 			int origin = va_arg(vl, int);
			ret = sys_lseek(fd, pos, origin);
			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;
		}
	default:
		kputs("invalid system call\n");
		ret = -ENOSYS;
		break;
	};

	va_end(vl);

	return ret;
}