qemu

qemu-option.c (33144B)

---

 /*
  * Commandline option parsing functions
  *
  * Copyright (c) 2003-2008 Fabrice Bellard
  * Copyright (c) 2009 Kevin Wolf <kwolf@redhat.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
 
 #include "qemu/osdep.h"
 
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "qapi/qmp/qbool.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qnum.h"
 #include "qapi/qmp/qstring.h"
 #include "qapi/qmp/qerror.h"
 #include "qemu/option_int.h"
 #include "qemu/cutils.h"
 #include "qemu/id.h"
 #include "qemu/help_option.h"
 
 /*
  * Extracts the name of an option from the parameter string (@p points at the
  * first byte of the option name)
  *
  * The option name is @len characters long and is copied into @option. The
  * caller is responsible for free'ing @option when no longer required.
  *
  * The return value is the position of the delimiter/zero byte after the option
  * name in @p.
  */
 static const char *get_opt_name(const char *p, char **option, size_t len)
 {
     *option = g_strndup(p, len);
     return p + len;
 }
 
 /*
  * Extracts the value of an option from the parameter string p (p points at the
  * first byte of the option value)
  *
  * This function is comparable to get_opt_name with the difference that the
  * delimiter is fixed to be comma which starts a new option. To specify an
  * option value that contains commas, double each comma.
  */
 const char *get_opt_value(const char *p, char **value)
 {
     size_t capacity = 0, length;
     const char *offset;
 
     *value = NULL;
     while (1) {
         offset = qemu_strchrnul(p, ',');
         length = offset - p;
         if (*offset != '\0' && *(offset + 1) == ',') {
             length++;
         }
         *value = g_renew(char, *value, capacity + length + 1);
         strncpy(*value + capacity, p, length);
         (*value)[capacity + length] = '\0';
         capacity += length;
         if (*offset == '\0' ||
             *(offset + 1) != ',') {
             break;
         }
 
         p += (offset - p) + 2;
     }
 
     return offset;
 }
 
 static bool parse_option_number(const char *name, const char *value,
                                 uint64_t *ret, Error **errp)
 {
     uint64_t number;
     int err;
 
     err = qemu_strtou64(value, NULL, 0, &number);
     if (err == -ERANGE) {
         error_setg(errp, "Value '%s' is too large for parameter '%s'",
                    value, name);
         return false;
     }
     if (err) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, name, "a number");
         return false;
     }
     *ret = number;
     return true;
 }
 
 static const QemuOptDesc *find_desc_by_name(const QemuOptDesc *desc,
                                             const char *name)
 {
     int i;
 
     for (i = 0; desc[i].name != NULL; i++) {
         if (strcmp(desc[i].name, name) == 0) {
             return &desc[i];
         }
     }
 
     return NULL;
 }
 
 static const char *find_default_by_name(QemuOpts *opts, const char *name)
 {
     const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
 
     return desc ? desc->def_value_str : NULL;
 }
 
 bool parse_option_size(const char *name, const char *value,
                        uint64_t *ret, Error **errp)
 {
     uint64_t size;
     int err;
 
     err = qemu_strtosz(value, NULL, &size);
     if (err == -ERANGE) {
         error_setg(errp, "Value '%s' is out of range for parameter '%s'",
                    value, name);
         return false;
     }
     if (err) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, name,
                    "a non-negative number below 2^64");
         error_append_hint(errp, "Optional suffix k, M, G, T, P or E means"
                           " kilo-, mega-, giga-, tera-, peta-\n"
                           "and exabytes, respectively.\n");
         return false;
     }
     *ret = size;
     return true;
 }
 
 static const char *opt_type_to_string(enum QemuOptType type)
 {
     switch (type) {
     case QEMU_OPT_STRING:
         return "str";
     case QEMU_OPT_BOOL:
         return "bool (on/off)";
     case QEMU_OPT_NUMBER:
         return "num";
     case QEMU_OPT_SIZE:
         return "size";
     }
 
     g_assert_not_reached();
 }
 
 /**
  * Print the list of options available in the given list.  If
  * @print_caption is true, a caption (including the list name, if it
  * exists) is printed.  The options itself will be indented, so
  * @print_caption should only be set to false if the caller prints its
  * own custom caption (so that the indentation makes sense).
  */
 void qemu_opts_print_help(QemuOptsList *list, bool print_caption)
 {
     QemuOptDesc *desc;
     int i;
     GPtrArray *array = g_ptr_array_new();
 
     assert(list);
     desc = list->desc;
     while (desc && desc->name) {
         GString *str = g_string_new(NULL);
         g_string_append_printf(str, "  %s=<%s>", desc->name,
                                opt_type_to_string(desc->type));
         if (desc->help) {
             if (str->len < 24) {
                 g_string_append_printf(str, "%*s", 24 - (int)str->len, "");
             }
             g_string_append_printf(str, " - %s", desc->help);
         }
         g_ptr_array_add(array, g_string_free(str, false));
         desc++;
     }
 
     g_ptr_array_sort(array, (GCompareFunc)qemu_pstrcmp0);
     if (print_caption && array->len > 0) {
         if (list->name) {
             printf("%s options:\n", list->name);
         } else {
             printf("Options:\n");
         }
     } else if (array->len == 0) {
         if (list->name) {
             printf("There are no options for %s.\n", list->name);
         } else {
             printf("No options available.\n");
         }
     }
     for (i = 0; i < array->len; i++) {
         printf("%s\n", (char *)array->pdata[i]);
     }
     g_ptr_array_set_free_func(array, g_free);
     g_ptr_array_free(array, true);
 
 }
 /* ------------------------------------------------------------------ */
 
 QemuOpt *qemu_opt_find(QemuOpts *opts, const char *name)
 {
     QemuOpt *opt;
 
     QTAILQ_FOREACH_REVERSE(opt, &opts->head, next) {
         if (strcmp(opt->name, name) != 0)
             continue;
         return opt;
     }
     return NULL;
 }
 
 static void qemu_opt_del(QemuOpt *opt)
 {
     QTAILQ_REMOVE(&opt->opts->head, opt, next);
     g_free(opt->name);
     g_free(opt->str);
     g_free(opt);
 }
 
 /* qemu_opt_set allows many settings for the same option.
  * This function deletes all settings for an option.
  */
 static void qemu_opt_del_all(QemuOpts *opts, const char *name)
 {
     QemuOpt *opt, *next_opt;
 
     QTAILQ_FOREACH_SAFE(opt, &opts->head, next, next_opt) {
         if (!strcmp(opt->name, name)) {
             qemu_opt_del(opt);
         }
     }
 }
 
 const char *qemu_opt_get(QemuOpts *opts, const char *name)
 {
     QemuOpt *opt;
 
     if (opts == NULL) {
         return NULL;
     }
 
     opt = qemu_opt_find(opts, name);
     if (!opt) {
         return find_default_by_name(opts, name);
     }
 
     return opt->str;
 }
 
 void qemu_opt_iter_init(QemuOptsIter *iter, QemuOpts *opts, const char *name)
 {
     iter->opts = opts;
     iter->opt = QTAILQ_FIRST(&opts->head);
     iter->name = name;
 }
 
 const char *qemu_opt_iter_next(QemuOptsIter *iter)
 {
     QemuOpt *ret = iter->opt;
     if (iter->name) {
         while (ret && !g_str_equal(iter->name, ret->name)) {
             ret = QTAILQ_NEXT(ret, next);
         }
     }
     iter->opt = ret ? QTAILQ_NEXT(ret, next) : NULL;
     return ret ? ret->str : NULL;
 }
 
 /* Get a known option (or its default) and remove it from the list
  * all in one action. Return a malloced string of the option value.
  * Result must be freed by caller with g_free().
  */
 char *qemu_opt_get_del(QemuOpts *opts, const char *name)
 {
     QemuOpt *opt;
     char *str;
 
     if (opts == NULL) {
         return NULL;
     }
 
     opt = qemu_opt_find(opts, name);
     if (!opt) {
         return g_strdup(find_default_by_name(opts, name));
     }
     str = opt->str;
     opt->str = NULL;
     qemu_opt_del_all(opts, name);
     return str;
 }
 
 bool qemu_opt_has_help_opt(QemuOpts *opts)
 {
     QemuOpt *opt;
 
     QTAILQ_FOREACH_REVERSE(opt, &opts->head, next) {
         if (is_help_option(opt->name)) {
             return true;
         }
     }
     return false;
 }
 
 static bool qemu_opt_get_bool_helper(QemuOpts *opts, const char *name,
                                      bool defval, bool del)
 {
     QemuOpt *opt;
     const char *def_val;
     bool ret = defval;
 
     if (opts == NULL) {
         return ret;
     }
 
     opt = qemu_opt_find(opts, name);
     if (opt == NULL) {
         def_val = find_default_by_name(opts, name);
         if (def_val) {
             qapi_bool_parse(name, def_val, &ret, &error_abort);
         }
         return ret;
     }
     assert(opt->desc && opt->desc->type == QEMU_OPT_BOOL);
     ret = opt->value.boolean;
     if (del) {
         qemu_opt_del_all(opts, name);
     }
     return ret;
 }
 
 bool qemu_opt_get_bool(QemuOpts *opts, const char *name, bool defval)
 {
     return qemu_opt_get_bool_helper(opts, name, defval, false);
 }
 
 bool qemu_opt_get_bool_del(QemuOpts *opts, const char *name, bool defval)
 {
     return qemu_opt_get_bool_helper(opts, name, defval, true);
 }
 
 static uint64_t qemu_opt_get_number_helper(QemuOpts *opts, const char *name,
                                            uint64_t defval, bool del)
 {
     QemuOpt *opt;
     const char *def_val;
     uint64_t ret = defval;
 
     if (opts == NULL) {
         return ret;
     }
 
     opt = qemu_opt_find(opts, name);
     if (opt == NULL) {
         def_val = find_default_by_name(opts, name);
         if (def_val) {
             parse_option_number(name, def_val, &ret, &error_abort);
         }
         return ret;
     }
     assert(opt->desc && opt->desc->type == QEMU_OPT_NUMBER);
     ret = opt->value.uint;
     if (del) {
         qemu_opt_del_all(opts, name);
     }
     return ret;
 }
 
 uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t defval)
 {
     return qemu_opt_get_number_helper(opts, name, defval, false);
 }
 
 uint64_t qemu_opt_get_number_del(QemuOpts *opts, const char *name,
                                  uint64_t defval)
 {
     return qemu_opt_get_number_helper(opts, name, defval, true);
 }
 
 static uint64_t qemu_opt_get_size_helper(QemuOpts *opts, const char *name,
                                          uint64_t defval, bool del)
 {
     QemuOpt *opt;
     const char *def_val;
     uint64_t ret = defval;
 
     if (opts == NULL) {
         return ret;
     }
 
     opt = qemu_opt_find(opts, name);
     if (opt == NULL) {
         def_val = find_default_by_name(opts, name);
         if (def_val) {
             parse_option_size(name, def_val, &ret, &error_abort);
         }
         return ret;
     }
     assert(opt->desc && opt->desc->type == QEMU_OPT_SIZE);
     ret = opt->value.uint;
     if (del) {
         qemu_opt_del_all(opts, name);
     }
     return ret;
 }
 
 uint64_t qemu_opt_get_size(QemuOpts *opts, const char *name, uint64_t defval)
 {
     return qemu_opt_get_size_helper(opts, name, defval, false);
 }
 
 uint64_t qemu_opt_get_size_del(QemuOpts *opts, const char *name,
                                uint64_t defval)
 {
     return qemu_opt_get_size_helper(opts, name, defval, true);
 }
 
 static bool qemu_opt_parse(QemuOpt *opt, Error **errp)
 {
     if (opt->desc == NULL)
         return true;
 
     switch (opt->desc->type) {
     case QEMU_OPT_STRING:
         /* nothing */
         return true;
     case QEMU_OPT_BOOL:
         return qapi_bool_parse(opt->name, opt->str, &opt->value.boolean, errp);
     case QEMU_OPT_NUMBER:
         return parse_option_number(opt->name, opt->str, &opt->value.uint,
                                    errp);
     case QEMU_OPT_SIZE:
         return parse_option_size(opt->name, opt->str, &opt->value.uint,
                                  errp);
     default:
         abort();
     }
 }
 
 static bool opts_accepts_any(const QemuOptsList *list)
 {
     return list->desc[0].name == NULL;
 }
 
 int qemu_opt_unset(QemuOpts *opts, const char *name)
 {
     QemuOpt *opt = qemu_opt_find(opts, name);
 
     assert(opts_accepts_any(opts->list));
 
     if (opt == NULL) {
         return -1;
     } else {
         qemu_opt_del(opt);
         return 0;
     }
 }
 
 static QemuOpt *opt_create(QemuOpts *opts, const char *name, char *value)
 {
     QemuOpt *opt = g_malloc0(sizeof(*opt));
 
     opt->name = g_strdup(name);
     opt->str = value;
     opt->opts = opts;
     QTAILQ_INSERT_TAIL(&opts->head, opt, next);
 
     return opt;
 }
 
 static bool opt_validate(QemuOpt *opt, Error **errp)
 {
     const QemuOptDesc *desc;
     const QemuOptsList *list = opt->opts->list;
 
     desc = find_desc_by_name(list->desc, opt->name);
     if (!desc && !opts_accepts_any(list)) {
         error_setg(errp, QERR_INVALID_PARAMETER, opt->name);
         return false;
     }
 
     opt->desc = desc;
     if (!qemu_opt_parse(opt, errp)) {
         return false;
     }
 
     return true;
 }
 
 bool qemu_opt_set(QemuOpts *opts, const char *name, const char *value,
                   Error **errp)
 {
     QemuOpt *opt = opt_create(opts, name, g_strdup(value));
 
     if (!opt_validate(opt, errp)) {
         qemu_opt_del(opt);
         return false;
     }
     return true;
 }
 
 bool qemu_opt_set_bool(QemuOpts *opts, const char *name, bool val,
                        Error **errp)
 {
     QemuOpt *opt;
     const QemuOptDesc *desc;
     const QemuOptsList *list = opts->list;
 
     desc = find_desc_by_name(list->desc, name);
     if (!desc && !opts_accepts_any(list)) {
         error_setg(errp, QERR_INVALID_PARAMETER, name);
         return false;
     }
 
     opt = g_malloc0(sizeof(*opt));
     opt->name = g_strdup(name);
     opt->opts = opts;
     opt->desc = desc;
     opt->value.boolean = !!val;
     opt->str = g_strdup(val ? "on" : "off");
     QTAILQ_INSERT_TAIL(&opts->head, opt, next);
     return true;
 }
 
 bool qemu_opt_set_number(QemuOpts *opts, const char *name, int64_t val,
                          Error **errp)
 {
     QemuOpt *opt;
     const QemuOptDesc *desc;
     const QemuOptsList *list = opts->list;
 
     desc = find_desc_by_name(list->desc, name);
     if (!desc && !opts_accepts_any(list)) {
         error_setg(errp, QERR_INVALID_PARAMETER, name);
         return false;
     }
 
     opt = g_malloc0(sizeof(*opt));
     opt->name = g_strdup(name);
     opt->opts = opts;
     opt->desc = desc;
     opt->value.uint = val;
     opt->str = g_strdup_printf("%" PRId64, val);
     QTAILQ_INSERT_TAIL(&opts->head, opt, next);
     return true;
 }
 
 /**
  * For each member of @opts, call @func(@opaque, name, value, @errp).
  * @func() may store an Error through @errp, but must return non-zero then.
  * When @func() returns non-zero, break the loop and return that value.
  * Return zero when the loop completes.
  */
 int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
                      Error **errp)
 {
     QemuOpt *opt;
     int rc;
 
     QTAILQ_FOREACH(opt, &opts->head, next) {
         rc = func(opaque, opt->name, opt->str, errp);
         if (rc) {
             return rc;
         }
         assert(!errp || !*errp);
     }
     return 0;
 }
 
 QemuOpts *qemu_opts_find(QemuOptsList *list, const char *id)
 {
     QemuOpts *opts;
 
     QTAILQ_FOREACH(opts, &list->head, next) {
         if (!opts->id && !id) {
             return opts;
         }
         if (opts->id && id && !strcmp(opts->id, id)) {
             return opts;
         }
     }
     return NULL;
 }
 
 QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id,
                            int fail_if_exists, Error **errp)
 {
     QemuOpts *opts = NULL;
 
     if (list->merge_lists) {
         if (id) {
             error_setg(errp, QERR_INVALID_PARAMETER, "id");
             return NULL;
         }
         opts = qemu_opts_find(list, NULL);
         if (opts) {
             return opts;
         }
     } else if (id) {
         assert(fail_if_exists);
         if (!id_wellformed(id)) {
             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "id",
                        "an identifier");
             error_append_hint(errp, "Identifiers consist of letters, digits, "
                               "'-', '.', '_', starting with a letter.\n");
             return NULL;
         }
         opts = qemu_opts_find(list, id);
         if (opts != NULL) {
             error_setg(errp, "Duplicate ID '%s' for %s", id, list->name);
             return NULL;
         }
     }
     opts = g_malloc0(sizeof(*opts));
     opts->id = g_strdup(id);
     opts->list = list;
     loc_save(&opts->loc);
     QTAILQ_INIT(&opts->head);
     QTAILQ_INSERT_TAIL(&list->head, opts, next);
     return opts;
 }
 
 void qemu_opts_reset(QemuOptsList *list)
 {
     QemuOpts *opts, *next_opts;
 
     QTAILQ_FOREACH_SAFE(opts, &list->head, next, next_opts) {
         qemu_opts_del(opts);
     }
 }
 
 void qemu_opts_loc_restore(QemuOpts *opts)
 {
     loc_restore(&opts->loc);
 }
 
 const char *qemu_opts_id(QemuOpts *opts)
 {
     return opts->id;
 }
 
 /* The id string will be g_free()d by qemu_opts_del */
 void qemu_opts_set_id(QemuOpts *opts, char *id)
 {
     opts->id = id;
 }
 
 void qemu_opts_del(QemuOpts *opts)
 {
     QemuOpt *opt;
 
     if (opts == NULL) {
         return;
     }
 
     for (;;) {
         opt = QTAILQ_FIRST(&opts->head);
         if (opt == NULL)
             break;
         qemu_opt_del(opt);
     }
     QTAILQ_REMOVE(&opts->list->head, opts, next);
     g_free(opts->id);
     g_free(opts);
 }
 
 /* print value, escaping any commas in value */
 static void escaped_print(const char *value)
 {
     const char *ptr;
 
     for (ptr = value; *ptr; ++ptr) {
         if (*ptr == ',') {
             putchar(',');
         }
         putchar(*ptr);
     }
 }
 
 void qemu_opts_print(QemuOpts *opts, const char *separator)
 {
     QemuOpt *opt;
     QemuOptDesc *desc = opts->list->desc;
     const char *sep = "";
 
     if (opts->id) {
         printf("id=%s", opts->id); /* passed id_wellformed -> no commas */
         sep = separator;
     }
 
     if (desc[0].name == NULL) {
         QTAILQ_FOREACH(opt, &opts->head, next) {
             printf("%s%s=", sep, opt->name);
             escaped_print(opt->str);
             sep = separator;
         }
         return;
     }
     for (; desc && desc->name; desc++) {
         const char *value;
         opt = qemu_opt_find(opts, desc->name);
 
         value = opt ? opt->str : desc->def_value_str;
         if (!value) {
             continue;
         }
         if (desc->type == QEMU_OPT_STRING) {
             printf("%s%s=", sep, desc->name);
             escaped_print(value);
         } else if ((desc->type == QEMU_OPT_SIZE ||
                     desc->type == QEMU_OPT_NUMBER) && opt) {
             printf("%s%s=%" PRId64, sep, desc->name, opt->value.uint);
         } else {
             printf("%s%s=%s", sep, desc->name, value);
         }
         sep = separator;
     }
 }
 
 static const char *get_opt_name_value(const char *params,
                                       const char *firstname,
                                       bool warn_on_flag,
                                       bool *help_wanted,
                                       char **name, char **value)
 {
     const char *p;
     const char *prefix = "";
     size_t len;
     bool is_help = false;
 
     len = strcspn(params, "=,");
     if (params[len] != '=') {
         /* found "foo,more" */
         if (firstname) {
             /* implicitly named first option */
             *name = g_strdup(firstname);
             p = get_opt_value(params, value);
         } else {
             /* option without value, must be a flag */
             p = get_opt_name(params, name, len);
             if (strncmp(*name, "no", 2) == 0) {
                 memmove(*name, *name + 2, strlen(*name + 2) + 1);
                 *value = g_strdup("off");
                 prefix = "no";
             } else {
                 *value = g_strdup("on");
                 is_help = is_help_option(*name);
             }
             if (!is_help && warn_on_flag) {
                 warn_report("short-form boolean option '%s%s' deprecated", prefix, *name);
                 if (g_str_equal(*name, "delay")) {
                     error_printf("Please use nodelay=%s instead\n", prefix[0] ? "on" : "off");
                 } else {
                     error_printf("Please use %s=%s instead\n", *name, *value);
                 }
             }
         }
     } else {
         /* found "foo=bar,more" */
         p = get_opt_name(params, name, len);
         assert(*p == '=');
         p++;
         p = get_opt_value(p, value);
     }
 
     assert(!*p || *p == ',');
     if (help_wanted && is_help) {
         *help_wanted = true;
     }
     if (*p == ',') {
         p++;
     }
     return p;
 }
 
 static bool opts_do_parse(QemuOpts *opts, const char *params,
                           const char *firstname,
                           bool warn_on_flag, bool *help_wanted, Error **errp)
 {
     char *option, *value;
     const char *p;
     QemuOpt *opt;
 
     for (p = params; *p;) {
         p = get_opt_name_value(p, firstname, warn_on_flag, help_wanted, &option, &value);
         if (help_wanted && *help_wanted) {
             g_free(option);
             g_free(value);
             return false;
         }
         firstname = NULL;
 
         if (!strcmp(option, "id")) {
             g_free(option);
             g_free(value);
             continue;
         }
 
         opt = opt_create(opts, option, value);
         g_free(option);
         if (!opt_validate(opt, errp)) {
             qemu_opt_del(opt);
             return false;
         }
     }
 
     return true;
 }
 
 static char *opts_parse_id(const char *params)
 {
     const char *p;
     char *name, *value;
 
     for (p = params; *p;) {
         p = get_opt_name_value(p, NULL, false, NULL, &name, &value);
         if (!strcmp(name, "id")) {
             g_free(name);
             return value;
         }
         g_free(name);
         g_free(value);
     }
 
     return NULL;
 }
 
 bool has_help_option(const char *params)
 {
     const char *p;
     char *name, *value;
     bool ret = false;
 
     for (p = params; *p;) {
         p = get_opt_name_value(p, NULL, false, &ret, &name, &value);
         g_free(name);
         g_free(value);
         if (ret) {
             return true;
         }
     }
 
     return false;
 }
 
 /**
  * Store options parsed from @params into @opts.
  * If @firstname is non-null, the first key=value in @params may omit
  * key=, and is treated as if key was @firstname.
  * On error, store an error object through @errp if non-null.
  */
 bool qemu_opts_do_parse(QemuOpts *opts, const char *params,
                        const char *firstname, Error **errp)
 {
     return opts_do_parse(opts, params, firstname, false, NULL, errp);
 }
 
 static QemuOpts *opts_parse(QemuOptsList *list, const char *params,
                             bool permit_abbrev,
                             bool warn_on_flag, bool *help_wanted, Error **errp)
 {
     const char *firstname;
     char *id = opts_parse_id(params);
     QemuOpts *opts;
 
     assert(!permit_abbrev || list->implied_opt_name);
     firstname = permit_abbrev ? list->implied_opt_name : NULL;
 
     opts = qemu_opts_create(list, id, !list->merge_lists, errp);
     g_free(id);
     if (opts == NULL) {
         return NULL;
     }
 
     if (!opts_do_parse(opts, params, firstname,
                        warn_on_flag, help_wanted, errp)) {
         qemu_opts_del(opts);
         return NULL;
     }
 
     return opts;
 }
 
 /**
  * Create a QemuOpts in @list and with options parsed from @params.
  * If @permit_abbrev, the first key=value in @params may omit key=,
  * and is treated as if key was @list->implied_opt_name.
  * On error, store an error object through @errp if non-null.
  * Return the new QemuOpts on success, null pointer on error.
  */
 QemuOpts *qemu_opts_parse(QemuOptsList *list, const char *params,
                           bool permit_abbrev, Error **errp)
 {
     return opts_parse(list, params, permit_abbrev, false, NULL, errp);
 }
 
 /**
  * Create a QemuOpts in @list and with options parsed from @params.
  * If @permit_abbrev, the first key=value in @params may omit key=,
  * and is treated as if key was @list->implied_opt_name.
  * Report errors with error_report_err().  This is inappropriate in
  * QMP context.  Do not use this function there!
  * Return the new QemuOpts on success, null pointer on error.
  */
 QemuOpts *qemu_opts_parse_noisily(QemuOptsList *list, const char *params,
                                   bool permit_abbrev)
 {
     Error *err = NULL;
     QemuOpts *opts;
     bool help_wanted = false;
 
     opts = opts_parse(list, params, permit_abbrev, true,
                       opts_accepts_any(list) ? NULL : &help_wanted,
                       &err);
     if (!opts) {
         assert(!!err + !!help_wanted == 1);
         if (help_wanted) {
             qemu_opts_print_help(list, true);
         } else {
             error_report_err(err);
         }
     }
     return opts;
 }
 
 static bool qemu_opts_from_qdict_entry(QemuOpts *opts,
                                        const QDictEntry *entry,
                                        Error **errp)
 {
     const char *key = qdict_entry_key(entry);
     QObject *obj = qdict_entry_value(entry);
     char buf[32];
     g_autofree char *tmp = NULL;
     const char *value;
 
     if (!strcmp(key, "id")) {
         return true;
     }
 
     switch (qobject_type(obj)) {
     case QTYPE_QSTRING:
         value = qstring_get_str(qobject_to(QString, obj));
         break;
     case QTYPE_QNUM:
         tmp = qnum_to_string(qobject_to(QNum, obj));
         value = tmp;
         break;
     case QTYPE_QBOOL:
         pstrcpy(buf, sizeof(buf),
                 qbool_get_bool(qobject_to(QBool, obj)) ? "on" : "off");
         value = buf;
         break;
     default:
         return true;
     }
 
     return qemu_opt_set(opts, key, value, errp);
 }
 
 /*
  * Create QemuOpts from a QDict.
  * Use value of key "id" as ID if it exists and is a QString.  Only
  * QStrings, QNums and QBools are copied.  Entries with other types
  * are silently ignored.
  */
 QemuOpts *qemu_opts_from_qdict(QemuOptsList *list, const QDict *qdict,
                                Error **errp)
 {
     QemuOpts *opts;
     const QDictEntry *entry;
 
     opts = qemu_opts_create(list, qdict_get_try_str(qdict, "id"), 1, errp);
     if (!opts) {
         return NULL;
     }
 
     for (entry = qdict_first(qdict);
          entry;
          entry = qdict_next(qdict, entry)) {
         if (!qemu_opts_from_qdict_entry(opts, entry, errp)) {
             qemu_opts_del(opts);
             return NULL;
         }
     }
 
     return opts;
 }
 
 /*
  * Adds all QDict entries to the QemuOpts that can be added and removes them
  * from the QDict. When this function returns, the QDict contains only those
  * entries that couldn't be added to the QemuOpts.
  */
 bool qemu_opts_absorb_qdict(QemuOpts *opts, QDict *qdict, Error **errp)
 {
     const QDictEntry *entry, *next;
 
     entry = qdict_first(qdict);
 
     while (entry != NULL) {
         next = qdict_next(qdict, entry);
 
         if (opts_accepts_any(opts->list) ||
             find_desc_by_name(opts->list->desc, entry->key)) {
             if (!qemu_opts_from_qdict_entry(opts, entry, errp)) {
                 return false;
             }
             qdict_del(qdict, entry->key);
         }
 
         entry = next;
     }
 
     return true;
 }
 
 /*
  * Convert from QemuOpts to QDict. The QDict values are of type QString.
  *
  * If @list is given, only add those options to the QDict that are contained in
  * the list. If @del is true, any options added to the QDict are removed from
  * the QemuOpts, otherwise they remain there.
  *
  * If two options in @opts have the same name, they are processed in order
  * so that the last one wins (consistent with the reverse iteration in
  * qemu_opt_find()), but all of them are deleted if @del is true.
  *
  * TODO We'll want to use types appropriate for opt->desc->type, but
  * this is enough for now.
  */
 QDict *qemu_opts_to_qdict_filtered(QemuOpts *opts, QDict *qdict,
                                    QemuOptsList *list, bool del)
 {
     QemuOpt *opt, *next;
 
     if (!qdict) {
         qdict = qdict_new();
     }
     if (opts->id) {
         qdict_put_str(qdict, "id", opts->id);
     }
     QTAILQ_FOREACH_SAFE(opt, &opts->head, next, next) {
         if (list) {
             QemuOptDesc *desc;
             bool found = false;
             for (desc = list->desc; desc->name; desc++) {
                 if (!strcmp(desc->name, opt->name)) {
                     found = true;
                     break;
                 }
             }
             if (!found) {
                 continue;
             }
         }
         qdict_put_str(qdict, opt->name, opt->str);
         if (del) {
             qemu_opt_del(opt);
         }
     }
     return qdict;
 }
 
 /* Copy all options in a QemuOpts to the given QDict. See
  * qemu_opts_to_qdict_filtered() for details. */
 QDict *qemu_opts_to_qdict(QemuOpts *opts, QDict *qdict)
 {
     return qemu_opts_to_qdict_filtered(opts, qdict, NULL, false);
 }
 
 /* Validate parsed opts against descriptions where no
  * descriptions were provided in the QemuOptsList.
  */
 bool qemu_opts_validate(QemuOpts *opts, const QemuOptDesc *desc, Error **errp)
 {
     QemuOpt *opt;
 
     assert(opts_accepts_any(opts->list));
 
     QTAILQ_FOREACH(opt, &opts->head, next) {
         opt->desc = find_desc_by_name(desc, opt->name);
         if (!opt->desc) {
             error_setg(errp, QERR_INVALID_PARAMETER, opt->name);
             return false;
         }
 
         if (!qemu_opt_parse(opt, errp)) {
             return false;
         }
     }
 
     return true;
 }
 
 /**
  * For each member of @list, call @func(@opaque, member, @errp).
  * Call it with the current location temporarily set to the member's.
  * @func() may store an Error through @errp, but must return non-zero then.
  * When @func() returns non-zero, break the loop and return that value.
  * Return zero when the loop completes.
  */
 int qemu_opts_foreach(QemuOptsList *list, qemu_opts_loopfunc func,
                       void *opaque, Error **errp)
 {
     Location loc;
     QemuOpts *opts, *next;
     int rc = 0;
 
     loc_push_none(&loc);
     QTAILQ_FOREACH_SAFE(opts, &list->head, next, next) {
         loc_restore(&opts->loc);
         rc = func(opaque, opts, errp);
         if (rc) {
             break;
         }
         assert(!errp || !*errp);
     }
     loc_pop(&loc);
     return rc;
 }
 
 static size_t count_opts_list(QemuOptsList *list)
 {
     QemuOptDesc *desc = NULL;
     size_t num_opts = 0;
 
     if (!list) {
         return 0;
     }
 
     desc = list->desc;
     while (desc && desc->name) {
         num_opts++;
         desc++;
     }
 
     return num_opts;
 }
 
 void qemu_opts_free(QemuOptsList *list)
 {
     g_free(list);
 }
 
 /* Realloc dst option list and append options from an option list (list)
  * to it. dst could be NULL or a malloced list.
  * The lifetime of dst must be shorter than the input list because the
  * QemuOptDesc->name, ->help, and ->def_value_str strings are shared.
  */
 QemuOptsList *qemu_opts_append(QemuOptsList *dst,
                                QemuOptsList *list)
 {
     size_t num_opts, num_dst_opts;
     QemuOptDesc *desc;
     bool need_init = false;
     bool need_head_update;
 
     if (!list) {
         return dst;
     }
 
     /* If dst is NULL, after realloc, some area of dst should be initialized
      * before adding options to it.
      */
     if (!dst) {
         need_init = true;
         need_head_update = true;
     } else {
         /* Moreover, even if dst is not NULL, the realloc may move it to a
          * different address in which case we may get a stale tail pointer
          * in dst->head. */
         need_head_update = QTAILQ_EMPTY(&dst->head);
     }
 
     num_opts = count_opts_list(dst);
     num_dst_opts = num_opts;
     num_opts += count_opts_list(list);
     dst = g_realloc(dst, sizeof(QemuOptsList) +
                     (num_opts + 1) * sizeof(QemuOptDesc));
     if (need_init) {
         dst->name = NULL;
         dst->implied_opt_name = NULL;
         dst->merge_lists = false;
     }
     if (need_head_update) {
         QTAILQ_INIT(&dst->head);
     }
     dst->desc[num_dst_opts].name = NULL;
 
     /* append list->desc to dst->desc */
     if (list) {
         desc = list->desc;
         while (desc && desc->name) {
             if (find_desc_by_name(dst->desc, desc->name) == NULL) {
                 dst->desc[num_dst_opts++] = *desc;
                 dst->desc[num_dst_opts].name = NULL;
             }
             desc++;
         }
     }
 
     return dst;
 }