xref: /freebsd/sys/kern/subr_compressor.c (revision 0957b409) 
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2014, 2017 Mark Johnston <markj@FreeBSD.org>
5  * Copyright (c) 2017 Conrad Meyer <cem@FreeBSD.org>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions are
9  * met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in
14  *    the documentation and/or other materials provided with the
15  *    distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 /*
31  * Subroutines used for writing compressed user process and kernel core dumps.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include "opt_gzio.h"
38 #include "opt_zstdio.h"
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 
43 #include <sys/compressor.h>
44 #include <sys/kernel.h>
45 #include <sys/linker_set.h>
46 #include <sys/malloc.h>
47 
48 MALLOC_DEFINE(M_COMPRESS, "compressor", "kernel compression subroutines");
49 
50 struct compressor_methods {
51 	int format;
52 	void *(* const init)(size_t, int);
53 	void (* const reset)(void *);
54 	int (* const write)(void *, void *, size_t, compressor_cb_t, void *);
55 	void (* const fini)(void *);
56 };
57 
58 struct compressor {
59 	const struct compressor_methods *methods;
60 	compressor_cb_t cb;
61 	void *priv;
62 	void *arg;
63 };
64 
65 SET_DECLARE(compressors, struct compressor_methods);
66 
67 #ifdef GZIO
68 
69 #include <sys/zutil.h>
70 
71 struct gz_stream {
72 	uint8_t		*gz_buffer;	/* output buffer */
73 	size_t		gz_bufsz;	/* output buffer size */
74 	off_t		gz_off;		/* offset into the output stream */
75 	uint32_t	gz_crc;		/* stream CRC32 */
76 	z_stream	gz_stream;	/* zlib state */
77 };
78 
79 static void 	*gz_init(size_t maxiosize, int level);
80 static void	gz_reset(void *stream);
81 static int	gz_write(void *stream, void *data, size_t len, compressor_cb_t,
82 		    void *);
83 static void	gz_fini(void *stream);
84 
85 static void *
86 gz_alloc(void *arg __unused, u_int n, u_int sz)
87 {
88 
89 	/*
90 	 * Memory for zlib state is allocated using M_NODUMP since it may be
91 	 * used to compress a kernel dump, and we don't want zlib to attempt to
92 	 * compress its own state.
93 	 */
94 	return (malloc(n * sz, M_COMPRESS, M_WAITOK | M_ZERO | M_NODUMP));
95 }
96 
97 static void
98 gz_free(void *arg __unused, void *ptr)
99 {
100 
101 	free(ptr, M_COMPRESS);
102 }
103 
104 static void *
105 gz_init(size_t maxiosize, int level)
106 {
107 	struct gz_stream *s;
108 	int error;
109 
110 	s = gz_alloc(NULL, 1, roundup2(sizeof(*s), PAGE_SIZE));
111 	s->gz_buffer = gz_alloc(NULL, 1, maxiosize);
112 	s->gz_bufsz = maxiosize;
113 
114 	s->gz_stream.zalloc = gz_alloc;
115 	s->gz_stream.zfree = gz_free;
116 	s->gz_stream.opaque = NULL;
117 	s->gz_stream.next_in = Z_NULL;
118 	s->gz_stream.avail_in = 0;
119 
120 	error = deflateInit2(&s->gz_stream, level, Z_DEFLATED, -MAX_WBITS,
121 	    DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
122 	if (error != 0)
123 		goto fail;
124 
125 	gz_reset(s);
126 
127 	return (s);
128 
129 fail:
130 	gz_free(NULL, s);
131 	return (NULL);
132 }
133 
134 static void
135 gz_reset(void *stream)
136 {
137 	struct gz_stream *s;
138 	uint8_t *hdr;
139 	const size_t hdrlen = 10;
140 
141 	s = stream;
142 	s->gz_off = 0;
143 	s->gz_crc = ~0U;
144 
145 	(void)deflateReset(&s->gz_stream);
146 	s->gz_stream.avail_out = s->gz_bufsz;
147 	s->gz_stream.next_out = s->gz_buffer;
148 
149 	/* Write the gzip header to the output buffer. */
150 	hdr = s->gz_buffer;
151 	memset(hdr, 0, hdrlen);
152 	hdr[0] = 0x1f;
153 	hdr[1] = 0x8b;
154 	hdr[2] = Z_DEFLATED;
155 	hdr[9] = OS_CODE;
156 	s->gz_stream.next_out += hdrlen;
157 	s->gz_stream.avail_out -= hdrlen;
158 }
159 
160 static int
161 gz_write(void *stream, void *data, size_t len, compressor_cb_t cb,
162     void *arg)
163 {
164 	struct gz_stream *s;
165 	uint8_t trailer[8];
166 	size_t room;
167 	int error, zerror, zflag;
168 
169 	s = stream;
170 	zflag = data == NULL ? Z_FINISH : Z_NO_FLUSH;
171 
172 	if (len > 0) {
173 		s->gz_stream.avail_in = len;
174 		s->gz_stream.next_in = data;
175 		s->gz_crc = crc32_raw(data, len, s->gz_crc);
176 	} else
177 		s->gz_crc ^= ~0U;
178 
179 	error = 0;
180 	do {
181 		zerror = deflate(&s->gz_stream, zflag);
182 		if (zerror != Z_OK && zerror != Z_STREAM_END) {
183 			error = EIO;
184 			break;
185 		}
186 
187 		if (s->gz_stream.avail_out == 0 || zerror == Z_STREAM_END) {
188 			/*
189 			 * Our output buffer is full or there's nothing left
190 			 * to produce, so we're flushing the buffer.
191 			 */
192 			len = s->gz_bufsz - s->gz_stream.avail_out;
193 			if (zerror == Z_STREAM_END) {
194 				/*
195 				 * Try to pack as much of the trailer into the
196 				 * output buffer as we can.
197 				 */
198 				((uint32_t *)trailer)[0] = s->gz_crc;
199 				((uint32_t *)trailer)[1] =
200 				    s->gz_stream.total_in;
201 				room = MIN(sizeof(trailer),
202 				    s->gz_bufsz - len);
203 				memcpy(s->gz_buffer + len, trailer, room);
204 				len += room;
205 			}
206 
207 			error = cb(s->gz_buffer, len, s->gz_off, arg);
208 			if (error != 0)
209 				break;
210 
211 			s->gz_off += len;
212 			s->gz_stream.next_out = s->gz_buffer;
213 			s->gz_stream.avail_out = s->gz_bufsz;
214 
215 			/*
216 			 * If we couldn't pack the trailer into the output
217 			 * buffer, write it out now.
218 			 */
219 			if (zerror == Z_STREAM_END && room < sizeof(trailer))
220 				error = cb(trailer + room,
221 				    sizeof(trailer) - room, s->gz_off, arg);
222 		}
223 	} while (zerror != Z_STREAM_END &&
224 	    (zflag == Z_FINISH || s->gz_stream.avail_in > 0));
225 
226 	return (error);
227 }
228 
229 static void
230 gz_fini(void *stream)
231 {
232 	struct gz_stream *s;
233 
234 	s = stream;
235 	(void)deflateEnd(&s->gz_stream);
236 	gz_free(NULL, s->gz_buffer);
237 	gz_free(NULL, s);
238 }
239 
240 struct compressor_methods gzip_methods = {
241 	.format = COMPRESS_GZIP,
242 	.init = gz_init,
243 	.reset = gz_reset,
244 	.write = gz_write,
245 	.fini = gz_fini,
246 };
247 DATA_SET(compressors, gzip_methods);
248 
249 #endif /* GZIO */
250 
251 #ifdef ZSTDIO
252 
253 #define	ZSTD_STATIC_LINKING_ONLY
254 #include <contrib/zstd/lib/zstd.h>
255 
256 struct zstdio_stream {
257 	ZSTD_CCtx	*zst_stream;
258 	ZSTD_inBuffer	zst_inbuffer;
259 	ZSTD_outBuffer	zst_outbuffer;
260 	uint8_t *	zst_buffer;	/* output buffer */
261 	size_t		zst_maxiosz;	/* Max output IO size */
262 	off_t		zst_off;	/* offset into the output stream */
263 	void *		zst_static_wkspc;
264 };
265 
266 static void 	*zstdio_init(size_t maxiosize, int level);
267 static void	zstdio_reset(void *stream);
268 static int	zstdio_write(void *stream, void *data, size_t len,
269 		    compressor_cb_t, void *);
270 static void	zstdio_fini(void *stream);
271 
272 static void *
273 zstdio_init(size_t maxiosize, int level)
274 {
275 	ZSTD_CCtx *dump_compressor;
276 	struct zstdio_stream *s;
277 	void *wkspc, *owkspc, *buffer;
278 	size_t wkspc_size, buf_size, rc;
279 
280 	s = NULL;
281 	wkspc_size = ZSTD_estimateCStreamSize(level);
282 	owkspc = wkspc = malloc(wkspc_size + 8, M_COMPRESS,
283 	    M_WAITOK | M_NODUMP);
284 	/* Zstd API requires 8-byte alignment. */
285 	if ((uintptr_t)wkspc % 8 != 0)
286 		wkspc = (void *)roundup2((uintptr_t)wkspc, 8);
287 
288 	dump_compressor = ZSTD_initStaticCCtx(wkspc, wkspc_size);
289 	if (dump_compressor == NULL) {
290 		printf("%s: workspace too small.\n", __func__);
291 		goto out;
292 	}
293 
294 	rc = ZSTD_CCtx_setParameter(dump_compressor, ZSTD_c_checksumFlag, 1);
295 	if (ZSTD_isError(rc)) {
296 		printf("%s: error setting checksumFlag: %s\n", __func__,
297 		    ZSTD_getErrorName(rc));
298 		goto out;
299 	}
300 	rc = ZSTD_CCtx_setParameter(dump_compressor, ZSTD_c_compressionLevel,
301 	    level);
302 	if (ZSTD_isError(rc)) {
303 		printf("%s: error setting compressLevel: %s\n", __func__,
304 		    ZSTD_getErrorName(rc));
305 		goto out;
306 	}
307 
308 	buf_size = ZSTD_CStreamOutSize() * 2;
309 	buffer = malloc(buf_size, M_COMPRESS, M_WAITOK | M_NODUMP);
310 
311 	s = malloc(sizeof(*s), M_COMPRESS, M_NODUMP | M_WAITOK);
312 	s->zst_buffer = buffer;
313 	s->zst_outbuffer.dst = buffer;
314 	s->zst_outbuffer.size = buf_size;
315 	s->zst_maxiosz = maxiosize;
316 	s->zst_stream = dump_compressor;
317 	s->zst_static_wkspc = owkspc;
318 
319 	zstdio_reset(s);
320 
321 out:
322 	if (s == NULL)
323 		free(owkspc, M_COMPRESS);
324 	return (s);
325 }
326 
327 static void
328 zstdio_reset(void *stream)
329 {
330 	struct zstdio_stream *s;
331 	size_t res;
332 
333 	s = stream;
334 	res = ZSTD_resetCStream(s->zst_stream, 0);
335 	if (ZSTD_isError(res))
336 		panic("%s: could not reset stream %p: %s\n", __func__, s,
337 		    ZSTD_getErrorName(res));
338 
339 	s->zst_off = 0;
340 	s->zst_inbuffer.src = NULL;
341 	s->zst_inbuffer.size = 0;
342 	s->zst_inbuffer.pos = 0;
343 	s->zst_outbuffer.pos = 0;
344 }
345 
346 static int
347 zst_flush_intermediate(struct zstdio_stream *s, compressor_cb_t cb, void *arg)
348 {
349 	size_t bytes_to_dump;
350 	int error;
351 
352 	/* Flush as many full output blocks as possible. */
353 	/* XXX: 4096 is arbitrary safe HDD block size for kernel dumps */
354 	while (s->zst_outbuffer.pos >= 4096) {
355 		bytes_to_dump = rounddown(s->zst_outbuffer.pos, 4096);
356 
357 		if (bytes_to_dump > s->zst_maxiosz)
358 			bytes_to_dump = s->zst_maxiosz;
359 
360 		error = cb(s->zst_buffer, bytes_to_dump, s->zst_off, arg);
361 		if (error != 0)
362 			return (error);
363 
364 		/*
365 		 * Shift any non-full blocks up to the front of the output
366 		 * buffer.
367 		 */
368 		s->zst_outbuffer.pos -= bytes_to_dump;
369 		memmove(s->zst_outbuffer.dst,
370 		    (char *)s->zst_outbuffer.dst + bytes_to_dump,
371 		    s->zst_outbuffer.pos);
372 		s->zst_off += bytes_to_dump;
373 	}
374 	return (0);
375 }
376 
377 static int
378 zstdio_flush(struct zstdio_stream *s, compressor_cb_t cb, void *arg)
379 {
380 	size_t rc, lastpos;
381 	int error;
382 
383 	/*
384 	 * Positive return indicates unflushed data remaining; need to call
385 	 * endStream again after clearing out room in output buffer.
386 	 */
387 	rc = 1;
388 	lastpos = s->zst_outbuffer.pos;
389 	while (rc > 0) {
390 		rc = ZSTD_endStream(s->zst_stream, &s->zst_outbuffer);
391 		if (ZSTD_isError(rc)) {
392 			printf("%s: ZSTD_endStream failed (%s)\n", __func__,
393 			    ZSTD_getErrorName(rc));
394 			return (EIO);
395 		}
396 		if (lastpos == s->zst_outbuffer.pos) {
397 			printf("%s: did not make forward progress endStream %zu\n",
398 			    __func__, lastpos);
399 			return (EIO);
400 		}
401 
402 		error = zst_flush_intermediate(s, cb, arg);
403 		if (error != 0)
404 			return (error);
405 
406 		lastpos = s->zst_outbuffer.pos;
407 	}
408 
409 	/*
410 	 * We've already done an intermediate flush, so all full blocks have
411 	 * been written.  Only a partial block remains.  Padding happens in a
412 	 * higher layer.
413 	 */
414 	if (s->zst_outbuffer.pos != 0) {
415 		error = cb(s->zst_buffer, s->zst_outbuffer.pos, s->zst_off,
416 		    arg);
417 		if (error != 0)
418 			return (error);
419 	}
420 
421 	return (0);
422 }
423 
424 static int
425 zstdio_write(void *stream, void *data, size_t len, compressor_cb_t cb,
426     void *arg)
427 {
428 	struct zstdio_stream *s;
429 	size_t lastpos, rc;
430 	int error;
431 
432 	s = stream;
433 	if (data == NULL)
434 		return (zstdio_flush(s, cb, arg));
435 
436 	s->zst_inbuffer.src = data;
437 	s->zst_inbuffer.size = len;
438 	s->zst_inbuffer.pos = 0;
439 	lastpos = 0;
440 
441 	while (s->zst_inbuffer.pos < s->zst_inbuffer.size) {
442 		rc = ZSTD_compressStream(s->zst_stream, &s->zst_outbuffer,
443 		    &s->zst_inbuffer);
444 		if (ZSTD_isError(rc)) {
445 			printf("%s: Compress failed on %p! (%s)\n",
446 			    __func__, data, ZSTD_getErrorName(rc));
447 			return (EIO);
448 		}
449 
450 		if (lastpos == s->zst_inbuffer.pos) {
451 			/*
452 			 * XXX: May need flushStream to make forward progress
453 			 */
454 			printf("ZSTD: did not make forward progress @pos %zu\n",
455 			    lastpos);
456 			return (EIO);
457 		}
458 		lastpos = s->zst_inbuffer.pos;
459 
460 		error = zst_flush_intermediate(s, cb, arg);
461 		if (error != 0)
462 			return (error);
463 	}
464 	return (0);
465 }
466 
467 static void
468 zstdio_fini(void *stream)
469 {
470 	struct zstdio_stream *s;
471 
472 	s = stream;
473 	if (s->zst_static_wkspc != NULL)
474 		free(s->zst_static_wkspc, M_COMPRESS);
475 	else
476 		ZSTD_freeCCtx(s->zst_stream);
477 	free(s->zst_buffer, M_COMPRESS);
478 	free(s, M_COMPRESS);
479 }
480 
481 static struct compressor_methods zstd_methods = {
482 	.format = COMPRESS_ZSTD,
483 	.init = zstdio_init,
484 	.reset = zstdio_reset,
485 	.write = zstdio_write,
486 	.fini = zstdio_fini,
487 };
488 DATA_SET(compressors, zstd_methods);
489 
490 #endif /* ZSTDIO */
491 
492 bool
493 compressor_avail(int format)
494 {
495 	struct compressor_methods **iter;
496 
497 	SET_FOREACH(iter, compressors) {
498 		if ((*iter)->format == format)
499 			return (true);
500 	}
501 	return (false);
502 }
503 
504 struct compressor *
505 compressor_init(compressor_cb_t cb, int format, size_t maxiosize, int level,
506     void *arg)
507 {
508 	struct compressor_methods **iter;
509 	struct compressor *s;
510 	void *priv;
511 
512 	SET_FOREACH(iter, compressors) {
513 		if ((*iter)->format == format)
514 			break;
515 	}
516 	if (iter == SET_LIMIT(compressors))
517 		return (NULL);
518 
519 	priv = (*iter)->init(maxiosize, level);
520 	if (priv == NULL)
521 		return (NULL);
522 
523 	s = malloc(sizeof(*s), M_COMPRESS, M_WAITOK | M_ZERO);
524 	s->methods = (*iter);
525 	s->priv = priv;
526 	s->cb = cb;
527 	s->arg = arg;
528 	return (s);
529 }
530 
531 void
532 compressor_reset(struct compressor *stream)
533 {
534 
535 	stream->methods->reset(stream->priv);
536 }
537 
538 int
539 compressor_write(struct compressor *stream, void *data, size_t len)
540 {
541 
542 	return (stream->methods->write(stream->priv, data, len, stream->cb,
543 	    stream->arg));
544 }
545 
546 int
547 compressor_flush(struct compressor *stream)
548 {
549 
550 	return (stream->methods->write(stream->priv, NULL, 0, stream->cb,
551 	    stream->arg));
552 }
553 
554 void
555 compressor_fini(struct compressor *stream)
556 {
557 
558 	stream->methods->fini(stream->priv);
559 }
560