image.c revision 272775 
1/*-
2 * Copyright (c) 2014 Juniper Networks, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/10/usr.bin/mkimg/image.c 272775 2014-10-08 22:09:36Z marcel $");
29
30#include <sys/mman.h>
31#include <sys/queue.h>
32#include <sys/stat.h>
33#include <sys/types.h>
34#include <assert.h>
35#include <errno.h>
36#include <limits.h>
37#include <paths.h>
38#include <stdint.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <string.h>
42#include <unistd.h>
43
44#include "image.h"
45#include "mkimg.h"
46
47struct chunk {
48	STAILQ_ENTRY(chunk) ch_list;
49	size_t	ch_size;		/* Size of chunk in bytes. */
50	lba_t	ch_block;		/* Block address in image. */
51	union {
52		struct {
53			off_t	ofs;	/* Offset in backing file. */
54			int	fd;	/* FD of backing file. */
55		} file;
56		struct {
57			void	*ptr;	/* Pointer to data in memory */
58		} mem;
59	} ch_u;
60	u_int	ch_type;
61#define	CH_TYPE_ZEROES		0	/* Chunk is a gap (no data). */
62#define	CH_TYPE_FILE		1	/* File-backed chunk. */
63#define	CH_TYPE_MEMORY		2	/* Memory-backed chunk */
64};
65
66static STAILQ_HEAD(chunk_head, chunk) image_chunks;
67static u_int image_nchunks;
68
69static char image_swap_file[PATH_MAX];
70static int image_swap_fd = -1;
71static u_int image_swap_pgsz;
72static off_t image_swap_size;
73
74static lba_t image_size;
75
76static int
77is_empty_sector(void *buf)
78{
79	uint64_t *p = buf;
80	size_t n, max;
81
82	assert(((uintptr_t)p & 3) == 0);
83
84	max = secsz / sizeof(uint64_t);
85	for (n = 0; n < max; n++) {
86		if (p[n] != 0UL)
87			return (0);
88	}
89	return (1);
90}
91
92/*
93 * Swap file handlng.
94 */
95
96static off_t
97image_swap_alloc(size_t size)
98{
99	off_t ofs;
100	size_t unit;
101
102	unit = (secsz > image_swap_pgsz) ? secsz : image_swap_pgsz;
103	assert((unit & (unit - 1)) == 0);
104
105	size = (size + unit - 1) & ~(unit - 1);
106
107	ofs = image_swap_size;
108	image_swap_size += size;
109	if (ftruncate(image_swap_fd, image_swap_size) == -1) {
110		image_swap_size = ofs;
111		ofs = -1LL;
112	}
113	return (ofs);
114}
115
116/*
117 * Image chunk handling.
118 */
119
120static struct chunk *
121image_chunk_find(lba_t blk)
122{
123	static struct chunk *last = NULL;
124	struct chunk *ch;
125
126	ch = (last != NULL && last->ch_block <= blk)
127	    ? last : STAILQ_FIRST(&image_chunks);
128	while (ch != NULL) {
129		if (ch->ch_block <= blk &&
130		    (lba_t)(ch->ch_block + (ch->ch_size / secsz)) > blk) {
131			last = ch;
132			break;
133		}
134		ch = STAILQ_NEXT(ch, ch_list);
135	}
136	return (ch);
137}
138
139static size_t
140image_chunk_grow(struct chunk *ch, size_t sz)
141{
142	size_t dsz, newsz;
143
144	newsz = ch->ch_size + sz;
145	if (newsz > ch->ch_size) {
146		ch->ch_size = newsz;
147		return (0);
148	}
149	/* We would overflow -- create new chunk for remainder. */
150	dsz = SIZE_MAX - ch->ch_size;
151	assert(dsz < sz);
152	ch->ch_size = SIZE_MAX;
153	return (sz - dsz);
154}
155
156static struct chunk *
157image_chunk_memory(struct chunk *ch, lba_t blk)
158{
159	struct chunk *new;
160	void *ptr;
161
162	ptr = calloc(1, secsz);
163	if (ptr == NULL)
164		return (NULL);
165
166	if (ch->ch_block < blk) {
167		new = malloc(sizeof(*new));
168		if (new == NULL) {
169			free(ptr);
170			return (NULL);
171		}
172		memcpy(new, ch, sizeof(*new));
173		ch->ch_size = (blk - ch->ch_block) * secsz;
174		new->ch_block = blk;
175		new->ch_size -= ch->ch_size;
176		STAILQ_INSERT_AFTER(&image_chunks, ch, new, ch_list);
177		image_nchunks++;
178		ch = new;
179	}
180
181	if (ch->ch_size > secsz) {
182		new = malloc(sizeof(*new));
183		if (new == NULL) {
184			free(ptr);
185			return (NULL);
186		}
187		memcpy(new, ch, sizeof(*new));
188		ch->ch_size = secsz;
189		new->ch_block++;
190		new->ch_size -= secsz;
191		STAILQ_INSERT_AFTER(&image_chunks, ch, new, ch_list);
192		image_nchunks++;
193	}
194
195	ch->ch_type = CH_TYPE_MEMORY;
196	ch->ch_u.mem.ptr = ptr;
197	return (ch);
198}
199
200static int
201image_chunk_skipto(lba_t to)
202{
203	struct chunk *ch;
204	lba_t from;
205	size_t sz;
206
207	ch = STAILQ_LAST(&image_chunks, chunk, ch_list);
208	from = (ch != NULL) ? ch->ch_block + (ch->ch_size / secsz) : 0LL;
209
210	assert(from <= to);
211
212	/* Nothing to do? */
213	if (from == to)
214		return (0);
215	/* Avoid bugs due to overflows. */
216	if ((uintmax_t)(to - from) > (uintmax_t)(SIZE_MAX / secsz))
217		return (EFBIG);
218	sz = (to - from) * secsz;
219	if (ch != NULL && ch->ch_type == CH_TYPE_ZEROES) {
220		sz = image_chunk_grow(ch, sz);
221		if (sz == 0)
222			return (0);
223		from = ch->ch_block + (ch->ch_size / secsz);
224	}
225	ch = malloc(sizeof(*ch));
226	if (ch == NULL)
227		return (ENOMEM);
228	memset(ch, 0, sizeof(*ch));
229	ch->ch_block = from;
230	ch->ch_size = sz;
231	ch->ch_type = CH_TYPE_ZEROES;
232	STAILQ_INSERT_TAIL(&image_chunks, ch, ch_list);
233	image_nchunks++;
234	return (0);
235}
236
237static int
238image_chunk_append(lba_t blk, size_t sz, off_t ofs, int fd)
239{
240	struct chunk *ch;
241
242	ch = STAILQ_LAST(&image_chunks, chunk, ch_list);
243	if (ch != NULL && ch->ch_type == CH_TYPE_FILE) {
244		if (fd == ch->ch_u.file.fd &&
245		    blk == (lba_t)(ch->ch_block + (ch->ch_size / secsz)) &&
246		    ofs == (off_t)(ch->ch_u.file.ofs + ch->ch_size)) {
247			sz = image_chunk_grow(ch, sz);
248			if (sz == 0)
249				return (0);
250			blk = ch->ch_block + (ch->ch_size / secsz);
251			ofs = ch->ch_u.file.ofs + ch->ch_size;
252		}
253	}
254	ch = malloc(sizeof(*ch));
255	if (ch == NULL)
256		return (ENOMEM);
257	memset(ch, 0, sizeof(*ch));
258	ch->ch_block = blk;
259	ch->ch_size = sz;
260	ch->ch_type = CH_TYPE_FILE;
261	ch->ch_u.file.ofs = ofs;
262	ch->ch_u.file.fd = fd;
263	STAILQ_INSERT_TAIL(&image_chunks, ch, ch_list);
264	image_nchunks++;
265	return (0);
266}
267
268static int
269image_chunk_copyin(lba_t blk, void *buf, size_t sz, off_t ofs, int fd)
270{
271	uint8_t *p = buf;
272	int error;
273
274	error = 0;
275	sz = (sz + secsz - 1) & ~(secsz - 1);
276	while (!error && sz > 0) {
277		if (is_empty_sector(p))
278			error = image_chunk_skipto(blk + 1);
279		else
280			error = image_chunk_append(blk, secsz, ofs, fd);
281		blk++;
282		p += secsz;
283		sz -= secsz;
284		ofs += secsz;
285	}
286	return (error);
287}
288
289/*
290 * File mapping support.
291 */
292
293static void *
294image_file_map(int fd, off_t ofs, size_t sz)
295{
296	void *ptr;
297	size_t unit;
298	int flags, prot;
299
300	unit = (secsz > image_swap_pgsz) ? secsz : image_swap_pgsz;
301	assert((unit & (unit - 1)) == 0);
302
303	flags = MAP_NOCORE | MAP_NOSYNC | MAP_SHARED;
304	/* Allow writing to our swap file only. */
305	prot = PROT_READ | ((fd == image_swap_fd) ? PROT_WRITE : 0);
306	sz = (sz + unit - 1) & ~(unit - 1);
307	ptr = mmap(NULL, sz, prot, flags, fd, ofs);
308	return ((ptr == MAP_FAILED) ? NULL : ptr);
309}
310
311static int
312image_file_unmap(void *buffer, size_t sz)
313{
314	size_t unit;
315
316	unit = (secsz > image_swap_pgsz) ? secsz : image_swap_pgsz;
317	sz = (sz + unit - 1) & ~(unit - 1);
318	munmap(buffer, sz);
319	return (0);
320}
321
322/*
323 * Input/source file handling.
324 */
325
326static int
327image_copyin_stream(lba_t blk, int fd, uint64_t *sizep)
328{
329	char *buffer;
330	uint64_t bytesize;
331	off_t swofs;
332	size_t iosz;
333	ssize_t rdsz;
334	int error;
335
336	/*
337	 * This makes sure we're doing I/O in multiples of the page
338	 * size as well as of the sector size. 2MB is the minimum
339	 * by virtue of secsz at least 512 bytes and the page size
340	 * at least 4K bytes.
341	 */
342	iosz = secsz * image_swap_pgsz;
343
344	bytesize = 0;
345	do {
346		swofs = image_swap_alloc(iosz);
347		if (swofs == -1LL)
348			return (errno);
349		buffer = image_file_map(image_swap_fd, swofs, iosz);
350		if (buffer == NULL)
351			return (errno);
352		rdsz = read(fd, buffer, iosz);
353		if (rdsz > 0)
354			error = image_chunk_copyin(blk, buffer, rdsz, swofs,
355			    image_swap_fd);
356		else if (rdsz < 0)
357			error = errno;
358		else
359			error = 0;
360		image_file_unmap(buffer, iosz);
361		/* XXX should we relinguish unused swap space? */
362		if (error)
363			return (error);
364
365		bytesize += rdsz;
366		blk += (rdsz + secsz - 1) / secsz;
367	} while (rdsz > 0);
368
369	if (sizep != NULL)
370		*sizep = bytesize;
371	return (0);
372}
373
374static int
375image_copyin_mapped(lba_t blk, int fd, uint64_t *sizep)
376{
377	off_t cur, data, end, hole, pos;
378	void *buf;
379	uint64_t bytesize;
380	size_t iosz, sz;
381	int error;
382
383	/*
384	 * We'd like to know the size of the file and we must
385	 * be able to seek in order to mmap(2). If this isn't
386	 * possible, then treat the file as a stream/pipe.
387	 */
388	end = lseek(fd, 0L, SEEK_END);
389	if (end == -1L)
390		return (image_copyin_stream(blk, fd, sizep));
391
392	/*
393	 * We need the file opened for the duration and our
394	 * caller is going to close the file. Make a dup(2)
395	 * so that control the faith of the descriptor.
396	 */
397	fd = dup(fd);
398	if (fd == -1)
399		return (errno);
400
401	iosz = secsz * image_swap_pgsz;
402
403	bytesize = 0;
404	cur = pos = 0;
405	error = 0;
406	while (!error && cur < end) {
407		hole = lseek(fd, cur, SEEK_HOLE);
408		data = lseek(fd, cur, SEEK_DATA);
409
410		/*
411		 * Treat the entire file as data if sparse files
412		 * are not supported by the underlying file system.
413		 */
414		if (hole == -1 && data == -1) {
415			data = cur;
416			hole = end;
417		}
418
419		if (cur == hole && data > hole) {
420			hole = pos;
421			pos = data & ~((uint64_t)secsz - 1);
422
423			blk += (pos - hole) / secsz;
424			error = image_chunk_skipto(blk);
425
426			bytesize += pos - hole;
427			cur = data;
428		} else if (cur == data && hole > data) {
429			data = pos;
430			pos = (hole + secsz - 1) & ~((uint64_t)secsz - 1);
431
432			while (data < pos) {
433				sz = (pos - data > (off_t)iosz)
434				    ? iosz : (size_t)(pos - data);
435
436				buf = image_file_map(fd, data, sz);
437				if (buf != NULL) {
438					error = image_chunk_copyin(blk, buf,
439					    sz, data, fd);
440					image_file_unmap(buf, sz);
441				} else
442					error = errno;
443
444				blk += sz / secsz;
445				bytesize += sz;
446				data += sz;
447			}
448			cur = hole;
449		} else {
450			/*
451			 * I don't know what this means or whether it
452			 * can happen at all...
453			 */
454			error = EDOOFUS;
455			break;
456		}
457	}
458	if (error)
459		close(fd);
460	if (!error && sizep != NULL)
461		*sizep = bytesize;
462	return (error);
463}
464
465int
466image_copyin(lba_t blk, int fd, uint64_t *sizep)
467{
468	struct stat sb;
469	int error;
470
471	error = image_chunk_skipto(blk);
472	if (!error) {
473		if (fstat(fd, &sb) == -1 || !S_ISREG(sb.st_mode))
474			error = image_copyin_stream(blk, fd, sizep);
475		else
476			error = image_copyin_mapped(blk, fd, sizep);
477	}
478	return (error);
479}
480
481/*
482 * Output/sink file handling.
483 */
484
485int
486image_copyout(int fd)
487{
488	int error;
489
490	error = image_copyout_region(fd, 0, image_size);
491	if (!error)
492		error = image_copyout_done(fd);
493	return (error);
494}
495
496int
497image_copyout_done(int fd)
498{
499	off_t ofs;
500	int error;
501
502	ofs = lseek(fd, 0L, SEEK_CUR);
503	if (ofs == -1)
504		return (0);
505	error = (ftruncate(fd, ofs) == -1) ? errno : 0;
506	return (error);
507}
508
509static int
510image_copyout_memory(int fd, size_t size, void *ptr)
511{
512
513	if (write(fd, ptr, size) == -1)
514		return (errno);
515	return (0);
516}
517
518static int
519image_copyout_zeroes(int fd, size_t size)
520{
521	static uint8_t *zeroes = NULL;
522	size_t sz;
523	int error;
524
525	if (lseek(fd, (off_t)size, SEEK_CUR) != -1)
526		return (0);
527
528	/*
529	 * If we can't seek, we must write.
530	 */
531
532	if (zeroes == NULL) {
533		zeroes = calloc(1, secsz);
534		if (zeroes == NULL)
535			return (ENOMEM);
536	}
537
538	while (size > 0) {
539		sz = (size > secsz) ? secsz : size;
540		error = image_copyout_memory(fd, sz, zeroes);
541		if (error)
542			return (error);
543		size -= sz;
544	}
545	return (0);
546}
547
548static int
549image_copyout_file(int fd, size_t size, int ifd, off_t iofs)
550{
551	void *buf;
552	size_t iosz, sz;
553	int error;
554
555	iosz = secsz * image_swap_pgsz;
556
557	while (size > 0) {
558		sz = (size > iosz) ? iosz : size;
559		buf = image_file_map(ifd, iofs, sz);
560		if (buf == NULL)
561			return (errno);
562		error = image_copyout_memory(fd, sz, buf);
563		image_file_unmap(buf, sz);
564		if (error)
565			return (error);
566		size -= sz;
567		iofs += sz;
568	}
569	return (0);
570}
571
572int
573image_copyout_region(int fd, lba_t blk, lba_t size)
574{
575	struct chunk *ch;
576	size_t ofs, sz;
577	int error;
578
579	size *= secsz;
580
581	while (size > 0) {
582		ch = image_chunk_find(blk);
583		if (ch == NULL)
584			return (EINVAL);
585		ofs = (blk - ch->ch_block) * secsz;
586		sz = ch->ch_size - ofs;
587		sz = ((lba_t)sz < size) ? sz : (size_t)size;
588		switch (ch->ch_type) {
589		case CH_TYPE_ZEROES:
590			error = image_copyout_zeroes(fd, sz);
591			break;
592		case CH_TYPE_FILE:
593			error = image_copyout_file(fd, sz, ch->ch_u.file.fd,
594			    ch->ch_u.file.ofs + ofs);
595			break;
596		case CH_TYPE_MEMORY:
597			error = image_copyout_memory(fd, sz, ch->ch_u.mem.ptr);
598			break;
599		default:
600			return (EDOOFUS);
601		}
602		size -= sz;
603		blk += sz / secsz;
604	}
605	return (0);
606}
607
608int
609image_data(lba_t blk, lba_t size)
610{
611	struct chunk *ch;
612	lba_t lim;
613
614	while (1) {
615		ch = image_chunk_find(blk);
616		if (ch == NULL)
617			return (0);
618		if (ch->ch_type != CH_TYPE_ZEROES)
619			return (1);
620		lim = ch->ch_block + (ch->ch_size / secsz);
621		if (lim >= blk + size)
622			return (0);
623		size -= lim - blk;
624		blk = lim;
625	}
626	/*NOTREACHED*/
627}
628
629lba_t
630image_get_size(void)
631{
632
633	return (image_size);
634}
635
636int
637image_set_size(lba_t blk)
638{
639	int error;
640
641	error = image_chunk_skipto(blk);
642	if (!error)
643		image_size = blk;
644	return (error);
645}
646
647int
648image_write(lba_t blk, void *buf, ssize_t len)
649{
650	struct chunk *ch;
651
652	while (len > 0) {
653		if (!is_empty_sector(buf)) {
654			ch = image_chunk_find(blk);
655			if (ch == NULL)
656				return (ENXIO);
657			/* We may not be able to write to files. */
658			if (ch->ch_type == CH_TYPE_FILE)
659				return (EINVAL);
660			if (ch->ch_type == CH_TYPE_ZEROES) {
661				ch = image_chunk_memory(ch, blk);
662				if (ch == NULL)
663					return (ENOMEM);
664			}
665			assert(ch->ch_type == CH_TYPE_MEMORY);
666			memcpy(ch->ch_u.mem.ptr, buf, secsz);
667		}
668		blk++;
669		buf = (char *)buf + secsz;
670		len--;
671	}
672	return (0);
673}
674
675static void
676image_cleanup(void)
677{
678	struct chunk *ch;
679
680	while ((ch = STAILQ_FIRST(&image_chunks)) != NULL) {
681		switch (ch->ch_type) {
682		case CH_TYPE_FILE:
683			/* We may be closing the same file multiple times. */
684			if (ch->ch_u.file.fd != -1)
685				close(ch->ch_u.file.fd);
686			break;
687		case CH_TYPE_MEMORY:
688			free(ch->ch_u.mem.ptr);
689			break;
690		default:
691			break;
692		}
693		STAILQ_REMOVE_HEAD(&image_chunks, ch_list);
694		free(ch);
695	}
696	if (image_swap_fd != -1)
697		close(image_swap_fd);
698	unlink(image_swap_file);
699}
700
701int
702image_init(void)
703{
704	const char *tmpdir;
705
706	STAILQ_INIT(&image_chunks);
707	image_nchunks = 0;
708
709	image_swap_size = 0;
710	image_swap_pgsz = getpagesize();
711
712	if (atexit(image_cleanup) == -1)
713		return (errno);
714	if ((tmpdir = getenv("TMPDIR")) == NULL || *tmpdir == '\0')
715		tmpdir = _PATH_TMP;
716	snprintf(image_swap_file, sizeof(image_swap_file), "%s/mkimg-XXXXXX",
717	    tmpdir);
718	image_swap_fd = mkstemp(image_swap_file);
719	if (image_swap_fd == -1)
720		return (errno);
721	return (0);
722}
723