1 /*
2 * Copyright (c) 1988 University of Utah.
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
8 * Science Department.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
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. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * from: Utah Hdr: vn.c 1.13 94/04/02
35 *
36 * from: @(#)vn.c 8.6 (Berkeley) 4/1/94
37 * $FreeBSD: src/sys/dev/vn/vn.c,v 1.105.2.4 2001/11/18 07:11:00 dillon Exp $
38 */
39
40 /*
41 * Vnode disk driver.
42 *
43 * Block/character interface to a vnode. Allows one to treat a file
44 * as a disk (e.g. build a filesystem in it, mount it, etc.).
45 *
46 * NOTE 1: There is a security issue involved with this driver.
47 * Once mounted all access to the contents of the "mapped" file via
48 * the special file is controlled by the permissions on the special
49 * file, the protection of the mapped file is ignored (effectively,
50 * by using root credentials in all transactions).
51 *
52 * NOTE 2: Doesn't interact with leases, should it?
53 */
54
55 #include "use_vn.h"
56 #include <sys/param.h>
57 #include <sys/systm.h>
58 #include <sys/uio.h>
59 #include <sys/kernel.h>
60 #include <sys/proc.h>
61 #include <sys/caps.h>
62 #include <sys/nlookup.h>
63 #include <sys/buf.h>
64 #include <sys/malloc.h>
65 #include <sys/mount.h>
66 #include <sys/vnode.h>
67 #include <sys/fcntl.h>
68 #include <sys/conf.h>
69 #include <sys/diskslice.h>
70 #include <sys/disk.h>
71 #include <sys/stat.h>
72 #include <sys/module.h>
73 #include <sys/vnioctl.h>
74
75 #include <vm/vm.h>
76 #include <vm/vm_object.h>
77 #include <vm/vm_page.h>
78 #include <vm/vm_pager.h>
79 #include <vm/vm_pageout.h>
80 #include <vm/swap_pager.h>
81 #include <vm/vm_extern.h>
82 #include <vm/vm_zone.h>
83 #include <sys/devfs.h>
84
85 static d_ioctl_t vnioctl;
86 static d_open_t vnopen;
87 static d_close_t vnclose;
88 static d_psize_t vnsize;
89 static d_strategy_t vnstrategy;
90 static d_clone_t vnclone;
91
92 MALLOC_DEFINE(M_VN, "vn_softc", "vn driver structures");
93 DEVFS_DEFINE_CLONE_BITMAP(vn);
94
95 #if NVN <= 1
96 #define VN_PREALLOCATED_UNITS 4
97 #else
98 #define VN_PREALLOCATED_UNITS NVN
99 #endif
100
101 #define VN_BSIZE_BEST 8192
102
103 /*
104 * dev_ops
105 * D_DISK We want to look like a disk
106 * D_CANFREE We support BUF_CMD_FREEBLKS
107 * D_NOEMERGPGR Too complex for emergency pager
108 */
109
110 static struct dev_ops vn_ops = {
111 { "vn", 0, D_DISK | D_CANFREE | D_NOEMERGPGR },
112 .d_open = vnopen,
113 .d_close = vnclose,
114 .d_read = physread,
115 .d_write = physwrite,
116 .d_ioctl = vnioctl,
117 .d_strategy = vnstrategy,
118 .d_psize = vnsize
119 };
120
121 struct vn_softc {
122 int sc_unit;
123 int sc_flags; /* flags */
124 u_int64_t sc_size; /* size of vn, sc_secsize scale */
125 int sc_secsize; /* sector size */
126 struct disk sc_disk;
127 struct vnode *sc_vp; /* vnode if not NULL */
128 vm_object_t sc_object; /* backing object if not NULL */
129 struct ucred *sc_cred; /* credentials */
130 int sc_maxactive; /* max # of active requests */
131 struct buf sc_tab; /* transfer queue */
132 u_long sc_options; /* options */
133 cdev_t sc_dev; /* devices that refer to this unit */
134 SLIST_ENTRY(vn_softc) sc_list;
135 };
136
137 static SLIST_HEAD(, vn_softc) vn_list;
138
139 /* sc_flags */
140 #define VNF_INITED 0x01
141 #define VNF_READONLY 0x02
142 #define VNF_OPENED 0x10
143 #define VNF_DESTROY 0x20
144
145 static u_long vn_options;
146
147 #define IFOPT(vn,opt) if (((vn)->sc_options|vn_options) & (opt))
148 #define TESTOPT(vn,opt) (((vn)->sc_options|vn_options) & (opt))
149
150 static int vnsetcred (struct vn_softc *vn, struct ucred *cred);
151 static void vnclear (struct vn_softc *vn);
152 static int vnget (cdev_t dev, struct vn_softc *vn , struct vn_user *vnu);
153 static int vn_modevent (module_t, int, void *);
154 static int vniocattach_file (struct vn_softc *, struct vn_ioctl *, cdev_t dev, int flag, struct ucred *cred);
155 static int vniocattach_swap (struct vn_softc *, struct vn_ioctl *, cdev_t dev, int flag, struct ucred *cred);
156 static cdev_t vn_create(int unit, int clone);
157
158 static int
vnclone(struct dev_clone_args * ap)159 vnclone(struct dev_clone_args *ap)
160 {
161 int unit;
162
163 unit = devfs_clone_bitmap_get(&DEVFS_CLONE_BITMAP(vn), 0);
164 ap->a_dev = vn_create(unit, 1);
165
166 return 0;
167 }
168
169 static int
vnclose(struct dev_close_args * ap)170 vnclose(struct dev_close_args *ap)
171 {
172 cdev_t dev = ap->a_head.a_dev;
173 struct vn_softc *vn;
174
175 vn = dev->si_drv1;
176 KKASSERT(vn != NULL);
177
178 vn->sc_flags &= ~VNF_OPENED;
179
180 /* The disk has been detached and can now be safely destroyed */
181 if (vn->sc_flags & VNF_DESTROY) {
182 KKASSERT(disk_getopencount(&vn->sc_disk) == 0);
183 disk_destroy(&vn->sc_disk);
184 devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(vn), dkunit(dev));
185 SLIST_REMOVE(&vn_list, vn, vn_softc, sc_list);
186 kfree(vn, M_VN);
187 }
188 return (0);
189 }
190
191 static struct vn_softc *
vncreatevn(void)192 vncreatevn(void)
193 {
194 struct vn_softc *vn;
195
196 vn = kmalloc(sizeof *vn, M_VN, M_WAITOK | M_ZERO);
197 return vn;
198 }
199
200 static void
vninitvn(struct vn_softc * vn,cdev_t dev)201 vninitvn(struct vn_softc *vn, cdev_t dev)
202 {
203 int unit;
204
205 KKASSERT(vn != NULL);
206 KKASSERT(dev != NULL);
207 unit = dkunit(dev);
208
209 vn->sc_unit = unit;
210 dev->si_drv1 = vn;
211 vn->sc_dev = dev;
212
213 SLIST_INSERT_HEAD(&vn_list, vn, sc_list);
214 }
215
216 static int
vnopen(struct dev_open_args * ap)217 vnopen(struct dev_open_args *ap)
218 {
219 cdev_t dev = ap->a_head.a_dev;
220 struct vn_softc *vn;
221
222 /*
223 * Locate preexisting device
224 */
225
226 vn = dev->si_drv1;
227 KKASSERT(vn != NULL);
228
229 /*
230 * Update si_bsize fields for device. This data will be overridden by
231 * the slice/parition code for vn accesses through partitions, and
232 * used directly if you open the 'whole disk' device.
233 *
234 * si_bsize_best must be reinitialized in case VN has been
235 * reconfigured, plus make it at least VN_BSIZE_BEST for efficiency.
236 */
237 dev->si_bsize_phys = vn->sc_secsize;
238 dev->si_bsize_best = vn->sc_secsize;
239 if (dev->si_bsize_best < VN_BSIZE_BEST)
240 dev->si_bsize_best = VN_BSIZE_BEST;
241
242 if ((ap->a_oflags & FWRITE) && (vn->sc_flags & VNF_READONLY))
243 return (EACCES);
244
245 IFOPT(vn, VN_FOLLOW)
246 kprintf("vnopen(%s, 0x%x, 0x%x)\n",
247 devtoname(dev), ap->a_oflags, ap->a_devtype);
248
249 vn->sc_flags |= VNF_OPENED;
250 return(0);
251 }
252
253 /*
254 * vnstrategy:
255 *
256 * Run strategy routine for VN device. We use VOP_READ/VOP_WRITE calls
257 * for vnode-backed vn's, and the swap_pager_strategy() call for
258 * vm_object-backed vn's.
259 */
260 static int
vnstrategy(struct dev_strategy_args * ap)261 vnstrategy(struct dev_strategy_args *ap)
262 {
263 cdev_t dev = ap->a_head.a_dev;
264 struct bio *bio = ap->a_bio;
265 struct buf *bp;
266 struct bio *nbio;
267 int unit;
268 struct vn_softc *vn;
269 int error;
270
271 unit = dkunit(dev);
272 vn = dev->si_drv1;
273 KKASSERT(vn != NULL);
274
275 bp = bio->bio_buf;
276
277 IFOPT(vn, VN_DEBUG)
278 kprintf("vnstrategy(%p): unit %d\n", bp, unit);
279
280 if ((vn->sc_flags & VNF_INITED) == 0) {
281 bp->b_error = ENXIO;
282 bp->b_flags |= B_ERROR;
283 biodone(bio);
284 return(0);
285 }
286
287 bp->b_resid = bp->b_bcount;
288
289 /*
290 * The vnode device is using disk/slice label support.
291 *
292 * The dscheck() function is called for validating the
293 * slices that exist ON the vnode device itself, and
294 * translate the "slice-relative" block number, again.
295 * dscheck() will call biodone() and return NULL if
296 * we are at EOF or beyond the device size.
297 */
298
299 nbio = bio;
300
301 /*
302 * Use the translated nbio from this point on
303 */
304 if (vn->sc_vp && bp->b_cmd == BUF_CMD_FREEBLKS) {
305 /*
306 * Freeblks is not handled for vnode-backed elements yet.
307 */
308 bp->b_resid = 0;
309 /* operation complete */
310 } else if (vn->sc_vp) {
311 /*
312 * VNODE I/O
313 *
314 * If an error occurs, we set B_ERROR but we do not set
315 * B_INVAL because (for a write anyway), the buffer is
316 * still valid.
317 */
318 struct uio auio;
319 struct iovec aiov;
320
321 bzero(&auio, sizeof(auio));
322
323 aiov.iov_base = bp->b_data;
324 aiov.iov_len = bp->b_bcount;
325 auio.uio_iov = &aiov;
326 auio.uio_iovcnt = 1;
327 auio.uio_offset = nbio->bio_offset;
328 auio.uio_segflg = UIO_SYSSPACE;
329 if (bp->b_cmd == BUF_CMD_READ)
330 auio.uio_rw = UIO_READ;
331 else
332 auio.uio_rw = UIO_WRITE;
333 auio.uio_resid = bp->b_bcount;
334 auio.uio_td = curthread;
335
336 /*
337 * Don't use IO_DIRECT here, it really gets in the way
338 * due to typical blocksize differences between the
339 * fs backing the VN device and whatever is running on
340 * the VN device.
341 */
342 switch (bp->b_cmd) {
343 case (BUF_CMD_READ):
344 vn_lock(vn->sc_vp, LK_SHARED | LK_RETRY);
345 error = VOP_READ(vn->sc_vp, &auio, IO_RECURSE,
346 vn->sc_cred);
347 break;
348
349 case (BUF_CMD_WRITE):
350 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY);
351 error = VOP_WRITE(vn->sc_vp, &auio, IO_RECURSE,
352 vn->sc_cred);
353 break;
354
355 case (BUF_CMD_FLUSH):
356 auio.uio_resid = 0;
357 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY);
358 error = VOP_FSYNC(vn->sc_vp, MNT_WAIT, 0);
359 break;
360 default:
361 auio.uio_resid = 0;
362 error = 0;
363 goto breakunlocked;
364 }
365 vn_unlock(vn->sc_vp);
366 breakunlocked:
367 bp->b_resid = auio.uio_resid;
368 if (error) {
369 bp->b_error = error;
370 bp->b_flags |= B_ERROR;
371 }
372 /* operation complete */
373 } else if (vn->sc_object) {
374 /*
375 * OBJT_SWAP I/O (handles read, write, freebuf)
376 *
377 * We have nothing to do if freeing blocks on a reserved
378 * swap area, othrewise execute the op.
379 */
380 if (bp->b_cmd == BUF_CMD_FREEBLKS && TESTOPT(vn, VN_RESERVE)) {
381 bp->b_resid = 0;
382 /* operation complete */
383 } else {
384 swap_pager_strategy(vn->sc_object, nbio);
385 return(0);
386 /* NOT REACHED */
387 }
388 } else {
389 bp->b_resid = bp->b_bcount;
390 bp->b_flags |= B_ERROR | B_INVAL;
391 bp->b_error = EINVAL;
392 /* operation complete */
393 }
394 biodone(nbio);
395 return(0);
396 }
397
398 /* ARGSUSED */
399 static int
vnioctl(struct dev_ioctl_args * ap)400 vnioctl(struct dev_ioctl_args *ap)
401 {
402 cdev_t dev = ap->a_head.a_dev;
403 struct vn_softc *vn;
404 struct vn_ioctl *vio;
405 int error;
406 u_long *f;
407
408 vn = dev->si_drv1;
409 IFOPT(vn,VN_FOLLOW) {
410 kprintf("vnioctl(%s, 0x%lx, %p, 0x%x): unit %d\n",
411 devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag,
412 dkunit(dev));
413 }
414
415 switch (ap->a_cmd) {
416 case VNIOCATTACH:
417 case VNIOCDETACH:
418 case VNIOCGSET:
419 case VNIOCGCLEAR:
420 case VNIOCGET:
421 case VNIOCUSET:
422 case VNIOCUCLEAR:
423 goto vn_specific;
424 }
425
426 #if 0
427 if (dkslice(dev) != WHOLE_DISK_SLICE ||
428 dkpart(dev) != WHOLE_SLICE_PART)
429 return (ENOTTY);
430 #endif
431
432 vn_specific:
433
434 error = caps_priv_check(ap->a_cred, SYSCAP_RESTRICTEDROOT);
435 if (error)
436 return (error);
437
438 vio = (struct vn_ioctl *)ap->a_data;
439 f = (u_long*)ap->a_data;
440
441 switch (ap->a_cmd) {
442 case VNIOCATTACH:
443 if (vn->sc_flags & VNF_INITED)
444 return(EBUSY);
445
446 if (vn->sc_flags & VNF_DESTROY)
447 return(ENXIO);
448
449 if (vio->vn_file == NULL)
450 error = vniocattach_swap(vn, vio, dev, ap->a_fflag, ap->a_cred);
451 else
452 error = vniocattach_file(vn, vio, dev, ap->a_fflag, ap->a_cred);
453 break;
454
455 case VNIOCDETACH:
456 if ((vn->sc_flags & VNF_INITED) == 0)
457 return(ENXIO);
458 /*
459 * XXX handle i/o in progress. Return EBUSY, or wait, or
460 * flush the i/o.
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)
465 */
466 if ((disk_getopencount(&vn->sc_disk)) > 1)
467 return (EBUSY);
468
469 vnclear(vn);
470 IFOPT(vn, VN_FOLLOW)
471 kprintf("vnioctl: CLRed\n");
472
473 if (dkunit(dev) >= VN_PREALLOCATED_UNITS) {
474 vn->sc_flags |= VNF_DESTROY;
475 }
476
477 break;
478
479 case VNIOCGET:
480 error = vnget(dev, vn, (struct vn_user *) ap->a_data);
481 break;
482
483 case VNIOCGSET:
484 vn_options |= *f;
485 *f = vn_options;
486 break;
487
488 case VNIOCGCLEAR:
489 vn_options &= ~(*f);
490 *f = vn_options;
491 break;
492
493 case VNIOCUSET:
494 vn->sc_options |= *f;
495 *f = vn->sc_options;
496 break;
497
498 case VNIOCUCLEAR:
499 vn->sc_options &= ~(*f);
500 *f = vn->sc_options;
501 break;
502
503 default:
504 error = ENOTTY;
505 break;
506 }
507 return(error);
508 }
509
510 /*
511 * vniocattach_file:
512 *
513 * Attach a file to a VN partition. Return the size in the vn_size
514 * field.
515 */
516
517 static int
vniocattach_file(struct vn_softc * vn,struct vn_ioctl * vio,cdev_t dev,int flag,struct ucred * cred)518 vniocattach_file(struct vn_softc *vn, struct vn_ioctl *vio, cdev_t dev,
519 int flag, struct ucred *cred)
520 {
521 struct vattr vattr;
522 struct nlookupdata nd;
523 int error, flags;
524 struct vnode *vp;
525 struct disk_info info;
526
527 flags = FREAD|FWRITE;
528 error = nlookup_init(&nd, vio->vn_file,
529 UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
530 if (error)
531 return (error);
532 if ((error = vn_open(&nd, NULL, flags, 0)) != 0) {
533 if (error != EACCES && error != EPERM && error != EROFS)
534 goto done;
535 flags &= ~FWRITE;
536 nlookup_done(&nd);
537 error = nlookup_init(&nd, vio->vn_file, UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
538 if (error)
539 return (error);
540 if ((error = vn_open(&nd, NULL, flags, 0)) != 0)
541 goto done;
542 }
543 vp = nd.nl_open_vp;
544 if (vp->v_type != VREG ||
545 (error = VOP_GETATTR(vp, &vattr))) {
546 if (error == 0)
547 error = EINVAL;
548 goto done;
549 }
550 vn_unlock(vp);
551 vn->sc_secsize = DEV_BSIZE;
552 vn->sc_vp = vp;
553 nd.nl_open_vp = NULL;
554
555 /*
556 * If the size is specified, override the file attributes. Note that
557 * the vn_size argument is in PAGE_SIZE sized blocks.
558 */
559 if (vio->vn_size)
560 vn->sc_size = vio->vn_size * PAGE_SIZE / vn->sc_secsize;
561 else
562 vn->sc_size = vattr.va_size / vn->sc_secsize;
563 error = vnsetcred(vn, cred);
564 if (error) {
565 vn->sc_vp = NULL;
566 vn_close(vp, flags, NULL);
567 goto done;
568 }
569 vn->sc_flags |= VNF_INITED;
570 if (flags == FREAD)
571 vn->sc_flags |= VNF_READONLY;
572
573 /*
574 * Set the disk info so that probing is triggered
575 */
576 bzero(&info, sizeof(struct disk_info));
577 info.d_media_blksize = vn->sc_secsize;
578 info.d_media_blocks = vn->sc_size;
579 /*
580 * reserve mbr sector for backwards compatibility
581 * when no slices exist.
582 */
583 info.d_dsflags = DSO_COMPATMBR | DSO_RAWPSIZE;
584 info.d_secpertrack = 32;
585 info.d_nheads = 64 / (vn->sc_secsize / DEV_BSIZE);
586 info.d_secpercyl = info.d_secpertrack * info.d_nheads;
587 info.d_ncylinders = vn->sc_size / info.d_secpercyl;
588 disk_setdiskinfo_sync(&vn->sc_disk, &info);
589
590 error = dev_dopen(dev, flag, S_IFCHR, cred, NULL, NULL);
591 if (error)
592 vnclear(vn);
593
594 IFOPT(vn, VN_FOLLOW)
595 kprintf("vnioctl: SET vp %p size %llx blks\n",
596 vn->sc_vp, (long long)vn->sc_size);
597 done:
598 nlookup_done(&nd);
599 return(error);
600 }
601
602 /*
603 * vniocattach_swap:
604 *
605 * Attach swap backing store to a VN partition of the size specified
606 * in vn_size.
607 */
608
609 static int
vniocattach_swap(struct vn_softc * vn,struct vn_ioctl * vio,cdev_t dev,int flag,struct ucred * cred)610 vniocattach_swap(struct vn_softc *vn, struct vn_ioctl *vio, cdev_t dev,
611 int flag, struct ucred *cred)
612 {
613 int error;
614 struct disk_info info;
615
616 /*
617 * Range check. Disallow negative sizes or any size less then the
618 * size of a page. Then round to a page.
619 */
620
621 if (vio->vn_size <= 0)
622 return(EDOM);
623
624 /*
625 * Allocate an OBJT_SWAP object.
626 *
627 * sc_secsize is PAGE_SIZE'd
628 *
629 * vio->vn_size is in PAGE_SIZE'd chunks.
630 * sc_size must be in PAGE_SIZE'd chunks.
631 * Note the truncation.
632 */
633
634 vn->sc_secsize = PAGE_SIZE;
635 vn->sc_size = vio->vn_size;
636 vn->sc_object = swap_pager_alloc(NULL,
637 vn->sc_secsize * (off_t)vio->vn_size,
638 VM_PROT_DEFAULT, 0);
639 vm_object_set_flag(vn->sc_object, OBJ_NOPAGEIN);
640 IFOPT(vn, VN_RESERVE) {
641 if (swap_pager_reserve(vn->sc_object, 0, vn->sc_size) < 0) {
642 vm_pager_deallocate(vn->sc_object);
643 vn->sc_object = NULL;
644 return(EDOM);
645 }
646 }
647 vn->sc_flags |= VNF_INITED;
648
649 error = vnsetcred(vn, cred);
650 if (error == 0) {
651 /*
652 * Set the disk info so that probing is triggered
653 */
654 bzero(&info, sizeof(struct disk_info));
655 info.d_media_blksize = vn->sc_secsize;
656 info.d_media_blocks = vn->sc_size;
657 /*
658 * reserve mbr sector for backwards compatibility
659 * when no slices exist.
660 */
661 info.d_dsflags = DSO_COMPATMBR | DSO_RAWPSIZE;
662 info.d_secpertrack = 32;
663 info.d_nheads = 64 / (vn->sc_secsize / DEV_BSIZE);
664 info.d_secpercyl = info.d_secpertrack * info.d_nheads;
665 info.d_ncylinders = vn->sc_size / info.d_secpercyl;
666 disk_setdiskinfo_sync(&vn->sc_disk, &info);
667
668 error = dev_dopen(dev, flag, S_IFCHR, cred, NULL, NULL);
669 }
670 if (error == 0) {
671 IFOPT(vn, VN_FOLLOW) {
672 kprintf("vnioctl: SET vp %p size %llx\n",
673 vn->sc_vp, (long long)vn->sc_size);
674 }
675 }
676 if (error)
677 vnclear(vn);
678 return(error);
679 }
680
681 /*
682 * Duplicate the current processes' credentials. Since we are called only
683 * as the result of a SET ioctl and only root can do that, any future access
684 * to this "disk" is essentially as root. Note that credentials may change
685 * if some other uid can write directly to the mapped file (NFS).
686 */
687 static int
vnsetcred(struct vn_softc * vn,struct ucred * cred)688 vnsetcred(struct vn_softc *vn, struct ucred *cred)
689 {
690 char *tmpbuf;
691 int error = 0;
692
693 /*
694 * Set credits in our softc
695 */
696
697 if (vn->sc_cred)
698 crfree(vn->sc_cred);
699 vn->sc_cred = crdup(cred);
700
701 /*
702 * Horrible kludge to establish credentials for NFS XXX.
703 */
704
705 if (vn->sc_vp) {
706 struct uio auio;
707 struct iovec aiov;
708
709 tmpbuf = kmalloc(vn->sc_secsize, M_TEMP, M_WAITOK);
710 bzero(&auio, sizeof(auio));
711
712 aiov.iov_base = tmpbuf;
713 aiov.iov_len = vn->sc_secsize;
714 auio.uio_iov = &aiov;
715 auio.uio_iovcnt = 1;
716 auio.uio_offset = 0;
717 auio.uio_rw = UIO_READ;
718 auio.uio_segflg = UIO_SYSSPACE;
719 auio.uio_resid = aiov.iov_len;
720 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY);
721 error = VOP_READ(vn->sc_vp, &auio, 0, vn->sc_cred);
722 vn_unlock(vn->sc_vp);
723 kfree(tmpbuf, M_TEMP);
724 }
725 return (error);
726 }
727
728 static void
vnclear(struct vn_softc * vn)729 vnclear(struct vn_softc *vn)
730 {
731 IFOPT(vn, VN_FOLLOW)
732 kprintf("vnclear(%p): vp=%p\n", vn, vn->sc_vp);
733 vn->sc_flags &= ~VNF_INITED;
734 if (vn->sc_vp != NULL) {
735 vn_close(vn->sc_vp,
736 (vn->sc_flags & VNF_READONLY) ? FREAD : (FREAD|FWRITE),
737 NULL);
738 vn->sc_vp = NULL;
739 }
740 vn->sc_flags &= ~VNF_READONLY;
741 if (vn->sc_cred) {
742 crfree(vn->sc_cred);
743 vn->sc_cred = NULL;
744 }
745 if (vn->sc_object != NULL) {
746 vm_pager_deallocate(vn->sc_object);
747 vn->sc_object = NULL;
748 }
749
750 disk_unprobe(&vn->sc_disk);
751
752 vn->sc_size = 0;
753 }
754
755 /*
756 * vnget:
757 *
758 * populate a struct vn_user for the VNIOCGET ioctl.
759 * interface conventions defined in sys/sys/vnioctl.h.
760 */
761
762 static int
vnget(cdev_t dev,struct vn_softc * vn,struct vn_user * vnu)763 vnget(cdev_t dev, struct vn_softc *vn, struct vn_user *vnu)
764 {
765 int error, found = 0;
766 char *freepath, *fullpath;
767 struct vattr vattr;
768
769 if (vnu->vnu_unit == -1) {
770 vnu->vnu_unit = dkunit(dev);
771 }
772 else if (vnu->vnu_unit < 0)
773 return (EINVAL);
774
775 SLIST_FOREACH(vn, &vn_list, sc_list) {
776
777 if(vn->sc_unit != vnu->vnu_unit)
778 continue;
779
780 found = 1;
781
782 if (vn->sc_flags & VNF_INITED && vn->sc_vp != NULL) {
783
784 /* note: u_cred checked in vnioctl above */
785 error = VOP_GETATTR(vn->sc_vp, &vattr);
786 if (error) {
787 kprintf("vnget: VOP_GETATTR for %p failed\n",
788 vn->sc_vp);
789 return (error);
790 }
791
792 error = vn_fullpath(curproc, vn->sc_vp,
793 &fullpath, &freepath, 0);
794
795 if (error) {
796 kprintf("vnget: unable to resolve vp %p\n",
797 vn->sc_vp);
798 return(error);
799 }
800
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;
806
807 }
808 else if (vn->sc_flags & VNF_INITED && vn->sc_object != NULL){
809
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;
814
815 } else {
816
817 bzero(vnu->vnu_file, sizeof(vnu->vnu_file));
818 vnu->vnu_dev = 0;
819 vnu->vnu_ino = 0;
820
821 }
822 break;
823 }
824
825 if (!found)
826 return(ENXIO);
827
828 return(0);
829 }
830
831 static int
vnsize(struct dev_psize_args * ap)832 vnsize(struct dev_psize_args *ap)
833 {
834 cdev_t dev = ap->a_head.a_dev;
835 struct vn_softc *vn;
836
837 vn = dev->si_drv1;
838 if (!vn)
839 return(ENXIO);
840 if ((vn->sc_flags & VNF_INITED) == 0)
841 return(ENXIO);
842 ap->a_result = (int64_t)vn->sc_size;
843 return(0);
844 }
845
846 /*
847 * Returns NULL only if the specified unit cannot be allocated.
848 */
849 static cdev_t
vn_create(int unit,int clone)850 vn_create(int unit, int clone)
851 {
852 struct vn_softc *vn;
853 struct disk_info info;
854 cdev_t dev, ret_dev;
855
856 vn = vncreatevn();
857 if (clone) {
858 /*
859 * For clone devices we need to return the top-level cdev,
860 * not the raw dev we'd normally work with.
861 */
862 dev = disk_create_clone(unit, &vn->sc_disk, &vn_ops);
863 ret_dev = vn->sc_disk.d_cdev;
864 } else {
865 ret_dev = dev = disk_create(unit, &vn->sc_disk, &vn_ops);
866 }
867 vninitvn(vn, dev);
868
869 bzero(&info, sizeof(struct disk_info));
870 info.d_media_blksize = 512;
871 info.d_media_blocks = 0;
872 info.d_dsflags = DSO_MBRQUIET | DSO_RAWPSIZE;
873 info.d_secpertrack = 32;
874 info.d_nheads = 64;
875 info.d_secpercyl = info.d_secpertrack * info.d_nheads;
876 info.d_ncylinders = 0;
877 disk_setdiskinfo_sync(&vn->sc_disk, &info);
878
879 return ret_dev;
880 }
881
882 static int
vn_modevent(module_t mod,int type,void * data)883 vn_modevent(module_t mod, int type, void *data)
884 {
885 struct vn_softc *vn;
886 static cdev_t dev = NULL;
887 int i;
888
889 switch (type) {
890 case MOD_LOAD:
891 dev = make_autoclone_dev(&vn_ops, &DEVFS_CLONE_BITMAP(vn),
892 vnclone, UID_ROOT, GID_OPERATOR,
893 0640, "vn");
894 for (i = 0; i < VN_PREALLOCATED_UNITS; i++) {
895 devfs_clone_bitmap_set(&DEVFS_CLONE_BITMAP(vn), i);
896 vn_create(i, 0);
897 }
898 break;
899
900 case MOD_UNLOAD:
901 case MOD_SHUTDOWN:
902 while ((vn = SLIST_FIRST(&vn_list)) != NULL) {
903 /*
904 * XXX: no idea if we can return EBUSY even in the
905 * shutdown case, so err on the side of caution
906 * and just rip stuff out on shutdown.
907 */
908 if (type != MOD_SHUTDOWN) {
909 if (vn->sc_flags & VNF_OPENED)
910 return (EBUSY);
911 }
912
913 disk_destroy(&vn->sc_disk);
914
915 SLIST_REMOVE_HEAD(&vn_list, sc_list);
916
917 if (vn->sc_flags & VNF_INITED)
918 vnclear(vn);
919
920 kfree(vn, M_VN);
921 }
922 destroy_autoclone_dev(dev, &DEVFS_CLONE_BITMAP(vn));
923 dev_ops_remove_all(&vn_ops);
924 break;
925 default:
926 break;
927 }
928 return 0;
929 }
930
931 DEV_MODULE(vn, vn_modevent, 0);
932