[lttng-tools.git] / src / bin / lttng-sessiond / notification-thread-internal.h

/*
 * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#ifndef NOTIFICATION_THREAD_INTERNAL_H
#define NOTIFICATION_THREAD_INTERNAL_H

#include <common/compat/socket.h>
#include <common/credentials.h>
#include <lttng/notification/channel-internal.h>
#include <lttng/ref-internal.h>
#include <stdbool.h>
#include <unistd.h>
#include <urcu/rculfhash.h>
#include <urcu/ref.h>
#include <urcu/call-rcu.h>
#include "notification-thread.h"

struct lttng_evaluation;
struct notification_thread_handle;

struct channel_key {
	uint64_t key;
	enum lttng_domain_type domain;
};

struct session_info {
	struct lttng_ref ref;
	char *name;
	uid_t uid;
	gid_t gid;
	/*
	 * Hashtable containing back-refs (weak) to all channels in this session.
	 * The hashtable's key is a hash of (struct channel_key) and
	 * the value is of type (struct channel_info *).
	 */
	struct cds_lfht *channel_infos_ht;
	struct lttng_session_trigger_list *trigger_list;
	/* Node in the notification thread state's sessions_ht. */
	struct cds_lfht_node sessions_ht_node;
	/*
	 * Weak reference to the thread state's sessions_ht. Used for removal on
	 * destruction.
	 */
	struct cds_lfht *sessions_ht;
	uint64_t consumed_data_size;
	struct {
		/* Whether a rotation is ongoing for this session. */
		bool ongoing;
		/* Identifier of the currently ongoing rotation. */
		uint64_t id;
	} rotation;
	/* call_rcu delayed reclaim. */
	struct rcu_head rcu_node;
};

struct channel_info {
	struct channel_key key;
	char *name;
	uint64_t capacity;
	/*
	 * A channel info holds a reference (lttng_ref) on session_info.
	 * session_info, in return, holds a weak reference to the channel.
	 */
	struct session_info *session_info;
	/* Node in the notification thread state's channels_ht. */
	struct cds_lfht_node channels_ht_node;
	/* Node in the session_info's channels_ht. */
	struct cds_lfht_node session_info_channels_ht_node;
	/* call_rcu delayed reclaim. */
	struct rcu_head rcu_node;
};

struct notification_client_list_element {
	struct notification_client *client;
	struct cds_list_head node;
};

/*
 * Thread safety of notification_client and notification_client_list.
 *
 * The notification thread (main thread) and the action executor
 * interact through client lists. Hence, when the action executor
 * thread looks-up the list of clients subscribed to a given
 * condition, it will acquire a reference to the list and lock it
 * while attempting to communicate with the various clients.
 *
 * It is not necessary to reference-count clients as they are guaranteed
 * to be 'alive' if they are present in a list and that list is locked. Indeed,
 * removing references to the client from those subscription lists is part of
 * the work performed on destruction of a client.
 *
 * No provision for other access scenarios are taken into account;
 * this is the bare minimum to make these accesses safe and the
 * notification thread's state is _not_ "thread-safe" in any general
 * sense.
 */
struct notification_client_list {
	pthread_mutex_t lock;
	struct urcu_ref ref;
	const struct lttng_trigger *trigger;
	struct cds_list_head list;
	/* Weak reference to container. */
	struct cds_lfht *notification_trigger_clients_ht;
	struct cds_lfht_node notification_trigger_clients_ht_node;
	/* call_rcu delayed reclaim. */
	struct rcu_head rcu_node;
};

struct notification_client {
	/*
	 * Nests within the notification_client_list lock.
	 *
	 * Protects the outbound communication and the active flag which
	 * is used by both the notification and action executor threads.
	 *
	 * The remaining fields of the object can be used without any
	 * synchronization as they are either immutable (id, creds, version) or
	 * only accessed by the notification thread.
	 */
	pthread_mutex_t lock;
	notification_client_id id;
	int socket;
	/* Client protocol version. */
	uint8_t major, minor;
	uid_t uid;
	gid_t gid;
	/*
	 * Indicates if the credentials and versions of the client have been
	 * checked.
	 */
	bool validated;
	/*
	 * Conditions to which the client's notification channel is subscribed.
	 * List of struct lttng_condition_list_node. The condition member is
	 * owned by the client.
	 */
	struct cds_list_head condition_list;
	struct cds_lfht_node client_socket_ht_node;
	struct cds_lfht_node client_id_ht_node;
	struct {
		/*
		 * If a client's communication is inactive, it means that a
		 * fatal error has occurred (could be either a protocol error or
		 * the socket API returned a fatal error). No further
		 * communication should be attempted; the client is queued for
		 * clean-up.
		 */
		bool active;
		struct {
			/*
			 * During the reception of a message, the reception
			 * buffers' "size" is set to contain the current
			 * message's complete payload.
			 */
			struct lttng_dynamic_buffer buffer;
			/* Bytes left to receive for the current message. */
			size_t bytes_to_receive;
			/* Type of the message being received. */
			enum lttng_notification_channel_message_type msg_type;
			/*
			 * Indicates whether or not credentials are expected
			 * from the client.
			 */
			bool expect_creds;
			/*
			 * Indicates whether or not credentials were received
			 * from the client.
			 */
			bool creds_received;
			/* Only used during credentials reception. */
			lttng_sock_cred creds;
		} inbound;
		struct {
			/*
			 * Indicates whether or not a notification addressed to
			 * this client was dropped because a command reply was
			 * already buffered.
			 *
			 * A notification is dropped whenever the buffer is not
			 * empty.
			 */
			bool dropped_notification;
			/*
			 * Indicates whether or not a command reply is already
			 * buffered. In this case, it means that the client is
			 * not consuming command replies before emitting a new
			 * one. This could be caused by a protocol error or a
			 * misbehaving/malicious client.
			 */
			bool queued_command_reply;
			struct lttng_dynamic_buffer buffer;
		} outbound;
	} communication;
	/* call_rcu delayed reclaim. */
	struct rcu_head rcu_node;
};

enum client_transmission_status {
	CLIENT_TRANSMISSION_STATUS_COMPLETE,
	CLIENT_TRANSMISSION_STATUS_QUEUED,
	/* Communication failure. */
	CLIENT_TRANSMISSION_STATUS_FAIL,
	/* Fatal error. */
	CLIENT_TRANSMISSION_STATUS_ERROR,
};

LTTNG_HIDDEN
bool notification_client_list_get(struct notification_client_list *list);

LTTNG_HIDDEN
void notification_client_list_put(struct notification_client_list *list);

/* Only returns a non-zero value if a fatal error occurred. */
typedef int (*report_client_transmission_result_cb)(
		struct notification_client *client,
		enum client_transmission_status status,
		void *user_data);

LTTNG_HIDDEN
int notification_client_list_send_evaluation(
		struct notification_client_list *list,
		const struct lttng_condition *condition,
		const struct lttng_evaluation *evaluation,
		const struct lttng_credentials *trigger_creds,
		const struct lttng_credentials *source_object_creds,
		report_client_transmission_result_cb client_report,
		void *user_data);

LTTNG_HIDDEN
int notification_thread_client_communication_update(
		struct notification_thread_handle *handle,
		notification_client_id id,
		enum client_transmission_status transmission_status);

#endif /* NOTIFICATION_THREAD_INTERNAL_H */
Commit	Line	Data
8abe313a	1	/*
ab5be9fa	2	* Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
8abe313a	3	*
ab5be9fa	4	* SPDX-License-Identifier: GPL-2.0-only
8abe313a	5	*
8abe313a JG	6	*/
	7
	8	#ifndef NOTIFICATION_THREAD_INTERNAL_H
	9	#define NOTIFICATION_THREAD_INTERNAL_H
	10
f2b3ef9f JG	11	#include <common/compat/socket.h>
	12	#include <common/credentials.h>
	13	#include <lttng/notification/channel-internal.h>
8abe313a	14	#include <lttng/ref-internal.h>
f2b3ef9f	15	#include <stdbool.h>
ae0a823f	16	#include <unistd.h>
f2b3ef9f JG	17	#include <urcu/rculfhash.h>
	18	#include <urcu/ref.h>
	19	#include <urcu/call-rcu.h>
	20	#include "notification-thread.h"
	21
	22	struct lttng_evaluation;
	23	struct notification_thread_handle;
8abe313a JG	24
	25	struct channel_key {
	26	uint64_t key;
	27	enum lttng_domain_type domain;
	28	};
	29
	30	struct session_info {
	31	struct lttng_ref ref;
	32	char *name;
	33	uid_t uid;
	34	gid_t gid;
	35	/*
c7283958	36	* Hashtable containing back-refs (weak) to all channels in this session.
8abe313a JG	37	* The hashtable's key is a hash of (struct channel_key) and
	38	* the value is of type (struct channel_info *).
	39	*/
	40	struct cds_lfht *channel_infos_ht;
ea9a44f0	41	struct lttng_session_trigger_list *trigger_list;
8abe313a JG	42	/* Node in the notification thread state's sessions_ht. */
8abe313a JG	43	struct cds_lfht_node sessions_ht_node;
1eee26c5 JG	44	/*
	45	* Weak reference to the thread state's sessions_ht. Used for removal on
	46	* destruction.
	47	*/
	48	struct cds_lfht *sessions_ht;
e8360425	49	uint64_t consumed_data_size;
51eab943 JG	50	struct {
	51	/* Whether a rotation is ongoing for this session. */
	52	bool ongoing;
	53	/* Identifier of the currently ongoing rotation. */
	54	uint64_t id;
	55	} rotation;
83b934ad MD	56	/* call_rcu delayed reclaim. */
83b934ad MD	57	struct rcu_head rcu_node;
8abe313a JG	58	};
	59
	60	struct channel_info {
	61	struct channel_key key;
	62	char *name;
	63	uint64_t capacity;
	64	/*
	65	* A channel info holds a reference (lttng_ref) on session_info.
	66	* session_info, in return, holds a weak reference to the channel.
	67	*/
	68	struct session_info *session_info;
	69	/* Node in the notification thread state's channels_ht. */
	70	struct cds_lfht_node channels_ht_node;
	71	/* Node in the session_info's channels_ht. */
	72	struct cds_lfht_node session_info_channels_ht_node;
83b934ad MD	73	/* call_rcu delayed reclaim. */
83b934ad MD	74	struct rcu_head rcu_node;
8abe313a JG	75	};
8abe313a JG	76
f2b3ef9f JG	77	struct notification_client_list_element {
	78	struct notification_client *client;
	79	struct cds_list_head node;
	80	};
	81
	82	/*
	83	* Thread safety of notification_client and notification_client_list.
	84	*
	85	* The notification thread (main thread) and the action executor
	86	* interact through client lists. Hence, when the action executor
	87	* thread looks-up the list of clients subscribed to a given
	88	* condition, it will acquire a reference to the list and lock it
	89	* while attempting to communicate with the various clients.
	90	*
	91	* It is not necessary to reference-count clients as they are guaranteed
	92	* to be 'alive' if they are present in a list and that list is locked. Indeed,
	93	* removing references to the client from those subscription lists is part of
	94	* the work performed on destruction of a client.
	95	*
	96	* No provision for other access scenarios are taken into account;
	97	* this is the bare minimum to make these accesses safe and the
	98	* notification thread's state is _not_ "thread-safe" in any general
	99	* sense.
	100	*/
	101	struct notification_client_list {
	102	pthread_mutex_t lock;
	103	struct urcu_ref ref;
	104	const struct lttng_trigger *trigger;
	105	struct cds_list_head list;
	106	/* Weak reference to container. */
	107	struct cds_lfht *notification_trigger_clients_ht;
	108	struct cds_lfht_node notification_trigger_clients_ht_node;
	109	/* call_rcu delayed reclaim. */
	110	struct rcu_head rcu_node;
	111	};
	112
	113	struct notification_client {
6c24d3fd JG	114	/*
	115	* Nests within the notification_client_list lock.
	116	*
	117	* Protects the outbound communication and the active flag which
	118	* is used by both the notification and action executor threads.
	119	*
	120	* The remaining fields of the object can be used without any
	121	* synchronization as they are either immutable (id, creds, version) or
	122	* only accessed by the notification thread.
	123	*/
f2b3ef9f JG	124	pthread_mutex_t lock;
	125	notification_client_id id;
	126	int socket;
	127	/* Client protocol version. */
	128	uint8_t major, minor;
	129	uid_t uid;
	130	gid_t gid;
	131	/*
	132	* Indicates if the credentials and versions of the client have been
	133	* checked.
	134	*/
	135	bool validated;
	136	/*
	137	* Conditions to which the client's notification channel is subscribed.
	138	* List of struct lttng_condition_list_node. The condition member is
	139	* owned by the client.
	140	*/
	141	struct cds_list_head condition_list;
	142	struct cds_lfht_node client_socket_ht_node;
	143	struct cds_lfht_node client_id_ht_node;
	144	struct {
	145	/*
	146	* If a client's communication is inactive, it means that a
	147	* fatal error has occurred (could be either a protocol error or
	148	* the socket API returned a fatal error). No further
	149	* communication should be attempted; the client is queued for
	150	* clean-up.
	151	*/
	152	bool active;
	153	struct {
	154	/*
	155	* During the reception of a message, the reception
	156	* buffers' "size" is set to contain the current
	157	* message's complete payload.
	158	*/
	159	struct lttng_dynamic_buffer buffer;
	160	/* Bytes left to receive for the current message. */
	161	size_t bytes_to_receive;
	162	/* Type of the message being received. */
	163	enum lttng_notification_channel_message_type msg_type;
	164	/*
	165	* Indicates whether or not credentials are expected
	166	* from the client.
	167	*/
	168	bool expect_creds;
	169	/*
	170	* Indicates whether or not credentials were received
	171	* from the client.
	172	*/
	173	bool creds_received;
	174	/* Only used during credentials reception. */
	175	lttng_sock_cred creds;
	176	} inbound;
	177	struct {
	178	/*
	179	* Indicates whether or not a notification addressed to
	180	* this client was dropped because a command reply was
	181	* already buffered.
	182	*
	183	* A notification is dropped whenever the buffer is not
	184	* empty.
	185	*/
	186	bool dropped_notification;
	187	/*
188	* Indicates whether or not a command reply is already
189	* buffered. In this case, it means that the client is
190	* not consuming command replies before emitting a new
191	* one. This could be caused by a protocol error or a
192	* misbehaving/malicious client.
193	*/
194	bool queued_command_reply;
195	struct lttng_dynamic_buffer buffer;
196	} outbound;
197	} communication;
198	/* call_rcu delayed reclaim. */
199	struct rcu_head rcu_node;
200	};
201
dd877ea6 JG	202	enum client_transmission_status {
	203	CLIENT_TRANSMISSION_STATUS_COMPLETE,
	204	CLIENT_TRANSMISSION_STATUS_QUEUED,
	205	/* Communication failure. */
	206	CLIENT_TRANSMISSION_STATUS_FAIL,
	207	/* Fatal error. */
	208	CLIENT_TRANSMISSION_STATUS_ERROR,
	209	};
f2b3ef9f JG	210
	211	LTTNG_HIDDEN
	212	bool notification_client_list_get(struct notification_client_list *list);
	213
	214	LTTNG_HIDDEN
	215	void notification_client_list_put(struct notification_client_list *list);
	216
6c24d3fd	217	/* Only returns a non-zero value if a fatal error occurred. */
f2b3ef9f JG	218	typedef int (*report_client_transmission_result_cb)(
	219	struct notification_client *client,
	220	enum client_transmission_status status,
	221	void *user_data);
	222
	223	LTTNG_HIDDEN
	224	int notification_client_list_send_evaluation(
	225	struct notification_client_list *list,
	226	const struct lttng_condition *condition,
	227	const struct lttng_evaluation *evaluation,
	228	const struct lttng_credentials *trigger_creds,
	229	const struct lttng_credentials *source_object_creds,
	230	report_client_transmission_result_cb client_report,
	231	void *user_data);
	232
	233	LTTNG_HIDDEN
	234	int notification_thread_client_communication_update(
	235	struct notification_thread_handle *handle,
	236	notification_client_id id,
	237	enum client_transmission_status transmission_status);
	238
8abe313a	239	#endif /* NOTIFICATION_THREAD_INTERNAL_H */