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

/*
 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
 * Copyright (C) 2013 Raphaël Beamonte <raphael.beamonte@gmail.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#ifndef _LTT_SESSIOND_H
#define _LTT_SESSIOND_H

#include <urcu.h>
#include <urcu/wfcqueue.h>

#include <common/sessiond-comm/sessiond-comm.h>
#include <common/payload.h>
#include <common/compat/poll.h>
#include <common/compat/socket.h>
#include <common/uuid.h>

#include "session.h"
#include "ust-app.h"
#include "notification-thread.h"
#include "sessiond-config.h"

/*
 * Consumer daemon state which is changed when spawning it, killing it or in
 * case of a fatal error.
 */
enum consumerd_state {
	CONSUMER_STARTED = 1,
	CONSUMER_STOPPED = 2,
	CONSUMER_ERROR   = 3,
};

/* Unique identifier of a session daemon instance. */
extern lttng_uuid the_sessiond_uuid;

/*
 * This consumer daemon state is used to validate if a client command will be
 * able to reach the consumer. If not, the client is informed. For instance,
 * doing a "lttng start" when the consumer state is set to ERROR will return an
 * error to the client.
 *
 * The following example shows a possible race condition of this scheme:
 *
 * consumer thread error happens
 *                                    client cmd arrives
 *                                    client cmd checks state -> still OK
 * consumer thread exit, sets error
 *                                    client cmd try to talk to consumer
 *                                    ...
 *
 * However, since the consumer is a different daemon, we have no way of making
 * sure the command will reach it safely even with this state flag. This is why
 * we consider that up to the state validation during command processing, the
 * command is safe. After that, we can not guarantee the correctness of the
 * client request vis-a-vis the consumer.
 */
extern enum consumerd_state the_ust_consumerd_state;
extern enum consumerd_state the_kernel_consumerd_state;

/* Set in main.c at boot time of the daemon */
extern struct lttng_kernel_abi_tracer_version the_kernel_tracer_version;
extern struct lttng_kernel_abi_tracer_abi_version the_kernel_tracer_abi_version;

/* Notification thread handle. */
extern struct notification_thread_handle *the_notification_thread_handle;

/*
 * This contains extra data needed for processing a command received by the
 * session daemon from the lttng client.
 */
struct command_ctx {
	unsigned int lttng_msg_size;
	struct ltt_session *session;
	/* Input message */
	struct lttcomm_session_msg lsm;
	/* Reply content, starts with an lttcomm_lttng_msg header. */
	struct lttng_payload reply_payload;
	lttng_sock_cred creds;
};

struct ust_command {
	int sock;
	struct ust_register_msg reg_msg;
	struct cds_wfcq_node node;
};

/*
 * Queue used to enqueue UST registration request (ust_command) and synchronized
 * by a futex with a scheme N wakers / 1 waiters. See futex.c/.h
 */
struct ust_cmd_queue {
	int32_t futex;
	struct cds_wfcq_head head;
	struct cds_wfcq_tail tail;
};

/*
 * This is the wait queue containing wait nodes during the application
 * registration process.
 */
struct ust_reg_wait_queue {
	unsigned long count;
	struct cds_list_head head;
};

/*
 * Use by the dispatch registration to queue UST command socket to wait for the
 * notify socket.
 */
struct ust_reg_wait_node {
	struct ust_app *app;
	struct cds_list_head head;
};

/*
 * Used to notify that a hash table needs to be destroyed by dedicated
 * thread. Required by design because we don't want to move destroy
 * paths outside of large RCU read-side lock paths, and destroy cannot
 * be called by call_rcu thread, because it may hang (waiting for
 * call_rcu completion).
 */
extern int the_ht_cleanup_pipe[2];

extern int the_kernel_poll_pipe[2];

/*
 * Populated when the daemon starts with the current page size of the system.
 * Set in main() with the current page size.
 */
extern long the_page_size;

/* Application health monitoring */
extern struct health_app *the_health_sessiond;

extern struct sessiond_config the_config;

extern int the_ust_consumerd64_fd, the_ust_consumerd32_fd;

/* Parent PID for --sig-parent option */
extern pid_t the_ppid;
/* Internal parent PID use with daemonize. */
extern pid_t the_child_ppid;

/* Consumer daemon specific control data. */
extern struct consumer_data the_ustconsumer32_data;
extern struct consumer_data the_ustconsumer64_data;
extern struct consumer_data the_kconsumer_data;

int sessiond_init_thread_quit_pipe(void);
int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
int sessiond_wait_for_quit_pipe(int timeout_ms);
int sessiond_notify_quit_pipe(void);
void sessiond_close_quit_pipe(void);

int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
void sessiond_signal_parents(void);

void sessiond_set_client_thread_state(bool running);
void sessiond_wait_client_thread_stopped(void);

void *thread_manage_consumer(void *data);

#endif /* _LTT_SESSIOND_H */
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
	3	* Copyright (C) 2013 Raphaël Beamonte <raphael.beamonte@gmail.com>
	4	*
	5	* SPDX-License-Identifier: GPL-2.0-only
	6	*
	7	*/
	8
	9	#ifndef _LTT_SESSIOND_H
	10	#define _LTT_SESSIOND_H
	11
	12	#include <urcu.h>
	13	#include <urcu/wfcqueue.h>
	14
	15	#include <common/sessiond-comm/sessiond-comm.h>
	16	#include <common/payload.h>
	17	#include <common/compat/poll.h>
	18	#include <common/compat/socket.h>
	19	#include <common/uuid.h>
	20
	21	#include "session.h"
	22	#include "ust-app.h"
	23	#include "notification-thread.h"
	24	#include "sessiond-config.h"
	25
	26	/*
	27	* Consumer daemon state which is changed when spawning it, killing it or in
	28	* case of a fatal error.
	29	*/
	30	enum consumerd_state {
	31	CONSUMER_STARTED = 1,
	32	CONSUMER_STOPPED = 2,
	33	CONSUMER_ERROR = 3,
	34	};
	35
	36	/* Unique identifier of a session daemon instance. */
	37	extern lttng_uuid the_sessiond_uuid;
	38
	39	/*
	40	* This consumer daemon state is used to validate if a client command will be
	41	* able to reach the consumer. If not, the client is informed. For instance,
	42	* doing a "lttng start" when the consumer state is set to ERROR will return an
	43	* error to the client.
	44	*
	45	* The following example shows a possible race condition of this scheme:
	46	*
	47	* consumer thread error happens
	48	* client cmd arrives
	49	* client cmd checks state -> still OK
	50	* consumer thread exit, sets error
	51	* client cmd try to talk to consumer
	52	* ...
	53	*
	54	* However, since the consumer is a different daemon, we have no way of making
	55	* sure the command will reach it safely even with this state flag. This is why
	56	* we consider that up to the state validation during command processing, the
	57	* command is safe. After that, we can not guarantee the correctness of the
	58	* client request vis-a-vis the consumer.
	59	*/
	60	extern enum consumerd_state the_ust_consumerd_state;
	61	extern enum consumerd_state the_kernel_consumerd_state;
	62
	63	/* Set in main.c at boot time of the daemon */
	64	extern struct lttng_kernel_abi_tracer_version the_kernel_tracer_version;
	65	extern struct lttng_kernel_abi_tracer_abi_version the_kernel_tracer_abi_version;
	66
	67	/* Notification thread handle. */
	68	extern struct notification_thread_handle *the_notification_thread_handle;
	69
	70	/*
	71	* This contains extra data needed for processing a command received by the
	72	* session daemon from the lttng client.
	73	*/
	74	struct command_ctx {
	75	unsigned int lttng_msg_size;
	76	struct ltt_session *session;
	77	/* Input message */
	78	struct lttcomm_session_msg lsm;
	79	/* Reply content, starts with an lttcomm_lttng_msg header. */
	80	struct lttng_payload reply_payload;
	81	lttng_sock_cred creds;
	82	};
	83
	84	struct ust_command {
	85	int sock;
	86	struct ust_register_msg reg_msg;
	87	struct cds_wfcq_node node;
	88	};
	89
	90	/*
	91	* Queue used to enqueue UST registration request (ust_command) and synchronized
	92	* by a futex with a scheme N wakers / 1 waiters. See futex.c/.h
	93	*/
	94	struct ust_cmd_queue {
	95	int32_t futex;
	96	struct cds_wfcq_head head;
	97	struct cds_wfcq_tail tail;
	98	};
	99
	100	/*
	101	* This is the wait queue containing wait nodes during the application
	102	* registration process.
	103	*/
	104	struct ust_reg_wait_queue {
	105	unsigned long count;
	106	struct cds_list_head head;
	107	};
	108
	109	/*
	110	* Use by the dispatch registration to queue UST command socket to wait for the
	111	* notify socket.
	112	*/
	113	struct ust_reg_wait_node {
	114	struct ust_app *app;
	115	struct cds_list_head head;
	116	};
	117
	118	/*
	119	* Used to notify that a hash table needs to be destroyed by dedicated
	120	* thread. Required by design because we don't want to move destroy
	121	* paths outside of large RCU read-side lock paths, and destroy cannot
	122	* be called by call_rcu thread, because it may hang (waiting for
	123	* call_rcu completion).
	124	*/
	125	extern int the_ht_cleanup_pipe[2];
	126
	127	extern int the_kernel_poll_pipe[2];
	128
	129	/*
	130	* Populated when the daemon starts with the current page size of the system.
	131	* Set in main() with the current page size.
	132	*/
	133	extern long the_page_size;
	134
	135	/* Application health monitoring */
	136	extern struct health_app *the_health_sessiond;
	137
	138	extern struct sessiond_config the_config;
	139
	140	extern int the_ust_consumerd64_fd, the_ust_consumerd32_fd;
	141
	142	/* Parent PID for --sig-parent option */
	143	extern pid_t the_ppid;
	144	/* Internal parent PID use with daemonize. */
	145	extern pid_t the_child_ppid;
	146
	147	/* Consumer daemon specific control data. */
	148	extern struct consumer_data the_ustconsumer32_data;
	149	extern struct consumer_data the_ustconsumer64_data;
	150	extern struct consumer_data the_kconsumer_data;
	151
	152	int sessiond_init_thread_quit_pipe(void);
	153	int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
	154	int sessiond_wait_for_quit_pipe(int timeout_ms);
	155	int sessiond_notify_quit_pipe(void);
	156	void sessiond_close_quit_pipe(void);
	157
	158	int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
	159	void sessiond_signal_parents(void);
	160
	161	void sessiond_set_client_thread_state(bool running);
	162	void sessiond_wait_client_thread_stopped(void);
	163
	164	void thread_manage_consumer(void data);
	165
	166	#endif /* _LTT_SESSIOND_H */