[lttng-tools.git] / src / bin / lttng-sessiond / rotation-thread.c

/*
 * Copyright (C) 2017 - Julien Desfossez <jdesfossez@efficios.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License, version 2 only, as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define _LGPL_SOURCE
#include <lttng/trigger/trigger.h>
#include <common/error.h>
#include <common/config/session-config.h>
#include <common/defaults.h>
#include <common/utils.h>
#include <common/futex.h>
#include <common/align.h>
#include <common/time.h>
#include <common/hashtable/utils.h>
#include <sys/eventfd.h>
#include <sys/stat.h>
#include <time.h>
#include <signal.h>
#include <inttypes.h>

#include <common/kernel-ctl/kernel-ctl.h>
#include <lttng/notification/channel-internal.h>

#include "rotation-thread.h"
#include "lttng-sessiond.h"
#include "health-sessiond.h"
#include "rotate.h"
#include "cmd.h"
#include "session.h"
#include "sessiond-timer.h"

#include <urcu.h>
#include <urcu/list.h>
#include <urcu/rculfhash.h>

/*
 * Store a struct rotation_channel_info for each channel that is currently
 * being rotated by the consumer.
 */
struct cds_lfht *channel_pending_rotate_ht;

struct rotation_thread_state {
	struct lttng_poll_event events;
};

static
void channel_rotation_info_destroy(struct rotation_channel_info *channel_info)
{
	assert(channel_info);
	free(channel_info);
}

static
int match_channel_info(struct cds_lfht_node *node, const void *key)
{
	struct rotation_channel_key *channel_key = (struct rotation_channel_key *) key;
	struct rotation_channel_info *channel_info;

	channel_info = caa_container_of(node, struct rotation_channel_info,
			rotate_channels_ht_node);

	return !!((channel_key->key == channel_info->channel_key.key) &&
			(channel_key->domain == channel_info->channel_key.domain));
}

static
struct rotation_channel_info *lookup_channel_pending(uint64_t key,
		enum lttng_domain_type domain)
{
	struct cds_lfht_iter iter;
	struct cds_lfht_node *node;
	struct rotation_channel_info *channel_info = NULL;
	struct rotation_channel_key channel_key = { .key = key,
			.domain = domain };

	cds_lfht_lookup(channel_pending_rotate_ht,
			hash_channel_key(&channel_key),
			match_channel_info,
			&channel_key, &iter);
	node = cds_lfht_iter_get_node(&iter);
	if (!node) {
		goto end;
	}

	channel_info = caa_container_of(node, struct rotation_channel_info,
			rotate_channels_ht_node);
	cds_lfht_del(channel_pending_rotate_ht, node);
end:
	return channel_info;
}

/*
 * Destroy the thread data previously created by the init function.
 */
void rotation_thread_handle_destroy(
		struct rotation_thread_handle *handle)
{
	int ret;

	if (!handle) {
		goto end;
	}

	if (handle->ust32_consumer >= 0) {
		ret = close(handle->ust32_consumer);
		if (ret) {
			PERROR("close 32-bit consumer channel rotation pipe");
		}
	}
	if (handle->ust64_consumer >= 0) {
		ret = close(handle->ust64_consumer);
		if (ret) {
			PERROR("close 64-bit consumer channel rotation pipe");
		}
	}
	if (handle->kernel_consumer >= 0) {
		ret = close(handle->kernel_consumer);
		if (ret) {
			PERROR("close kernel consumer channel rotation pipe");
		}
	}

end:
	free(handle);
}

struct rotation_thread_handle *rotation_thread_handle_create(
		struct lttng_pipe *ust32_channel_rotate_pipe,
		struct lttng_pipe *ust64_channel_rotate_pipe,
		struct lttng_pipe *kernel_channel_rotate_pipe,
		int thread_quit_pipe,
		struct rotation_thread_timer_queue *rotation_timer_queue)
{
	struct rotation_thread_handle *handle;

	handle = zmalloc(sizeof(*handle));
	if (!handle) {
		goto end;
	}

	if (ust32_channel_rotate_pipe) {
		handle->ust32_consumer =
				lttng_pipe_release_readfd(
					ust32_channel_rotate_pipe);
		if (handle->ust32_consumer < 0) {
			goto error;
		}
	} else {
		handle->ust32_consumer = -1;
	}
	if (ust64_channel_rotate_pipe) {
		handle->ust64_consumer =
				lttng_pipe_release_readfd(
					ust64_channel_rotate_pipe);
		if (handle->ust64_consumer < 0) {
			goto error;
		}
	} else {
		handle->ust64_consumer = -1;
	}
	if (kernel_channel_rotate_pipe) {
		handle->kernel_consumer =
				lttng_pipe_release_readfd(
					kernel_channel_rotate_pipe);
		if (handle->kernel_consumer < 0) {
			goto error;
		}
	} else {
		handle->kernel_consumer = -1;
	}
	handle->thread_quit_pipe = thread_quit_pipe;
	handle->rotation_timer_queue = rotation_timer_queue;

end:
	return handle;
error:
	rotation_thread_handle_destroy(handle);
	return NULL;
}

static
int init_poll_set(struct lttng_poll_event *poll_set,
		struct rotation_thread_handle *handle)
{
	int ret;

	/*
	 * Create pollset with size 5:
	 *	- sessiond quit pipe
	 *	- sessiond timer pipe,
	 *	- consumerd (32-bit user space) channel rotate pipe,
	 *	- consumerd (64-bit user space) channel rotate pipe,
	 *	- consumerd (kernel) channel rotate pipe,
	 */
	ret = lttng_poll_create(poll_set, 5, LTTNG_CLOEXEC);
	if (ret < 0) {
		goto end;
	}

	ret = lttng_poll_add(poll_set, handle->thread_quit_pipe,
			LPOLLIN | LPOLLERR);
	if (ret < 0) {
		ERR("[rotation-thread] Failed to add thread_quit_pipe fd to pollset");
		goto error;
	}
	ret = lttng_poll_add(poll_set,
			lttng_pipe_get_readfd(handle->rotation_timer_queue->event_pipe),
			LPOLLIN | LPOLLERR);
	if (ret < 0) {
		ERR("[rotation-thread] Failed to add rotate_pending fd to pollset");
		goto error;
	}
	ret = lttng_poll_add(poll_set, handle->ust32_consumer,
			LPOLLIN | LPOLLERR);
	if (ret < 0) {
		ERR("[rotation-thread] Failed to add ust-32 channel rotation pipe fd to pollset");
		goto error;
	}
	ret = lttng_poll_add(poll_set, handle->ust64_consumer,
			LPOLLIN | LPOLLERR);
	if (ret < 0) {
		ERR("[rotation-thread] Failed to add ust-64 channel rotation pipe fd to pollset");
		goto error;
	}
	if (handle->kernel_consumer >= 0) {
		ret = lttng_poll_add(poll_set, handle->kernel_consumer,
				LPOLLIN | LPOLLERR);
		if (ret < 0) {
			ERR("[rotation-thread] Failed to add kernel channel rotation pipe fd to pollset");
			goto error;
		}
	}

end:
	return ret;
error:
	lttng_poll_clean(poll_set);
	return ret;
}

static
void fini_thread_state(struct rotation_thread_state *state)
{
	lttng_poll_clean(&state->events);
	cds_lfht_destroy(channel_pending_rotate_ht, NULL);
}

static
int init_thread_state(struct rotation_thread_handle *handle,
		struct rotation_thread_state *state)
{
	int ret;

	memset(state, 0, sizeof(*state));
	lttng_poll_init(&state->events);

	ret = init_poll_set(&state->events, handle);
	if (ret) {
		ERR("[rotation-thread] Failed to initialize rotation thread poll set");
		goto end;
	}

	channel_pending_rotate_ht = cds_lfht_new(DEFAULT_HT_SIZE,
			1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
	if (!channel_pending_rotate_ht) {
		ERR("[rotation-thread] Failed to create channel pending rotation hash table");
		ret = -1;
		goto end;
	}

end:
	return ret;
}

static
int handle_channel_rotation_pipe(int fd, uint32_t revents,
		struct rotation_thread_handle *handle,
		struct rotation_thread_state *state)
{
	int ret = 0;
	enum lttng_domain_type domain;
	struct rotation_channel_info *channel_info;
	struct ltt_session *session = NULL;
	uint64_t key;

	if (fd == handle->ust32_consumer ||
			fd == handle->ust64_consumer) {
		domain = LTTNG_DOMAIN_UST;
	} else if (fd == handle->kernel_consumer) {
		domain = LTTNG_DOMAIN_KERNEL;
	} else {
		ERR("[rotation-thread] Unknown channel rotation pipe fd %d",
				fd);
		abort();
	}

	if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
		ret = lttng_poll_del(&state->events, fd);
		if (ret) {
			ERR("[rotation-thread] Failed to remove consumer "
					"rotation pipe from poll set");
		}
		goto end;
	}

	do {
		ret = read(fd, &key, sizeof(key));
	} while (ret == -1 && errno == EINTR);
	if (ret != sizeof(key)) {
		ERR("[rotation-thread] Failed to read from pipe (fd = %i)",
				fd);
		ret = -1;
		goto end;
	}

	DBG("[rotation-thread] Received notification for chan %" PRIu64
			", domain %d\n", key, domain);

	channel_info = lookup_channel_pending(key, domain);
	if (!channel_info) {
		ERR("[rotation-thread] Failed to find channel_info (key = %"
				PRIu64 ")", key);
		ret = -1;
		goto end;
	}
	rcu_read_lock();
	session_lock_list();
	session = session_find_by_id(channel_info->session_id);
	if (!session) {
		/*
		 * The session may have been destroyed before we had a chance to
		 * perform this action, return gracefully.
		 */
		DBG("[rotation-thread] Session %" PRIu64 " not found",
				channel_info->session_id);
		ret = 0;
		goto end_unlock_session_list;
	}

	session_lock(session);
	if (--session->nr_chan_rotate_pending == 0) {
		time_t now = time(NULL);

		if (now == (time_t) -1) {
			session->rotation_status = LTTNG_ROTATION_STATUS_ERROR;
			ret = LTTNG_ERR_UNK;
			goto end_unlock_session;
		}

		ret = rename_complete_chunk(session, now);
		if (ret < 0) {
			ERR("Failed to rename completed rotation chunk");
			goto end_unlock_session;
		}
		session->rotate_pending = false;
		session->rotation_status = LTTNG_ROTATION_STATUS_COMPLETED;
		session->last_chunk_start_ts = session->current_chunk_start_ts;
		DBG("Rotation completed for session %s", session->name);
	}

	ret = 0;

end_unlock_session:
	channel_rotation_info_destroy(channel_info);
	session_unlock(session);
end_unlock_session_list:
	session_unlock_list();
	rcu_read_unlock();
end:
	return ret;
}

void *thread_rotation(void *data)
{
	int ret;
	struct rotation_thread_handle *handle = data;
	struct rotation_thread_state state;

	DBG("[rotation-thread] Started rotation thread");

	if (!handle) {
		ERR("[rotation-thread] Invalid thread context provided");
		goto end;
	}

	rcu_register_thread();
	rcu_thread_online();

	health_register(health_sessiond, HEALTH_SESSIOND_TYPE_ROTATION);
	health_code_update();

	ret = init_thread_state(handle, &state);
	if (ret) {
		goto end;
	}

	/* Ready to handle client connections. */
	sessiond_notify_ready();

	while (true) {
		int fd_count, i;

		health_poll_entry();
		DBG("[rotation-thread] Entering poll wait");
		ret = lttng_poll_wait(&state.events, -1);
		DBG("[rotation-thread] Poll wait returned (%i)", ret);
		health_poll_exit();
		if (ret < 0) {
			/*
			 * Restart interrupted system call.
			 */
			if (errno == EINTR) {
				continue;
			}
			ERR("[rotation-thread] Error encountered during lttng_poll_wait (%i)", ret);
			goto error;
		}

		fd_count = ret;
		for (i = 0; i < fd_count; i++) {
			int fd = LTTNG_POLL_GETFD(&state.events, i);
			uint32_t revents = LTTNG_POLL_GETEV(&state.events, i);

			DBG("[rotation-thread] Handling fd (%i) activity (%u)",
					fd, revents);

			if (fd == handle->thread_quit_pipe) {
				DBG("[rotation-thread] Quit pipe activity");
				goto exit;
			} else if (fd == handle->ust32_consumer ||
					fd == handle->ust64_consumer ||
					fd == handle->kernel_consumer) {
				ret = handle_channel_rotation_pipe(fd,
						revents, handle, &state);
				if (ret) {
					ERR("[rotation-thread] Handle channel rotation pipe");
					goto error;
				}
			}
		}
	}
exit:
error:
	DBG("[rotation-thread] Exit");
	fini_thread_state(&state);
	health_unregister(health_sessiond);
	rcu_thread_offline();
	rcu_unregister_thread();
end:
	return NULL;
}
Commit	Line	Data
db66e574 JD	1	/*
	2	* Copyright (C) 2017 - Julien Desfossez <jdesfossez@efficios.com>
	3	*
	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms of the GNU General Public License, version 2 only, as
	6	* published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful, but WITHOUT
	9	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	10	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	11	* more details.
	12	*
	13	* You should have received a copy of the GNU General Public License along with
	14	* this program; if not, write to the Free Software Foundation, Inc., 51
	15	* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	16	*/
	17
	18	#define _LGPL_SOURCE
	19	#include <lttng/trigger/trigger.h>
	20	#include <common/error.h>
	21	#include <common/config/session-config.h>
	22	#include <common/defaults.h>
	23	#include <common/utils.h>
	24	#include <common/futex.h>
	25	#include <common/align.h>
	26	#include <common/time.h>
	27	#include <common/hashtable/utils.h>
	28	#include <sys/eventfd.h>
	29	#include <sys/stat.h>
	30	#include <time.h>
	31	#include <signal.h>
	32	#include <inttypes.h>
	33
	34	#include <common/kernel-ctl/kernel-ctl.h>
	35	#include <lttng/notification/channel-internal.h>
	36
	37	#include "rotation-thread.h"
	38	#include "lttng-sessiond.h"
	39	#include "health-sessiond.h"
	40	#include "rotate.h"
	41	#include "cmd.h"
	42	#include "session.h"
d086f507	43	#include "sessiond-timer.h"
db66e574 JD	44
	45	#include <urcu.h>
	46	#include <urcu/list.h>
	47	#include <urcu/rculfhash.h>
	48
	49	/*
	50	* Store a struct rotation_channel_info for each channel that is currently
	51	* being rotated by the consumer.
	52	*/
	53	struct cds_lfht *channel_pending_rotate_ht;
	54
	55	struct rotation_thread_state {
	56	struct lttng_poll_event events;
	57	};
	58
	59	static
	60	void channel_rotation_info_destroy(struct rotation_channel_info *channel_info)
	61	{
	62	assert(channel_info);
	63	free(channel_info);
	64	}
	65
	66	static
	67	int match_channel_info(struct cds_lfht_node node, const void key)
	68	{
	69	struct rotation_channel_key channel_key = (struct rotation_channel_key ) key;
	70	struct rotation_channel_info *channel_info;
	71
	72	channel_info = caa_container_of(node, struct rotation_channel_info,
	73	rotate_channels_ht_node);
	74
	75	return !!((channel_key->key == channel_info->channel_key.key) &&
	76	(channel_key->domain == channel_info->channel_key.domain));
	77	}
	78
	79	static
	80	struct rotation_channel_info *lookup_channel_pending(uint64_t key,
	81	enum lttng_domain_type domain)
	82	{
	83	struct cds_lfht_iter iter;
	84	struct cds_lfht_node *node;
	85	struct rotation_channel_info *channel_info = NULL;
	86	struct rotation_channel_key channel_key = { .key = key,
	87	.domain = domain };
	88
	89	cds_lfht_lookup(channel_pending_rotate_ht,
	90	hash_channel_key(&channel_key),
	91	match_channel_info,
	92	&channel_key, &iter);
	93	node = cds_lfht_iter_get_node(&iter);
	94	if (!node) {
	95	goto end;
	96	}
	97
	98	channel_info = caa_container_of(node, struct rotation_channel_info,
	99	rotate_channels_ht_node);
	100	cds_lfht_del(channel_pending_rotate_ht, node);
	101	end:
	102	return channel_info;
	103	}
	104
	105	/*
	106	* Destroy the thread data previously created by the init function.
	107	*/
108	void rotation_thread_handle_destroy(
109	struct rotation_thread_handle *handle)
110	{
111	int ret;
112
113	if (!handle) {
114	goto end;
115	}
116
117	if (handle->ust32_consumer >= 0) {
118	ret = close(handle->ust32_consumer);
119	if (ret) {
120	PERROR("close 32-bit consumer channel rotation pipe");
121	}
122	}
123	if (handle->ust64_consumer >= 0) {
124	ret = close(handle->ust64_consumer);
125	if (ret) {
126	PERROR("close 64-bit consumer channel rotation pipe");
127	}
128	}
129	if (handle->kernel_consumer >= 0) {
130	ret = close(handle->kernel_consumer);
131	if (ret) {
132	PERROR("close kernel consumer channel rotation pipe");
133	}
134	}
135
136	end:
137	free(handle);
138	}
139
140	struct rotation_thread_handle *rotation_thread_handle_create(
141	struct lttng_pipe *ust32_channel_rotate_pipe,
142	struct lttng_pipe *ust64_channel_rotate_pipe,
143	struct lttng_pipe *kernel_channel_rotate_pipe,
d086f507 JD	144	int thread_quit_pipe,
d086f507 JD	145	struct rotation_thread_timer_queue *rotation_timer_queue)
db66e574 JD	146	{
	147	struct rotation_thread_handle *handle;
	148
	149	handle = zmalloc(sizeof(*handle));
	150	if (!handle) {
	151	goto end;
	152	}
	153
	154	if (ust32_channel_rotate_pipe) {
	155	handle->ust32_consumer =
	156	lttng_pipe_release_readfd(
	157	ust32_channel_rotate_pipe);
	158	if (handle->ust32_consumer < 0) {
	159	goto error;
	160	}
	161	} else {
	162	handle->ust32_consumer = -1;
	163	}
	164	if (ust64_channel_rotate_pipe) {
	165	handle->ust64_consumer =
	166	lttng_pipe_release_readfd(
	167	ust64_channel_rotate_pipe);
	168	if (handle->ust64_consumer < 0) {
	169	goto error;
	170	}
	171	} else {
	172	handle->ust64_consumer = -1;
	173	}
	174	if (kernel_channel_rotate_pipe) {
	175	handle->kernel_consumer =
	176	lttng_pipe_release_readfd(
	177	kernel_channel_rotate_pipe);
	178	if (handle->kernel_consumer < 0) {
	179	goto error;
	180	}
	181	} else {
	182	handle->kernel_consumer = -1;
	183	}
	184	handle->thread_quit_pipe = thread_quit_pipe;
d086f507	185	handle->rotation_timer_queue = rotation_timer_queue;
db66e574 JD	186
	187	end:
	188	return handle;
	189	error:
	190	rotation_thread_handle_destroy(handle);
	191	return NULL;
	192	}
	193
	194	static
	195	int init_poll_set(struct lttng_poll_event *poll_set,
	196	struct rotation_thread_handle *handle)
	197	{
	198	int ret;
	199
	200	/*
d086f507	201	* Create pollset with size 5:
db66e574	202	* - sessiond quit pipe
d086f507	203	* - sessiond timer pipe,
db66e574 JD	204	* - consumerd (32-bit user space) channel rotate pipe,
	205	* - consumerd (64-bit user space) channel rotate pipe,
	206	* - consumerd (kernel) channel rotate pipe,
	207	*/
d086f507	208	ret = lttng_poll_create(poll_set, 5, LTTNG_CLOEXEC);
db66e574 JD	209	if (ret < 0) {
	210	goto end;
	211	}
	212
	213	ret = lttng_poll_add(poll_set, handle->thread_quit_pipe,
	214	LPOLLIN \| LPOLLERR);
	215	if (ret < 0) {
	216	ERR("[rotation-thread] Failed to add thread_quit_pipe fd to pollset");
	217	goto error;
	218	}
d086f507 JD	219	ret = lttng_poll_add(poll_set,
	220	lttng_pipe_get_readfd(handle->rotation_timer_queue->event_pipe),
	221	LPOLLIN \| LPOLLERR);
	222	if (ret < 0) {
	223	ERR("[rotation-thread] Failed to add rotate_pending fd to pollset");
	224	goto error;
	225	}
db66e574 JD	226	ret = lttng_poll_add(poll_set, handle->ust32_consumer,
	227	LPOLLIN \| LPOLLERR);
	228	if (ret < 0) {
	229	ERR("[rotation-thread] Failed to add ust-32 channel rotation pipe fd to pollset");
	230	goto error;
	231	}
	232	ret = lttng_poll_add(poll_set, handle->ust64_consumer,
	233	LPOLLIN \| LPOLLERR);
	234	if (ret < 0) {
	235	ERR("[rotation-thread] Failed to add ust-64 channel rotation pipe fd to pollset");
	236	goto error;
	237	}
	238	if (handle->kernel_consumer >= 0) {
	239	ret = lttng_poll_add(poll_set, handle->kernel_consumer,
	240	LPOLLIN \| LPOLLERR);
	241	if (ret < 0) {
	242	ERR("[rotation-thread] Failed to add kernel channel rotation pipe fd to pollset");
	243	goto error;
	244	}
	245	}
	246
	247	end:
	248	return ret;
	249	error:
	250	lttng_poll_clean(poll_set);
	251	return ret;
	252	}
	253
	254	static
	255	void fini_thread_state(struct rotation_thread_state *state)
	256	{
	257	lttng_poll_clean(&state->events);
	258	cds_lfht_destroy(channel_pending_rotate_ht, NULL);
	259	}
	260
	261	static
	262	int init_thread_state(struct rotation_thread_handle *handle,
	263	struct rotation_thread_state *state)
	264	{
	265	int ret;
	266
	267	memset(state, 0, sizeof(*state));
	268	lttng_poll_init(&state->events);
	269
	270	ret = init_poll_set(&state->events, handle);
	271	if (ret) {
	272	ERR("[rotation-thread] Failed to initialize rotation thread poll set");
	273	goto end;
	274	}
	275
	276	channel_pending_rotate_ht = cds_lfht_new(DEFAULT_HT_SIZE,
	277	1, 0, CDS_LFHT_AUTO_RESIZE \| CDS_LFHT_ACCOUNTING, NULL);
	278	if (!channel_pending_rotate_ht) {
	279	ERR("[rotation-thread] Failed to create channel pending rotation hash table");
	280	ret = -1;
	281	goto end;
	282	}
	283
	284	end:
	285	return ret;
	286	}
	287
	288	static
	289	int handle_channel_rotation_pipe(int fd, uint32_t revents,
290	struct rotation_thread_handle *handle,
291	struct rotation_thread_state *state)
292	{
293	int ret = 0;
294	enum lttng_domain_type domain;
295	struct rotation_channel_info *channel_info;
296	struct ltt_session *session = NULL;
297	uint64_t key;
298
299	if (fd == handle->ust32_consumer \|\|
300	fd == handle->ust64_consumer) {
301	domain = LTTNG_DOMAIN_UST;
302	} else if (fd == handle->kernel_consumer) {
303	domain = LTTNG_DOMAIN_KERNEL;
304	} else {
305	ERR("[rotation-thread] Unknown channel rotation pipe fd %d",
306	fd);
307	abort();
308	}
309
310	if (revents & (LPOLLERR \| LPOLLHUP \| LPOLLRDHUP)) {
311	ret = lttng_poll_del(&state->events, fd);
312	if (ret) {
313	ERR("[rotation-thread] Failed to remove consumer "
314	"rotation pipe from poll set");
315	}
316	goto end;
317	}
318
319	do {
320	ret = read(fd, &key, sizeof(key));
321	} while (ret == -1 && errno == EINTR);
322	if (ret != sizeof(key)) {
323	ERR("[rotation-thread] Failed to read from pipe (fd = %i)",
324	fd);
325	ret = -1;
326	goto end;
327	}
328
329	DBG("[rotation-thread] Received notification for chan %" PRIu64
330	", domain %d\n", key, domain);
331
332	channel_info = lookup_channel_pending(key, domain);
333	if (!channel_info) {
334	ERR("[rotation-thread] Failed to find channel_info (key = %"
335	PRIu64 ")", key);
336	ret = -1;
337	goto end;
338	}
339	rcu_read_lock();
340	session_lock_list();
341	session = session_find_by_id(channel_info->session_id);
342	if (!session) {
343	/*
344	* The session may have been destroyed before we had a chance to
345	* perform this action, return gracefully.
346	*/
347	DBG("[rotation-thread] Session %" PRIu64 " not found",
348	channel_info->session_id);
349	ret = 0;
350	goto end_unlock_session_list;
351	}
352
353	session_lock(session);
354	if (--session->nr_chan_rotate_pending == 0) {
355	time_t now = time(NULL);
356
357	if (now == (time_t) -1) {
358	session->rotation_status = LTTNG_ROTATION_STATUS_ERROR;
359	ret = LTTNG_ERR_UNK;
360	goto end_unlock_session;
361	}
362
363	ret = rename_complete_chunk(session, now);
364	if (ret < 0) {
365	ERR("Failed to rename completed rotation chunk");
366	goto end_unlock_session;
367	}
368	session->rotate_pending = false;
369	session->rotation_status = LTTNG_ROTATION_STATUS_COMPLETED;
370	session->last_chunk_start_ts = session->current_chunk_start_ts;
371	DBG("Rotation completed for session %s", session->name);
372	}
373
374	ret = 0;
375
376	end_unlock_session:
377	channel_rotation_info_destroy(channel_info);
378	session_unlock(session);
379	end_unlock_session_list:
380	session_unlock_list();
381	rcu_read_unlock();
382	end:
383	return ret;
384	}
385
386	void thread_rotation(void data)
387	{
388	int ret;
389	struct rotation_thread_handle *handle = data;
390	struct rotation_thread_state state;
391
392	DBG("[rotation-thread] Started rotation thread");
393
394	if (!handle) {
395	ERR("[rotation-thread] Invalid thread context provided");
396	goto end;
397	}
398
399	rcu_register_thread();
400	rcu_thread_online();
401
402	health_register(health_sessiond, HEALTH_SESSIOND_TYPE_ROTATION);
403	health_code_update();
404
405	ret = init_thread_state(handle, &state);
406	if (ret) {
407	goto end;
408	}
409
410	/* Ready to handle client connections. */
411	sessiond_notify_ready();
412
413	while (true) {
414	int fd_count, i;
415
416	health_poll_entry();
417	DBG("[rotation-thread] Entering poll wait");
418	ret = lttng_poll_wait(&state.events, -1);
419	DBG("[rotation-thread] Poll wait returned (%i)", ret);
420	health_poll_exit();
421	if (ret < 0) {
422	/*
423	* Restart interrupted system call.
424	*/
425	if (errno == EINTR) {
426	continue;
427	}
428	ERR("[rotation-thread] Error encountered during lttng_poll_wait (%i)", ret);
429	goto error;
430	}
431
432	fd_count = ret;
433	for (i = 0; i < fd_count; i++) {
434	int fd = LTTNG_POLL_GETFD(&state.events, i);
435	uint32_t revents = LTTNG_POLL_GETEV(&state.events, i);
436
437	DBG("[rotation-thread] Handling fd (%i) activity (%u)",
438	fd, revents);
439
440	if (fd == handle->thread_quit_pipe) {
441	DBG("[rotation-thread] Quit pipe activity");
442	goto exit;
443	} else if (fd == handle->ust32_consumer \|\|
444	fd == handle->ust64_consumer \|\|
445	fd == handle->kernel_consumer) {
446	ret = handle_channel_rotation_pipe(fd,
447	revents, handle, &state);
448	if (ret) {
449	ERR("[rotation-thread] Handle channel rotation pipe");
450	goto error;
451	}
452	}
453	}
454	}
455	exit:
456	error:
457	DBG("[rotation-thread] Exit");
458	fini_thread_state(&state);
459	health_unregister(health_sessiond);
460	rcu_thread_offline();
461	rcu_unregister_thread();
462	end:
463	return NULL;
464	}