qemu-option.c

   1 /*
   2  * Commandline option parsing functions
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  * Copyright (c) 2009 Kevin Wolf <kwolf@redhat.com>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include <stdio.h>
  27 #include <string.h>
  28
  29 #include "qemu-common.h"
  30 #include "qemu-option.h"
  31
  32 /*
  33  * Extracts the name of an option from the parameter string (p points at the
  34  * first byte of the option name)
  35  *
  36  * The option name is delimited by delim (usually , or =) or the string end
  37  * and is copied into buf. If the option name is longer than buf_size, it is
  38  * truncated. buf is always zero terminated.
  39  *
  40  * The return value is the position of the delimiter/zero byte after the option
  41  * name in p.
  42  */
  43 const char *get_opt_name(char *buf, int buf_size, const char *p, char delim)
  44 {
  45     char *q;
  46
  47     q = buf;
  48     while (*p != '\0' && *p != delim) {
  49         if (q && (q - buf) < buf_size - 1)
  50             *q++ = *p;
  51         p++;
  52     }
  53     if (q)
  54         *q = '\0';
  55
  56     return p;
  57 }
  58
  59 /*
  60  * Extracts the value of an option from the parameter string p (p points at the
  61  * first byte of the option value)
  62  *
  63  * This function is comparable to get_opt_name with the difference that the
  64  * delimiter is fixed to be comma which starts a new option. To specify an
  65  * option value that contains commas, double each comma.
  66  */
  67 const char *get_opt_value(char *buf, int buf_size, const char *p)
  68 {
  69     char *q;
  70
  71     q = buf;
  72     while (*p != '\0') {
  73         if (*p == ',') {
  74             if (*(p + 1) != ',')
  75                 break;
  76             p++;
  77         }
  78         if (q && (q - buf) < buf_size - 1)
  79             *q++ = *p;
  80         p++;
  81     }
  82     if (q)
  83         *q = '\0';
  84
  85     return p;
  86 }
  87
  88 int get_next_param_value(char *buf, int buf_size,
  89                          const char *tag, const char **pstr)
  90 {
  91     const char *p;
  92     char option[128];
  93
  94     p = *pstr;
  95     for(;;) {
  96         p = get_opt_name(option, sizeof(option), p, '=');
  97         if (*p != '=')
  98             break;
  99         p++;
 100         if (!strcmp(tag, option)) {
 101             *pstr = get_opt_value(buf, buf_size, p);
 102             if (**pstr == ',') {
 103                 (*pstr)++;
 104             }
 105             return strlen(buf);
 106         } else {
 107             p = get_opt_value(NULL, 0, p);
 108         }
 109         if (*p != ',')
 110             break;
 111         p++;
 112     }
 113     return 0;
 114 }
 115
 116 int get_param_value(char *buf, int buf_size,
 117                     const char *tag, const char *str)
 118 {
 119     return get_next_param_value(buf, buf_size, tag, &str);
 120 }
 121
 122 int check_params(char *buf, int buf_size,
 123                  const char * const *params, const char *str)
 124 {
 125     const char *p;
 126     int i;
 127
 128     p = str;
 129     while (*p != '\0') {
 130         p = get_opt_name(buf, buf_size, p, '=');
 131         if (*p != '=') {
 132             return -1;
 133         }
 134         p++;
 135         for (i = 0; params[i] != NULL; i++) {
 136             if (!strcmp(params[i], buf)) {
 137                 break;
 138             }
 139         }
 140         if (params[i] == NULL) {
 141             return -1;
 142         }
 143         p = get_opt_value(NULL, 0, p);
 144         if (*p != ',') {
 145             break;
 146         }
 147         p++;
 148     }
 149     return 0;
 150 }
 151
 152 /*
 153  * Searches an option list for an option with the given name
 154  */
 155 QEMUOptionParameter *get_option_parameter(QEMUOptionParameter *list,
 156     const char *name)
 157 {
 158     while (list && list->name) {
 159         if (!strcmp(list->name, name)) {
 160             return list;
 161         }
 162         list++;
 163     }
 164
 165     return NULL;
 166 }
 167
 168 static int parse_option_bool(const char *name, const char *value, int *ret)
 169 {
 170     if (value != NULL) {
 171         if (!strcmp(value, "on")) {
 172             *ret = 1;
 173         } else if (!strcmp(value, "off")) {
 174             *ret = 0;
 175         } else {
 176             fprintf(stderr, "Option '%s': Use 'on' or 'off'\n", name);
 177             return -1;
 178         }
 179     } else {
 180         *ret = 1;
 181     }
 182     return 0;
 183 }
 184
 185 static int parse_option_number(const char *name, const char *value, uint64_t *ret)
 186 {
 187     char *postfix;
 188     uint64_t number;
 189
 190     if (value != NULL) {
 191         number = strtoull(value, &postfix, 0);
 192         if (*postfix != '\0') {
 193             fprintf(stderr, "Option '%s' needs a number as parameter\n", name);
 194             return -1;
 195         }
 196         *ret = number;
 197     } else {
 198         fprintf(stderr, "Option '%s' needs a parameter\n", name);
 199         return -1;
 200     }
 201     return 0;
 202 }
 203
 204 static int parse_option_size(const char *name, const char *value, uint64_t *ret)
 205 {
 206     char *postfix;
 207     double sizef;
 208
 209     if (value != NULL) {
 210         sizef = strtod(value, &postfix);
 211         switch (*postfix) {
 212         case 'T':
 213             sizef *= 1024;
 214         case 'G':
 215             sizef *= 1024;
 216         case 'M':
 217             sizef *= 1024;
 218         case 'K':
 219         case 'k':
 220             sizef *= 1024;
 221         case 'b':
 222         case '\0':
 223             *ret = (uint64_t) sizef;
 224             break;
 225         default:
 226             fprintf(stderr, "Option '%s' needs size as parameter\n", name);
 227             fprintf(stderr, "You may use k, M, G or T suffixes for "
 228                     "kilobytes, megabytes, gigabytes and terabytes.\n");
 229             return -1;
 230         }
 231     } else {
 232         fprintf(stderr, "Option '%s' needs a parameter\n", name);
 233         return -1;
 234     }
 235     return 0;
 236 }
 237
 238 /*
 239  * Sets the value of a parameter in a given option list. The parsing of the
 240  * value depends on the type of option:
 241  *
 242  * OPT_FLAG (uses value.n):
 243  *      If no value is given, the flag is set to 1.
 244  *      Otherwise the value must be "on" (set to 1) or "off" (set to 0)
 245  *
 246  * OPT_STRING (uses value.s):
 247  *      value is strdup()ed and assigned as option value
 248  *
 249  * OPT_SIZE (uses value.n):
 250  *      The value is converted to an integer. Suffixes for kilobytes etc. are
 251  *      allowed (powers of 1024).
 252  *
 253  * Returns 0 on succes, -1 in error cases
 254  */
 255 int set_option_parameter(QEMUOptionParameter *list, const char *name,
 256     const char *value)
 257 {
 258     int flag;
 259
 260     // Find a matching parameter
 261     list = get_option_parameter(list, name);
 262     if (list == NULL) {
 263         fprintf(stderr, "Unknown option '%s'\n", name);
 264         return -1;
 265     }
 266
 267     // Process parameter
 268     switch (list->type) {
 269     case OPT_FLAG:
 270         if (parse_option_bool(name, value, &flag) == -1)
 271             return -1;
 272         list->value.n = flag;
 273         break;
 274
 275     case OPT_STRING:
 276         if (value != NULL) {
 277             list->value.s = qemu_strdup(value);
 278         } else {
 279             fprintf(stderr, "Option '%s' needs a parameter\n", name);
 280             return -1;
 281         }
 282         break;
 283
 284     case OPT_SIZE:
 285         if (parse_option_size(name, value, &list->value.n) == -1)
 286             return -1;
 287         break;
 288
 289     default:
 290         fprintf(stderr, "Bug: Option '%s' has an unknown type\n", name);
 291         return -1;
 292     }
 293
 294     return 0;
 295 }
 296
 297 /*
 298  * Sets the given parameter to an integer instead of a string.
 299  * This function cannot be used to set string options.
 300  *
 301  * Returns 0 on success, -1 in error cases
 302  */
 303 int set_option_parameter_int(QEMUOptionParameter *list, const char *name,
 304     uint64_t value)
 305 {
 306     // Find a matching parameter
 307     list = get_option_parameter(list, name);
 308     if (list == NULL) {
 309         fprintf(stderr, "Unknown option '%s'\n", name);
 310         return -1;
 311     }
 312
 313     // Process parameter
 314     switch (list->type) {
 315     case OPT_FLAG:
 316     case OPT_NUMBER:
 317     case OPT_SIZE:
 318         list->value.n = value;
 319         break;
 320
 321     default:
 322         return -1;
 323     }
 324
 325     return 0;
 326 }
 327
 328 /*
 329  * Frees a option list. If it contains strings, the strings are freed as well.
 330  */
 331 void free_option_parameters(QEMUOptionParameter *list)
 332 {
 333     QEMUOptionParameter *cur = list;
 334
 335     while (cur && cur->name) {
 336         if (cur->type == OPT_STRING) {
 337             qemu_free(cur->value.s);
 338         }
 339         cur++;
 340     }
 341
 342     qemu_free(list);
 343 }
 344
 345 /*
 346  * Parses a parameter string (param) into an option list (dest).
 347  *
 348  * list is the templace is. If dest is NULL, a new copy of list is created for
 349  * it. If list is NULL, this function fails.
 350  *
 351  * A parameter string consists of one or more parameters, separated by commas.
 352  * Each parameter consists of its name and possibly of a value. In the latter
 353  * case, the value is delimited by an = character. To specify a value which
 354  * contains commas, double each comma so it won't be recognized as the end of
 355  * the parameter.
 356  *
 357  * For more details of the parsing see above.
 358  *
 359  * Returns a pointer to the first element of dest (or the newly allocated copy)
 360  * or NULL in error cases
 361  */
 362 QEMUOptionParameter *parse_option_parameters(const char *param,
 363     QEMUOptionParameter *list, QEMUOptionParameter *dest)
 364 {
 365     QEMUOptionParameter *cur;
 366     QEMUOptionParameter *allocated = NULL;
 367     char name[256];
 368     char value[256];
 369     char *param_delim, *value_delim;
 370     char next_delim;
 371     size_t num_options;
 372
 373     if (list == NULL) {
 374         return NULL;
 375     }
 376
 377     if (dest == NULL) {
 378         // Count valid options
 379         num_options = 0;
 380         cur = list;
 381         while (cur->name) {
 382             num_options++;
 383             cur++;
 384         }
 385
 386         // Create a copy of the option list to fill in values
 387         dest = qemu_mallocz((num_options + 1) * sizeof(QEMUOptionParameter));
 388         allocated = dest;
 389         memcpy(dest, list, (num_options + 1) * sizeof(QEMUOptionParameter));
 390     }
 391
 392     while (*param) {
 393
 394         // Find parameter name and value in the string
 395         param_delim = strchr(param, ',');
 396         value_delim = strchr(param, '=');
 397
 398         if (value_delim && (value_delim < param_delim || !param_delim)) {
 399             next_delim = '=';
 400         } else {
 401             next_delim = ',';
 402             value_delim = NULL;
 403         }
 404
 405         param = get_opt_name(name, sizeof(name), param, next_delim);
 406         if (value_delim) {
 407             param = get_opt_value(value, sizeof(value), param + 1);
 408         }
 409         if (*param != '\0') {
 410             param++;
 411         }
 412
 413         // Set the parameter
 414         if (set_option_parameter(dest, name, value_delim ? value : NULL)) {
 415             goto fail;
 416         }
 417     }
 418
 419     return dest;
 420
 421 fail:
 422     // Only free the list if it was newly allocated
 423     free_option_parameters(allocated);
 424     return NULL;
 425 }
 426
 427 /*
 428  * Prints all options of a list that have a value to stdout
 429  */
 430 void print_option_parameters(QEMUOptionParameter *list)
 431 {
 432     while (list && list->name) {
 433         switch (list->type) {
 434             case OPT_STRING:
 435                  if (list->value.s != NULL) {
 436                      printf("%s='%s' ", list->name, list->value.s);
 437                  }
 438                 break;
 439             case OPT_FLAG:
 440                 printf("%s=%s ", list->name, list->value.n ? "on" : "off");
 441                 break;
 442             case OPT_SIZE:
 443             case OPT_NUMBER:
 444                 printf("%s=%" PRId64 " ", list->name, list->value.n);
 445                 break;
 446             default:
 447                 printf("%s=(unkown type) ", list->name);
 448                 break;
 449         }
 450         list++;
 451     }
 452 }
 453
 454 /*
 455  * Prints an overview of all available options
 456  */
 457 void print_option_help(QEMUOptionParameter *list)
 458 {
 459     printf("Supported options:\n");
 460     while (list && list->name) {
 461         printf("%-16s %s\n", list->name,
 462             list->help ? list->help : "No description available");
 463         list++;
 464     }
 465 }
 466
 467 /* ------------------------------------------------------------------ */
 468
 469 struct QemuOpt {
 470     const char   *name;
 471     const char   *str;
 472
 473     QemuOptDesc  *desc;
 474     union {
 475         int      boolean;
 476         uint64_t uint;
 477     } value;
 478
 479     QemuOpts     *opts;
 480     QTAILQ_ENTRY(QemuOpt) next;
 481 };
 482
 483 struct QemuOpts {
 484     const char *id;
 485     QemuOptsList *list;
 486     QTAILQ_HEAD(, QemuOpt) head;
 487     QTAILQ_ENTRY(QemuOpts) next;
 488 };
 489
 490 static QemuOpt *qemu_opt_find(QemuOpts *opts, const char *name)
 491 {
 492     QemuOpt *opt;
 493
 494     QTAILQ_FOREACH(opt, &opts->head, next) {
 495         if (strcmp(opt->name, name) != 0)
 496             continue;
 497         return opt;
 498     }
 499     return NULL;
 500 }
 501
 502 const char *qemu_opt_get(QemuOpts *opts, const char *name)
 503 {
 504     QemuOpt *opt = qemu_opt_find(opts, name);
 505     return opt ? opt->str : NULL;
 506 }
 507
 508 int qemu_opt_get_bool(QemuOpts *opts, const char *name, int defval)
 509 {
 510     QemuOpt *opt = qemu_opt_find(opts, name);
 511
 512     if (opt == NULL)
 513         return defval;
 514     assert(opt->desc && opt->desc->type == QEMU_OPT_BOOL);
 515     return opt->value.boolean;
 516 }
 517
 518 uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t defval)
 519 {
 520     QemuOpt *opt = qemu_opt_find(opts, name);
 521
 522     if (opt == NULL)
 523         return defval;
 524     assert(opt->desc && opt->desc->type == QEMU_OPT_NUMBER);
 525     return opt->value.uint;
 526 }
 527
 528 uint64_t qemu_opt_get_size(QemuOpts *opts, const char *name, uint64_t defval)
 529 {
 530     QemuOpt *opt = qemu_opt_find(opts, name);
 531
 532     if (opt == NULL)
 533         return defval;
 534     assert(opt->desc && opt->desc->type == QEMU_OPT_SIZE);
 535     return opt->value.uint;
 536 }
 537
 538 static int qemu_opt_parse(QemuOpt *opt)
 539 {
 540     if (opt->desc == NULL)
 541         return 0;
 542     switch (opt->desc->type) {
 543     case QEMU_OPT_STRING:
 544         /* nothing */
 545         return 0;
 546     case QEMU_OPT_BOOL:
 547         return parse_option_bool(opt->name, opt->str, &opt->value.boolean);
 548     case QEMU_OPT_NUMBER:
 549         return parse_option_number(opt->name, opt->str, &opt->value.uint);
 550     case QEMU_OPT_SIZE:
 551         return parse_option_size(opt->name, opt->str, &opt->value.uint);
 552     default:
 553         abort();
 554     }
 555 }
 556
 557 static void qemu_opt_del(QemuOpt *opt)
 558 {
 559     QTAILQ_REMOVE(&opt->opts->head, opt, next);
 560     qemu_free((/* !const */ char*)opt->name);
 561     qemu_free((/* !const */ char*)opt->str);
 562     qemu_free(opt);
 563 }
 564
 565 int qemu_opt_set(QemuOpts *opts, const char *name, const char *value)
 566 {
 567     QemuOpt *opt;
 568
 569     opt = qemu_opt_find(opts, name);
 570     if (!opt) {
 571         QemuOptDesc *desc = opts->list->desc;
 572         int i;
 573
 574         for (i = 0; desc[i].name != NULL; i++) {
 575             if (strcmp(desc[i].name, name) == 0) {
 576                 break;
 577             }
 578         }
 579         if (desc[i].name == NULL) {
 580             if (i == 0) {
 581                 /* empty list -> allow any */;
 582             } else {
 583                 fprintf(stderr, "option \"%s\" is not valid for %s\n",
 584                         name, opts->list->name);
 585                 return -1;
 586             }
 587         }
 588         opt = qemu_mallocz(sizeof(*opt));
 589         opt->name = qemu_strdup(name);
 590         opt->opts = opts;
 591         QTAILQ_INSERT_TAIL(&opts->head, opt, next);
 592         if (desc[i].name != NULL) {
 593             opt->desc = desc+i;
 594         }
 595     }
 596     qemu_free((/* !const */ char*)opt->str);
 597     opt->str = NULL;
 598     if (value) {
 599         opt->str = qemu_strdup(value);
 600     }
 601     if (qemu_opt_parse(opt) < 0) {
 602         fprintf(stderr, "Failed to parse \"%s\" for \"%s.%s\"\n", opt->str,
 603                 opts->list->name, opt->name);
 604         qemu_opt_del(opt);
 605         return -1;
 606     }
 607     return 0;
 608 }
 609
 610 int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
 611                      int abort_on_failure)
 612 {
 613     QemuOpt *opt;
 614     int rc = 0;
 615
 616     QTAILQ_FOREACH(opt, &opts->head, next) {
 617         rc = func(opt->name, opt->str, opaque);
 618         if (abort_on_failure  &&  rc != 0)
 619             break;
 620     }
 621     return rc;
 622 }
 623
 624 QemuOpts *qemu_opts_find(QemuOptsList *list, const char *id)
 625 {
 626     QemuOpts *opts;
 627
 628     QTAILQ_FOREACH(opts, &list->head, next) {
 629         if (!opts->id) {
 630             continue;
 631         }
 632         if (strcmp(opts->id, id) != 0) {
 633             continue;
 634         }
 635         return opts;
 636     }
 637     return NULL;
 638 }
 639
 640 QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id, int fail_if_exists)
 641 {
 642     QemuOpts *opts = NULL;
 643
 644     if (id) {
 645         opts = qemu_opts_find(list, id);
 646         if (opts != NULL) {
 647             if (fail_if_exists) {
 648                 fprintf(stderr, "tried to create id \"%s\" twice for \"%s\"\n",
 649                         id, list->name);
 650                 return NULL;
 651             } else {
 652                 return opts;
 653             }
 654         }
 655     }
 656     opts = qemu_mallocz(sizeof(*opts));
 657     if (id) {
 658         opts->id = qemu_strdup(id);
 659     }
 660     opts->list = list;
 661     QTAILQ_INIT(&opts->head);
 662     QTAILQ_INSERT_TAIL(&list->head, opts, next);
 663     return opts;
 664 }
 665
 666 int qemu_opts_set(QemuOptsList *list, const char *id,
 667                   const char *name, const char *value)
 668 {
 669     QemuOpts *opts;
 670
 671     opts = qemu_opts_create(list, id, 1);
 672     if (opts == NULL) {
 673         fprintf(stderr, "id \"%s\" not found for \"%s\"\n",
 674                 id, list->name);
 675         return -1;
 676     }
 677     return qemu_opt_set(opts, name, value);
 678 }
 679
 680 const char *qemu_opts_id(QemuOpts *opts)
 681 {
 682     return opts->id;
 683 }
 684
 685 void qemu_opts_del(QemuOpts *opts)
 686 {
 687     QemuOpt *opt;
 688
 689     for (;;) {
 690         opt = QTAILQ_FIRST(&opts->head);
 691         if (opt == NULL)
 692             break;
 693         qemu_opt_del(opt);
 694     }
 695     QTAILQ_REMOVE(&opts->list->head, opts, next);
 696     qemu_free(opts);
 697 }
 698
 699 int qemu_opts_print(QemuOpts *opts, void *dummy)
 700 {
 701     QemuOpt *opt;
 702
 703     fprintf(stderr, "%s: %s:", opts->list->name,
 704             opts->id ? opts->id : "<noid>");
 705     QTAILQ_FOREACH(opt, &opts->head, next) {
 706         fprintf(stderr, " %s=\"%s\"", opt->name, opt->str);
 707     }
 708     fprintf(stderr, "\n");
 709     return 0;
 710 }
 711
 712 int qemu_opts_do_parse(QemuOpts *opts, const char *params, const char *firstname)
 713 {
 714     char option[128], value[128];
 715     const char *p,*pe,*pc;
 716
 717     p = params;
 718     for(;;) {
 719         pe = strchr(p, '=');
 720         pc = strchr(p, ',');
 721         if (!pe || (pc && pc < pe)) {
 722             /* found "foo,more" */
 723             if (p == params && firstname) {
 724                 /* implicitly named first option */
 725                 pstrcpy(option, sizeof(option), firstname);
 726                 p = get_opt_value(value, sizeof(value), p);
 727             } else {
 728                 /* option without value, probably a flag */
 729                 p = get_opt_name(option, sizeof(option), p, ',');
 730                 if (strncmp(option, "no", 2) == 0) {
 731                     memmove(option, option+2, strlen(option+2)+1);
 732                     pstrcpy(value, sizeof(value), "off");
 733                 } else {
 734                     pstrcpy(value, sizeof(value), "on");
 735                 }
 736             }
 737         } else {
 738             /* found "foo=bar,more" */
 739             p = get_opt_name(option, sizeof(option), p, '=');
 740             if (*p != '=') {
 741                 break;
 742             }
 743             p++;
 744             p = get_opt_value(value, sizeof(value), p);
 745         }
 746         if (strcmp(option, "id") != 0) {
 747             /* store and parse */
 748             if (qemu_opt_set(opts, option, value) == -1) {
 749                 return -1;
 750             }
 751         }
 752         if (*p != ',') {
 753             break;
 754         }
 755         p++;
 756     }
 757     return 0;
 758 }
 759
 760 QemuOpts *qemu_opts_parse(QemuOptsList *list, const char *params, const char *firstname)
 761 {
 762     char value[128], *id = NULL;
 763     const char *p;
 764     QemuOpts *opts;
 765
 766     if (strncmp(params, "id=", 3) == 0) {
 767         get_opt_value(value, sizeof(value), params+3);
 768         id = qemu_strdup(value);
 769     } else if ((p = strstr(params, ",id=")) != NULL) {
 770         get_opt_value(value, sizeof(value), p+4);
 771         id = qemu_strdup(value);
 772     }
 773     opts = qemu_opts_create(list, id, 1);
 774     if (opts == NULL)
 775         return NULL;
 776
 777     if (qemu_opts_do_parse(opts, params, firstname) != 0) {
 778         qemu_opts_del(opts);
 779         return NULL;
 780     }
 781
 782     return opts;
 783 }
 784
 785 int qemu_opts_foreach(QemuOptsList *list, qemu_opts_loopfunc func, void *opaque,
 786                       int abort_on_failure)
 787 {
 788     QemuOpts *opts;
 789     int rc = 0;
 790
 791     QTAILQ_FOREACH(opts, &list->head, next) {
 792         rc = func(opts, opaque);
 793         if (abort_on_failure  &&  rc != 0)
 794             break;
 795     }
 796     return rc;
 797 }