kc3-lang/libxkbcommon/src/registry.c

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• Hash : a50890b1
  Author :
  Date : 2021-03-19T09:46:15
  

  registry: simplify strdup() error handling strdup() is the least likely call to fail here, let's move it to the bottom so we don't need to worry about the allocated string. Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

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• src/registry.c

• /*
   * Copyright © 2020 Red Hat, Inc.
   *
   * 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 (including the next
   * paragraph) 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 "config.h"
  
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <stdbool.h>
  #include <stdlib.h>
  #include <string.h>
  #include <stdint.h>
  #include <libxml/parser.h>
  
  #include "xkbcommon/xkbregistry.h"
  #include "utils.h"
  #include "util-list.h"
  
  struct rxkb_object;
  
  typedef void (*destroy_func_t)(struct rxkb_object *object);
  
  /**
   * All our objects are refcounted and are linked to iterate through them.
   * Abstract those bits away into a shared parent class so we can generate
   * most of the functions through macros.
   */
  struct rxkb_object {
      struct rxkb_object *parent;
      uint32_t refcount;
      struct list link;
      destroy_func_t destroy;
  };
  
  struct rxkb_iso639_code {
      struct rxkb_object base;
      char *code;
  };
  
  struct rxkb_iso3166_code {
      struct rxkb_object base;
      char *code;
  };
  
  enum context_state {
      CONTEXT_NEW,
      CONTEXT_PARSED,
      CONTEXT_FAILED,
  };
  
  struct rxkb_context {
      struct rxkb_object base;
      enum context_state context_state;
  
      bool load_extra_rules_files;
      bool use_secure_getenv;
  
      struct list models;         /* list of struct rxkb_models */
      struct list layouts;        /* list of struct rxkb_layouts */
      struct list option_groups;  /* list of struct rxkb_option_group */
  
      darray(char *) includes;
  
  
      ATTR_PRINTF(3, 0) void (*log_fn)(struct rxkb_context *ctx,
                                       enum rxkb_log_level level,
                                       const char *fmt, va_list args);
      enum rxkb_log_level log_level;
  
      void *userdata;
  };
  
  struct rxkb_model {
      struct rxkb_object base;
  
      char *name;
      char *vendor;
      char *description;
      enum rxkb_popularity popularity;
  };
  
  struct rxkb_layout {
      struct rxkb_object base;
  
      char *name;
      char *brief;
      char *description;
      char *variant;
      enum rxkb_popularity popularity;
  
      struct list iso639s;  /* list of struct rxkb_iso639_code */
      struct list iso3166s; /* list of struct rxkb_iso3166_code */
  };
  
  struct rxkb_option_group {
      struct rxkb_object base;
  
      bool allow_multiple;
      struct list options; /* list of struct rxkb_options */
      char *name;
      char *description;
      enum rxkb_popularity popularity;
  };
  
  struct rxkb_option {
      struct rxkb_object base;
  
      char *name;
      char *brief;
      char *description;
      enum rxkb_popularity popularity;
  };
  
  static bool
  parse(struct rxkb_context *ctx, const char *path,
        enum rxkb_popularity popularity);
  
  ATTR_PRINTF(3, 4)
  static void
  rxkb_log(struct rxkb_context *ctx, enum rxkb_log_level level,
           const char *fmt, ...)
  {
      va_list args;
  
      if (ctx->log_level < level)
          return;
  
      va_start(args, fmt);
      ctx->log_fn(ctx, level, fmt, args);
      va_end(args);
  }
  
  /*
   * The format is not part of the argument list in order to avoid the
   * "ISO C99 requires rest arguments to be used" warning when only the
   * format is supplied without arguments. Not supplying it would still
   * result in an error, though.
   */
  #define log_dbg(ctx, ...) \
      rxkb_log((ctx), RXKB_LOG_LEVEL_DEBUG, __VA_ARGS__)
  #define log_info(ctx, ...) \
      rxkb_log((ctx), RXKB_LOG_LEVEL_INFO, __VA_ARGS__)
  #define log_warn(ctx, ...) \
      rxkb_log((ctx), RXKB_LOG_LEVEL_WARNING,  __VA_ARGS__)
  #define log_err(ctx, ...) \
      rxkb_log((ctx), RXKB_LOG_LEVEL_ERROR,  __VA_ARGS__)
  #define log_wsgo(ctx, ...) \
      rxkb_log((ctx), RXKB_LOG_LEVEL_CRITICAL, __VA_ARGS__)
  
  
  #define DECLARE_REF_UNREF_FOR_TYPE(type_) \
  XKB_EXPORT struct type_ * type_##_ref(struct type_ *object) { \
      rxkb_object_ref(&object->base); \
      return object; \
  } \
  XKB_EXPORT struct type_ * type_##_unref(struct type_ *object) { \
      if (!object) return NULL; \
      return rxkb_object_unref(&object->base); \
  }
  
  #define DECLARE_CREATE_FOR_TYPE(type_) \
  static inline struct type_ * type_##_create(struct rxkb_object *parent) { \
      struct type_ *t = calloc(1, sizeof *t); \
      if (t) \
          rxkb_object_init(&t->base, parent, (destroy_func_t)type_##_destroy); \
      return t; \
  }
  
  #define DECLARE_TYPED_GETTER_FOR_TYPE(type_, field_, rtype_) \
  XKB_EXPORT rtype_ type_##_get_##field_(struct type_ *object) { \
      return object->field_; \
  }
  
  #define DECLARE_GETTER_FOR_TYPE(type_, field_) \
     DECLARE_TYPED_GETTER_FOR_TYPE(type_, field_, const char*)
  
  #define DECLARE_FIRST_NEXT_FOR_TYPE(type_, parent_type_, parent_field_) \
  XKB_EXPORT struct type_ * type_##_first(struct parent_type_ *parent) { \
      struct type_ *o = NULL; \
      if (!list_empty(&parent->parent_field_)) \
          o = list_first_entry(&parent->parent_field_, o, base.link); \
      return o; \
  } \
  XKB_EXPORT struct type_ * \
  type_##_next(struct type_ *o) \
  { \
      struct parent_type_ *parent; \
      struct type_ *next; \
      parent = container_of(o->base.parent, struct parent_type_, base); \
      next = list_first_entry(&o->base.link, o, base.link); \
      if (list_is_last(&parent->parent_field_, &o->base.link)) \
          return NULL; \
      return next; \
  }
  
  static void
  rxkb_object_init(struct rxkb_object *object, struct rxkb_object *parent, destroy_func_t destroy)
  {
      object->refcount = 1;
      object->destroy = destroy;
      object->parent = parent;
      list_init(&object->link);
  }
  
  static void
  rxkb_object_destroy(struct rxkb_object *object)
  {
      if (object->destroy)
          object->destroy(object);
      list_remove(&object->link);
      free(object);
  }
  
  static void *
  rxkb_object_ref(struct rxkb_object *object)
  {
      assert(object->refcount >= 1);
      ++object->refcount;
      return object;
  }
  
  static void *
  rxkb_object_unref(struct rxkb_object *object)
  {
      assert(object->refcount >= 1);
      if (--object->refcount == 0)
          rxkb_object_destroy(object);
      return NULL;
  }
  
  static void
  rxkb_iso639_code_destroy(struct rxkb_iso639_code *code)
  {
      free(code->code);
  }
  
  XKB_EXPORT struct rxkb_iso639_code *
  rxkb_layout_get_iso639_first(struct rxkb_layout *layout)
  {
      struct rxkb_iso639_code *code = NULL;
  
      if (!list_empty(&layout->iso639s))
          code = list_first_entry(&layout->iso639s, code, base.link);
  
      return code;
  }
  
  XKB_EXPORT struct rxkb_iso639_code *
  rxkb_iso639_code_next(struct rxkb_iso639_code *code)
  {
      struct rxkb_iso639_code *next = NULL;
      struct rxkb_layout *layout;
  
      layout = container_of(code->base.parent, struct rxkb_layout, base);
  
      if (list_is_last(&layout->iso639s, &code->base.link))
          return NULL;
  
      next = list_first_entry(&code->base.link, code, base.link);
  
      return next;
  }
  
  DECLARE_REF_UNREF_FOR_TYPE(rxkb_iso639_code);
  DECLARE_CREATE_FOR_TYPE(rxkb_iso639_code);
  DECLARE_GETTER_FOR_TYPE(rxkb_iso639_code, code);
  
  static void
  rxkb_iso3166_code_destroy(struct rxkb_iso3166_code *code)
  {
      free(code->code);
  }
  
  XKB_EXPORT struct rxkb_iso3166_code *
  rxkb_layout_get_iso3166_first(struct rxkb_layout *layout)
  {
      struct rxkb_iso3166_code *code = NULL;
  
      if (!list_empty(&layout->iso3166s))
          code = list_first_entry(&layout->iso3166s, code, base.link);
  
      return code;
  }
  
  XKB_EXPORT struct rxkb_iso3166_code *
  rxkb_iso3166_code_next(struct rxkb_iso3166_code *code)
  {
      struct rxkb_iso3166_code *next = NULL;
      struct rxkb_layout *layout;
  
      layout = container_of(code->base.parent, struct rxkb_layout, base);
  
      if (list_is_last(&layout->iso3166s, &code->base.link))
          return NULL;
  
      next = list_first_entry(&code->base.link, code, base.link);
  
      return next;
  }
  
  DECLARE_REF_UNREF_FOR_TYPE(rxkb_iso3166_code);
  DECLARE_CREATE_FOR_TYPE(rxkb_iso3166_code);
  DECLARE_GETTER_FOR_TYPE(rxkb_iso3166_code, code);
  
  static void
  rxkb_option_destroy(struct rxkb_option *o)
  {
      free(o->name);
      free(o->brief);
      free(o->description);
  }
  
  DECLARE_REF_UNREF_FOR_TYPE(rxkb_option);
  DECLARE_CREATE_FOR_TYPE(rxkb_option);
  DECLARE_GETTER_FOR_TYPE(rxkb_option, name);
  DECLARE_GETTER_FOR_TYPE(rxkb_option, brief);
  DECLARE_GETTER_FOR_TYPE(rxkb_option, description);
  DECLARE_TYPED_GETTER_FOR_TYPE(rxkb_option, popularity, enum rxkb_popularity);
  DECLARE_FIRST_NEXT_FOR_TYPE(rxkb_option, rxkb_option_group, options);
  
  static void
  rxkb_layout_destroy(struct rxkb_layout *l)
  {
      struct rxkb_iso639_code *iso639, *tmp_639;
      struct rxkb_iso3166_code *iso3166, *tmp_3166;
  
      free(l->name);
      free(l->brief);
      free(l->description);
      free(l->variant);
  
      list_for_each_safe(iso639, tmp_639, &l->iso639s, base.link) {
          rxkb_iso639_code_unref(iso639);
      }
      list_for_each_safe(iso3166, tmp_3166, &l->iso3166s, base.link) {
          rxkb_iso3166_code_unref(iso3166);
      }
  }
  
  DECLARE_REF_UNREF_FOR_TYPE(rxkb_layout);
  DECLARE_CREATE_FOR_TYPE(rxkb_layout);
  DECLARE_GETTER_FOR_TYPE(rxkb_layout, name);
  DECLARE_GETTER_FOR_TYPE(rxkb_layout, brief);
  DECLARE_GETTER_FOR_TYPE(rxkb_layout, description);
  DECLARE_GETTER_FOR_TYPE(rxkb_layout, variant);
  DECLARE_TYPED_GETTER_FOR_TYPE(rxkb_layout, popularity, enum rxkb_popularity);
  DECLARE_FIRST_NEXT_FOR_TYPE(rxkb_layout, rxkb_context, layouts);
  
  static void
  rxkb_model_destroy(struct rxkb_model *m)
  {
      free(m->name);
      free(m->vendor);
      free(m->description);
  }
  
  DECLARE_REF_UNREF_FOR_TYPE(rxkb_model);
  DECLARE_CREATE_FOR_TYPE(rxkb_model);
  DECLARE_GETTER_FOR_TYPE(rxkb_model, name);
  DECLARE_GETTER_FOR_TYPE(rxkb_model, vendor);
  DECLARE_GETTER_FOR_TYPE(rxkb_model, description);
  DECLARE_TYPED_GETTER_FOR_TYPE(rxkb_model, popularity, enum rxkb_popularity);
  DECLARE_FIRST_NEXT_FOR_TYPE(rxkb_model, rxkb_context, models);
  
  static void
  rxkb_option_group_destroy(struct rxkb_option_group *og)
  {
      struct rxkb_option *o, *otmp;
  
      free(og->name);
      free(og->description);
  
      list_for_each_safe(o, otmp, &og->options, base.link) {
          rxkb_option_unref(o);
      }
  }
  
  XKB_EXPORT bool
  rxkb_option_group_allows_multiple(struct rxkb_option_group *g)
  {
      return g->allow_multiple;
  }
  
  DECLARE_REF_UNREF_FOR_TYPE(rxkb_option_group);
  DECLARE_CREATE_FOR_TYPE(rxkb_option_group);
  DECLARE_GETTER_FOR_TYPE(rxkb_option_group, name);
  DECLARE_GETTER_FOR_TYPE(rxkb_option_group, description);
  DECLARE_TYPED_GETTER_FOR_TYPE(rxkb_option_group, popularity, enum rxkb_popularity);
  DECLARE_FIRST_NEXT_FOR_TYPE(rxkb_option_group, rxkb_context, option_groups);
  
  static void
  rxkb_context_destroy(struct rxkb_context *ctx)
  {
      struct rxkb_model *m, *mtmp;
      struct rxkb_layout *l, *ltmp;
      struct rxkb_option_group *og, *ogtmp;
      char **path;
  
      list_for_each_safe(m, mtmp, &ctx->models, base.link)
          rxkb_model_unref(m);
      assert(list_empty(&ctx->models));
  
      list_for_each_safe(l, ltmp, &ctx->layouts, base.link)
          rxkb_layout_unref(l);
      assert(list_empty(&ctx->layouts));
  
      list_for_each_safe(og, ogtmp, &ctx->option_groups, base.link)
          rxkb_option_group_unref(og);
      assert(list_empty(&ctx->option_groups));
  
      darray_foreach(path, ctx->includes)
          free(*path);
      darray_free(ctx->includes);
  
      assert(darray_empty(ctx->includes));
  }
  
  DECLARE_REF_UNREF_FOR_TYPE(rxkb_context);
  DECLARE_CREATE_FOR_TYPE(rxkb_context);
  DECLARE_TYPED_GETTER_FOR_TYPE(rxkb_context, log_level, enum rxkb_log_level);
  
  static char *
  rxkb_context_getenv(struct rxkb_context *ctx, const char *name)
  {
      if (ctx->use_secure_getenv) {
          return secure_getenv(name);
      } else {
          return getenv(name);
      }
  }
  
  
  XKB_EXPORT void
  rxkb_context_set_log_level(struct rxkb_context *ctx,
                             enum rxkb_log_level level)
  {
      ctx->log_level = level;
  }
  
  static const char *
  log_level_to_prefix(enum rxkb_log_level level)
  {
      switch (level) {
      case RXKB_LOG_LEVEL_DEBUG:
          return "xkbregistry: DEBUG: ";
      case RXKB_LOG_LEVEL_INFO:
          return "xkbregistry: INFO: ";
      case RXKB_LOG_LEVEL_WARNING:
          return "xkbregistry: WARNING: ";
      case RXKB_LOG_LEVEL_ERROR:
          return "xkbregistry: ERROR: ";
      case RXKB_LOG_LEVEL_CRITICAL:
          return "xkbregistry: CRITICAL: ";
      default:
          return NULL;
      }
  }
  
  ATTR_PRINTF(3, 0) static void
  default_log_fn(struct rxkb_context *ctx, enum rxkb_log_level level,
                 const char *fmt, va_list args)
  {
      const char *prefix = log_level_to_prefix(level);
  
      if (prefix)
          fprintf(stderr, "%s", prefix);
      vfprintf(stderr, fmt, args);
  }
  
  static enum rxkb_log_level
  log_level(const char *level) {
      char *endptr;
      enum rxkb_log_level lvl;
  
      errno = 0;
      lvl = strtol(level, &endptr, 10);
      if (errno == 0 && (endptr[0] == '\0' || is_space(endptr[0])))
          return lvl;
      if (istreq_prefix("crit", level))
          return RXKB_LOG_LEVEL_CRITICAL;
      if (istreq_prefix("err", level))
          return RXKB_LOG_LEVEL_ERROR;
      if (istreq_prefix("warn", level))
          return RXKB_LOG_LEVEL_WARNING;
      if (istreq_prefix("info", level))
          return RXKB_LOG_LEVEL_INFO;
      if (istreq_prefix("debug", level) || istreq_prefix("dbg", level))
          return RXKB_LOG_LEVEL_DEBUG;
  
      return RXKB_LOG_LEVEL_ERROR;
  }
  
  XKB_EXPORT struct rxkb_context *
  rxkb_context_new(enum rxkb_context_flags flags)
  {
      struct rxkb_context *ctx = rxkb_context_create(NULL);
      const char *env;
  
      if (!ctx)
          return NULL;
  
      ctx->context_state = CONTEXT_NEW;
      ctx->load_extra_rules_files = flags & RXKB_CONTEXT_LOAD_EXOTIC_RULES;
      ctx->use_secure_getenv = !(flags & RXKB_CONTEXT_NO_SECURE_GETENV);
      ctx->log_fn = default_log_fn;
      ctx->log_level = RXKB_LOG_LEVEL_ERROR;
  
      /* Environment overwrites defaults. */
      env = rxkb_context_getenv(ctx, "RXKB_LOG_LEVEL");
      if (env)
          rxkb_context_set_log_level(ctx, log_level(env));
  
      list_init(&ctx->models);
      list_init(&ctx->layouts);
      list_init(&ctx->option_groups);
  
      if (!(flags & RXKB_CONTEXT_NO_DEFAULT_INCLUDES) &&
          !rxkb_context_include_path_append_default(ctx)) {
          rxkb_context_unref(ctx);
          return NULL;
      }
  
      return ctx;
  }
  
  XKB_EXPORT void
  rxkb_context_set_log_fn(struct rxkb_context *ctx,
                          void (*log_fn)(struct rxkb_context *ctx,
                                         enum rxkb_log_level level,
                                         const char *fmt, va_list args))
  {
      ctx->log_fn = (log_fn ? log_fn : default_log_fn);
  }
  
  XKB_EXPORT bool
  rxkb_context_include_path_append(struct rxkb_context *ctx, const char *path)
  {
      struct stat stat_buf;
      int err;
      char *tmp = NULL;
      char rules[PATH_MAX];
  
      if (ctx->context_state != CONTEXT_NEW) {
          log_err(ctx, "include paths can only be appended to a new context\n");
          return false;
      }
  
      err = stat(path, &stat_buf);
      if (err != 0)
          return false;
      if (!S_ISDIR(stat_buf.st_mode))
          return false;
  
      if (!check_eaccess(path, R_OK | X_OK))
          return false;
  
      /* Pre-filter for the 99.9% case - if we can't assemble the default ruleset
       * path, complain here instead of during parsing later. The niche cases
       * where this is the wrong behaviour aren't worth worrying about.
       */
      if (!snprintf_safe(rules, sizeof(rules), "%s/rules/%s.xml",
                         path, DEFAULT_XKB_RULES))
          return false;
  
      tmp = strdup(path);
      if (!tmp)
          return false;
  
      darray_append(ctx->includes, tmp);
  
      return true;
  }
  
  XKB_EXPORT bool
  rxkb_context_include_path_append_default(struct rxkb_context *ctx)
  {
      const char *home, *xdg, *root, *extra;
      char user_path[PATH_MAX];
      bool ret = false;
  
      if (ctx->context_state != CONTEXT_NEW) {
          log_err(ctx, "include paths can only be appended to a new context\n");
          return false;
      }
  
      home = rxkb_context_getenv(ctx, "HOME");
  
      xdg = rxkb_context_getenv(ctx, "XDG_CONFIG_HOME");
      if (xdg != NULL) {
          if (snprintf_safe(user_path, sizeof(user_path), "%s/xkb", xdg))
              ret |= rxkb_context_include_path_append(ctx, user_path);
      } else if (home != NULL) {
          /* XDG_CONFIG_HOME fallback is $HOME/.config/ */
          if (snprintf_safe(user_path, sizeof(user_path), "%s/.config/xkb", home))
              ret |= rxkb_context_include_path_append(ctx, user_path);
      }
  
      if (home != NULL) {
          if (snprintf_safe(user_path, sizeof(user_path), "%s/.xkb", home))
              ret |= rxkb_context_include_path_append(ctx, user_path);
      }
  
      extra = rxkb_context_getenv(ctx, "XKB_CONFIG_EXTRA_PATH");
      if (extra != NULL)
          ret |= rxkb_context_include_path_append(ctx, extra);
      else
          ret |= rxkb_context_include_path_append(ctx, DFLT_XKB_CONFIG_EXTRA_PATH);
  
      root = rxkb_context_getenv(ctx, "XKB_CONFIG_ROOT");
      if (root != NULL)
          ret |= rxkb_context_include_path_append(ctx, root);
      else
          ret |= rxkb_context_include_path_append(ctx, DFLT_XKB_CONFIG_ROOT);
  
      return ret;
  }
  
  XKB_EXPORT bool
  rxkb_context_parse_default_ruleset(struct rxkb_context *ctx)
  {
      return rxkb_context_parse(ctx, DEFAULT_XKB_RULES);
  }
  
  XKB_EXPORT bool
  rxkb_context_parse(struct rxkb_context *ctx, const char *ruleset)
  {
      char **path;
      bool success = false;
  
      if (ctx->context_state != CONTEXT_NEW) {
          log_err(ctx, "parse must only be called on a new context\n");
          return false;
      }
  
      darray_foreach_reverse(path, ctx->includes) {
          char rules[PATH_MAX];
  
          if (snprintf_safe(rules, sizeof(rules), "%s/rules/%s.xml",
                             *path, ruleset)) {
              log_dbg(ctx, "Parsing %s\n", rules);
              if (parse(ctx, rules, RXKB_POPULARITY_STANDARD))
                  success = true;
          }
  
          if (ctx->load_extra_rules_files &&
              snprintf_safe(rules, sizeof(rules), "%s/rules/%s.extras.xml",
                            *path, ruleset)) {
              log_dbg(ctx, "Parsing %s\n", rules);
              if (parse(ctx, rules, RXKB_POPULARITY_EXOTIC))
                  success = true;
          }
      }
  
      ctx->context_state = success ? CONTEXT_PARSED : CONTEXT_FAILED;
  
      return success;
  }
  
  
  XKB_EXPORT void
  rxkb_context_set_user_data(struct rxkb_context *ctx, void *userdata)
  {
      ctx->userdata = userdata;
  }
  
  XKB_EXPORT void *
  rxkb_context_get_user_data(struct rxkb_context *ctx)
  {
      return ctx->userdata;
  }
  
  static inline bool
  is_node(xmlNode *node, const char *name)
  {
      return node->type == XML_ELEMENT_NODE &&
          xmlStrEqual(node->name, (const xmlChar*)name);
  }
  
  /* return a copy of the text content from the first text node of this node */
  static char *
  extract_text(xmlNode *node)
  {
      xmlNode *n;
  
      for (n = node->children; n; n = n->next) {
          if (n->type == XML_TEXT_NODE)
              return (char *)xmlStrdup(n->content);
      }
      return NULL;
  }
  
  static bool
  parse_config_item(struct rxkb_context *ctx,
                    xmlNode *parent,
                    char **name,
                    char **description,
                    char **brief,
                    char **vendor)
  {
      xmlNode *node = NULL;
      xmlNode *ci = NULL;
  
      for (ci = parent->children; ci; ci = ci->next) {
          if (is_node(ci, "configItem")) {
              *name = NULL;
              *description = NULL;
              *brief = NULL;
              *vendor = NULL;
  
              for (node = ci->children; node; node = node->next) {
                  if (is_node(node, "name"))
                      *name = extract_text(node);
                  else if (is_node(node, "description"))
                      *description = extract_text(node);
                  else if (is_node(node, "shortDescription"))
                      *brief = extract_text(node);
                  else if (is_node(node, "vendor"))
                      *vendor = extract_text(node);
                  /* Note: the DTD allows for vendor + brief but models only use
                   * vendor and everything else only uses shortDescription */
              }
  
              if (!*name || !strlen(*name))  {
                  log_err(ctx, "xml:%d: missing required element 'name'\n",
                          ci->line);
                  free(*name);
                  free(*description);
                  free(*brief);
                  free(*vendor);
                  return false;
              }
  
              return true; /* only one configItem allowed in the dtd */
          }
      }
  
      return false;
  }
  
  static void
  parse_model(struct rxkb_context *ctx, xmlNode *model,
              enum rxkb_popularity popularity)
  {
      char *name, *description, *brief, *vendor;
  
      if (parse_config_item(ctx, model, &name, &description, &brief, &vendor)) {
          struct rxkb_model *m;
  
          list_for_each(m, &ctx->models, base.link) {
              if (streq(m->name, name)) {
                  free(name);
                  free(description);
                  free(brief);
                  free(vendor);
                  return;
              }
          }
  
          /* new model */
          m = rxkb_model_create(&ctx->base);
          m->name = name;
          m->description = description;
          m->vendor = vendor;
          m->popularity = popularity;
          list_append(&ctx->models, &m->base.link);
      }
  }
  
  static void
  parse_model_list(struct rxkb_context *ctx, xmlNode *model_list,
                  enum rxkb_popularity popularity)
  {
      xmlNode *node = NULL;
  
      for (node = model_list->children; node; node = node->next) {
          if (is_node(node, "model"))
              parse_model(ctx, node, popularity);
      }
  }
  
  static void
  parse_language_list(xmlNode *language_list, struct rxkb_layout *layout)
  {
      xmlNode *node = NULL;
      struct rxkb_iso639_code *code;
  
      for (node = language_list->children; node; node = node->next) {
          if (is_node(node, "iso639Id")) {
              char *str = extract_text(node);
              struct rxkb_object *parent;
  
              if (!str || strlen(str) != 3) {
                  free(str);
                  continue;
              }
  
              parent = &layout->base;
              code = rxkb_iso639_code_create(parent);
              code->code = str;
              list_append(&layout->iso639s, &code->base.link);
          }
      }
  }
  
  static void
  parse_country_list(xmlNode *country_list, struct rxkb_layout *layout)
  {
      xmlNode *node = NULL;
      struct rxkb_iso3166_code *code;
  
      for (node = country_list->children; node; node = node->next) {
          if (is_node(node, "iso3166Id")) {
              char *str = extract_text(node);
              struct rxkb_object *parent;
  
              if (!str || strlen(str) != 2) {
                  free(str);
                  continue;
              }
  
              parent = &layout->base;
              code = rxkb_iso3166_code_create(parent);
              code->code = str;
              list_append(&layout->iso3166s, &code->base.link);
          }
      }
  }
  
  static void
  parse_variant(struct rxkb_context *ctx, struct rxkb_layout *l,
                xmlNode *variant, enum rxkb_popularity popularity)
  {
      xmlNode *ci;
      char *name, *description, *brief, *vendor;
  
      if (parse_config_item(ctx, variant, &name, &description, &brief, &vendor)) {
          struct rxkb_layout *v;
          bool exists = false;
  
          list_for_each(v, &ctx->layouts, base.link) {
              if (streq(v->name, name) && streq(v->name, l->name)) {
                  exists = true;
                  break;
              }
          }
  
          if (!exists) {
              v = rxkb_layout_create(&ctx->base);
              list_init(&v->iso639s);
              list_init(&v->iso3166s);
              v->name = strdup(l->name);
              v->variant = name;
              v->description = description;
              // if variant omits brief, inherit from parent layout.
              v->brief = brief == NULL ? strdup_safe(l->brief) : brief;
              v->popularity = popularity;
              list_append(&ctx->layouts, &v->base.link);
  
              for (ci = variant->children; ci; ci = ci->next) {
                  xmlNode *node;
  
                  if (!is_node(ci, "configItem"))
                      continue;
  
                  bool found_language_list = false;
                  bool found_country_list = false;
                  for (node = ci->children; node; node = node->next) {
                      if (is_node(node, "languageList")) {
                          parse_language_list(node, v);
                          found_language_list = true;
                      }
                      if (is_node(node, "countryList")) {
                          parse_country_list(node, v);
                          found_country_list = true;
                      }
                  }
                  if (!found_language_list) {
                      // inherit from parent layout
                      struct rxkb_iso639_code* x;
                      list_for_each(x, &l->iso639s, base.link) {
                          struct rxkb_iso639_code* code = rxkb_iso639_code_create(&v->base);
                          code->code = strdup(x->code);
                          list_append(&v->iso639s, &code->base.link);
                      }
                  }
                  if (!found_country_list) {
                      // inherit from parent layout
                      struct rxkb_iso3166_code* x;
                      list_for_each(x, &l->iso3166s, base.link) {
                          struct rxkb_iso3166_code* code = rxkb_iso3166_code_create(&v->base);
                          code->code = strdup(x->code);
                          list_append(&v->iso3166s, &code->base.link);
                      }
                  }
              }
          } else {
              free(name);
              free(description);
              free(brief);
              free(vendor);
          }
      }
  }
  
  static void
  parse_variant_list(struct rxkb_context *ctx, struct rxkb_layout *l,
                     xmlNode *variant_list, enum rxkb_popularity popularity)
  {
      xmlNode *node = NULL;
  
      for (node = variant_list->children; node; node = node->next) {
          if (is_node(node, "variant"))
              parse_variant(ctx, l, node, popularity);
      }
  }
  
  static void
  parse_layout(struct rxkb_context *ctx, xmlNode *layout,
               enum rxkb_popularity popularity)
  {
      char *name, *description, *brief, *vendor;
      struct rxkb_layout *l;
      xmlNode *node = NULL;
      bool exists = false;
  
      if (!parse_config_item(ctx, layout, &name, &description, &brief, &vendor))
          return;
  
      list_for_each(l, &ctx->layouts, base.link) {
          if (streq(l->name, name) && l->variant == NULL) {
              exists = true;
              break;
          }
      }
  
      if (!exists) {
          l = rxkb_layout_create(&ctx->base);
          list_init(&l->iso639s);
          list_init(&l->iso3166s);
          l->name = name;
          l->variant = NULL;
          l->description = description;
          l->brief = brief;
          l->popularity = popularity;
          list_append(&ctx->layouts, &l->base.link);
      } else {
          free(name);
          free(description);
          free(brief);
          free(vendor);
      }
  
      for (node = layout->children; node; node = node->next) {
          if (is_node(node, "variantList")) {
              parse_variant_list(ctx, l, node, popularity);
          }
          if (!exists && is_node(node, "configItem")) {
              xmlNode *ll;
              for (ll = node->children; ll; ll = ll->next) {
                  if (is_node(ll, "languageList"))
                      parse_language_list(ll, l);
                  if (is_node(ll, "countryList"))
                      parse_country_list(ll, l);
              }
          }
      }
  }
  
  static void
  parse_layout_list(struct rxkb_context *ctx, xmlNode *layout_list,
                    enum rxkb_popularity popularity)
  {
      xmlNode *node = NULL;
  
      for (node = layout_list->children; node; node = node->next) {
          if (is_node(node, "layout"))
              parse_layout(ctx, node, popularity);
      }
  }
  
  static void
  parse_option(struct rxkb_context *ctx, struct rxkb_option_group *group,
               xmlNode *option, enum rxkb_popularity popularity)
  {
      char *name, *description, *brief, *vendor;
  
      if (parse_config_item(ctx, option, &name, &description, &brief, &vendor)) {
          struct rxkb_option *o;
  
          list_for_each(o, &group->options, base.link) {
              if (streq(o->name, name)) {
                  free(name);
                  free(description);
                  free(brief);
                  free(vendor);
                  return;
              }
          }
  
          o = rxkb_option_create(&group->base);
          o->name = name;
          o->description = description;
          o->popularity = popularity;
          list_append(&group->options, &o->base.link);
      }
  }
  
  static void
  parse_group(struct rxkb_context *ctx, xmlNode *group,
              enum rxkb_popularity popularity)
  {
      char *name, *description, *brief, *vendor;
      struct rxkb_option_group *g;
      xmlNode *node = NULL;
      xmlChar *multiple;
      bool exists = false;
  
      if (!parse_config_item(ctx, group, &name, &description, &brief, &vendor))
          return;
  
      list_for_each(g, &ctx->option_groups, base.link) {
          if (streq(g->name, name)) {
              exists = true;
              break;
          }
      }
  
      if (!exists) {
          g = rxkb_option_group_create(&ctx->base);
          g->name = name;
          g->description = description;
          g->popularity = popularity;
  
          multiple = xmlGetProp(group, (const xmlChar*)"allowMultipleSelection");
          if (multiple && xmlStrEqual(multiple, (const xmlChar*)"true"))
              g->allow_multiple = true;
          xmlFree(multiple);
  
          list_init(&g->options);
          list_append(&ctx->option_groups, &g->base.link);
      } else {
          free(name);
          free(description);
          free(brief);
          free(vendor);
      }
  
      for (node = group->children; node; node = node->next) {
          if (is_node(node, "option"))
              parse_option(ctx, g, node, popularity);
      }
  }
  
  static void
  parse_option_list(struct rxkb_context *ctx, xmlNode *option_list,
                    enum rxkb_popularity popularity)
  {
      xmlNode *node = NULL;
  
      for (node = option_list->children; node; node = node->next) {
          if (is_node(node, "group"))
              parse_group(ctx, node, popularity);
      }
  }
  
  static void
  parse_rules_xml(struct rxkb_context *ctx, xmlNode *root,
                  enum rxkb_popularity popularity)
  {
      xmlNode *node = NULL;
  
      for (node = root->children; node; node = node->next) {
          if (is_node(node, "modelList"))
              parse_model_list(ctx, node, popularity);
          else if (is_node(node, "layoutList"))
              parse_layout_list(ctx, node, popularity);
          else if (is_node(node, "optionList"))
              parse_option_list(ctx, node, popularity);
      }
  }
  
  static void
  ATTR_PRINTF(2, 0)
  xml_error_func(void *ctx, const char *msg, ...)
  {
      static char buf[PATH_MAX];
      static int slen = 0;
      va_list args;
      int rc;
  
      /* libxml2 prints IO errors from bad includes paths by
       * calling the error function once per word. So we get to
       * re-assemble the message here and print it when we get
       * the line break. My enthusiasm about this is indescribable.
       */
      va_start(args, msg);
      rc = vsnprintf(&buf[slen], sizeof(buf) - slen, msg, args);
      va_end(args);
  
      /* This shouldn't really happen */
      if (rc < 0) {
          log_err(ctx, "+++ out of cheese error. redo from start +++\n");
          slen = 0;
          memset(buf, 0, sizeof(buf));
          return;
      }
  
      slen += rc;
      if (slen >= (int)sizeof(buf)) {
          /* truncated, let's flush this */
          buf[sizeof(buf) - 1] = '\n';
          slen = sizeof(buf);
      }
  
      /* We're assuming here that the last character is \n. */
      if (buf[slen - 1] == '\n') {
          log_err(ctx, "%s", buf);
          memset(buf, 0, sizeof(buf));
          slen = 0;
      }
  }
  
  static bool
  validate(struct rxkb_context *ctx, xmlDoc *doc)
  {
      bool success = false;
      xmlValidCtxt *dtdvalid = NULL;
      xmlDtd *dtd = NULL;
      xmlParserInputBufferPtr buf = NULL;
      /* This is a modified version of the xkeyboard-config xkb.dtd. That one
       * requires modelList, layoutList and optionList, we
       * allow for any of those to be missing.
       */
      const char dtdstr[] =
          "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
          "<!ELEMENT xkbConfigRegistry (modelList?, layoutList?, optionList?)>\n"
          "<!ATTLIST xkbConfigRegistry version CDATA \"1.1\">\n"
          "<!ELEMENT modelList (model*)>\n"
          "<!ELEMENT model (configItem)>\n"
          "<!ELEMENT layoutList (layout*)>\n"
          "<!ELEMENT layout (configItem,  variantList?)>\n"
          "<!ELEMENT optionList (group*)>\n"
          "<!ELEMENT variantList (variant*)>\n"
          "<!ELEMENT variant (configItem)>\n"
          "<!ELEMENT group (configItem, option*)>\n"
          "<!ATTLIST group allowMultipleSelection (true|false) \"false\">\n"
          "<!ELEMENT option (configItem)>\n"
          "<!ELEMENT configItem (name, shortDescription?, description?, vendor?, countryList?, languageList?, hwList?)>\n"
          "<!ATTLIST configItem popularity (standard|exotic) \"standard\">\n"
          "<!ELEMENT name (#PCDATA)>\n"
          "<!ELEMENT shortDescription (#PCDATA)>\n"
          "<!ELEMENT description (#PCDATA)>\n"
          "<!ELEMENT vendor (#PCDATA)>\n"
          "<!ELEMENT countryList (iso3166Id+)>\n"
          "<!ELEMENT iso3166Id (#PCDATA)>\n"
          "<!ELEMENT languageList (iso639Id+)>\n"
          "<!ELEMENT iso639Id (#PCDATA)>\n"
          "<!ELEMENT hwList (hwId+)>\n"
          "<!ELEMENT hwId (#PCDATA)>\n";
  
      /* Note: do not use xmlParserInputBufferCreateStatic, it generates random
       * DTD validity errors for unknown reasons */
      buf = xmlParserInputBufferCreateMem(dtdstr, sizeof(dtdstr),
                                          XML_CHAR_ENCODING_UTF8);
      if (!buf)
          return false;
  
      dtd = xmlIOParseDTD(NULL, buf, XML_CHAR_ENCODING_UTF8);
      if (!dtd) {
          log_err(ctx, "Failed to load DTD\n");
          return false;
      }
  
      dtdvalid = xmlNewValidCtxt();
      if (xmlValidateDtd(dtdvalid, doc, dtd))
          success = true;
  
      if (dtd)
          xmlFreeDtd(dtd);
      if (dtdvalid)
          xmlFreeValidCtxt(dtdvalid);
  
      return success;
  }
  
  static bool
  parse(struct rxkb_context *ctx, const char *path,
        enum rxkb_popularity popularity)
  {
      bool success = false;
      xmlDoc *doc = NULL;
      xmlNode *root = NULL;
  
      if (!check_eaccess(path, R_OK))
          return false;
  
      LIBXML_TEST_VERSION
  
      xmlSetGenericErrorFunc(ctx, xml_error_func);
  
      doc = xmlParseFile(path);
      if (!doc)
          return false;
  
      if (!validate(ctx, doc)) {
          log_err(ctx, "XML error: failed to validate document at %s\n", path);
          goto error;
      }
  
      root = xmlDocGetRootElement(doc);
      parse_rules_xml(ctx, root, popularity);
  
      success = true;
  error:
      xmlFreeDoc(doc);
  
      return success;
  }
  

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