#ifndef __XPC_CONNECTION_H__ #define __XPC_CONNECTION_H__ #ifndef __XPC_INDIRECT__ #error "Please #include instead of this file directly." /* For HeaderDoc. */ #include #endif /* __XPC_INDIRECT__ */ #ifdef __BLOCKS__ __BEGIN_DECLS /*! * @constant XPC_ERROR_CONNECTION_INTERRUPTED * Will be delivered to the connection's event handler if the remote service * exited. The connection is still live even in this case, and resending a * message will cause the service to be launched on-demand. This error serves * as a client's indication that it should resynchronize any state that it had * given the service. * * Any messages in the queue to be sent will be unwound and canceled when this * error occurs. In the case where a message waiting to be sent has a reply * handler, that handler will be invoked with this error. In the context of the * reply handler, this error indicates that a reply to the message will never * arrive. * * Messages that do not have reply handlers associated with them will be * silently disposed of. This error will only be given to peer connections. */ #define XPC_ERROR_CONNECTION_INTERRUPTED \ XPC_GLOBAL_OBJECT(_xpc_error_connection_interrupted) __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT struct _xpc_dictionary_s _xpc_error_connection_interrupted; /*! * @constant XPC_ERROR_CONNECTION_INVALID * Will be delivered to the connection's event handler if the named service * provided to xpc_connection_create() could not be found in the XPC service * namespace. The connection is useless and should be disposed of. * * Any messages in the queue to be sent will be unwound and canceled when this * error occurs, similarly to the behavior when XPC_ERROR_CONNECTION_INTERRUPTED * occurs. The only difference is that the XPC_ERROR_CONNECTION_INVALID will be * given to outstanding reply handlers and the connection's event handler. * * This error may be given to any type of connection. */ #define XPC_ERROR_CONNECTION_INVALID \ XPC_GLOBAL_OBJECT(_xpc_error_connection_invalid) __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT struct _xpc_dictionary_s _xpc_error_connection_invalid; /*! * @constant XPC_ERROR_TERMINATION_IMMINENT * This error will be delivered to a peer connection's event handler when the * XPC runtime has determined that the program should exit and that all * outstanding transactions must be wound down, and no new transactions can be * opened. * * After this error has been delivered to the event handler, no more messages * will be received by the connection. The runtime will still attempt to deliver * outgoing messages, but this error should be treated as an indication that * the program will exit very soon, and any outstanding business over the * connection should be wrapped up as quickly as possible and the connection * canceled shortly thereafter. * * This error will only be delivered to peer connections received through a * listener or the xpc_main() event handler. */ #define XPC_ERROR_TERMINATION_IMMINENT \ XPC_GLOBAL_OBJECT(_xpc_error_termination_imminent) __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT struct _xpc_dictionary_s _xpc_error_termination_imminent; /*! * @constant XPC_CONNECTION_MACH_SERVICE_LISTENER * Passed to xpc_connection_create_mach_service(). This flag indicates that the * caller is the listener for the named service. This flag may only be passed * for services which are advertised in the process' launchd.plist(5). You may * not use this flag to dynamically add services to the Mach bootstrap * namespace. */ #define XPC_CONNECTION_MACH_SERVICE_LISTENER (1 << 0) /*! * @constant XPC_CONNECTION_MACH_SERVICE_PRIVILEGED * Passed to xpc_connection_create_mach_service(). This flag indicates that the * job advertising the service name in its launchd.plist(5) should be in the * privileged Mach bootstrap. This is typically accomplished by placing your * launchd.plist(5) in /Library/LaunchDaemons. If specified alongside the * XPC_CONNECTION_MACH_SERVICE_LISTENER flag, this flag is a no-op. */ #define XPC_CONNECTION_MACH_SERVICE_PRIVILEGED (1 << 1) /*! * @typedef xpc_finalizer_f * A function that is invoked when a connection is being torn down and its * context needs to be freed. It is not safe to reference the connection from * within this function. * * @param value * The context object that is to be disposed of. */ typedef void (*xpc_finalizer_t)(void *value); /*! * @function xpc_connection_create * Creates a new connection object. * * @param name * If non-NULL, the name of the service with which to connect. The returned * connection will be a peer. * * If NULL, an anonymous listener connection will be created. You can embed the * ability to create new peer connections in an endpoint, which can be inserted * into a message and sent to another process . * * @param targetq * The GCD queue to which the event handler block will be submitted. This * parameter may be NULL, in which case the connection's target queue will be * libdispatch's default target queue, defined as DISPATCH_TARGET_QUEUE_DEFAULT. * The target queue may be changed later with a call to * xpc_connection_set_target_queue(). * * @result * A new connection object. The caller is responsible for disposing of the * returned object with {@link xpc_release} when it is no longer needed. * * @discussion * This method will succeed even if the named service does not exist. This is * because the XPC namespace is not queried for the service name until * the first call to xpc_connection_resume(). * * XPC connections, like dispatch sources, are returned in a suspended state, so * you must call {@link xpc_connection_resume()} in order to begin receiving * events from the connection. Also like dispatch sources, connections must be * resumed in order to be safely released. It is a programming error to release * a suspended connection. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_WARN_RESULT XPC_MALLOC XPC_RETURNS_RETAINED xpc_connection_t xpc_connection_create(const char *name, dispatch_queue_t targetq); /*! * @function xpc_connection_create_mach_service * Creates a new connection object representing a Mach service. * * @param name * The name of the remote service with which to connect. The service name must * exist in a Mach bootstrap that is accessible to the process and be advertised * in a launchd.plist. * * @param targetq * The GCD queue to which the event handler block will be submitted. This * parameter may be NULL, in which case the connection's target queue will be * libdispatch's default target queue, defined as DISPATCH_TARGET_QUEUE_DEFAULT. * The target queue may be changed later with a call to * xpc_connection_set_target_queue(). * * @param flags * Additional attributes with which to create the connection. * * @result * A new connection object. * * @discussion * If the XPC_CONNECTION_MACH_SERVICE_LISTENER flag is given to this method, * then the connection returned will be a listener connection. Otherwise, a peer * connection will be returned. See the documentation for * {@link xpc_connection_set_event_handler()} for the semantics of listener * connections versus peer connections. * * This method will succeed even if the named service does not exist. This is * because the Mach namespace is not queried for the service name until the * first call to {@link xpc_connection_resume()}. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL1 XPC_WARN_RESULT XPC_MALLOC XPC_RETURNS_RETAINED xpc_connection_t xpc_connection_create_mach_service(const char *name, dispatch_queue_t targetq, uint64_t flags); /*! * @function xpc_connection_create_from_endpoint * Creates a new connection from the given endpoint. * * @param endpoint * The endpoint from which to create the new connection. * * @result * A new peer connection to the listener represented by the given endpoint. * * The same responsibilities of setting an event handler and resuming the * connection after calling xpc_connection_create() apply to the connection * returned by this API. Since the connection yielded by this API is not * associated with a name (and therefore is not rediscoverable), this connection * will receive XPC_ERROR_CONNECTION_INVALID if the listening side crashes, * exits or cancels the listener connection. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL XPC_WARN_RESULT XPC_MALLOC XPC_RETURNS_RETAINED xpc_connection_t xpc_connection_create_from_endpoint(xpc_endpoint_t endpoint); /*! * @function xpc_connection_set_target_queue * Sets the target queue of the given connection. * * @param connection * The connection object which is to be manipulated. * * @param targetq * The GCD queue to which the event handler block will be submitted. This * parameter may be NULL, in which case the connection's target queue will be * libdispatch's default target queue, defined as DISPATCH_TARGET_QUEUE_DEFAULT. * * @discussion * Setting the target queue is asynchronous and non-preemptive and therefore * this method will not interrupt the execution of an already-running event * handler block. Setting the target queue may be likened to issuing a barrier * to the connection which does the actual work of changing the target queue. * * The XPC runtime guarantees this non-preemptiveness even for concurrent target * queues. If the target queue is a concurrent queue, then XPC still guarantees * that there will never be more than one invocation of the connection's event * handler block executing concurrently. If you wish to process events * concurrently, you can dispatch_async(3) to a concurrent queue from within * the event handler. * * IMPORTANT: When called from within the event handler block, * dispatch_get_current_queue(3) is NOT guaranteed to return a pointer to the * queue set with this method. * * Despite this seeming inconsistency, the XPC runtime guarantees that, when the * target queue is a serial queue, the event handler block will execute * synchonously with respect to other blocks submitted to that same queue. When * the target queue is a concurrent queue, the event handler block may run * concurrently with other blocks submitted to that queue, but it will never run * concurrently with other invocations of itself for the same connection, as * discussed previously. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL1 void xpc_connection_set_target_queue(xpc_connection_t connection, dispatch_queue_t targetq); /*! * @function xpc_connection_set_event_handler * Sets the event handler block for the connection. * * @param connection * The connection object which is to be manipulated. * * @param handler * The event handler block. * * @discussion * Setting the event handler is asynchronous and non-preemptive, and therefore * this method will not interrupt the execution of an already-running event * handler block. If the event handler is executing at the time of this call, it * will finish, and then the connection's event handler will be changed before * the next invocation of the event handler. The XPC runtime guarantees this * non-preemptiveness even for concurrent target queues. * * Connection event handlers are non-reentrant, so it is safe to call * xpc_connection_set_event_handler() from within the event handler block. * * The event handler's execution should be treated as a barrier to all * connection activity. When it is executing, the connection will not attempt to * send or receive messages, including reply messages. Thus, it is not safe to * call xpc_connection_send_message_with_reply_sync() on the connection from * within the event handler. * * You do not hold a reference on the object received as the event handler's * only argument. Regardless of the type of object received, it is safe to call * xpc_retain() on the object to obtain a reference to it. * * A connection may receive different events depending upon whether it is a * listener or not. Any connection may receive an error in its event handler. * But while normal connections may receive messages in addition to errors, * listener connections will receive connections and and not messages. * * Connections received by listeners are equivalent to those returned by * xpc_connection_create() with a non-NULL name argument and a NULL targetq * argument with the exception that you do not hold a reference on them. * You must set an event handler and resume the connection. If you do not wish * to accept the connection, you may simply call xpc_connection_cancel() on it * and return. The runtime will dispose of it for you. * * If there is an error in the connection, this handler will be invoked with the * error dictionary as its argument. This dictionary will be one of the well- * known XPC_ERROR_* dictionaries. * * Regardless of the type of event, ownership of the event object is NOT * implicitly transferred. Thus, the object will be released and deallocated at * some point in the future after the event handler returns. If you wish the * event's lifetime to persist, you must retain it with xpc_retain(). * * Connections received through the event handler will be released and * deallocated after the connection has gone invalid and delivered that event to * its event handler. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL void xpc_connection_set_event_handler(xpc_connection_t connection, xpc_handler_t handler); /*! * @function xpc_connection_suspend * Suspends the connection so that the event handler block will not fire and * that the connection will not attempt to send any messages it has in its * queue. All calls to xpc_connection_suspend() must be balanced with calls to * xpc_connection_resume() before releasing the last reference to the * connection. * * @param connection * The connection object which is to be manipulated. * * @discussion * Suspension is asynchronous and non-preemptive, and therefore this method will * not interrupt the execution of an already-running event handler block. If * the event handler is executing at the time of this call, it will finish, and * then the connection will be suspended before the next scheduled invocation * of the event handler. The XPC runtime guarantees this non-preemptiveness even * for concurrent target queues. * * Connection event handlers are non-reentrant, so it is safe to call * xpc_connection_suspend() from within the event handler block. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL void xpc_connection_suspend(xpc_connection_t connection); /*! * @function xpc_connection_resume * Resumes the connection. Connections start in a suspended state, so you must * call xpc_connection_resume() on a connection before it will send or receive * any messages. * * @param connection * The connection object which is to be manipulated. * * @discussion * In order for a connection to become live, every call to * xpc_connection_suspend() must be balanced with a call to * xpc_connection_resume() after the initial call to xpc_connection_resume(). * After the initial resume of the connection, calling xpc_connection_resume() * more times than xpc_connection_suspend() has been called is considered an * error. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL void xpc_connection_resume(xpc_connection_t connection); /*! * @function xpc_connection_send_message * Sends a message over the connection to the destination service. * * @param connection * The connection over which the message shall be sent. * * @param message * The message to send. This must be a dictionary object. This dictionary is * logically copied by the connection, so it is safe to modify the dictionary * after this call. * * @discussion * Messages are delivered in FIFO order. This API is safe to call from multiple * GCD queues. There is no indication that a message was delivered successfully. * This is because even once the message has been successfully enqueued on the * remote end, there are no guarantees about when the runtime will dequeue the * message and invoke the other connection's event handler block. * * If this API is used to send a message that is in reply to another message, * there is no guarantee of ordering between the invocations of the connection's * event handler and the reply handler for that message, even if they are * targeted to the same queue. * * After extensive study, we have found that clients who are interested in * the state of the message on the server end are typically holding open * transactions related to that message. And the only reliable way to track the * lifetime of that transaction is at the protocol layer. So the server should * send a reply message, which upon receiving, will cause the client to close * its transaction. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL void xpc_connection_send_message(xpc_connection_t connection, xpc_object_t message); /*! * @function xpc_connection_send_barrier * Issues a barrier against the connection's message-send activity. * * @param connection * The connection against which the barrier is to be issued. * * @param barrier * The barrier block to issue. This barrier prevents concurrent message-send * activity on the connection. No messages will be sent while the barrier block * is executing. * * @discussion * XPC guarantees that, even if the connection's target queue is a concurrent * queue, there are no other messages being sent concurrently while the barrier * block is executing. XPC does not guarantee that the reciept of messages * (either through the connection's event handler or through reply handlers) * will be suspended while the barrier is executing. * * A barrier is issued relative to the message-send queue. Thus, if you call * xpc_connection_send_message() five times and then call * xpc_connection_send_barrier(), the barrier will be invoked after the fifth * message has been sent and its memory disposed of. You may safely cancel a * connection from within a barrier block. * * If a barrier is issued after sending a message which expects a reply, the * behavior is the same as described above. The receipt of a reply message will * not influence when the barrier runs. * * A barrier block can be useful for throttling resource consumption on the * connected side of a connection. For example, if your connection sends many * large messages, you can use a barrier to limit the number of messages that * are inflight at any given time. This can be particularly useful for messages * that contain kernel resources (like file descriptors) which have a system- * wide limit. * * If a barrier is issued on a canceled connection, it will be invoked * immediately. If a connection has been canceled and still has outstanding * barriers, those barriers will be invoked as part of the connection's * unwinding process. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL void xpc_connection_send_barrier(xpc_connection_t connection, dispatch_block_t barrier); /*! * @function xpc_connection_send_message_with_reply * Sends a message over the connection to the destination service and associates * a handler to be invoked when the remote service sends a reply message. * * @param connection * The connection over which the message shall be sent. * * @param message * The message to send. This must be a dictionary object. * * @param replyq * The GCD queue to which the reply handler will be submitted. This may be a * concurrent queue. * * @param handler * The handler block to invoke when a reply to the message is received from * the connection. If the remote service exits prematurely before the reply was * received, the XPC_ERROR_CONNECTION_INTERRUPTED error will be returned. * If the connection went invalid before the message could be sent, the * XPC_ERROR_CONNECTION_INVALID error will be returned. * * @discussion * If the given GCD queue is a concurrent queue, XPC cannot guarantee that there * will not be multiple reply handlers being invoked concurrently. XPC does not * guarantee any ordering for the invocation of reply handers. So if multiple * messages are waiting for replies and the connection goes invalid, there is no * guarantee that the reply handlers will be invoked in FIFO order. Similarly, * XPC does not guarantee that reply handlers will not run concurrently with * the connection's event handler in the case that the reply queue and the * connection's target queue are the same concurrent queue. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL1 XPC_NONNULL2 XPC_NONNULL4 void xpc_connection_send_message_with_reply(xpc_connection_t connection, xpc_object_t message, dispatch_queue_t replyq, xpc_handler_t handler); /*! * @function xpc_connection_send_message_with_reply_sync * Sends a message over the connection and blocks the caller until a reply is * received. * * @param connection * The connection over which the message shall be sent. * * @param message * The message to send. This must be a dictionary object. * * @result * The message that the remote service sent in reply to the original message. * If the remote service exits prematurely before the reply was received, the * XPC_ERROR_CONNECTION_INTERRUPTED error will be returned. If the connection * went invalid before the message could be sent, the * XPC_ERROR_CONNECTION_INVALID error will be returned. * * You are responsible for releasing the returned object. * * @discussion * This API is primarily for transitional purposes. Its implementation is * conceptually equivalent to calling xpc_connection_send_message_with_reply() * and then immediately blocking the calling thread on a semaphore and * signaling the semaphore from the reply block. * * Be judicious about your use of this API. It can block indefinitely, so if you * are using it to implement an API that can be called from the main thread, you * may wish to consider allowing the API to take a queue and callback block so * that results may be delivered asynchrously if possible. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL XPC_WARN_RESULT XPC_RETURNS_RETAINED xpc_object_t xpc_connection_send_message_with_reply_sync(xpc_connection_t connection, xpc_object_t message); /*! * @function xpc_connection_cancel * Cancels the connection and ensures that its event handler will not fire * again. After this call, any messages that have not yet been sent will be * discarded, and the connection will be unwound. If there are messages that are * awaiting replies, they will have their reply handlers invoked with the * XPC_ERROR_CONNECTION_INVALID error. * * @param connection * The connection object which is to be manipulated. * * @discussion * Cancellation is asynchronous and non-preemptive and therefore this method * will not interrupt the execution of an already-running event handler block. * If the event handler is executing at the time of this call, it will finish, * and then the connection will be canceled, causing a final invocation of the * event handler to be scheduled with the XPC_ERROR_CONNECTION_INVALID error. * After that invocation, there will be no further invocations of the event * handler. * * The XPC runtime guarantees this non-preemptiveness even for concurrent target * queues. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL void xpc_connection_cancel(xpc_connection_t connection); /*! * @function xpc_connection_get_name * Returns the name of the service with which the connections was created. * * @param connection * The connection object which is to be examined. * * @result * The name of the remote service. If you obtained the connection through an * invocation of another connection's event handler, NULL is returned. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL XPC_WARN_RESULT const char * xpc_connection_get_name(xpc_connection_t connection); /*! * @function xpc_connection_get_euid * Returns the EUID of the remote peer. * * @param connection * The connection object which is to be examined. * * @result * The EUID of the remote peer at the time the connection was made. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL XPC_WARN_RESULT uid_t xpc_connection_get_euid(xpc_connection_t connection); /*! * @function xpc_connection_get_egid * Returns the EGID of the remote peer. * * @param connection * The connection object which is to be examined. * * @result * The EGID of the remote peer at the time the connection was made. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL XPC_WARN_RESULT gid_t xpc_connection_get_egid(xpc_connection_t connection); /*! * @function xpc_connection_get_pid * Returns the PID of the remote peer. * * @param connection * The connection object which is to be examined. * * @result * The PID of the remote peer. * * @discussion * A given PID is not guaranteed to be unique across an entire boot cycle. * Great care should be taken when dealing with this information, as it can go * stale after the connection is established. Mac OS X recycles PIDs, and * therefore another process could spawn and claim the PID before a message is * actually received from the connection. * * XPC will deliver an error to your event handler if the remote process goes * away, but there are no guarantees as to the timing of this notification's * delivery either at the kernel layer or at the XPC layer. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL XPC_WARN_RESULT pid_t xpc_connection_get_pid(xpc_connection_t connection); /*! * @function xpc_connection_get_asid * Returns the audit session identifier of the remote peer. * * @param connection * The connection object which is to be examined. * * @result * The audit session ID of the remote peer at the time the connection was made. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL XPC_WARN_RESULT au_asid_t xpc_connection_get_asid(xpc_connection_t connection); /*! * @function xpc_connection_set_context * Sets context on an connection. * * @param connection * The connection which is to be manipulated. * * @param context * The context to associate with the connection. * * @discussion * If you must manage the memory of the context object, you must set a finalizer * to dispose of it. If this method is called on a connection which already has * context associated with it, the finalizer will NOT be invoked. The finalizer * is only invoked when the connection is being deallocated. * * It is recommended that, instead of changing the actual context pointer * associated with the object, you instead change the state of the context * object itself. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL1 void xpc_connection_set_context(xpc_connection_t connection, void *context); /*! * @function xpc_connection_get_context * Returns the context associated with the connection. * * @param connection * The connection which is to be examined. * * @result * The context associated with the connection. NULL if there has been no context * associated with the object. */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL_ALL XPC_WARN_RESULT void * xpc_connection_get_context(xpc_connection_t connection); /*! * @function xpc_connection_set_finalizer_f * Sets the finalizer for the given connection. * * @param connection * The connection on which to set the finalizer. * * @param finalizer * The function that will be invoked when the connection's retain count has * dropped to zero and is being torn down. * * @discussion * For many uses of context objects, this API allows for a convenient shorthand * for freeing them. For example, for a context object allocated with malloc(3): * * xpc_connection_set_finalizer_f(object, free); */ __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_5_0) XPC_EXPORT XPC_NONNULL1 void xpc_connection_set_finalizer_f(xpc_connection_t connection, xpc_finalizer_t finalizer); __END_DECLS #endif /* __BLOCKS__ */ #endif /* __XPC_CONNECTION_H__ */