xref: /qemu/qemu-img.c (revision 59427871)
1 /*
2  * QEMU disk image utility
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 #include "qapi-visit.h"
25 #include "qapi/qmp-output-visitor.h"
26 #include "qapi/qmp/qjson.h"
27 #include "qemu-common.h"
28 #include "qemu/option.h"
29 #include "qemu/error-report.h"
30 #include "qemu/osdep.h"
31 #include "sysemu/sysemu.h"
32 #include "block/block_int.h"
33 #include "block/qapi.h"
34 #include <getopt.h>
35 #include <stdio.h>
36 #include <stdarg.h>
37 
38 #ifdef _WIN32
39 #include <windows.h>
40 #endif
41 
42 typedef struct img_cmd_t {
43     const char *name;
44     int (*handler)(int argc, char **argv);
45 } img_cmd_t;
46 
47 enum {
48     OPTION_OUTPUT = 256,
49     OPTION_BACKING_CHAIN = 257,
50 };
51 
52 typedef enum OutputFormat {
53     OFORMAT_JSON,
54     OFORMAT_HUMAN,
55 } OutputFormat;
56 
57 /* Default to cache=writeback as data integrity is not important for qemu-tcg. */
58 #define BDRV_O_FLAGS BDRV_O_CACHE_WB
59 #define BDRV_DEFAULT_CACHE "writeback"
60 
61 static void format_print(void *opaque, const char *name)
62 {
63     printf(" %s", name);
64 }
65 
66 /* Please keep in synch with qemu-img.texi */
67 static void help(void)
68 {
69     const char *help_msg =
70            "qemu-img version " QEMU_VERSION ", Copyright (c) 2004-2008 Fabrice Bellard\n"
71            "usage: qemu-img command [command options]\n"
72            "QEMU disk image utility\n"
73            "\n"
74            "Command syntax:\n"
75 #define DEF(option, callback, arg_string)        \
76            "  " arg_string "\n"
77 #include "qemu-img-cmds.h"
78 #undef DEF
79 #undef GEN_DOCS
80            "\n"
81            "Command parameters:\n"
82            "  'filename' is a disk image filename\n"
83            "  'fmt' is the disk image format. It is guessed automatically in most cases\n"
84            "  'cache' is the cache mode used to write the output disk image, the valid\n"
85            "    options are: 'none', 'writeback' (default, except for convert), 'writethrough',\n"
86            "    'directsync' and 'unsafe' (default for convert)\n"
87            "  'size' is the disk image size in bytes. Optional suffixes\n"
88            "    'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G' (gigabyte, 1024M),\n"
89            "    'T' (terabyte, 1024G), 'P' (petabyte, 1024T) and 'E' (exabyte, 1024P)  are\n"
90            "    supported. 'b' is ignored.\n"
91            "  'output_filename' is the destination disk image filename\n"
92            "  'output_fmt' is the destination format\n"
93            "  'options' is a comma separated list of format specific options in a\n"
94            "    name=value format. Use -o ? for an overview of the options supported by the\n"
95            "    used format\n"
96            "  'snapshot_param' is param used for internal snapshot, format\n"
97            "    is 'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
98            "    '[ID_OR_NAME]'\n"
99            "  'snapshot_id_or_name' is deprecated, use 'snapshot_param'\n"
100            "    instead\n"
101            "  '-c' indicates that target image must be compressed (qcow format only)\n"
102            "  '-u' enables unsafe rebasing. It is assumed that old and new backing file\n"
103            "       match exactly. The image doesn't need a working backing file before\n"
104            "       rebasing in this case (useful for renaming the backing file)\n"
105            "  '-h' with or without a command shows this help and lists the supported formats\n"
106            "  '-p' show progress of command (only certain commands)\n"
107            "  '-q' use Quiet mode - do not print any output (except errors)\n"
108            "  '-S' indicates the consecutive number of bytes (defaults to 4k) that must\n"
109            "       contain only zeros for qemu-img to create a sparse image during\n"
110            "       conversion. If the number of bytes is 0, the source will not be scanned for\n"
111            "       unallocated or zero sectors, and the destination image will always be\n"
112            "       fully allocated\n"
113            "  '--output' takes the format in which the output must be done (human or json)\n"
114            "  '-n' skips the target volume creation (useful if the volume is created\n"
115            "       prior to running qemu-img)\n"
116            "\n"
117            "Parameters to check subcommand:\n"
118            "  '-r' tries to repair any inconsistencies that are found during the check.\n"
119            "       '-r leaks' repairs only cluster leaks, whereas '-r all' fixes all\n"
120            "       kinds of errors, with a higher risk of choosing the wrong fix or\n"
121            "       hiding corruption that has already occurred.\n"
122            "\n"
123            "Parameters to snapshot subcommand:\n"
124            "  'snapshot' is the name of the snapshot to create, apply or delete\n"
125            "  '-a' applies a snapshot (revert disk to saved state)\n"
126            "  '-c' creates a snapshot\n"
127            "  '-d' deletes a snapshot\n"
128            "  '-l' lists all snapshots in the given image\n"
129            "\n"
130            "Parameters to compare subcommand:\n"
131            "  '-f' first image format\n"
132            "  '-F' second image format\n"
133            "  '-s' run in Strict mode - fail on different image size or sector allocation\n";
134 
135     printf("%s\nSupported formats:", help_msg);
136     bdrv_iterate_format(format_print, NULL);
137     printf("\n");
138     exit(1);
139 }
140 
141 static int GCC_FMT_ATTR(2, 3) qprintf(bool quiet, const char *fmt, ...)
142 {
143     int ret = 0;
144     if (!quiet) {
145         va_list args;
146         va_start(args, fmt);
147         ret = vprintf(fmt, args);
148         va_end(args);
149     }
150     return ret;
151 }
152 
153 #if defined(WIN32)
154 /* XXX: put correct support for win32 */
155 static int read_password(char *buf, int buf_size)
156 {
157     int c, i;
158     printf("Password: ");
159     fflush(stdout);
160     i = 0;
161     for(;;) {
162         c = getchar();
163         if (c == '\n')
164             break;
165         if (i < (buf_size - 1))
166             buf[i++] = c;
167     }
168     buf[i] = '\0';
169     return 0;
170 }
171 
172 #else
173 
174 #include <termios.h>
175 
176 static struct termios oldtty;
177 
178 static void term_exit(void)
179 {
180     tcsetattr (0, TCSANOW, &oldtty);
181 }
182 
183 static void term_init(void)
184 {
185     struct termios tty;
186 
187     tcgetattr (0, &tty);
188     oldtty = tty;
189 
190     tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
191                           |INLCR|IGNCR|ICRNL|IXON);
192     tty.c_oflag |= OPOST;
193     tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
194     tty.c_cflag &= ~(CSIZE|PARENB);
195     tty.c_cflag |= CS8;
196     tty.c_cc[VMIN] = 1;
197     tty.c_cc[VTIME] = 0;
198 
199     tcsetattr (0, TCSANOW, &tty);
200 
201     atexit(term_exit);
202 }
203 
204 static int read_password(char *buf, int buf_size)
205 {
206     uint8_t ch;
207     int i, ret;
208 
209     printf("password: ");
210     fflush(stdout);
211     term_init();
212     i = 0;
213     for(;;) {
214         ret = read(0, &ch, 1);
215         if (ret == -1) {
216             if (errno == EAGAIN || errno == EINTR) {
217                 continue;
218             } else {
219                 ret = -1;
220                 break;
221             }
222         } else if (ret == 0) {
223             ret = -1;
224             break;
225         } else {
226             if (ch == '\r') {
227                 ret = 0;
228                 break;
229             }
230             if (i < (buf_size - 1))
231                 buf[i++] = ch;
232         }
233     }
234     term_exit();
235     buf[i] = '\0';
236     printf("\n");
237     return ret;
238 }
239 #endif
240 
241 static int print_block_option_help(const char *filename, const char *fmt)
242 {
243     BlockDriver *drv, *proto_drv;
244     QEMUOptionParameter *create_options = NULL;
245 
246     /* Find driver and parse its options */
247     drv = bdrv_find_format(fmt);
248     if (!drv) {
249         error_report("Unknown file format '%s'", fmt);
250         return 1;
251     }
252 
253     proto_drv = bdrv_find_protocol(filename, true);
254     if (!proto_drv) {
255         error_report("Unknown protocol '%s'", filename);
256         return 1;
257     }
258 
259     create_options = append_option_parameters(create_options,
260                                               drv->create_options);
261     create_options = append_option_parameters(create_options,
262                                               proto_drv->create_options);
263     print_option_help(create_options);
264     free_option_parameters(create_options);
265     return 0;
266 }
267 
268 static BlockDriverState *bdrv_new_open(const char *filename,
269                                        const char *fmt,
270                                        int flags,
271                                        bool require_io,
272                                        bool quiet)
273 {
274     BlockDriverState *bs;
275     BlockDriver *drv;
276     char password[256];
277     Error *local_err = NULL;
278     int ret;
279 
280     bs = bdrv_new("image");
281 
282     if (fmt) {
283         drv = bdrv_find_format(fmt);
284         if (!drv) {
285             error_report("Unknown file format '%s'", fmt);
286             goto fail;
287         }
288     } else {
289         drv = NULL;
290     }
291 
292     ret = bdrv_open(bs, filename, NULL, flags, drv, &local_err);
293     if (ret < 0) {
294         error_report("Could not open '%s': %s", filename,
295                      error_get_pretty(local_err));
296         error_free(local_err);
297         goto fail;
298     }
299 
300     if (bdrv_is_encrypted(bs) && require_io) {
301         qprintf(quiet, "Disk image '%s' is encrypted.\n", filename);
302         if (read_password(password, sizeof(password)) < 0) {
303             error_report("No password given");
304             goto fail;
305         }
306         if (bdrv_set_key(bs, password) < 0) {
307             error_report("invalid password");
308             goto fail;
309         }
310     }
311     return bs;
312 fail:
313     if (bs) {
314         bdrv_unref(bs);
315     }
316     return NULL;
317 }
318 
319 static int add_old_style_options(const char *fmt, QEMUOptionParameter *list,
320                                  const char *base_filename,
321                                  const char *base_fmt)
322 {
323     if (base_filename) {
324         if (set_option_parameter(list, BLOCK_OPT_BACKING_FILE, base_filename)) {
325             error_report("Backing file not supported for file format '%s'",
326                          fmt);
327             return -1;
328         }
329     }
330     if (base_fmt) {
331         if (set_option_parameter(list, BLOCK_OPT_BACKING_FMT, base_fmt)) {
332             error_report("Backing file format not supported for file "
333                          "format '%s'", fmt);
334             return -1;
335         }
336     }
337     return 0;
338 }
339 
340 static int img_create(int argc, char **argv)
341 {
342     int c;
343     uint64_t img_size = -1;
344     const char *fmt = "raw";
345     const char *base_fmt = NULL;
346     const char *filename;
347     const char *base_filename = NULL;
348     char *options = NULL;
349     Error *local_err = NULL;
350     bool quiet = false;
351 
352     for(;;) {
353         c = getopt(argc, argv, "F:b:f:he6o:q");
354         if (c == -1) {
355             break;
356         }
357         switch(c) {
358         case '?':
359         case 'h':
360             help();
361             break;
362         case 'F':
363             base_fmt = optarg;
364             break;
365         case 'b':
366             base_filename = optarg;
367             break;
368         case 'f':
369             fmt = optarg;
370             break;
371         case 'e':
372             error_report("option -e is deprecated, please use \'-o "
373                   "encryption\' instead!");
374             return 1;
375         case '6':
376             error_report("option -6 is deprecated, please use \'-o "
377                   "compat6\' instead!");
378             return 1;
379         case 'o':
380             options = optarg;
381             break;
382         case 'q':
383             quiet = true;
384             break;
385         }
386     }
387 
388     /* Get the filename */
389     if (optind >= argc) {
390         help();
391     }
392     filename = argv[optind++];
393 
394     /* Get image size, if specified */
395     if (optind < argc) {
396         int64_t sval;
397         char *end;
398         sval = strtosz_suffix(argv[optind++], &end, STRTOSZ_DEFSUFFIX_B);
399         if (sval < 0 || *end) {
400             if (sval == -ERANGE) {
401                 error_report("Image size must be less than 8 EiB!");
402             } else {
403                 error_report("Invalid image size specified! You may use k, M, "
404                       "G, T, P or E suffixes for ");
405                 error_report("kilobytes, megabytes, gigabytes, terabytes, "
406                              "petabytes and exabytes.");
407             }
408             return 1;
409         }
410         img_size = (uint64_t)sval;
411     }
412     if (optind != argc) {
413         help();
414     }
415 
416     if (options && is_help_option(options)) {
417         return print_block_option_help(filename, fmt);
418     }
419 
420     bdrv_img_create(filename, fmt, base_filename, base_fmt,
421                     options, img_size, BDRV_O_FLAGS, &local_err, quiet);
422     if (error_is_set(&local_err)) {
423         error_report("%s: %s", filename, error_get_pretty(local_err));
424         error_free(local_err);
425         return 1;
426     }
427 
428     return 0;
429 }
430 
431 static void dump_json_image_check(ImageCheck *check, bool quiet)
432 {
433     Error *errp = NULL;
434     QString *str;
435     QmpOutputVisitor *ov = qmp_output_visitor_new();
436     QObject *obj;
437     visit_type_ImageCheck(qmp_output_get_visitor(ov),
438                           &check, NULL, &errp);
439     obj = qmp_output_get_qobject(ov);
440     str = qobject_to_json_pretty(obj);
441     assert(str != NULL);
442     qprintf(quiet, "%s\n", qstring_get_str(str));
443     qobject_decref(obj);
444     qmp_output_visitor_cleanup(ov);
445     QDECREF(str);
446 }
447 
448 static void dump_human_image_check(ImageCheck *check, bool quiet)
449 {
450     if (!(check->corruptions || check->leaks || check->check_errors)) {
451         qprintf(quiet, "No errors were found on the image.\n");
452     } else {
453         if (check->corruptions) {
454             qprintf(quiet, "\n%" PRId64 " errors were found on the image.\n"
455                     "Data may be corrupted, or further writes to the image "
456                     "may corrupt it.\n",
457                     check->corruptions);
458         }
459 
460         if (check->leaks) {
461             qprintf(quiet,
462                     "\n%" PRId64 " leaked clusters were found on the image.\n"
463                     "This means waste of disk space, but no harm to data.\n",
464                     check->leaks);
465         }
466 
467         if (check->check_errors) {
468             qprintf(quiet,
469                     "\n%" PRId64
470                     " internal errors have occurred during the check.\n",
471                     check->check_errors);
472         }
473     }
474 
475     if (check->total_clusters != 0 && check->allocated_clusters != 0) {
476         qprintf(quiet, "%" PRId64 "/%" PRId64 " = %0.2f%% allocated, "
477                 "%0.2f%% fragmented, %0.2f%% compressed clusters\n",
478                 check->allocated_clusters, check->total_clusters,
479                 check->allocated_clusters * 100.0 / check->total_clusters,
480                 check->fragmented_clusters * 100.0 / check->allocated_clusters,
481                 check->compressed_clusters * 100.0 /
482                 check->allocated_clusters);
483     }
484 
485     if (check->image_end_offset) {
486         qprintf(quiet,
487                 "Image end offset: %" PRId64 "\n", check->image_end_offset);
488     }
489 }
490 
491 static int collect_image_check(BlockDriverState *bs,
492                    ImageCheck *check,
493                    const char *filename,
494                    const char *fmt,
495                    int fix)
496 {
497     int ret;
498     BdrvCheckResult result;
499 
500     ret = bdrv_check(bs, &result, fix);
501     if (ret < 0) {
502         return ret;
503     }
504 
505     check->filename                 = g_strdup(filename);
506     check->format                   = g_strdup(bdrv_get_format_name(bs));
507     check->check_errors             = result.check_errors;
508     check->corruptions              = result.corruptions;
509     check->has_corruptions          = result.corruptions != 0;
510     check->leaks                    = result.leaks;
511     check->has_leaks                = result.leaks != 0;
512     check->corruptions_fixed        = result.corruptions_fixed;
513     check->has_corruptions_fixed    = result.corruptions != 0;
514     check->leaks_fixed              = result.leaks_fixed;
515     check->has_leaks_fixed          = result.leaks != 0;
516     check->image_end_offset         = result.image_end_offset;
517     check->has_image_end_offset     = result.image_end_offset != 0;
518     check->total_clusters           = result.bfi.total_clusters;
519     check->has_total_clusters       = result.bfi.total_clusters != 0;
520     check->allocated_clusters       = result.bfi.allocated_clusters;
521     check->has_allocated_clusters   = result.bfi.allocated_clusters != 0;
522     check->fragmented_clusters      = result.bfi.fragmented_clusters;
523     check->has_fragmented_clusters  = result.bfi.fragmented_clusters != 0;
524     check->compressed_clusters      = result.bfi.compressed_clusters;
525     check->has_compressed_clusters  = result.bfi.compressed_clusters != 0;
526 
527     return 0;
528 }
529 
530 /*
531  * Checks an image for consistency. Exit codes:
532  *
533  * 0 - Check completed, image is good
534  * 1 - Check not completed because of internal errors
535  * 2 - Check completed, image is corrupted
536  * 3 - Check completed, image has leaked clusters, but is good otherwise
537  */
538 static int img_check(int argc, char **argv)
539 {
540     int c, ret;
541     OutputFormat output_format = OFORMAT_HUMAN;
542     const char *filename, *fmt, *output;
543     BlockDriverState *bs;
544     int fix = 0;
545     int flags = BDRV_O_FLAGS | BDRV_O_CHECK;
546     ImageCheck *check;
547     bool quiet = false;
548 
549     fmt = NULL;
550     output = NULL;
551     for(;;) {
552         int option_index = 0;
553         static const struct option long_options[] = {
554             {"help", no_argument, 0, 'h'},
555             {"format", required_argument, 0, 'f'},
556             {"repair", no_argument, 0, 'r'},
557             {"output", required_argument, 0, OPTION_OUTPUT},
558             {0, 0, 0, 0}
559         };
560         c = getopt_long(argc, argv, "f:hr:q",
561                         long_options, &option_index);
562         if (c == -1) {
563             break;
564         }
565         switch(c) {
566         case '?':
567         case 'h':
568             help();
569             break;
570         case 'f':
571             fmt = optarg;
572             break;
573         case 'r':
574             flags |= BDRV_O_RDWR;
575 
576             if (!strcmp(optarg, "leaks")) {
577                 fix = BDRV_FIX_LEAKS;
578             } else if (!strcmp(optarg, "all")) {
579                 fix = BDRV_FIX_LEAKS | BDRV_FIX_ERRORS;
580             } else {
581                 help();
582             }
583             break;
584         case OPTION_OUTPUT:
585             output = optarg;
586             break;
587         case 'q':
588             quiet = true;
589             break;
590         }
591     }
592     if (optind != argc - 1) {
593         help();
594     }
595     filename = argv[optind++];
596 
597     if (output && !strcmp(output, "json")) {
598         output_format = OFORMAT_JSON;
599     } else if (output && !strcmp(output, "human")) {
600         output_format = OFORMAT_HUMAN;
601     } else if (output) {
602         error_report("--output must be used with human or json as argument.");
603         return 1;
604     }
605 
606     bs = bdrv_new_open(filename, fmt, flags, true, quiet);
607     if (!bs) {
608         return 1;
609     }
610 
611     check = g_new0(ImageCheck, 1);
612     ret = collect_image_check(bs, check, filename, fmt, fix);
613 
614     if (ret == -ENOTSUP) {
615         if (output_format == OFORMAT_HUMAN) {
616             error_report("This image format does not support checks");
617         }
618         ret = 63;
619         goto fail;
620     }
621 
622     if (check->corruptions_fixed || check->leaks_fixed) {
623         int corruptions_fixed, leaks_fixed;
624 
625         leaks_fixed         = check->leaks_fixed;
626         corruptions_fixed   = check->corruptions_fixed;
627 
628         if (output_format == OFORMAT_HUMAN) {
629             qprintf(quiet,
630                     "The following inconsistencies were found and repaired:\n\n"
631                     "    %" PRId64 " leaked clusters\n"
632                     "    %" PRId64 " corruptions\n\n"
633                     "Double checking the fixed image now...\n",
634                     check->leaks_fixed,
635                     check->corruptions_fixed);
636         }
637 
638         ret = collect_image_check(bs, check, filename, fmt, 0);
639 
640         check->leaks_fixed          = leaks_fixed;
641         check->corruptions_fixed    = corruptions_fixed;
642     }
643 
644     switch (output_format) {
645     case OFORMAT_HUMAN:
646         dump_human_image_check(check, quiet);
647         break;
648     case OFORMAT_JSON:
649         dump_json_image_check(check, quiet);
650         break;
651     }
652 
653     if (ret || check->check_errors) {
654         ret = 1;
655         goto fail;
656     }
657 
658     if (check->corruptions) {
659         ret = 2;
660     } else if (check->leaks) {
661         ret = 3;
662     } else {
663         ret = 0;
664     }
665 
666 fail:
667     qapi_free_ImageCheck(check);
668     bdrv_unref(bs);
669 
670     return ret;
671 }
672 
673 static int img_commit(int argc, char **argv)
674 {
675     int c, ret, flags;
676     const char *filename, *fmt, *cache;
677     BlockDriverState *bs;
678     bool quiet = false;
679 
680     fmt = NULL;
681     cache = BDRV_DEFAULT_CACHE;
682     for(;;) {
683         c = getopt(argc, argv, "f:ht:q");
684         if (c == -1) {
685             break;
686         }
687         switch(c) {
688         case '?':
689         case 'h':
690             help();
691             break;
692         case 'f':
693             fmt = optarg;
694             break;
695         case 't':
696             cache = optarg;
697             break;
698         case 'q':
699             quiet = true;
700             break;
701         }
702     }
703     if (optind != argc - 1) {
704         help();
705     }
706     filename = argv[optind++];
707 
708     flags = BDRV_O_RDWR;
709     ret = bdrv_parse_cache_flags(cache, &flags);
710     if (ret < 0) {
711         error_report("Invalid cache option: %s", cache);
712         return -1;
713     }
714 
715     bs = bdrv_new_open(filename, fmt, flags, true, quiet);
716     if (!bs) {
717         return 1;
718     }
719     ret = bdrv_commit(bs);
720     switch(ret) {
721     case 0:
722         qprintf(quiet, "Image committed.\n");
723         break;
724     case -ENOENT:
725         error_report("No disk inserted");
726         break;
727     case -EACCES:
728         error_report("Image is read-only");
729         break;
730     case -ENOTSUP:
731         error_report("Image is already committed");
732         break;
733     default:
734         error_report("Error while committing image");
735         break;
736     }
737 
738     bdrv_unref(bs);
739     if (ret) {
740         return 1;
741     }
742     return 0;
743 }
744 
745 /*
746  * Returns true iff the first sector pointed to by 'buf' contains at least
747  * a non-NUL byte.
748  *
749  * 'pnum' is set to the number of sectors (including and immediately following
750  * the first one) that are known to be in the same allocated/unallocated state.
751  */
752 static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum)
753 {
754     bool is_zero;
755     int i;
756 
757     if (n <= 0) {
758         *pnum = 0;
759         return 0;
760     }
761     is_zero = buffer_is_zero(buf, 512);
762     for(i = 1; i < n; i++) {
763         buf += 512;
764         if (is_zero != buffer_is_zero(buf, 512)) {
765             break;
766         }
767     }
768     *pnum = i;
769     return !is_zero;
770 }
771 
772 /*
773  * Like is_allocated_sectors, but if the buffer starts with a used sector,
774  * up to 'min' consecutive sectors containing zeros are ignored. This avoids
775  * breaking up write requests for only small sparse areas.
776  */
777 static int is_allocated_sectors_min(const uint8_t *buf, int n, int *pnum,
778     int min)
779 {
780     int ret;
781     int num_checked, num_used;
782 
783     if (n < min) {
784         min = n;
785     }
786 
787     ret = is_allocated_sectors(buf, n, pnum);
788     if (!ret) {
789         return ret;
790     }
791 
792     num_used = *pnum;
793     buf += BDRV_SECTOR_SIZE * *pnum;
794     n -= *pnum;
795     num_checked = num_used;
796 
797     while (n > 0) {
798         ret = is_allocated_sectors(buf, n, pnum);
799 
800         buf += BDRV_SECTOR_SIZE * *pnum;
801         n -= *pnum;
802         num_checked += *pnum;
803         if (ret) {
804             num_used = num_checked;
805         } else if (*pnum >= min) {
806             break;
807         }
808     }
809 
810     *pnum = num_used;
811     return 1;
812 }
813 
814 /*
815  * Compares two buffers sector by sector. Returns 0 if the first sector of both
816  * buffers matches, non-zero otherwise.
817  *
818  * pnum is set to the number of sectors (including and immediately following
819  * the first one) that are known to have the same comparison result
820  */
821 static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n,
822     int *pnum)
823 {
824     int res, i;
825 
826     if (n <= 0) {
827         *pnum = 0;
828         return 0;
829     }
830 
831     res = !!memcmp(buf1, buf2, 512);
832     for(i = 1; i < n; i++) {
833         buf1 += 512;
834         buf2 += 512;
835 
836         if (!!memcmp(buf1, buf2, 512) != res) {
837             break;
838         }
839     }
840 
841     *pnum = i;
842     return res;
843 }
844 
845 #define IO_BUF_SIZE (2 * 1024 * 1024)
846 
847 static int64_t sectors_to_bytes(int64_t sectors)
848 {
849     return sectors << BDRV_SECTOR_BITS;
850 }
851 
852 static int64_t sectors_to_process(int64_t total, int64_t from)
853 {
854     return MIN(total - from, IO_BUF_SIZE >> BDRV_SECTOR_BITS);
855 }
856 
857 /*
858  * Check if passed sectors are empty (not allocated or contain only 0 bytes)
859  *
860  * Returns 0 in case sectors are filled with 0, 1 if sectors contain non-zero
861  * data and negative value on error.
862  *
863  * @param bs:  Driver used for accessing file
864  * @param sect_num: Number of first sector to check
865  * @param sect_count: Number of sectors to check
866  * @param filename: Name of disk file we are checking (logging purpose)
867  * @param buffer: Allocated buffer for storing read data
868  * @param quiet: Flag for quiet mode
869  */
870 static int check_empty_sectors(BlockDriverState *bs, int64_t sect_num,
871                                int sect_count, const char *filename,
872                                uint8_t *buffer, bool quiet)
873 {
874     int pnum, ret = 0;
875     ret = bdrv_read(bs, sect_num, buffer, sect_count);
876     if (ret < 0) {
877         error_report("Error while reading offset %" PRId64 " of %s: %s",
878                      sectors_to_bytes(sect_num), filename, strerror(-ret));
879         return ret;
880     }
881     ret = is_allocated_sectors(buffer, sect_count, &pnum);
882     if (ret || pnum != sect_count) {
883         qprintf(quiet, "Content mismatch at offset %" PRId64 "!\n",
884                 sectors_to_bytes(ret ? sect_num : sect_num + pnum));
885         return 1;
886     }
887 
888     return 0;
889 }
890 
891 /*
892  * Compares two images. Exit codes:
893  *
894  * 0 - Images are identical
895  * 1 - Images differ
896  * >1 - Error occurred
897  */
898 static int img_compare(int argc, char **argv)
899 {
900     const char *fmt1 = NULL, *fmt2 = NULL, *filename1, *filename2;
901     BlockDriverState *bs1, *bs2;
902     int64_t total_sectors1, total_sectors2;
903     uint8_t *buf1 = NULL, *buf2 = NULL;
904     int pnum1, pnum2;
905     int allocated1, allocated2;
906     int ret = 0; /* return value - 0 Ident, 1 Different, >1 Error */
907     bool progress = false, quiet = false, strict = false;
908     int64_t total_sectors;
909     int64_t sector_num = 0;
910     int64_t nb_sectors;
911     int c, pnum;
912     uint64_t bs_sectors;
913     uint64_t progress_base;
914 
915     for (;;) {
916         c = getopt(argc, argv, "hpf:F:sq");
917         if (c == -1) {
918             break;
919         }
920         switch (c) {
921         case '?':
922         case 'h':
923             help();
924             break;
925         case 'f':
926             fmt1 = optarg;
927             break;
928         case 'F':
929             fmt2 = optarg;
930             break;
931         case 'p':
932             progress = true;
933             break;
934         case 'q':
935             quiet = true;
936             break;
937         case 's':
938             strict = true;
939             break;
940         }
941     }
942 
943     /* Progress is not shown in Quiet mode */
944     if (quiet) {
945         progress = false;
946     }
947 
948 
949     if (optind != argc - 2) {
950         help();
951     }
952     filename1 = argv[optind++];
953     filename2 = argv[optind++];
954 
955     /* Initialize before goto out */
956     qemu_progress_init(progress, 2.0);
957 
958     bs1 = bdrv_new_open(filename1, fmt1, BDRV_O_FLAGS, true, quiet);
959     if (!bs1) {
960         error_report("Can't open file %s", filename1);
961         ret = 2;
962         goto out3;
963     }
964 
965     bs2 = bdrv_new_open(filename2, fmt2, BDRV_O_FLAGS, true, quiet);
966     if (!bs2) {
967         error_report("Can't open file %s", filename2);
968         ret = 2;
969         goto out2;
970     }
971 
972     buf1 = qemu_blockalign(bs1, IO_BUF_SIZE);
973     buf2 = qemu_blockalign(bs2, IO_BUF_SIZE);
974     bdrv_get_geometry(bs1, &bs_sectors);
975     total_sectors1 = bs_sectors;
976     bdrv_get_geometry(bs2, &bs_sectors);
977     total_sectors2 = bs_sectors;
978     total_sectors = MIN(total_sectors1, total_sectors2);
979     progress_base = MAX(total_sectors1, total_sectors2);
980 
981     qemu_progress_print(0, 100);
982 
983     if (strict && total_sectors1 != total_sectors2) {
984         ret = 1;
985         qprintf(quiet, "Strict mode: Image size mismatch!\n");
986         goto out;
987     }
988 
989     for (;;) {
990         nb_sectors = sectors_to_process(total_sectors, sector_num);
991         if (nb_sectors <= 0) {
992             break;
993         }
994         allocated1 = bdrv_is_allocated_above(bs1, NULL, sector_num, nb_sectors,
995                                              &pnum1);
996         if (allocated1 < 0) {
997             ret = 3;
998             error_report("Sector allocation test failed for %s", filename1);
999             goto out;
1000         }
1001 
1002         allocated2 = bdrv_is_allocated_above(bs2, NULL, sector_num, nb_sectors,
1003                                              &pnum2);
1004         if (allocated2 < 0) {
1005             ret = 3;
1006             error_report("Sector allocation test failed for %s", filename2);
1007             goto out;
1008         }
1009         nb_sectors = MIN(pnum1, pnum2);
1010 
1011         if (allocated1 == allocated2) {
1012             if (allocated1) {
1013                 ret = bdrv_read(bs1, sector_num, buf1, nb_sectors);
1014                 if (ret < 0) {
1015                     error_report("Error while reading offset %" PRId64 " of %s:"
1016                                  " %s", sectors_to_bytes(sector_num), filename1,
1017                                  strerror(-ret));
1018                     ret = 4;
1019                     goto out;
1020                 }
1021                 ret = bdrv_read(bs2, sector_num, buf2, nb_sectors);
1022                 if (ret < 0) {
1023                     error_report("Error while reading offset %" PRId64
1024                                  " of %s: %s", sectors_to_bytes(sector_num),
1025                                  filename2, strerror(-ret));
1026                     ret = 4;
1027                     goto out;
1028                 }
1029                 ret = compare_sectors(buf1, buf2, nb_sectors, &pnum);
1030                 if (ret || pnum != nb_sectors) {
1031                     qprintf(quiet, "Content mismatch at offset %" PRId64 "!\n",
1032                             sectors_to_bytes(
1033                                 ret ? sector_num : sector_num + pnum));
1034                     ret = 1;
1035                     goto out;
1036                 }
1037             }
1038         } else {
1039             if (strict) {
1040                 ret = 1;
1041                 qprintf(quiet, "Strict mode: Offset %" PRId64
1042                         " allocation mismatch!\n",
1043                         sectors_to_bytes(sector_num));
1044                 goto out;
1045             }
1046 
1047             if (allocated1) {
1048                 ret = check_empty_sectors(bs1, sector_num, nb_sectors,
1049                                           filename1, buf1, quiet);
1050             } else {
1051                 ret = check_empty_sectors(bs2, sector_num, nb_sectors,
1052                                           filename2, buf1, quiet);
1053             }
1054             if (ret) {
1055                 if (ret < 0) {
1056                     error_report("Error while reading offset %" PRId64 ": %s",
1057                                  sectors_to_bytes(sector_num), strerror(-ret));
1058                     ret = 4;
1059                 }
1060                 goto out;
1061             }
1062         }
1063         sector_num += nb_sectors;
1064         qemu_progress_print(((float) nb_sectors / progress_base)*100, 100);
1065     }
1066 
1067     if (total_sectors1 != total_sectors2) {
1068         BlockDriverState *bs_over;
1069         int64_t total_sectors_over;
1070         const char *filename_over;
1071 
1072         qprintf(quiet, "Warning: Image size mismatch!\n");
1073         if (total_sectors1 > total_sectors2) {
1074             total_sectors_over = total_sectors1;
1075             bs_over = bs1;
1076             filename_over = filename1;
1077         } else {
1078             total_sectors_over = total_sectors2;
1079             bs_over = bs2;
1080             filename_over = filename2;
1081         }
1082 
1083         for (;;) {
1084             nb_sectors = sectors_to_process(total_sectors_over, sector_num);
1085             if (nb_sectors <= 0) {
1086                 break;
1087             }
1088             ret = bdrv_is_allocated_above(bs_over, NULL, sector_num,
1089                                           nb_sectors, &pnum);
1090             if (ret < 0) {
1091                 ret = 3;
1092                 error_report("Sector allocation test failed for %s",
1093                              filename_over);
1094                 goto out;
1095 
1096             }
1097             nb_sectors = pnum;
1098             if (ret) {
1099                 ret = check_empty_sectors(bs_over, sector_num, nb_sectors,
1100                                           filename_over, buf1, quiet);
1101                 if (ret) {
1102                     if (ret < 0) {
1103                         error_report("Error while reading offset %" PRId64
1104                                      " of %s: %s", sectors_to_bytes(sector_num),
1105                                      filename_over, strerror(-ret));
1106                         ret = 4;
1107                     }
1108                     goto out;
1109                 }
1110             }
1111             sector_num += nb_sectors;
1112             qemu_progress_print(((float) nb_sectors / progress_base)*100, 100);
1113         }
1114     }
1115 
1116     qprintf(quiet, "Images are identical.\n");
1117     ret = 0;
1118 
1119 out:
1120     bdrv_unref(bs2);
1121     qemu_vfree(buf1);
1122     qemu_vfree(buf2);
1123 out2:
1124     bdrv_unref(bs1);
1125 out3:
1126     qemu_progress_end();
1127     return ret;
1128 }
1129 
1130 static int img_convert(int argc, char **argv)
1131 {
1132     int c, n, n1, bs_n, bs_i, compress, cluster_sectors, skip_create;
1133     int64_t ret = 0;
1134     int progress = 0, flags;
1135     const char *fmt, *out_fmt, *cache, *out_baseimg, *out_filename;
1136     BlockDriver *drv, *proto_drv;
1137     BlockDriverState **bs = NULL, *out_bs = NULL;
1138     int64_t total_sectors, nb_sectors, sector_num, bs_offset;
1139     uint64_t bs_sectors;
1140     uint8_t * buf = NULL;
1141     size_t bufsectors = IO_BUF_SIZE / BDRV_SECTOR_SIZE;
1142     const uint8_t *buf1;
1143     BlockDriverInfo bdi;
1144     QEMUOptionParameter *param = NULL, *create_options = NULL;
1145     QEMUOptionParameter *out_baseimg_param;
1146     char *options = NULL;
1147     const char *snapshot_name = NULL;
1148     int min_sparse = 8; /* Need at least 4k of zeros for sparse detection */
1149     bool quiet = false;
1150     Error *local_err = NULL;
1151     QemuOpts *sn_opts = NULL;
1152 
1153     fmt = NULL;
1154     out_fmt = "raw";
1155     cache = "unsafe";
1156     out_baseimg = NULL;
1157     compress = 0;
1158     skip_create = 0;
1159     for(;;) {
1160         c = getopt(argc, argv, "f:O:B:s:hce6o:pS:t:qnl:");
1161         if (c == -1) {
1162             break;
1163         }
1164         switch(c) {
1165         case '?':
1166         case 'h':
1167             help();
1168             break;
1169         case 'f':
1170             fmt = optarg;
1171             break;
1172         case 'O':
1173             out_fmt = optarg;
1174             break;
1175         case 'B':
1176             out_baseimg = optarg;
1177             break;
1178         case 'c':
1179             compress = 1;
1180             break;
1181         case 'e':
1182             error_report("option -e is deprecated, please use \'-o "
1183                   "encryption\' instead!");
1184             return 1;
1185         case '6':
1186             error_report("option -6 is deprecated, please use \'-o "
1187                   "compat6\' instead!");
1188             return 1;
1189         case 'o':
1190             options = optarg;
1191             break;
1192         case 's':
1193             snapshot_name = optarg;
1194             break;
1195         case 'l':
1196             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
1197                 sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0);
1198                 if (!sn_opts) {
1199                     error_report("Failed in parsing snapshot param '%s'",
1200                                  optarg);
1201                     return 1;
1202                 }
1203             } else {
1204                 snapshot_name = optarg;
1205             }
1206             break;
1207         case 'S':
1208         {
1209             int64_t sval;
1210             char *end;
1211             sval = strtosz_suffix(optarg, &end, STRTOSZ_DEFSUFFIX_B);
1212             if (sval < 0 || *end) {
1213                 error_report("Invalid minimum zero buffer size for sparse output specified");
1214                 return 1;
1215             }
1216 
1217             min_sparse = sval / BDRV_SECTOR_SIZE;
1218             break;
1219         }
1220         case 'p':
1221             progress = 1;
1222             break;
1223         case 't':
1224             cache = optarg;
1225             break;
1226         case 'q':
1227             quiet = true;
1228             break;
1229         case 'n':
1230             skip_create = 1;
1231             break;
1232         }
1233     }
1234 
1235     if (quiet) {
1236         progress = 0;
1237     }
1238 
1239     bs_n = argc - optind - 1;
1240     if (bs_n < 1) {
1241         help();
1242     }
1243 
1244     out_filename = argv[argc - 1];
1245 
1246     /* Initialize before goto out */
1247     qemu_progress_init(progress, 1.0);
1248 
1249     if (options && is_help_option(options)) {
1250         ret = print_block_option_help(out_filename, out_fmt);
1251         goto out;
1252     }
1253 
1254     if (bs_n > 1 && out_baseimg) {
1255         error_report("-B makes no sense when concatenating multiple input "
1256                      "images");
1257         ret = -1;
1258         goto out;
1259     }
1260 
1261     qemu_progress_print(0, 100);
1262 
1263     bs = g_malloc0(bs_n * sizeof(BlockDriverState *));
1264 
1265     total_sectors = 0;
1266     for (bs_i = 0; bs_i < bs_n; bs_i++) {
1267         bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt, BDRV_O_FLAGS, true,
1268                                  quiet);
1269         if (!bs[bs_i]) {
1270             error_report("Could not open '%s'", argv[optind + bs_i]);
1271             ret = -1;
1272             goto out;
1273         }
1274         bdrv_get_geometry(bs[bs_i], &bs_sectors);
1275         total_sectors += bs_sectors;
1276     }
1277 
1278     if (sn_opts) {
1279         ret = bdrv_snapshot_load_tmp(bs[0],
1280                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
1281                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
1282                                      &local_err);
1283     } else if (snapshot_name != NULL) {
1284         if (bs_n > 1) {
1285             error_report("No support for concatenating multiple snapshot");
1286             ret = -1;
1287             goto out;
1288         }
1289 
1290         bdrv_snapshot_load_tmp_by_id_or_name(bs[0], snapshot_name, &local_err);
1291     }
1292     if (error_is_set(&local_err)) {
1293         error_report("Failed to load snapshot: %s",
1294                      error_get_pretty(local_err));
1295         error_free(local_err);
1296         ret = -1;
1297         goto out;
1298     }
1299 
1300     /* Find driver and parse its options */
1301     drv = bdrv_find_format(out_fmt);
1302     if (!drv) {
1303         error_report("Unknown file format '%s'", out_fmt);
1304         ret = -1;
1305         goto out;
1306     }
1307 
1308     proto_drv = bdrv_find_protocol(out_filename, true);
1309     if (!proto_drv) {
1310         error_report("Unknown protocol '%s'", out_filename);
1311         ret = -1;
1312         goto out;
1313     }
1314 
1315     create_options = append_option_parameters(create_options,
1316                                               drv->create_options);
1317     create_options = append_option_parameters(create_options,
1318                                               proto_drv->create_options);
1319 
1320     if (options) {
1321         param = parse_option_parameters(options, create_options, param);
1322         if (param == NULL) {
1323             error_report("Invalid options for file format '%s'.", out_fmt);
1324             ret = -1;
1325             goto out;
1326         }
1327     } else {
1328         param = parse_option_parameters("", create_options, param);
1329     }
1330 
1331     set_option_parameter_int(param, BLOCK_OPT_SIZE, total_sectors * 512);
1332     ret = add_old_style_options(out_fmt, param, out_baseimg, NULL);
1333     if (ret < 0) {
1334         goto out;
1335     }
1336 
1337     /* Get backing file name if -o backing_file was used */
1338     out_baseimg_param = get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
1339     if (out_baseimg_param) {
1340         out_baseimg = out_baseimg_param->value.s;
1341     }
1342 
1343     /* Check if compression is supported */
1344     if (compress) {
1345         QEMUOptionParameter *encryption =
1346             get_option_parameter(param, BLOCK_OPT_ENCRYPT);
1347         QEMUOptionParameter *preallocation =
1348             get_option_parameter(param, BLOCK_OPT_PREALLOC);
1349 
1350         if (!drv->bdrv_write_compressed) {
1351             error_report("Compression not supported for this file format");
1352             ret = -1;
1353             goto out;
1354         }
1355 
1356         if (encryption && encryption->value.n) {
1357             error_report("Compression and encryption not supported at "
1358                          "the same time");
1359             ret = -1;
1360             goto out;
1361         }
1362 
1363         if (preallocation && preallocation->value.s
1364             && strcmp(preallocation->value.s, "off"))
1365         {
1366             error_report("Compression and preallocation not supported at "
1367                          "the same time");
1368             ret = -1;
1369             goto out;
1370         }
1371     }
1372 
1373     if (!skip_create) {
1374         /* Create the new image */
1375         ret = bdrv_create(drv, out_filename, param, &local_err);
1376         if (ret < 0) {
1377             error_report("%s: error while converting %s: %s",
1378                          out_filename, out_fmt, error_get_pretty(local_err));
1379             error_free(local_err);
1380             goto out;
1381         }
1382     }
1383 
1384     flags = min_sparse ? (BDRV_O_RDWR | BDRV_O_UNMAP) : BDRV_O_RDWR;
1385     ret = bdrv_parse_cache_flags(cache, &flags);
1386     if (ret < 0) {
1387         error_report("Invalid cache option: %s", cache);
1388         return -1;
1389     }
1390 
1391     out_bs = bdrv_new_open(out_filename, out_fmt, flags, true, quiet);
1392     if (!out_bs) {
1393         ret = -1;
1394         goto out;
1395     }
1396 
1397     bs_i = 0;
1398     bs_offset = 0;
1399     bdrv_get_geometry(bs[0], &bs_sectors);
1400 
1401     /* increase bufsectors from the default 4096 (2M) if opt_transfer_length
1402      * or discard_alignment of the out_bs is greater. Limit to 32768 (16MB)
1403      * as maximum. */
1404     bufsectors = MIN(32768,
1405                      MAX(bufsectors, MAX(out_bs->bl.opt_transfer_length,
1406                                          out_bs->bl.discard_alignment))
1407                     );
1408 
1409     buf = qemu_blockalign(out_bs, bufsectors * BDRV_SECTOR_SIZE);
1410 
1411     if (skip_create) {
1412         int64_t output_length = bdrv_getlength(out_bs);
1413         if (output_length < 0) {
1414             error_report("unable to get output image length: %s\n",
1415                          strerror(-output_length));
1416             ret = -1;
1417             goto out;
1418         } else if (output_length < total_sectors << BDRV_SECTOR_BITS) {
1419             error_report("output file is smaller than input file");
1420             ret = -1;
1421             goto out;
1422         }
1423     }
1424 
1425     cluster_sectors = 0;
1426     ret = bdrv_get_info(out_bs, &bdi);
1427     if (ret < 0) {
1428         if (compress) {
1429             error_report("could not get block driver info");
1430             goto out;
1431         }
1432     } else {
1433         cluster_sectors = bdi.cluster_size / BDRV_SECTOR_SIZE;
1434     }
1435 
1436     if (compress) {
1437         if (cluster_sectors <= 0 || cluster_sectors > bufsectors) {
1438             error_report("invalid cluster size");
1439             ret = -1;
1440             goto out;
1441         }
1442         sector_num = 0;
1443 
1444         nb_sectors = total_sectors;
1445 
1446         for(;;) {
1447             int64_t bs_num;
1448             int remainder;
1449             uint8_t *buf2;
1450 
1451             nb_sectors = total_sectors - sector_num;
1452             if (nb_sectors <= 0)
1453                 break;
1454             if (nb_sectors >= cluster_sectors)
1455                 n = cluster_sectors;
1456             else
1457                 n = nb_sectors;
1458 
1459             bs_num = sector_num - bs_offset;
1460             assert (bs_num >= 0);
1461             remainder = n;
1462             buf2 = buf;
1463             while (remainder > 0) {
1464                 int nlow;
1465                 while (bs_num == bs_sectors) {
1466                     bs_i++;
1467                     assert (bs_i < bs_n);
1468                     bs_offset += bs_sectors;
1469                     bdrv_get_geometry(bs[bs_i], &bs_sectors);
1470                     bs_num = 0;
1471                     /* printf("changing part: sector_num=%" PRId64 ", "
1472                        "bs_i=%d, bs_offset=%" PRId64 ", bs_sectors=%" PRId64
1473                        "\n", sector_num, bs_i, bs_offset, bs_sectors); */
1474                 }
1475                 assert (bs_num < bs_sectors);
1476 
1477                 nlow = (remainder > bs_sectors - bs_num) ? bs_sectors - bs_num : remainder;
1478 
1479                 ret = bdrv_read(bs[bs_i], bs_num, buf2, nlow);
1480                 if (ret < 0) {
1481                     error_report("error while reading sector %" PRId64 ": %s",
1482                                  bs_num, strerror(-ret));
1483                     goto out;
1484                 }
1485 
1486                 buf2 += nlow * 512;
1487                 bs_num += nlow;
1488 
1489                 remainder -= nlow;
1490             }
1491             assert (remainder == 0);
1492 
1493             if (!buffer_is_zero(buf, n * BDRV_SECTOR_SIZE)) {
1494                 ret = bdrv_write_compressed(out_bs, sector_num, buf, n);
1495                 if (ret != 0) {
1496                     error_report("error while compressing sector %" PRId64
1497                                  ": %s", sector_num, strerror(-ret));
1498                     goto out;
1499                 }
1500             }
1501             sector_num += n;
1502             qemu_progress_print(100.0 * sector_num / total_sectors, 0);
1503         }
1504         /* signal EOF to align */
1505         bdrv_write_compressed(out_bs, 0, NULL, 0);
1506     } else {
1507         int64_t sectors_to_read, sectors_read, sector_num_next_status;
1508         bool count_allocated_sectors;
1509         int has_zero_init = min_sparse ? bdrv_has_zero_init(out_bs) : 0;
1510 
1511         if (!has_zero_init && bdrv_can_write_zeroes_with_unmap(out_bs)) {
1512             ret = bdrv_make_zero(out_bs, BDRV_REQ_MAY_UNMAP);
1513             if (ret < 0) {
1514                 goto out;
1515             }
1516             has_zero_init = 1;
1517         }
1518 
1519         sectors_to_read = total_sectors;
1520         count_allocated_sectors = progress && (out_baseimg || has_zero_init);
1521 restart:
1522         sector_num = 0; // total number of sectors converted so far
1523         sectors_read = 0;
1524         sector_num_next_status = 0;
1525 
1526         for(;;) {
1527             nb_sectors = total_sectors - sector_num;
1528             if (nb_sectors <= 0) {
1529                 if (count_allocated_sectors) {
1530                     sectors_to_read = sectors_read;
1531                     count_allocated_sectors = false;
1532                     goto restart;
1533                 }
1534                 ret = 0;
1535                 break;
1536             }
1537 
1538             while (sector_num - bs_offset >= bs_sectors) {
1539                 bs_i ++;
1540                 assert (bs_i < bs_n);
1541                 bs_offset += bs_sectors;
1542                 bdrv_get_geometry(bs[bs_i], &bs_sectors);
1543                 /* printf("changing part: sector_num=%" PRId64 ", bs_i=%d, "
1544                   "bs_offset=%" PRId64 ", bs_sectors=%" PRId64 "\n",
1545                    sector_num, bs_i, bs_offset, bs_sectors); */
1546             }
1547 
1548             if ((out_baseimg || has_zero_init) &&
1549                 sector_num >= sector_num_next_status) {
1550                 n = nb_sectors > INT_MAX ? INT_MAX : nb_sectors;
1551                 ret = bdrv_get_block_status(bs[bs_i], sector_num - bs_offset,
1552                                             n, &n1);
1553                 if (ret < 0) {
1554                     error_report("error while reading block status of sector %"
1555                                  PRId64 ": %s", sector_num - bs_offset,
1556                                  strerror(-ret));
1557                     goto out;
1558                 }
1559                 /* If the output image is zero initialized, we are not working
1560                  * on a shared base and the input is zero we can skip the next
1561                  * n1 sectors */
1562                 if (has_zero_init && !out_baseimg && (ret & BDRV_BLOCK_ZERO)) {
1563                     sector_num += n1;
1564                     continue;
1565                 }
1566                 /* If the output image is being created as a copy on write
1567                  * image, assume that sectors which are unallocated in the
1568                  * input image are present in both the output's and input's
1569                  * base images (no need to copy them). */
1570                 if (out_baseimg) {
1571                     if (!(ret & BDRV_BLOCK_DATA)) {
1572                         sector_num += n1;
1573                         continue;
1574                     }
1575                     /* The next 'n1' sectors are allocated in the input image.
1576                      * Copy only those as they may be followed by unallocated
1577                      * sectors. */
1578                     nb_sectors = n1;
1579                 }
1580                 /* avoid redundant callouts to get_block_status */
1581                 sector_num_next_status = sector_num + n1;
1582             }
1583 
1584             n = MIN(nb_sectors, bufsectors);
1585 
1586             /* round down request length to an aligned sector, but
1587              * do not bother doing this on short requests. They happen
1588              * when we found an all-zero area, and the next sector to
1589              * write will not be sector_num + n. */
1590             if (cluster_sectors > 0 && n >= cluster_sectors) {
1591                 int64_t next_aligned_sector = (sector_num + n);
1592                 next_aligned_sector -= next_aligned_sector % cluster_sectors;
1593                 if (sector_num + n > next_aligned_sector) {
1594                     n = next_aligned_sector - sector_num;
1595                 }
1596             }
1597 
1598             n = MIN(n, bs_sectors - (sector_num - bs_offset));
1599 
1600             sectors_read += n;
1601             if (count_allocated_sectors) {
1602                 sector_num += n;
1603                 continue;
1604             }
1605 
1606             n1 = n;
1607             ret = bdrv_read(bs[bs_i], sector_num - bs_offset, buf, n);
1608             if (ret < 0) {
1609                 error_report("error while reading sector %" PRId64 ": %s",
1610                              sector_num - bs_offset, strerror(-ret));
1611                 goto out;
1612             }
1613             /* NOTE: at the same time we convert, we do not write zero
1614                sectors to have a chance to compress the image. Ideally, we
1615                should add a specific call to have the info to go faster */
1616             buf1 = buf;
1617             while (n > 0) {
1618                 if (!has_zero_init ||
1619                     is_allocated_sectors_min(buf1, n, &n1, min_sparse)) {
1620                     ret = bdrv_write(out_bs, sector_num, buf1, n1);
1621                     if (ret < 0) {
1622                         error_report("error while writing sector %" PRId64
1623                                      ": %s", sector_num, strerror(-ret));
1624                         goto out;
1625                     }
1626                 }
1627                 sector_num += n1;
1628                 n -= n1;
1629                 buf1 += n1 * 512;
1630             }
1631             qemu_progress_print(100.0 * sectors_read / sectors_to_read, 0);
1632         }
1633     }
1634 out:
1635     if (!ret) {
1636         qemu_progress_print(100, 0);
1637     }
1638     qemu_progress_end();
1639     free_option_parameters(create_options);
1640     free_option_parameters(param);
1641     qemu_vfree(buf);
1642     if (sn_opts) {
1643         qemu_opts_del(sn_opts);
1644     }
1645     if (out_bs) {
1646         bdrv_unref(out_bs);
1647     }
1648     if (bs) {
1649         for (bs_i = 0; bs_i < bs_n; bs_i++) {
1650             if (bs[bs_i]) {
1651                 bdrv_unref(bs[bs_i]);
1652             }
1653         }
1654         g_free(bs);
1655     }
1656     if (ret) {
1657         return 1;
1658     }
1659     return 0;
1660 }
1661 
1662 
1663 static void dump_snapshots(BlockDriverState *bs)
1664 {
1665     QEMUSnapshotInfo *sn_tab, *sn;
1666     int nb_sns, i;
1667 
1668     nb_sns = bdrv_snapshot_list(bs, &sn_tab);
1669     if (nb_sns <= 0)
1670         return;
1671     printf("Snapshot list:\n");
1672     bdrv_snapshot_dump(fprintf, stdout, NULL);
1673     printf("\n");
1674     for(i = 0; i < nb_sns; i++) {
1675         sn = &sn_tab[i];
1676         bdrv_snapshot_dump(fprintf, stdout, sn);
1677         printf("\n");
1678     }
1679     g_free(sn_tab);
1680 }
1681 
1682 static void dump_json_image_info_list(ImageInfoList *list)
1683 {
1684     Error *errp = NULL;
1685     QString *str;
1686     QmpOutputVisitor *ov = qmp_output_visitor_new();
1687     QObject *obj;
1688     visit_type_ImageInfoList(qmp_output_get_visitor(ov),
1689                              &list, NULL, &errp);
1690     obj = qmp_output_get_qobject(ov);
1691     str = qobject_to_json_pretty(obj);
1692     assert(str != NULL);
1693     printf("%s\n", qstring_get_str(str));
1694     qobject_decref(obj);
1695     qmp_output_visitor_cleanup(ov);
1696     QDECREF(str);
1697 }
1698 
1699 static void dump_json_image_info(ImageInfo *info)
1700 {
1701     Error *errp = NULL;
1702     QString *str;
1703     QmpOutputVisitor *ov = qmp_output_visitor_new();
1704     QObject *obj;
1705     visit_type_ImageInfo(qmp_output_get_visitor(ov),
1706                          &info, NULL, &errp);
1707     obj = qmp_output_get_qobject(ov);
1708     str = qobject_to_json_pretty(obj);
1709     assert(str != NULL);
1710     printf("%s\n", qstring_get_str(str));
1711     qobject_decref(obj);
1712     qmp_output_visitor_cleanup(ov);
1713     QDECREF(str);
1714 }
1715 
1716 static void dump_human_image_info_list(ImageInfoList *list)
1717 {
1718     ImageInfoList *elem;
1719     bool delim = false;
1720 
1721     for (elem = list; elem; elem = elem->next) {
1722         if (delim) {
1723             printf("\n");
1724         }
1725         delim = true;
1726 
1727         bdrv_image_info_dump(fprintf, stdout, elem->value);
1728     }
1729 }
1730 
1731 static gboolean str_equal_func(gconstpointer a, gconstpointer b)
1732 {
1733     return strcmp(a, b) == 0;
1734 }
1735 
1736 /**
1737  * Open an image file chain and return an ImageInfoList
1738  *
1739  * @filename: topmost image filename
1740  * @fmt: topmost image format (may be NULL to autodetect)
1741  * @chain: true  - enumerate entire backing file chain
1742  *         false - only topmost image file
1743  *
1744  * Returns a list of ImageInfo objects or NULL if there was an error opening an
1745  * image file.  If there was an error a message will have been printed to
1746  * stderr.
1747  */
1748 static ImageInfoList *collect_image_info_list(const char *filename,
1749                                               const char *fmt,
1750                                               bool chain)
1751 {
1752     ImageInfoList *head = NULL;
1753     ImageInfoList **last = &head;
1754     GHashTable *filenames;
1755     Error *err = NULL;
1756 
1757     filenames = g_hash_table_new_full(g_str_hash, str_equal_func, NULL, NULL);
1758 
1759     while (filename) {
1760         BlockDriverState *bs;
1761         ImageInfo *info;
1762         ImageInfoList *elem;
1763 
1764         if (g_hash_table_lookup_extended(filenames, filename, NULL, NULL)) {
1765             error_report("Backing file '%s' creates an infinite loop.",
1766                          filename);
1767             goto err;
1768         }
1769         g_hash_table_insert(filenames, (gpointer)filename, NULL);
1770 
1771         bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING,
1772                            false, false);
1773         if (!bs) {
1774             goto err;
1775         }
1776 
1777         bdrv_query_image_info(bs, &info, &err);
1778         if (error_is_set(&err)) {
1779             error_report("%s", error_get_pretty(err));
1780             error_free(err);
1781             goto err;
1782         }
1783 
1784         elem = g_new0(ImageInfoList, 1);
1785         elem->value = info;
1786         *last = elem;
1787         last = &elem->next;
1788 
1789         bdrv_unref(bs);
1790 
1791         filename = fmt = NULL;
1792         if (chain) {
1793             if (info->has_full_backing_filename) {
1794                 filename = info->full_backing_filename;
1795             } else if (info->has_backing_filename) {
1796                 filename = info->backing_filename;
1797             }
1798             if (info->has_backing_filename_format) {
1799                 fmt = info->backing_filename_format;
1800             }
1801         }
1802     }
1803     g_hash_table_destroy(filenames);
1804     return head;
1805 
1806 err:
1807     qapi_free_ImageInfoList(head);
1808     g_hash_table_destroy(filenames);
1809     return NULL;
1810 }
1811 
1812 static int img_info(int argc, char **argv)
1813 {
1814     int c;
1815     OutputFormat output_format = OFORMAT_HUMAN;
1816     bool chain = false;
1817     const char *filename, *fmt, *output;
1818     ImageInfoList *list;
1819 
1820     fmt = NULL;
1821     output = NULL;
1822     for(;;) {
1823         int option_index = 0;
1824         static const struct option long_options[] = {
1825             {"help", no_argument, 0, 'h'},
1826             {"format", required_argument, 0, 'f'},
1827             {"output", required_argument, 0, OPTION_OUTPUT},
1828             {"backing-chain", no_argument, 0, OPTION_BACKING_CHAIN},
1829             {0, 0, 0, 0}
1830         };
1831         c = getopt_long(argc, argv, "f:h",
1832                         long_options, &option_index);
1833         if (c == -1) {
1834             break;
1835         }
1836         switch(c) {
1837         case '?':
1838         case 'h':
1839             help();
1840             break;
1841         case 'f':
1842             fmt = optarg;
1843             break;
1844         case OPTION_OUTPUT:
1845             output = optarg;
1846             break;
1847         case OPTION_BACKING_CHAIN:
1848             chain = true;
1849             break;
1850         }
1851     }
1852     if (optind != argc - 1) {
1853         help();
1854     }
1855     filename = argv[optind++];
1856 
1857     if (output && !strcmp(output, "json")) {
1858         output_format = OFORMAT_JSON;
1859     } else if (output && !strcmp(output, "human")) {
1860         output_format = OFORMAT_HUMAN;
1861     } else if (output) {
1862         error_report("--output must be used with human or json as argument.");
1863         return 1;
1864     }
1865 
1866     list = collect_image_info_list(filename, fmt, chain);
1867     if (!list) {
1868         return 1;
1869     }
1870 
1871     switch (output_format) {
1872     case OFORMAT_HUMAN:
1873         dump_human_image_info_list(list);
1874         break;
1875     case OFORMAT_JSON:
1876         if (chain) {
1877             dump_json_image_info_list(list);
1878         } else {
1879             dump_json_image_info(list->value);
1880         }
1881         break;
1882     }
1883 
1884     qapi_free_ImageInfoList(list);
1885     return 0;
1886 }
1887 
1888 
1889 typedef struct MapEntry {
1890     int flags;
1891     int depth;
1892     int64_t start;
1893     int64_t length;
1894     int64_t offset;
1895     BlockDriverState *bs;
1896 } MapEntry;
1897 
1898 static void dump_map_entry(OutputFormat output_format, MapEntry *e,
1899                            MapEntry *next)
1900 {
1901     switch (output_format) {
1902     case OFORMAT_HUMAN:
1903         if ((e->flags & BDRV_BLOCK_DATA) &&
1904             !(e->flags & BDRV_BLOCK_OFFSET_VALID)) {
1905             error_report("File contains external, encrypted or compressed clusters.");
1906             exit(1);
1907         }
1908         if ((e->flags & (BDRV_BLOCK_DATA|BDRV_BLOCK_ZERO)) == BDRV_BLOCK_DATA) {
1909             printf("%#-16"PRIx64"%#-16"PRIx64"%#-16"PRIx64"%s\n",
1910                    e->start, e->length, e->offset, e->bs->filename);
1911         }
1912         /* This format ignores the distinction between 0, ZERO and ZERO|DATA.
1913          * Modify the flags here to allow more coalescing.
1914          */
1915         if (next &&
1916             (next->flags & (BDRV_BLOCK_DATA|BDRV_BLOCK_ZERO)) != BDRV_BLOCK_DATA) {
1917             next->flags &= ~BDRV_BLOCK_DATA;
1918             next->flags |= BDRV_BLOCK_ZERO;
1919         }
1920         break;
1921     case OFORMAT_JSON:
1922         printf("%s{ \"start\": %"PRId64", \"length\": %"PRId64", \"depth\": %d,"
1923                " \"zero\": %s, \"data\": %s",
1924                (e->start == 0 ? "[" : ",\n"),
1925                e->start, e->length, e->depth,
1926                (e->flags & BDRV_BLOCK_ZERO) ? "true" : "false",
1927                (e->flags & BDRV_BLOCK_DATA) ? "true" : "false");
1928         if (e->flags & BDRV_BLOCK_OFFSET_VALID) {
1929             printf(", \"offset\": %"PRId64"", e->offset);
1930         }
1931         putchar('}');
1932 
1933         if (!next) {
1934             printf("]\n");
1935         }
1936         break;
1937     }
1938 }
1939 
1940 static int get_block_status(BlockDriverState *bs, int64_t sector_num,
1941                             int nb_sectors, MapEntry *e)
1942 {
1943     int64_t ret;
1944     int depth;
1945 
1946     /* As an optimization, we could cache the current range of unallocated
1947      * clusters in each file of the chain, and avoid querying the same
1948      * range repeatedly.
1949      */
1950 
1951     depth = 0;
1952     for (;;) {
1953         ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &nb_sectors);
1954         if (ret < 0) {
1955             return ret;
1956         }
1957         assert(nb_sectors);
1958         if (ret & (BDRV_BLOCK_ZERO|BDRV_BLOCK_DATA)) {
1959             break;
1960         }
1961         bs = bs->backing_hd;
1962         if (bs == NULL) {
1963             ret = 0;
1964             break;
1965         }
1966 
1967         depth++;
1968     }
1969 
1970     e->start = sector_num * BDRV_SECTOR_SIZE;
1971     e->length = nb_sectors * BDRV_SECTOR_SIZE;
1972     e->flags = ret & ~BDRV_BLOCK_OFFSET_MASK;
1973     e->offset = ret & BDRV_BLOCK_OFFSET_MASK;
1974     e->depth = depth;
1975     e->bs = bs;
1976     return 0;
1977 }
1978 
1979 static int img_map(int argc, char **argv)
1980 {
1981     int c;
1982     OutputFormat output_format = OFORMAT_HUMAN;
1983     BlockDriverState *bs;
1984     const char *filename, *fmt, *output;
1985     int64_t length;
1986     MapEntry curr = { .length = 0 }, next;
1987     int ret = 0;
1988 
1989     fmt = NULL;
1990     output = NULL;
1991     for (;;) {
1992         int option_index = 0;
1993         static const struct option long_options[] = {
1994             {"help", no_argument, 0, 'h'},
1995             {"format", required_argument, 0, 'f'},
1996             {"output", required_argument, 0, OPTION_OUTPUT},
1997             {0, 0, 0, 0}
1998         };
1999         c = getopt_long(argc, argv, "f:h",
2000                         long_options, &option_index);
2001         if (c == -1) {
2002             break;
2003         }
2004         switch (c) {
2005         case '?':
2006         case 'h':
2007             help();
2008             break;
2009         case 'f':
2010             fmt = optarg;
2011             break;
2012         case OPTION_OUTPUT:
2013             output = optarg;
2014             break;
2015         }
2016     }
2017     if (optind >= argc) {
2018         help();
2019     }
2020     filename = argv[optind++];
2021 
2022     if (output && !strcmp(output, "json")) {
2023         output_format = OFORMAT_JSON;
2024     } else if (output && !strcmp(output, "human")) {
2025         output_format = OFORMAT_HUMAN;
2026     } else if (output) {
2027         error_report("--output must be used with human or json as argument.");
2028         return 1;
2029     }
2030 
2031     bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS, true, false);
2032     if (!bs) {
2033         return 1;
2034     }
2035 
2036     if (output_format == OFORMAT_HUMAN) {
2037         printf("%-16s%-16s%-16s%s\n", "Offset", "Length", "Mapped to", "File");
2038     }
2039 
2040     length = bdrv_getlength(bs);
2041     while (curr.start + curr.length < length) {
2042         int64_t nsectors_left;
2043         int64_t sector_num;
2044         int n;
2045 
2046         sector_num = (curr.start + curr.length) >> BDRV_SECTOR_BITS;
2047 
2048         /* Probe up to 1 GiB at a time.  */
2049         nsectors_left = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE) - sector_num;
2050         n = MIN(1 << (30 - BDRV_SECTOR_BITS), nsectors_left);
2051         ret = get_block_status(bs, sector_num, n, &next);
2052 
2053         if (ret < 0) {
2054             error_report("Could not read file metadata: %s", strerror(-ret));
2055             goto out;
2056         }
2057 
2058         if (curr.length != 0 && curr.flags == next.flags &&
2059             curr.depth == next.depth &&
2060             ((curr.flags & BDRV_BLOCK_OFFSET_VALID) == 0 ||
2061              curr.offset + curr.length == next.offset)) {
2062             curr.length += next.length;
2063             continue;
2064         }
2065 
2066         if (curr.length > 0) {
2067             dump_map_entry(output_format, &curr, &next);
2068         }
2069         curr = next;
2070     }
2071 
2072     dump_map_entry(output_format, &curr, NULL);
2073 
2074 out:
2075     bdrv_unref(bs);
2076     return ret < 0;
2077 }
2078 
2079 #define SNAPSHOT_LIST   1
2080 #define SNAPSHOT_CREATE 2
2081 #define SNAPSHOT_APPLY  3
2082 #define SNAPSHOT_DELETE 4
2083 
2084 static int img_snapshot(int argc, char **argv)
2085 {
2086     BlockDriverState *bs;
2087     QEMUSnapshotInfo sn;
2088     char *filename, *snapshot_name = NULL;
2089     int c, ret = 0, bdrv_oflags;
2090     int action = 0;
2091     qemu_timeval tv;
2092     bool quiet = false;
2093     Error *err = NULL;
2094 
2095     bdrv_oflags = BDRV_O_FLAGS | BDRV_O_RDWR;
2096     /* Parse commandline parameters */
2097     for(;;) {
2098         c = getopt(argc, argv, "la:c:d:hq");
2099         if (c == -1) {
2100             break;
2101         }
2102         switch(c) {
2103         case '?':
2104         case 'h':
2105             help();
2106             return 0;
2107         case 'l':
2108             if (action) {
2109                 help();
2110                 return 0;
2111             }
2112             action = SNAPSHOT_LIST;
2113             bdrv_oflags &= ~BDRV_O_RDWR; /* no need for RW */
2114             break;
2115         case 'a':
2116             if (action) {
2117                 help();
2118                 return 0;
2119             }
2120             action = SNAPSHOT_APPLY;
2121             snapshot_name = optarg;
2122             break;
2123         case 'c':
2124             if (action) {
2125                 help();
2126                 return 0;
2127             }
2128             action = SNAPSHOT_CREATE;
2129             snapshot_name = optarg;
2130             break;
2131         case 'd':
2132             if (action) {
2133                 help();
2134                 return 0;
2135             }
2136             action = SNAPSHOT_DELETE;
2137             snapshot_name = optarg;
2138             break;
2139         case 'q':
2140             quiet = true;
2141             break;
2142         }
2143     }
2144 
2145     if (optind != argc - 1) {
2146         help();
2147     }
2148     filename = argv[optind++];
2149 
2150     /* Open the image */
2151     bs = bdrv_new_open(filename, NULL, bdrv_oflags, true, quiet);
2152     if (!bs) {
2153         return 1;
2154     }
2155 
2156     /* Perform the requested action */
2157     switch(action) {
2158     case SNAPSHOT_LIST:
2159         dump_snapshots(bs);
2160         break;
2161 
2162     case SNAPSHOT_CREATE:
2163         memset(&sn, 0, sizeof(sn));
2164         pstrcpy(sn.name, sizeof(sn.name), snapshot_name);
2165 
2166         qemu_gettimeofday(&tv);
2167         sn.date_sec = tv.tv_sec;
2168         sn.date_nsec = tv.tv_usec * 1000;
2169 
2170         ret = bdrv_snapshot_create(bs, &sn);
2171         if (ret) {
2172             error_report("Could not create snapshot '%s': %d (%s)",
2173                 snapshot_name, ret, strerror(-ret));
2174         }
2175         break;
2176 
2177     case SNAPSHOT_APPLY:
2178         ret = bdrv_snapshot_goto(bs, snapshot_name);
2179         if (ret) {
2180             error_report("Could not apply snapshot '%s': %d (%s)",
2181                 snapshot_name, ret, strerror(-ret));
2182         }
2183         break;
2184 
2185     case SNAPSHOT_DELETE:
2186         bdrv_snapshot_delete_by_id_or_name(bs, snapshot_name, &err);
2187         if (error_is_set(&err)) {
2188             error_report("Could not delete snapshot '%s': (%s)",
2189                          snapshot_name, error_get_pretty(err));
2190             error_free(err);
2191             ret = 1;
2192         }
2193         break;
2194     }
2195 
2196     /* Cleanup */
2197     bdrv_unref(bs);
2198     if (ret) {
2199         return 1;
2200     }
2201     return 0;
2202 }
2203 
2204 static int img_rebase(int argc, char **argv)
2205 {
2206     BlockDriverState *bs, *bs_old_backing = NULL, *bs_new_backing = NULL;
2207     BlockDriver *old_backing_drv, *new_backing_drv;
2208     char *filename;
2209     const char *fmt, *cache, *out_basefmt, *out_baseimg;
2210     int c, flags, ret;
2211     int unsafe = 0;
2212     int progress = 0;
2213     bool quiet = false;
2214     Error *local_err = NULL;
2215 
2216     /* Parse commandline parameters */
2217     fmt = NULL;
2218     cache = BDRV_DEFAULT_CACHE;
2219     out_baseimg = NULL;
2220     out_basefmt = NULL;
2221     for(;;) {
2222         c = getopt(argc, argv, "uhf:F:b:pt:q");
2223         if (c == -1) {
2224             break;
2225         }
2226         switch(c) {
2227         case '?':
2228         case 'h':
2229             help();
2230             return 0;
2231         case 'f':
2232             fmt = optarg;
2233             break;
2234         case 'F':
2235             out_basefmt = optarg;
2236             break;
2237         case 'b':
2238             out_baseimg = optarg;
2239             break;
2240         case 'u':
2241             unsafe = 1;
2242             break;
2243         case 'p':
2244             progress = 1;
2245             break;
2246         case 't':
2247             cache = optarg;
2248             break;
2249         case 'q':
2250             quiet = true;
2251             break;
2252         }
2253     }
2254 
2255     if (quiet) {
2256         progress = 0;
2257     }
2258 
2259     if ((optind != argc - 1) || (!unsafe && !out_baseimg)) {
2260         help();
2261     }
2262     filename = argv[optind++];
2263 
2264     qemu_progress_init(progress, 2.0);
2265     qemu_progress_print(0, 100);
2266 
2267     flags = BDRV_O_RDWR | (unsafe ? BDRV_O_NO_BACKING : 0);
2268     ret = bdrv_parse_cache_flags(cache, &flags);
2269     if (ret < 0) {
2270         error_report("Invalid cache option: %s", cache);
2271         return -1;
2272     }
2273 
2274     /*
2275      * Open the images.
2276      *
2277      * Ignore the old backing file for unsafe rebase in case we want to correct
2278      * the reference to a renamed or moved backing file.
2279      */
2280     bs = bdrv_new_open(filename, fmt, flags, true, quiet);
2281     if (!bs) {
2282         return 1;
2283     }
2284 
2285     /* Find the right drivers for the backing files */
2286     old_backing_drv = NULL;
2287     new_backing_drv = NULL;
2288 
2289     if (!unsafe && bs->backing_format[0] != '\0') {
2290         old_backing_drv = bdrv_find_format(bs->backing_format);
2291         if (old_backing_drv == NULL) {
2292             error_report("Invalid format name: '%s'", bs->backing_format);
2293             ret = -1;
2294             goto out;
2295         }
2296     }
2297 
2298     if (out_basefmt != NULL) {
2299         new_backing_drv = bdrv_find_format(out_basefmt);
2300         if (new_backing_drv == NULL) {
2301             error_report("Invalid format name: '%s'", out_basefmt);
2302             ret = -1;
2303             goto out;
2304         }
2305     }
2306 
2307     /* For safe rebasing we need to compare old and new backing file */
2308     if (unsafe) {
2309         /* Make the compiler happy */
2310         bs_old_backing = NULL;
2311         bs_new_backing = NULL;
2312     } else {
2313         char backing_name[1024];
2314 
2315         bs_old_backing = bdrv_new("old_backing");
2316         bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name));
2317         ret = bdrv_open(bs_old_backing, backing_name, NULL, BDRV_O_FLAGS,
2318                         old_backing_drv, &local_err);
2319         if (ret) {
2320             error_report("Could not open old backing file '%s': %s",
2321                          backing_name, error_get_pretty(local_err));
2322             error_free(local_err);
2323             goto out;
2324         }
2325         if (out_baseimg[0]) {
2326             bs_new_backing = bdrv_new("new_backing");
2327             ret = bdrv_open(bs_new_backing, out_baseimg, NULL, BDRV_O_FLAGS,
2328                         new_backing_drv, &local_err);
2329             if (ret) {
2330                 error_report("Could not open new backing file '%s': %s",
2331                              out_baseimg, error_get_pretty(local_err));
2332                 error_free(local_err);
2333                 goto out;
2334             }
2335         }
2336     }
2337 
2338     /*
2339      * Check each unallocated cluster in the COW file. If it is unallocated,
2340      * accesses go to the backing file. We must therefore compare this cluster
2341      * in the old and new backing file, and if they differ we need to copy it
2342      * from the old backing file into the COW file.
2343      *
2344      * If qemu-img crashes during this step, no harm is done. The content of
2345      * the image is the same as the original one at any time.
2346      */
2347     if (!unsafe) {
2348         uint64_t num_sectors;
2349         uint64_t old_backing_num_sectors;
2350         uint64_t new_backing_num_sectors = 0;
2351         uint64_t sector;
2352         int n;
2353         uint8_t * buf_old;
2354         uint8_t * buf_new;
2355         float local_progress = 0;
2356 
2357         buf_old = qemu_blockalign(bs, IO_BUF_SIZE);
2358         buf_new = qemu_blockalign(bs, IO_BUF_SIZE);
2359 
2360         bdrv_get_geometry(bs, &num_sectors);
2361         bdrv_get_geometry(bs_old_backing, &old_backing_num_sectors);
2362         if (bs_new_backing) {
2363             bdrv_get_geometry(bs_new_backing, &new_backing_num_sectors);
2364         }
2365 
2366         if (num_sectors != 0) {
2367             local_progress = (float)100 /
2368                 (num_sectors / MIN(num_sectors, IO_BUF_SIZE / 512));
2369         }
2370 
2371         for (sector = 0; sector < num_sectors; sector += n) {
2372 
2373             /* How many sectors can we handle with the next read? */
2374             if (sector + (IO_BUF_SIZE / 512) <= num_sectors) {
2375                 n = (IO_BUF_SIZE / 512);
2376             } else {
2377                 n = num_sectors - sector;
2378             }
2379 
2380             /* If the cluster is allocated, we don't need to take action */
2381             ret = bdrv_is_allocated(bs, sector, n, &n);
2382             if (ret < 0) {
2383                 error_report("error while reading image metadata: %s",
2384                              strerror(-ret));
2385                 goto out;
2386             }
2387             if (ret) {
2388                 continue;
2389             }
2390 
2391             /*
2392              * Read old and new backing file and take into consideration that
2393              * backing files may be smaller than the COW image.
2394              */
2395             if (sector >= old_backing_num_sectors) {
2396                 memset(buf_old, 0, n * BDRV_SECTOR_SIZE);
2397             } else {
2398                 if (sector + n > old_backing_num_sectors) {
2399                     n = old_backing_num_sectors - sector;
2400                 }
2401 
2402                 ret = bdrv_read(bs_old_backing, sector, buf_old, n);
2403                 if (ret < 0) {
2404                     error_report("error while reading from old backing file");
2405                     goto out;
2406                 }
2407             }
2408 
2409             if (sector >= new_backing_num_sectors || !bs_new_backing) {
2410                 memset(buf_new, 0, n * BDRV_SECTOR_SIZE);
2411             } else {
2412                 if (sector + n > new_backing_num_sectors) {
2413                     n = new_backing_num_sectors - sector;
2414                 }
2415 
2416                 ret = bdrv_read(bs_new_backing, sector, buf_new, n);
2417                 if (ret < 0) {
2418                     error_report("error while reading from new backing file");
2419                     goto out;
2420                 }
2421             }
2422 
2423             /* If they differ, we need to write to the COW file */
2424             uint64_t written = 0;
2425 
2426             while (written < n) {
2427                 int pnum;
2428 
2429                 if (compare_sectors(buf_old + written * 512,
2430                     buf_new + written * 512, n - written, &pnum))
2431                 {
2432                     ret = bdrv_write(bs, sector + written,
2433                         buf_old + written * 512, pnum);
2434                     if (ret < 0) {
2435                         error_report("Error while writing to COW image: %s",
2436                             strerror(-ret));
2437                         goto out;
2438                     }
2439                 }
2440 
2441                 written += pnum;
2442             }
2443             qemu_progress_print(local_progress, 100);
2444         }
2445 
2446         qemu_vfree(buf_old);
2447         qemu_vfree(buf_new);
2448     }
2449 
2450     /*
2451      * Change the backing file. All clusters that are different from the old
2452      * backing file are overwritten in the COW file now, so the visible content
2453      * doesn't change when we switch the backing file.
2454      */
2455     if (out_baseimg && *out_baseimg) {
2456         ret = bdrv_change_backing_file(bs, out_baseimg, out_basefmt);
2457     } else {
2458         ret = bdrv_change_backing_file(bs, NULL, NULL);
2459     }
2460 
2461     if (ret == -ENOSPC) {
2462         error_report("Could not change the backing file to '%s': No "
2463                      "space left in the file header", out_baseimg);
2464     } else if (ret < 0) {
2465         error_report("Could not change the backing file to '%s': %s",
2466             out_baseimg, strerror(-ret));
2467     }
2468 
2469     qemu_progress_print(100, 0);
2470     /*
2471      * TODO At this point it is possible to check if any clusters that are
2472      * allocated in the COW file are the same in the backing file. If so, they
2473      * could be dropped from the COW file. Don't do this before switching the
2474      * backing file, in case of a crash this would lead to corruption.
2475      */
2476 out:
2477     qemu_progress_end();
2478     /* Cleanup */
2479     if (!unsafe) {
2480         if (bs_old_backing != NULL) {
2481             bdrv_unref(bs_old_backing);
2482         }
2483         if (bs_new_backing != NULL) {
2484             bdrv_unref(bs_new_backing);
2485         }
2486     }
2487 
2488     bdrv_unref(bs);
2489     if (ret) {
2490         return 1;
2491     }
2492     return 0;
2493 }
2494 
2495 static int img_resize(int argc, char **argv)
2496 {
2497     int c, ret, relative;
2498     const char *filename, *fmt, *size;
2499     int64_t n, total_size;
2500     bool quiet = false;
2501     BlockDriverState *bs = NULL;
2502     QemuOpts *param;
2503     static QemuOptsList resize_options = {
2504         .name = "resize_options",
2505         .head = QTAILQ_HEAD_INITIALIZER(resize_options.head),
2506         .desc = {
2507             {
2508                 .name = BLOCK_OPT_SIZE,
2509                 .type = QEMU_OPT_SIZE,
2510                 .help = "Virtual disk size"
2511             }, {
2512                 /* end of list */
2513             }
2514         },
2515     };
2516 
2517     /* Remove size from argv manually so that negative numbers are not treated
2518      * as options by getopt. */
2519     if (argc < 3) {
2520         help();
2521         return 1;
2522     }
2523 
2524     size = argv[--argc];
2525 
2526     /* Parse getopt arguments */
2527     fmt = NULL;
2528     for(;;) {
2529         c = getopt(argc, argv, "f:hq");
2530         if (c == -1) {
2531             break;
2532         }
2533         switch(c) {
2534         case '?':
2535         case 'h':
2536             help();
2537             break;
2538         case 'f':
2539             fmt = optarg;
2540             break;
2541         case 'q':
2542             quiet = true;
2543             break;
2544         }
2545     }
2546     if (optind != argc - 1) {
2547         help();
2548     }
2549     filename = argv[optind++];
2550 
2551     /* Choose grow, shrink, or absolute resize mode */
2552     switch (size[0]) {
2553     case '+':
2554         relative = 1;
2555         size++;
2556         break;
2557     case '-':
2558         relative = -1;
2559         size++;
2560         break;
2561     default:
2562         relative = 0;
2563         break;
2564     }
2565 
2566     /* Parse size */
2567     param = qemu_opts_create(&resize_options, NULL, 0, &error_abort);
2568     if (qemu_opt_set(param, BLOCK_OPT_SIZE, size)) {
2569         /* Error message already printed when size parsing fails */
2570         ret = -1;
2571         qemu_opts_del(param);
2572         goto out;
2573     }
2574     n = qemu_opt_get_size(param, BLOCK_OPT_SIZE, 0);
2575     qemu_opts_del(param);
2576 
2577     bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR, true, quiet);
2578     if (!bs) {
2579         ret = -1;
2580         goto out;
2581     }
2582 
2583     if (relative) {
2584         total_size = bdrv_getlength(bs) + n * relative;
2585     } else {
2586         total_size = n;
2587     }
2588     if (total_size <= 0) {
2589         error_report("New image size must be positive");
2590         ret = -1;
2591         goto out;
2592     }
2593 
2594     ret = bdrv_truncate(bs, total_size);
2595     switch (ret) {
2596     case 0:
2597         qprintf(quiet, "Image resized.\n");
2598         break;
2599     case -ENOTSUP:
2600         error_report("This image does not support resize");
2601         break;
2602     case -EACCES:
2603         error_report("Image is read-only");
2604         break;
2605     default:
2606         error_report("Error resizing image (%d)", -ret);
2607         break;
2608     }
2609 out:
2610     if (bs) {
2611         bdrv_unref(bs);
2612     }
2613     if (ret) {
2614         return 1;
2615     }
2616     return 0;
2617 }
2618 
2619 static int img_amend(int argc, char **argv)
2620 {
2621     int c, ret = 0;
2622     char *options = NULL;
2623     QEMUOptionParameter *create_options = NULL, *options_param = NULL;
2624     const char *fmt = NULL, *filename;
2625     bool quiet = false;
2626     BlockDriverState *bs = NULL;
2627 
2628     for (;;) {
2629         c = getopt(argc, argv, "hqf:o:");
2630         if (c == -1) {
2631             break;
2632         }
2633 
2634         switch (c) {
2635             case 'h':
2636             case '?':
2637                 help();
2638                 break;
2639             case 'o':
2640                 options = optarg;
2641                 break;
2642             case 'f':
2643                 fmt = optarg;
2644                 break;
2645             case 'q':
2646                 quiet = true;
2647                 break;
2648         }
2649     }
2650 
2651     if (optind != argc - 1) {
2652         help();
2653     }
2654 
2655     if (!options) {
2656         help();
2657     }
2658 
2659     filename = argv[argc - 1];
2660 
2661     bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR, true, quiet);
2662     if (!bs) {
2663         error_report("Could not open image '%s'", filename);
2664         ret = -1;
2665         goto out;
2666     }
2667 
2668     fmt = bs->drv->format_name;
2669 
2670     if (is_help_option(options)) {
2671         ret = print_block_option_help(filename, fmt);
2672         goto out;
2673     }
2674 
2675     create_options = append_option_parameters(create_options,
2676             bs->drv->create_options);
2677     options_param = parse_option_parameters(options, create_options,
2678             options_param);
2679     if (options_param == NULL) {
2680         error_report("Invalid options for file format '%s'", fmt);
2681         ret = -1;
2682         goto out;
2683     }
2684 
2685     ret = bdrv_amend_options(bs, options_param);
2686     if (ret < 0) {
2687         error_report("Error while amending options: %s", strerror(-ret));
2688         goto out;
2689     }
2690 
2691 out:
2692     if (bs) {
2693         bdrv_unref(bs);
2694     }
2695     free_option_parameters(create_options);
2696     free_option_parameters(options_param);
2697     if (ret) {
2698         return 1;
2699     }
2700     return 0;
2701 }
2702 
2703 static const img_cmd_t img_cmds[] = {
2704 #define DEF(option, callback, arg_string)        \
2705     { option, callback },
2706 #include "qemu-img-cmds.h"
2707 #undef DEF
2708 #undef GEN_DOCS
2709     { NULL, NULL, },
2710 };
2711 
2712 int main(int argc, char **argv)
2713 {
2714     const img_cmd_t *cmd;
2715     const char *cmdname;
2716 
2717 #ifdef CONFIG_POSIX
2718     signal(SIGPIPE, SIG_IGN);
2719 #endif
2720 
2721     error_set_progname(argv[0]);
2722 
2723     qemu_init_main_loop();
2724     bdrv_init();
2725     if (argc < 2)
2726         help();
2727     cmdname = argv[1];
2728     argc--; argv++;
2729 
2730     /* find the command */
2731     for(cmd = img_cmds; cmd->name != NULL; cmd++) {
2732         if (!strcmp(cmdname, cmd->name)) {
2733             return cmd->handler(argc, argv);
2734         }
2735     }
2736 
2737     /* not found */
2738     help();
2739     return 0;
2740 }
2741