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 MALLOC_DEFINE(M_VN, "vn_softc", "vn driver structures");
96 DEVFS_DECLARE_CLONE_BITMAP(vn);
99 #define VN_PREALLOCATED_UNITS 4
101 #define VN_PREALLOCATED_UNITS NVN
104 #define VN_BSIZE_BEST 8192
108 * D_DISK we want to look like a disk
109 * D_CANFREE We support BUF_CMD_FREEBLKS
112 static struct dev_ops vn_ops = {
113 { "vn", 0, D_DISK | D_CANFREE },
117 .d_write = physwrite,
119 .d_strategy = vnstrategy,
125 int sc_flags; /* flags */
126 u_int64_t sc_size; /* size of vn, sc_secsize scale */
127 int sc_secsize; /* sector size */
129 struct vnode *sc_vp; /* vnode if not NULL */
130 vm_object_t sc_object; /* backing object if not NULL */
131 struct ucred *sc_cred; /* credentials */
132 int sc_maxactive; /* max # of active requests */
133 struct buf sc_tab; /* transfer queue */
134 u_long sc_options; /* options */
135 cdev_t sc_dev; /* devices that refer to this unit */
136 SLIST_ENTRY(vn_softc) sc_list;
139 static SLIST_HEAD(, vn_softc) vn_list;
142 #define VNF_INITED 0x01
143 #define VNF_READONLY 0x02
144 #define VNF_OPENED 0x10
145 #define VNF_DESTROY 0x20
147 static u_long vn_options;
149 #define IFOPT(vn,opt) if (((vn)->sc_options|vn_options) & (opt))
150 #define TESTOPT(vn,opt) (((vn)->sc_options|vn_options) & (opt))
152 static int vnsetcred (struct vn_softc *vn, struct ucred *cred);
153 static void vnclear (struct vn_softc *vn);
154 static int vnget (cdev_t dev, struct vn_softc *vn , struct vn_user *vnu);
155 static int vn_modevent (module_t, int, void *);
156 static int vniocattach_file (struct vn_softc *, struct vn_ioctl *, cdev_t dev, int flag, struct ucred *cred);
157 static int vniocattach_swap (struct vn_softc *, struct vn_ioctl *, cdev_t dev, int flag, struct ucred *cred);
158 static cdev_t vn_create(int unit, struct devfs_bitmap *bitmap, int clone);
161 vnclone(struct dev_clone_args *ap)
165 unit = devfs_clone_bitmap_get(&DEVFS_CLONE_BITMAP(vn), 0);
166 ap->a_dev = vn_create(unit, &DEVFS_CLONE_BITMAP(vn), 1);
172 vnclose(struct dev_close_args *ap)
174 cdev_t dev = ap->a_head.a_dev;
178 KKASSERT(vn != NULL);
180 vn->sc_flags &= ~VNF_OPENED;
182 /* The disk has been detached and can now be safely destroyed */
183 if (vn->sc_flags & VNF_DESTROY) {
184 KKASSERT(disk_getopencount(&vn->sc_disk) == 0);
185 disk_destroy(&vn->sc_disk);
186 devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(vn), dkunit(dev));
187 SLIST_REMOVE(&vn_list, vn, vn_softc, sc_list);
193 static struct vn_softc *
198 vn = kmalloc(sizeof *vn, M_VN, M_WAITOK | M_ZERO);
203 vninitvn(struct vn_softc *vn, cdev_t dev)
207 KKASSERT(vn != NULL);
208 KKASSERT(dev != NULL);
215 SLIST_INSERT_HEAD(&vn_list, vn, sc_list);
219 vnopen(struct dev_open_args *ap)
221 cdev_t dev = ap->a_head.a_dev;
225 * Locate preexisting device
229 KKASSERT(vn != NULL);
232 * Update si_bsize fields for device. This data will be overriden by
233 * the slice/parition code for vn accesses through partitions, and
234 * used directly if you open the 'whole disk' device.
236 * si_bsize_best must be reinitialized in case VN has been
237 * reconfigured, plus make it at least VN_BSIZE_BEST for efficiency.
239 dev->si_bsize_phys = vn->sc_secsize;
240 dev->si_bsize_best = vn->sc_secsize;
241 if (dev->si_bsize_best < VN_BSIZE_BEST)
242 dev->si_bsize_best = VN_BSIZE_BEST;
244 if ((ap->a_oflags & FWRITE) && (vn->sc_flags & VNF_READONLY))
248 kprintf("vnopen(%s, 0x%x, 0x%x)\n",
249 devtoname(dev), ap->a_oflags, ap->a_devtype);
251 vn->sc_flags |= VNF_OPENED;
258 * Run strategy routine for VN device. We use VOP_READ/VOP_WRITE calls
259 * for vnode-backed vn's, and the swap_pager_strategy() call for
260 * vm_object-backed vn's.
263 vnstrategy(struct dev_strategy_args *ap)
265 cdev_t dev = ap->a_head.a_dev;
266 struct bio *bio = ap->a_bio;
275 KKASSERT(vn != NULL);
280 kprintf("vnstrategy(%p): unit %d\n", bp, unit);
282 if ((vn->sc_flags & VNF_INITED) == 0) {
284 bp->b_flags |= B_ERROR;
289 bp->b_resid = bp->b_bcount;
292 * The vnode device is using disk/slice label support.
294 * The dscheck() function is called for validating the
295 * slices that exist ON the vnode device itself, and
296 * translate the "slice-relative" block number, again.
297 * dscheck() will call biodone() and return NULL if
298 * we are at EOF or beyond the device size.
304 * Use the translated nbio from this point on
306 if (vn->sc_vp && bp->b_cmd == BUF_CMD_FREEBLKS) {
308 * Freeblks is not handled for vnode-backed elements yet.
311 /* operation complete */
312 } else if (vn->sc_vp) {
316 * If an error occurs, we set B_ERROR but we do not set
317 * B_INVAL because (for a write anyway), the buffer is
323 bzero(&auio, sizeof(auio));
325 aiov.iov_base = bp->b_data;
326 aiov.iov_len = bp->b_bcount;
327 auio.uio_iov = &aiov;
329 auio.uio_offset = nbio->bio_offset;
330 auio.uio_segflg = UIO_SYSSPACE;
331 if (bp->b_cmd == BUF_CMD_READ)
332 auio.uio_rw = UIO_READ;
334 auio.uio_rw = UIO_WRITE;
335 auio.uio_resid = bp->b_bcount;
336 auio.uio_td = curthread;
339 * Don't use IO_DIRECT here, it really gets in the way
340 * due to typical blocksize differences between the
341 * fs backing the VN device and whatever is running on
344 if (bp->b_cmd == BUF_CMD_READ) {
345 vn_lock(vn->sc_vp, LK_SHARED | LK_RETRY);
346 error = VOP_READ(vn->sc_vp, &auio, IO_RECURSE,
349 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY);
350 error = VOP_WRITE(vn->sc_vp, &auio, IO_RECURSE,
353 vn_unlock(vn->sc_vp);
354 bp->b_resid = auio.uio_resid;
357 bp->b_flags |= B_ERROR;
359 /* operation complete */
360 } else if (vn->sc_object) {
362 * OBJT_SWAP I/O (handles read, write, freebuf)
364 * We have nothing to do if freeing blocks on a reserved
365 * swap area, othrewise execute the op.
367 if (bp->b_cmd == BUF_CMD_FREEBLKS && TESTOPT(vn, VN_RESERVE)) {
369 /* operation complete */
371 swap_pager_strategy(vn->sc_object, nbio);
376 bp->b_resid = bp->b_bcount;
377 bp->b_flags |= B_ERROR | B_INVAL;
378 bp->b_error = EINVAL;
379 /* operation complete */
387 vnioctl(struct dev_ioctl_args *ap)
389 cdev_t dev = ap->a_head.a_dev;
391 struct vn_ioctl *vio;
396 IFOPT(vn,VN_FOLLOW) {
397 kprintf("vnioctl(%s, 0x%lx, %p, 0x%x): unit %d\n",
398 devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag,
414 if (dkslice(dev) != WHOLE_DISK_SLICE ||
415 dkpart(dev) != WHOLE_SLICE_PART)
421 error = priv_check_cred(ap->a_cred, PRIV_ROOT, 0);
425 vio = (struct vn_ioctl *)ap->a_data;
426 f = (u_long*)ap->a_data;
430 if (vn->sc_flags & VNF_INITED)
433 if (vn->sc_flags & VNF_DESTROY)
436 if (vio->vn_file == NULL)
437 error = vniocattach_swap(vn, vio, dev, ap->a_fflag, ap->a_cred);
439 error = vniocattach_file(vn, vio, dev, ap->a_fflag, ap->a_cred);
443 if ((vn->sc_flags & VNF_INITED) == 0)
446 * XXX handle i/o in progress. Return EBUSY, or wait, or
448 * XXX handle multiple opens of the device. Return EBUSY,
449 * or revoke the fd's.
450 * How are these problems handled for removable and failing
451 * hardware devices? (Hint: They are not)
453 if ((disk_getopencount(&vn->sc_disk)) > 1)
458 kprintf("vnioctl: CLRed\n");
460 if (dkunit(dev) >= VN_PREALLOCATED_UNITS) {
461 vn->sc_flags |= VNF_DESTROY;
467 error = vnget(dev, vn, (struct vn_user *) ap->a_data);
481 vn->sc_options |= *f;
486 vn->sc_options &= ~(*f);
500 * Attach a file to a VN partition. Return the size in the vn_size
505 vniocattach_file(struct vn_softc *vn, struct vn_ioctl *vio, cdev_t dev,
506 int flag, struct ucred *cred)
509 struct nlookupdata nd;
512 struct disk_info info;
514 flags = FREAD|FWRITE;
515 error = nlookup_init(&nd, vio->vn_file,
516 UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
519 if ((error = vn_open(&nd, NULL, flags, 0)) != 0) {
520 if (error != EACCES && error != EPERM && error != EROFS)
524 error = nlookup_init(&nd, vio->vn_file, UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
527 if ((error = vn_open(&nd, NULL, flags, 0)) != 0)
531 if (vp->v_type != VREG ||
532 (error = VOP_GETATTR(vp, &vattr))) {
538 vn->sc_secsize = DEV_BSIZE;
540 nd.nl_open_vp = NULL;
543 * If the size is specified, override the file attributes. Note that
544 * the vn_size argument is in PAGE_SIZE sized blocks.
547 vn->sc_size = vio->vn_size * PAGE_SIZE / vn->sc_secsize;
549 vn->sc_size = vattr.va_size / vn->sc_secsize;
550 error = vnsetcred(vn, cred);
556 vn->sc_flags |= VNF_INITED;
558 vn->sc_flags |= VNF_READONLY;
561 * Set the disk info so that probing is triggered
563 bzero(&info, sizeof(struct disk_info));
564 info.d_media_blksize = vn->sc_secsize;
565 info.d_media_blocks = vn->sc_size;
567 * reserve mbr sector for backwards compatibility
568 * when no slices exist.
570 info.d_dsflags = DSO_COMPATMBR;
571 info.d_secpertrack = 32;
572 info.d_nheads = 64 / (vn->sc_secsize / DEV_BSIZE);
573 info.d_secpercyl = info.d_secpertrack * info.d_nheads;
574 info.d_ncylinders = vn->sc_size / info.d_secpercyl;
575 disk_setdiskinfo_sync(&vn->sc_disk, &info);
577 error = dev_dopen(dev, flag, S_IFCHR, cred);
582 kprintf("vnioctl: SET vp %p size %llx blks\n",
583 vn->sc_vp, (long long)vn->sc_size);
592 * Attach swap backing store to a VN partition of the size specified
597 vniocattach_swap(struct vn_softc *vn, struct vn_ioctl *vio, cdev_t dev,
598 int flag, struct ucred *cred)
601 struct disk_info info;
604 * Range check. Disallow negative sizes or any size less then the
605 * size of a page. Then round to a page.
608 if (vio->vn_size <= 0)
612 * Allocate an OBJT_SWAP object.
614 * sc_secsize is PAGE_SIZE'd
616 * vio->vn_size is in PAGE_SIZE'd chunks.
617 * sc_size must be in PAGE_SIZE'd chunks.
618 * Note the truncation.
621 vn->sc_secsize = PAGE_SIZE;
622 vn->sc_size = vio->vn_size;
623 vn->sc_object = swap_pager_alloc(NULL,
624 vn->sc_secsize * (off_t)vio->vn_size,
626 IFOPT(vn, VN_RESERVE) {
627 if (swap_pager_reserve(vn->sc_object, 0, vn->sc_size) < 0) {
628 vm_pager_deallocate(vn->sc_object);
629 vn->sc_object = NULL;
633 vn->sc_flags |= VNF_INITED;
635 error = vnsetcred(vn, cred);
638 * Set the disk info so that probing is triggered
640 bzero(&info, sizeof(struct disk_info));
641 info.d_media_blksize = vn->sc_secsize;
642 info.d_media_blocks = vn->sc_size;
644 * reserve mbr sector for backwards compatibility
645 * when no slices exist.
647 info.d_dsflags = DSO_COMPATMBR;
648 info.d_secpertrack = 32;
649 info.d_nheads = 64 / (vn->sc_secsize / DEV_BSIZE);
650 info.d_secpercyl = info.d_secpertrack * info.d_nheads;
651 info.d_ncylinders = vn->sc_size / info.d_secpercyl;
652 disk_setdiskinfo_sync(&vn->sc_disk, &info);
654 error = dev_dopen(dev, flag, S_IFCHR, cred);
657 IFOPT(vn, VN_FOLLOW) {
658 kprintf("vnioctl: SET vp %p size %llx\n",
659 vn->sc_vp, (long long)vn->sc_size);
668 * Duplicate the current processes' credentials. Since we are called only
669 * as the result of a SET ioctl and only root can do that, any future access
670 * to this "disk" is essentially as root. Note that credentials may change
671 * if some other uid can write directly to the mapped file (NFS).
674 vnsetcred(struct vn_softc *vn, struct ucred *cred)
680 * Set credits in our softc
685 vn->sc_cred = crdup(cred);
688 * Horrible kludge to establish credentials for NFS XXX.
695 tmpbuf = kmalloc(vn->sc_secsize, M_TEMP, M_WAITOK);
696 bzero(&auio, sizeof(auio));
698 aiov.iov_base = tmpbuf;
699 aiov.iov_len = vn->sc_secsize;
700 auio.uio_iov = &aiov;
703 auio.uio_rw = UIO_READ;
704 auio.uio_segflg = UIO_SYSSPACE;
705 auio.uio_resid = aiov.iov_len;
706 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY);
707 error = VOP_READ(vn->sc_vp, &auio, 0, vn->sc_cred);
708 vn_unlock(vn->sc_vp);
709 kfree(tmpbuf, M_TEMP);
715 vnclear(struct vn_softc *vn)
718 kprintf("vnclear(%p): vp=%p\n", vn, vn->sc_vp);
719 vn->sc_flags &= ~VNF_INITED;
720 if (vn->sc_vp != NULL) {
722 (vn->sc_flags & VNF_READONLY) ? FREAD : (FREAD|FWRITE));
725 vn->sc_flags &= ~VNF_READONLY;
730 if (vn->sc_object != NULL) {
731 vm_pager_deallocate(vn->sc_object);
732 vn->sc_object = NULL;
735 disk_unprobe(&vn->sc_disk);
743 * populate a struct vn_user for the VNIOCGET ioctl.
744 * interface conventions defined in sys/sys/vnioctl.h.
748 vnget(cdev_t dev, struct vn_softc *vn, struct vn_user *vnu)
750 int error, found = 0;
751 char *freepath, *fullpath;
754 if (vnu->vnu_unit == -1) {
755 vnu->vnu_unit = dkunit(dev);
757 else if (vnu->vnu_unit < 0)
760 SLIST_FOREACH(vn, &vn_list, sc_list) {
762 if(vn->sc_unit != vnu->vnu_unit)
767 if (vn->sc_flags & VNF_INITED && vn->sc_vp != NULL) {
769 /* note: u_cred checked in vnioctl above */
770 error = VOP_GETATTR(vn->sc_vp, &vattr);
772 kprintf("vnget: VOP_GETATTR for %p failed\n",
777 error = vn_fullpath(curproc, vn->sc_vp,
778 &fullpath, &freepath, 0);
781 kprintf("vnget: unable to resolve vp %p\n",
786 strlcpy(vnu->vnu_file, fullpath,
787 sizeof(vnu->vnu_file));
788 kfree(freepath, M_TEMP);
789 vnu->vnu_dev = vattr.va_fsid;
790 vnu->vnu_ino = vattr.va_fileid;
793 else if (vn->sc_flags & VNF_INITED && vn->sc_object != NULL){
795 strlcpy(vnu->vnu_file, _VN_USER_SWAP,
796 sizeof(vnu->vnu_file));
797 vnu->vnu_size = vn->sc_size;
798 vnu->vnu_secsize = vn->sc_secsize;
802 bzero(vnu->vnu_file, sizeof(vnu->vnu_file));
817 vnsize(struct dev_psize_args *ap)
819 cdev_t dev = ap->a_head.a_dev;
825 if ((vn->sc_flags & VNF_INITED) == 0)
827 ap->a_result = (int64_t)vn->sc_size;
832 vn_create(int unit, struct devfs_bitmap *bitmap, int clone)
835 struct disk_info info;
841 * For clone devices we need to return the top-level cdev,
842 * not the raw dev we'd normally work with.
844 dev = disk_create_clone(unit, &vn->sc_disk, &vn_ops);
845 ret_dev = vn->sc_disk.d_cdev;
847 ret_dev = dev = disk_create(unit, &vn->sc_disk, &vn_ops);
851 bzero(&info, sizeof(struct disk_info));
852 info.d_media_blksize = 512;
853 info.d_media_blocks = 0;
854 info.d_dsflags = DSO_MBRQUIET;
855 info.d_secpertrack = 32;
857 info.d_secpercyl = info.d_secpertrack * info.d_nheads;
858 info.d_ncylinders = 0;
859 disk_setdiskinfo_sync(&vn->sc_disk, &info);
862 devfs_clone_bitmap_set(bitmap, unit);
868 vn_modevent(module_t mod, int type, void *data)
871 static cdev_t dev = NULL;
876 dev = make_autoclone_dev(&vn_ops, &DEVFS_CLONE_BITMAP(vn), vnclone, UID_ROOT,
877 GID_OPERATOR, 0640, "vn");
879 for (i = 0; i < VN_PREALLOCATED_UNITS; i++) {
880 vn_create(i, &DEVFS_CLONE_BITMAP(vn), 0);
886 while ((vn = SLIST_FIRST(&vn_list)) != NULL) {
888 * XXX: no idea if we can return EBUSY even in the
889 * shutdown case, so err on the side of caution
890 * and just rip stuff out on shutdown.
892 if (type != MOD_SHUTDOWN) {
893 if (vn->sc_flags & VNF_OPENED)
897 disk_destroy(&vn->sc_disk);
899 SLIST_REMOVE_HEAD(&vn_list, sc_list);
901 if (vn->sc_flags & VNF_INITED)
906 destroy_autoclone_dev(dev, &DEVFS_CLONE_BITMAP(vn));
907 dev_ops_remove_all(&vn_ops);
915 DEV_MODULE(vn, vn_modevent, 0);