1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #pragma ident "%Z%%M% %I% %E% SMI"
27
28 /*
29 * lofi (loopback file) driver - allows you to attach a file to a device,
30 * which can then be accessed through that device. The simple model is that
31 * you tell lofi to open a file, and then use the block device you get as
32 * you would any block device. lofi translates access to the block device
33 * into I/O on the underlying file. This is mostly useful for
34 * mounting images of filesystems.
35 *
36 * lofi is controlled through /dev/lofictl - this is the only device exported
37 * during attach, and is minor number 0. lofiadm communicates with lofi through
38 * ioctls on this device. When a file is attached to lofi, block and character
39 * devices are exported in /dev/lofi and /dev/rlofi. Currently, these devices
40 * are identified by their minor number, and the minor number is also used
41 * as the name in /dev/lofi. If we ever decide to support virtual disks,
42 * we'll have to divide the minor number space to identify fdisk partitions
43 * and slices, and the name will then be the minor number shifted down a
44 * few bits. Minor devices are tracked with state structures handled with
45 * ddi_soft_state(9F) for simplicity.
46 *
47 * A file attached to lofi is opened when attached and not closed until
48 * explicitly detached from lofi. This seems more sensible than deferring
49 * the open until the /dev/lofi device is opened, for a number of reasons.
50 * One is that any failure is likely to be noticed by the person (or script)
51 * running lofiadm. Another is that it would be a security problem if the
52 * file was replaced by another one after being added but before being opened.
53 *
54 * The only hard part about lofi is the ioctls. In order to support things
55 * like 'newfs' on a lofi device, it needs to support certain disk ioctls.
56 * So it has to fake disk geometry and partition information. More may need
57 * to be faked if your favorite utility doesn't work and you think it should
58 * (fdformat doesn't work because it really wants to know the type of floppy
59 * controller to talk to, and that didn't seem easy to fake. Or possibly even
60 * necessary, since we have mkfs_pcfs now).
61 *
62 * Normally, a lofi device cannot be detached if it is open (i.e. busy). To
63 * support simulation of hotplug events, an optional force flag is provided.
64 * If a lofi device is open when a force detach is requested, then the
65 * underlying file is closed and any subsequent operations return EIO. When the
66 * device is closed for the last time, it will be cleaned up at that time. In
67 * addition, the DKIOCSTATE ioctl will return DKIO_DEV_GONE when the device is
68 * detached but not removed.
69 *
70 * Known problems:
71 *
72 * UFS logging. Mounting a UFS filesystem image "logging"
73 * works for basic copy testing but wedges during a build of ON through
74 * that image. Some deadlock in lufs holding the log mutex and then
75 * getting stuck on a buf. So for now, don't do that.
76 *
77 * Direct I/O. Since the filesystem data is being cached in the buffer
78 * cache, _and_ again in the underlying filesystem, it's tempting to
79 * enable direct I/O on the underlying file. Don't, because that deadlocks.
80 * I think to fix the cache-twice problem we might need filesystem support.
81 *
82 * lofi on itself. The simple lock strategy (lofi_lock) precludes this
83 * because you'll be in lofi_ioctl, holding the lock when you open the
84 * file, which, if it's lofi, will grab lofi_lock. We prevent this for
85 * now, though not using ddi_soft_state(9F) would make it possible to
86 * do. Though it would still be silly.
87 *
88 * Interesting things to do:
89 *
90 * Allow multiple files for each device. A poor-man's metadisk, basically.
91 *
92 * Pass-through ioctls on block devices. You can (though it's not
93 * documented), give lofi a block device as a file name. Then we shouldn't
94 * need to fake a geometry. But this is also silly unless you're replacing
95 * metadisk.
96 *
97 * Encryption. tpm would like this. Apparently Windows 2000 has it, and
98 * so does Linux.
99 */
100
101 #include <sys/types.h>
102 #include <netinet/in.h>
103 #include <sys/sysmacros.h>
104 #include <sys/cmn_err.h>
105 #include <sys/uio.h>
106 #include <sys/kmem.h>
107 #include <sys/cred.h>
108 #include <sys/mman.h>
109 #include <sys/errno.h>
110 #include <sys/aio_req.h>
111 #include <sys/stat.h>
112 #include <sys/file.h>
113 #include <sys/modctl.h>
114 #include <sys/conf.h>
115 #include <sys/debug.h>
116 #include <sys/vnode.h>
117 #include <sys/lofi.h>
118 #include <sys/fcntl.h>
119 #include <sys/pathname.h>
120 #include <sys/filio.h>
121 #include <sys/fdio.h>
122 #include <sys/open.h>
123 #include <sys/disp.h>
124 #include <vm/seg_map.h>
125 #include <sys/ddi.h>
126 #include <sys/sunddi.h>
127 #include <sys/zmod.h>
128
129 #define NBLOCKS_PROP_NAME "Nblocks"
130 #define SIZE_PROP_NAME "Size"
131
132 static dev_info_t *lofi_dip;
133 static void *lofi_statep;
134 static kmutex_t lofi_lock; /* state lock */
135
136 /*
137 * Because lofi_taskq_nthreads limits the actual swamping of the device, the
138 * maxalloc parameter (lofi_taskq_maxalloc) should be tuned conservatively
139 * high. If we want to be assured that the underlying device is always busy,
140 * we must be sure that the number of bytes enqueued when the number of
141 * enqueued tasks exceeds maxalloc is sufficient to keep the device busy for
142 * the duration of the sleep time in taskq_ent_alloc(). That is, lofi should
143 * set maxalloc to be the maximum throughput (in bytes per second) of the
144 * underlying device divided by the minimum I/O size. We assume a realistic
145 * maximum throughput of one hundred megabytes per second; we set maxalloc on
146 * the lofi task queue to be 104857600 divided by DEV_BSIZE.
147 */
148 static int lofi_taskq_maxalloc = 104857600 / DEV_BSIZE;
149 static int lofi_taskq_nthreads = 4; /* # of taskq threads per device */
150
151 uint32_t lofi_max_files = LOFI_MAX_FILES;
152
153 static int gzip_decompress(void *src, size_t srclen, void *dst,
154 size_t *destlen, int level);
155
156 lofi_compress_info_t lofi_compress_table[LOFI_COMPRESS_FUNCTIONS] = {
157 {gzip_decompress, NULL, 6, "gzip"}, /* default */
158 {gzip_decompress, NULL, 6, "gzip-6"},
159 {gzip_decompress, NULL, 9, "gzip-9"}
160 };
161
162 static int
163 lofi_busy(void)
164 {
165 minor_t minor;
166
167 /*
168 * We need to make sure no mappings exist - mod_remove won't
169 * help because the device isn't open.
170 */
171 mutex_enter(&lofi_lock);
172 for (minor = 1; minor <= lofi_max_files; minor++) {
173 if (ddi_get_soft_state(lofi_statep, minor) != NULL) {
174 mutex_exit(&lofi_lock);
175 return (EBUSY);
176 }
177 }
178 mutex_exit(&lofi_lock);
179 return (0);
180 }
181
182 static int
183 is_opened(struct lofi_state *lsp)
184 {
185 ASSERT(mutex_owned(&lofi_lock));
186 return (lsp->ls_chr_open || lsp->ls_blk_open || lsp->ls_lyr_open_count);
187 }
188
189 static int
190 mark_opened(struct lofi_state *lsp, int otyp)
191 {
192 ASSERT(mutex_owned(&lofi_lock));
193 switch (otyp) {
194 case OTYP_CHR:
195 lsp->ls_chr_open = 1;
196 break;
197 case OTYP_BLK:
198 lsp->ls_blk_open = 1;
199 break;
200 case OTYP_LYR:
201 lsp->ls_lyr_open_count++;
202 break;
203 default:
204 return (-1);
205 }
206 return (0);
207 }
208
209 static void
210 mark_closed(struct lofi_state *lsp, int otyp)
211 {
212 ASSERT(mutex_owned(&lofi_lock));
213 switch (otyp) {
214 case OTYP_CHR:
215 lsp->ls_chr_open = 0;
216 break;
217 case OTYP_BLK:
218 lsp->ls_blk_open = 0;
219 break;
220 case OTYP_LYR:
221 lsp->ls_lyr_open_count--;
222 break;
223 default:
224 break;
225 }
226 }
227
228 static void
229 lofi_free_handle(dev_t dev, minor_t minor, struct lofi_state *lsp,
230 cred_t *credp)
231 {
232 dev_t newdev;
233 char namebuf[50];
234
235 if (lsp->ls_vp) {
236 (void) VOP_CLOSE(lsp->ls_vp, lsp->ls_openflag, 1, 0, credp);
237 VN_RELE(lsp->ls_vp);
238 lsp->ls_vp = NULL;
239 }
240
241 newdev = makedevice(getmajor(dev), minor);
242 (void) ddi_prop_remove(newdev, lofi_dip, SIZE_PROP_NAME);
243 (void) ddi_prop_remove(newdev, lofi_dip, NBLOCKS_PROP_NAME);
244
245 (void) snprintf(namebuf, sizeof (namebuf), "%d", minor);
246 ddi_remove_minor_node(lofi_dip, namebuf);
247 (void) snprintf(namebuf, sizeof (namebuf), "%d,raw", minor);
248 ddi_remove_minor_node(lofi_dip, namebuf);
249
250 kmem_free(lsp->ls_filename, lsp->ls_filename_sz);
251 taskq_destroy(lsp->ls_taskq);
252 if (lsp->ls_kstat) {
253 kstat_delete(lsp->ls_kstat);
254 mutex_destroy(&lsp->ls_kstat_lock);
255 }
256 ddi_soft_state_free(lofi_statep, minor);
257 }
258
259 /*ARGSUSED*/
260 static int
261 lofi_open(dev_t *devp, int flag, int otyp, struct cred *credp)
262 {
263 minor_t minor;
264 struct lofi_state *lsp;
265
266 mutex_enter(&lofi_lock);
267 minor = getminor(*devp);
268 if (minor == 0) {
269 /* master control device */
270 /* must be opened exclusively */
271 if (((flag & FEXCL) != FEXCL) || (otyp != OTYP_CHR)) {
272 mutex_exit(&lofi_lock);
273 return (EINVAL);
274 }
275 lsp = ddi_get_soft_state(lofi_statep, 0);
276 if (lsp == NULL) {
277 mutex_exit(&lofi_lock);
278 return (ENXIO);
279 }
280 if (is_opened(lsp)) {
281 mutex_exit(&lofi_lock);
282 return (EBUSY);
283 }
284 (void) mark_opened(lsp, OTYP_CHR);
285 mutex_exit(&lofi_lock);
286 return (0);
287 }
288
289 /* otherwise, the mapping should already exist */
290 lsp = ddi_get_soft_state(lofi_statep, minor);
291 if (lsp == NULL) {
292 mutex_exit(&lofi_lock);
293 return (EINVAL);
294 }
295
296 if (lsp->ls_vp == NULL) {
297 mutex_exit(&lofi_lock);
298 return (ENXIO);
299 }
300
301 if (mark_opened(lsp, otyp) == -1) {
302 mutex_exit(&lofi_lock);
303 return (EINVAL);
304 }
305
306 mutex_exit(&lofi_lock);
307 return (0);
308 }
309
310 /*ARGSUSED*/
311 static int
312 lofi_close(dev_t dev, int flag, int otyp, struct cred *credp)
313 {
314 minor_t minor;
315 struct lofi_state *lsp;
316
317 mutex_enter(&lofi_lock);
318 minor = getminor(dev);
319 lsp = ddi_get_soft_state(lofi_statep, minor);
320 if (lsp == NULL) {
321 mutex_exit(&lofi_lock);
322 return (EINVAL);
323 }
324 mark_closed(lsp, otyp);
325
326 /*
327 * If we have forcibly closed the underlying device, and this is the
328 * last close, then tear down the rest of the device.
329 */
330 if (minor != 0 && lsp->ls_vp == NULL && !is_opened(lsp))
331 lofi_free_handle(dev, minor, lsp, credp);
332 mutex_exit(&lofi_lock);
333 return (0);
334 }
335
336 static int
337 lofi_mapped_rdwr(caddr_t bufaddr, offset_t offset, struct buf *bp,
338 struct lofi_state *lsp)
339 {
340 int error;
341 offset_t alignedoffset, mapoffset;
342 size_t xfersize;
343 int isread;
344 int smflags;
345 caddr_t mapaddr;
346 size_t len;
347 enum seg_rw srw;
348
349 /*
350 * segmap always gives us an 8K (MAXBSIZE) chunk, aligned on
351 * an 8K boundary, but the buf transfer address may not be
352 * aligned on more than a 512-byte boundary (we don't enforce
353 * that even though we could). This matters since the initial
354 * part of the transfer may not start at offset 0 within the
355 * segmap'd chunk. So we have to compensate for that with
356 * 'mapoffset'. Subsequent chunks always start off at the
357 * beginning, and the last is capped by b_resid
358 */
359 mapoffset = offset & MAXBOFFSET;
360 alignedoffset = offset - mapoffset;
361 bp->b_resid = bp->b_bcount;
362 isread = bp->b_flags & B_READ;
363 srw = isread ? S_READ : S_WRITE;
364 do {
365 xfersize = MIN(lsp->ls_vp_comp_size - offset,
366 MIN(MAXBSIZE - mapoffset, bp->b_resid));
367 len = roundup(mapoffset + xfersize, PAGESIZE);
368 mapaddr = segmap_getmapflt(segkmap, lsp->ls_vp,
369 alignedoffset, MAXBSIZE, 1, srw);
370 /*
371 * Now fault in the pages. This lets us check
372 * for errors before we reference mapaddr and
373 * try to resolve the fault in bcopy (which would
374 * panic instead). And this can easily happen,
375 * particularly if you've lofi'd a file over NFS
376 * and someone deletes the file on the server.
377 */
378 error = segmap_fault(kas.a_hat, segkmap, mapaddr,
379 len, F_SOFTLOCK, srw);
380 if (error) {
381 (void) segmap_release(segkmap, mapaddr, 0);
382 if (FC_CODE(error) == FC_OBJERR)
383 error = FC_ERRNO(error);
384 else
385 error = EIO;
386 break;
387 }
388 smflags = 0;
389 if (isread) {
390 smflags |= SM_FREE;
391 /*
392 * If we're reading an entire page starting
393 * at a page boundary, there's a good chance
394 * we won't need it again. Put it on the
395 * head of the freelist.
396 */
397 if (mapoffset == 0 && xfersize == PAGESIZE)
398 smflags |= SM_DONTNEED;
399 bcopy(mapaddr + mapoffset, bufaddr, xfersize);
400 } else {
401 smflags |= SM_WRITE;
402 bcopy(bufaddr, mapaddr + mapoffset, xfersize);
403 }
404 bp->b_resid -= xfersize;
405 bufaddr += xfersize;
406 offset += xfersize;
407 (void) segmap_fault(kas.a_hat, segkmap, mapaddr,
408 len, F_SOFTUNLOCK, srw);
409 error = segmap_release(segkmap, mapaddr, smflags);
410 /* only the first map may start partial */
411 mapoffset = 0;
412 alignedoffset += MAXBSIZE;
413 } while ((error == 0) && (bp->b_resid > 0) &&
414 (offset < lsp->ls_vp_comp_size));
415
416 return (error);
417 }
418
419 /*ARGSUSED*/
420 static int gzip_decompress(void *src, size_t srclen, void *dst,
421 size_t *dstlen, int level)
422 {
423 ASSERT(*dstlen >= srclen);
424
425 if (z_uncompress(dst, dstlen, src, srclen) != Z_OK)
426 return (-1);
427 return (0);
428 }
429
430 /*
431 * This is basically what strategy used to be before we found we
432 * needed task queues.
433 */
434 static void
435 lofi_strategy_task(void *arg)
436 {
437 struct buf *bp = (struct buf *)arg;
438 int error;
439 struct lofi_state *lsp;
440 uint64_t sblkno, eblkno, cmpbytes;
441 offset_t offset, sblkoff, eblkoff;
442 offset_t salign, ealign;
443 offset_t sdiff;
444 uint32_t comp_data_sz;
445 caddr_t bufaddr;
446 unsigned char *compressed_seg = NULL, *cmpbuf;
447 unsigned char *uncompressed_seg = NULL;
448 lofi_compress_info_t *li;
449 size_t oblkcount, xfersize;
450 unsigned long seglen;
451
452 lsp = ddi_get_soft_state(lofi_statep, getminor(bp->b_edev));
453 if (lsp->ls_kstat) {
454 mutex_enter(lsp->ls_kstat->ks_lock);
455 kstat_waitq_to_runq(KSTAT_IO_PTR(lsp->ls_kstat));
456 mutex_exit(lsp->ls_kstat->ks_lock);
457 }
458 bp_mapin(bp);
459 bufaddr = bp->b_un.b_addr;
460 offset = bp->b_lblkno * DEV_BSIZE; /* offset within file */
461
462 /*
463 * We used to always use vn_rdwr here, but we cannot do that because
464 * we might decide to read or write from the the underlying
465 * file during this call, which would be a deadlock because
466 * we have the rw_lock. So instead we page, unless it's not
467 * mapable or it's a character device.
468 */
469 if (lsp->ls_vp == NULL || lsp->ls_vp_closereq) {
470 error = EIO;
471 } else if (((lsp->ls_vp->v_flag & VNOMAP) == 0) &&
472 (lsp->ls_vp->v_type != VCHR)) {
473 uint64_t i;
474
475 /*
476 * Handle uncompressed files with a regular read
477 */
478 if (lsp->ls_uncomp_seg_sz == 0) {
479 error = lofi_mapped_rdwr(bufaddr, offset, bp, lsp);
480 goto done;
481 }
482
483 /*
484 * From here on we're dealing primarily with compressed files
485 */
486
487 /*
488 * Compressed files can only be read from and
489 * not written to
490 */
491 if (!(bp->b_flags & B_READ)) {
492 bp->b_resid = bp->b_bcount;
493 error = EROFS;
494 goto done;
495 }
496
497 ASSERT(lsp->ls_comp_algorithm_index >= 0);
498 li = &lofi_compress_table[lsp->ls_comp_algorithm_index];
499 /*
500 * Compute starting and ending compressed segment numbers
501 * We use only bitwise operations avoiding division and
502 * modulus because we enforce the compression segment size
503 * to a power of 2
504 */
505 sblkno = offset >> lsp->ls_comp_seg_shift;
506 sblkoff = offset & (lsp->ls_uncomp_seg_sz - 1);
507 eblkno = (offset + bp->b_bcount) >> lsp->ls_comp_seg_shift;
508 eblkoff = (offset + bp->b_bcount) & (lsp->ls_uncomp_seg_sz - 1);
509
510 /*
511 * Align start offset to block boundary for segmap
512 */
513 salign = lsp->ls_comp_seg_index[sblkno];
514 sdiff = salign & (DEV_BSIZE - 1);
515 salign -= sdiff;
516 if (eblkno >= (lsp->ls_comp_index_sz - 1)) {
517 /*
518 * We're dealing with the last segment of
519 * the compressed file -- the size of this
520 * segment *may not* be the same as the
521 * segment size for the file
522 */
523 eblkoff = (offset + bp->b_bcount) &
524 (lsp->ls_uncomp_last_seg_sz - 1);
525 ealign = lsp->ls_vp_comp_size;
526 } else {
527 ealign = lsp->ls_comp_seg_index[eblkno + 1];
528 }
529
530 /*
531 * Preserve original request paramaters
532 */
533 oblkcount = bp->b_bcount;
534
535 /*
536 * Assign the calculated parameters
537 */
538 comp_data_sz = ealign - salign;
539 bp->b_bcount = comp_data_sz;
540
541 /*
542 * Allocate fixed size memory blocks to hold one
543 * compressed and uncompressed segment since we
544 * uncompress segments one at a time
545 */
546 compressed_seg = kmem_alloc(bp->b_bcount, KM_SLEEP);
547 uncompressed_seg = kmem_alloc(lsp->ls_uncomp_seg_sz, KM_SLEEP);
548 /*
549 * Map in the calculated number of blocks
550 */
551 error = lofi_mapped_rdwr((caddr_t)compressed_seg, salign,
552 bp, lsp);
553
554 bp->b_bcount = oblkcount;
555 bp->b_resid = oblkcount;
556 if (error != 0)
557 goto done;
558
559 /*
560 * We have the compressed blocks, now uncompress them
561 */
562 cmpbuf = compressed_seg + sdiff;
563 for (i = sblkno; i < (eblkno + 1) && i < lsp->ls_comp_index_sz;
564 i++) {
565 /*
566 * Each of the segment index entries contains
567 * the starting block number for that segment.
568 * The number of compressed bytes in a segment
569 * is thus the difference between the starting
570 * block number of this segment and the starting
571 * block number of the next segment.
572 */
573 if ((i == eblkno) &&
574 (i == lsp->ls_comp_index_sz - 1)) {
575 cmpbytes = lsp->ls_vp_comp_size -
576 lsp->ls_comp_seg_index[i];
577 } else {
578 cmpbytes = lsp->ls_comp_seg_index[i + 1] -
579 lsp->ls_comp_seg_index[i];
580 }
581
582 /*
583 * The first byte in a compressed segment is a flag
584 * that indicates whether is this segment is
585 * compressed at all
586 */
587 if (*cmpbuf == UNCOMPRESSED) {
588 bcopy((cmpbuf + SEGHDR), uncompressed_seg,
589 (cmpbytes - SEGHDR));
590 } else {
591 seglen = lsp->ls_uncomp_seg_sz;
592
593 if (li->l_decompress((cmpbuf + SEGHDR),
594 (cmpbytes - SEGHDR), uncompressed_seg,
595 &seglen, li->l_level) != 0) {
596 error = EIO;
597 goto done;
598 }
599 }
600
601 /*
602 * Determine how much uncompressed data we
603 * have to copy and copy it
604 */
605 xfersize = lsp->ls_uncomp_seg_sz - sblkoff;
606 if (i == eblkno) {
607 if (i == (lsp->ls_comp_index_sz - 1))
608 xfersize -= (lsp->ls_uncomp_last_seg_sz
609 - eblkoff);
610 else
611 xfersize -=
612 (lsp->ls_uncomp_seg_sz - eblkoff);
613 }
614
615 bcopy((uncompressed_seg + sblkoff), bufaddr, xfersize);
616
617 cmpbuf += cmpbytes;
618 bufaddr += xfersize;
619 bp->b_resid -= xfersize;
620 sblkoff = 0;
621
622 if (bp->b_resid == 0)
623 break;
624 }
625 } else {
626 ssize_t resid;
627 enum uio_rw rw;
628
629 if (bp->b_flags & B_READ)
630 rw = UIO_READ;
631 else
632 rw = UIO_WRITE;
633 error = vn_rdwr(rw, lsp->ls_vp, bufaddr, bp->b_bcount,
634 offset, UIO_SYSSPACE, 0, RLIM64_INFINITY, kcred, &resid);
635 bp->b_resid = resid;
636 }
637
638 done:
639 if (compressed_seg != NULL)
640 kmem_free(compressed_seg, comp_data_sz);
641 if (uncompressed_seg != NULL)
642 kmem_free(uncompressed_seg, lsp->ls_uncomp_seg_sz);
643
644 if (lsp->ls_kstat) {
645 size_t n_done = bp->b_bcount - bp->b_resid;
646 kstat_io_t *kioptr;
647
648 mutex_enter(lsp->ls_kstat->ks_lock);
649 kioptr = KSTAT_IO_PTR(lsp->ls_kstat);
650 if (bp->b_flags & B_READ) {
651 kioptr->nread += n_done;
652 kioptr->reads++;
653 } else {
654 kioptr->nwritten += n_done;
655 kioptr->writes++;
656 }
657 kstat_runq_exit(kioptr);
658 mutex_exit(lsp->ls_kstat->ks_lock);
659 }
660
661 mutex_enter(&lsp->ls_vp_lock);
662 if (--lsp->ls_vp_iocount == 0)
663 cv_broadcast(&lsp->ls_vp_cv);
664 mutex_exit(&lsp->ls_vp_lock);
665
666 bioerror(bp, error);
667 biodone(bp);
668 }
669
670 static int
671 lofi_strategy(struct buf *bp)
672 {
673 struct lofi_state *lsp;
674 offset_t offset;
675
676 /*
677 * We cannot just do I/O here, because the current thread
678 * _might_ end up back in here because the underlying filesystem
679 * wants a buffer, which eventually gets into bio_recycle and
680 * might call into lofi to write out a delayed-write buffer.
681 * This is bad if the filesystem above lofi is the same as below.
682 *
683 * We could come up with a complex strategy using threads to
684 * do the I/O asynchronously, or we could use task queues. task
685 * queues were incredibly easy so they win.
686 */
687 lsp = ddi_get_soft_state(lofi_statep, getminor(bp->b_edev));
688 mutex_enter(&lsp->ls_vp_lock);
689 if (lsp->ls_vp == NULL || lsp->ls_vp_closereq) {
690 bioerror(bp, EIO);
691 biodone(bp);
692 mutex_exit(&lsp->ls_vp_lock);
693 return (0);
694 }
695
696 offset = bp->b_lblkno * DEV_BSIZE; /* offset within file */
697 if (offset == lsp->ls_vp_size) {
698 /* EOF */
699 if ((bp->b_flags & B_READ) != 0) {
700 bp->b_resid = bp->b_bcount;
701 bioerror(bp, 0);
702 } else {
703 /* writes should fail */
704 bioerror(bp, ENXIO);
705 }
706 biodone(bp);
707 mutex_exit(&lsp->ls_vp_lock);
708 return (0);
709 }
710 if (offset > lsp->ls_vp_size) {
711 bioerror(bp, ENXIO);
712 biodone(bp);
713 mutex_exit(&lsp->ls_vp_lock);
714 return (0);
715 }
716 lsp->ls_vp_iocount++;
717 mutex_exit(&lsp->ls_vp_lock);
718
719 if (lsp->ls_kstat) {
720 mutex_enter(lsp->ls_kstat->ks_lock);
721 kstat_waitq_enter(KSTAT_IO_PTR(lsp->ls_kstat));
722 mutex_exit(lsp->ls_kstat->ks_lock);
723 }
724 (void) taskq_dispatch(lsp->ls_taskq, lofi_strategy_task, bp, KM_SLEEP);
725 return (0);
726 }
727
728 /*ARGSUSED2*/
729 static int
730 lofi_read(dev_t dev, struct uio *uio, struct cred *credp)
731 {
732 if (getminor(dev) == 0)
733 return (EINVAL);
734 return (physio(lofi_strategy, NULL, dev, B_READ, minphys, uio));
735 }
736
737 /*ARGSUSED2*/
738 static int
739 lofi_write(dev_t dev, struct uio *uio, struct cred *credp)
740 {
741 if (getminor(dev) == 0)
742 return (EINVAL);
743 return (physio(lofi_strategy, NULL, dev, B_WRITE, minphys, uio));
744 }
745
746 /*ARGSUSED2*/
747 static int
748 lofi_aread(dev_t dev, struct aio_req *aio, struct cred *credp)
749 {
750 if (getminor(dev) == 0)
751 return (EINVAL);
752 return (aphysio(lofi_strategy, anocancel, dev, B_READ, minphys, aio));
753 }
754
755 /*ARGSUSED2*/
756 static int
757 lofi_awrite(dev_t dev, struct aio_req *aio, struct cred *credp)
758 {
759 if (getminor(dev) == 0)
760 return (EINVAL);
761 return (aphysio(lofi_strategy, anocancel, dev, B_WRITE, minphys, aio));
762 }
763
764 /*ARGSUSED*/
765 static int
766 lofi_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
767 {
768 switch (infocmd) {
769 case DDI_INFO_DEVT2DEVINFO:
770 *result = lofi_dip;
771 return (DDI_SUCCESS);
772 case DDI_INFO_DEVT2INSTANCE:
773 *result = 0;
774 return (DDI_SUCCESS);
775 }
776 return (DDI_FAILURE);
777 }
778
779 static int
780 lofi_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
781 {
782 int error;
783
784 if (cmd != DDI_ATTACH)
785 return (DDI_FAILURE);
786 error = ddi_soft_state_zalloc(lofi_statep, 0);
787 if (error == DDI_FAILURE) {
788 return (DDI_FAILURE);
789 }
790 error = ddi_create_minor_node(dip, LOFI_CTL_NODE, S_IFCHR, 0,
791 DDI_PSEUDO, NULL);
792 if (error == DDI_FAILURE) {
793 ddi_soft_state_free(lofi_statep, 0);
794 return (DDI_FAILURE);
795 }
796 /* driver handles kernel-issued IOCTLs */
797 if (ddi_prop_create(DDI_DEV_T_NONE, dip, DDI_PROP_CANSLEEP,
798 DDI_KERNEL_IOCTL, NULL, 0) != DDI_PROP_SUCCESS) {
799 ddi_remove_minor_node(dip, NULL);
800 ddi_soft_state_free(lofi_statep, 0);
801 return (DDI_FAILURE);
802 }
803 lofi_dip = dip;
804 ddi_report_dev(dip);
805 return (DDI_SUCCESS);
806 }
807
808 static int
809 lofi_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
810 {
811 if (cmd != DDI_DETACH)
812 return (DDI_FAILURE);
813 if (lofi_busy())
814 return (DDI_FAILURE);
815 lofi_dip = NULL;
816 ddi_remove_minor_node(dip, NULL);
817 ddi_prop_remove_all(dip);
818 ddi_soft_state_free(lofi_statep, 0);
819 return (DDI_SUCCESS);
820 }
821
822 /*
823 * These two just simplify the rest of the ioctls that need to copyin/out
824 * the lofi_ioctl structure.
825 */
826 struct lofi_ioctl *
827 copy_in_lofi_ioctl(const struct lofi_ioctl *ulip, int flag)
828 {
829 struct lofi_ioctl *klip;
830 int error;
831
832 klip = kmem_alloc(sizeof (struct lofi_ioctl), KM_SLEEP);
833 error = ddi_copyin(ulip, klip, sizeof (struct lofi_ioctl), flag);
834 if (error) {
835 kmem_free(klip, sizeof (struct lofi_ioctl));
836 return (NULL);
837 }
838
839 /* make sure filename is always null-terminated */
840 klip->li_filename[MAXPATHLEN - 1] = '\0';
841
842 /* validate minor number */
843 if (klip->li_minor > lofi_max_files) {
844 kmem_free(klip, sizeof (struct lofi_ioctl));
845 return (NULL);
846 }
847 return (klip);
848 }
849
850 int
851 copy_out_lofi_ioctl(const struct lofi_ioctl *klip, struct lofi_ioctl *ulip,
852 int flag)
853 {
854 int error;
855
856 error = ddi_copyout(klip, ulip, sizeof (struct lofi_ioctl), flag);
857 if (error)
858 return (EFAULT);
859 return (0);
860 }
861
862 void
863 free_lofi_ioctl(struct lofi_ioctl *klip)
864 {
865 kmem_free(klip, sizeof (struct lofi_ioctl));
866 }
867
868 /*
869 * Return the minor number 'filename' is mapped to, if it is.
870 */
871 static int
872 file_to_minor(char *filename)
873 {
874 minor_t minor;
875 struct lofi_state *lsp;
876
877 ASSERT(mutex_owned(&lofi_lock));
878 for (minor = 1; minor <= lofi_max_files; minor++) {
879 lsp = ddi_get_soft_state(lofi_statep, minor);
880 if (lsp == NULL)
881 continue;
882 if (strcmp(lsp->ls_filename, filename) == 0)
883 return (minor);
884 }
885 return (0);
886 }
887
888 /*
889 * lofiadm does some validation, but since Joe Random (or crashme) could
890 * do our ioctls, we need to do some validation too.
891 */
892 static int
893 valid_filename(const char *filename)
894 {
895 static char *blkprefix = "/dev/" LOFI_BLOCK_NAME "/";
896 static char *charprefix = "/dev/" LOFI_CHAR_NAME "/";
897
898 /* must be absolute path */
899 if (filename[0] != '/')
900 return (0);
901 /* must not be lofi */
902 if (strncmp(filename, blkprefix, strlen(blkprefix)) == 0)
903 return (0);
904 if (strncmp(filename, charprefix, strlen(charprefix)) == 0)
905 return (0);
906 return (1);
907 }
908
909 /*
910 * Fakes up a disk geometry, and one big partition, based on the size
911 * of the file. This is needed because we allow newfs'ing the device,
912 * and newfs will do several disk ioctls to figure out the geometry and
913 * partition information. It uses that information to determine the parameters
914 * to pass to mkfs. Geometry is pretty much irrelevant these days, but we
915 * have to support it.
916 */
917 static void
918 fake_disk_geometry(struct lofi_state *lsp)
919 {
920 /* dk_geom - see dkio(7I) */
921 /*
922 * dkg_ncyl _could_ be set to one here (one big cylinder with gobs
923 * of sectors), but that breaks programs like fdisk which want to
924 * partition a disk by cylinder. With one cylinder, you can't create
925 * an fdisk partition and put pcfs on it for testing (hard to pick
926 * a number between one and one).
927 *
928 * The cheezy floppy test is an attempt to not have too few cylinders
929 * for a small file, or so many on a big file that you waste space
930 * for backup superblocks or cylinder group structures.
931 */
932 if (lsp->ls_vp_size < (2 * 1024 * 1024)) /* floppy? */
933 lsp->ls_dkg.dkg_ncyl = lsp->ls_vp_size / (100 * 1024);
934 else
935 lsp->ls_dkg.dkg_ncyl = lsp->ls_vp_size / (300 * 1024);
936 /* in case file file is < 100k */
937 if (lsp->ls_dkg.dkg_ncyl == 0)
938 lsp->ls_dkg.dkg_ncyl = 1;
939 lsp->ls_dkg.dkg_acyl = 0;
940 lsp->ls_dkg.dkg_bcyl = 0;
941 lsp->ls_dkg.dkg_nhead = 1;
942 lsp->ls_dkg.dkg_obs1 = 0;
943 lsp->ls_dkg.dkg_intrlv = 0;
944 lsp->ls_dkg.dkg_obs2 = 0;
945 lsp->ls_dkg.dkg_obs3 = 0;
946 lsp->ls_dkg.dkg_apc = 0;
947 lsp->ls_dkg.dkg_rpm = 7200;
948 lsp->ls_dkg.dkg_pcyl = lsp->ls_dkg.dkg_ncyl + lsp->ls_dkg.dkg_acyl;
949 lsp->ls_dkg.dkg_nsect = lsp->ls_vp_size /
950 (DEV_BSIZE * lsp->ls_dkg.dkg_ncyl);
951 lsp->ls_dkg.dkg_write_reinstruct = 0;
952 lsp->ls_dkg.dkg_read_reinstruct = 0;
953
954 /* vtoc - see dkio(7I) */
955 bzero(&lsp->ls_vtoc, sizeof (struct vtoc));
956 lsp->ls_vtoc.v_sanity = VTOC_SANE;
957 lsp->ls_vtoc.v_version = V_VERSION;
958 bcopy(LOFI_DRIVER_NAME, lsp->ls_vtoc.v_volume, 7);
959 lsp->ls_vtoc.v_sectorsz = DEV_BSIZE;
960 lsp->ls_vtoc.v_nparts = 1;
961 lsp->ls_vtoc.v_part[0].p_tag = V_UNASSIGNED;
962
963 /*
964 * A compressed file is read-only, other files can
965 * be read-write
966 */
967 if (lsp->ls_uncomp_seg_sz > 0) {
968 lsp->ls_vtoc.v_part[0].p_flag = V_UNMNT | V_RONLY;
969 } else {
970 lsp->ls_vtoc.v_part[0].p_flag = V_UNMNT;
971 }
972 lsp->ls_vtoc.v_part[0].p_start = (daddr_t)0;
973 /*
974 * The partition size cannot just be the number of sectors, because
975 * that might not end on a cylinder boundary. And if that's the case,
976 * newfs/mkfs will print a scary warning. So just figure the size
977 * based on the number of cylinders and sectors/cylinder.
978 */
979 lsp->ls_vtoc.v_part[0].p_size = lsp->ls_dkg.dkg_pcyl *
980 lsp->ls_dkg.dkg_nsect * lsp->ls_dkg.dkg_nhead;
981
982 /* dk_cinfo - see dkio(7I) */
983 bzero(&lsp->ls_ci, sizeof (struct dk_cinfo));
984 (void) strcpy(lsp->ls_ci.dki_cname, LOFI_DRIVER_NAME);
985 lsp->ls_ci.dki_ctype = DKC_MD;
986 lsp->ls_ci.dki_flags = 0;
987 lsp->ls_ci.dki_cnum = 0;
988 lsp->ls_ci.dki_addr = 0;
989 lsp->ls_ci.dki_space = 0;
990 lsp->ls_ci.dki_prio = 0;
991 lsp->ls_ci.dki_vec = 0;
992 (void) strcpy(lsp->ls_ci.dki_dname, LOFI_DRIVER_NAME);
993 lsp->ls_ci.dki_unit = 0;
994 lsp->ls_ci.dki_slave = 0;
995 lsp->ls_ci.dki_partition = 0;
996 /*
997 * newfs uses this to set maxcontig. Must not be < 16, or it
998 * will be 0 when newfs multiplies it by DEV_BSIZE and divides
999 * it by the block size. Then tunefs doesn't work because
1000 * maxcontig is 0.
1001 */
1002 lsp->ls_ci.dki_maxtransfer = 16;
1003 }
1004
1005 /*
1006 * map in a compressed file
1007 *
1008 * Read in the header and the index that follows.
1009 *
1010 * The header is as follows -
1011 *
1012 * Signature (name of the compression algorithm)
1013 * Compression segment size (a multiple of 512)
1014 * Number of index entries
1015 * Size of the last block
1016 * The array containing the index entries
1017 *
1018 * The header information is always stored in
1019 * network byte order on disk.
1020 */
1021 static int
1022 lofi_map_compressed_file(struct lofi_state *lsp, char *buf)
1023 {
1024 uint32_t index_sz, header_len, i;
1025 ssize_t resid;
1026 enum uio_rw rw;
1027 char *tbuf = buf;
1028 int error;
1029
1030 /* The signature has already been read */
1031 tbuf += lsp->ls_comp_algorithm_len;
1032 bcopy(tbuf, &(lsp->ls_uncomp_seg_sz), sizeof (lsp->ls_uncomp_seg_sz));
1033 lsp->ls_uncomp_seg_sz = ntohl(lsp->ls_uncomp_seg_sz);
1034
1035 /*
1036 * The compressed segment size must be a power of 2
1037 */
1038 if (lsp->ls_uncomp_seg_sz % 2)
1039 return (EINVAL);
1040
1041 for (i = 0; !((lsp->ls_uncomp_seg_sz >> i) & 1); i++)
1042 ;
1043
1044 lsp->ls_comp_seg_shift = i;
1045
1046 tbuf += sizeof (lsp->ls_uncomp_seg_sz);
1047 bcopy(tbuf, &(lsp->ls_comp_index_sz), sizeof (lsp->ls_comp_index_sz));
1048 lsp->ls_comp_index_sz = ntohl(lsp->ls_comp_index_sz);
1049
1050 tbuf += sizeof (lsp->ls_comp_index_sz);
1051 bcopy(tbuf, &(lsp->ls_uncomp_last_seg_sz),
1052 sizeof (lsp->ls_uncomp_last_seg_sz));
1053 lsp->ls_uncomp_last_seg_sz = ntohl(lsp->ls_uncomp_last_seg_sz);
1054
1055 /*
1056 * Compute the total size of the uncompressed data
1057 * for use in fake_disk_geometry and other calculations.
1058 * Disk geometry has to be faked with respect to the
1059 * actual uncompressed data size rather than the
1060 * compressed file size.
1061 */
1062 /* XXX '2' shouldn't subtracted here - should be '1' */
1063 lsp->ls_vp_size = (lsp->ls_comp_index_sz - 2) * lsp->ls_uncomp_seg_sz
1064 + lsp->ls_uncomp_last_seg_sz;
1065
1066 /*
1067 * Index size is rounded up to a 512 byte boundary for ease
1068 * of segmapping
1069 */
1070 index_sz = sizeof (lsp->ls_comp_seg_index) * lsp->ls_comp_index_sz;
1071 header_len = lsp->ls_comp_algorithm_len +
1072 sizeof (lsp->ls_uncomp_seg_sz) +
1073 sizeof (lsp->ls_comp_index_sz) +
1074 sizeof (lsp->ls_uncomp_last_seg_sz);
1075 lsp->ls_comp_offbase = header_len + index_sz;
1076
1077 index_sz += header_len;
1078 index_sz = roundup(index_sz, DEV_BSIZE);
1079
1080 lsp->ls_comp_index_data = kmem_alloc(index_sz, KM_SLEEP);
1081 lsp->ls_comp_index_data_sz = index_sz;
1082
1083 /*
1084 * Read in the index -- this has a side-effect
1085 * of reading in the header as well
1086 */
1087 rw = UIO_READ;
1088 error = vn_rdwr(rw, lsp->ls_vp, lsp->ls_comp_index_data, index_sz,
1089 0, UIO_SYSSPACE, 0, RLIM64_INFINITY, kcred, &resid);
1090
1091 if (error != 0)
1092 return (error);
1093
1094 /* Skip the header, this is where the index really begins */
1095 lsp->ls_comp_seg_index =
1096 /*LINTED*/
1097 (uint64_t *)(lsp->ls_comp_index_data + header_len);
1098
1099 /* Now map the index into memory */
1100 for (i = 0; i < lsp->ls_comp_index_sz; i++)
1101 lsp->ls_comp_seg_index[i] = lsp->ls_comp_offbase +
1102 lsp->ls_comp_seg_index[i];
1103
1104 return (error);
1105 }
1106
1107 /*
1108 * Check to see if the passed in signature is a valid
1109 * one. If it is valid, return the index into
1110 * lofi_compress_table.
1111 *
1112 * Return -1 if it is invalid
1113 */
1114 static int lofi_compress_select(char *signature)
1115 {
1116 int i;
1117
1118 for (i = 0; i < LOFI_COMPRESS_FUNCTIONS; i++) {
1119 if (strcmp(lofi_compress_table[i].l_name, signature) == 0)
1120 return (i);
1121 }
1122
1123 return (-1);
1124 }
1125
1126 /*
1127 * map a file to a minor number. Return the minor number.
1128 */
1129 static int
1130 lofi_map_file(dev_t dev, struct lofi_ioctl *ulip, int pickminor,
1131 int *rvalp, struct cred *credp, int ioctl_flag)
1132 {
1133 minor_t newminor;
1134 struct lofi_state *lsp;
1135 struct lofi_ioctl *klip;
1136 int error;
1137 struct vnode *vp;
1138 int64_t Nblocks_prop_val;
1139 int64_t Size_prop_val;
1140 int compress_index;
1141 vattr_t vattr;
1142 int flag;
1143 enum vtype v_type;
1144 int zalloced = 0;
1145 dev_t newdev;
1146 char namebuf[50];
1147 char buf[DEV_BSIZE];
1148 char *tbuf;
1149 ssize_t resid;
1150 enum uio_rw rw;
1151
1152 klip = copy_in_lofi_ioctl(ulip, ioctl_flag);
1153 if (klip == NULL)
1154 return (EFAULT);
1155
1156 mutex_enter(&lofi_lock);
1157
1158 if (!valid_filename(klip->li_filename)) {
1159 error = EINVAL;
1160 goto out;
1161 }
1162
1163 if (file_to_minor(klip->li_filename) != 0) {
1164 error = EBUSY;
1165 goto out;
1166 }
1167
1168 if (pickminor) {
1169 /* Find a free one */
1170 for (newminor = 1; newminor <= lofi_max_files; newminor++)
1171 if (ddi_get_soft_state(lofi_statep, newminor) == NULL)
1172 break;
1173 if (newminor >= lofi_max_files) {
1174 error = EAGAIN;
1175 goto out;
1176 }
1177 } else {
1178 newminor = klip->li_minor;
1179 if (ddi_get_soft_state(lofi_statep, newminor) != NULL) {
1180 error = EEXIST;
1181 goto out;
1182 }
1183 }
1184
1185 /* make sure it's valid */
1186 error = lookupname(klip->li_filename, UIO_SYSSPACE, FOLLOW,
1187 NULLVPP, &vp);
1188 if (error) {
1189 goto out;
1190 }
1191 v_type = vp->v_type;
1192 VN_RELE(vp);
1193 if (!V_ISLOFIABLE(v_type)) {
1194 error = EINVAL;
1195 goto out;
1196 }
1197 flag = FREAD | FWRITE | FOFFMAX | FEXCL;
1198 error = vn_open(klip->li_filename, UIO_SYSSPACE, flag, 0, &vp, 0, 0);
1199 if (error) {
1200 /* try read-only */
1201 flag &= ~FWRITE;
1202 error = vn_open(klip->li_filename, UIO_SYSSPACE, flag, 0,
1203 &vp, 0, 0);
1204 if (error) {
1205 goto out;
1206 }
1207 }
1208 vattr.va_mask = AT_SIZE;
1209 error = VOP_GETATTR(vp, &vattr, 0, credp);
1210 if (error) {
1211 goto closeout;
1212 }
1213 /* the file needs to be a multiple of the block size */
1214 if ((vattr.va_size % DEV_BSIZE) != 0) {
1215 error = EINVAL;
1216 goto closeout;
1217 }
1218 newdev = makedevice(getmajor(dev), newminor);
1219 Size_prop_val = vattr.va_size;
1220 if ((ddi_prop_update_int64(newdev, lofi_dip,
1221 SIZE_PROP_NAME, Size_prop_val)) != DDI_PROP_SUCCESS) {
1222 error = EINVAL;
1223 goto closeout;
1224 }
1225 Nblocks_prop_val = vattr.va_size / DEV_BSIZE;
1226 if ((ddi_prop_update_int64(newdev, lofi_dip,
1227 NBLOCKS_PROP_NAME, Nblocks_prop_val)) != DDI_PROP_SUCCESS) {
1228 error = EINVAL;
1229 goto propout;
1230 }
1231 error = ddi_soft_state_zalloc(lofi_statep, newminor);
1232 if (error == DDI_FAILURE) {
1233 error = ENOMEM;
1234 goto propout;
1235 }
1236 zalloced = 1;
1237 (void) snprintf(namebuf, sizeof (namebuf), "%d", newminor);
1238 (void) ddi_create_minor_node(lofi_dip, namebuf, S_IFBLK, newminor,
1239 DDI_PSEUDO, NULL);
1240 if (error != DDI_SUCCESS) {
1241 error = ENXIO;
1242 goto propout;
1243 }
1244 (void) snprintf(namebuf, sizeof (namebuf), "%d,raw", newminor);
1245 error = ddi_create_minor_node(lofi_dip, namebuf, S_IFCHR, newminor,
1246 DDI_PSEUDO, NULL);
1247 if (error != DDI_SUCCESS) {
1248 /* remove block node */
1249 (void) snprintf(namebuf, sizeof (namebuf), "%d", newminor);
1250 ddi_remove_minor_node(lofi_dip, namebuf);
1251 error = ENXIO;
1252 goto propout;
1253 }
1254 lsp = ddi_get_soft_state(lofi_statep, newminor);
1255 lsp->ls_filename_sz = strlen(klip->li_filename) + 1;
1256 lsp->ls_filename = kmem_alloc(lsp->ls_filename_sz, KM_SLEEP);
1257 (void) snprintf(namebuf, sizeof (namebuf), "%s_taskq_%d",
1258 LOFI_DRIVER_NAME, newminor);
1259 lsp->ls_taskq = taskq_create(namebuf, lofi_taskq_nthreads,
1260 minclsyspri, 1, lofi_taskq_maxalloc, 0);
1261 lsp->ls_kstat = kstat_create(LOFI_DRIVER_NAME, newminor,
1262 NULL, "disk", KSTAT_TYPE_IO, 1, 0);
1263 if (lsp->ls_kstat) {
1264 mutex_init(&lsp->ls_kstat_lock, NULL, MUTEX_DRIVER, NULL);
1265 lsp->ls_kstat->ks_lock = &lsp->ls_kstat_lock;
1266 kstat_install(lsp->ls_kstat);
1267 }
1268 cv_init(&lsp->ls_vp_cv, NULL, CV_DRIVER, NULL);
1269 mutex_init(&lsp->ls_vp_lock, NULL, MUTEX_DRIVER, NULL);
1270
1271 /*
1272 * save open mode so file can be closed properly and vnode counts
1273 * updated correctly.
1274 */
1275 lsp->ls_openflag = flag;
1276
1277 /*
1278 * Try to handle stacked lofs vnodes.
1279 */
1280 if (vp->v_type == VREG) {
1281 if (VOP_REALVP(vp, &lsp->ls_vp) != 0) {
1282 lsp->ls_vp = vp;
1283 } else {
1284 /*
1285 * Even though vp was obtained via vn_open(), we
1286 * can't call vn_close() on it, since lofs will
1287 * pass the VOP_CLOSE() on down to the realvp
1288 * (which we are about to use). Hence we merely
1289 * drop the reference to the lofs vnode and hold
1290 * the realvp so things behave as if we've
1291 * opened the realvp without any interaction
1292 * with lofs.
1293 */
1294 VN_HOLD(lsp->ls_vp);
1295 VN_RELE(vp);
1296 }
1297 } else {
1298 lsp->ls_vp = vp;
1299 }
1300 lsp->ls_vp_size = vattr.va_size;
1301 (void) strcpy(lsp->ls_filename, klip->li_filename);
1302 if (rvalp)
1303 *rvalp = (int)newminor;
1304 klip->li_minor = newminor;
1305
1306 /*
1307 * Read the file signature to check if it is compressed.
1308 * 'rw' is set to read since only reads are allowed to
1309 * a compressed file.
1310 */
1311 rw = UIO_READ;
1312 error = vn_rdwr(rw, lsp->ls_vp, buf, DEV_BSIZE, 0, UIO_SYSSPACE,
1313 0, RLIM64_INFINITY, kcred, &resid);
1314
1315 if (error != 0)
1316 goto propout;
1317
1318 tbuf = buf;
1319 lsp->ls_uncomp_seg_sz = 0;
1320 lsp->ls_vp_comp_size = lsp->ls_vp_size;
1321 lsp->ls_comp_algorithm_len = 0;
1322
1323 compress_index = lofi_compress_select(tbuf);
1324 if (compress_index != -1) {
1325 lsp->ls_comp_algorithm_index = compress_index;
1326 lsp->ls_comp_algorithm_len =
1327 strlen(lofi_compress_table[compress_index].l_name);
1328 error = lofi_map_compressed_file(lsp, buf);
1329 if (error != 0)
1330 goto propout;
1331
1332 /* update DDI properties */
1333 Size_prop_val = lsp->ls_vp_size;
1334 if ((ddi_prop_update_int64(newdev, lofi_dip, SIZE_PROP_NAME,
1335 Size_prop_val)) != DDI_PROP_SUCCESS) {
1336 error = EINVAL;
1337 goto propout;
1338 }
1339
1340 Nblocks_prop_val = lsp->ls_vp_size / DEV_BSIZE;
1341 if ((ddi_prop_update_int64(newdev, lofi_dip, NBLOCKS_PROP_NAME,
1342 Nblocks_prop_val)) != DDI_PROP_SUCCESS) {
1343 error = EINVAL;
1344 goto propout;
1345 }
1346 }
1347
1348 fake_disk_geometry(lsp);
1349 mutex_exit(&lofi_lock);
1350 (void) copy_out_lofi_ioctl(klip, ulip, ioctl_flag);
1351 free_lofi_ioctl(klip);
1352 return (0);
1353
1354 propout:
1355 (void) ddi_prop_remove(newdev, lofi_dip, SIZE_PROP_NAME);
1356 (void) ddi_prop_remove(newdev, lofi_dip, NBLOCKS_PROP_NAME);
1357 closeout:
1358 (void) VOP_CLOSE(vp, flag, 1, 0, credp);
1359 VN_RELE(vp);
1360 out:
1361 if (zalloced)
1362 ddi_soft_state_free(lofi_statep, newminor);
1363 mutex_exit(&lofi_lock);
1364 free_lofi_ioctl(klip);
1365 return (error);
1366 }
1367
1368 /*
1369 * unmap a file.
1370 */
1371 static int
1372 lofi_unmap_file(dev_t dev, struct lofi_ioctl *ulip, int byfilename,
1373 struct cred *credp, int ioctl_flag)
1374 {
1375 struct lofi_state *lsp;
1376 struct lofi_ioctl *klip;
1377 minor_t minor;
1378
1379 klip = copy_in_lofi_ioctl(ulip, ioctl_flag);
1380 if (klip == NULL)
1381 return (EFAULT);
1382
1383 mutex_enter(&lofi_lock);
1384 if (byfilename) {
1385 minor = file_to_minor(klip->li_filename);
1386 } else {
1387 minor = klip->li_minor;
1388 }
1389 if (minor == 0) {
1390 mutex_exit(&lofi_lock);
1391 free_lofi_ioctl(klip);
1392 return (ENXIO);
1393 }
1394 lsp = ddi_get_soft_state(lofi_statep, minor);
1395 if (lsp == NULL || lsp->ls_vp == NULL) {
1396 mutex_exit(&lofi_lock);
1397 free_lofi_ioctl(klip);
1398 return (ENXIO);
1399 }
1400
1401 if (is_opened(lsp)) {
1402 /*
1403 * If the 'force' flag is set, then we forcibly close the
1404 * underlying file. Subsequent operations will fail, and the
1405 * DKIOCSTATE ioctl will return DKIO_DEV_GONE. When the device
1406 * is last closed, the device will be cleaned up appropriately.
1407 *
1408 * This is complicated by the fact that we may have outstanding
1409 * dispatched I/Os. Rather than having a single mutex to
1410 * serialize all I/O, we keep a count of the number of
1411 * outstanding I/O requests, as well as a flag to indicate that
1412 * no new I/Os should be dispatched. We set the flag, wait for
1413 * the number of outstanding I/Os to reach 0, and then close the
1414 * underlying vnode.
1415 */
1416 if (klip->li_force) {
1417 mutex_enter(&lsp->ls_vp_lock);
1418 lsp->ls_vp_closereq = B_TRUE;
1419 while (lsp->ls_vp_iocount > 0)
1420 cv_wait(&lsp->ls_vp_cv, &lsp->ls_vp_lock);
1421 (void) VOP_CLOSE(lsp->ls_vp, lsp->ls_openflag, 1, 0,
1422 credp);
1423 VN_RELE(lsp->ls_vp);
1424 lsp->ls_vp = NULL;
1425 cv_broadcast(&lsp->ls_vp_cv);
1426 mutex_exit(&lsp->ls_vp_lock);
1427 mutex_exit(&lofi_lock);
1428 klip->li_minor = minor;
1429 (void) copy_out_lofi_ioctl(klip, ulip, ioctl_flag);
1430 free_lofi_ioctl(klip);
1431 return (0);
1432 }
1433 mutex_exit(&lofi_lock);
1434 free_lofi_ioctl(klip);
1435 return (EBUSY);
1436 }
1437
1438 if (lsp->ls_uncomp_seg_sz > 0) {
1439 kmem_free(lsp->ls_comp_index_data, lsp->ls_comp_index_data_sz);
1440 lsp->ls_uncomp_seg_sz = 0;
1441 }
1442
1443 lofi_free_handle(dev, minor, lsp, credp);
1444
1445 klip->li_minor = minor;
1446 mutex_exit(&lofi_lock);
1447 (void) copy_out_lofi_ioctl(klip, ulip, ioctl_flag);
1448 free_lofi_ioctl(klip);
1449 return (0);
1450 }
1451
1452 /*
1453 * get the filename given the minor number, or the minor number given
1454 * the name.
1455 */
1456 /*ARGSUSED*/
1457 static int
1458 lofi_get_info(dev_t dev, struct lofi_ioctl *ulip, int which,
1459 struct cred *credp, int ioctl_flag)
1460 {
1461 struct lofi_state *lsp;
1462 struct lofi_ioctl *klip;
1463 int error;
1464 minor_t minor;
1465
1466 klip = copy_in_lofi_ioctl(ulip, ioctl_flag);
1467 if (klip == NULL)
1468 return (EFAULT);
1469
1470 switch (which) {
1471 case LOFI_GET_FILENAME:
1472 minor = klip->li_minor;
1473 if (minor == 0) {
1474 free_lofi_ioctl(klip);
1475 return (EINVAL);
1476 }
1477
1478 mutex_enter(&lofi_lock);
1479 lsp = ddi_get_soft_state(lofi_statep, minor);
1480 if (lsp == NULL) {
1481 mutex_exit(&lofi_lock);
1482 free_lofi_ioctl(klip);
1483 return (ENXIO);
1484 }
1485 (void) strcpy(klip->li_filename, lsp->ls_filename);
1486 if (lsp->ls_comp_algorithm_len == 0)
1487 klip->li_algorithm[0] = '\0';
1488 else
1489 (void) strlcpy(klip->li_algorithm, lofi_compress_table[
1490 lsp->ls_comp_algorithm_index].l_name,
1491 lsp->ls_comp_algorithm_len + 1);
1492 mutex_exit(&lofi_lock);
1493 error = copy_out_lofi_ioctl(klip, ulip, ioctl_flag);
1494 free_lofi_ioctl(klip);
1495 return (error);
1496 case LOFI_GET_MINOR:
1497 mutex_enter(&lofi_lock);
1498 klip->li_minor = file_to_minor(klip->li_filename);
1499 mutex_exit(&lofi_lock);
1500 if (klip->li_minor == 0) {
1501 free_lofi_ioctl(klip);
1502 return (ENOENT);
1503 }
1504 error = copy_out_lofi_ioctl(klip, ulip, ioctl_flag);
1505 free_lofi_ioctl(klip);
1506 return (error);
1507 case LOFI_CHECK_COMPRESSED:
1508 mutex_enter(&lofi_lock);
1509 klip->li_minor = file_to_minor(klip->li_filename);
1510 mutex_exit(&lofi_lock);
1511 if (klip->li_minor == 0) {
1512 free_lofi_ioctl(klip);
1513 return (ENOENT);
1514 }
1515 mutex_enter(&lofi_lock);
1516 lsp = ddi_get_soft_state(lofi_statep, klip->li_minor);
1517 if (lsp == NULL) {
1518 mutex_exit(&lofi_lock);
1519 free_lofi_ioctl(klip);
1520 return (ENXIO);
1521 }
1522 ASSERT(strcmp(klip->li_filename, lsp->ls_filename) == 0);
1523
1524 if (lsp->ls_comp_algorithm_len == 0)
1525 klip->li_algorithm[0] = '\0';
1526 else
1527 (void) strlcpy(klip->li_algorithm, lofi_compress_table[
1528 lsp->ls_comp_algorithm_index].l_name,
1529 lsp->ls_comp_algorithm_len + 1);
1530
1531 mutex_exit(&lofi_lock);
1532 error = copy_out_lofi_ioctl(klip, ulip, ioctl_flag);
1533 free_lofi_ioctl(klip);
1534 return (error);
1535 default:
1536 free_lofi_ioctl(klip);
1537 return (EINVAL);
1538 }
1539
1540 }
1541
1542 static int
1543 lofi_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *credp,
1544 int *rvalp)
1545 {
1546 int error;
1547 enum dkio_state dkstate;
1548 struct lofi_state *lsp;
1549 minor_t minor;
1550
1551 #ifdef lint
1552 credp = credp;
1553 #endif
1554
1555 minor = getminor(dev);
1556 /* lofi ioctls only apply to the master device */
1557 if (minor == 0) {
1558 struct lofi_ioctl *lip = (struct lofi_ioctl *)arg;
1559
1560 /*
1561 * the query command only need read-access - i.e., normal
1562 * users are allowed to do those on the ctl device as
1563 * long as they can open it read-only.
1564 */
1565 switch (cmd) {
1566 case LOFI_MAP_FILE:
1567 if ((flag & FWRITE) == 0)
1568 return (EPERM);
1569 return (lofi_map_file(dev, lip, 1, rvalp, credp, flag));
1570 case LOFI_MAP_FILE_MINOR:
1571 if ((flag & FWRITE) == 0)
1572 return (EPERM);
1573 return (lofi_map_file(dev, lip, 0, rvalp, credp, flag));
1574 case LOFI_UNMAP_FILE:
1575 if ((flag & FWRITE) == 0)
1576 return (EPERM);
1577 return (lofi_unmap_file(dev, lip, 1, credp, flag));
1578 case LOFI_UNMAP_FILE_MINOR:
1579 if ((flag & FWRITE) == 0)
1580 return (EPERM);
1581 return (lofi_unmap_file(dev, lip, 0, credp, flag));
1582 case LOFI_GET_FILENAME:
1583 return (lofi_get_info(dev, lip, LOFI_GET_FILENAME,
1584 credp, flag));
1585 case LOFI_GET_MINOR:
1586 return (lofi_get_info(dev, lip, LOFI_GET_MINOR,
1587 credp, flag));
1588 case LOFI_GET_MAXMINOR:
1589 error = ddi_copyout(&lofi_max_files, &lip->li_minor,
1590 sizeof (lofi_max_files), flag);
1591 if (error)
1592 return (EFAULT);
1593 return (0);
1594 case LOFI_CHECK_COMPRESSED:
1595 return (lofi_get_info(dev, lip, LOFI_CHECK_COMPRESSED,
1596 credp, flag));
1597 default:
1598 break;
1599 }
1600 }
1601
1602 lsp = ddi_get_soft_state(lofi_statep, minor);
1603 if (lsp == NULL)
1604 return (ENXIO);
1605
1606 /*
1607 * We explicitly allow DKIOCSTATE, but all other ioctls should fail with
1608 * EIO as if the device was no longer present.
1609 */
1610 if (lsp->ls_vp == NULL && cmd != DKIOCSTATE)
1611 return (EIO);
1612
1613 /* these are for faking out utilities like newfs */
1614 switch (cmd) {
1615 case DKIOCGVTOC:
1616 switch (ddi_model_convert_from(flag & FMODELS)) {
1617 case DDI_MODEL_ILP32: {
1618 struct vtoc32 vtoc32;
1619
1620 vtoctovtoc32(lsp->ls_vtoc, vtoc32);
1621 if (ddi_copyout(&vtoc32, (void *)arg,
1622 sizeof (struct vtoc32), flag))
1623 return (EFAULT);
1624 break;
1625 }
1626
1627 case DDI_MODEL_NONE:
1628 if (ddi_copyout(&lsp->ls_vtoc, (void *)arg,
1629 sizeof (struct vtoc), flag))
1630 return (EFAULT);
1631 break;
1632 }
1633 return (0);
1634 case DKIOCINFO:
1635 error = ddi_copyout(&lsp->ls_ci, (void *)arg,
1636 sizeof (struct dk_cinfo), flag);
1637 if (error)
1638 return (EFAULT);
1639 return (0);
1640 case DKIOCG_VIRTGEOM:
1641 case DKIOCG_PHYGEOM:
1642 case DKIOCGGEOM:
1643 error = ddi_copyout(&lsp->ls_dkg, (void *)arg,
1644 sizeof (struct dk_geom), flag);
1645 if (error)
1646 return (EFAULT);
1647 return (0);
1648 case DKIOCSTATE:
1649 /*
1650 * Normally, lofi devices are always in the INSERTED state. If
1651 * a device is forcefully unmapped, then the device transitions
1652 * to the DKIO_DEV_GONE state.
1653 */
1654 if (ddi_copyin((void *)arg, &dkstate, sizeof (dkstate),
1655 flag) != 0)
1656 return (EFAULT);
1657
1658 mutex_enter(&lsp->ls_vp_lock);
1659 while ((dkstate == DKIO_INSERTED && lsp->ls_vp != NULL) ||
1660 (dkstate == DKIO_DEV_GONE && lsp->ls_vp == NULL)) {
1661 /*
1662 * By virtue of having the device open, we know that
1663 * 'lsp' will remain valid when we return.
1664 */
1665 if (!cv_wait_sig(&lsp->ls_vp_cv,
1666 &lsp->ls_vp_lock)) {
1667 mutex_exit(&lsp->ls_vp_lock);
1668 return (EINTR);
1669 }
1670 }
1671
1672 dkstate = (lsp->ls_vp != NULL ? DKIO_INSERTED : DKIO_DEV_GONE);
1673 mutex_exit(&lsp->ls_vp_lock);
1674
1675 if (ddi_copyout(&dkstate, (void *)arg,
1676 sizeof (dkstate), flag) != 0)
1677 return (EFAULT);
1678 return (0);
1679 default:
1680 return (ENOTTY);
1681 }
1682 }
1683
1684 static struct cb_ops lofi_cb_ops = {
1685 lofi_open, /* open */
1686 lofi_close, /* close */
1687 lofi_strategy, /* strategy */
1688 nodev, /* print */
1689 nodev, /* dump */
1690 lofi_read, /* read */
1691 lofi_write, /* write */
1692 lofi_ioctl, /* ioctl */
1693 nodev, /* devmap */
1694 nodev, /* mmap */
1695 nodev, /* segmap */
1696 nochpoll, /* poll */
1697 ddi_prop_op, /* prop_op */
1698 0, /* streamtab */
1699 D_64BIT | D_NEW | D_MP, /* Driver compatibility flag */
1700 CB_REV,
1701 lofi_aread,
1702 lofi_awrite
1703 };
1704
1705 static struct dev_ops lofi_ops = {
1706 DEVO_REV, /* devo_rev, */
1707 0, /* refcnt */
1708 lofi_info, /* info */
1709 nulldev, /* identify */
1710 nulldev, /* probe */
1711 lofi_attach, /* attach */
1712 lofi_detach, /* detach */
1713 nodev, /* reset */
1714 &lofi_cb_ops, /* driver operations */
1715 NULL /* no bus operations */
1716 };
1717
1718 static struct modldrv modldrv = {
1719 &mod_driverops,
1720 "loopback file driver (%I%)",
1721 &lofi_ops,
1722 };
1723
1724 static struct modlinkage modlinkage = {
1725 MODREV_1,
1726 &modldrv,
1727 NULL
1728 };
1729
1730 int
1731 _init(void)
1732 {
1733 int error;
1734
1735 error = ddi_soft_state_init(&lofi_statep,
1736 sizeof (struct lofi_state), 0);
1737 if (error)
1738 return (error);
1739
1740 mutex_init(&lofi_lock, NULL, MUTEX_DRIVER, NULL);
1741 error = mod_install(&modlinkage);
1742 if (error) {
1743 mutex_destroy(&lofi_lock);
1744 ddi_soft_state_fini(&lofi_statep);
1745 }
1746
1747 return (error);
1748 }
1749
1750 int
1751 _fini(void)
1752 {
1753 int error;
1754
1755 if (lofi_busy())
1756 return (EBUSY);
1757
1758 error = mod_remove(&modlinkage);
1759 if (error)
1760 return (error);
1761
1762 mutex_destroy(&lofi_lock);
1763 ddi_soft_state_fini(&lofi_statep);
1764
1765 return (error);
1766 }
1767
1768 int
1769 _info(struct modinfo *modinfop)
1770 {
1771 return (mod_info(&modlinkage, modinfop));
1772 }