xref: /qemu/qemu-io-cmds.c (revision 7271a819)
1 /*
2  * Command line utility to exercise the QEMU I/O path.
3  *
4  * Copyright (C) 2009-2016 Red Hat, Inc.
5  * Copyright (c) 2003-2005 Silicon Graphics, Inc.
6  *
7  * This work is licensed under the terms of the GNU GPL, version 2 or later.
8  * See the COPYING file in the top-level directory.
9  */
10 
11 #include "qemu/osdep.h"
12 #include "qapi/error.h"
13 #include "qemu-io.h"
14 #include "sysemu/block-backend.h"
15 #include "block/block.h"
16 #include "block/block_int.h" /* for info_f() */
17 #include "block/qapi.h"
18 #include "qemu/error-report.h"
19 #include "qemu/main-loop.h"
20 #include "qemu/timer.h"
21 #include "qemu/cutils.h"
22 
23 #define CMD_NOFILE_OK   0x01
24 
25 bool qemuio_misalign;
26 
27 static cmdinfo_t *cmdtab;
28 static int ncmds;
29 
30 static int compare_cmdname(const void *a, const void *b)
31 {
32     return strcmp(((const cmdinfo_t *)a)->name,
33                   ((const cmdinfo_t *)b)->name);
34 }
35 
36 void qemuio_add_command(const cmdinfo_t *ci)
37 {
38     /* ci->perm assumes a file is open, but the GLOBAL and NOFILE_OK
39      * flags allow it not to be, so that combination is invalid.
40      * Catch it now rather than letting it manifest as a crash if a
41      * particular set of command line options are used.
42      */
43     assert(ci->perm == 0 ||
44            (ci->flags & (CMD_FLAG_GLOBAL | CMD_NOFILE_OK)) == 0);
45     cmdtab = g_renew(cmdinfo_t, cmdtab, ++ncmds);
46     cmdtab[ncmds - 1] = *ci;
47     qsort(cmdtab, ncmds, sizeof(*cmdtab), compare_cmdname);
48 }
49 
50 int qemuio_command_usage(const cmdinfo_t *ci)
51 {
52     printf("%s %s -- %s\n", ci->name, ci->args, ci->oneline);
53     return 0;
54 }
55 
56 static int init_check_command(BlockBackend *blk, const cmdinfo_t *ct)
57 {
58     if (ct->flags & CMD_FLAG_GLOBAL) {
59         return 1;
60     }
61     if (!(ct->flags & CMD_NOFILE_OK) && !blk) {
62         fprintf(stderr, "no file open, try 'help open'\n");
63         return 0;
64     }
65     return 1;
66 }
67 
68 static int command(BlockBackend *blk, const cmdinfo_t *ct, int argc,
69                    char **argv)
70 {
71     char *cmd = argv[0];
72 
73     if (!init_check_command(blk, ct)) {
74         return 0;
75     }
76 
77     if (argc - 1 < ct->argmin || (ct->argmax != -1 && argc - 1 > ct->argmax)) {
78         if (ct->argmax == -1) {
79             fprintf(stderr,
80                     "bad argument count %d to %s, expected at least %d arguments\n",
81                     argc-1, cmd, ct->argmin);
82         } else if (ct->argmin == ct->argmax) {
83             fprintf(stderr,
84                     "bad argument count %d to %s, expected %d arguments\n",
85                     argc-1, cmd, ct->argmin);
86         } else {
87             fprintf(stderr,
88                     "bad argument count %d to %s, expected between %d and %d arguments\n",
89                     argc-1, cmd, ct->argmin, ct->argmax);
90         }
91         return 0;
92     }
93 
94     /* Request additional permissions if necessary for this command. The caller
95      * is responsible for restoring the original permissions afterwards if this
96      * is what it wants. */
97     if (ct->perm && blk_is_available(blk)) {
98         uint64_t orig_perm, orig_shared_perm;
99         blk_get_perm(blk, &orig_perm, &orig_shared_perm);
100 
101         if (ct->perm & ~orig_perm) {
102             uint64_t new_perm;
103             Error *local_err = NULL;
104             int ret;
105 
106             new_perm = orig_perm | ct->perm;
107 
108             ret = blk_set_perm(blk, new_perm, orig_shared_perm, &local_err);
109             if (ret < 0) {
110                 error_report_err(local_err);
111                 return 0;
112             }
113         }
114     }
115 
116     optind = 0;
117     return ct->cfunc(blk, argc, argv);
118 }
119 
120 static const cmdinfo_t *find_command(const char *cmd)
121 {
122     cmdinfo_t *ct;
123 
124     for (ct = cmdtab; ct < &cmdtab[ncmds]; ct++) {
125         if (strcmp(ct->name, cmd) == 0 ||
126             (ct->altname && strcmp(ct->altname, cmd) == 0))
127         {
128             return (const cmdinfo_t *)ct;
129         }
130     }
131     return NULL;
132 }
133 
134 /* Invoke fn() for commands with a matching prefix */
135 void qemuio_complete_command(const char *input,
136                              void (*fn)(const char *cmd, void *opaque),
137                              void *opaque)
138 {
139     cmdinfo_t *ct;
140     size_t input_len = strlen(input);
141 
142     for (ct = cmdtab; ct < &cmdtab[ncmds]; ct++) {
143         if (strncmp(input, ct->name, input_len) == 0) {
144             fn(ct->name, opaque);
145         }
146     }
147 }
148 
149 static char **breakline(char *input, int *count)
150 {
151     int c = 0;
152     char *p;
153     char **rval = g_new0(char *, 1);
154 
155     while (rval && (p = qemu_strsep(&input, " ")) != NULL) {
156         if (!*p) {
157             continue;
158         }
159         c++;
160         rval = g_renew(char *, rval, (c + 1));
161         rval[c - 1] = p;
162         rval[c] = NULL;
163     }
164     *count = c;
165     return rval;
166 }
167 
168 static int64_t cvtnum(const char *s)
169 {
170     int err;
171     uint64_t value;
172 
173     err = qemu_strtosz(s, NULL, &value);
174     if (err < 0) {
175         return err;
176     }
177     if (value > INT64_MAX) {
178         return -ERANGE;
179     }
180     return value;
181 }
182 
183 static void print_cvtnum_err(int64_t rc, const char *arg)
184 {
185     switch (rc) {
186     case -EINVAL:
187         printf("Parsing error: non-numeric argument,"
188                " or extraneous/unrecognized suffix -- %s\n", arg);
189         break;
190     case -ERANGE:
191         printf("Parsing error: argument too large -- %s\n", arg);
192         break;
193     default:
194         printf("Parsing error: %s\n", arg);
195     }
196 }
197 
198 #define EXABYTES(x)     ((long long)(x) << 60)
199 #define PETABYTES(x)    ((long long)(x) << 50)
200 #define TERABYTES(x)    ((long long)(x) << 40)
201 #define GIGABYTES(x)    ((long long)(x) << 30)
202 #define MEGABYTES(x)    ((long long)(x) << 20)
203 #define KILOBYTES(x)    ((long long)(x) << 10)
204 
205 #define TO_EXABYTES(x)  ((x) / EXABYTES(1))
206 #define TO_PETABYTES(x) ((x) / PETABYTES(1))
207 #define TO_TERABYTES(x) ((x) / TERABYTES(1))
208 #define TO_GIGABYTES(x) ((x) / GIGABYTES(1))
209 #define TO_MEGABYTES(x) ((x) / MEGABYTES(1))
210 #define TO_KILOBYTES(x) ((x) / KILOBYTES(1))
211 
212 static void cvtstr(double value, char *str, size_t size)
213 {
214     char *trim;
215     const char *suffix;
216 
217     if (value >= EXABYTES(1)) {
218         suffix = " EiB";
219         snprintf(str, size - 4, "%.3f", TO_EXABYTES(value));
220     } else if (value >= PETABYTES(1)) {
221         suffix = " PiB";
222         snprintf(str, size - 4, "%.3f", TO_PETABYTES(value));
223     } else if (value >= TERABYTES(1)) {
224         suffix = " TiB";
225         snprintf(str, size - 4, "%.3f", TO_TERABYTES(value));
226     } else if (value >= GIGABYTES(1)) {
227         suffix = " GiB";
228         snprintf(str, size - 4, "%.3f", TO_GIGABYTES(value));
229     } else if (value >= MEGABYTES(1)) {
230         suffix = " MiB";
231         snprintf(str, size - 4, "%.3f", TO_MEGABYTES(value));
232     } else if (value >= KILOBYTES(1)) {
233         suffix = " KiB";
234         snprintf(str, size - 4, "%.3f", TO_KILOBYTES(value));
235     } else {
236         suffix = " bytes";
237         snprintf(str, size - 6, "%f", value);
238     }
239 
240     trim = strstr(str, ".000");
241     if (trim) {
242         strcpy(trim, suffix);
243     } else {
244         strcat(str, suffix);
245     }
246 }
247 
248 
249 
250 static struct timeval tsub(struct timeval t1, struct timeval t2)
251 {
252     t1.tv_usec -= t2.tv_usec;
253     if (t1.tv_usec < 0) {
254         t1.tv_usec += 1000000;
255         t1.tv_sec--;
256     }
257     t1.tv_sec -= t2.tv_sec;
258     return t1;
259 }
260 
261 static double tdiv(double value, struct timeval tv)
262 {
263     return value / ((double)tv.tv_sec + ((double)tv.tv_usec / 1000000.0));
264 }
265 
266 #define HOURS(sec)      ((sec) / (60 * 60))
267 #define MINUTES(sec)    (((sec) % (60 * 60)) / 60)
268 #define SECONDS(sec)    ((sec) % 60)
269 
270 enum {
271     DEFAULT_TIME        = 0x0,
272     TERSE_FIXED_TIME    = 0x1,
273     VERBOSE_FIXED_TIME  = 0x2,
274 };
275 
276 static void timestr(struct timeval *tv, char *ts, size_t size, int format)
277 {
278     double usec = (double)tv->tv_usec / 1000000.0;
279 
280     if (format & TERSE_FIXED_TIME) {
281         if (!HOURS(tv->tv_sec)) {
282             snprintf(ts, size, "%u:%02u.%02u",
283                     (unsigned int) MINUTES(tv->tv_sec),
284                     (unsigned int) SECONDS(tv->tv_sec),
285                     (unsigned int) (usec * 100));
286             return;
287         }
288         format |= VERBOSE_FIXED_TIME; /* fallback if hours needed */
289     }
290 
291     if ((format & VERBOSE_FIXED_TIME) || tv->tv_sec) {
292         snprintf(ts, size, "%u:%02u:%02u.%02u",
293                 (unsigned int) HOURS(tv->tv_sec),
294                 (unsigned int) MINUTES(tv->tv_sec),
295                 (unsigned int) SECONDS(tv->tv_sec),
296                 (unsigned int) (usec * 100));
297     } else {
298         snprintf(ts, size, "0.%04u sec", (unsigned int) (usec * 10000));
299     }
300 }
301 
302 /*
303  * Parse the pattern argument to various sub-commands.
304  *
305  * Because the pattern is used as an argument to memset it must evaluate
306  * to an unsigned integer that fits into a single byte.
307  */
308 static int parse_pattern(const char *arg)
309 {
310     char *endptr = NULL;
311     long pattern;
312 
313     pattern = strtol(arg, &endptr, 0);
314     if (pattern < 0 || pattern > UCHAR_MAX || *endptr != '\0') {
315         printf("%s is not a valid pattern byte\n", arg);
316         return -1;
317     }
318 
319     return pattern;
320 }
321 
322 /*
323  * Memory allocation helpers.
324  *
325  * Make sure memory is aligned by default, or purposefully misaligned if
326  * that is specified on the command line.
327  */
328 
329 #define MISALIGN_OFFSET     16
330 static void *qemu_io_alloc(BlockBackend *blk, size_t len, int pattern)
331 {
332     void *buf;
333 
334     if (qemuio_misalign) {
335         len += MISALIGN_OFFSET;
336     }
337     buf = blk_blockalign(blk, len);
338     memset(buf, pattern, len);
339     if (qemuio_misalign) {
340         buf += MISALIGN_OFFSET;
341     }
342     return buf;
343 }
344 
345 static void qemu_io_free(void *p)
346 {
347     if (qemuio_misalign) {
348         p -= MISALIGN_OFFSET;
349     }
350     qemu_vfree(p);
351 }
352 
353 static void dump_buffer(const void *buffer, int64_t offset, int64_t len)
354 {
355     uint64_t i;
356     int j;
357     const uint8_t *p;
358 
359     for (i = 0, p = buffer; i < len; i += 16) {
360         const uint8_t *s = p;
361 
362         printf("%08" PRIx64 ":  ", offset + i);
363         for (j = 0; j < 16 && i + j < len; j++, p++) {
364             printf("%02x ", *p);
365         }
366         printf(" ");
367         for (j = 0; j < 16 && i + j < len; j++, s++) {
368             if (isalnum(*s)) {
369                 printf("%c", *s);
370             } else {
371                 printf(".");
372             }
373         }
374         printf("\n");
375     }
376 }
377 
378 static void print_report(const char *op, struct timeval *t, int64_t offset,
379                          int64_t count, int64_t total, int cnt, bool Cflag)
380 {
381     char s1[64], s2[64], ts[64];
382 
383     timestr(t, ts, sizeof(ts), Cflag ? VERBOSE_FIXED_TIME : 0);
384     if (!Cflag) {
385         cvtstr((double)total, s1, sizeof(s1));
386         cvtstr(tdiv((double)total, *t), s2, sizeof(s2));
387         printf("%s %"PRId64"/%"PRId64" bytes at offset %" PRId64 "\n",
388                op, total, count, offset);
389         printf("%s, %d ops; %s (%s/sec and %.4f ops/sec)\n",
390                s1, cnt, ts, s2, tdiv((double)cnt, *t));
391     } else {/* bytes,ops,time,bytes/sec,ops/sec */
392         printf("%"PRId64",%d,%s,%.3f,%.3f\n",
393             total, cnt, ts,
394             tdiv((double)total, *t),
395             tdiv((double)cnt, *t));
396     }
397 }
398 
399 /*
400  * Parse multiple length statements for vectored I/O, and construct an I/O
401  * vector matching it.
402  */
403 static void *
404 create_iovec(BlockBackend *blk, QEMUIOVector *qiov, char **argv, int nr_iov,
405              int pattern)
406 {
407     size_t *sizes = g_new0(size_t, nr_iov);
408     size_t count = 0;
409     void *buf = NULL;
410     void *p;
411     int i;
412 
413     for (i = 0; i < nr_iov; i++) {
414         char *arg = argv[i];
415         int64_t len;
416 
417         len = cvtnum(arg);
418         if (len < 0) {
419             print_cvtnum_err(len, arg);
420             goto fail;
421         }
422 
423         if (len > BDRV_REQUEST_MAX_BYTES) {
424             printf("Argument '%s' exceeds maximum size %" PRIu64 "\n", arg,
425                    (uint64_t)BDRV_REQUEST_MAX_BYTES);
426             goto fail;
427         }
428 
429         if (count > BDRV_REQUEST_MAX_BYTES - len) {
430             printf("The total number of bytes exceed the maximum size %" PRIu64
431                    "\n", (uint64_t)BDRV_REQUEST_MAX_BYTES);
432             goto fail;
433         }
434 
435         sizes[i] = len;
436         count += len;
437     }
438 
439     qemu_iovec_init(qiov, nr_iov);
440 
441     buf = p = qemu_io_alloc(blk, count, pattern);
442 
443     for (i = 0; i < nr_iov; i++) {
444         qemu_iovec_add(qiov, p, sizes[i]);
445         p += sizes[i];
446     }
447 
448 fail:
449     g_free(sizes);
450     return buf;
451 }
452 
453 static int do_pread(BlockBackend *blk, char *buf, int64_t offset,
454                     int64_t bytes, int64_t *total)
455 {
456     if (bytes > INT_MAX) {
457         return -ERANGE;
458     }
459 
460     *total = blk_pread(blk, offset, (uint8_t *)buf, bytes);
461     if (*total < 0) {
462         return *total;
463     }
464     return 1;
465 }
466 
467 static int do_pwrite(BlockBackend *blk, char *buf, int64_t offset,
468                      int64_t bytes, int flags, int64_t *total)
469 {
470     if (bytes > INT_MAX) {
471         return -ERANGE;
472     }
473 
474     *total = blk_pwrite(blk, offset, (uint8_t *)buf, bytes, flags);
475     if (*total < 0) {
476         return *total;
477     }
478     return 1;
479 }
480 
481 typedef struct {
482     BlockBackend *blk;
483     int64_t offset;
484     int64_t bytes;
485     int64_t *total;
486     int flags;
487     int ret;
488     bool done;
489 } CoWriteZeroes;
490 
491 static void coroutine_fn co_pwrite_zeroes_entry(void *opaque)
492 {
493     CoWriteZeroes *data = opaque;
494 
495     data->ret = blk_co_pwrite_zeroes(data->blk, data->offset, data->bytes,
496                                      data->flags);
497     data->done = true;
498     if (data->ret < 0) {
499         *data->total = data->ret;
500         return;
501     }
502 
503     *data->total = data->bytes;
504 }
505 
506 static int do_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
507                                int64_t bytes, int flags, int64_t *total)
508 {
509     Coroutine *co;
510     CoWriteZeroes data = {
511         .blk    = blk,
512         .offset = offset,
513         .bytes  = bytes,
514         .total  = total,
515         .flags  = flags,
516         .done   = false,
517     };
518 
519     if (bytes > INT_MAX) {
520         return -ERANGE;
521     }
522 
523     co = qemu_coroutine_create(co_pwrite_zeroes_entry, &data);
524     bdrv_coroutine_enter(blk_bs(blk), co);
525     while (!data.done) {
526         aio_poll(blk_get_aio_context(blk), true);
527     }
528     if (data.ret < 0) {
529         return data.ret;
530     } else {
531         return 1;
532     }
533 }
534 
535 static int do_write_compressed(BlockBackend *blk, char *buf, int64_t offset,
536                                int64_t bytes, int64_t *total)
537 {
538     int ret;
539 
540     if (bytes >> 9 > BDRV_REQUEST_MAX_SECTORS) {
541         return -ERANGE;
542     }
543 
544     ret = blk_pwrite_compressed(blk, offset, buf, bytes);
545     if (ret < 0) {
546         return ret;
547     }
548     *total = bytes;
549     return 1;
550 }
551 
552 static int do_load_vmstate(BlockBackend *blk, char *buf, int64_t offset,
553                            int64_t count, int64_t *total)
554 {
555     if (count > INT_MAX) {
556         return -ERANGE;
557     }
558 
559     *total = blk_load_vmstate(blk, (uint8_t *)buf, offset, count);
560     if (*total < 0) {
561         return *total;
562     }
563     return 1;
564 }
565 
566 static int do_save_vmstate(BlockBackend *blk, char *buf, int64_t offset,
567                            int64_t count, int64_t *total)
568 {
569     if (count > INT_MAX) {
570         return -ERANGE;
571     }
572 
573     *total = blk_save_vmstate(blk, (uint8_t *)buf, offset, count);
574     if (*total < 0) {
575         return *total;
576     }
577     return 1;
578 }
579 
580 #define NOT_DONE 0x7fffffff
581 static void aio_rw_done(void *opaque, int ret)
582 {
583     *(int *)opaque = ret;
584 }
585 
586 static int do_aio_readv(BlockBackend *blk, QEMUIOVector *qiov,
587                         int64_t offset, int *total)
588 {
589     int async_ret = NOT_DONE;
590 
591     blk_aio_preadv(blk, offset, qiov, 0, aio_rw_done, &async_ret);
592     while (async_ret == NOT_DONE) {
593         main_loop_wait(false);
594     }
595 
596     *total = qiov->size;
597     return async_ret < 0 ? async_ret : 1;
598 }
599 
600 static int do_aio_writev(BlockBackend *blk, QEMUIOVector *qiov,
601                          int64_t offset, int flags, int *total)
602 {
603     int async_ret = NOT_DONE;
604 
605     blk_aio_pwritev(blk, offset, qiov, flags, aio_rw_done, &async_ret);
606     while (async_ret == NOT_DONE) {
607         main_loop_wait(false);
608     }
609 
610     *total = qiov->size;
611     return async_ret < 0 ? async_ret : 1;
612 }
613 
614 static void read_help(void)
615 {
616     printf(
617 "\n"
618 " reads a range of bytes from the given offset\n"
619 "\n"
620 " Example:\n"
621 " 'read -v 512 1k' - dumps 1 kilobyte read from 512 bytes into the file\n"
622 "\n"
623 " Reads a segment of the currently open file, optionally dumping it to the\n"
624 " standard output stream (with -v option) for subsequent inspection.\n"
625 " -b, -- read from the VM state rather than the virtual disk\n"
626 " -C, -- report statistics in a machine parsable format\n"
627 " -l, -- length for pattern verification (only with -P)\n"
628 " -p, -- ignored for backwards compatibility\n"
629 " -P, -- use a pattern to verify read data\n"
630 " -q, -- quiet mode, do not show I/O statistics\n"
631 " -s, -- start offset for pattern verification (only with -P)\n"
632 " -v, -- dump buffer to standard output\n"
633 "\n");
634 }
635 
636 static int read_f(BlockBackend *blk, int argc, char **argv);
637 
638 static const cmdinfo_t read_cmd = {
639     .name       = "read",
640     .altname    = "r",
641     .cfunc      = read_f,
642     .argmin     = 2,
643     .argmax     = -1,
644     .args       = "[-abCqv] [-P pattern [-s off] [-l len]] off len",
645     .oneline    = "reads a number of bytes at a specified offset",
646     .help       = read_help,
647 };
648 
649 static int read_f(BlockBackend *blk, int argc, char **argv)
650 {
651     struct timeval t1, t2;
652     bool Cflag = false, qflag = false, vflag = false;
653     bool Pflag = false, sflag = false, lflag = false, bflag = false;
654     int c, cnt;
655     char *buf;
656     int64_t offset;
657     int64_t count;
658     /* Some compilers get confused and warn if this is not initialized.  */
659     int64_t total = 0;
660     int pattern = 0;
661     int64_t pattern_offset = 0, pattern_count = 0;
662 
663     while ((c = getopt(argc, argv, "bCl:pP:qs:v")) != -1) {
664         switch (c) {
665         case 'b':
666             bflag = true;
667             break;
668         case 'C':
669             Cflag = true;
670             break;
671         case 'l':
672             lflag = true;
673             pattern_count = cvtnum(optarg);
674             if (pattern_count < 0) {
675                 print_cvtnum_err(pattern_count, optarg);
676                 return 0;
677             }
678             break;
679         case 'p':
680             /* Ignored for backwards compatibility */
681             break;
682         case 'P':
683             Pflag = true;
684             pattern = parse_pattern(optarg);
685             if (pattern < 0) {
686                 return 0;
687             }
688             break;
689         case 'q':
690             qflag = true;
691             break;
692         case 's':
693             sflag = true;
694             pattern_offset = cvtnum(optarg);
695             if (pattern_offset < 0) {
696                 print_cvtnum_err(pattern_offset, optarg);
697                 return 0;
698             }
699             break;
700         case 'v':
701             vflag = true;
702             break;
703         default:
704             return qemuio_command_usage(&read_cmd);
705         }
706     }
707 
708     if (optind != argc - 2) {
709         return qemuio_command_usage(&read_cmd);
710     }
711 
712     offset = cvtnum(argv[optind]);
713     if (offset < 0) {
714         print_cvtnum_err(offset, argv[optind]);
715         return 0;
716     }
717 
718     optind++;
719     count = cvtnum(argv[optind]);
720     if (count < 0) {
721         print_cvtnum_err(count, argv[optind]);
722         return 0;
723     } else if (count > BDRV_REQUEST_MAX_BYTES) {
724         printf("length cannot exceed %" PRIu64 ", given %s\n",
725                (uint64_t)BDRV_REQUEST_MAX_BYTES, argv[optind]);
726         return 0;
727     }
728 
729     if (!Pflag && (lflag || sflag)) {
730         return qemuio_command_usage(&read_cmd);
731     }
732 
733     if (!lflag) {
734         pattern_count = count - pattern_offset;
735     }
736 
737     if ((pattern_count < 0) || (pattern_count + pattern_offset > count))  {
738         printf("pattern verification range exceeds end of read data\n");
739         return 0;
740     }
741 
742     if (bflag) {
743         if (!QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)) {
744             printf("%" PRId64 " is not a sector-aligned value for 'offset'\n",
745                    offset);
746             return 0;
747         }
748         if (!QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)) {
749             printf("%"PRId64" is not a sector-aligned value for 'count'\n",
750                    count);
751             return 0;
752         }
753     }
754 
755     buf = qemu_io_alloc(blk, count, 0xab);
756 
757     gettimeofday(&t1, NULL);
758     if (bflag) {
759         cnt = do_load_vmstate(blk, buf, offset, count, &total);
760     } else {
761         cnt = do_pread(blk, buf, offset, count, &total);
762     }
763     gettimeofday(&t2, NULL);
764 
765     if (cnt < 0) {
766         printf("read failed: %s\n", strerror(-cnt));
767         goto out;
768     }
769 
770     if (Pflag) {
771         void *cmp_buf = g_malloc(pattern_count);
772         memset(cmp_buf, pattern, pattern_count);
773         if (memcmp(buf + pattern_offset, cmp_buf, pattern_count)) {
774             printf("Pattern verification failed at offset %"
775                    PRId64 ", %"PRId64" bytes\n",
776                    offset + pattern_offset, pattern_count);
777         }
778         g_free(cmp_buf);
779     }
780 
781     if (qflag) {
782         goto out;
783     }
784 
785     if (vflag) {
786         dump_buffer(buf, offset, count);
787     }
788 
789     /* Finally, report back -- -C gives a parsable format */
790     t2 = tsub(t2, t1);
791     print_report("read", &t2, offset, count, total, cnt, Cflag);
792 
793 out:
794     qemu_io_free(buf);
795 
796     return 0;
797 }
798 
799 static void readv_help(void)
800 {
801     printf(
802 "\n"
803 " reads a range of bytes from the given offset into multiple buffers\n"
804 "\n"
805 " Example:\n"
806 " 'readv -v 512 1k 1k ' - dumps 2 kilobytes read from 512 bytes into the file\n"
807 "\n"
808 " Reads a segment of the currently open file, optionally dumping it to the\n"
809 " standard output stream (with -v option) for subsequent inspection.\n"
810 " Uses multiple iovec buffers if more than one byte range is specified.\n"
811 " -C, -- report statistics in a machine parsable format\n"
812 " -P, -- use a pattern to verify read data\n"
813 " -v, -- dump buffer to standard output\n"
814 " -q, -- quiet mode, do not show I/O statistics\n"
815 "\n");
816 }
817 
818 static int readv_f(BlockBackend *blk, int argc, char **argv);
819 
820 static const cmdinfo_t readv_cmd = {
821     .name       = "readv",
822     .cfunc      = readv_f,
823     .argmin     = 2,
824     .argmax     = -1,
825     .args       = "[-Cqv] [-P pattern] off len [len..]",
826     .oneline    = "reads a number of bytes at a specified offset",
827     .help       = readv_help,
828 };
829 
830 static int readv_f(BlockBackend *blk, int argc, char **argv)
831 {
832     struct timeval t1, t2;
833     bool Cflag = false, qflag = false, vflag = false;
834     int c, cnt;
835     char *buf;
836     int64_t offset;
837     /* Some compilers get confused and warn if this is not initialized.  */
838     int total = 0;
839     int nr_iov;
840     QEMUIOVector qiov;
841     int pattern = 0;
842     bool Pflag = false;
843 
844     while ((c = getopt(argc, argv, "CP:qv")) != -1) {
845         switch (c) {
846         case 'C':
847             Cflag = true;
848             break;
849         case 'P':
850             Pflag = true;
851             pattern = parse_pattern(optarg);
852             if (pattern < 0) {
853                 return 0;
854             }
855             break;
856         case 'q':
857             qflag = true;
858             break;
859         case 'v':
860             vflag = true;
861             break;
862         default:
863             return qemuio_command_usage(&readv_cmd);
864         }
865     }
866 
867     if (optind > argc - 2) {
868         return qemuio_command_usage(&readv_cmd);
869     }
870 
871 
872     offset = cvtnum(argv[optind]);
873     if (offset < 0) {
874         print_cvtnum_err(offset, argv[optind]);
875         return 0;
876     }
877     optind++;
878 
879     nr_iov = argc - optind;
880     buf = create_iovec(blk, &qiov, &argv[optind], nr_iov, 0xab);
881     if (buf == NULL) {
882         return 0;
883     }
884 
885     gettimeofday(&t1, NULL);
886     cnt = do_aio_readv(blk, &qiov, offset, &total);
887     gettimeofday(&t2, NULL);
888 
889     if (cnt < 0) {
890         printf("readv failed: %s\n", strerror(-cnt));
891         goto out;
892     }
893 
894     if (Pflag) {
895         void *cmp_buf = g_malloc(qiov.size);
896         memset(cmp_buf, pattern, qiov.size);
897         if (memcmp(buf, cmp_buf, qiov.size)) {
898             printf("Pattern verification failed at offset %"
899                    PRId64 ", %zd bytes\n", offset, qiov.size);
900         }
901         g_free(cmp_buf);
902     }
903 
904     if (qflag) {
905         goto out;
906     }
907 
908     if (vflag) {
909         dump_buffer(buf, offset, qiov.size);
910     }
911 
912     /* Finally, report back -- -C gives a parsable format */
913     t2 = tsub(t2, t1);
914     print_report("read", &t2, offset, qiov.size, total, cnt, Cflag);
915 
916 out:
917     qemu_iovec_destroy(&qiov);
918     qemu_io_free(buf);
919     return 0;
920 }
921 
922 static void write_help(void)
923 {
924     printf(
925 "\n"
926 " writes a range of bytes from the given offset\n"
927 "\n"
928 " Example:\n"
929 " 'write 512 1k' - writes 1 kilobyte at 512 bytes into the open file\n"
930 "\n"
931 " Writes into a segment of the currently open file, using a buffer\n"
932 " filled with a set pattern (0xcdcdcdcd).\n"
933 " -b, -- write to the VM state rather than the virtual disk\n"
934 " -c, -- write compressed data with blk_write_compressed\n"
935 " -f, -- use Force Unit Access semantics\n"
936 " -p, -- ignored for backwards compatibility\n"
937 " -P, -- use different pattern to fill file\n"
938 " -C, -- report statistics in a machine parsable format\n"
939 " -q, -- quiet mode, do not show I/O statistics\n"
940 " -u, -- with -z, allow unmapping\n"
941 " -z, -- write zeroes using blk_co_pwrite_zeroes\n"
942 "\n");
943 }
944 
945 static int write_f(BlockBackend *blk, int argc, char **argv);
946 
947 static const cmdinfo_t write_cmd = {
948     .name       = "write",
949     .altname    = "w",
950     .cfunc      = write_f,
951     .perm       = BLK_PERM_WRITE,
952     .argmin     = 2,
953     .argmax     = -1,
954     .args       = "[-bcCfquz] [-P pattern] off len",
955     .oneline    = "writes a number of bytes at a specified offset",
956     .help       = write_help,
957 };
958 
959 static int write_f(BlockBackend *blk, int argc, char **argv)
960 {
961     struct timeval t1, t2;
962     bool Cflag = false, qflag = false, bflag = false;
963     bool Pflag = false, zflag = false, cflag = false;
964     int flags = 0;
965     int c, cnt;
966     char *buf = NULL;
967     int64_t offset;
968     int64_t count;
969     /* Some compilers get confused and warn if this is not initialized.  */
970     int64_t total = 0;
971     int pattern = 0xcd;
972 
973     while ((c = getopt(argc, argv, "bcCfpP:quz")) != -1) {
974         switch (c) {
975         case 'b':
976             bflag = true;
977             break;
978         case 'c':
979             cflag = true;
980             break;
981         case 'C':
982             Cflag = true;
983             break;
984         case 'f':
985             flags |= BDRV_REQ_FUA;
986             break;
987         case 'p':
988             /* Ignored for backwards compatibility */
989             break;
990         case 'P':
991             Pflag = true;
992             pattern = parse_pattern(optarg);
993             if (pattern < 0) {
994                 return 0;
995             }
996             break;
997         case 'q':
998             qflag = true;
999             break;
1000         case 'u':
1001             flags |= BDRV_REQ_MAY_UNMAP;
1002             break;
1003         case 'z':
1004             zflag = true;
1005             break;
1006         default:
1007             return qemuio_command_usage(&write_cmd);
1008         }
1009     }
1010 
1011     if (optind != argc - 2) {
1012         return qemuio_command_usage(&write_cmd);
1013     }
1014 
1015     if (bflag && zflag) {
1016         printf("-b and -z cannot be specified at the same time\n");
1017         return 0;
1018     }
1019 
1020     if ((flags & BDRV_REQ_FUA) && (bflag || cflag)) {
1021         printf("-f and -b or -c cannot be specified at the same time\n");
1022         return 0;
1023     }
1024 
1025     if ((flags & BDRV_REQ_MAY_UNMAP) && !zflag) {
1026         printf("-u requires -z to be specified\n");
1027         return 0;
1028     }
1029 
1030     if (zflag && Pflag) {
1031         printf("-z and -P cannot be specified at the same time\n");
1032         return 0;
1033     }
1034 
1035     offset = cvtnum(argv[optind]);
1036     if (offset < 0) {
1037         print_cvtnum_err(offset, argv[optind]);
1038         return 0;
1039     }
1040 
1041     optind++;
1042     count = cvtnum(argv[optind]);
1043     if (count < 0) {
1044         print_cvtnum_err(count, argv[optind]);
1045         return 0;
1046     } else if (count > BDRV_REQUEST_MAX_BYTES) {
1047         printf("length cannot exceed %" PRIu64 ", given %s\n",
1048                (uint64_t)BDRV_REQUEST_MAX_BYTES, argv[optind]);
1049         return 0;
1050     }
1051 
1052     if (bflag || cflag) {
1053         if (!QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)) {
1054             printf("%" PRId64 " is not a sector-aligned value for 'offset'\n",
1055                    offset);
1056             return 0;
1057         }
1058 
1059         if (!QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)) {
1060             printf("%"PRId64" is not a sector-aligned value for 'count'\n",
1061                    count);
1062             return 0;
1063         }
1064     }
1065 
1066     if (!zflag) {
1067         buf = qemu_io_alloc(blk, count, pattern);
1068     }
1069 
1070     gettimeofday(&t1, NULL);
1071     if (bflag) {
1072         cnt = do_save_vmstate(blk, buf, offset, count, &total);
1073     } else if (zflag) {
1074         cnt = do_co_pwrite_zeroes(blk, offset, count, flags, &total);
1075     } else if (cflag) {
1076         cnt = do_write_compressed(blk, buf, offset, count, &total);
1077     } else {
1078         cnt = do_pwrite(blk, buf, offset, count, flags, &total);
1079     }
1080     gettimeofday(&t2, NULL);
1081 
1082     if (cnt < 0) {
1083         printf("write failed: %s\n", strerror(-cnt));
1084         goto out;
1085     }
1086 
1087     if (qflag) {
1088         goto out;
1089     }
1090 
1091     /* Finally, report back -- -C gives a parsable format */
1092     t2 = tsub(t2, t1);
1093     print_report("wrote", &t2, offset, count, total, cnt, Cflag);
1094 
1095 out:
1096     if (!zflag) {
1097         qemu_io_free(buf);
1098     }
1099 
1100     return 0;
1101 }
1102 
1103 static void
1104 writev_help(void)
1105 {
1106     printf(
1107 "\n"
1108 " writes a range of bytes from the given offset source from multiple buffers\n"
1109 "\n"
1110 " Example:\n"
1111 " 'writev 512 1k 1k' - writes 2 kilobytes at 512 bytes into the open file\n"
1112 "\n"
1113 " Writes into a segment of the currently open file, using a buffer\n"
1114 " filled with a set pattern (0xcdcdcdcd).\n"
1115 " -P, -- use different pattern to fill file\n"
1116 " -C, -- report statistics in a machine parsable format\n"
1117 " -f, -- use Force Unit Access semantics\n"
1118 " -q, -- quiet mode, do not show I/O statistics\n"
1119 "\n");
1120 }
1121 
1122 static int writev_f(BlockBackend *blk, int argc, char **argv);
1123 
1124 static const cmdinfo_t writev_cmd = {
1125     .name       = "writev",
1126     .cfunc      = writev_f,
1127     .perm       = BLK_PERM_WRITE,
1128     .argmin     = 2,
1129     .argmax     = -1,
1130     .args       = "[-Cfq] [-P pattern] off len [len..]",
1131     .oneline    = "writes a number of bytes at a specified offset",
1132     .help       = writev_help,
1133 };
1134 
1135 static int writev_f(BlockBackend *blk, int argc, char **argv)
1136 {
1137     struct timeval t1, t2;
1138     bool Cflag = false, qflag = false;
1139     int flags = 0;
1140     int c, cnt;
1141     char *buf;
1142     int64_t offset;
1143     /* Some compilers get confused and warn if this is not initialized.  */
1144     int total = 0;
1145     int nr_iov;
1146     int pattern = 0xcd;
1147     QEMUIOVector qiov;
1148 
1149     while ((c = getopt(argc, argv, "CfqP:")) != -1) {
1150         switch (c) {
1151         case 'C':
1152             Cflag = true;
1153             break;
1154         case 'f':
1155             flags |= BDRV_REQ_FUA;
1156             break;
1157         case 'q':
1158             qflag = true;
1159             break;
1160         case 'P':
1161             pattern = parse_pattern(optarg);
1162             if (pattern < 0) {
1163                 return 0;
1164             }
1165             break;
1166         default:
1167             return qemuio_command_usage(&writev_cmd);
1168         }
1169     }
1170 
1171     if (optind > argc - 2) {
1172         return qemuio_command_usage(&writev_cmd);
1173     }
1174 
1175     offset = cvtnum(argv[optind]);
1176     if (offset < 0) {
1177         print_cvtnum_err(offset, argv[optind]);
1178         return 0;
1179     }
1180     optind++;
1181 
1182     nr_iov = argc - optind;
1183     buf = create_iovec(blk, &qiov, &argv[optind], nr_iov, pattern);
1184     if (buf == NULL) {
1185         return 0;
1186     }
1187 
1188     gettimeofday(&t1, NULL);
1189     cnt = do_aio_writev(blk, &qiov, offset, flags, &total);
1190     gettimeofday(&t2, NULL);
1191 
1192     if (cnt < 0) {
1193         printf("writev failed: %s\n", strerror(-cnt));
1194         goto out;
1195     }
1196 
1197     if (qflag) {
1198         goto out;
1199     }
1200 
1201     /* Finally, report back -- -C gives a parsable format */
1202     t2 = tsub(t2, t1);
1203     print_report("wrote", &t2, offset, qiov.size, total, cnt, Cflag);
1204 out:
1205     qemu_iovec_destroy(&qiov);
1206     qemu_io_free(buf);
1207     return 0;
1208 }
1209 
1210 struct aio_ctx {
1211     BlockBackend *blk;
1212     QEMUIOVector qiov;
1213     int64_t offset;
1214     char *buf;
1215     bool qflag;
1216     bool vflag;
1217     bool Cflag;
1218     bool Pflag;
1219     bool zflag;
1220     BlockAcctCookie acct;
1221     int pattern;
1222     struct timeval t1;
1223 };
1224 
1225 static void aio_write_done(void *opaque, int ret)
1226 {
1227     struct aio_ctx *ctx = opaque;
1228     struct timeval t2;
1229 
1230     gettimeofday(&t2, NULL);
1231 
1232 
1233     if (ret < 0) {
1234         printf("aio_write failed: %s\n", strerror(-ret));
1235         block_acct_failed(blk_get_stats(ctx->blk), &ctx->acct);
1236         goto out;
1237     }
1238 
1239     block_acct_done(blk_get_stats(ctx->blk), &ctx->acct);
1240 
1241     if (ctx->qflag) {
1242         goto out;
1243     }
1244 
1245     /* Finally, report back -- -C gives a parsable format */
1246     t2 = tsub(t2, ctx->t1);
1247     print_report("wrote", &t2, ctx->offset, ctx->qiov.size,
1248                  ctx->qiov.size, 1, ctx->Cflag);
1249 out:
1250     if (!ctx->zflag) {
1251         qemu_io_free(ctx->buf);
1252         qemu_iovec_destroy(&ctx->qiov);
1253     }
1254     g_free(ctx);
1255 }
1256 
1257 static void aio_read_done(void *opaque, int ret)
1258 {
1259     struct aio_ctx *ctx = opaque;
1260     struct timeval t2;
1261 
1262     gettimeofday(&t2, NULL);
1263 
1264     if (ret < 0) {
1265         printf("readv failed: %s\n", strerror(-ret));
1266         block_acct_failed(blk_get_stats(ctx->blk), &ctx->acct);
1267         goto out;
1268     }
1269 
1270     if (ctx->Pflag) {
1271         void *cmp_buf = g_malloc(ctx->qiov.size);
1272 
1273         memset(cmp_buf, ctx->pattern, ctx->qiov.size);
1274         if (memcmp(ctx->buf, cmp_buf, ctx->qiov.size)) {
1275             printf("Pattern verification failed at offset %"
1276                    PRId64 ", %zd bytes\n", ctx->offset, ctx->qiov.size);
1277         }
1278         g_free(cmp_buf);
1279     }
1280 
1281     block_acct_done(blk_get_stats(ctx->blk), &ctx->acct);
1282 
1283     if (ctx->qflag) {
1284         goto out;
1285     }
1286 
1287     if (ctx->vflag) {
1288         dump_buffer(ctx->buf, ctx->offset, ctx->qiov.size);
1289     }
1290 
1291     /* Finally, report back -- -C gives a parsable format */
1292     t2 = tsub(t2, ctx->t1);
1293     print_report("read", &t2, ctx->offset, ctx->qiov.size,
1294                  ctx->qiov.size, 1, ctx->Cflag);
1295 out:
1296     qemu_io_free(ctx->buf);
1297     qemu_iovec_destroy(&ctx->qiov);
1298     g_free(ctx);
1299 }
1300 
1301 static void aio_read_help(void)
1302 {
1303     printf(
1304 "\n"
1305 " asynchronously reads a range of bytes from the given offset\n"
1306 "\n"
1307 " Example:\n"
1308 " 'aio_read -v 512 1k 1k ' - dumps 2 kilobytes read from 512 bytes into the file\n"
1309 "\n"
1310 " Reads a segment of the currently open file, optionally dumping it to the\n"
1311 " standard output stream (with -v option) for subsequent inspection.\n"
1312 " The read is performed asynchronously and the aio_flush command must be\n"
1313 " used to ensure all outstanding aio requests have been completed.\n"
1314 " -C, -- report statistics in a machine parsable format\n"
1315 " -P, -- use a pattern to verify read data\n"
1316 " -i, -- treat request as invalid, for exercising stats\n"
1317 " -v, -- dump buffer to standard output\n"
1318 " -q, -- quiet mode, do not show I/O statistics\n"
1319 "\n");
1320 }
1321 
1322 static int aio_read_f(BlockBackend *blk, int argc, char **argv);
1323 
1324 static const cmdinfo_t aio_read_cmd = {
1325     .name       = "aio_read",
1326     .cfunc      = aio_read_f,
1327     .argmin     = 2,
1328     .argmax     = -1,
1329     .args       = "[-Ciqv] [-P pattern] off len [len..]",
1330     .oneline    = "asynchronously reads a number of bytes",
1331     .help       = aio_read_help,
1332 };
1333 
1334 static int aio_read_f(BlockBackend *blk, int argc, char **argv)
1335 {
1336     int nr_iov, c;
1337     struct aio_ctx *ctx = g_new0(struct aio_ctx, 1);
1338 
1339     ctx->blk = blk;
1340     while ((c = getopt(argc, argv, "CP:iqv")) != -1) {
1341         switch (c) {
1342         case 'C':
1343             ctx->Cflag = true;
1344             break;
1345         case 'P':
1346             ctx->Pflag = true;
1347             ctx->pattern = parse_pattern(optarg);
1348             if (ctx->pattern < 0) {
1349                 g_free(ctx);
1350                 return 0;
1351             }
1352             break;
1353         case 'i':
1354             printf("injecting invalid read request\n");
1355             block_acct_invalid(blk_get_stats(blk), BLOCK_ACCT_READ);
1356             g_free(ctx);
1357             return 0;
1358         case 'q':
1359             ctx->qflag = true;
1360             break;
1361         case 'v':
1362             ctx->vflag = true;
1363             break;
1364         default:
1365             g_free(ctx);
1366             return qemuio_command_usage(&aio_read_cmd);
1367         }
1368     }
1369 
1370     if (optind > argc - 2) {
1371         g_free(ctx);
1372         return qemuio_command_usage(&aio_read_cmd);
1373     }
1374 
1375     ctx->offset = cvtnum(argv[optind]);
1376     if (ctx->offset < 0) {
1377         print_cvtnum_err(ctx->offset, argv[optind]);
1378         g_free(ctx);
1379         return 0;
1380     }
1381     optind++;
1382 
1383     nr_iov = argc - optind;
1384     ctx->buf = create_iovec(blk, &ctx->qiov, &argv[optind], nr_iov, 0xab);
1385     if (ctx->buf == NULL) {
1386         block_acct_invalid(blk_get_stats(blk), BLOCK_ACCT_READ);
1387         g_free(ctx);
1388         return 0;
1389     }
1390 
1391     gettimeofday(&ctx->t1, NULL);
1392     block_acct_start(blk_get_stats(blk), &ctx->acct, ctx->qiov.size,
1393                      BLOCK_ACCT_READ);
1394     blk_aio_preadv(blk, ctx->offset, &ctx->qiov, 0, aio_read_done, ctx);
1395     return 0;
1396 }
1397 
1398 static void aio_write_help(void)
1399 {
1400     printf(
1401 "\n"
1402 " asynchronously writes a range of bytes from the given offset source\n"
1403 " from multiple buffers\n"
1404 "\n"
1405 " Example:\n"
1406 " 'aio_write 512 1k 1k' - writes 2 kilobytes at 512 bytes into the open file\n"
1407 "\n"
1408 " Writes into a segment of the currently open file, using a buffer\n"
1409 " filled with a set pattern (0xcdcdcdcd).\n"
1410 " The write is performed asynchronously and the aio_flush command must be\n"
1411 " used to ensure all outstanding aio requests have been completed.\n"
1412 " -P, -- use different pattern to fill file\n"
1413 " -C, -- report statistics in a machine parsable format\n"
1414 " -f, -- use Force Unit Access semantics\n"
1415 " -i, -- treat request as invalid, for exercising stats\n"
1416 " -q, -- quiet mode, do not show I/O statistics\n"
1417 " -u, -- with -z, allow unmapping\n"
1418 " -z, -- write zeroes using blk_aio_pwrite_zeroes\n"
1419 "\n");
1420 }
1421 
1422 static int aio_write_f(BlockBackend *blk, int argc, char **argv);
1423 
1424 static const cmdinfo_t aio_write_cmd = {
1425     .name       = "aio_write",
1426     .cfunc      = aio_write_f,
1427     .perm       = BLK_PERM_WRITE,
1428     .argmin     = 2,
1429     .argmax     = -1,
1430     .args       = "[-Cfiquz] [-P pattern] off len [len..]",
1431     .oneline    = "asynchronously writes a number of bytes",
1432     .help       = aio_write_help,
1433 };
1434 
1435 static int aio_write_f(BlockBackend *blk, int argc, char **argv)
1436 {
1437     int nr_iov, c;
1438     int pattern = 0xcd;
1439     struct aio_ctx *ctx = g_new0(struct aio_ctx, 1);
1440     int flags = 0;
1441 
1442     ctx->blk = blk;
1443     while ((c = getopt(argc, argv, "CfiqP:uz")) != -1) {
1444         switch (c) {
1445         case 'C':
1446             ctx->Cflag = true;
1447             break;
1448         case 'f':
1449             flags |= BDRV_REQ_FUA;
1450             break;
1451         case 'q':
1452             ctx->qflag = true;
1453             break;
1454         case 'u':
1455             flags |= BDRV_REQ_MAY_UNMAP;
1456             break;
1457         case 'P':
1458             pattern = parse_pattern(optarg);
1459             if (pattern < 0) {
1460                 g_free(ctx);
1461                 return 0;
1462             }
1463             break;
1464         case 'i':
1465             printf("injecting invalid write request\n");
1466             block_acct_invalid(blk_get_stats(blk), BLOCK_ACCT_WRITE);
1467             g_free(ctx);
1468             return 0;
1469         case 'z':
1470             ctx->zflag = true;
1471             break;
1472         default:
1473             g_free(ctx);
1474             return qemuio_command_usage(&aio_write_cmd);
1475         }
1476     }
1477 
1478     if (optind > argc - 2) {
1479         g_free(ctx);
1480         return qemuio_command_usage(&aio_write_cmd);
1481     }
1482 
1483     if (ctx->zflag && optind != argc - 2) {
1484         printf("-z supports only a single length parameter\n");
1485         g_free(ctx);
1486         return 0;
1487     }
1488 
1489     if ((flags & BDRV_REQ_MAY_UNMAP) && !ctx->zflag) {
1490         printf("-u requires -z to be specified\n");
1491         g_free(ctx);
1492         return 0;
1493     }
1494 
1495     if (ctx->zflag && ctx->Pflag) {
1496         printf("-z and -P cannot be specified at the same time\n");
1497         g_free(ctx);
1498         return 0;
1499     }
1500 
1501     ctx->offset = cvtnum(argv[optind]);
1502     if (ctx->offset < 0) {
1503         print_cvtnum_err(ctx->offset, argv[optind]);
1504         g_free(ctx);
1505         return 0;
1506     }
1507     optind++;
1508 
1509     if (ctx->zflag) {
1510         int64_t count = cvtnum(argv[optind]);
1511         if (count < 0) {
1512             print_cvtnum_err(count, argv[optind]);
1513             g_free(ctx);
1514             return 0;
1515         }
1516 
1517         ctx->qiov.size = count;
1518         blk_aio_pwrite_zeroes(blk, ctx->offset, count, flags, aio_write_done,
1519                               ctx);
1520     } else {
1521         nr_iov = argc - optind;
1522         ctx->buf = create_iovec(blk, &ctx->qiov, &argv[optind], nr_iov,
1523                                 pattern);
1524         if (ctx->buf == NULL) {
1525             block_acct_invalid(blk_get_stats(blk), BLOCK_ACCT_WRITE);
1526             g_free(ctx);
1527             return 0;
1528         }
1529 
1530         gettimeofday(&ctx->t1, NULL);
1531         block_acct_start(blk_get_stats(blk), &ctx->acct, ctx->qiov.size,
1532                          BLOCK_ACCT_WRITE);
1533 
1534         blk_aio_pwritev(blk, ctx->offset, &ctx->qiov, flags, aio_write_done,
1535                         ctx);
1536     }
1537     return 0;
1538 }
1539 
1540 static int aio_flush_f(BlockBackend *blk, int argc, char **argv)
1541 {
1542     BlockAcctCookie cookie;
1543     block_acct_start(blk_get_stats(blk), &cookie, 0, BLOCK_ACCT_FLUSH);
1544     blk_drain_all();
1545     block_acct_done(blk_get_stats(blk), &cookie);
1546     return 0;
1547 }
1548 
1549 static const cmdinfo_t aio_flush_cmd = {
1550     .name       = "aio_flush",
1551     .cfunc      = aio_flush_f,
1552     .oneline    = "completes all outstanding aio requests"
1553 };
1554 
1555 static int flush_f(BlockBackend *blk, int argc, char **argv)
1556 {
1557     blk_flush(blk);
1558     return 0;
1559 }
1560 
1561 static const cmdinfo_t flush_cmd = {
1562     .name       = "flush",
1563     .altname    = "f",
1564     .cfunc      = flush_f,
1565     .oneline    = "flush all in-core file state to disk",
1566 };
1567 
1568 static int truncate_f(BlockBackend *blk, int argc, char **argv)
1569 {
1570     Error *local_err = NULL;
1571     int64_t offset;
1572     int ret;
1573 
1574     offset = cvtnum(argv[1]);
1575     if (offset < 0) {
1576         print_cvtnum_err(offset, argv[1]);
1577         return 0;
1578     }
1579 
1580     ret = blk_truncate(blk, offset, PREALLOC_MODE_OFF, &local_err);
1581     if (ret < 0) {
1582         error_report_err(local_err);
1583         return 0;
1584     }
1585 
1586     return 0;
1587 }
1588 
1589 static const cmdinfo_t truncate_cmd = {
1590     .name       = "truncate",
1591     .altname    = "t",
1592     .cfunc      = truncate_f,
1593     .perm       = BLK_PERM_WRITE | BLK_PERM_RESIZE,
1594     .argmin     = 1,
1595     .argmax     = 1,
1596     .args       = "off",
1597     .oneline    = "truncates the current file at the given offset",
1598 };
1599 
1600 static int length_f(BlockBackend *blk, int argc, char **argv)
1601 {
1602     int64_t size;
1603     char s1[64];
1604 
1605     size = blk_getlength(blk);
1606     if (size < 0) {
1607         printf("getlength: %s\n", strerror(-size));
1608         return 0;
1609     }
1610 
1611     cvtstr(size, s1, sizeof(s1));
1612     printf("%s\n", s1);
1613     return 0;
1614 }
1615 
1616 
1617 static const cmdinfo_t length_cmd = {
1618     .name   = "length",
1619     .altname    = "l",
1620     .cfunc      = length_f,
1621     .oneline    = "gets the length of the current file",
1622 };
1623 
1624 
1625 static int info_f(BlockBackend *blk, int argc, char **argv)
1626 {
1627     BlockDriverState *bs = blk_bs(blk);
1628     BlockDriverInfo bdi;
1629     ImageInfoSpecific *spec_info;
1630     char s1[64], s2[64];
1631     int ret;
1632 
1633     if (bs->drv && bs->drv->format_name) {
1634         printf("format name: %s\n", bs->drv->format_name);
1635     }
1636     if (bs->drv && bs->drv->protocol_name) {
1637         printf("format name: %s\n", bs->drv->protocol_name);
1638     }
1639 
1640     ret = bdrv_get_info(bs, &bdi);
1641     if (ret) {
1642         return 0;
1643     }
1644 
1645     cvtstr(bdi.cluster_size, s1, sizeof(s1));
1646     cvtstr(bdi.vm_state_offset, s2, sizeof(s2));
1647 
1648     printf("cluster size: %s\n", s1);
1649     printf("vm state offset: %s\n", s2);
1650 
1651     spec_info = bdrv_get_specific_info(bs);
1652     if (spec_info) {
1653         printf("Format specific information:\n");
1654         bdrv_image_info_specific_dump(fprintf, stdout, spec_info);
1655         qapi_free_ImageInfoSpecific(spec_info);
1656     }
1657 
1658     return 0;
1659 }
1660 
1661 
1662 
1663 static const cmdinfo_t info_cmd = {
1664     .name       = "info",
1665     .altname    = "i",
1666     .cfunc      = info_f,
1667     .oneline    = "prints information about the current file",
1668 };
1669 
1670 static void discard_help(void)
1671 {
1672     printf(
1673 "\n"
1674 " discards a range of bytes from the given offset\n"
1675 "\n"
1676 " Example:\n"
1677 " 'discard 512 1k' - discards 1 kilobyte from 512 bytes into the file\n"
1678 "\n"
1679 " Discards a segment of the currently open file.\n"
1680 " -C, -- report statistics in a machine parsable format\n"
1681 " -q, -- quiet mode, do not show I/O statistics\n"
1682 "\n");
1683 }
1684 
1685 static int discard_f(BlockBackend *blk, int argc, char **argv);
1686 
1687 static const cmdinfo_t discard_cmd = {
1688     .name       = "discard",
1689     .altname    = "d",
1690     .cfunc      = discard_f,
1691     .perm       = BLK_PERM_WRITE,
1692     .argmin     = 2,
1693     .argmax     = -1,
1694     .args       = "[-Cq] off len",
1695     .oneline    = "discards a number of bytes at a specified offset",
1696     .help       = discard_help,
1697 };
1698 
1699 static int discard_f(BlockBackend *blk, int argc, char **argv)
1700 {
1701     struct timeval t1, t2;
1702     bool Cflag = false, qflag = false;
1703     int c, ret;
1704     int64_t offset, bytes;
1705 
1706     while ((c = getopt(argc, argv, "Cq")) != -1) {
1707         switch (c) {
1708         case 'C':
1709             Cflag = true;
1710             break;
1711         case 'q':
1712             qflag = true;
1713             break;
1714         default:
1715             return qemuio_command_usage(&discard_cmd);
1716         }
1717     }
1718 
1719     if (optind != argc - 2) {
1720         return qemuio_command_usage(&discard_cmd);
1721     }
1722 
1723     offset = cvtnum(argv[optind]);
1724     if (offset < 0) {
1725         print_cvtnum_err(offset, argv[optind]);
1726         return 0;
1727     }
1728 
1729     optind++;
1730     bytes = cvtnum(argv[optind]);
1731     if (bytes < 0) {
1732         print_cvtnum_err(bytes, argv[optind]);
1733         return 0;
1734     } else if (bytes >> BDRV_SECTOR_BITS > BDRV_REQUEST_MAX_SECTORS) {
1735         printf("length cannot exceed %"PRIu64", given %s\n",
1736                (uint64_t)BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS,
1737                argv[optind]);
1738         return 0;
1739     }
1740 
1741     gettimeofday(&t1, NULL);
1742     ret = blk_pdiscard(blk, offset, bytes);
1743     gettimeofday(&t2, NULL);
1744 
1745     if (ret < 0) {
1746         printf("discard failed: %s\n", strerror(-ret));
1747         goto out;
1748     }
1749 
1750     /* Finally, report back -- -C gives a parsable format */
1751     if (!qflag) {
1752         t2 = tsub(t2, t1);
1753         print_report("discard", &t2, offset, bytes, bytes, 1, Cflag);
1754     }
1755 
1756 out:
1757     return 0;
1758 }
1759 
1760 static int alloc_f(BlockBackend *blk, int argc, char **argv)
1761 {
1762     BlockDriverState *bs = blk_bs(blk);
1763     int64_t offset, start, remaining, count;
1764     char s1[64];
1765     int ret;
1766     int64_t num, sum_alloc;
1767 
1768     start = offset = cvtnum(argv[1]);
1769     if (offset < 0) {
1770         print_cvtnum_err(offset, argv[1]);
1771         return 0;
1772     } else if (!QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)) {
1773         printf("%" PRId64 " is not a sector-aligned value for 'offset'\n",
1774                offset);
1775         return 0;
1776     }
1777 
1778     if (argc == 3) {
1779         count = cvtnum(argv[2]);
1780         if (count < 0) {
1781             print_cvtnum_err(count, argv[2]);
1782             return 0;
1783         } else if (count > INT_MAX * BDRV_SECTOR_SIZE) {
1784             printf("length argument cannot exceed %llu, given %s\n",
1785                    INT_MAX * BDRV_SECTOR_SIZE, argv[2]);
1786             return 0;
1787         }
1788     } else {
1789         count = BDRV_SECTOR_SIZE;
1790     }
1791     if (!QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)) {
1792         printf("%" PRId64 " is not a sector-aligned value for 'count'\n",
1793                count);
1794         return 0;
1795     }
1796 
1797     remaining = count;
1798     sum_alloc = 0;
1799     while (remaining) {
1800         ret = bdrv_is_allocated(bs, offset, remaining, &num);
1801         if (ret < 0) {
1802             printf("is_allocated failed: %s\n", strerror(-ret));
1803             return 0;
1804         }
1805         offset += num;
1806         remaining -= num;
1807         if (ret) {
1808             sum_alloc += num;
1809         }
1810         if (num == 0) {
1811             count -= remaining;
1812             remaining = 0;
1813         }
1814     }
1815 
1816     cvtstr(start, s1, sizeof(s1));
1817 
1818     printf("%"PRId64"/%"PRId64" bytes allocated at offset %s\n",
1819            sum_alloc, count, s1);
1820     return 0;
1821 }
1822 
1823 static const cmdinfo_t alloc_cmd = {
1824     .name       = "alloc",
1825     .altname    = "a",
1826     .argmin     = 1,
1827     .argmax     = 2,
1828     .cfunc      = alloc_f,
1829     .args       = "offset [count]",
1830     .oneline    = "checks if offset is allocated in the file",
1831 };
1832 
1833 
1834 static int map_is_allocated(BlockDriverState *bs, int64_t offset,
1835                             int64_t bytes, int64_t *pnum)
1836 {
1837     int64_t num;
1838     int num_checked;
1839     int ret, firstret;
1840 
1841     num_checked = MIN(bytes, BDRV_REQUEST_MAX_BYTES);
1842     ret = bdrv_is_allocated(bs, offset, num_checked, &num);
1843     if (ret < 0) {
1844         return ret;
1845     }
1846 
1847     firstret = ret;
1848     *pnum = num;
1849 
1850     while (bytes > 0 && ret == firstret) {
1851         offset += num;
1852         bytes -= num;
1853 
1854         num_checked = MIN(bytes, BDRV_REQUEST_MAX_BYTES);
1855         ret = bdrv_is_allocated(bs, offset, num_checked, &num);
1856         if (ret == firstret && num) {
1857             *pnum += num;
1858         } else {
1859             break;
1860         }
1861     }
1862 
1863     return firstret;
1864 }
1865 
1866 static int map_f(BlockBackend *blk, int argc, char **argv)
1867 {
1868     int64_t offset, bytes;
1869     char s1[64], s2[64];
1870     int64_t num;
1871     int ret;
1872     const char *retstr;
1873 
1874     offset = 0;
1875     bytes = blk_getlength(blk);
1876     if (bytes < 0) {
1877         error_report("Failed to query image length: %s", strerror(-bytes));
1878         return 0;
1879     }
1880 
1881     while (bytes) {
1882         ret = map_is_allocated(blk_bs(blk), offset, bytes, &num);
1883         if (ret < 0) {
1884             error_report("Failed to get allocation status: %s", strerror(-ret));
1885             return 0;
1886         } else if (!num) {
1887             error_report("Unexpected end of image");
1888             return 0;
1889         }
1890 
1891         retstr = ret ? "    allocated" : "not allocated";
1892         cvtstr(num, s1, sizeof(s1));
1893         cvtstr(offset, s2, sizeof(s2));
1894         printf("%s (0x%" PRIx64 ") bytes %s at offset %s (0x%" PRIx64 ")\n",
1895                s1, num, retstr, s2, offset);
1896 
1897         offset += num;
1898         bytes -= num;
1899     }
1900 
1901     return 0;
1902 }
1903 
1904 static const cmdinfo_t map_cmd = {
1905        .name           = "map",
1906        .argmin         = 0,
1907        .argmax         = 0,
1908        .cfunc          = map_f,
1909        .args           = "",
1910        .oneline        = "prints the allocated areas of a file",
1911 };
1912 
1913 static void reopen_help(void)
1914 {
1915     printf(
1916 "\n"
1917 " Changes the open options of an already opened image\n"
1918 "\n"
1919 " Example:\n"
1920 " 'reopen -o lazy-refcounts=on' - activates lazy refcount writeback on a qcow2 image\n"
1921 "\n"
1922 " -r, -- Reopen the image read-only\n"
1923 " -w, -- Reopen the image read-write\n"
1924 " -c, -- Change the cache mode to the given value\n"
1925 " -o, -- Changes block driver options (cf. 'open' command)\n"
1926 "\n");
1927 }
1928 
1929 static int reopen_f(BlockBackend *blk, int argc, char **argv);
1930 
1931 static QemuOptsList reopen_opts = {
1932     .name = "reopen",
1933     .merge_lists = true,
1934     .head = QTAILQ_HEAD_INITIALIZER(reopen_opts.head),
1935     .desc = {
1936         /* no elements => accept any params */
1937         { /* end of list */ }
1938     },
1939 };
1940 
1941 static const cmdinfo_t reopen_cmd = {
1942        .name           = "reopen",
1943        .argmin         = 0,
1944        .argmax         = -1,
1945        .cfunc          = reopen_f,
1946        .args           = "[(-r|-w)] [-c cache] [-o options]",
1947        .oneline        = "reopens an image with new options",
1948        .help           = reopen_help,
1949 };
1950 
1951 static int reopen_f(BlockBackend *blk, int argc, char **argv)
1952 {
1953     BlockDriverState *bs = blk_bs(blk);
1954     QemuOpts *qopts;
1955     QDict *opts;
1956     int c;
1957     int flags = bs->open_flags;
1958     bool writethrough = !blk_enable_write_cache(blk);
1959     bool has_rw_option = false;
1960 
1961     BlockReopenQueue *brq;
1962     Error *local_err = NULL;
1963 
1964     while ((c = getopt(argc, argv, "c:o:rw")) != -1) {
1965         switch (c) {
1966         case 'c':
1967             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) < 0) {
1968                 error_report("Invalid cache option: %s", optarg);
1969                 return 0;
1970             }
1971             break;
1972         case 'o':
1973             if (!qemu_opts_parse_noisily(&reopen_opts, optarg, 0)) {
1974                 qemu_opts_reset(&reopen_opts);
1975                 return 0;
1976             }
1977             break;
1978         case 'r':
1979             if (has_rw_option) {
1980                 error_report("Only one -r/-w option may be given");
1981                 return 0;
1982             }
1983             flags &= ~BDRV_O_RDWR;
1984             has_rw_option = true;
1985             break;
1986         case 'w':
1987             if (has_rw_option) {
1988                 error_report("Only one -r/-w option may be given");
1989                 return 0;
1990             }
1991             flags |= BDRV_O_RDWR;
1992             has_rw_option = true;
1993             break;
1994         default:
1995             qemu_opts_reset(&reopen_opts);
1996             return qemuio_command_usage(&reopen_cmd);
1997         }
1998     }
1999 
2000     if (optind != argc) {
2001         qemu_opts_reset(&reopen_opts);
2002         return qemuio_command_usage(&reopen_cmd);
2003     }
2004 
2005     if (writethrough != blk_enable_write_cache(blk) &&
2006         blk_get_attached_dev(blk))
2007     {
2008         error_report("Cannot change cache.writeback: Device attached");
2009         qemu_opts_reset(&reopen_opts);
2010         return 0;
2011     }
2012 
2013     if (!(flags & BDRV_O_RDWR)) {
2014         uint64_t orig_perm, orig_shared_perm;
2015 
2016         bdrv_drain(bs);
2017 
2018         blk_get_perm(blk, &orig_perm, &orig_shared_perm);
2019         blk_set_perm(blk,
2020                      orig_perm & ~(BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED),
2021                      orig_shared_perm,
2022                      &error_abort);
2023     }
2024 
2025     qopts = qemu_opts_find(&reopen_opts, NULL);
2026     opts = qopts ? qemu_opts_to_qdict(qopts, NULL) : NULL;
2027     qemu_opts_reset(&reopen_opts);
2028 
2029     brq = bdrv_reopen_queue(NULL, bs, opts, flags);
2030     bdrv_reopen_multiple(bdrv_get_aio_context(bs), brq, &local_err);
2031     if (local_err) {
2032         error_report_err(local_err);
2033     } else {
2034         blk_set_enable_write_cache(blk, !writethrough);
2035     }
2036 
2037     return 0;
2038 }
2039 
2040 static int break_f(BlockBackend *blk, int argc, char **argv)
2041 {
2042     int ret;
2043 
2044     ret = bdrv_debug_breakpoint(blk_bs(blk), argv[1], argv[2]);
2045     if (ret < 0) {
2046         printf("Could not set breakpoint: %s\n", strerror(-ret));
2047     }
2048 
2049     return 0;
2050 }
2051 
2052 static int remove_break_f(BlockBackend *blk, int argc, char **argv)
2053 {
2054     int ret;
2055 
2056     ret = bdrv_debug_remove_breakpoint(blk_bs(blk), argv[1]);
2057     if (ret < 0) {
2058         printf("Could not remove breakpoint %s: %s\n", argv[1], strerror(-ret));
2059     }
2060 
2061     return 0;
2062 }
2063 
2064 static const cmdinfo_t break_cmd = {
2065        .name           = "break",
2066        .argmin         = 2,
2067        .argmax         = 2,
2068        .cfunc          = break_f,
2069        .args           = "event tag",
2070        .oneline        = "sets a breakpoint on event and tags the stopped "
2071                          "request as tag",
2072 };
2073 
2074 static const cmdinfo_t remove_break_cmd = {
2075        .name           = "remove_break",
2076        .argmin         = 1,
2077        .argmax         = 1,
2078        .cfunc          = remove_break_f,
2079        .args           = "tag",
2080        .oneline        = "remove a breakpoint by tag",
2081 };
2082 
2083 static int resume_f(BlockBackend *blk, int argc, char **argv)
2084 {
2085     int ret;
2086 
2087     ret = bdrv_debug_resume(blk_bs(blk), argv[1]);
2088     if (ret < 0) {
2089         printf("Could not resume request: %s\n", strerror(-ret));
2090     }
2091 
2092     return 0;
2093 }
2094 
2095 static const cmdinfo_t resume_cmd = {
2096        .name           = "resume",
2097        .argmin         = 1,
2098        .argmax         = 1,
2099        .cfunc          = resume_f,
2100        .args           = "tag",
2101        .oneline        = "resumes the request tagged as tag",
2102 };
2103 
2104 static int wait_break_f(BlockBackend *blk, int argc, char **argv)
2105 {
2106     while (!bdrv_debug_is_suspended(blk_bs(blk), argv[1])) {
2107         aio_poll(blk_get_aio_context(blk), true);
2108     }
2109 
2110     return 0;
2111 }
2112 
2113 static const cmdinfo_t wait_break_cmd = {
2114        .name           = "wait_break",
2115        .argmin         = 1,
2116        .argmax         = 1,
2117        .cfunc          = wait_break_f,
2118        .args           = "tag",
2119        .oneline        = "waits for the suspension of a request",
2120 };
2121 
2122 static int abort_f(BlockBackend *blk, int argc, char **argv)
2123 {
2124     abort();
2125 }
2126 
2127 static const cmdinfo_t abort_cmd = {
2128        .name           = "abort",
2129        .cfunc          = abort_f,
2130        .flags          = CMD_NOFILE_OK,
2131        .oneline        = "simulate a program crash using abort(3)",
2132 };
2133 
2134 static void sigraise_help(void)
2135 {
2136     printf(
2137 "\n"
2138 " raises the given signal\n"
2139 "\n"
2140 " Example:\n"
2141 " 'sigraise %i' - raises SIGTERM\n"
2142 "\n"
2143 " Invokes raise(signal), where \"signal\" is the mandatory integer argument\n"
2144 " given to sigraise.\n"
2145 "\n", SIGTERM);
2146 }
2147 
2148 static int sigraise_f(BlockBackend *blk, int argc, char **argv);
2149 
2150 static const cmdinfo_t sigraise_cmd = {
2151     .name       = "sigraise",
2152     .cfunc      = sigraise_f,
2153     .argmin     = 1,
2154     .argmax     = 1,
2155     .flags      = CMD_NOFILE_OK,
2156     .args       = "signal",
2157     .oneline    = "raises a signal",
2158     .help       = sigraise_help,
2159 };
2160 
2161 static int sigraise_f(BlockBackend *blk, int argc, char **argv)
2162 {
2163     int64_t sig = cvtnum(argv[1]);
2164     if (sig < 0) {
2165         print_cvtnum_err(sig, argv[1]);
2166         return 0;
2167     } else if (sig > NSIG) {
2168         printf("signal argument '%s' is too large to be a valid signal\n",
2169                argv[1]);
2170         return 0;
2171     }
2172 
2173     /* Using raise() to kill this process does not necessarily flush all open
2174      * streams. At least stdout and stderr (although the latter should be
2175      * non-buffered anyway) should be flushed, though. */
2176     fflush(stdout);
2177     fflush(stderr);
2178 
2179     raise(sig);
2180     return 0;
2181 }
2182 
2183 static void sleep_cb(void *opaque)
2184 {
2185     bool *expired = opaque;
2186     *expired = true;
2187 }
2188 
2189 static int sleep_f(BlockBackend *blk, int argc, char **argv)
2190 {
2191     char *endptr;
2192     long ms;
2193     struct QEMUTimer *timer;
2194     bool expired = false;
2195 
2196     ms = strtol(argv[1], &endptr, 0);
2197     if (ms < 0 || *endptr != '\0') {
2198         printf("%s is not a valid number\n", argv[1]);
2199         return 0;
2200     }
2201 
2202     timer = timer_new_ns(QEMU_CLOCK_HOST, sleep_cb, &expired);
2203     timer_mod(timer, qemu_clock_get_ns(QEMU_CLOCK_HOST) + SCALE_MS * ms);
2204 
2205     while (!expired) {
2206         main_loop_wait(false);
2207     }
2208 
2209     timer_free(timer);
2210 
2211     return 0;
2212 }
2213 
2214 static const cmdinfo_t sleep_cmd = {
2215        .name           = "sleep",
2216        .argmin         = 1,
2217        .argmax         = 1,
2218        .cfunc          = sleep_f,
2219        .flags          = CMD_NOFILE_OK,
2220        .oneline        = "waits for the given value in milliseconds",
2221 };
2222 
2223 static void help_oneline(const char *cmd, const cmdinfo_t *ct)
2224 {
2225     if (cmd) {
2226         printf("%s ", cmd);
2227     } else {
2228         printf("%s ", ct->name);
2229         if (ct->altname) {
2230             printf("(or %s) ", ct->altname);
2231         }
2232     }
2233 
2234     if (ct->args) {
2235         printf("%s ", ct->args);
2236     }
2237     printf("-- %s\n", ct->oneline);
2238 }
2239 
2240 static void help_onecmd(const char *cmd, const cmdinfo_t *ct)
2241 {
2242     help_oneline(cmd, ct);
2243     if (ct->help) {
2244         ct->help();
2245     }
2246 }
2247 
2248 static void help_all(void)
2249 {
2250     const cmdinfo_t *ct;
2251 
2252     for (ct = cmdtab; ct < &cmdtab[ncmds]; ct++) {
2253         help_oneline(ct->name, ct);
2254     }
2255     printf("\nUse 'help commandname' for extended help.\n");
2256 }
2257 
2258 static int help_f(BlockBackend *blk, int argc, char **argv)
2259 {
2260     const cmdinfo_t *ct;
2261 
2262     if (argc == 1) {
2263         help_all();
2264         return 0;
2265     }
2266 
2267     ct = find_command(argv[1]);
2268     if (ct == NULL) {
2269         printf("command %s not found\n", argv[1]);
2270         return 0;
2271     }
2272 
2273     help_onecmd(argv[1], ct);
2274     return 0;
2275 }
2276 
2277 static const cmdinfo_t help_cmd = {
2278     .name       = "help",
2279     .altname    = "?",
2280     .cfunc      = help_f,
2281     .argmin     = 0,
2282     .argmax     = 1,
2283     .flags      = CMD_FLAG_GLOBAL,
2284     .args       = "[command]",
2285     .oneline    = "help for one or all commands",
2286 };
2287 
2288 bool qemuio_command(BlockBackend *blk, const char *cmd)
2289 {
2290     AioContext *ctx;
2291     char *input;
2292     const cmdinfo_t *ct;
2293     char **v;
2294     int c;
2295     bool done = false;
2296 
2297     input = g_strdup(cmd);
2298     v = breakline(input, &c);
2299     if (c) {
2300         ct = find_command(v[0]);
2301         if (ct) {
2302             ctx = blk ? blk_get_aio_context(blk) : qemu_get_aio_context();
2303             aio_context_acquire(ctx);
2304             done = command(blk, ct, c, v);
2305             aio_context_release(ctx);
2306         } else {
2307             fprintf(stderr, "command \"%s\" not found\n", v[0]);
2308         }
2309     }
2310     g_free(input);
2311     g_free(v);
2312 
2313     return done;
2314 }
2315 
2316 static void __attribute((constructor)) init_qemuio_commands(void)
2317 {
2318     /* initialize commands */
2319     qemuio_add_command(&help_cmd);
2320     qemuio_add_command(&read_cmd);
2321     qemuio_add_command(&readv_cmd);
2322     qemuio_add_command(&write_cmd);
2323     qemuio_add_command(&writev_cmd);
2324     qemuio_add_command(&aio_read_cmd);
2325     qemuio_add_command(&aio_write_cmd);
2326     qemuio_add_command(&aio_flush_cmd);
2327     qemuio_add_command(&flush_cmd);
2328     qemuio_add_command(&truncate_cmd);
2329     qemuio_add_command(&length_cmd);
2330     qemuio_add_command(&info_cmd);
2331     qemuio_add_command(&discard_cmd);
2332     qemuio_add_command(&alloc_cmd);
2333     qemuio_add_command(&map_cmd);
2334     qemuio_add_command(&reopen_cmd);
2335     qemuio_add_command(&break_cmd);
2336     qemuio_add_command(&remove_break_cmd);
2337     qemuio_add_command(&resume_cmd);
2338     qemuio_add_command(&wait_break_cmd);
2339     qemuio_add_command(&abort_cmd);
2340     qemuio_add_command(&sleep_cmd);
2341     qemuio_add_command(&sigraise_cmd);
2342 }
2343