main.c

微内核软实时操作系统

/*
 * Copyright (c) 2005-2007, Kohsuke Ohtani
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the author nor the names of any co-contributors 
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * main.c - File system server
 */

/*
 * All file systems work as a sub-modules under VFS (Virtual File System).
 * The routines in this file have the responsible to the following jobs.
 *
 *  - Interpret the IPC message and pass the request into VFS routines.
 *  - Validate the some of passed arguments in the message.
 *  - Mapping of the task ID and cwd/file pointers.
 *
 * Note: All path string is translated to the full path before passing
 * it to the sys_* routines.
 */

#include <prex/prex.h>
#include <server/fs.h>

#include <sys/list.h>
#include <sys/stat.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/file.h>
#include <sys/syslog.h>

#include <limits.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>

#include "vfs.h"

#if NR_FS_THREADS > 1
extern int __isthreaded;	/* thread option in libc */
#endif

/*
 * Message mapping
 */
struct msg_map {
	int code;
	int (*func)();
};

/* Object for file service */
static object_t fs_obj;


static int fs_mount(tcb_t tcb, struct mount_msg *msg)
{
	cap_t cap;
	int err;

	/* Check mount capability. */
	if (task_getcap(msg->hdr.task, &cap))
		return EINVAL;
	if ((cap & CAP_FS_MOUNT) == 0)
		return EPERM;

	err = sys_mount(msg->dev, msg->dir, msg->fs, msg->flags,
			(void *)msg->data);
#ifdef DEBUG
	if (err)
		syslog(LOG_INFO, "fs: mount failed! fs=%s\n", msg->fs);
#endif
	return err;
}

static int fs_umount(tcb_t tcb, struct path_msg *msg)
{
	cap_t cap;

	/* Check mount capability. */
	if (task_getcap(msg->hdr.task, &cap))
		return EINVAL;
	if ((cap & CAP_FS_MOUNT) == 0)
		return EPERM;
	return sys_umount(msg->path);
}

static int fs_sync(tcb_t tcb, struct msg *msg)
{
	return sys_sync();
}

static int fs_open(tcb_t tcb, struct open_msg *msg)
{
	char path[PATH_MAX];
	file_t fp;
	int fd, err;

	/* Find empty slot for file descriptor */
	for (fd = 0; fd < OPEN_MAX; fd++)
		if (tcb->file[fd] == NULL)
			break;
	if (fd == OPEN_MAX)
		return EMFILE;
	if ((err = tcb_conv(tcb, msg->path, path)) != 0)
		return err;
	if ((err = sys_open(path, msg->flags, msg->mode, &fp)) != 0)
		return err;
	tcb->file[fd] = fp;
	tcb->nr_open++;
	msg->fd = fd;
	return 0;
}

static int fs_close(tcb_t tcb, struct msg *msg)
{
	file_t fp;
	int fd, err;

	fd = msg->data[0];
	if (fd >= OPEN_MAX)
		return EBADF;

	fp = tcb->file[fd];
	if (!fp)
		return EBADF;

	if ((err = sys_close(fp)) != 0)
		return err;

	tcb->file[fd] = NULL;
	tcb->nr_open--;
	return 0;
}

static int fs_mknod(tcb_t tcb, struct open_msg *msg)
{
	char path[PATH_MAX];
	int err;

	if ((err = tcb_conv(tcb, msg->path, path)) != 0)
		return err;
	return sys_mknod(path, msg->mode);
}

static int fs_lseek(tcb_t tcb, struct msg *msg)
{
	file_t fp;
	off_t offset, org;
	int err, type;

	if ((fp = tcb_getfp(tcb, msg->data[0])) == NULL)
		return EBADF;
	offset = (off_t)msg->data[1];
	type = msg->data[2];
	err = sys_lseek(fp, offset, type, &org);
	msg->data[0] = (int)org;
	return err;
}

static int fs_read(tcb_t tcb, struct io_msg *msg)
{
	file_t fp;
	void *buf;
	size_t size, bytes;
	int err;

	if ((fp = tcb_getfp(tcb, msg->fd)) == NULL)
		return EBADF;
	size = msg->size;
	if ((err = vm_map(msg->hdr.task, msg->buf, size, &buf)) != 0)
		return EFAULT;
	err = sys_read(fp, buf, size, &bytes);
	msg->size = bytes;
	vm_free(task_self(), buf);
	return err;
}

static int fs_write(tcb_t tcb, struct io_msg *msg)
{
	file_t fp;
	void *buf;
	size_t size, bytes;
	int err;

	if ((fp = tcb_getfp(tcb, msg->fd)) == NULL)
		return EBADF;
	size = msg->size;
	if ((err = vm_map(msg->hdr.task, msg->buf, size, &buf)) != 0)
		return EFAULT;
	err = sys_write(fp, buf, size, &bytes);
	msg->size = bytes;
	vm_free(task_self(), buf);
	return err;
}

static int fs_ioctl(tcb_t tcb, struct msg *msg)
{
	/* XXX */
	return 0;
}

static int fs_fsync(tcb_t tcb, struct msg *msg)
{
	file_t fp;

	if ((fp = tcb_getfp(tcb, msg->data[0])) == NULL)
		return EBADF;
	return sys_fsync(fp);
}

static int fs_fstat(tcb_t tcb, struct stat_msg *msg)
{
	file_t fp;
	struct stat *st;

	if ((fp = tcb_getfp(tcb, msg->fd)) == NULL)
		return EBADF;
	st = &msg->st;
	return sys_fstat(fp, st);
}

static int fs_opendir(tcb_t tcb, struct open_msg *msg)
{
	char path[PATH_MAX];
	file_t fp;
	int fd, err;

	/* Find empty slot for file structure */
	for (fd = 0; fd < OPEN_MAX; fd++)
		if (tcb->file[fd] == NULL)
			break;
	if (fd == OPEN_MAX)
		return EMFILE;

	/* Get the mounted file system and node */
	if ((err = tcb_conv(tcb, msg->path, path)) != 0)
		return err;
	if ((err = sys_opendir(path, &fp)) != 0)
		return err;
	tcb->file[fd] = fp;
	msg->fd = fd;
	return 0;
}

static int fs_closedir(tcb_t tcb, struct msg *msg)
{
	file_t fp;
	int fd, err;

	fd = msg->data[0];
	if (fd >= OPEN_MAX)
		return EBADF;
	fp = tcb->file[fd];
	if (fp == NULL)
		return EBADF;
	if ((err = sys_closedir(fp)) != 0)
		return err;
	tcb->file[fd] = NULL;
	return 0;
}

static int fs_readdir(tcb_t tcb, struct dir_msg *msg)
{
	file_t fp;

	if ((fp = tcb_getfp(tcb, msg->fd)) == NULL)
		return EBADF;
	return sys_readdir(fp, &msg->dirent);
}

static int fs_rewinddir(tcb_t tcb, struct msg *msg)
{
	file_t fp;

	if ((fp = tcb_getfp(tcb, msg->data[0])) == NULL)
		return EBADF;
	return sys_rewinddir(fp);
}

static int fs_seekdir(tcb_t tcb, struct msg *msg)
{
	file_t fp;
	long loc;

	if ((fp = tcb_getfp(tcb, msg->data[0])) == NULL)
		return EBADF;
	loc = msg->data[1];
	return sys_seekdir(fp, loc);
}

static int fs_telldir(tcb_t tcb, struct msg *msg)
{
	file_t fp;
	long loc;
	int err;

	if ((fp = tcb_getfp(tcb, msg->data[0])) == NULL)
		return EBADF;
	loc = msg->data[1];
	if ((err = sys_telldir(fp, &loc)) != 0)
		return err;
	msg->data[0] = loc;
	return 0;
}

static int fs_mkdir(tcb_t tcb, struct open_msg *msg)
{
	char path[PATH_MAX];
	int err;

	if ((err = tcb_conv(tcb, msg->path, path)) != 0)
		return err;
	return sys_mkdir(path, msg->mode);
}

static int fs_rmdir(tcb_t tcb, struct path_msg *msg)
{
	char path[PATH_MAX];
	int err;

	if (msg->path == NULL)
		return ENOENT;
	if ((err = tcb_conv(tcb, msg->path, path)) != 0)
		return err;
	return sys_rmdir(path);
}

static int fs_rename(tcb_t tcb, struct path_msg *msg)
{
	char src[PATH_MAX];
	char dest[PATH_MAX];
	int err;

	if (msg->path == NULL || msg->path2 == NULL)
		return ENOENT;
	if ((err = tcb_conv(tcb, msg->path, src)) != 0)
		return err;
	if ((err = tcb_conv(tcb, msg->path2, dest)) != 0)
		return err;
	return sys_rename(src, dest);
}

static int fs_chdir(tcb_t tcb, struct path_msg *msg)
{
	char path[PATH_MAX];
	file_t fp;
	int err;

	if (msg->path == NULL)
		return ENOENT;
	if ((err = tcb_conv(tcb, msg->path, path)) != 0)
		return err;
	/* Check if directory exits */
	if ((err = sys_opendir(path, &fp)) != 0)
		return err;
	if (tcb->cwd_fp)
		sys_closedir(tcb->cwd_fp);
	tcb->cwd_fp = fp;
	strcpy(tcb->cwd, path);
	return 0;
}

static int fs_link(tcb_t tcb, struct msg *msg)
{
	/* XXX */
	return EPERM;
}