util/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/error-report.h"
  31 #include "qapi/qmp/types.h"
  32 #include "qapi/error.h"
  33 #include "qapi/qmp/qerror.h"
  34 #include "qemu/option_int.h"
  35
  36 /*
  37  * Extracts the name of an option from the parameter string (p points at the
  38  * first byte of the option name)
  39  *
  40  * The option name is delimited by delim (usually , or =) or the string end
  41  * and is copied into buf. If the option name is longer than buf_size, it is
  42  * truncated. buf is always zero terminated.
  43  *
  44  * The return value is the position of the delimiter/zero byte after the option
  45  * name in p.
  46  */
  47 const char *get_opt_name(char *buf, int buf_size, const char *p, char delim)
  48 {
  49     char *q;
  50
  51     q = buf;
  52     while (*p != '\0' && *p != delim) {
  53         if (q && (q - buf) < buf_size - 1)
  54             *q++ = *p;
  55         p++;
  56     }
  57     if (q)
  58         *q = '\0';
  59
  60     return p;
  61 }
  62
  63 /*
  64  * Extracts the value of an option from the parameter string p (p points at the
  65  * first byte of the option value)
  66  *
  67  * This function is comparable to get_opt_name with the difference that the
  68  * delimiter is fixed to be comma which starts a new option. To specify an
  69  * option value that contains commas, double each comma.
  70  */
  71 const char *get_opt_value(char *buf, int buf_size, const char *p)
  72 {
  73     char *q;
  74
  75     q = buf;
  76     while (*p != '\0') {
  77         if (*p == ',') {
  78             if (*(p + 1) != ',')
  79                 break;
  80             p++;
  81         }
  82         if (q && (q - buf) < buf_size - 1)
  83             *q++ = *p;
  84         p++;
  85     }
  86     if (q)
  87         *q = '\0';
  88
  89     return p;
  90 }
  91
  92 int get_next_param_value(char *buf, int buf_size,
  93                          const char *tag, const char **pstr)
  94 {
  95     const char *p;
  96     char option[128];
  97
  98     p = *pstr;
  99     for(;;) {
 100         p = get_opt_name(option, sizeof(option), p, '=');
 101         if (*p != '=')
 102             break;
 103         p++;
 104         if (!strcmp(tag, option)) {
 105             *pstr = get_opt_value(buf, buf_size, p);
 106             if (**pstr == ',') {
 107                 (*pstr)++;
 108             }
 109             return strlen(buf);
 110         } else {
 111             p = get_opt_value(NULL, 0, p);
 112         }
 113         if (*p != ',')
 114             break;
 115         p++;
 116     }
 117     return 0;
 118 }
 119
 120 int get_param_value(char *buf, int buf_size,
 121                     const char *tag, const char *str)
 122 {
 123     return get_next_param_value(buf, buf_size, tag, &str);
 124 }
 125
 126 /*
 127  * Searches an option list for an option with the given name
 128  */
 129 QEMUOptionParameter *get_option_parameter(QEMUOptionParameter *list,
 130     const char *name)
 131 {
 132     while (list && list->name) {
 133         if (!strcmp(list->name, name)) {
 134             return list;
 135         }
 136         list++;
 137     }
 138
 139     return NULL;
 140 }
 141
 142 static void parse_option_bool(const char *name, const char *value, bool *ret,
 143                               Error **errp)
 144 {
 145     if (value != NULL) {
 146         if (!strcmp(value, "on")) {
 147             *ret = 1;
 148         } else if (!strcmp(value, "off")) {
 149             *ret = 0;
 150         } else {
 151             error_set(errp,QERR_INVALID_PARAMETER_VALUE, name, "'on' or 'off'");
 152         }
 153     } else {
 154         *ret = 1;
 155     }
 156 }
 157
 158 static void parse_option_number(const char *name, const char *value,
 159                                 uint64_t *ret, Error **errp)
 160 {
 161     char *postfix;
 162     uint64_t number;
 163
 164     if (value != NULL) {
 165         number = strtoull(value, &postfix, 0);
 166         if (*postfix != '\0') {
 167             error_set(errp, QERR_INVALID_PARAMETER_VALUE, name, "a number");
 168             return;
 169         }
 170         *ret = number;
 171     } else {
 172         error_set(errp, QERR_INVALID_PARAMETER_VALUE, name, "a number");
 173     }
 174 }
 175
 176 static const QemuOptDesc *find_desc_by_name(const QemuOptDesc *desc,
 177                                             const char *name)
 178 {
 179     int i;
 180
 181     for (i = 0; desc[i].name != NULL; i++) {
 182         if (strcmp(desc[i].name, name) == 0) {
 183             return &desc[i];
 184         }
 185     }
 186
 187     return NULL;
 188 }
 189
 190 void parse_option_size(const char *name, const char *value,
 191                        uint64_t *ret, Error **errp)
 192 {
 193     char *postfix;
 194     double sizef;
 195
 196     if (value != NULL) {
 197         sizef = strtod(value, &postfix);
 198         switch (*postfix) {
 199         case 'T':
 200             sizef *= 1024;
 201             /* fall through */
 202         case 'G':
 203             sizef *= 1024;
 204             /* fall through */
 205         case 'M':
 206             sizef *= 1024;
 207             /* fall through */
 208         case 'K':
 209         case 'k':
 210             sizef *= 1024;
 211             /* fall through */
 212         case 'b':
 213         case '\0':
 214             *ret = (uint64_t) sizef;
 215             break;
 216         default:
 217             error_set(errp, QERR_INVALID_PARAMETER_VALUE, name, "a size");
 218 #if 0 /* conversion from qerror_report() to error_set() broke this: */
 219             error_printf_unless_qmp("You may use k, M, G or T suffixes for "
 220                     "kilobytes, megabytes, gigabytes and terabytes.\n");
 221 #endif
 222             return;
 223         }
 224     } else {
 225         error_set(errp, QERR_INVALID_PARAMETER_VALUE, name, "a size");
 226     }
 227 }
 228
 229 /*
 230  * Sets the value of a parameter in a given option list. The parsing of the
 231  * value depends on the type of option:
 232  *
 233  * OPT_FLAG (uses value.n):
 234  *      If no value is given, the flag is set to 1.
 235  *      Otherwise the value must be "on" (set to 1) or "off" (set to 0)
 236  *
 237  * OPT_STRING (uses value.s):
 238  *      value is strdup()ed and assigned as option value
 239  *
 240  * OPT_SIZE (uses value.n):
 241  *      The value is converted to an integer. Suffixes for kilobytes etc. are
 242  *      allowed (powers of 1024).
 243  *
 244  * Returns 0 on succes, -1 in error cases
 245  */
 246 int set_option_parameter(QEMUOptionParameter *list, const char *name,
 247     const char *value)
 248 {
 249     bool flag;
 250     Error *local_err = NULL;
 251
 252     // Find a matching parameter
 253     list = get_option_parameter(list, name);
 254     if (list == NULL) {
 255         fprintf(stderr, "Unknown option '%s'\n", name);
 256         return -1;
 257     }
 258
 259     // Process parameter
 260     switch (list->type) {
 261     case OPT_FLAG:
 262         parse_option_bool(name, value, &flag, &local_err);
 263         if (!local_err) {
 264             list->value.n = flag;
 265         }
 266         break;
 267
 268     case OPT_STRING:
 269         if (value != NULL) {
 270             list->value.s = g_strdup(value);
 271         } else {
 272             fprintf(stderr, "Option '%s' needs a parameter\n", name);
 273             return -1;
 274         }
 275         break;
 276
 277     case OPT_SIZE:
 278         parse_option_size(name, value, &list->value.n, &local_err);
 279         break;
 280
 281     default:
 282         fprintf(stderr, "Bug: Option '%s' has an unknown type\n", name);
 283         return -1;
 284     }
 285
 286     if (local_err) {
 287         qerror_report_err(local_err);
 288         error_free(local_err);
 289         return -1;
 290     }
 291
 292     list->assigned = true;
 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     list->assigned = true;
 326
 327     return 0;
 328 }
 329
 330 /*
 331  * Frees a option list. If it contains strings, the strings are freed as well.
 332  */
 333 void free_option_parameters(QEMUOptionParameter *list)
 334 {
 335     QEMUOptionParameter *cur = list;
 336
 337     while (cur && cur->name) {
 338         if (cur->type == OPT_STRING) {
 339             g_free(cur->value.s);
 340         }
 341         cur++;
 342     }
 343
 344     g_free(list);
 345 }
 346
 347 /*
 348  * Count valid options in list
 349  */
 350 static size_t count_option_parameters(QEMUOptionParameter *list)
 351 {
 352     size_t num_options = 0;
 353
 354     while (list && list->name) {
 355         num_options++;
 356         list++;
 357     }
 358
 359     return num_options;
 360 }
 361
 362 /*
 363  * Append an option list (list) to an option list (dest).
 364  *
 365  * If dest is NULL, a new copy of list is created.
 366  *
 367  * Returns a pointer to the first element of dest (or the newly allocated copy)
 368  */
 369 QEMUOptionParameter *append_option_parameters(QEMUOptionParameter *dest,
 370     QEMUOptionParameter *list)
 371 {
 372     size_t num_options, num_dest_options;
 373
 374     num_options = count_option_parameters(dest);
 375     num_dest_options = num_options;
 376
 377     num_options += count_option_parameters(list);
 378
 379     dest = g_realloc(dest, (num_options + 1) * sizeof(QEMUOptionParameter));
 380     dest[num_dest_options].name = NULL;
 381
 382     while (list && list->name) {
 383         if (get_option_parameter(dest, list->name) == NULL) {
 384             dest[num_dest_options++] = *list;
 385             dest[num_dest_options].name = NULL;
 386         }
 387         list++;
 388     }
 389
 390     return dest;
 391 }
 392
 393 /*
 394  * Parses a parameter string (param) into an option list (dest).
 395  *
 396  * list is the template option list. If dest is NULL, a new copy of list is
 397  * created. If list is NULL, this function fails.
 398  *
 399  * A parameter string consists of one or more parameters, separated by commas.
 400  * Each parameter consists of its name and possibly of a value. In the latter
 401  * case, the value is delimited by an = character. To specify a value which
 402  * contains commas, double each comma so it won't be recognized as the end of
 403  * the parameter.
 404  *
 405  * For more details of the parsing see above.
 406  *
 407  * Returns a pointer to the first element of dest (or the newly allocated copy)
 408  * or NULL in error cases
 409  */
 410 QEMUOptionParameter *parse_option_parameters(const char *param,
 411     QEMUOptionParameter *list, QEMUOptionParameter *dest)
 412 {
 413     QEMUOptionParameter *allocated = NULL;
 414     char name[256];
 415     char value[256];
 416     char *param_delim, *value_delim;
 417     char next_delim;
 418     int i;
 419
 420     if (list == NULL) {
 421         return NULL;
 422     }
 423
 424     if (dest == NULL) {
 425         dest = allocated = append_option_parameters(NULL, list);
 426     }
 427
 428     for (i = 0; dest[i].name; i++) {
 429         dest[i].assigned = false;
 430     }
 431
 432     while (*param) {
 433
 434         // Find parameter name and value in the string
 435         param_delim = strchr(param, ',');
 436         value_delim = strchr(param, '=');
 437
 438         if (value_delim && (value_delim < param_delim || !param_delim)) {
 439             next_delim = '=';
 440         } else {
 441             next_delim = ',';
 442             value_delim = NULL;
 443         }
 444
 445         param = get_opt_name(name, sizeof(name), param, next_delim);
 446         if (value_delim) {
 447             param = get_opt_value(value, sizeof(value), param + 1);
 448         }
 449         if (*param != '\0') {
 450             param++;
 451         }
 452
 453         // Set the parameter
 454         if (set_option_parameter(dest, name, value_delim ? value : NULL)) {
 455             goto fail;
 456         }
 457     }
 458
 459     return dest;
 460
 461 fail:
 462     // Only free the list if it was newly allocated
 463     free_option_parameters(allocated);
 464     return NULL;
 465 }
 466
 467 bool has_help_option(const char *param)
 468 {
 469     size_t buflen = strlen(param) + 1;
 470     char *buf = g_malloc0(buflen);
 471     const char *p = param;
 472     bool result = false;
 473
 474     while (*p) {
 475         p = get_opt_value(buf, buflen, p);
 476         if (*p) {
 477             p++;
 478         }
 479
 480         if (is_help_option(buf)) {
 481             result = true;
 482             goto out;
 483         }
 484     }
 485
 486 out:
 487     free(buf);
 488     return result;
 489 }
 490
 491 bool is_valid_option_list(const char *param)
 492 {
 493     size_t buflen = strlen(param) + 1;
 494     char *buf = g_malloc0(buflen);
 495     const char *p = param;
 496     bool result = true;
 497
 498     while (*p) {
 499         p = get_opt_value(buf, buflen, p);
 500         if (*p && !*++p) {
 501             result = false;
 502             goto out;
 503         }
 504
 505         if (!*buf || *buf == ',') {
 506             result = false;
 507             goto out;
 508         }
 509     }
 510
 511 out:
 512     free(buf);
 513     return result;
 514 }
 515
 516 /*
 517  * Prints all options of a list that have a value to stdout
 518  */
 519 void print_option_parameters(QEMUOptionParameter *list)
 520 {
 521     while (list && list->name) {
 522         switch (list->type) {
 523             case OPT_STRING:
 524                  if (list->value.s != NULL) {
 525                      printf("%s='%s' ", list->name, list->value.s);
 526                  }
 527                 break;
 528             case OPT_FLAG:
 529                 printf("%s=%s ", list->name, list->value.n ? "on" : "off");
 530                 break;
 531             case OPT_SIZE:
 532             case OPT_NUMBER:
 533                 printf("%s=%" PRId64 " ", list->name, list->value.n);
 534                 break;
 535             default:
 536                 printf("%s=(unknown type) ", list->name);
 537                 break;
 538         }
 539         list++;
 540     }
 541 }
 542
 543 /*
 544  * Prints an overview of all available options
 545  */
 546 void print_option_help(QEMUOptionParameter *list)
 547 {
 548     printf("Supported options:\n");
 549     while (list && list->name) {
 550         printf("%-16s %s\n", list->name,
 551             list->help ? list->help : "No description available");
 552         list++;
 553     }
 554 }
 555
 556 void qemu_opts_print_help(QemuOptsList *list)
 557 {
 558     QemuOptDesc *desc;
 559
 560     assert(list);
 561     desc = list->desc;
 562     printf("Supported options:\n");
 563     while (desc && desc->name) {
 564         printf("%-16s %s\n", desc->name,
 565                desc->help ? desc->help : "No description available");
 566         desc++;
 567     }
 568 }
 569 /* ------------------------------------------------------------------ */
 570
 571 static QemuOpt *qemu_opt_find(QemuOpts *opts, const char *name)
 572 {
 573     QemuOpt *opt;
 574
 575     QTAILQ_FOREACH_REVERSE(opt, &opts->head, QemuOptHead, next) {
 576         if (strcmp(opt->name, name) != 0)
 577             continue;
 578         return opt;
 579     }
 580     return NULL;
 581 }
 582
 583 static void qemu_opt_del(QemuOpt *opt)
 584 {
 585     QTAILQ_REMOVE(&opt->opts->head, opt, next);
 586     g_free(opt->name);
 587     g_free(opt->str);
 588     g_free(opt);
 589 }
 590
 591 /* qemu_opt_set allows many settings for the same option.
 592  * This function deletes all settings for an option.
 593  */
 594 static void qemu_opt_del_all(QemuOpts *opts, const char *name)
 595 {
 596     QemuOpt *opt, *next_opt;
 597
 598     QTAILQ_FOREACH_SAFE(opt, &opts->head, next, next_opt) {
 599         if (!strcmp(opt->name, name)) {
 600             qemu_opt_del(opt);
 601         }
 602     }
 603 }
 604
 605 const char *qemu_opt_get(QemuOpts *opts, const char *name)
 606 {
 607     QemuOpt *opt = qemu_opt_find(opts, name);
 608
 609     if (!opt) {
 610         const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
 611         if (desc && desc->def_value_str) {
 612             return desc->def_value_str;
 613         }
 614     }
 615     return opt ? opt->str : NULL;
 616 }
 617
 618 /* Get a known option (or its default) and remove it from the list
 619  * all in one action. Return a malloced string of the option value.
 620  * Result must be freed by caller with g_free().
 621  */
 622 char *qemu_opt_get_del(QemuOpts *opts, const char *name)
 623 {
 624     QemuOpt *opt;
 625     const QemuOptDesc *desc;
 626     char *str = NULL;
 627
 628     if (opts == NULL) {
 629         return NULL;
 630     }
 631
 632     opt = qemu_opt_find(opts, name);
 633     if (!opt) {
 634         desc = find_desc_by_name(opts->list->desc, name);
 635         if (desc && desc->def_value_str) {
 636             str = g_strdup(desc->def_value_str);
 637         }
 638         return str;
 639     }
 640     str = opt->str;
 641     opt->str = NULL;
 642     qemu_opt_del_all(opts, name);
 643     return str;
 644 }
 645
 646 bool qemu_opt_has_help_opt(QemuOpts *opts)
 647 {
 648     QemuOpt *opt;
 649
 650     QTAILQ_FOREACH_REVERSE(opt, &opts->head, QemuOptHead, next) {
 651         if (is_help_option(opt->name)) {
 652             return true;
 653         }
 654     }
 655     return false;
 656 }
 657
 658 static bool qemu_opt_get_bool_helper(QemuOpts *opts, const char *name,
 659                                      bool defval, bool del)
 660 {
 661     QemuOpt *opt = qemu_opt_find(opts, name);
 662     bool ret = defval;
 663
 664     if (opt == NULL) {
 665         const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
 666         if (desc && desc->def_value_str) {
 667             parse_option_bool(name, desc->def_value_str, &ret, &error_abort);
 668         }
 669         return ret;
 670     }
 671     assert(opt->desc && opt->desc->type == QEMU_OPT_BOOL);
 672     ret = opt->value.boolean;
 673     if (del) {
 674         qemu_opt_del_all(opts, name);
 675     }
 676     return ret;
 677 }
 678
 679 bool qemu_opt_get_bool(QemuOpts *opts, const char *name, bool defval)
 680 {
 681     return qemu_opt_get_bool_helper(opts, name, defval, false);
 682 }
 683
 684 bool qemu_opt_get_bool_del(QemuOpts *opts, const char *name, bool defval)
 685 {
 686     return qemu_opt_get_bool_helper(opts, name, defval, true);
 687 }
 688
 689 static uint64_t qemu_opt_get_number_helper(QemuOpts *opts, const char *name,
 690                                            uint64_t defval, bool del)
 691 {
 692     QemuOpt *opt = qemu_opt_find(opts, name);
 693     uint64_t ret = defval;
 694
 695     if (opt == NULL) {
 696         const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
 697         if (desc && desc->def_value_str) {
 698             parse_option_number(name, desc->def_value_str, &ret, &error_abort);
 699         }
 700         return ret;
 701     }
 702     assert(opt->desc && opt->desc->type == QEMU_OPT_NUMBER);
 703     ret = opt->value.uint;
 704     if (del) {
 705         qemu_opt_del_all(opts, name);
 706     }
 707     return ret;
 708 }
 709
 710 uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t defval)
 711 {
 712     return qemu_opt_get_number_helper(opts, name, defval, false);
 713 }
 714
 715 uint64_t qemu_opt_get_number_del(QemuOpts *opts, const char *name,
 716                                  uint64_t defval)
 717 {
 718     return qemu_opt_get_number_helper(opts, name, defval, true);
 719 }
 720
 721 static uint64_t qemu_opt_get_size_helper(QemuOpts *opts, const char *name,
 722                                          uint64_t defval, bool del)
 723 {
 724     QemuOpt *opt = qemu_opt_find(opts, name);
 725     uint64_t ret = defval;
 726
 727     if (opt == NULL) {
 728         const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
 729         if (desc && desc->def_value_str) {
 730             parse_option_size(name, desc->def_value_str, &ret, &error_abort);
 731         }
 732         return ret;
 733     }
 734     assert(opt->desc && opt->desc->type == QEMU_OPT_SIZE);
 735     ret = opt->value.uint;
 736     if (del) {
 737         qemu_opt_del_all(opts, name);
 738     }
 739     return ret;
 740 }
 741
 742 uint64_t qemu_opt_get_size(QemuOpts *opts, const char *name, uint64_t defval)
 743 {
 744     return qemu_opt_get_size_helper(opts, name, defval, false);
 745 }
 746
 747 uint64_t qemu_opt_get_size_del(QemuOpts *opts, const char *name,
 748                                uint64_t defval)
 749 {
 750     return qemu_opt_get_size_helper(opts, name, defval, true);
 751 }
 752
 753 static void qemu_opt_parse(QemuOpt *opt, Error **errp)
 754 {
 755     if (opt->desc == NULL)
 756         return;
 757
 758     switch (opt->desc->type) {
 759     case QEMU_OPT_STRING:
 760         /* nothing */
 761         return;
 762     case QEMU_OPT_BOOL:
 763         parse_option_bool(opt->name, opt->str, &opt->value.boolean, errp);
 764         break;
 765     case QEMU_OPT_NUMBER:
 766         parse_option_number(opt->name, opt->str, &opt->value.uint, errp);
 767         break;
 768     case QEMU_OPT_SIZE:
 769         parse_option_size(opt->name, opt->str, &opt->value.uint, errp);
 770         break;
 771     default:
 772         abort();
 773     }
 774 }
 775
 776 static bool opts_accepts_any(const QemuOpts *opts)
 777 {
 778     return opts->list->desc[0].name == NULL;
 779 }
 780
 781 int qemu_opt_unset(QemuOpts *opts, const char *name)
 782 {
 783     QemuOpt *opt = qemu_opt_find(opts, name);
 784
 785     assert(opts_accepts_any(opts));
 786
 787     if (opt == NULL) {
 788         return -1;
 789     } else {
 790         qemu_opt_del(opt);
 791         return 0;
 792     }
 793 }
 794
 795 static void opt_set(QemuOpts *opts, const char *name, const char *value,
 796                     bool prepend, Error **errp)
 797 {
 798     QemuOpt *opt;
 799     const QemuOptDesc *desc;
 800     Error *local_err = NULL;
 801
 802     desc = find_desc_by_name(opts->list->desc, name);
 803     if (!desc && !opts_accepts_any(opts)) {
 804         error_set(errp, QERR_INVALID_PARAMETER, name);
 805         return;
 806     }
 807
 808     opt = g_malloc0(sizeof(*opt));
 809     opt->name = g_strdup(name);
 810     opt->opts = opts;
 811     if (prepend) {
 812         QTAILQ_INSERT_HEAD(&opts->head, opt, next);
 813     } else {
 814         QTAILQ_INSERT_TAIL(&opts->head, opt, next);
 815     }
 816     opt->desc = desc;
 817     opt->str = g_strdup(value);
 818     qemu_opt_parse(opt, &local_err);
 819     if (local_err) {
 820         error_propagate(errp, local_err);
 821         qemu_opt_del(opt);
 822     }
 823 }
 824
 825 int qemu_opt_set(QemuOpts *opts, const char *name, const char *value)
 826 {
 827     Error *local_err = NULL;
 828
 829     opt_set(opts, name, value, false, &local_err);
 830     if (local_err) {
 831         qerror_report_err(local_err);
 832         error_free(local_err);
 833         return -1;
 834     }
 835
 836     return 0;
 837 }
 838
 839 void qemu_opt_set_err(QemuOpts *opts, const char *name, const char *value,
 840                       Error **errp)
 841 {
 842     opt_set(opts, name, value, false, errp);
 843 }
 844
 845 int qemu_opt_set_bool(QemuOpts *opts, const char *name, bool val)
 846 {
 847     QemuOpt *opt;
 848     const QemuOptDesc *desc = opts->list->desc;
 849
 850     opt = g_malloc0(sizeof(*opt));
 851     opt->desc = find_desc_by_name(desc, name);
 852     if (!opt->desc && !opts_accepts_any(opts)) {
 853         qerror_report(QERR_INVALID_PARAMETER, name);
 854         g_free(opt);
 855         return -1;
 856     }
 857
 858     opt->name = g_strdup(name);
 859     opt->opts = opts;
 860     opt->value.boolean = !!val;
 861     opt->str = g_strdup(val ? "on" : "off");
 862     QTAILQ_INSERT_TAIL(&opts->head, opt, next);
 863
 864     return 0;
 865 }
 866
 867 int qemu_opt_set_number(QemuOpts *opts, const char *name, int64_t val)
 868 {
 869     QemuOpt *opt;
 870     const QemuOptDesc *desc = opts->list->desc;
 871
 872     opt = g_malloc0(sizeof(*opt));
 873     opt->desc = find_desc_by_name(desc, name);
 874     if (!opt->desc && !opts_accepts_any(opts)) {
 875         qerror_report(QERR_INVALID_PARAMETER, name);
 876         g_free(opt);
 877         return -1;
 878     }
 879
 880     opt->name = g_strdup(name);
 881     opt->opts = opts;
 882     opt->value.uint = val;
 883     opt->str = g_strdup_printf("%" PRId64, val);
 884     QTAILQ_INSERT_TAIL(&opts->head, opt, next);
 885
 886     return 0;
 887 }
 888
 889 int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
 890                      int abort_on_failure)
 891 {
 892     QemuOpt *opt;
 893     int rc = 0;
 894
 895     QTAILQ_FOREACH(opt, &opts->head, next) {
 896         rc = func(opt->name, opt->str, opaque);
 897         if (abort_on_failure  &&  rc != 0)
 898             break;
 899     }
 900     return rc;
 901 }
 902
 903 QemuOpts *qemu_opts_find(QemuOptsList *list, const char *id)
 904 {
 905     QemuOpts *opts;
 906
 907     QTAILQ_FOREACH(opts, &list->head, next) {
 908         if (!opts->id && !id) {
 909             return opts;
 910         }
 911         if (opts->id && id && !strcmp(opts->id, id)) {
 912             return opts;
 913         }
 914     }
 915     return NULL;
 916 }
 917
 918 static int id_wellformed(const char *id)
 919 {
 920     int i;
 921
 922     if (!qemu_isalpha(id[0])) {
 923         return 0;
 924     }
 925     for (i = 1; id[i]; i++) {
 926         if (!qemu_isalnum(id[i]) && !strchr("-._", id[i])) {
 927             return 0;
 928         }
 929     }
 930     return 1;
 931 }
 932
 933 QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id,
 934                            int fail_if_exists, Error **errp)
 935 {
 936     QemuOpts *opts = NULL;
 937
 938     if (id) {
 939         if (!id_wellformed(id)) {
 940             error_set(errp,QERR_INVALID_PARAMETER_VALUE, "id", "an identifier");
 941 #if 0 /* conversion from qerror_report() to error_set() broke this: */
 942             error_printf_unless_qmp("Identifiers consist of letters, digits, '-', '.', '_', starting with a letter.\n");
 943 #endif
 944             return NULL;
 945         }
 946         opts = qemu_opts_find(list, id);
 947         if (opts != NULL) {
 948             if (fail_if_exists && !list->merge_lists) {
 949                 error_setg(errp, "Duplicate ID '%s' for %s", id, list->name);
 950                 return NULL;
 951             } else {
 952                 return opts;
 953             }
 954         }
 955     } else if (list->merge_lists) {
 956         opts = qemu_opts_find(list, NULL);
 957         if (opts) {
 958             return opts;
 959         }
 960     }
 961     opts = g_malloc0(sizeof(*opts));
 962     opts->id = g_strdup(id);
 963     opts->list = list;
 964     loc_save(&opts->loc);
 965     QTAILQ_INIT(&opts->head);
 966     QTAILQ_INSERT_TAIL(&list->head, opts, next);
 967     return opts;
 968 }
 969
 970 void qemu_opts_reset(QemuOptsList *list)
 971 {
 972     QemuOpts *opts, *next_opts;
 973
 974     QTAILQ_FOREACH_SAFE(opts, &list->head, next, next_opts) {
 975         qemu_opts_del(opts);
 976     }
 977 }
 978
 979 void qemu_opts_loc_restore(QemuOpts *opts)
 980 {
 981     loc_restore(&opts->loc);
 982 }
 983
 984 int qemu_opts_set(QemuOptsList *list, const char *id,
 985                   const char *name, const char *value)
 986 {
 987     QemuOpts *opts;
 988     Error *local_err = NULL;
 989
 990     opts = qemu_opts_create(list, id, 1, &local_err);
 991     if (local_err) {
 992         qerror_report_err(local_err);
 993         error_free(local_err);
 994         return -1;
 995     }
 996     return qemu_opt_set(opts, name, value);
 997 }
 998
 999 const char *qemu_opts_id(QemuOpts *opts)
1000 {
1001     return opts->id;
1002 }
1003
1004 /* The id string will be g_free()d by qemu_opts_del */
1005 void qemu_opts_set_id(QemuOpts *opts, char *id)
1006 {
1007     opts->id = id;
1008 }
1009
1010 void qemu_opts_del(QemuOpts *opts)
1011 {
1012     QemuOpt *opt;
1013
1014     if (opts == NULL) {
1015         return;
1016     }
1017
1018     for (;;) {
1019         opt = QTAILQ_FIRST(&opts->head);
1020         if (opt == NULL)
1021             break;
1022         qemu_opt_del(opt);
1023     }
1024     QTAILQ_REMOVE(&opts->list->head, opts, next);
1025     g_free(opts->id);
1026     g_free(opts);
1027 }
1028
1029 void qemu_opts_print(QemuOpts *opts)
1030 {
1031     QemuOpt *opt;
1032     QemuOptDesc *desc = opts->list->desc;
1033
1034     if (desc[0].name == NULL) {
1035         QTAILQ_FOREACH(opt, &opts->head, next) {
1036             printf("%s=\"%s\" ", opt->name, opt->str);
1037         }
1038         return;
1039     }
1040     for (; desc && desc->name; desc++) {
1041         const char *value;
1042         QemuOpt *opt = qemu_opt_find(opts, desc->name);
1043
1044         value = opt ? opt->str : desc->def_value_str;
1045         if (!value) {
1046             continue;
1047         }
1048         if (desc->type == QEMU_OPT_STRING) {
1049             printf("%s='%s' ", desc->name, value);
1050         } else if ((desc->type == QEMU_OPT_SIZE ||
1051                     desc->type == QEMU_OPT_NUMBER) && opt) {
1052             printf("%s=%" PRId64 " ", desc->name, opt->value.uint);
1053         } else {
1054             printf("%s=%s ", desc->name, value);
1055         }
1056     }
1057 }
1058
1059 static int opts_do_parse(QemuOpts *opts, const char *params,
1060                          const char *firstname, bool prepend)
1061 {
1062     char option[128], value[1024];
1063     const char *p,*pe,*pc;
1064     Error *local_err = NULL;
1065
1066     for (p = params; *p != '\0'; p++) {
1067         pe = strchr(p, '=');
1068         pc = strchr(p, ',');
1069         if (!pe || (pc && pc < pe)) {
1070             /* found "foo,more" */
1071             if (p == params && firstname) {
1072                 /* implicitly named first option */
1073                 pstrcpy(option, sizeof(option), firstname);
1074                 p = get_opt_value(value, sizeof(value), p);
1075             } else {
1076                 /* option without value, probably a flag */
1077                 p = get_opt_name(option, sizeof(option), p, ',');
1078                 if (strncmp(option, "no", 2) == 0) {
1079                     memmove(option, option+2, strlen(option+2)+1);
1080                     pstrcpy(value, sizeof(value), "off");
1081                 } else {
1082                     pstrcpy(value, sizeof(value), "on");
1083                 }
1084             }
1085         } else {
1086             /* found "foo=bar,more" */
1087             p = get_opt_name(option, sizeof(option), p, '=');
1088             if (*p != '=') {
1089                 break;
1090             }
1091             p++;
1092             p = get_opt_value(value, sizeof(value), p);
1093         }
1094         if (strcmp(option, "id") != 0) {
1095             /* store and parse */
1096             opt_set(opts, option, value, prepend, &local_err);
1097             if (local_err) {
1098                 qerror_report_err(local_err);
1099                 error_free(local_err);
1100                 return -1;
1101             }
1102         }
1103         if (*p != ',') {
1104             break;
1105         }
1106     }
1107     return 0;
1108 }
1109
1110 int qemu_opts_do_parse(QemuOpts *opts, const char *params, const char *firstname)
1111 {
1112     return opts_do_parse(opts, params, firstname, false);
1113 }
1114
1115 static QemuOpts *opts_parse(QemuOptsList *list, const char *params,
1116                             int permit_abbrev, bool defaults)
1117 {
1118     const char *firstname;
1119     char value[1024], *id = NULL;
1120     const char *p;
1121     QemuOpts *opts;
1122     Error *local_err = NULL;
1123
1124     assert(!permit_abbrev || list->implied_opt_name);
1125     firstname = permit_abbrev ? list->implied_opt_name : NULL;
1126
1127     if (strncmp(params, "id=", 3) == 0) {
1128         get_opt_value(value, sizeof(value), params+3);
1129         id = value;
1130     } else if ((p = strstr(params, ",id=")) != NULL) {
1131         get_opt_value(value, sizeof(value), p+4);
1132         id = value;
1133     }
1134
1135     /*
1136      * This code doesn't work for defaults && !list->merge_lists: when
1137      * params has no id=, and list has an element with !opts->id, it
1138      * appends a new element instead of returning the existing opts.
1139      * However, we got no use for this case.  Guard against possible
1140      * (if unlikely) future misuse:
1141      */
1142     assert(!defaults || list->merge_lists);
1143     opts = qemu_opts_create(list, id, !defaults, &local_err);
1144     if (opts == NULL) {
1145         if (local_err) {
1146             qerror_report_err(local_err);
1147             error_free(local_err);
1148         }
1149         return NULL;
1150     }
1151
1152     if (opts_do_parse(opts, params, firstname, defaults) != 0) {
1153         qemu_opts_del(opts);
1154         return NULL;
1155     }
1156
1157     return opts;
1158 }
1159
1160 QemuOpts *qemu_opts_parse(QemuOptsList *list, const char *params,
1161                           int permit_abbrev)
1162 {
1163     return opts_parse(list, params, permit_abbrev, false);
1164 }
1165
1166 void qemu_opts_set_defaults(QemuOptsList *list, const char *params,
1167                             int permit_abbrev)
1168 {
1169     QemuOpts *opts;
1170
1171     opts = opts_parse(list, params, permit_abbrev, true);
1172     assert(opts);
1173 }
1174
1175 typedef struct OptsFromQDictState {
1176     QemuOpts *opts;
1177     Error **errp;
1178 } OptsFromQDictState;
1179
1180 static void qemu_opts_from_qdict_1(const char *key, QObject *obj, void *opaque)
1181 {
1182     OptsFromQDictState *state = opaque;
1183     char buf[32];
1184     const char *value;
1185     int n;
1186
1187     if (!strcmp(key, "id") || *state->errp) {
1188         return;
1189     }
1190
1191     switch (qobject_type(obj)) {
1192     case QTYPE_QSTRING:
1193         value = qstring_get_str(qobject_to_qstring(obj));
1194         break;
1195     case QTYPE_QINT:
1196         n = snprintf(buf, sizeof(buf), "%" PRId64,
1197                      qint_get_int(qobject_to_qint(obj)));
1198         assert(n < sizeof(buf));
1199         value = buf;
1200         break;
1201     case QTYPE_QFLOAT:
1202         n = snprintf(buf, sizeof(buf), "%.17g",
1203                      qfloat_get_double(qobject_to_qfloat(obj)));
1204         assert(n < sizeof(buf));
1205         value = buf;
1206         break;
1207     case QTYPE_QBOOL:
1208         pstrcpy(buf, sizeof(buf),
1209                 qbool_get_int(qobject_to_qbool(obj)) ? "on" : "off");
1210         value = buf;
1211         break;
1212     default:
1213         return;
1214     }
1215
1216     qemu_opt_set_err(state->opts, key, value, state->errp);
1217 }
1218
1219 /*
1220  * Create QemuOpts from a QDict.
1221  * Use value of key "id" as ID if it exists and is a QString.
1222  * Only QStrings, QInts, QFloats and QBools are copied.  Entries with
1223  * other types are silently ignored.
1224  */
1225 QemuOpts *qemu_opts_from_qdict(QemuOptsList *list, const QDict *qdict,
1226                                Error **errp)
1227 {
1228     OptsFromQDictState state;
1229     Error *local_err = NULL;
1230     QemuOpts *opts;
1231
1232     opts = qemu_opts_create(list, qdict_get_try_str(qdict, "id"), 1,
1233                             &local_err);
1234     if (local_err) {
1235         error_propagate(errp, local_err);
1236         return NULL;
1237     }
1238
1239     assert(opts != NULL);
1240
1241     state.errp = &local_err;
1242     state.opts = opts;
1243     qdict_iter(qdict, qemu_opts_from_qdict_1, &state);
1244     if (local_err) {
1245         error_propagate(errp, local_err);
1246         qemu_opts_del(opts);
1247         return NULL;
1248     }
1249
1250     return opts;
1251 }
1252
1253 /*
1254  * Adds all QDict entries to the QemuOpts that can be added and removes them
1255  * from the QDict. When this function returns, the QDict contains only those
1256  * entries that couldn't be added to the QemuOpts.
1257  */
1258 void qemu_opts_absorb_qdict(QemuOpts *opts, QDict *qdict, Error **errp)
1259 {
1260     const QDictEntry *entry, *next;
1261
1262     entry = qdict_first(qdict);
1263
1264     while (entry != NULL) {
1265         Error *local_err = NULL;
1266         OptsFromQDictState state = {
1267             .errp = &local_err,
1268             .opts = opts,
1269         };
1270
1271         next = qdict_next(qdict, entry);
1272
1273         if (find_desc_by_name(opts->list->desc, entry->key)) {
1274             qemu_opts_from_qdict_1(entry->key, entry->value, &state);
1275             if (local_err) {
1276                 error_propagate(errp, local_err);
1277                 return;
1278             } else {
1279                 qdict_del(qdict, entry->key);
1280             }
1281         }
1282
1283         entry = next;
1284     }
1285 }
1286
1287 /*
1288  * Convert from QemuOpts to QDict.
1289  * The QDict values are of type QString.
1290  * TODO We'll want to use types appropriate for opt->desc->type, but
1291  * this is enough for now.
1292  */
1293 QDict *qemu_opts_to_qdict(QemuOpts *opts, QDict *qdict)
1294 {
1295     QemuOpt *opt;
1296     QObject *val;
1297
1298     if (!qdict) {
1299         qdict = qdict_new();
1300     }
1301     if (opts->id) {
1302         qdict_put(qdict, "id", qstring_from_str(opts->id));
1303     }
1304     QTAILQ_FOREACH(opt, &opts->head, next) {
1305         val = QOBJECT(qstring_from_str(opt->str));
1306         qdict_put_obj(qdict, opt->name, val);
1307     }
1308     return qdict;
1309 }
1310
1311 /* Validate parsed opts against descriptions where no
1312  * descriptions were provided in the QemuOptsList.
1313  */
1314 void qemu_opts_validate(QemuOpts *opts, const QemuOptDesc *desc, Error **errp)
1315 {
1316     QemuOpt *opt;
1317     Error *local_err = NULL;
1318
1319     assert(opts_accepts_any(opts));
1320
1321     QTAILQ_FOREACH(opt, &opts->head, next) {
1322         opt->desc = find_desc_by_name(desc, opt->name);
1323         if (!opt->desc) {
1324             error_set(errp, QERR_INVALID_PARAMETER, opt->name);
1325             return;
1326         }
1327
1328         qemu_opt_parse(opt, &local_err);
1329         if (local_err) {
1330             error_propagate(errp, local_err);
1331             return;
1332         }
1333     }
1334 }
1335
1336 int qemu_opts_foreach(QemuOptsList *list, qemu_opts_loopfunc func, void *opaque,
1337                       int abort_on_failure)
1338 {
1339     Location loc;
1340     QemuOpts *opts;
1341     int rc = 0;
1342
1343     loc_push_none(&loc);
1344     QTAILQ_FOREACH(opts, &list->head, next) {
1345         loc_restore(&opts->loc);
1346         rc |= func(opts, opaque);
1347         if (abort_on_failure  &&  rc != 0)
1348             break;
1349     }
1350     loc_pop(&loc);
1351     return rc;
1352 }
1353
1354 static size_t count_opts_list(QemuOptsList *list)
1355 {
1356     QemuOptDesc *desc = NULL;
1357     size_t num_opts = 0;
1358
1359     if (!list) {
1360         return 0;
1361     }
1362
1363     desc = list->desc;
1364     while (desc && desc->name) {
1365         num_opts++;
1366         desc++;
1367     }
1368
1369     return num_opts;
1370 }
1371
1372 /* Convert QEMUOptionParameter to QemuOpts
1373  * FIXME: this function will be removed after all drivers
1374  * switch to QemuOpts
1375  */
1376 QemuOptsList *params_to_opts(QEMUOptionParameter *list)
1377 {
1378     QemuOptsList *opts = NULL;
1379     size_t num_opts, i = 0;
1380
1381     if (!list) {
1382         return NULL;
1383     }
1384
1385     num_opts = count_option_parameters(list);
1386     opts = g_malloc0(sizeof(QemuOptsList) +
1387                      (num_opts + 1) * sizeof(QemuOptDesc));
1388     QTAILQ_INIT(&opts->head);
1389     /* (const char *) members will point to malloced space and need to free */
1390     opts->allocated = true;
1391
1392     while (list && list->name) {
1393         opts->desc[i].name = g_strdup(list->name);
1394         opts->desc[i].help = g_strdup(list->help);
1395         switch (list->type) {
1396         case OPT_FLAG:
1397             opts->desc[i].type = QEMU_OPT_BOOL;
1398             opts->desc[i].def_value_str =
1399                 g_strdup(list->value.n ? "on" : "off");
1400             break;
1401
1402         case OPT_NUMBER:
1403             opts->desc[i].type = QEMU_OPT_NUMBER;
1404             if (list->value.n) {
1405                 opts->desc[i].def_value_str =
1406                     g_strdup_printf("%" PRIu64, list->value.n);
1407             }
1408             break;
1409
1410         case OPT_SIZE:
1411             opts->desc[i].type = QEMU_OPT_SIZE;
1412             if (list->value.n) {
1413                 opts->desc[i].def_value_str =
1414                     g_strdup_printf("%" PRIu64, list->value.n);
1415             }
1416             break;
1417
1418         case OPT_STRING:
1419             opts->desc[i].type = QEMU_OPT_STRING;
1420             opts->desc[i].def_value_str = g_strdup(list->value.s);
1421             break;
1422         }
1423
1424         i++;
1425         list++;
1426     }
1427
1428     return opts;
1429 }
1430
1431 /* convert QemuOpts to QEMUOptionParameter
1432  * Note: result QEMUOptionParameter has shorter lifetime than
1433  * input QemuOpts.
1434  * FIXME: this function will be removed after all drivers
1435  * switch to QemuOpts
1436  */
1437 QEMUOptionParameter *opts_to_params(QemuOpts *opts)
1438 {
1439     QEMUOptionParameter *dest = NULL;
1440     QemuOptDesc *desc;
1441     size_t num_opts, i = 0;
1442     const char *tmp;
1443
1444     if (!opts || !opts->list || !opts->list->desc) {
1445         return NULL;
1446     }
1447     assert(!opts_accepts_any(opts));
1448
1449     num_opts = count_opts_list(opts->list);
1450     dest = g_malloc0((num_opts + 1) * sizeof(QEMUOptionParameter));
1451
1452     desc = opts->list->desc;
1453     while (desc && desc->name) {
1454         dest[i].name = desc->name;
1455         dest[i].help = desc->help;
1456         dest[i].assigned = qemu_opt_find(opts, desc->name) ? true : false;
1457         switch (desc->type) {
1458         case QEMU_OPT_STRING:
1459             dest[i].type = OPT_STRING;
1460             tmp = qemu_opt_get(opts, desc->name);
1461             dest[i].value.s = g_strdup(tmp);
1462             break;
1463
1464         case QEMU_OPT_BOOL:
1465             dest[i].type = OPT_FLAG;
1466             dest[i].value.n = qemu_opt_get_bool(opts, desc->name, 0) ? 1 : 0;
1467             break;
1468
1469         case QEMU_OPT_NUMBER:
1470             dest[i].type = OPT_NUMBER;
1471             dest[i].value.n = qemu_opt_get_number(opts, desc->name, 0);
1472             break;
1473
1474         case QEMU_OPT_SIZE:
1475             dest[i].type = OPT_SIZE;
1476             dest[i].value.n = qemu_opt_get_size(opts, desc->name, 0);
1477             break;
1478         }
1479
1480         i++;
1481         desc++;
1482     }
1483
1484     return dest;
1485 }
1486
1487 void qemu_opts_free(QemuOptsList *list)
1488 {
1489     /* List members point to new malloced space and need to be freed.
1490      * FIXME:
1491      * Introduced for QEMUOptionParamter->QemuOpts conversion.
1492      * Will remove after all drivers switch to QemuOpts.
1493      */
1494     if (list && list->allocated) {
1495         QemuOptDesc *desc = list->desc;
1496         while (desc && desc->name) {
1497             g_free((char *)desc->name);
1498             g_free((char *)desc->help);
1499             g_free((char *)desc->def_value_str);
1500             desc++;
1501         }
1502     }
1503
1504     g_free(list);
1505 }
1506
1507 /* Realloc dst option list and append options either from an option list (list)
1508  * or a QEMUOptionParameter (param) to it. dst could be NULL or a malloced list.
1509  * FIXME: will remove QEMUOptionParameter after all drivers switch to QemuOpts.
1510  */
1511 QemuOptsList *qemu_opts_append(QemuOptsList *dst,
1512                                QemuOptsList *list,
1513                                QEMUOptionParameter *param)
1514 {
1515     size_t num_opts, num_dst_opts;
1516     QemuOptDesc *desc;
1517     bool need_init = false;
1518
1519     assert(!(list && param));
1520     if (!param && !list) {
1521         return dst;
1522     }
1523
1524     if (param) {
1525         list = params_to_opts(param);
1526     }
1527
1528     /* If dst is NULL, after realloc, some area of dst should be initialized
1529      * before adding options to it.
1530      */
1531     if (!dst) {
1532         need_init = true;
1533     }
1534
1535     num_opts = count_opts_list(dst);
1536     num_dst_opts = num_opts;
1537     num_opts += count_opts_list(list);
1538     dst = g_realloc(dst, sizeof(QemuOptsList) +
1539                     (num_opts + 1) * sizeof(QemuOptDesc));
1540     if (need_init) {
1541         dst->name = NULL;
1542         dst->implied_opt_name = NULL;
1543         QTAILQ_INIT(&dst->head);
1544         dst->allocated = true;
1545         dst->merge_lists = false;
1546     }
1547     dst->desc[num_dst_opts].name = NULL;
1548
1549     /* (const char *) members of result dst are malloced, need free. */
1550     assert(dst->allocated);
1551     /* append list->desc to dst->desc */
1552     if (list) {
1553         desc = list->desc;
1554         while (desc && desc->name) {
1555             if (find_desc_by_name(dst->desc, desc->name) == NULL) {
1556                 dst->desc[num_dst_opts].name = g_strdup(desc->name);
1557                 dst->desc[num_dst_opts].type = desc->type;
1558                 dst->desc[num_dst_opts].help = g_strdup(desc->help);
1559                 dst->desc[num_dst_opts].def_value_str =
1560                                          g_strdup(desc->def_value_str);
1561                 num_dst_opts++;
1562                 dst->desc[num_dst_opts].name = NULL;
1563             }
1564             desc++;
1565         }
1566     }
1567
1568     if (param) {
1569         qemu_opts_free(list);
1570     }
1571     return dst;
1572 }