xref: /freebsd/sys/geom/uzip/g_uzip.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2004 Max Khon
5  * Copyright (c) 2014 Juniper Networks, Inc.
6  * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 #include "opt_geom.h"
33 #include "opt_zstdio.h"
34 
35 #include <sys/param.h>
36 #include <sys/bio.h>
37 #include <sys/endian.h>
38 #include <sys/errno.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/malloc.h>
43 #include <sys/sysctl.h>
44 #include <sys/systm.h>
45 #include <sys/kthread.h>
46 
47 #include <geom/geom.h>
48 
49 #include <geom/uzip/g_uzip.h>
50 #include <geom/uzip/g_uzip_cloop.h>
51 #include <geom/uzip/g_uzip_softc.h>
52 #include <geom/uzip/g_uzip_dapi.h>
53 #include <geom/uzip/g_uzip_zlib.h>
54 #include <geom/uzip/g_uzip_lzma.h>
55 #ifdef ZSTDIO
56 #include <geom/uzip/g_uzip_zstd.h>
57 #endif
58 #include <geom/uzip/g_uzip_wrkthr.h>
59 
60 MALLOC_DEFINE(M_GEOM_UZIP, "geom_uzip", "GEOM UZIP data structures");
61 
62 FEATURE(geom_uzip, "GEOM read-only compressed disks support");
63 
64 struct g_uzip_blk {
65         uint64_t offset;
66         uint32_t blen;
67         unsigned char last:1;
68         unsigned char padded:1;
69 #define BLEN_UNDEF      UINT32_MAX
70 };
71 
72 #ifndef ABS
73 #define	ABS(a)			((a) < 0 ? -(a) : (a))
74 #endif
75 
76 #define BLK_IN_RANGE(mcn, bcn, ilen)	\
77     (((bcn) != BLEN_UNDEF) && ( \
78 	((ilen) >= 0 && (mcn >= bcn) && (mcn <= ((intmax_t)(bcn) + (ilen)))) || \
79 	((ilen) < 0 && (mcn <= bcn) && (mcn >= ((intmax_t)(bcn) + (ilen)))) \
80     ))
81 
82 #ifdef GEOM_UZIP_DEBUG
83 # define GEOM_UZIP_DBG_DEFAULT	3
84 #else
85 # define GEOM_UZIP_DBG_DEFAULT	0
86 #endif
87 
88 #define	GUZ_DBG_ERR	1
89 #define	GUZ_DBG_INFO	2
90 #define	GUZ_DBG_IO	3
91 #define	GUZ_DBG_TOC	4
92 
93 #define	GUZ_DEV_SUFX	".uzip"
94 #define	GUZ_DEV_NAME(p)	(p GUZ_DEV_SUFX)
95 
96 static char g_uzip_attach_to[MAXPATHLEN] = {"*"};
97 static char g_uzip_noattach_to[MAXPATHLEN] = {GUZ_DEV_NAME("*")};
98 TUNABLE_STR("kern.geom.uzip.attach_to", g_uzip_attach_to,
99     sizeof(g_uzip_attach_to));
100 TUNABLE_STR("kern.geom.uzip.noattach_to", g_uzip_noattach_to,
101     sizeof(g_uzip_noattach_to));
102 
103 SYSCTL_DECL(_kern_geom);
104 SYSCTL_NODE(_kern_geom, OID_AUTO, uzip, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
105     "GEOM_UZIP stuff");
106 static u_int g_uzip_debug = GEOM_UZIP_DBG_DEFAULT;
107 SYSCTL_UINT(_kern_geom_uzip, OID_AUTO, debug, CTLFLAG_RWTUN, &g_uzip_debug, 0,
108     "Debug level (0-4)");
109 static u_int g_uzip_debug_block = BLEN_UNDEF;
110 SYSCTL_UINT(_kern_geom_uzip, OID_AUTO, debug_block, CTLFLAG_RWTUN,
111     &g_uzip_debug_block, 0, "Debug operations around specific cluster#");
112 
113 #define	DPRINTF(lvl, a)		\
114 	if ((lvl) <= g_uzip_debug) { \
115 		printf a; \
116 	}
117 #define	DPRINTF_BLK(lvl, cn, a)	\
118 	if ((lvl) <= g_uzip_debug || \
119 	    BLK_IN_RANGE(cn, g_uzip_debug_block, 8) || \
120 	    BLK_IN_RANGE(cn, g_uzip_debug_block, -8)) { \
121 		printf a; \
122 	}
123 #define	DPRINTF_BRNG(lvl, bcn, ecn, a) \
124 	KASSERT(bcn < ecn, ("DPRINTF_BRNG: invalid range (%ju, %ju)", \
125 	    (uintmax_t)bcn, (uintmax_t)ecn)); \
126 	if (((lvl) <= g_uzip_debug) || \
127 	    BLK_IN_RANGE(g_uzip_debug_block, bcn, \
128 	     (intmax_t)ecn - (intmax_t)bcn)) { \
129 		printf a; \
130 	}
131 
132 #define	UZIP_CLASS_NAME	"UZIP"
133 
134 /*
135  * Maximum allowed valid block size (to prevent foot-shooting)
136  */
137 #define	MAX_BLKSZ	(maxphys)
138 
139 static char CLOOP_MAGIC_START[] = "#!/bin/sh\n";
140 
141 static void g_uzip_read_done(struct bio *bp);
142 static void g_uzip_do(struct g_uzip_softc *, struct bio *bp);
143 
144 static void
145 g_uzip_softc_free(struct g_geom *gp)
146 {
147 	struct g_uzip_softc *sc = gp->softc;
148 
149 	DPRINTF(GUZ_DBG_INFO, ("%s: %d requests, %d cached\n",
150 	    gp->name, sc->req_total, sc->req_cached));
151 
152 	mtx_lock(&sc->queue_mtx);
153 	sc->wrkthr_flags |= GUZ_SHUTDOWN;
154 	wakeup(sc);
155 	while (!(sc->wrkthr_flags & GUZ_EXITING)) {
156 		msleep(sc->procp, &sc->queue_mtx, PRIBIO, "guzfree",
157 		    hz / 10);
158 	}
159 	mtx_unlock(&sc->queue_mtx);
160 
161 	sc->dcp->free(sc->dcp);
162 	free(sc->toc, M_GEOM_UZIP);
163 	mtx_destroy(&sc->queue_mtx);
164 	mtx_destroy(&sc->last_mtx);
165 	free(sc->last_buf, M_GEOM_UZIP);
166 	free(sc, M_GEOM_UZIP);
167 	gp->softc = NULL;
168 }
169 
170 static int
171 g_uzip_cached(struct g_geom *gp, struct bio *bp)
172 {
173 	struct g_uzip_softc *sc;
174 	off_t ofs;
175 	size_t blk, blkofs, usz;
176 
177 	sc = gp->softc;
178 	ofs = bp->bio_offset + bp->bio_completed;
179 	blk = ofs / sc->blksz;
180 	mtx_lock(&sc->last_mtx);
181 	if (blk == sc->last_blk) {
182 		blkofs = ofs % sc->blksz;
183 		usz = sc->blksz - blkofs;
184 		if (bp->bio_resid < usz)
185 			usz = bp->bio_resid;
186 		memcpy(bp->bio_data + bp->bio_completed, sc->last_buf + blkofs,
187 		    usz);
188 		sc->req_cached++;
189 		mtx_unlock(&sc->last_mtx);
190 
191 		DPRINTF(GUZ_DBG_IO, ("%s/%s: %p: offset=%jd: got %jd bytes "
192 		    "from cache\n", __func__, gp->name, bp, (intmax_t)ofs,
193 		    (intmax_t)usz));
194 
195 		bp->bio_completed += usz;
196 		bp->bio_resid -= usz;
197 
198 		if (bp->bio_resid == 0) {
199 			g_io_deliver(bp, 0);
200 			return (1);
201 		}
202 	} else
203 		mtx_unlock(&sc->last_mtx);
204 
205 	return (0);
206 }
207 
208 #define BLK_ENDS(sc, bi)	((sc)->toc[(bi)].offset + \
209     (sc)->toc[(bi)].blen)
210 
211 #define BLK_IS_CONT(sc, bi)	(BLK_ENDS((sc), (bi) - 1) == \
212     (sc)->toc[(bi)].offset)
213 #define	BLK_IS_NIL(sc, bi)	((sc)->toc[(bi)].blen == 0)
214 
215 #define TOFF_2_BOFF(sc, pp, bi)	    ((sc)->toc[(bi)].offset - \
216     (sc)->toc[(bi)].offset % (pp)->sectorsize)
217 #define	TLEN_2_BLEN(sc, pp, bp, ei) roundup(BLK_ENDS((sc), (ei)) - \
218     (bp)->bio_offset, (pp)->sectorsize)
219 
220 static int
221 g_uzip_request(struct g_geom *gp, struct bio *bp)
222 {
223 	struct g_uzip_softc *sc;
224 	struct bio *bp2;
225 	struct g_consumer *cp;
226 	struct g_provider *pp;
227 	off_t ofs, start_blk_ofs;
228 	size_t i, start_blk, end_blk, zsize;
229 
230 	if (g_uzip_cached(gp, bp) != 0)
231 		return (1);
232 
233 	sc = gp->softc;
234 
235 	cp = LIST_FIRST(&gp->consumer);
236 	pp = cp->provider;
237 
238 	ofs = bp->bio_offset + bp->bio_completed;
239 	start_blk = ofs / sc->blksz;
240 	KASSERT(start_blk < sc->nblocks, ("start_blk out of range"));
241 	end_blk = howmany(ofs + bp->bio_resid, sc->blksz);
242 	KASSERT(end_blk <= sc->nblocks, ("end_blk out of range"));
243 
244 	for (; BLK_IS_NIL(sc, start_blk) && start_blk < end_blk; start_blk++) {
245 		/* Fill in any leading Nil blocks */
246 		start_blk_ofs = ofs % sc->blksz;
247 		zsize = MIN(sc->blksz - start_blk_ofs, bp->bio_resid);
248 		DPRINTF_BLK(GUZ_DBG_IO, start_blk, ("%s/%s: %p/%ju: "
249 		    "filling %ju zero bytes\n", __func__, gp->name, gp,
250 		    (uintmax_t)bp->bio_completed, (uintmax_t)zsize));
251 		bzero(bp->bio_data + bp->bio_completed, zsize);
252 		bp->bio_completed += zsize;
253 		bp->bio_resid -= zsize;
254 		ofs += zsize;
255 	}
256 
257 	if (start_blk == end_blk) {
258 		KASSERT(bp->bio_resid == 0, ("bp->bio_resid is invalid"));
259 		/*
260 		 * No non-Nil data is left, complete request immediately.
261 		 */
262 		DPRINTF(GUZ_DBG_IO, ("%s/%s: %p: all done returning %ju "
263 		    "bytes\n", __func__, gp->name, gp,
264 		    (uintmax_t)bp->bio_completed));
265 		g_io_deliver(bp, 0);
266 		return (1);
267 	}
268 
269 	for (i = start_blk + 1; i < end_blk; i++) {
270 		/* Trim discontinuous areas if any */
271 		if (!BLK_IS_CONT(sc, i)) {
272 			end_blk = i;
273 			break;
274 		}
275 	}
276 
277 	DPRINTF_BRNG(GUZ_DBG_IO, start_blk, end_blk, ("%s/%s: %p: "
278 	    "start=%u (%ju[%jd]), end=%u (%ju)\n", __func__, gp->name, bp,
279 	    (u_int)start_blk, (uintmax_t)sc->toc[start_blk].offset,
280 	    (intmax_t)sc->toc[start_blk].blen,
281 	    (u_int)end_blk, (uintmax_t)BLK_ENDS(sc, end_blk - 1)));
282 
283 	bp2 = g_clone_bio(bp);
284 	if (bp2 == NULL) {
285 		g_io_deliver(bp, ENOMEM);
286 		return (1);
287 	}
288 	bp2->bio_done = g_uzip_read_done;
289 
290 	bp2->bio_offset = TOFF_2_BOFF(sc, pp, start_blk);
291 	while (1) {
292 		bp2->bio_length = TLEN_2_BLEN(sc, pp, bp2, end_blk - 1);
293 		if (bp2->bio_length <= maxphys) {
294 			break;
295 		}
296 		if (end_blk == (start_blk + 1)) {
297 			break;
298 		}
299 		end_blk--;
300 	}
301 
302 	DPRINTF(GUZ_DBG_IO, ("%s/%s: bp2->bio_length = %jd, "
303 	    "bp2->bio_offset = %jd\n", __func__, gp->name,
304 	    (intmax_t)bp2->bio_length, (intmax_t)bp2->bio_offset));
305 
306 	bp2->bio_data = malloc(bp2->bio_length, M_GEOM_UZIP, M_NOWAIT);
307 	if (bp2->bio_data == NULL) {
308 		g_destroy_bio(bp2);
309 		g_io_deliver(bp, ENOMEM);
310 		return (1);
311 	}
312 
313 	DPRINTF_BRNG(GUZ_DBG_IO, start_blk, end_blk, ("%s/%s: %p: "
314 	    "reading %jd bytes from offset %jd\n", __func__, gp->name, bp,
315 	    (intmax_t)bp2->bio_length, (intmax_t)bp2->bio_offset));
316 
317 	g_io_request(bp2, cp);
318 	return (0);
319 }
320 
321 static void
322 g_uzip_read_done(struct bio *bp)
323 {
324 	struct bio *bp2;
325 	struct g_geom *gp;
326 	struct g_uzip_softc *sc;
327 
328 	bp2 = bp->bio_parent;
329 	gp = bp2->bio_to->geom;
330 	sc = gp->softc;
331 
332 	mtx_lock(&sc->queue_mtx);
333 	bioq_disksort(&sc->bio_queue, bp);
334 	mtx_unlock(&sc->queue_mtx);
335 	wakeup(sc);
336 }
337 
338 static int
339 g_uzip_memvcmp(const void *memory, unsigned char val, size_t size)
340 {
341 	const u_char *mm;
342 
343 	mm = (const u_char *)memory;
344 	return (*mm == val) && memcmp(mm, mm + 1, size - 1) == 0;
345 }
346 
347 static void
348 g_uzip_do(struct g_uzip_softc *sc, struct bio *bp)
349 {
350 	struct bio *bp2;
351 	struct g_provider *pp;
352 	struct g_consumer *cp;
353 	struct g_geom *gp;
354 	char *data, *data2;
355 	off_t ofs;
356 	size_t blk, blkofs, len, ulen, firstblk;
357 	int err;
358 
359 	bp2 = bp->bio_parent;
360 	gp = bp2->bio_to->geom;
361 
362 	cp = LIST_FIRST(&gp->consumer);
363 	pp = cp->provider;
364 
365 	bp2->bio_error = bp->bio_error;
366 	if (bp2->bio_error != 0)
367 		goto done;
368 
369 	/* Make sure there's forward progress. */
370 	if (bp->bio_completed == 0) {
371 		bp2->bio_error = ECANCELED;
372 		goto done;
373 	}
374 
375 	ofs = bp2->bio_offset + bp2->bio_completed;
376 	firstblk = blk = ofs / sc->blksz;
377 	blkofs = ofs % sc->blksz;
378 	data = bp->bio_data + sc->toc[blk].offset % pp->sectorsize;
379 	data2 = bp2->bio_data + bp2->bio_completed;
380 	while (bp->bio_completed && bp2->bio_resid) {
381 		if (blk > firstblk && !BLK_IS_CONT(sc, blk)) {
382 			DPRINTF_BLK(GUZ_DBG_IO, blk, ("%s/%s: %p: backref'ed "
383 			    "cluster #%u requested, looping around\n",
384 			    __func__, gp->name, bp2, (u_int)blk));
385 			goto done;
386 		}
387 		ulen = MIN(sc->blksz - blkofs, bp2->bio_resid);
388 		len = sc->toc[blk].blen;
389 		DPRINTF(GUZ_DBG_IO, ("%s/%s: %p/%ju: data2=%p, ulen=%u, "
390 		    "data=%p, len=%u\n", __func__, gp->name, gp,
391 		    bp->bio_completed, data2, (u_int)ulen, data, (u_int)len));
392 		if (len == 0) {
393 			/* All zero block: no cache update */
394 zero_block:
395 			bzero(data2, ulen);
396 		} else if (len <= bp->bio_completed) {
397 			mtx_lock(&sc->last_mtx);
398 			err = sc->dcp->decompress(sc->dcp, gp->name, data,
399 			    len, sc->last_buf);
400 			if (err != 0 && sc->toc[blk].last != 0) {
401 				/*
402 				 * Last block decompression has failed, check
403 				 * if it's just zero padding.
404 				 */
405 				if (g_uzip_memvcmp(data, '\0', len) == 0) {
406 					sc->toc[blk].blen = 0;
407 					sc->last_blk = -1;
408 					mtx_unlock(&sc->last_mtx);
409 					len = 0;
410 					goto zero_block;
411 				}
412 			}
413 			if (err != 0) {
414 				sc->last_blk = -1;
415 				mtx_unlock(&sc->last_mtx);
416 				bp2->bio_error = EILSEQ;
417 				DPRINTF(GUZ_DBG_ERR, ("%s/%s: decompress"
418 				    "(%p, %ju, %ju) failed\n", __func__,
419 				    gp->name, sc->dcp, (uintmax_t)blk,
420 				    (uintmax_t)len));
421 				goto done;
422 			}
423 			sc->last_blk = blk;
424 			memcpy(data2, sc->last_buf + blkofs, ulen);
425 			mtx_unlock(&sc->last_mtx);
426 			err = sc->dcp->rewind(sc->dcp, gp->name);
427 			if (err != 0) {
428 				bp2->bio_error = EILSEQ;
429 				DPRINTF(GUZ_DBG_ERR, ("%s/%s: rewind(%p) "
430 				    "failed\n", __func__, gp->name, sc->dcp));
431 				goto done;
432 			}
433 			data += len;
434 		} else
435 			break;
436 
437 		data2 += ulen;
438 		bp2->bio_completed += ulen;
439 		bp2->bio_resid -= ulen;
440 		bp->bio_completed -= len;
441 		blkofs = 0;
442 		blk++;
443 	}
444 
445 done:
446 	/* Finish processing the request. */
447 	free(bp->bio_data, M_GEOM_UZIP);
448 	g_destroy_bio(bp);
449 	if (bp2->bio_error != 0 || bp2->bio_resid == 0)
450 		g_io_deliver(bp2, bp2->bio_error);
451 	else
452 		g_uzip_request(gp, bp2);
453 }
454 
455 static void
456 g_uzip_start(struct bio *bp)
457 {
458 	struct g_provider *pp;
459 	struct g_geom *gp;
460 	struct g_uzip_softc *sc;
461 
462 	pp = bp->bio_to;
463 	gp = pp->geom;
464 
465 	DPRINTF(GUZ_DBG_IO, ("%s/%s: %p: cmd=%d, offset=%jd, length=%jd, "
466 	    "buffer=%p\n", __func__, gp->name, bp, bp->bio_cmd,
467 	    (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length, bp->bio_data));
468 
469 	sc = gp->softc;
470 	sc->req_total++;
471 
472 	if (bp->bio_cmd == BIO_GETATTR) {
473 		struct bio *bp2;
474 		struct g_consumer *cp;
475 		struct g_geom *gp;
476 		struct g_provider *pp;
477 
478 		/* pass on MNT:* requests and ignore others */
479 		if (strncmp(bp->bio_attribute, "MNT:", 4) == 0) {
480 			bp2 = g_clone_bio(bp);
481 			if (bp2 == NULL) {
482 				g_io_deliver(bp, ENOMEM);
483 				return;
484 			}
485 			bp2->bio_done = g_std_done;
486 			pp = bp->bio_to;
487 			gp = pp->geom;
488 			cp = LIST_FIRST(&gp->consumer);
489 			g_io_request(bp2, cp);
490 			return;
491 		}
492 	}
493 	if (bp->bio_cmd != BIO_READ) {
494 		g_io_deliver(bp, EOPNOTSUPP);
495 		return;
496 	}
497 
498 	bp->bio_resid = bp->bio_length;
499 	bp->bio_completed = 0;
500 
501 	g_uzip_request(gp, bp);
502 }
503 
504 static void
505 g_uzip_orphan(struct g_consumer *cp)
506 {
507 	struct g_geom *gp;
508 
509 	g_topology_assert();
510 	G_VALID_CONSUMER(cp);
511 	gp = cp->geom;
512 	g_trace(G_T_TOPOLOGY, "%s(%p/%s)", __func__, cp, gp->name);
513 	g_wither_geom(gp, ENXIO);
514 
515 	/*
516 	 * We can safely free the softc now if there are no accesses,
517 	 * otherwise g_uzip_access() will do that after the last close.
518 	 */
519 	if ((cp->acr + cp->acw + cp->ace) == 0)
520 		g_uzip_softc_free(gp);
521 }
522 
523 static void
524 g_uzip_spoiled(struct g_consumer *cp)
525 {
526 
527 	g_trace(G_T_TOPOLOGY, "%s(%p/%s)", __func__, cp, cp->geom->name);
528 	cp->flags |= G_CF_ORPHAN;
529 	g_uzip_orphan(cp);
530 }
531 
532 static int
533 g_uzip_access(struct g_provider *pp, int dr, int dw, int de)
534 {
535 	struct g_geom *gp;
536 	struct g_consumer *cp;
537 	int error;
538 
539 	gp = pp->geom;
540 	cp = LIST_FIRST(&gp->consumer);
541 	KASSERT (cp != NULL, ("g_uzip_access but no consumer"));
542 
543 	if (cp->acw + dw > 0)
544 		return (EROFS);
545 
546 	error = g_access(cp, dr, dw, de);
547 
548 	/*
549 	 * Free the softc if all providers have been closed and this geom
550 	 * is being removed.
551 	 */
552 	if (error == 0 && (gp->flags & G_GEOM_WITHER) != 0 &&
553 	    (cp->acr + cp->acw + cp->ace) == 0)
554 		g_uzip_softc_free(gp);
555 
556 	return (error);
557 }
558 
559 static int
560 g_uzip_parse_toc(struct g_uzip_softc *sc, struct g_provider *pp,
561     struct g_geom *gp)
562 {
563 	uint32_t i, j, backref_to;
564 	uint64_t max_offset, min_offset;
565 	struct g_uzip_blk *last_blk;
566 
567 	min_offset = sizeof(struct cloop_header) +
568 	    (sc->nblocks + 1) * sizeof(uint64_t);
569 	max_offset = sc->toc[0].offset - 1;
570 	last_blk = &sc->toc[0];
571 	for (i = 0; i < sc->nblocks; i++) {
572 		/* First do some bounds checking */
573 		if ((sc->toc[i].offset < min_offset) ||
574 		    (sc->toc[i].offset > pp->mediasize)) {
575 			goto error_offset;
576 		}
577 		DPRINTF_BLK(GUZ_DBG_IO, i, ("%s: cluster #%u "
578 		    "offset=%ju max_offset=%ju\n", gp->name,
579 		    (u_int)i, (uintmax_t)sc->toc[i].offset,
580 		    (uintmax_t)max_offset));
581 		backref_to = BLEN_UNDEF;
582 		if (sc->toc[i].offset < max_offset) {
583 			/*
584 			 * For the backref'ed blocks search already parsed
585 			 * TOC entries for the matching offset and copy the
586 			 * size from matched entry.
587 			 */
588 			for (j = 0; j <= i; j++) {
589                                 if (sc->toc[j].offset == sc->toc[i].offset &&
590 				    !BLK_IS_NIL(sc, j)) {
591                                         break;
592                                 }
593                                 if (j != i) {
594 					continue;
595 				}
596 				DPRINTF(GUZ_DBG_ERR, ("%s: cannot match "
597 				    "backref'ed offset at cluster #%u\n",
598 				    gp->name, i));
599 				return (-1);
600 			}
601 			sc->toc[i].blen = sc->toc[j].blen;
602 			backref_to = j;
603 		} else {
604 			last_blk = &sc->toc[i];
605 			/*
606 			 * For the "normal blocks" seek forward until we hit
607 			 * block whose offset is larger than ours and assume
608 			 * it's going to be the next one.
609 			 */
610 			for (j = i + 1; j < sc->nblocks + 1; j++) {
611 				if (sc->toc[j].offset > max_offset) {
612 					break;
613 				}
614 			}
615 			sc->toc[i].blen = sc->toc[j].offset -
616 			    sc->toc[i].offset;
617 			if (BLK_ENDS(sc, i) > pp->mediasize) {
618 				DPRINTF(GUZ_DBG_ERR, ("%s: cluster #%u "
619 				    "extends past media boundary (%ju > %ju)\n",
620 				    gp->name, (u_int)i,
621 				    (uintmax_t)BLK_ENDS(sc, i),
622 				    (intmax_t)pp->mediasize));
623 				return (-1);
624 			}
625 			KASSERT(max_offset <= sc->toc[i].offset, (
626 			    "%s: max_offset is incorrect: %ju",
627 			    gp->name, (uintmax_t)max_offset));
628 			max_offset = BLK_ENDS(sc, i) - 1;
629 		}
630 		DPRINTF_BLK(GUZ_DBG_TOC, i, ("%s: cluster #%u, original %u "
631 		    "bytes, in %u bytes", gp->name, i, sc->blksz,
632 		    sc->toc[i].blen));
633 		if (backref_to != BLEN_UNDEF) {
634 			DPRINTF_BLK(GUZ_DBG_TOC, i, (" (->#%u)",
635 			    (u_int)backref_to));
636 		}
637 		DPRINTF_BLK(GUZ_DBG_TOC, i, ("\n"));
638 	}
639 	last_blk->last = 1;
640 	/* Do a second pass to validate block lengths */
641 	for (i = 0; i < sc->nblocks; i++) {
642 		if (sc->toc[i].blen > sc->dcp->max_blen) {
643 			if (sc->toc[i].last == 0) {
644 				DPRINTF(GUZ_DBG_ERR, ("%s: cluster #%u "
645 				    "length (%ju) exceeds "
646 				    "max_blen (%ju)\n", gp->name, i,
647 				    (uintmax_t)sc->toc[i].blen,
648 				    (uintmax_t)sc->dcp->max_blen));
649 				return (-1);
650 			}
651 			DPRINTF(GUZ_DBG_INFO, ("%s: cluster #%u extra "
652 			    "padding is detected, trimmed to %ju\n",
653 			    gp->name, i, (uintmax_t)sc->dcp->max_blen));
654 			    sc->toc[i].blen = sc->dcp->max_blen;
655 			sc->toc[i].padded = 1;
656 		}
657 	}
658 	return (0);
659 
660 error_offset:
661 	DPRINTF(GUZ_DBG_ERR, ("%s: cluster #%u: invalid offset %ju, "
662 	    "min_offset=%ju mediasize=%jd\n", gp->name, (u_int)i,
663 	    sc->toc[i].offset, min_offset, pp->mediasize));
664 	return (-1);
665 }
666 
667 static struct g_geom *
668 g_uzip_taste(struct g_class *mp, struct g_provider *pp, int flags)
669 {
670 	int error;
671 	uint32_t i, total_offsets, offsets_read, blk;
672 	void *buf;
673 	struct cloop_header *header;
674 	struct g_consumer *cp;
675 	struct g_geom *gp;
676 	struct g_provider *pp2;
677 	struct g_uzip_softc *sc;
678 	struct g_geom_alias *gap;
679 	enum {
680 		G_UZIP = 1,
681 		G_ULZMA,
682 		G_ZSTD,
683 	} type;
684 	char cloop_version;
685 
686 	g_trace(G_T_TOPOLOGY, "%s(%s,%s)", __func__, mp->name, pp->name);
687 	g_topology_assert();
688 
689 	/* Skip providers that are already open for writing. */
690 	if (pp->acw > 0)
691 		return (NULL);
692 
693 	if ((fnmatch(g_uzip_attach_to, pp->name, 0) != 0) ||
694 	    (fnmatch(g_uzip_noattach_to, pp->name, 0) == 0)) {
695 		DPRINTF(GUZ_DBG_INFO, ("%s(%s,%s), ignoring\n", __func__,
696 		    mp->name, pp->name));
697 		return (NULL);
698 	}
699 
700 	buf = NULL;
701 
702 	/*
703 	 * Create geom instance.
704 	 */
705 	gp = g_new_geomf(mp, GUZ_DEV_NAME("%s"), pp->name);
706 	cp = g_new_consumer(gp);
707 	error = g_attach(cp, pp);
708 	if (error != 0)
709 		goto e0;
710 	error = g_access(cp, 1, 0, 0);
711 	if (error)
712 		goto e1;
713 	g_topology_unlock();
714 
715 	/*
716 	 * Read cloop header, look for CLOOP magic, perform
717 	 * other validity checks.
718 	 */
719 	DPRINTF(GUZ_DBG_INFO, ("%s: media sectorsize %u, mediasize %jd\n",
720 	    gp->name, pp->sectorsize, (intmax_t)pp->mediasize));
721 	buf = g_read_data(cp, 0, pp->sectorsize, NULL);
722 	if (buf == NULL)
723 		goto e2;
724 	header = (struct cloop_header *) buf;
725 	if (strncmp(header->magic, CLOOP_MAGIC_START,
726 	    sizeof(CLOOP_MAGIC_START) - 1) != 0) {
727 		DPRINTF(GUZ_DBG_ERR, ("%s: no CLOOP magic\n", gp->name));
728 		goto e3;
729 	}
730 
731 	cloop_version = header->magic[CLOOP_OFS_VERSN];
732 	switch (header->magic[CLOOP_OFS_COMPR]) {
733 	case CLOOP_COMP_LZMA:
734 	case CLOOP_COMP_LZMA_DDP:
735 		type = G_ULZMA;
736 		if (cloop_version < CLOOP_MINVER_LZMA) {
737 			DPRINTF(GUZ_DBG_ERR, ("%s: image version too old\n",
738 			    gp->name));
739 			goto e3;
740 		}
741 		DPRINTF(GUZ_DBG_INFO, ("%s: GEOM_UZIP_LZMA image found\n",
742 		    gp->name));
743 		break;
744 	case CLOOP_COMP_LIBZ:
745 	case CLOOP_COMP_LIBZ_DDP:
746 		type = G_UZIP;
747 		if (cloop_version < CLOOP_MINVER_ZLIB) {
748 			DPRINTF(GUZ_DBG_ERR, ("%s: image version too old\n",
749 			    gp->name));
750 			goto e3;
751 		}
752 		DPRINTF(GUZ_DBG_INFO, ("%s: GEOM_UZIP_ZLIB image found\n",
753 		    gp->name));
754 		break;
755 	case CLOOP_COMP_ZSTD:
756 	case CLOOP_COMP_ZSTD_DDP:
757 		if (cloop_version < CLOOP_MINVER_ZSTD) {
758 			DPRINTF(GUZ_DBG_ERR, ("%s: image version too old\n",
759 			    gp->name));
760 			goto e3;
761 		}
762 #ifdef ZSTDIO
763 		DPRINTF(GUZ_DBG_INFO, ("%s: GEOM_UZIP_ZSTD image found.\n",
764 		    gp->name));
765 		type = G_ZSTD;
766 #else
767 		DPRINTF(GUZ_DBG_ERR, ("%s: GEOM_UZIP_ZSTD image found, but "
768 		    "this kernel was configured with Zstd disabled.\n",
769 		    gp->name));
770 		goto e3;
771 #endif
772 		break;
773 	default:
774 		DPRINTF(GUZ_DBG_ERR, ("%s: unsupported image type\n",
775 		    gp->name));
776                 goto e3;
777         }
778 
779 	/*
780 	 * Initialize softc and read offsets.
781 	 */
782 	sc = malloc(sizeof(*sc), M_GEOM_UZIP, M_WAITOK | M_ZERO);
783 	gp->softc = sc;
784 	sc->blksz = ntohl(header->blksz);
785 	sc->nblocks = ntohl(header->nblocks);
786 	if (sc->blksz % 512 != 0) {
787 		printf("%s: block size (%u) should be multiple of 512.\n",
788 		    gp->name, sc->blksz);
789 		goto e4;
790 	}
791 	if (sc->blksz > MAX_BLKSZ) {
792 		printf("%s: block size (%u) should not be larger than %lu.\n",
793 		    gp->name, sc->blksz, MAX_BLKSZ);
794 	}
795 	total_offsets = sc->nblocks + 1;
796 	if (sizeof(struct cloop_header) +
797 	    total_offsets * sizeof(uint64_t) > pp->mediasize) {
798 		printf("%s: media too small for %u blocks\n",
799 		    gp->name, sc->nblocks);
800 		goto e4;
801 	}
802 	sc->toc = malloc(total_offsets * sizeof(struct g_uzip_blk),
803 	    M_GEOM_UZIP, M_WAITOK | M_ZERO);
804 	offsets_read = MIN(total_offsets,
805 	    (pp->sectorsize - sizeof(*header)) / sizeof(uint64_t));
806 	for (i = 0; i < offsets_read; i++) {
807 		sc->toc[i].offset = be64toh(((uint64_t *) (header + 1))[i]);
808 		sc->toc[i].blen = BLEN_UNDEF;
809 	}
810 	DPRINTF(GUZ_DBG_INFO, ("%s: %u offsets in the first sector\n",
811 	       gp->name, offsets_read));
812 
813 	/*
814 	 * The following invalidates the "header" pointer into the first
815 	 * block's "buf."
816 	 */
817 	header = NULL;
818 
819 	for (blk = 1; offsets_read < total_offsets; blk++) {
820 		uint32_t nread;
821 
822 		free(buf, M_GEOM);
823 		buf = g_read_data(
824 		    cp, blk * pp->sectorsize, pp->sectorsize, NULL);
825 		if (buf == NULL)
826 			goto e5;
827 		nread = MIN(total_offsets - offsets_read,
828 		     pp->sectorsize / sizeof(uint64_t));
829 		DPRINTF(GUZ_DBG_TOC, ("%s: %u offsets read from sector %d\n",
830 		    gp->name, nread, blk));
831 		for (i = 0; i < nread; i++) {
832 			sc->toc[offsets_read + i].offset =
833 			    be64toh(((uint64_t *) buf)[i]);
834 			sc->toc[offsets_read + i].blen = BLEN_UNDEF;
835 		}
836 		offsets_read += nread;
837 	}
838 	free(buf, M_GEOM);
839 	buf = NULL;
840 	offsets_read -= 1;
841 	DPRINTF(GUZ_DBG_INFO, ("%s: done reading %u block offsets from %u "
842 	    "sectors\n", gp->name, offsets_read, blk));
843 	if (sc->nblocks != offsets_read) {
844 		DPRINTF(GUZ_DBG_ERR, ("%s: read %s offsets than expected "
845 		    "blocks\n", gp->name,
846 		    sc->nblocks < offsets_read ? "more" : "less"));
847 		goto e5;
848 	}
849 
850 	switch (type) {
851 	case G_UZIP:
852 		sc->dcp = g_uzip_zlib_ctor(sc->blksz);
853 		break;
854 	case G_ULZMA:
855 		sc->dcp = g_uzip_lzma_ctor(sc->blksz);
856 		break;
857 #ifdef ZSTDIO
858 	case G_ZSTD:
859 		sc->dcp = g_uzip_zstd_ctor(sc->blksz);
860 		break;
861 #endif
862 	default:
863 		goto e5;
864 	}
865 
866 	/*
867 	 * The last+1 block was not always initialized by earlier versions of
868 	 * mkuzip(8).  However, *if* it is initialized, the difference between
869 	 * its offset and the prior block's offset represents the length of the
870 	 * final real compressed block, and this is significant to the
871 	 * decompressor.
872 	 */
873 	if (cloop_version >= CLOOP_MINVER_RELIABLE_LASTBLKSZ &&
874 	    sc->toc[sc->nblocks].offset != 0) {
875 		if (sc->toc[sc->nblocks].offset > pp->mediasize) {
876 			DPRINTF(GUZ_DBG_ERR,
877 			    ("%s: bogus n+1 offset %ju > mediasize %ju\n",
878 			     gp->name, (uintmax_t)sc->toc[sc->nblocks].offset,
879 			     (uintmax_t)pp->mediasize));
880 			goto e6;
881 		}
882 	} else {
883 		sc->toc[sc->nblocks].offset = pp->mediasize;
884 	}
885 	/* Massage TOC (table of contents), make sure it is sound */
886 	if (g_uzip_parse_toc(sc, pp, gp) != 0) {
887 		DPRINTF(GUZ_DBG_ERR, ("%s: TOC error\n", gp->name));
888 		goto e6;
889 	}
890 	mtx_init(&sc->last_mtx, "geom_uzip cache", NULL, MTX_DEF);
891 	mtx_init(&sc->queue_mtx, "geom_uzip wrkthread", NULL, MTX_DEF);
892 	bioq_init(&sc->bio_queue);
893 	sc->last_blk = -1;
894 	sc->last_buf = malloc(sc->blksz, M_GEOM_UZIP, M_WAITOK);
895 	sc->req_total = 0;
896 	sc->req_cached = 0;
897 
898 	sc->uzip_do = &g_uzip_do;
899 
900 	error = kproc_create(g_uzip_wrkthr, sc, &sc->procp, 0, 0, "%s",
901 	    gp->name);
902 	if (error != 0) {
903 		goto e7;
904 	}
905 
906 	g_topology_lock();
907 	pp2 = g_new_providerf(gp, "%s", gp->name);
908 	pp2->sectorsize = 512;
909 	pp2->mediasize = (off_t)sc->nblocks * sc->blksz;
910 	pp2->stripesize = pp->stripesize;
911 	pp2->stripeoffset = pp->stripeoffset;
912 	LIST_FOREACH(gap, &pp->aliases, ga_next)
913 		g_provider_add_alias(pp2, GUZ_DEV_NAME("%s"), gap->ga_alias);
914 	g_error_provider(pp2, 0);
915 	g_access(cp, -1, 0, 0);
916 
917 	DPRINTF(GUZ_DBG_INFO, ("%s: taste ok (%d, %ju), (%ju, %ju), %x\n",
918 	    gp->name, pp2->sectorsize, (uintmax_t)pp2->mediasize,
919 	    (uintmax_t)pp2->stripeoffset, (uintmax_t)pp2->stripesize, pp2->flags));
920 	DPRINTF(GUZ_DBG_INFO, ("%s: %u x %u blocks\n", gp->name, sc->nblocks,
921 	    sc->blksz));
922 	return (gp);
923 
924 e7:
925 	free(sc->last_buf, M_GEOM);
926 	mtx_destroy(&sc->queue_mtx);
927 	mtx_destroy(&sc->last_mtx);
928 e6:
929 	sc->dcp->free(sc->dcp);
930 e5:
931 	free(sc->toc, M_GEOM);
932 e4:
933 	free(gp->softc, M_GEOM_UZIP);
934 e3:
935 	if (buf != NULL) {
936 		free(buf, M_GEOM);
937 	}
938 e2:
939 	g_topology_lock();
940 	g_access(cp, -1, 0, 0);
941 e1:
942 	g_detach(cp);
943 e0:
944 	g_destroy_consumer(cp);
945 	g_destroy_geom(gp);
946 
947 	return (NULL);
948 }
949 
950 static int
951 g_uzip_destroy_geom(struct gctl_req *req, struct g_class *mp, struct g_geom *gp)
952 {
953 	struct g_provider *pp;
954 
955 	KASSERT(gp != NULL, ("NULL geom"));
956 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, gp->name);
957 	g_topology_assert();
958 
959 	if (gp->softc == NULL) {
960 		DPRINTF(GUZ_DBG_ERR, ("%s(%s): gp->softc == NULL\n", __func__,
961 		    gp->name));
962 		return (ENXIO);
963 	}
964 
965 	pp = LIST_FIRST(&gp->provider);
966 	KASSERT(pp != NULL, ("NULL provider"));
967 	if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0)
968 		return (EBUSY);
969 
970 	g_wither_geom(gp, ENXIO);
971 	g_uzip_softc_free(gp);
972 	return (0);
973 }
974 
975 static struct g_class g_uzip_class = {
976 	.name = UZIP_CLASS_NAME,
977 	.version = G_VERSION,
978 	.taste = g_uzip_taste,
979 	.destroy_geom = g_uzip_destroy_geom,
980 
981 	.start = g_uzip_start,
982 	.orphan = g_uzip_orphan,
983 	.access = g_uzip_access,
984 	.spoiled = g_uzip_spoiled,
985 };
986 
987 DECLARE_GEOM_CLASS(g_uzip_class, g_uzip);
988 MODULE_DEPEND(g_uzip, xz, 1, 1, 1);
989 MODULE_DEPEND(g_uzip, zlib, 1, 1, 1);
990 MODULE_VERSION(geom_uzip, 0);
991