[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 <common/payload.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;
};

/*
 * Facilities to carry the different notifications type in the action
 * processing code path.
 */
struct lttng_event_notifier_notification {
	uint64_t tracer_token;
	enum lttng_domain_type type;
	size_t capture_buf_size;
	char *capture_buffer;
};

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;
	struct lttng_condition *condition;
	struct cds_list_head triggers_list;
	struct cds_list_head clients_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_payload payload;
			/* Bytes left to receive for the current message. */
			size_t bytes_to_receive;
			/* FDs left to receive for the current message. */
			int fds_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_payload payload;
		} 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);

/*
 * Takes ownership of the payload if present.
 */
LTTNG_HIDDEN
struct lttng_event_notifier_notification *lttng_event_notifier_notification_create(
		uint64_t tracer_token,
		enum lttng_domain_type domain,
		char *payload,
		size_t payload_size);

LTTNG_HIDDEN
void lttng_event_notifier_notification_destroy(
		struct lttng_event_notifier_notification *event_notifier_notification);

#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>
f2b3ef9f JG	12	#include <common/credentials.h>
882093ee	13	#include <common/payload.h>
f2b3ef9f	14	#include <lttng/notification/channel-internal.h>
8abe313a	15	#include <lttng/ref-internal.h>
f2b3ef9f	16	#include <stdbool.h>
ae0a823f	17	#include <unistd.h>
f2b3ef9f JG	18	#include <urcu/rculfhash.h>
	19	#include <urcu/ref.h>
	20	#include <urcu/call-rcu.h>
	21	#include "notification-thread.h"
	22
	23	struct lttng_evaluation;
	24	struct notification_thread_handle;
8abe313a JG	25
	26	struct channel_key {
	27	uint64_t key;
	28	enum lttng_domain_type domain;
	29	};
	30
	31	struct session_info {
	32	struct lttng_ref ref;
	33	char *name;
	34	uid_t uid;
	35	gid_t gid;
	36	/*
c7283958	37	* Hashtable containing back-refs (weak) to all channels in this session.
8abe313a JG	38	* The hashtable's key is a hash of (struct channel_key) and
	39	* the value is of type (struct channel_info *).
	40	*/
	41	struct cds_lfht *channel_infos_ht;
ea9a44f0	42	struct lttng_session_trigger_list *trigger_list;
8abe313a JG	43	/* Node in the notification thread state's sessions_ht. */
8abe313a JG	44	struct cds_lfht_node sessions_ht_node;
1eee26c5 JG	45	/*
	46	* Weak reference to the thread state's sessions_ht. Used for removal on
	47	* destruction.
	48	*/
	49	struct cds_lfht *sessions_ht;
e8360425	50	uint64_t consumed_data_size;
51eab943 JG	51	struct {
	52	/* Whether a rotation is ongoing for this session. */
	53	bool ongoing;
	54	/* Identifier of the currently ongoing rotation. */
	55	uint64_t id;
	56	} rotation;
83b934ad MD	57	/* call_rcu delayed reclaim. */
83b934ad MD	58	struct rcu_head rcu_node;
8abe313a JG	59	};
	60
	61	struct channel_info {
	62	struct channel_key key;
	63	char *name;
	64	uint64_t capacity;
	65	/*
	66	* A channel info holds a reference (lttng_ref) on session_info.
	67	* session_info, in return, holds a weak reference to the channel.
	68	*/
	69	struct session_info *session_info;
	70	/* Node in the notification thread state's channels_ht. */
	71	struct cds_lfht_node channels_ht_node;
	72	/* Node in the session_info's channels_ht. */
	73	struct cds_lfht_node session_info_channels_ht_node;
83b934ad MD	74	/* call_rcu delayed reclaim. */
83b934ad MD	75	struct rcu_head rcu_node;
8abe313a JG	76	};
8abe313a JG	77
b9a8d78f FD	78	/*
	79	* Facilities to carry the different notifications type in the action
	80	* processing code path.
	81	*/
	82	struct lttng_event_notifier_notification {
	83	uint64_t tracer_token;
	84	enum lttng_domain_type type;
82b3cbf4 JR	85	size_t capture_buf_size;
82b3cbf4 JR	86	char *capture_buffer;
b9a8d78f FD	87	};
b9a8d78f FD	88
f2b3ef9f JG	89	struct notification_client_list_element {
	90	struct notification_client *client;
	91	struct cds_list_head node;
	92	};
	93
	94	/*
	95	* Thread safety of notification_client and notification_client_list.
	96	*
	97	* The notification thread (main thread) and the action executor
	98	* interact through client lists. Hence, when the action executor
	99	* thread looks-up the list of clients subscribed to a given
	100	* condition, it will acquire a reference to the list and lock it
	101	* while attempting to communicate with the various clients.
	102	*
	103	* It is not necessary to reference-count clients as they are guaranteed
	104	* to be 'alive' if they are present in a list and that list is locked. Indeed,
	105	* removing references to the client from those subscription lists is part of
	106	* the work performed on destruction of a client.
	107	*
	108	* No provision for other access scenarios are taken into account;
	109	* this is the bare minimum to make these accesses safe and the
	110	* notification thread's state is _not_ "thread-safe" in any general
	111	* sense.
	112	*/
	113	struct notification_client_list {
	114	pthread_mutex_t lock;
	115	struct urcu_ref ref;
091fa780 FD	116	struct lttng_condition *condition;
	117	struct cds_list_head triggers_list;
	118	struct cds_list_head clients_list;
f2b3ef9f JG	119	/* Weak reference to container. */
	120	struct cds_lfht *notification_trigger_clients_ht;
	121	struct cds_lfht_node notification_trigger_clients_ht_node;
	122	/* call_rcu delayed reclaim. */
	123	struct rcu_head rcu_node;
	124	};
	125
	126	struct notification_client {
6c24d3fd JG	127	/*
	128	* Nests within the notification_client_list lock.
	129	*
	130	* Protects the outbound communication and the active flag which
	131	* is used by both the notification and action executor threads.
	132	*
	133	* The remaining fields of the object can be used without any
	134	* synchronization as they are either immutable (id, creds, version) or
	135	* only accessed by the notification thread.
	136	*/
f2b3ef9f JG	137	pthread_mutex_t lock;
	138	notification_client_id id;
	139	int socket;
	140	/* Client protocol version. */
	141	uint8_t major, minor;
	142	uid_t uid;
	143	gid_t gid;
	144	/*
	145	* Indicates if the credentials and versions of the client have been
	146	* checked.
	147	*/
	148	bool validated;
	149	/*
	150	* Conditions to which the client's notification channel is subscribed.
	151	* List of struct lttng_condition_list_node. The condition member is
	152	* owned by the client.
	153	*/
	154	struct cds_list_head condition_list;
	155	struct cds_lfht_node client_socket_ht_node;
	156	struct cds_lfht_node client_id_ht_node;
	157	struct {
	158	/*
	159	* If a client's communication is inactive, it means that a
	160	* fatal error has occurred (could be either a protocol error or
	161	* the socket API returned a fatal error). No further
	162	* communication should be attempted; the client is queued for
	163	* clean-up.
	164	*/
	165	bool active;
	166	struct {
	167	/*
	168	* During the reception of a message, the reception
	169	* buffers' "size" is set to contain the current
	170	* message's complete payload.
	171	*/
882093ee	172	struct lttng_payload payload;
f2b3ef9f JG	173	/* Bytes left to receive for the current message. */
f2b3ef9f JG	174	size_t bytes_to_receive;
882093ee JR	175	/* FDs left to receive for the current message. */
882093ee JR	176	int fds_to_receive;
f2b3ef9f JG	177	/* Type of the message being received. */
	178	enum lttng_notification_channel_message_type msg_type;
	179	/*
	180	* Indicates whether or not credentials are expected
	181	* from the client.
	182	*/
	183	bool expect_creds;
	184	/*
	185	* Indicates whether or not credentials were received
	186	* from the client.
	187	*/
	188	bool creds_received;
	189	/* Only used during credentials reception. */
	190	lttng_sock_cred creds;
	191	} inbound;
	192	struct {
	193	/*
	194	* Indicates whether or not a notification addressed to
	195	* this client was dropped because a command reply was
	196	* already buffered.
	197	*
	198	* A notification is dropped whenever the buffer is not
	199	* empty.
	200	*/
	201	bool dropped_notification;
	202	/*
	203	* Indicates whether or not a command reply is already
	204	* buffered. In this case, it means that the client is
	205	* not consuming command replies before emitting a new
	206	* one. This could be caused by a protocol error or a
	207	* misbehaving/malicious client.
	208	*/
	209	bool queued_command_reply;
882093ee	210	struct lttng_payload payload;
f2b3ef9f JG	211	} outbound;
	212	} communication;
	213	/* call_rcu delayed reclaim. */
	214	struct rcu_head rcu_node;
	215	};
	216
dd877ea6 JG	217	enum client_transmission_status {
	218	CLIENT_TRANSMISSION_STATUS_COMPLETE,
	219	CLIENT_TRANSMISSION_STATUS_QUEUED,
	220	/* Communication failure. */
	221	CLIENT_TRANSMISSION_STATUS_FAIL,
	222	/* Fatal error. */
	223	CLIENT_TRANSMISSION_STATUS_ERROR,
	224	};
f2b3ef9f JG	225
	226	LTTNG_HIDDEN
	227	bool notification_client_list_get(struct notification_client_list *list);
	228
	229	LTTNG_HIDDEN
	230	void notification_client_list_put(struct notification_client_list *list);
	231
6c24d3fd	232	/* Only returns a non-zero value if a fatal error occurred. */
f2b3ef9f JG	233	typedef int (*report_client_transmission_result_cb)(
	234	struct notification_client *client,
	235	enum client_transmission_status status,
	236	void *user_data);
	237
	238	LTTNG_HIDDEN
	239	int notification_client_list_send_evaluation(
	240	struct notification_client_list *list,
	241	const struct lttng_condition *condition,
	242	const struct lttng_evaluation *evaluation,
	243	const struct lttng_credentials *trigger_creds,
	244	const struct lttng_credentials *source_object_creds,
	245	report_client_transmission_result_cb client_report,
	246	void *user_data);
	247
	248	LTTNG_HIDDEN
	249	int notification_thread_client_communication_update(
	250	struct notification_thread_handle *handle,
	251	notification_client_id id,
	252	enum client_transmission_status transmission_status);
	253
82b3cbf4 JR	254	/*
	255	* Takes ownership of the payload if present.
	256	*/
b9a8d78f FD	257	LTTNG_HIDDEN
	258	struct lttng_event_notifier_notification *lttng_event_notifier_notification_create(
	259	uint64_t tracer_token,
82b3cbf4 JR	260	enum lttng_domain_type domain,
	261	char *payload,
	262	size_t payload_size);
b9a8d78f FD	263
	264	LTTNG_HIDDEN
	265	void lttng_event_notifier_notification_destroy(
	266	struct lttng_event_notifier_notification *event_notifier_notification);
	267
8abe313a	268	#endif /* NOTIFICATION_THREAD_INTERNAL_H */