2 * Copyright (c) 1988 University of Utah.
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * from: Utah Hdr: vn.c 1.13 94/04/02
40 * from: @(#)vn.c 8.6 (Berkeley) 4/1/94
41 * $FreeBSD: src/sys/dev/vn/vn.c,v 1.105.2.4 2001/11/18 07:11:00 dillon Exp $
47 * Block/character interface to a vnode. Allows one to treat a file
48 * as a disk (e.g. build a filesystem in it, mount it, etc.).
50 * NOTE 1: There is a security issue involved with this driver.
51 * Once mounted all access to the contents of the "mapped" file via
52 * the special file is controlled by the permissions on the special
53 * file, the protection of the mapped file is ignored (effectively,
54 * by using root credentials in all transactions).
56 * NOTE 2: Doesn't interact with leases, should it?
60 #include <sys/param.h>
61 #include <sys/systm.h>
62 #include <sys/kernel.h>
65 #include <sys/nlookup.h>
67 #include <sys/malloc.h>
68 #include <sys/mount.h>
69 #include <sys/vnode.h>
70 #include <sys/fcntl.h>
72 #include <sys/diskslice.h>
75 #include <sys/module.h>
76 #include <sys/vnioctl.h>
79 #include <vm/vm_object.h>
80 #include <vm/vm_page.h>
81 #include <vm/vm_pager.h>
82 #include <vm/vm_pageout.h>
83 #include <vm/swap_pager.h>
84 #include <vm/vm_extern.h>
85 #include <vm/vm_zone.h>
86 #include <sys/devfs.h>
88 static d_ioctl_t vnioctl;
89 static d_open_t vnopen;
90 static d_close_t vnclose;
91 static d_psize_t vnsize;
92 static d_strategy_t vnstrategy;
93 static d_clone_t vnclone;
95 DEVFS_DECLARE_CLONE_BITMAP(vn);
98 #define VN_PREALLOCATED_UNITS 4
100 #define VN_PREALLOCATED_UNITS NVN
103 #define VN_BSIZE_BEST 8192
107 * D_DISK we want to look like a disk
108 * D_CANFREE We support BUF_CMD_FREEBLKS
111 static struct dev_ops vn_ops = {
112 { "vn", 0, D_DISK | D_CANFREE },
116 .d_write = physwrite,
118 .d_strategy = vnstrategy,
124 int sc_flags; /* flags */
125 u_int64_t sc_size; /* size of vn, sc_secsize scale */
126 int sc_secsize; /* sector size */
128 struct vnode *sc_vp; /* vnode if not NULL */
129 vm_object_t sc_object; /* backing object if not NULL */
130 struct ucred *sc_cred; /* credentials */
131 int sc_maxactive; /* max # of active requests */
132 struct buf sc_tab; /* transfer queue */
133 u_long sc_options; /* options */
134 cdev_t sc_devlist; /* devices that refer to this unit */
135 SLIST_ENTRY(vn_softc) sc_list;
138 static SLIST_HEAD(, vn_softc) vn_list;
141 #define VNF_INITED 0x01
142 #define VNF_READONLY 0x02
144 static u_long vn_options;
146 #define IFOPT(vn,opt) if (((vn)->sc_options|vn_options) & (opt))
147 #define TESTOPT(vn,opt) (((vn)->sc_options|vn_options) & (opt))
149 static int vnsetcred (struct vn_softc *vn, struct ucred *cred);
150 static void vnclear (struct vn_softc *vn);
151 static int vnget (cdev_t dev, struct vn_softc *vn , struct vn_user *vnu);
152 static int vn_modevent (module_t, int, void *);
153 static int vniocattach_file (struct vn_softc *, struct vn_ioctl *, cdev_t dev, int flag, struct ucred *cred);
154 static int vniocattach_swap (struct vn_softc *, struct vn_ioctl *, cdev_t dev, int flag, struct ucred *cred);
155 static cdev_t vn_create(int unit, struct devfs_bitmap *bitmap);
158 vnclone(struct dev_clone_args *ap)
162 unit = devfs_clone_bitmap_get(&DEVFS_CLONE_BITMAP(vn), 0);
163 ap->a_dev = vn_create(unit, &DEVFS_CLONE_BITMAP(vn));
169 vnclose(struct dev_close_args *ap)
174 static struct vn_softc *
179 vn = kmalloc(sizeof *vn, M_DEVBUF, M_WAITOK | M_ZERO);
184 vninitvn(struct vn_softc *vn, cdev_t dev)
188 KKASSERT(vn != NULL);
189 KKASSERT(dev != NULL);
194 vn->sc_devlist = dev;
195 if (vn->sc_devlist->si_drv1 == NULL) {
196 reference_dev(vn->sc_devlist);
197 vn->sc_devlist->si_drv1 = vn;
198 vn->sc_devlist->si_drv2 = NULL;
200 if (vn->sc_devlist != dev) {
202 dev->si_drv2 = vn->sc_devlist;
203 vn->sc_devlist = dev;
206 SLIST_INSERT_HEAD(&vn_list, vn, sc_list);
210 * Called only when si_drv1 is NULL. Locate the associated vn node and
211 * attach the device to it.
213 static struct vn_softc *
220 SLIST_FOREACH(vn, &vn_list, sc_list) {
221 if (vn->sc_unit == unit) {
223 dev->si_drv2 = vn->sc_devlist;
224 vn->sc_devlist = dev;
230 KKASSERT(vn != NULL);
236 vnopen(struct dev_open_args *ap)
238 cdev_t dev = ap->a_head.a_dev;
242 * Locate preexisting device
245 if ((vn = dev->si_drv1) == NULL)
249 * Update si_bsize fields for device. This data will be overriden by
250 * the slice/parition code for vn accesses through partitions, and
251 * used directly if you open the 'whole disk' device.
253 * si_bsize_best must be reinitialized in case VN has been
254 * reconfigured, plus make it at least VN_BSIZE_BEST for efficiency.
256 dev->si_bsize_phys = vn->sc_secsize;
257 dev->si_bsize_best = vn->sc_secsize;
258 if (dev->si_bsize_best < VN_BSIZE_BEST)
259 dev->si_bsize_best = VN_BSIZE_BEST;
261 if ((ap->a_oflags & FWRITE) && (vn->sc_flags & VNF_READONLY))
265 kprintf("vnopen(%s, 0x%x, 0x%x)\n",
266 devtoname(dev), ap->a_oflags, ap->a_devtype);
274 * Run strategy routine for VN device. We use VOP_READ/VOP_WRITE calls
275 * for vnode-backed vn's, and the swap_pager_strategy() call for
276 * vm_object-backed vn's.
279 vnstrategy(struct dev_strategy_args *ap)
281 cdev_t dev = ap->a_head.a_dev;
282 struct bio *bio = ap->a_bio;
290 if ((vn = dev->si_drv1) == NULL)
296 kprintf("vnstrategy(%p): unit %d\n", bp, unit);
298 if ((vn->sc_flags & VNF_INITED) == 0) {
300 bp->b_flags |= B_ERROR;
305 bp->b_resid = bp->b_bcount;
308 * The vnode device is using disk/slice label support.
310 * The dscheck() function is called for validating the
311 * slices that exist ON the vnode device itself, and
312 * translate the "slice-relative" block number, again.
313 * dscheck() will call biodone() and return NULL if
314 * we are at EOF or beyond the device size.
320 * Use the translated nbio from this point on
322 if (vn->sc_vp && bp->b_cmd == BUF_CMD_FREEBLKS) {
324 * Freeblks is not handled for vnode-backed elements yet.
327 /* operation complete */
328 } else if (vn->sc_vp) {
332 * If an error occurs, we set B_ERROR but we do not set
333 * B_INVAL because (for a write anyway), the buffer is
339 bzero(&auio, sizeof(auio));
341 aiov.iov_base = bp->b_data;
342 aiov.iov_len = bp->b_bcount;
343 auio.uio_iov = &aiov;
345 auio.uio_offset = nbio->bio_offset;
346 auio.uio_segflg = UIO_SYSSPACE;
347 if (bp->b_cmd == BUF_CMD_READ)
348 auio.uio_rw = UIO_READ;
350 auio.uio_rw = UIO_WRITE;
351 auio.uio_resid = bp->b_bcount;
352 auio.uio_td = curthread;
355 * Don't use IO_DIRECT here, it really gets in the way
356 * due to typical blocksize differences between the
357 * fs backing the VN device and whatever is running on
360 if (bp->b_cmd == BUF_CMD_READ) {
361 vn_lock(vn->sc_vp, LK_SHARED | LK_RETRY);
362 error = VOP_READ(vn->sc_vp, &auio, IO_RECURSE,
365 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY);
366 error = VOP_WRITE(vn->sc_vp, &auio, IO_RECURSE,
369 vn_unlock(vn->sc_vp);
370 bp->b_resid = auio.uio_resid;
373 bp->b_flags |= B_ERROR;
375 /* operation complete */
376 } else if (vn->sc_object) {
378 * OBJT_SWAP I/O (handles read, write, freebuf)
380 * We have nothing to do if freeing blocks on a reserved
381 * swap area, othrewise execute the op.
383 if (bp->b_cmd == BUF_CMD_FREEBLKS && TESTOPT(vn, VN_RESERVE)) {
385 /* operation complete */
387 swap_pager_strategy(vn->sc_object, nbio);
392 bp->b_resid = bp->b_bcount;
393 bp->b_flags |= B_ERROR | B_INVAL;
394 bp->b_error = EINVAL;
395 /* operation complete */
403 vnioctl(struct dev_ioctl_args *ap)
405 cdev_t dev = ap->a_head.a_dev;
407 struct vn_ioctl *vio;
412 IFOPT(vn,VN_FOLLOW) {
413 kprintf("vnioctl(%s, 0x%lx, %p, 0x%x): unit %d\n",
414 devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag,
430 if (dkslice(dev) != WHOLE_DISK_SLICE ||
431 dkpart(dev) != WHOLE_SLICE_PART)
437 error = priv_check_cred(ap->a_cred, PRIV_ROOT, 0);
441 vio = (struct vn_ioctl *)ap->a_data;
442 f = (u_long*)ap->a_data;
446 if (vn->sc_flags & VNF_INITED)
449 if (vio->vn_file == NULL)
450 error = vniocattach_swap(vn, vio, dev, ap->a_fflag, ap->a_cred);
452 error = vniocattach_file(vn, vio, dev, ap->a_fflag, ap->a_cred);
456 if ((vn->sc_flags & VNF_INITED) == 0)
459 * XXX handle i/o in progress. Return EBUSY, or wait, or
461 * XXX handle multiple opens of the device. Return EBUSY,
462 * or revoke the fd's.
463 * How are these problems handled for removable and failing
464 * hardware devices? (Hint: They are not)
466 if (count_dev(vn->sc_devlist) > 1)
471 kprintf("vnioctl: CLRed\n");
473 if (dkunit(dev) >= VN_PREALLOCATED_UNITS) {
474 devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(vn), dkunit(dev));
475 disk_destroy(&vn->sc_disk);
476 SLIST_REMOVE(&vn_list, vn, vn_softc, sc_list);
482 error = vnget(dev, vn, (struct vn_user *) ap->a_data);
496 vn->sc_options |= *f;
501 vn->sc_options &= ~(*f);
515 * Attach a file to a VN partition. Return the size in the vn_size
520 vniocattach_file(struct vn_softc *vn, struct vn_ioctl *vio, cdev_t dev,
521 int flag, struct ucred *cred)
524 struct nlookupdata nd;
527 struct disk_info info;
529 flags = FREAD|FWRITE;
530 error = nlookup_init(&nd, vio->vn_file,
531 UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
534 if ((error = vn_open(&nd, NULL, flags, 0)) != 0) {
535 if (error != EACCES && error != EPERM && error != EROFS)
539 error = nlookup_init(&nd, vio->vn_file, UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
542 if ((error = vn_open(&nd, NULL, flags, 0)) != 0)
546 if (vp->v_type != VREG ||
547 (error = VOP_GETATTR(vp, &vattr))) {
553 vn->sc_secsize = DEV_BSIZE;
555 nd.nl_open_vp = NULL;
558 * If the size is specified, override the file attributes. Note that
559 * the vn_size argument is in PAGE_SIZE sized blocks.
562 vn->sc_size = vio->vn_size * PAGE_SIZE / vn->sc_secsize;
564 vn->sc_size = vattr.va_size / vn->sc_secsize;
565 error = vnsetcred(vn, cred);
571 vn->sc_flags |= VNF_INITED;
573 vn->sc_flags |= VNF_READONLY;
576 * Set the disk info so that probing is triggered
578 bzero(&info, sizeof(struct disk_info));
579 info.d_media_blksize = vn->sc_secsize;
580 info.d_media_blocks = vn->sc_size;
582 * reserve mbr sector for backwards compatibility
583 * when no slices exist.
585 info.d_dsflags = DSO_COMPATMBR;
586 info.d_secpertrack = 32;
587 info.d_nheads = 64 / (vn->sc_secsize / DEV_BSIZE);
588 info.d_secpercyl = info.d_secpertrack * info.d_nheads;
589 info.d_ncylinders = vn->sc_size / info.d_secpercyl;
590 disk_setdiskinfo_sync(&vn->sc_disk, &info);
592 error = dev_dopen(dev, flag, S_IFCHR, cred);
597 kprintf("vnioctl: SET vp %p size %llx blks\n",
598 vn->sc_vp, (long long)vn->sc_size);
607 * Attach swap backing store to a VN partition of the size specified
612 vniocattach_swap(struct vn_softc *vn, struct vn_ioctl *vio, cdev_t dev,
613 int flag, struct ucred *cred)
616 struct disk_info info;
619 * Range check. Disallow negative sizes or any size less then the
620 * size of a page. Then round to a page.
623 if (vio->vn_size <= 0)
627 * Allocate an OBJT_SWAP object.
629 * sc_secsize is PAGE_SIZE'd
631 * vio->vn_size is in PAGE_SIZE'd chunks.
632 * sc_size must be in PAGE_SIZE'd chunks.
633 * Note the truncation.
636 vn->sc_secsize = PAGE_SIZE;
637 vn->sc_size = vio->vn_size;
638 vn->sc_object = swap_pager_alloc(NULL,
639 vn->sc_secsize * (off_t)vio->vn_size,
641 IFOPT(vn, VN_RESERVE) {
642 if (swap_pager_reserve(vn->sc_object, 0, vn->sc_size) < 0) {
643 vm_pager_deallocate(vn->sc_object);
644 vn->sc_object = NULL;
648 vn->sc_flags |= VNF_INITED;
650 error = vnsetcred(vn, cred);
653 * Set the disk info so that probing is triggered
655 bzero(&info, sizeof(struct disk_info));
656 info.d_media_blksize = vn->sc_secsize;
657 info.d_media_blocks = vn->sc_size;
659 * reserve mbr sector for backwards compatibility
660 * when no slices exist.
662 info.d_dsflags = DSO_COMPATMBR;
663 info.d_secpertrack = 32;
664 info.d_nheads = 64 / (vn->sc_secsize / DEV_BSIZE);
665 info.d_secpercyl = info.d_secpertrack * info.d_nheads;
666 info.d_ncylinders = vn->sc_size / info.d_secpercyl;
667 disk_setdiskinfo_sync(&vn->sc_disk, &info);
669 error = dev_dopen(dev, flag, S_IFCHR, cred);
672 IFOPT(vn, VN_FOLLOW) {
673 kprintf("vnioctl: SET vp %p size %llx\n",
674 vn->sc_vp, (long long)vn->sc_size);
683 * Duplicate the current processes' credentials. Since we are called only
684 * as the result of a SET ioctl and only root can do that, any future access
685 * to this "disk" is essentially as root. Note that credentials may change
686 * if some other uid can write directly to the mapped file (NFS).
689 vnsetcred(struct vn_softc *vn, struct ucred *cred)
695 * Set credits in our softc
700 vn->sc_cred = crdup(cred);
703 * Horrible kludge to establish credentials for NFS XXX.
710 tmpbuf = kmalloc(vn->sc_secsize, M_TEMP, M_WAITOK);
711 bzero(&auio, sizeof(auio));
713 aiov.iov_base = tmpbuf;
714 aiov.iov_len = vn->sc_secsize;
715 auio.uio_iov = &aiov;
718 auio.uio_rw = UIO_READ;
719 auio.uio_segflg = UIO_SYSSPACE;
720 auio.uio_resid = aiov.iov_len;
721 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY);
722 error = VOP_READ(vn->sc_vp, &auio, 0, vn->sc_cred);
723 vn_unlock(vn->sc_vp);
724 kfree(tmpbuf, M_TEMP);
730 vnclear(struct vn_softc *vn)
733 kprintf("vnclear(%p): vp=%p\n", vn, vn->sc_vp);
734 vn->sc_flags &= ~VNF_INITED;
735 if (vn->sc_vp != NULL) {
737 (vn->sc_flags & VNF_READONLY) ? FREAD : (FREAD|FWRITE));
740 vn->sc_flags &= ~VNF_READONLY;
745 if (vn->sc_object != NULL) {
746 vm_pager_deallocate(vn->sc_object);
747 vn->sc_object = NULL;
750 disk_unprobe(&vn->sc_disk);
758 * populate a struct vn_user for the VNIOCGET ioctl.
759 * interface conventions defined in sys/sys/vnioctl.h.
763 vnget(cdev_t dev, struct vn_softc *vn, struct vn_user *vnu)
765 int error, found = 0;
766 char *freepath, *fullpath;
769 if (vnu->vnu_unit == -1) {
770 vnu->vnu_unit = dkunit(dev);
772 else if (vnu->vnu_unit < 0)
775 SLIST_FOREACH(vn, &vn_list, sc_list) {
777 if(vn->sc_unit != vnu->vnu_unit)
782 if (vn->sc_flags & VNF_INITED && vn->sc_vp != NULL) {
784 /* note: u_cred checked in vnioctl above */
785 error = VOP_GETATTR(vn->sc_vp, &vattr);
787 kprintf("vnget: VOP_GETATTR for %p failed\n",
792 error = vn_fullpath(curproc, vn->sc_vp,
793 &fullpath, &freepath, 0);
796 kprintf("vnget: unable to resolve vp %p\n",
801 strlcpy(vnu->vnu_file, fullpath,
802 sizeof(vnu->vnu_file));
803 kfree(freepath, M_TEMP);
804 vnu->vnu_dev = vattr.va_fsid;
805 vnu->vnu_ino = vattr.va_fileid;
808 else if (vn->sc_flags & VNF_INITED && vn->sc_object != NULL){
810 strlcpy(vnu->vnu_file, _VN_USER_SWAP,
811 sizeof(vnu->vnu_file));
812 vnu->vnu_size = vn->sc_size;
813 vnu->vnu_secsize = vn->sc_secsize;
817 bzero(vnu->vnu_file, sizeof(vnu->vnu_file));
832 vnsize(struct dev_psize_args *ap)
834 cdev_t dev = ap->a_head.a_dev;
840 if ((vn->sc_flags & VNF_INITED) == 0)
842 ap->a_result = (int64_t)vn->sc_size;
847 vn_create(int unit, struct devfs_bitmap *bitmap)
850 struct disk_info info;
854 dev = disk_create(unit, &vn->sc_disk, &vn_ops);
857 bzero(&info, sizeof(struct disk_info));
858 info.d_media_blksize = 512;
859 info.d_media_blocks = 0;
860 info.d_dsflags = DSO_MBRQUIET;
861 info.d_secpertrack = 32;
863 info.d_secpercyl = info.d_secpertrack * info.d_nheads;
864 info.d_ncylinders = 0;
865 disk_setdiskinfo_sync(&vn->sc_disk, &info);
868 devfs_clone_bitmap_set(bitmap, unit);
874 vn_modevent(module_t mod, int type, void *data)
877 static cdev_t dev = NULL;
882 dev = make_autoclone_dev(&vn_ops, &DEVFS_CLONE_BITMAP(vn), vnclone, UID_ROOT,
883 GID_OPERATOR, 0640, "vn");
885 for (i = 0; i < VN_PREALLOCATED_UNITS; i++) {
886 vn_create(i, &DEVFS_CLONE_BITMAP(vn));
890 destroy_autoclone_dev(dev, &DEVFS_CLONE_BITMAP(vn));
893 while ((vn = SLIST_FIRST(&vn_list)) != NULL) {
894 SLIST_REMOVE_HEAD(&vn_list, sc_list);
895 if (vn->sc_flags & VNF_INITED)
897 /* Cleanup all cdev_t's that refer to this unit */
898 disk_destroy(&vn->sc_disk);
899 while ((dev = vn->sc_devlist) != NULL) {
900 vn->sc_devlist = dev->si_drv2;
901 dev->si_drv1 = dev->si_drv2 = NULL;
906 dev_ops_remove_all(&vn_ops);
914 DEV_MODULE(vn, vn_modevent, 0);