cd9660_vfsops.c

早期freebsd实现

/*-
 * Copyright (c) 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley
 * by Pace Willisson ([e-mail]).  The Rock Ridge Extension
 * Support code is derived from software contributed to Berkeley
 * by Atsushi Murai ([e-mail]).
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *	@(#)cd9660_vfsops.c	8.3 (Berkeley) 1/31/94
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <miscfs/specfs/specdev.h>
#include <sys/mount.h>
#include <sys/buf.h>
#include <sys/file.h>
#include <sys/dkbad.h>
#include <sys/disklabel.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/malloc.h>

#include <isofs/cd9660/iso.h>
#include <isofs/cd9660/cd9660_node.h>

extern int enodev ();

struct vfsops cd9660_vfsops = {
	cd9660_mount,
	cd9660_start,
	cd9660_unmount,
	cd9660_root,
	cd9660_quotactl,
	cd9660_statfs,
	cd9660_sync,
	cd9660_vget,
	cd9660_fhtovp,
	cd9660_vptofh,
	cd9660_init,
};

/*
 * Called by vfs_mountroot when iso is going to be mounted as root.
 *
 * Name is updated by mount(8) after booting.
 */
#define ROOTNAME	"root_device"

static iso_mountfs();

cd9660_mountroot()
{
	register struct mount *mp;
	extern struct vnode *rootvp;
	struct proc *p = curproc;	/* XXX */
	struct iso_mnt *imp;
	register struct fs *fs;
	u_int size;
	int error;
	struct iso_args args;
	
	/*
	 * Get vnodes for swapdev and rootdev.
	 */
	if (bdevvp(swapdev, &swapdev_vp) || bdevvp(rootdev, &rootvp))
		panic("cd9660_mountroot: can't setup bdevvp's");

	mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK);
	bzero((char *)mp, (u_long)sizeof(struct mount));
	mp->mnt_op = &cd9660_vfsops;
	mp->mnt_flag = MNT_RDONLY;
	args.flags = ISOFSMNT_ROOT;
	if (error = iso_mountfs(rootvp, mp, p, &args)) {
		free(mp, M_MOUNT);
		return (error);
	}
	if (error = vfs_lock(mp)) {
		(void)cd9660_unmount(mp, 0, p);
		free(mp, M_MOUNT);
		return (error);
	}
	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
	mp->mnt_flag |= MNT_ROOTFS;
	mp->mnt_vnodecovered = NULLVP;
	imp = VFSTOISOFS(mp);
	bzero(imp->im_fsmnt, sizeof(imp->im_fsmnt));
	imp->im_fsmnt[0] = '/';
	bcopy((caddr_t)imp->im_fsmnt, (caddr_t)mp->mnt_stat.f_mntonname,
	    MNAMELEN);
	(void) copystr(ROOTNAME, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
	    &size);
	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
	(void) cd9660_statfs(mp, &mp->mnt_stat, p);
	vfs_unlock(mp);
	return (0);
}

/*
 * Flag to allow forcible unmounting.
 */
int iso_doforce = 1;

/*
 * VFS Operations.
 *
 * mount system call
 */
cd9660_mount(mp, path, data, ndp, p)
	register struct mount *mp;
	char *path;
	caddr_t data;
	struct nameidata *ndp;
	struct proc *p;
{
	struct vnode *devvp;
	struct iso_args args;
	u_int size;
	int error;
	struct iso_mnt *imp;
	
	if (error = copyin(data, (caddr_t)&args, sizeof (struct iso_args)))
		return (error);
	
	if ((mp->mnt_flag & MNT_RDONLY) == 0)
		return (EROFS);
	
	/*
	 * If updating, check whether changing from read-only to
	 * read/write; if there is no device name, that's all we do.
	 */
	if (mp->mnt_flag & MNT_UPDATE) {
		imp = VFSTOISOFS(mp);
		if (args.fspec == 0)
			return (vfs_export(mp, &imp->im_export, &args.export));
	}
	/*
	 * Not an update, or updating the name: look up the name
	 * and verify that it refers to a sensible block device.
	 */
	NDINIT(ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.fspec, p);
	if (error = namei(ndp))
		return (error);
	devvp = ndp->ni_vp;

	if (devvp->v_type != VBLK) {
		vrele(devvp);
		return ENOTBLK;
	}
	if (major(devvp->v_rdev) >= nblkdev) {
		vrele(devvp);
		return ENXIO;
	}
	if ((mp->mnt_flag & MNT_UPDATE) == 0)
		error = iso_mountfs(devvp, mp, p, &args);
	else {
		if (devvp != imp->im_devvp)
			error = EINVAL;	/* needs translation */
		else
			vrele(devvp);
	}
	if (error) {
		vrele(devvp);
		return error;
	}
	imp = VFSTOISOFS(mp);
	(void) copyinstr(path, imp->im_fsmnt, sizeof(imp->im_fsmnt)-1, &size);
	bzero(imp->im_fsmnt + size, sizeof(imp->im_fsmnt) - size);
	bcopy((caddr_t)imp->im_fsmnt, (caddr_t)mp->mnt_stat.f_mntonname,
	    MNAMELEN);
	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
	    &size);
	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
	(void) cd9660_statfs(mp, &mp->mnt_stat, p);
	return 0;
}

/*
 * Common code for mount and mountroot
 */
static iso_mountfs(devvp, mp, p, argp)
	register struct vnode *devvp;
	struct mount *mp;
	struct proc *p;
	struct iso_args *argp;
{
	register struct iso_mnt *isomp = (struct iso_mnt *)0;
	struct buf *bp = NULL;
	dev_t dev = devvp->v_rdev;
	caddr_t base, space;
	int havepart = 0, blks;
	int error = EINVAL, i, size;
	int needclose = 0;
	int ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
	extern struct vnode *rootvp;
	int j;
	int iso_bsize;
	int iso_blknum;
	struct iso_volume_descriptor *vdp;
	struct iso_primary_descriptor *pri;
	struct iso_directory_record *rootp;
	int logical_block_size;
	
	if (!ronly)
		return EROFS;
	
	/*
	 * Disallow multiple mounts of the same device.
	 * Disallow mounting of a device that is currently in use
	 * (except for root, which might share swap device for miniroot).
	 * Flush out any old buffers remaining from a previous use.
	 */
	if (error = vfs_mountedon(devvp))
		return error;
	if (vcount(devvp) > 1 && devvp != rootvp)
		return EBUSY;
	if (error = vinvalbuf(devvp, V_SAVE, p->p_ucred, p, 0, 0))
		return (error);

	if (error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, p))
		return error;
	needclose = 1;
	
	/* This is the "logical sector size".  The standard says this
	 * should be 2048 or the physical sector size on the device,
	 * whichever is greater.  For now, we'll just use a constant.
	 */
	iso_bsize = ISO_DEFAULT_BLOCK_SIZE;
	
	for (iso_blknum = 16; iso_blknum < 100; iso_blknum++) {
		if (error = bread (devvp, btodb(iso_blknum * iso_bsize),
				   iso_bsize, NOCRED, &bp))
			goto out;
		
		vdp = (struct iso_volume_descriptor *)bp->b_un.b_addr;
		if (bcmp (vdp->id, ISO_STANDARD_ID, sizeof vdp->id) != 0) {
			error = EINVAL;
			goto out;
		}
		
		if (isonum_711 (vdp->type) == ISO_VD_END) {
			error = EINVAL;
			goto out;
		}
		
		if (isonum_711 (vdp->type) == ISO_VD_PRIMARY)
			break;
		brelse(bp);
	}
	
	if (isonum_711 (vdp->type) != ISO_VD_PRIMARY) {
		error = EINVAL;
		goto out;
	}
	
	pri = (struct iso_primary_descriptor *)vdp;
	
	logical_block_size = isonum_723 (pri->logical_block_size);
	
	if (logical_block_size < DEV_BSIZE || logical_block_size > MAXBSIZE
	    || (logical_block_size & (logical_block_size - 1)) != 0) {
		error = EINVAL;
		goto out;
	}
	
	rootp = (struct iso_directory_record *)pri->root_directory_record;
	
	isomp = malloc(sizeof *isomp, M_ISOFSMNT, M_WAITOK);
	bzero((caddr_t)isomp, sizeof *isomp);
	isomp->logical_block_size = logical_block_size;
	isomp->volume_space_size = isonum_733 (pri->volume_space_size);
	bcopy (rootp, isomp->root, sizeof isomp->root);
	isomp->root_extent = isonum_733 (rootp->extent);
	isomp->root_size = isonum_733 (rootp->size);
	
	isomp->im_bmask = logical_block_size - 1;
	isomp->im_bshift = 0;
	while ((1 << isomp->im_bshift) < isomp->logical_block_size)
		isomp->im_bshift++;
	
	bp->b_flags |= B_AGE;
	brelse(bp);
	bp = NULL;
	
	mp->mnt_data = (qaddr_t)isomp;
	mp->mnt_stat.f_fsid.val[0] = (long)dev;
	mp->mnt_stat.f_fsid.val[1] = MOUNT_CD9660;
	mp->mnt_maxsymlinklen = 0;
	mp->mnt_flag |= MNT_LOCAL;
	isomp->im_mountp = mp;
	isomp->im_dev = dev;
	isomp->im_devvp = devvp;
	
	devvp->v_specflags |= SI_MOUNTEDON;
	
	/* Check the Rock Ridge Extention support */
	if (!(argp->flags & ISOFSMNT_NORRIP)) {
		if (error = bread (isomp->im_devvp,
				   (isomp->root_extent + isonum_711(rootp->ext_attr_length))
				   * isomp->logical_block_size / DEV_BSIZE,
				   isomp->logical_block_size,NOCRED,&bp))
		    goto out;
		
		rootp = (struct iso_directory_record *)bp->b_un.b_addr;
		
		if ((isomp->rr_skip = cd9660_rrip_offset(rootp,isomp)) < 0) {
		    argp->flags  |= ISOFSMNT_NORRIP;
		} else {