res_sorcery_config.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2012 - 2013, Digium, Inc.
 *
 * Joshua Colp <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*!
 * \file
 *
 * \brief Sorcery Configuration File Object Wizard
 *
 * \author Joshua Colp <[email protected]>
 */

/*** MODULEINFO
 <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include <regex.h>

#include "asterisk/module.h"
#include "asterisk/sorcery.h"
#include "asterisk/astobj2.h"
#include "asterisk/config.h"
#include "asterisk/uuid.h"
#include "asterisk/hashtab.h"

/*! \brief Structure for storing configuration file sourced objects */
struct sorcery_config {
 /*! \brief UUID for identifying us when opening a configuration file */
 char uuid[AST_UUID_STR_LEN];

 /*! \brief Objects retrieved from the configuration file */
 struct ao2_global_obj objects;

 /*! \brief Any specific variable criteria for considering a defined category for this object */
 struct ast_variable *criteria;

 /*! \brief An explicit name for the configuration section, with it there can be only one */
 char *explicit_name;

 /*! \brief Number of buckets to use for objects */
 unsigned int buckets;

 /*! \brief Enable file level integrity instead of object level */
 unsigned int file_integrity:1;

 /*! \brief Enable enforcement of a single configuration object of this type */
 unsigned int single_object:1;

 /*! \brief Configuration is invalid in some way, force reload */
 unsigned int configuration_invalid:1;

 /*! \brief Configuration contains at least one object with dynamic contents */
 unsigned int has_dynamic_contents:1;

 /*! \brief Filename of the configuration file */
 char filename[];
};

/*! \brief Structure used for fields comparison */
struct sorcery_config_fields_cmp_params {
 /*! \brief Pointer to the sorcery structure */
 const struct ast_sorcery *sorcery;

 /*! \brief Pointer to the fields to check */
 const struct ast_variable *fields;

 /*! \brief Regular expression for checking object id */
 regex_t *regex;

 /*! \brief Prefix for matching object id */
 const char *prefix;

 /*! \brief Prefix length in bytes for matching object id */
 const size_t prefix_len;

 /*! \brief Optional container to put object into */
 struct ao2_container *container;
};

static void *sorcery_config_open(const char *data);
static void sorcery_config_load(void *data, const struct ast_sorcery *sorcery, const char *type);
static void sorcery_config_reload(void *data, const struct ast_sorcery *sorcery, const char *type);
static void *sorcery_config_retrieve_id(const struct ast_sorcery *sorcery, void *data, const char *type, const char *id);
static void *sorcery_config_retrieve_fields(const struct ast_sorcery *sorcery, void *data, const char *type, const struct ast_variable *fields);
static void sorcery_config_retrieve_multiple(const struct ast_sorcery *sorcery, void *data, const char *type, struct ao2_container *objects,
 const struct ast_variable *fields);
static void sorcery_config_retrieve_regex(const struct ast_sorcery *sorcery, void *data, const char *type, struct ao2_container *objects, const char *regex);
static void sorcery_config_retrieve_prefix(const struct ast_sorcery *sorcery, void *data, const char *type, struct ao2_container *objects, const char *prefix, const size_t prefix_len);
static void sorcery_config_close(void *data);

static struct ast_sorcery_wizard config_object_wizard = {
 .name = "config",
 .open = sorcery_config_open,
 .load = sorcery_config_load,
 .reload = sorcery_config_reload,
 .force_reload = sorcery_config_load,
 .retrieve_id = sorcery_config_retrieve_id,
 .retrieve_fields = sorcery_config_retrieve_fields,
 .retrieve_multiple = sorcery_config_retrieve_multiple,
 .retrieve_regex = sorcery_config_retrieve_regex,
 .retrieve_prefix = sorcery_config_retrieve_prefix,
 .close = sorcery_config_close,
};

/*! \brief Destructor function for sorcery config */
static void sorcery_config_destructor(void *obj)
{
 struct sorcery_config *config = obj;

 ao2_global_obj_release(config->objects);
 ast_rwlock_destroy(&config->objects.lock);
 ast_variables_destroy(config->criteria);
 ast_free(config->explicit_name);
}

static int sorcery_config_fields_cmp(void *obj, void *arg, int flags)
{
 const struct sorcery_config_fields_cmp_params *params = arg;
 RAII_VAR(struct ast_variable *, objset, NULL, ast_variables_destroy);

 if (params->regex) {
 /* If a regular expression has been provided see if it matches, otherwise move on */
 if (!regexec(params->regex, ast_sorcery_object_get_id(obj), 0, NULL, 0)) {
 ao2_link(params->container, obj);
 }
 return 0;
 } else if (params->prefix) {
 if (!strncmp(params->prefix, ast_sorcery_object_get_id(obj), params->prefix_len)) {
 ao2_link(params->container, obj);
 }
 return 0;
 } else if (params->fields &&
 (!(objset = ast_sorcery_objectset_create(params->sorcery, obj)) ||
 (!ast_variable_lists_match(objset, params->fields, 0)))) {
 /* If we can't turn the object into an object set OR if differences exist between the fields
 * passed in and what are present on the object they are not a match.
 */
 return 0;
 }

 /* We want this object */
 if (params->container) {
 /*
 * We are putting the found objects into the given container instead
 * of the normal container traversal return mechanism.
 */
 ao2_link(params->container, obj);
 return 0;
 } else {
 return CMP_MATCH;
 }
}

static void *sorcery_config_retrieve_fields(const struct ast_sorcery *sorcery, void *data, const char *type, const struct ast_variable *fields)
{
 struct sorcery_config *config = data;
 RAII_VAR(struct ao2_container *, objects, ao2_global_obj_ref(config->objects), ao2_cleanup);
 struct sorcery_config_fields_cmp_params params = {
 .sorcery = sorcery,
 .fields = fields,
 .container = NULL,
 };

 /* If no fields are present return nothing, we require *something*, same goes if no objects exist yet */
 if (!objects || !fields) {
 return NULL;
 }

 return ao2_callback(objects, 0, sorcery_config_fields_cmp, &params);
}

static void *sorcery_config_retrieve_id(const struct ast_sorcery *sorcery, void *data, const char *type, const char *id)
{
 struct sorcery_config *config = data;
 RAII_VAR(struct ao2_container *, objects, ao2_global_obj_ref(config->objects), ao2_cleanup);

 return objects ? ao2_find(objects, id, OBJ_SEARCH_KEY) : NULL;
}

static void sorcery_config_retrieve_multiple(const struct ast_sorcery *sorcery, void *data, const char *type, struct ao2_container *objects, const struct ast_variable *fields)
{
 struct sorcery_config *config = data;
 RAII_VAR(struct ao2_container *, config_objects, ao2_global_obj_ref(config->objects), ao2_cleanup);
 struct sorcery_config_fields_cmp_params params = {
 .sorcery = sorcery,
 .fields = fields,
 .container = objects,
 };

 if (!config_objects) {
 return;
 }

 ao2_callback(config_objects, OBJ_NODATA | OBJ_MULTIPLE, sorcery_config_fields_cmp, &params);
}

static void sorcery_config_retrieve_regex(const struct ast_sorcery *sorcery, void *data, const char *type, struct ao2_container *objects, const char *regex)
{
 struct sorcery_config *config = data;
 RAII_VAR(struct ao2_container *, config_objects, ao2_global_obj_ref(config->objects), ao2_cleanup);
 regex_t expression;
 struct sorcery_config_fields_cmp_params params = {
 .sorcery = sorcery,
 .container = objects,
 .regex = &expression,
 };

 if (ast_strlen_zero(regex)) {
 regex = ".";
 }

 if (!config_objects || regcomp(&expression, regex, REG_EXTENDED | REG_NOSUB)) {
 return;
 }

 ao2_callback(config_objects, OBJ_NODATA | OBJ_MULTIPLE, sorcery_config_fields_cmp, &params);
 regfree(&expression);
}

static void sorcery_config_retrieve_prefix(const struct ast_sorcery *sorcery, void *data, const char *type, struct ao2_container *objects, const char *prefix, const size_t prefix_len)
{
 struct sorcery_config *config = data;
 RAII_VAR(struct ao2_container *, config_objects, ao2_global_obj_ref(config->objects), ao2_cleanup);
 struct sorcery_config_fields_cmp_params params = {
 .sorcery = sorcery,
 .container = objects,
 .prefix = prefix,
 .prefix_len = prefix_len,
 };

 if (!config_objects) {
 return;
 }

 ao2_callback(config_objects, OBJ_NODATA | OBJ_MULTIPLE, sorcery_config_fields_cmp, &params);
}

/*! \brief Internal function which determines if a category matches based on explicit name */
static int sorcery_is_explicit_name_met(const struct ast_sorcery *sorcery, const char *type,
 struct ast_category *category, struct sorcery_config *config)
{
 struct ast_sorcery_object_type *object_type;
 struct ast_variable *field;
 int met = 1;

 if (ast_strlen_zero(config->explicit_name) || strcmp(ast_category_get_name(category), config->explicit_name)) {
 return 0;
 }

 object_type = ast_sorcery_get_object_type(sorcery, type);
 if (!object_type) {
 return 0;
 }

 /* We iterate the configured fields to see if we don't know any, if we don't then
 * this is likely not for the given type and we skip it. If it actually is then criteria
 * may pick it up in which case it would just get rejected as an invalid configuration later.
 */
 for (field = ast_category_first(category); field; field = field->next) {
 if (!ast_sorcery_is_object_field_registered(object_type, field->name)) {
 met = 0;
 break;
 }
 }

 ao2_ref(object_type, -1);

 return met;
}

/*! \brief Internal function which determines if a category matches based on criteria */
static int sorcery_is_criteria_met(struct ast_category *category, struct sorcery_config *config)
{
 RAII_VAR(struct ast_variable *, diff, NULL, ast_variables_destroy);

 if (!config->criteria) {
 return 0;
 }

 return (!ast_sorcery_changeset_create(ast_category_first(category), config->criteria, &diff) && !diff) ? 1 : 0;
}

/*! \brief Internal function which determines if criteria has been met for considering an object set applicable */
static int sorcery_is_configuration_met(const struct ast_sorcery *sorcery, const char *type,
 struct ast_category *category, struct sorcery_config *config)
{
 if (!config->criteria && ast_strlen_zero(config->explicit_name)) {
 /* Nothing is configured to allow specific matching, so accept it! */
 return 1;
 } else if (sorcery_is_explicit_name_met(sorcery, type, category, config)) {
 return 1;
 } else if (sorcery_is_criteria_met(category, config)) {
 return 1;
 } else {
 /* Nothing explicitly matched so reject */
 return 0;
 }
}

static void sorcery_config_internal_load(void *data, const struct ast_sorcery *sorcery, const char *type, unsigned int reload)
{
 struct sorcery_config *config = data;
 struct ast_flags flags = { reload && !config->configuration_invalid && !config->has_dynamic_contents ? CONFIG_FLAG_FILEUNCHANGED : 0 };
 struct ast_config *cfg = ast_config_load2(config->filename, config->uuid, flags);
 struct ast_category *category = NULL;
 RAII_VAR(struct ao2_container *, objects, NULL, ao2_cleanup);
 const char *id = NULL;
 unsigned int buckets = 0;
 unsigned int has_dynamic_contents = 0;

 if (!cfg) {
 ast_log(LOG_ERROR, "Unable to load config file '%s'\n", config->filename);
 return;
 } else if (cfg == CONFIG_STATUS_FILEUNCHANGED) {
 ast_debug(1, "Config file '%s' was unchanged\n", config->filename);
 return;
 } else if (cfg == CONFIG_STATUS_FILEINVALID) {
 ast_log(LOG_ERROR, "Contents of config file '%s' are invalid and cannot be parsed\n", config->filename);
 return;
 }

 /* When parsing the configuration assume it is valid until proven otherwise */
 config->configuration_invalid = 0;

 if (!config->buckets) {
 while ((category = ast_category_browse_filtered(cfg, NULL, category, NULL))) {

 /* If given configuration has not been met skip the category, it is not applicable */
 if (!sorcery_is_configuration_met(sorcery, type, category, config)) {
 continue;
 }

 buckets++;
 }

 /* Determine the optimal number of buckets */
 while (buckets && !ast_is_prime(buckets)) {
 /* This purposely goes backwards to ensure that the container doesn't have a ton of
 * empty buckets for objects that will never get added.
 */
 buckets--;
 }

 if (!buckets) {
 buckets = 1;
 }
 } else {
 buckets = config->buckets;
 }

 /* For single object configurations there can only ever be one bucket, if there's more than the single
 * object requirement has been violated.
 */
 if (config->single_object && buckets > 1) {
 ast_log(LOG_ERROR, "Config file '%s' could not be loaded; configuration contains more than one object of type '%s'\n",
 config->filename, type);
 ast_config_destroy(cfg);
 config->configuration_invalid = 1;
 return;
 }

 ast_debug(2, "Using bucket size of '%d' for objects of type '%s' from '%s'\n",
 buckets, type, config->filename);

 objects = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_NOLOCK, 0, buckets,
 ast_sorcery_object_id_hash, NULL, ast_sorcery_object_id_compare);
 if (!objects) {
 ast_log(LOG_ERROR, "Could not create bucket for new objects from '%s', keeping existing objects\n",
 config->filename);
 ast_config_destroy(cfg);
 config->configuration_invalid = 1; /* Not strictly invalid but we want to try next time */
 return;
 }

 while ((category = ast_category_browse_filtered(cfg, NULL, category, NULL))) {
 RAII_VAR(void *, obj, NULL, ao2_cleanup);
 id = ast_category_get_name(category);

 /* If given configurationhas not been met skip the category, it is not applicable */
 if (!sorcery_is_configuration_met(sorcery, type, category, config)) {
 continue;
 }

 /* Confirm an object with this id does not already exist in the bucket.
 * If it exists, however, the configuration is invalid so stop
 * processing and destroy it. */
 obj = ao2_find(objects, id, OBJ_SEARCH_KEY);
 if (obj) {
 ast_log(LOG_ERROR, "Config file '%s' could not be loaded; configuration contains a duplicate object: '%s' of type '%s'\n",
 config->filename, id, type);
 ast_config_destroy(cfg);
 config->configuration_invalid = 1;
 return;
 }

 if (!(obj = ast_sorcery_alloc(sorcery, type, id)) ||
 ast_sorcery_objectset_apply(sorcery, obj, ast_category_first(category))) {

 if (config->file_integrity) {
 ast_log(LOG_ERROR, "Config file '%s' could not be loaded due to error with object '%s' of type '%s'\n",
 config->filename, id, type);
 ast_config_destroy(cfg);
 config->configuration_invalid = 1;
 return;
 } else {
 ast_log(LOG_ERROR, "Could not create an object of type '%s' with id '%s' from configuration file '%s'\n",
 type, id, config->filename);
 config->configuration_invalid = 1;
 }

 ao2_cleanup(obj);

 /* To ensure we don't lose the object that already exists we retrieve it from the old objects container and add it to the new one */
 if (!(obj = sorcery_config_retrieve_id(sorcery, data, type, id))) {
 continue;
 }

 ast_log(LOG_NOTICE, "Retaining existing configuration for object of type '%s' with id '%s'\n", type, id);
 }

 /* We store the dynamic contents state until the end in case this reload or load
 * gets rolled back.
 */
 has_dynamic_contents |= ast_sorcery_object_has_dynamic_contents(obj);

 ao2_link(objects, obj);
 }

 config->has_dynamic_contents = has_dynamic_contents;
 ao2_global_obj_replace_unref(config->objects, objects);
 ast_config_destroy(cfg);
}

static void sorcery_config_load(void *data, const struct ast_sorcery *sorcery, const char *type)
{
 sorcery_config_internal_load(data, sorcery, type, 0);
}

static void sorcery_config_reload(void *data, const struct ast_sorcery *sorcery, const char *type)
{
 sorcery_config_internal_load(data, sorcery, type, 1);
}

static void *sorcery_config_open(const char *data)
{
 char *tmp;
 char *filename;
 char *option;
 struct sorcery_config *config;

 if (ast_strlen_zero(data)) {
 return NULL;
 }

 tmp = ast_strdupa(data);
 filename = strsep(&tmp, ",");

 if (ast_strlen_zero(filename) || !(config = ao2_alloc_options(sizeof(*config) + strlen(filename) + 1, sorcery_config_destructor, AO2_ALLOC_OPT_LOCK_NOLOCK))) {
 return NULL;
 }

 ast_uuid_generate_str(config->uuid, sizeof(config->uuid));

 ast_rwlock_init(&config->objects.lock);
 strcpy(config->filename, filename);

 while ((option = strsep(&tmp, ","))) {
 char *name = strsep(&option, "="), *value = option;

 if (!strcasecmp(name, "buckets")) {
 if (sscanf(value, "%30u", &config->buckets) != 1) {
 ast_log(LOG_ERROR, "Unsupported bucket size of '%s' used for configuration file '%s', defaulting to automatic determination\n",
 value, filename);
 }
 } else if (!strcasecmp(name, "integrity")) {
 if (!strcasecmp(value, "file")) {
 config->file_integrity = 1;
 } else if (!strcasecmp(value, "object")) {
 config->file_integrity = 0;
 } else {
 ast_log(LOG_ERROR, "Unsupported integrity value of '%s' used for configuration file '%s', defaulting to 'object'\n",
 value, filename);
 }
 } else if (!strcasecmp(name, "criteria")) {
 char *field = strsep(&value, "=");
 struct ast_variable *criteria = ast_variable_new(field, value, "");

 if (criteria) {
 criteria->next = config->criteria;
 config->criteria = criteria;
 } else {
 /* This is fatal since not following criteria would potentially yield invalid objects */
 ast_log(LOG_ERROR, "Could not create criteria entry of field '%s' with value '%s' for configuration file '%s'\n",
 field, value, filename);
 ao2_ref(config, -1);
 return NULL;
 }
 } else if (!strcasecmp(name, "explicit_name")) {
 ast_free(config->explicit_name);
 config->explicit_name = ast_strdup(value);
 if (ast_strlen_zero(config->explicit_name)) {
 /* This is fatal since it could stop a configuration section from getting applied */
 ast_log(LOG_ERROR, "Could not create explicit name entry of '%s' for configuration file '%s'\n",
 value, filename);
 ao2_ref(config, -1);
 return NULL;
 }
 } else if (!strcasecmp(name, "single_object")) {
 if (ast_strlen_zero(value)) {
 ast_log(LOG_ERROR, "Could not set single object value for configuration file '%s' as the value is empty\n",
 filename);
 ao2_ref(config, -1);
 return NULL;
 }
 config->single_object = ast_true(value);
 } else {
 ast_log(LOG_ERROR, "Unsupported option '%s' used for configuration file '%s'\n", name, filename);
 }
 }

 return config;
}

static void sorcery_config_close(void *data)
{
 struct sorcery_config *config = data;

 ao2_ref(config, -1);
}

static int load_module(void)
{
 if (ast_sorcery_wizard_register(&config_object_wizard)) {
 return AST_MODULE_LOAD_DECLINE;
 }

 return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
 ast_sorcery_wizard_unregister(&config_object_wizard);
 return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "Sorcery Configuration File Object Wizard",
 .support_level = AST_MODULE_SUPPORT_CORE,
 .load = load_module,
 .unload = unload_module,
 .load_pri = AST_MODPRI_REALTIME_DRIVER,
);