X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=blobdiff_plain;f=docs%2Fafb-binding-references.md;h=824c825278b7ac91e79b2ee0c0be639d50c96d62;hb=f3d1f19ae308cc0559728c0ccf6281cbce5ee37c;hp=c266c2ef7a18d6b9ed93e4f6a18cedf8c9cb7ea0;hpb=36c7ab15e79d6b0ff6188b61da1061f36b902f8e;p=src%2Fapp-framework-binder.git diff --git a/docs/afb-binding-references.md b/docs/afb-binding-references.md index c266c2ef..824c8252 100644 --- a/docs/afb-binding-references.md +++ b/docs/afb-binding-references.md @@ -1,723 +1,10 @@ # Binding Reference -## Structure for declaring binding -### struct afb_binding_v2 - -The main structure, of type **afb_binding_v2**, for describing the binding -must be exported under the name **afbBindingV2**. - -This structure is defined as below. - -```C -/* - * Description of the bindings of type version 2 - */ -struct afb_binding_v2 -{ - const char *api; /* api name for the binding */ - const char *specification; /* textual openAPIv3 specification of the binding */ - const char *info; /* some info about the api, can be NULL */ - const struct afb_verb_v2 *verbs; /* array of descriptions of verbs terminated by a NULL name */ - int (*preinit)(); /* callback at load of the binding */ - int (*init)(); /* callback for starting the service */ - void (*onevent)(const char *event, struct json_object *object); /* callback for handling events */ - unsigned noconcurrency: 1; /* avoids concurrent requests to verbs */ -}; -``` - -### struct afb_verb_v2 - -Each verb is described with a structure of type **afb_verb_v2** -defined below: - -```C -/* - * Description of one verb of the API provided by the binding - * This enumeration is valid for bindings of type version 2 - */ -struct afb_verb_v2 -{ - const char *verb; /* name of the verb */ - void (*callback)(struct afb_req req); /* callback function implementing the verb */ - const struct afb_auth *auth; /* required authorization */ - const char *info; /* some info about the verb, can be NULL */ - uint32_t session; /* authorization and session requirements of the verb */ -}; -``` - -The **session** flags is one of the constant defined below: - -- AFB_SESSION_NONE : no flag, synonym to 0 -- AFB_SESSION_LOA_0 : Requires the LOA to be 0 or more, synonym to 0 or AFB_SESSION_NONE -- AFB_SESSION_LOA_1 : Requires the LOA to be 1 or more -- AFB_SESSION_LOA_2 : Requires the LOA to be 2 or more -- AFB_SESSION_LOA_3 : Requires the LOA to be 3 or more -- AFB_SESSION_CHECK : Requires the token to be set and valid -- AFB_SESSION_REFRESH : Implies a token refresh -- AFB_SESSION_CLOSE : Implies cloing the session - -The LOA (Level Of Assurance) is set, by binding, using the function **afb_req_session_set_LOA**. - -### struct afb_auth and enum afb_auth_type - -The structure **afb_auth** is used within verb description to -set security requirements. -The interpretation of the structure depends on the value of the field **type**. - -```C -struct afb_auth -{ - const enum afb_auth_type type; - union { - const char *text; - const unsigned loa; - const struct afb_auth *first; - }; - const struct afb_auth *next; -}; -``` - -The possible values for **type** is defined here: - -```C -/* - * Enum for Session/Token/Assurance middleware. - */ -enum afb_auth_type -{ - afb_auth_No = 0, /** never authorized, no data */ - afb_auth_Token, /** authorized if token valid, no data */ - afb_auth_LOA, /** authorized if LOA greater than data 'loa' */ - afb_auth_Permission, /** authorized if permission 'text' is granted */ - afb_auth_Or, /** authorized if 'first' or 'next' is authorized */ - afb_auth_And, /** authorized if 'first' and 'next' are authorized */ - afb_auth_Not, /** authorized if 'first' is not authorized */ - afb_auth_Yes /** always authorized, no data */ -}; -``` - -Example: - -```C -static const struct afb_auth _afb_auths_v2_monitor[] = { - { .type = afb_auth_Permission, .text = "urn:AGL:permission:monitor:public:set" }, - { .type = afb_auth_Permission, .text = "urn:AGL:permission:monitor:public:get" }, - { .type = afb_auth_Or, .first = &_afb_auths_v2_monitor[1], .next = &_afb_auths_v2_monitor[0] } -}; -``` - -## Functions of class afb_daemon - -The 3 following functions are linked to libsystemd. -They allow use of **sd_event** features and access -to **sd_bus** features. - -```C -/* - * Retrieves the common systemd's event loop of AFB - */ -struct sd_event *afb_daemon_get_event_loop(); - -/* - * Retrieves the common systemd's user/session d-bus of AFB - */ -struct sd_bus *afb_daemon_get_user_bus(); - -/* - * Retrieves the common systemd's system d-bus of AFB - */ -struct sd_bus *afb_daemon_get_system_bus(); -``` - -The 2 following functions are linked to event management. -Broadcasting an event send it to any possible listener. - -```C -/* - * Broadcasts widely the event of 'name' with the data 'object'. - * 'object' can be NULL. - * - * For convenience, the function calls 'json_object_put' for 'object'. - * Thus, in the case where 'object' should remain available after - * the function returns, the function 'json_object_get' shall be used. - * - * Calling this function is only forbidden during preinit. - * - * Returns the count of clients that received the event. - */ -int afb_daemon_broadcast_event(const char *name, struct json_object *object); - -/* - * Creates an event of 'name' and returns it. - * - * Calling this function is only forbidden during preinit. - * - * See afb_event_is_valid to check if there is an error. - */ -struct afb_event afb_daemon_make_event(const char *name); -``` - -The following function is used by logging macros and should normally -not be used. -Instead, you should use the macros: - -- **AFB\_ERROR** -- **AFB\_WARNING** -- **AFB\_NOTICE** -- **AFB\_INFO** -- **AFB\_DEBUG** - -```C -/* - * Send a message described by 'fmt' and following parameters - * to the journal for the verbosity 'level'. - * - * 'file', 'line' and 'func' are indicators of position of the code in source files - * (see macros __FILE__, __LINE__ and __func__). - * - * 'level' is defined by syslog standard: - * EMERGENCY 0 System is unusable - * ALERT 1 Action must be taken immediately - * CRITICAL 2 Critical conditions - * ERROR 3 Error conditions - * WARNING 4 Warning conditions - * NOTICE 5 Normal but significant condition - * INFO 6 Informational - * DEBUG 7 Debug-level messages - */ -void afb_daemon_verbose(int level, const char *file, int line, const char * func, const char *fmt, ...); -``` - -The 2 following functions MUST be used to access data of the bindings. - -```C -/* - * Get the root directory file descriptor. This file descriptor can - * be used with functions 'openat', 'fstatat', ... - */ -int afb_daemon_rootdir_get_fd(); - -/* - * Opens 'filename' within the root directory with 'flags' (see function openat) - * using the 'locale' definition (example: "jp,en-US") that can be NULL. - * Returns the file descriptor or -1 in case of error. - */ -int afb_daemon_rootdir_open_locale(const char *filename, int flags, const char *locale); -``` - -The following function is used to queue jobs. - -```C -/* - * Queue the job defined by 'callback' and 'argument' for being executed asynchronously - * in this thread (later) or in an other thread. - * If 'group' is not NUL, the jobs queued with a same value (as the pointer value 'group') - * are executed in sequence in the order of there submission. - * If 'timeout' is not 0, it represent the maximum execution time for the job in seconds. - * At first, the job is called with 0 as signum and the given argument. - * The job is executed with the monitoring of its time and some signals like SIGSEGV and - * SIGFPE. When a such signal is catched, the job is terminated and re-executed but with - * signum being the signal number (SIGALRM when timeout expired). - * - * Returns 0 in case of success or -1 in case of error. - */ -int afb_daemon_queue_job(void (*callback)(int signum, void *arg), void *argument, void *group, int timeout) -``` - -The following function must be used when a binding depends on other -bindings at its initialization. - -```C -/* - * Tells that it requires the API of "name" to exist - * and if 'initialized' is not null to be initialized. - * Calling this function is only allowed within init. - * Returns 0 in case of success or -1 in case of error. - */ -int afb_daemon_require_api(const char *name, int initialized) -``` - -## Functions of class afb_service - -The following functions allow services to call verbs of other -bindings for themselves. - -```C -/** - * Calls the 'verb' of the 'api' with the arguments 'args' and 'verb' in the name of the binding. - * The result of the call is delivered to the 'callback' function with the 'callback_closure'. - * - * For convenience, the function calls 'json_object_put' for 'args'. - * Thus, in the case where 'args' should remain available after - * the function returns, the function 'json_object_get' shall be used. - * - * The 'callback' receives 3 arguments: - * 1. 'closure' the user defined closure pointer 'callback_closure', - * 2. 'status' a status being 0 on success or negative when an error occured, - * 2. 'result' the resulting data as a JSON object. - * - * @param api The api name of the method to call - * @param verb The verb name of the method to call - * @param args The arguments to pass to the method - * @param callback The to call on completion - * @param callback_closure The closure to pass to the callback - * - * @see also 'afb_req_subcall' - */ -void afb_service_call( - const char *api, - const char *verb, - struct json_object *args, - void (*callback)(void*closure, int status, struct json_object *result), - void *callback_closure); - -/** - * Calls the 'verb' of the 'api' with the arguments 'args' and 'verb' in the name of the binding. - * 'result' will receive the response. - * - * For convenience, the function calls 'json_object_put' for 'args'. - * Thus, in the case where 'args' should remain available after - * the function returns, the function 'json_object_get' shall be used. - * - * @param api The api name of the method to call - * @param verb The verb name of the method to call - * @param args The arguments to pass to the method - * @param result Where to store the result - should call json_object_put on it - - * - * @returns 0 in case of success or a negative value in case of error. - * - * @see also 'afb_req_subcall' - */ -int afb_service_call_sync( - const char *api, - const char *verb, - struct json_object *args, - struct json_object **result); -``` - -## Functions of class afb_event - -This function checks whether the event is valid. -It must be used when creating events. - -```C -/* - * Checks wether the 'event' is valid or not. - * - * Returns 0 if not valid or 1 if valid. - */ -int afb_event_is_valid(struct afb_event event); -``` - -The two following functions are used to broadcast or push -event with its data. - -```C -/* - * Broadcasts widely the 'event' with the data 'object'. - * 'object' can be NULL. - * - * For convenience, the function calls 'json_object_put' for 'object'. - * Thus, in the case where 'object' should remain available after - * the function returns, the function 'json_object_get' shall be used. - * - * Returns the count of clients that received the event. - */ -int afb_event_broadcast(struct afb_event event, struct json_object *object); - -/* - * Pushes the 'event' with the data 'object' to its observers. - * 'object' can be NULL. - * - * For convenience, the function calls 'json_object_put' for 'object'. - * Thus, in the case where 'object' should remain available after - * the function returns, the function 'json_object_get' shall be used. - * - * Returns the count of clients that received the event. - */ -int afb_event_push(struct afb_event event, struct json_object *object); -``` - -The following function destiys the event. - -```C -/* - * Drops the data associated to the 'event' - * After calling this function, the event - * MUST NOT BE USED ANYMORE. - */ -void afb_event_drop(struct afb_event event); -``` - -This function allows to retrieve the exact name of the event. - -```C -/* - * Gets the name associated to the 'event'. - */ -const char *afb_event_name(struct afb_event event); -``` - -## Functions of class afb_req - -This function checks the validity of the **req**. - -```C -/* - * Checks wether the request 'req' is valid or not. - * - * Returns 0 if not valid or 1 if valid. - */ -int afb_req_is_valid(struct afb_req req); -``` - -The following functions retrieves parameters of the request. - -```C -/* - * Gets from the request 'req' the argument of 'name'. - * Returns a PLAIN structure of type 'struct afb_arg'. - * When the argument of 'name' is not found, all fields of result are set to NULL. - * When the argument of 'name' is found, the fields are filled, - * in particular, the field 'result.name' is set to 'name'. - * - * There is a special name value: the empty string. - * The argument of name "" is defined only if the request was made using - * an HTTP POST of Content-Type "application/json". In that case, the - * argument of name "" receives the value of the body of the HTTP request. - */ -struct afb_arg afb_req_get(struct afb_req req, const char *name); - -/* - * Gets from the request 'req' the string value of the argument of 'name'. - * Returns NULL if when there is no argument of 'name'. - * Returns the value of the argument of 'name' otherwise. - * - * Shortcut for: afb_req_get(req, name).value - */ -const char *afb_req_value(struct afb_req req, const char *name); - -/* - * Gets from the request 'req' the path for file attached to the argument of 'name'. - * Returns NULL if when there is no argument of 'name' or when there is no file. - * Returns the path of the argument of 'name' otherwise. - * - * Shortcut for: afb_req_get(req, name).path - */ -const char *afb_req_path(struct afb_req req, const char *name); - -/* - * Gets from the request 'req' the json object hashing the arguments. - * The returned object must not be released using 'json_object_put'. - */ -struct json_object *afb_req_json(struct afb_req req); -``` - -The following functions emit the reply to the request. - -```C -/* - * Sends a reply of kind success to the request 'req'. - * The status of the reply is automatically set to "success". - * Its send the object 'obj' (can be NULL) with an - * informationnal comment 'info (can also be NULL). - * - * For convenience, the function calls 'json_object_put' for 'obj'. - * Thus, in the case where 'obj' should remain available after - * the function returns, the function 'json_object_get' shall be used. - */ -void afb_req_success(struct afb_req req, struct json_object *obj, const char *info); - -/* - * Same as 'afb_req_success' but the 'info' is a formatting - * string followed by arguments. - * - * For convenience, the function calls 'json_object_put' for 'obj'. - * Thus, in the case where 'obj' should remain available after - * the function returns, the function 'json_object_get' shall be used. - */ -void afb_req_success_f(struct afb_req req, struct json_object *obj, const char *info, ...); - -/* - * Same as 'afb_req_success_f' but the arguments to the format 'info' - * are given as a variable argument list instance. - * - * For convenience, the function calls 'json_object_put' for 'obj'. - * Thus, in the case where 'obj' should remain available after - * the function returns, the function 'json_object_get' shall be used. - */ -void afb_req_success_v(struct afb_req req, struct json_object *obj, const char *info, va_list args); - -/* - * Sends a reply of kind failure to the request 'req'. - * The status of the reply is set to 'status' and an - * informationnal comment 'info' (can also be NULL) can be added. - * - * Note that calling afb_req_fail("success", info) is equivalent - * to call afb_req_success(NULL, info). Thus even if possible it - * is strongly recommended to NEVER use "success" for status. - */ -void afb_req_fail(struct afb_req req, const char *status, const char *info); - -/* - * Same as 'afb_req_fail' but the 'info' is a formatting - * string followed by arguments. - */ -void afb_req_fail_f(struct afb_req req, const char *status, const char *info, ...); - -/* - * Same as 'afb_req_fail_f' but the arguments to the format 'info' - * are given as a variable argument list instance. - */ -void afb_req_fail_v(struct afb_req req, const char *status, const char *info, va_list args); -``` - -The following functions handle the session data. - -```C -/* - * Gets the pointer stored by the binding for the session of 'req'. - * When the binding has not yet recorded a pointer, NULL is returned. - */ -void *afb_req_context_get(struct afb_req req); - -/* - * Stores for the binding the pointer 'context' to the session of 'req'. - * The function 'free_context' will be called when the session is closed - * or if binding stores an other pointer. - */ -void afb_req_context_set(struct afb_req req, void *context, void (*free_context)(void*)); - -/* - * Gets the pointer stored by the binding for the session of 'req'. - * If the stored pointer is NULL, indicating that no pointer was - * already stored, afb_req_context creates a new context by calling - * the function 'create_context' and stores it with the freeing function - * 'free_context'. - */ -void *afb_req_context(struct afb_req req, void *(*create_context)(), void (*free_context)(void*)); - -/* - * Frees the pointer stored by the binding for the session of 'req' - * and sets it to NULL. - * - * Shortcut for: afb_req_context_set(req, NULL, NULL) - */ -void afb_req_context_clear(struct afb_req req); - -/* - * Closes the session associated with 'req' - * and delete all associated contexts. - */ -void afb_req_session_close(struct afb_req req); - -/* - * Sets the level of assurance of the session of 'req' - * to 'level'. The effect of this function is subject of - * security policies. - * Returns 1 on success or 0 if failed. - */ -int afb_req_session_set_LOA(struct afb_req req, unsigned level); -``` - -The 4 following functions must be used for asynchronous handling requests. - -```C -/* - * Adds one to the count of references of 'req'. - * This function MUST be called by asynchronous implementations - * of verbs if no reply was sent before returning. - */ -void afb_req_addref(struct afb_req req); - -/* - * Substracts one to the count of references of 'req'. - * This function MUST be called by asynchronous implementations - * of verbs after sending the asynchronous reply. - */ -void afb_req_unref(struct afb_req req); - -/* - * Stores 'req' on heap for asynchronous use. - * Returns a handler to the stored 'req' or NULL on memory depletion. - * The count of reference to 'req' is incremented on success - * (see afb_req_addref). - */ -struct afb_stored_req *afb_req_store(struct afb_req req); - -/* - * Retrieves the afb_req stored at 'sreq'. - * Returns the stored request. - * The count of reference is UNCHANGED, thus, the - * function 'afb_req_unref' should be called on the result - * after that the asynchronous reply if sent. - */ -struct afb_req afb_req_unstore(struct afb_stored_req *sreq); -``` - -The two following functions are used to associate client with events -(subscription). - -```C -/* - * Establishes for the client link identified by 'req' a subscription - * to the 'event'. - * Returns 0 in case of successful subscription or -1 in case of error. - */ -int afb_req_subscribe(struct afb_req req, struct afb_event event); - -/* - * Revokes the subscription established to the 'event' for the client - * link identified by 'req'. - * Returns 0 in case of successful subscription or -1 in case of error. - */ -int afb_req_unsubscribe(struct afb_req req, struct afb_event event); -``` - -The following functions must be used to make request in the name of the -client (with its permissions). - -```C -/* - * Makes a call to the method of name 'api' / 'verb' with the object 'args'. - * This call is made in the context of the request 'req'. - * On completion, the function 'callback' is invoked with the - * 'closure' given at call and two other parameters: 'iserror' and 'result'. - * 'status' is 0 on success or negative when on an error reply. - * 'result' is the json object of the reply, you must not call json_object_put - * on the result. - * - * For convenience, the function calls 'json_object_put' for 'args'. - * Thus, in the case where 'args' should remain available after - * the function returns, the function 'json_object_get' shall be used. - * - * See also: - * - 'afb_req_subcall_req' that is convenient to keep request alive automatically. - * - 'afb_req_subcall_sync' the synchronous version - */ -void afb_req_subcall( - struct afb_req req, - const char *api, - const char *verb, - struct json_object *args, - void (*callback)(void *closure, int status, struct json_object *result), - void *closure); - -/* - * Makes a call to the method of name 'api' / 'verb' with the object 'args'. - * This call is made in the context of the request 'req'. - * On completion, the function 'callback' is invoked with the - * original request 'req', the 'closure' given at call and two - * other parameters: 'iserror' and 'result'. - * 'status' is 0 on success or negative when on an error reply. - * 'result' is the json object of the reply, you must not call json_object_put - * on the result. - * - * For convenience, the function calls 'json_object_put' for 'args'. - * Thus, in the case where 'args' should remain available after - * the function returns, the function 'json_object_get' shall be used. - * - * See also: - * - 'afb_req_subcall' that doesn't keep request alive automatically. - * - 'afb_req_subcall_sync' the synchronous version - */ -static inline void afb_req_subcall_req(struct afb_req req, const char *api, const char *verb, struct json_object *args, void (*callback)(void *closure, int iserror, struct json_object *result, struct afb_req req), void *closure) -{ - req.itf->subcall_req(req.closure, api, verb, args, callback, closure); -} - -/* - * Makes a call to the method of name 'api' / 'verb' with the object 'args'. - * This call is made in the context of the request 'req'. - * This call is synchronous, it waits untill completion of the request. - * It returns 0 on success or a negative value on error answer. - * The object pointed by 'result' is filled and must be released by the caller - * after its use by calling 'json_object_put'. - * - * For convenience, the function calls 'json_object_put' for 'args'. - * Thus, in the case where 'args' should remain available after - * the function returns, the function 'json_object_get' shall be used. - * - * See also: - * - 'afb_req_subcall_req' that is convenient to keep request alive automatically. - * - 'afb_req_subcall' that doesn't keep request alive automatically. - */ -int afb_req_subcall_sync( - struct afb_req req, - const char *api, - const char *verb, - struct json_object *args, - struct json_object **result); -``` - -The following function is used by logging macros and should normally -not be used. -Instead, you should use the macros: - -- **AFB_REQ_ERROR** -- **AFB_REQ_WARNING** -- **AFB_REQ_NOTICE** -- **AFB_REQ_INFO** -- **AFB_REQ_DEBUG** - -```C -/* - * Send associated to 'req' a message described by 'fmt' and following parameters - * to the journal for the verbosity 'level'. - * - * 'file', 'line' and 'func' are indicators of position of the code in source files - * (see macros __FILE__, __LINE__ and __func__). - * - * 'level' is defined by syslog standard: - * EMERGENCY 0 System is unusable - * ALERT 1 Action must be taken immediately - * CRITICAL 2 Critical conditions - * ERROR 3 Error conditions - * WARNING 4 Warning conditions - * NOTICE 5 Normal but significant condition - * INFO 6 Informational - * DEBUG 7 Debug-level messages - */ -void afb_req_verbose(struct afb_req req, int level, const char *file, int line, const char * func, const char *fmt, ...); -``` - -The function below allows a binding to check whether a client -has a permission of not. - -```C - -/* - * Check whether the 'permission' is granted or not to the client - * identified by 'req'. - * - * Returns 1 if the permission is granted or 0 otherwise. - */ -int afb_req_has_permission(struct afb_req req, const char *permission); -``` - -## Logging macros - -The following macros must be used for logging: - -```C -AFB_ERROR(fmt,...) -AFB_WARNING(fmt,...) -AFB_NOTICE(fmt,...) -AFB_INFO(fmt,...) -AFB_DEBUG(fmt,...) -``` - -The following macros can be used for logging in the context -of a request **req** of type **afb_req**: - -```C -AFB_REQ_ERROR(req,fmt,...) -AFB_REQ_WARNING(req,fmt,...) -AFB_REQ_NOTICE(req,fmt,...) -AFB_REQ_INFO(req,fmt,...) -AFB_REQ_DEBUG(req,fmt,...) -``` - -By default, the logging macros add file, line and function -indication. + * [Structures and types](reference-v3/types-and-globals.html) + * [Functions of api](reference-v3/func-api.html) + * [Functions of req](reference-v3/func-req.html) + * [Functions of event](reference-v3/func-event.html) + * [Functions of daemon](reference-v3/func-daemon.html) + * [Functions of service](reference-v3/func-service.html) + * [Macros for logging](reference-v3/macro-log.html)