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

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 * Copyright (C) 2016 - Jérémie Galarneau <jeremie.galarneau@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 <inttypes.h>
#include <string.h>
#include <unistd.h>

#include <common/common.h>
#include <common/defaults.h>
#include <common/sessiond-comm/sessiond-comm.h>

#include "channel.h"
#include "lttng-sessiond.h"
#include "kernel.h"
#include "ust-ctl.h"
#include "utils.h"
#include "ust-app.h"
#include "agent.h"

/*
 * Return allocated channel attributes.
 */
struct lttng_channel *channel_new_default_attr(int dom,
		enum lttng_buffer_type type)
{
	struct lttng_channel *chan;
	const char *channel_name = DEFAULT_CHANNEL_NAME;
	struct lttng_channel_extended *extended_attr = NULL;

	chan = zmalloc(sizeof(struct lttng_channel));
	if (chan == NULL) {
		PERROR("zmalloc channel init");
		goto error_alloc;
	}

	extended_attr = zmalloc(sizeof(struct lttng_channel_extended));
	if (!extended_attr) {
		PERROR("zmalloc channel extended init");
		goto error;
	}

	chan->attr.extended.ptr = extended_attr;

	/* Same for all domains. */
	chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
	chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
	chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;

	switch (dom) {
	case LTTNG_DOMAIN_KERNEL:
		assert(type == LTTNG_BUFFER_GLOBAL);
		chan->attr.subbuf_size =
			default_get_kernel_channel_subbuf_size();
		chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
		chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
		chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
		chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
		chan->attr.live_timer_interval = DEFAULT_KERNEL_CHANNEL_LIVE_TIMER;
		extended_attr->blocking_timeout = DEFAULT_KERNEL_CHANNEL_BLOCKING_TIMEOUT;
		extended_attr->monitor_timer_interval =
			DEFAULT_KERNEL_CHANNEL_MONITOR_TIMER;
		break;
	case LTTNG_DOMAIN_JUL:
		channel_name = DEFAULT_JUL_CHANNEL_NAME;
		goto common_ust;
	case LTTNG_DOMAIN_LOG4J:
		channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
		goto common_ust;
	case LTTNG_DOMAIN_PYTHON:
		channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
		goto common_ust;
	case LTTNG_DOMAIN_UST:
common_ust:
		switch (type) {
		case LTTNG_BUFFER_PER_UID:
			chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
			chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
			chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
			chan->attr.switch_timer_interval =
				DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
			chan->attr.read_timer_interval =
				DEFAULT_UST_UID_CHANNEL_READ_TIMER;
			chan->attr.live_timer_interval =
				DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
			extended_attr->blocking_timeout = DEFAULT_UST_UID_CHANNEL_BLOCKING_TIMEOUT;
			extended_attr->monitor_timer_interval =
				DEFAULT_UST_UID_CHANNEL_MONITOR_TIMER;
			break;
		case LTTNG_BUFFER_PER_PID:
		default:
			chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
			chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
			chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
			chan->attr.switch_timer_interval =
				DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
			chan->attr.read_timer_interval =
				DEFAULT_UST_PID_CHANNEL_READ_TIMER;
			chan->attr.live_timer_interval =
				DEFAULT_UST_PID_CHANNEL_LIVE_TIMER;
			extended_attr->blocking_timeout = DEFAULT_UST_PID_CHANNEL_BLOCKING_TIMEOUT;
			extended_attr->monitor_timer_interval =
				DEFAULT_UST_PID_CHANNEL_MONITOR_TIMER;
			break;
		}
		break;
	default:
		goto error;	/* Not implemented */
	}

	if (snprintf(chan->name, sizeof(chan->name), "%s",
			channel_name) < 0) {
		PERROR("snprintf default channel name");
		goto error;
	}
	return chan;

error:
	free(extended_attr);
	free(chan);
error_alloc:
	return NULL;
}

void channel_attr_destroy(struct lttng_channel *channel)
{
	if (!channel) {
		return;
	}
	free(channel->attr.extended.ptr);
	free(channel);
}

/*
 * Disable kernel channel of the kernel session.
 */
int channel_kernel_disable(struct ltt_kernel_session *ksession,
		char *channel_name)
{
	int ret;
	struct ltt_kernel_channel *kchan;

	assert(ksession);
	assert(channel_name);

	kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
	if (kchan == NULL) {
		ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
		goto error;
	}

	/* Only if channel is enabled disable it. */
	if (kchan->enabled == 1) {
		ret = kernel_disable_channel(kchan);
		if (ret < 0 && ret != -EEXIST) {
			ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
			goto error;
		}
	}

	ret = LTTNG_OK;

error:
	return ret;
}

/*
 * Enable kernel channel of the kernel session.
 */
int channel_kernel_enable(struct ltt_kernel_session *ksession,
		struct ltt_kernel_channel *kchan)
{
	int ret;

	assert(ksession);
	assert(kchan);

	if (kchan->enabled == 0) {
		ret = kernel_enable_channel(kchan);
		if (ret < 0) {
			ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
			goto error;
		}
	} else {
		ret = LTTNG_ERR_KERN_CHAN_EXIST;
		goto error;
	}

	ret = LTTNG_OK;

error:
	return ret;
}

static int channel_validate(struct lttng_channel *attr)
{
	/*
	 * The ringbuffer (both in user space and kernel) behaves badly
	 * in overwrite mode and with less than 2 subbuffers so block it
	 * right away and send back an invalid attribute error.
	 */
	if (attr->attr.overwrite && attr->attr.num_subbuf < 2) {
		return -1;
	}
	return 0;
}

static int channel_validate_kernel(struct lttng_channel *attr)
{
	/* Kernel channels do not support blocking timeout. */
	if (((struct lttng_channel_extended *)attr->attr.extended.ptr)->blocking_timeout) {
		return -1;
	}
	return 0;
}

/*
 * Create kernel channel of the kernel session and notify kernel thread.
 */
int channel_kernel_create(struct ltt_kernel_session *ksession,
		struct lttng_channel *attr, int kernel_pipe)
{
	int ret;
	struct lttng_channel *defattr = NULL;

	assert(ksession);

	/* Creating channel attributes if needed */
	if (attr == NULL) {
		defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
				LTTNG_BUFFER_GLOBAL);
		if (defattr == NULL) {
			ret = LTTNG_ERR_FATAL;
			goto error;
		}
		attr = defattr;
	}

	/*
	 * Set the overwrite mode for this channel based on the session
	 * type unless the client explicitly overrides the channel mode.
	 */
	if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
		attr->attr.overwrite = !!ksession->snapshot_mode;
	}

	/* Enforce mmap output for snapshot sessions. */
	if (ksession->snapshot_mode) {
		attr->attr.output = LTTNG_EVENT_MMAP;
	}

	/* Validate common channel properties. */
	if (channel_validate(attr) < 0) {
		ret = LTTNG_ERR_INVALID;
		goto error;
	}

	if (channel_validate_kernel(attr) < 0) {
		ret = LTTNG_ERR_INVALID;
		goto error;
	}

	/* Channel not found, creating it */
	ret = kernel_create_channel(ksession, attr);
	if (ret < 0) {
		ret = LTTNG_ERR_KERN_CHAN_FAIL;
		goto error;
	}

	/* Notify kernel thread that there is a new channel */
	ret = notify_thread_pipe(kernel_pipe);
	if (ret < 0) {
		ret = LTTNG_ERR_FATAL;
		goto error;
	}

	ret = LTTNG_OK;
error:
	channel_attr_destroy(defattr);
	return ret;
}

/*
 * Enable UST channel for session and domain.
 */
int channel_ust_enable(struct ltt_ust_session *usess,
		struct ltt_ust_channel *uchan)
{
	int ret = LTTNG_OK;

	assert(usess);
	assert(uchan);

	/* If already enabled, everything is OK */
	if (uchan->enabled) {
		DBG3("Channel %s already enabled. Skipping", uchan->name);
		ret = LTTNG_ERR_UST_CHAN_EXIST;
		goto end;
	}

	DBG2("Channel %s being enabled in UST domain", uchan->name);

	/*
	 * Enable channel for UST global domain on all applications. Ignore return
	 * value here since whatever error we got, it means that the channel was
	 * not created on one or many registered applications and we can not report
	 * this to the user yet. However, at this stage, the channel was
	 * successfully created on the session daemon side so the enable-channel
	 * command is a success.
	 */
	(void) ust_app_enable_channel_glb(usess, uchan);

	uchan->enabled = 1;
	DBG2("Channel %s enabled successfully", uchan->name);

end:
	return ret;
}

/*
 * Create UST channel for session and domain.
 */
int channel_ust_create(struct ltt_ust_session *usess,
		struct lttng_channel *attr, enum lttng_buffer_type type)
{
	int ret = LTTNG_OK;
	struct ltt_ust_channel *uchan = NULL;
	struct lttng_channel *defattr = NULL;
	enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
	bool chan_published = false;

	assert(usess);

	/* Creating channel attributes if needed */
	if (attr == NULL) {
		defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
		if (defattr == NULL) {
			ret = LTTNG_ERR_FATAL;
			goto error;
		}
		attr = defattr;
	} else {
		/*
		 * HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
		 * based on the default name.
		 */
		if (!strcmp(attr->name, DEFAULT_JUL_CHANNEL_NAME)) {
			domain = LTTNG_DOMAIN_JUL;
		} else if (!strcmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
			domain = LTTNG_DOMAIN_LOG4J;
		} else if (!strcmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
			domain = LTTNG_DOMAIN_PYTHON;
		}
	}

	/*
	 * Set the overwrite mode for this channel based on the session
	 * type unless the client explicitly overrides the channel mode.
	 */
	if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
		attr->attr.overwrite = !!usess->snapshot_mode;
	}

	/* Enforce mmap output for snapshot sessions. */
	if (usess->snapshot_mode) {
		attr->attr.output = LTTNG_EVENT_MMAP;
	}

	/* Validate common channel properties. */
	if (channel_validate(attr) < 0) {
		ret = LTTNG_ERR_INVALID;
		goto error;
	}

	/*
	 * Validate UST buffer size and number of buffers: must both be power of 2
	 * and nonzero. We validate right here for UST, because applications will
	 * not report the error to the user (unlike kernel tracing).
	 */
	if (!attr->attr.subbuf_size ||
			(attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
		ret = LTTNG_ERR_INVALID;
		goto error;
	}

	/*
	 * Invalid subbuffer size if it's lower then the page size.
	 */
	if (attr->attr.subbuf_size < page_size) {
		ret = LTTNG_ERR_INVALID;
		goto error;
	}

	if (!attr->attr.num_subbuf ||
			(attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
		ret = LTTNG_ERR_INVALID;
		goto error;
	}

	if (attr->attr.output != LTTNG_EVENT_MMAP) {
		ret = LTTNG_ERR_NOT_SUPPORTED;
		goto error;
	}

	/*
	 * The tracefile_size should not be < to the subbuf_size, otherwise
	 * we won't be able to write the packets on disk
	 */
	if ((attr->attr.tracefile_size > 0) &&
			(attr->attr.tracefile_size < attr->attr.subbuf_size)) {
		ret = LTTNG_ERR_INVALID;
		goto error;
	}

	/* Validate buffer type. */
	switch (type) {
	case LTTNG_BUFFER_PER_PID:
		break;
	case LTTNG_BUFFER_PER_UID:
		break;
	default:
		ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
		goto error;
	}

	/* Create UST channel */
	uchan = trace_ust_create_channel(attr, domain);
	if (uchan == NULL) {
		ret = LTTNG_ERR_FATAL;
		goto error;
	}

	uchan->enabled = 1;
	if (trace_ust_is_max_id(usess->used_channel_id)) {
		ret = LTTNG_ERR_UST_CHAN_FAIL;
		goto error;
	}
	uchan->id = trace_ust_get_next_chan_id(usess);

	DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
			uchan->name, type, uchan->id);

	/* Flag session buffer type. */
	if (!usess->buffer_type_changed) {
		usess->buffer_type = type;
		usess->buffer_type_changed = 1;
	} else if (usess->buffer_type != type) {
		/* Buffer type was already set. Refuse to create channel. */
		ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
		goto error_free_chan;
	}

	/* Enable channel for global domain */
	ret = ust_app_create_channel_glb(usess, uchan);
	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
		ret = LTTNG_ERR_UST_CHAN_FAIL;
		goto error_free_chan;
	}

	/* Adding the channel to the channel hash table. */
	rcu_read_lock();
	if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
				sizeof(uchan->name))) {
		lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
		chan_published = true;
	} else {
		/*
		 * Copy channel attribute to session if this is metadata so if NO
		 * application exists we can access that data in the shadow copy during
		 * the global update of newly registered application.
		 */
		memcpy(&usess->metadata_attr, &uchan->attr,
				sizeof(usess->metadata_attr));
	}
	rcu_read_unlock();

	DBG2("Channel %s created successfully", uchan->name);
	if (domain != LTTNG_DOMAIN_UST) {
		struct agent *agt = trace_ust_find_agent(usess, domain);

		if (!agt) {
			agt = agent_create(domain);
			if (!agt) {
				ret = LTTNG_ERR_NOMEM;
				goto error_remove_chan;
			}
			agent_add(agt, usess->agents);
		}
	}

	channel_attr_destroy(defattr);
	return LTTNG_OK;

error_remove_chan:
	if (chan_published) {
		trace_ust_delete_channel(usess->domain_global.channels, uchan);
	}
error_free_chan:
	trace_ust_destroy_channel(uchan);
error:
	channel_attr_destroy(defattr);
	return ret;
}

/*
 * Disable UST channel for session and domain.
 */
int channel_ust_disable(struct ltt_ust_session *usess,
		struct ltt_ust_channel *uchan)
{
	int ret = LTTNG_OK;

	assert(usess);
	assert(uchan);

	/* Already disabled */
	if (uchan->enabled == 0) {
		DBG2("Channel UST %s already disabled", uchan->name);
		goto end;
	}

	DBG2("Channel %s being disabled in UST global domain", uchan->name);
	/* Disable channel for global domain */
	ret = ust_app_disable_channel_glb(usess, uchan);
	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
		ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
		goto error;
	}

	uchan->enabled = 0;

	DBG2("Channel %s disabled successfully", uchan->name);

	return LTTNG_OK;

end:
error:
	return ret;
}
Commit	Line	Data
54d01ffb DG	1	/*
54d01ffb DG	2	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
bdf64013	3	* Copyright (C) 2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
54d01ffb	4	*
d14d33bf AM	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License, version 2 only,
	7	* as published by the Free Software Foundation.
54d01ffb	8	*
d14d33bf AM	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
54d01ffb	13	*
d14d33bf AM	14	* You should have received a copy of the GNU General Public License along
	15	* with this program; if not, write to the Free Software Foundation, Inc.,
	16	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
54d01ffb DG	17	*/
54d01ffb DG	18
6c1c0768	19	#define _LGPL_SOURCE
7972aab2	20	#include <inttypes.h>
56fff090	21	#include <string.h>
54d01ffb DG	22	#include <unistd.h>
54d01ffb DG	23
990570ed DG	24	#include <common/common.h>
990570ed DG	25	#include <common/defaults.h>
db758600	26	#include <common/sessiond-comm/sessiond-comm.h>
54d01ffb DG	27
54d01ffb DG	28	#include "channel.h"
12744796	29	#include "lttng-sessiond.h"
4771f025	30	#include "kernel.h"
44d3bd01	31	#include "ust-ctl.h"
54d01ffb	32	#include "utils.h"
7885e399	33	#include "ust-app.h"
b63d638b	34	#include "agent.h"
54d01ffb DG	35
	36	/*
	37	* Return allocated channel attributes.
	38	*/
0a9c6494 DG	39	struct lttng_channel *channel_new_default_attr(int dom,
0a9c6494 DG	40	enum lttng_buffer_type type)
54d01ffb DG	41	{
54d01ffb DG	42	struct lttng_channel *chan;
bdf64013	43	const char *channel_name = DEFAULT_CHANNEL_NAME;
e9404c27	44	struct lttng_channel_extended *extended_attr = NULL;
54d01ffb DG	45
	46	chan = zmalloc(sizeof(struct lttng_channel));
	47	if (chan == NULL) {
7885e399	48	PERROR("zmalloc channel init");
54d01ffb DG	49	goto error_alloc;
	50	}
	51
e9404c27 JG	52	extended_attr = zmalloc(sizeof(struct lttng_channel_extended));
	53	if (!extended_attr) {
	54	PERROR("zmalloc channel extended init");
	55	goto error;
	56	}
	57
	58	chan->attr.extended.ptr = extended_attr;
	59
0a9c6494	60	/* Same for all domains. */
54d01ffb	61	chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
0a9c6494 DG	62	chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
0a9c6494 DG	63	chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
54d01ffb DG	64
54d01ffb DG	65	switch (dom) {
1b1c65fa	66	case LTTNG_DOMAIN_KERNEL:
0a9c6494	67	assert(type == LTTNG_BUFFER_GLOBAL);
3e230f92 SM	68	chan->attr.subbuf_size =
3e230f92 SM	69	default_get_kernel_channel_subbuf_size();
1b1c65fa MD	70	chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
1b1c65fa MD	71	chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
6bb9e85f MD	72	chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
6bb9e85f MD	73	chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
ecc48a90	74	chan->attr.live_timer_interval = DEFAULT_KERNEL_CHANNEL_LIVE_TIMER;
491d1539	75	extended_attr->blocking_timeout = DEFAULT_KERNEL_CHANNEL_BLOCKING_TIMEOUT;
e9404c27 JG	76	extended_attr->monitor_timer_interval =
e9404c27 JG	77	DEFAULT_KERNEL_CHANNEL_MONITOR_TIMER;
1b1c65fa	78	break;
bdf64013 JG	79	case LTTNG_DOMAIN_JUL:
	80	channel_name = DEFAULT_JUL_CHANNEL_NAME;
	81	goto common_ust;
	82	case LTTNG_DOMAIN_LOG4J:
	83	channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
	84	goto common_ust;
	85	case LTTNG_DOMAIN_PYTHON:
	86	channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
	87	goto common_ust;
1b1c65fa	88	case LTTNG_DOMAIN_UST:
bdf64013	89	common_ust:
0a9c6494 DG	90	switch (type) {
	91	case LTTNG_BUFFER_PER_UID:
	92	chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
	93	chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
	94	chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
	95	chan->attr.switch_timer_interval =
	96	DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
	97	chan->attr.read_timer_interval =
	98	DEFAULT_UST_UID_CHANNEL_READ_TIMER;
ecc48a90 JD	99	chan->attr.live_timer_interval =
ecc48a90 JD	100	DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
491d1539	101	extended_attr->blocking_timeout = DEFAULT_UST_UID_CHANNEL_BLOCKING_TIMEOUT;
e9404c27 JG	102	extended_attr->monitor_timer_interval =
e9404c27 JG	103	DEFAULT_UST_UID_CHANNEL_MONITOR_TIMER;
0a9c6494 DG	104	break;
	105	case LTTNG_BUFFER_PER_PID:
	106	default:
	107	chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
	108	chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
	109	chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
	110	chan->attr.switch_timer_interval =
	111	DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
	112	chan->attr.read_timer_interval =
	113	DEFAULT_UST_PID_CHANNEL_READ_TIMER;
ecc48a90	114	chan->attr.live_timer_interval =
e9404c27	115	DEFAULT_UST_PID_CHANNEL_LIVE_TIMER;
491d1539	116	extended_attr->blocking_timeout = DEFAULT_UST_PID_CHANNEL_BLOCKING_TIMEOUT;
e9404c27 JG	117	extended_attr->monitor_timer_interval =
e9404c27 JG	118	DEFAULT_UST_PID_CHANNEL_MONITOR_TIMER;
0a9c6494 DG	119	break;
0a9c6494 DG	120	}
1b1c65fa MD	121	break;
	122	default:
	123	goto error; /* Not implemented */
54d01ffb DG	124	}
54d01ffb DG	125
bdf64013 JG	126	if (snprintf(chan->name, sizeof(chan->name), "%s",
	127	channel_name) < 0) {
	128	PERROR("snprintf default channel name");
	129	goto error;
	130	}
54d01ffb DG	131	return chan;
	132
	133	error:
e9404c27	134	free(extended_attr);
54d01ffb DG	135	free(chan);
	136	error_alloc:
	137	return NULL;
	138	}
	139
e9404c27 JG	140	void channel_attr_destroy(struct lttng_channel *channel)
	141	{
	142	if (!channel) {
	143	return;
	144	}
	145	free(channel->attr.extended.ptr);
	146	free(channel);
	147	}
	148
54d01ffb DG	149	/*
	150	* Disable kernel channel of the kernel session.
	151	*/
	152	int channel_kernel_disable(struct ltt_kernel_session *ksession,
	153	char *channel_name)
	154	{
	155	int ret;
	156	struct ltt_kernel_channel *kchan;
	157
0525e9ae DG	158	assert(ksession);
	159	assert(channel_name);
	160
54d01ffb DG	161	kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
54d01ffb DG	162	if (kchan == NULL) {
f73fabfd	163	ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
54d01ffb	164	goto error;
0525e9ae DG	165	}
	166
	167	/* Only if channel is enabled disable it. */
	168	if (kchan->enabled == 1) {
54d01ffb	169	ret = kernel_disable_channel(kchan);
7885e399	170	if (ret < 0 && ret != -EEXIST) {
f73fabfd	171	ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
54d01ffb DG	172	goto error;
	173	}
	174	}
	175
f73fabfd	176	ret = LTTNG_OK;
54d01ffb DG	177
	178	error:
	179	return ret;
	180	}
	181
	182	/*
	183	* Enable kernel channel of the kernel session.
	184	*/
	185	int channel_kernel_enable(struct ltt_kernel_session *ksession,
	186	struct ltt_kernel_channel *kchan)
	187	{
	188	int ret;
	189
0525e9ae DG	190	assert(ksession);
	191	assert(kchan);
	192
54d01ffb DG	193	if (kchan->enabled == 0) {
	194	ret = kernel_enable_channel(kchan);
	195	if (ret < 0) {
f73fabfd	196	ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
54d01ffb DG	197	goto error;
54d01ffb DG	198	}
42224349	199	} else {
f73fabfd	200	ret = LTTNG_ERR_KERN_CHAN_EXIST;
42224349	201	goto error;
54d01ffb DG	202	}
54d01ffb DG	203
f73fabfd	204	ret = LTTNG_OK;
54d01ffb DG	205
	206	error:
	207	return ret;
	208	}
	209
da9d9d9c MD	210	static int channel_validate(struct lttng_channel *attr)
	211	{
	212	/*
	213	* The ringbuffer (both in user space and kernel) behaves badly
	214	* in overwrite mode and with less than 2 subbuffers so block it
	215	* right away and send back an invalid attribute error.
	216	*/
	217	if (attr->attr.overwrite && attr->attr.num_subbuf < 2) {
	218	return -1;
	219	}
	220	return 0;
	221	}
	222
491d1539 MD	223	static int channel_validate_kernel(struct lttng_channel *attr)
	224	{
	225	/* Kernel channels do not support blocking timeout. */
	226	if (((struct lttng_channel_extended *)attr->attr.extended.ptr)->blocking_timeout) {
	227	return -1;
	228	}
	229	return 0;
	230	}
	231
54d01ffb DG	232	/*
	233	* Create kernel channel of the kernel session and notify kernel thread.
	234	*/
	235	int channel_kernel_create(struct ltt_kernel_session *ksession,
ff4d74e6	236	struct lttng_channel *attr, int kernel_pipe)
54d01ffb DG	237	{
54d01ffb DG	238	int ret;
ff4d74e6	239	struct lttng_channel *defattr = NULL;
54d01ffb	240
0525e9ae DG	241	assert(ksession);
0525e9ae DG	242
54d01ffb DG	243	/* Creating channel attributes if needed */
54d01ffb DG	244	if (attr == NULL) {
0a9c6494 DG	245	defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
0a9c6494 DG	246	LTTNG_BUFFER_GLOBAL);
ff4d74e6	247	if (defattr == NULL) {
f73fabfd	248	ret = LTTNG_ERR_FATAL;
54d01ffb DG	249	goto error;
54d01ffb DG	250	}
ff4d74e6	251	attr = defattr;
54d01ffb DG	252	}
54d01ffb DG	253
8d5841ea MD	254	/*
	255	* Set the overwrite mode for this channel based on the session
	256	* type unless the client explicitly overrides the channel mode.
	257	*/
	258	if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
	259	attr->attr.overwrite = !!ksession->snapshot_mode;
	260	}
	261
	262	/* Enforce mmap output for snapshot sessions. */
27babd3a	263	if (ksession->snapshot_mode) {
27babd3a DG	264	attr->attr.output = LTTNG_EVENT_MMAP;
	265	}
	266
da9d9d9c MD	267	/* Validate common channel properties. */
	268	if (channel_validate(attr) < 0) {
	269	ret = LTTNG_ERR_INVALID;
	270	goto error;
	271	}
	272
491d1539 MD	273	if (channel_validate_kernel(attr) < 0) {
	274	ret = LTTNG_ERR_INVALID;
	275	goto error;
	276	}
	277
54d01ffb	278	/* Channel not found, creating it */
fdd9eb17	279	ret = kernel_create_channel(ksession, attr);
54d01ffb	280	if (ret < 0) {
f73fabfd	281	ret = LTTNG_ERR_KERN_CHAN_FAIL;
54d01ffb DG	282	goto error;
	283	}
	284
	285	/* Notify kernel thread that there is a new channel */
	286	ret = notify_thread_pipe(kernel_pipe);
	287	if (ret < 0) {
f73fabfd	288	ret = LTTNG_ERR_FATAL;
54d01ffb DG	289	goto error;
	290	}
	291
f73fabfd	292	ret = LTTNG_OK;
54d01ffb	293	error:
e9404c27	294	channel_attr_destroy(defattr);
54d01ffb DG	295	return ret;
54d01ffb DG	296	}
7885e399 DG	297
	298	/*
	299	* Enable UST channel for session and domain.
	300	*/
7972aab2	301	int channel_ust_enable(struct ltt_ust_session *usess,
7885e399 DG	302	struct ltt_ust_channel *uchan)
7885e399 DG	303	{
f73fabfd	304	int ret = LTTNG_OK;
7885e399	305
0525e9ae DG	306	assert(usess);
	307	assert(uchan);
	308
7885e399 DG	309	/* If already enabled, everything is OK */
	310	if (uchan->enabled) {
	311	DBG3("Channel %s already enabled. Skipping", uchan->name);
f73fabfd	312	ret = LTTNG_ERR_UST_CHAN_EXIST;
7885e399 DG	313	goto end;
	314	}
	315
7972aab2 DG	316	DBG2("Channel %s being enabled in UST domain", uchan->name);
	317
	318	/*
	319	* Enable channel for UST global domain on all applications. Ignore return
	320	* value here since whatever error we got, it means that the channel was
	321	* not created on one or many registered applications and we can not report
	322	* this to the user yet. However, at this stage, the channel was
	323	* successfully created on the session daemon side so the enable-channel
	324	* command is a success.
	325	*/
d54b4440	326	(void) ust_app_enable_channel_glb(usess, uchan);
7885e399	327
7885e399 DG	328	uchan->enabled = 1;
	329	DBG2("Channel %s enabled successfully", uchan->name);
	330
	331	end:
7885e399 DG	332	return ret;
	333	}
	334
	335	/*
	336	* Create UST channel for session and domain.
	337	*/
7972aab2 DG	338	int channel_ust_create(struct ltt_ust_session *usess,
7972aab2 DG	339	struct lttng_channel *attr, enum lttng_buffer_type type)
7885e399	340	{
f73fabfd	341	int ret = LTTNG_OK;
7885e399 DG	342	struct ltt_ust_channel *uchan = NULL;
7885e399 DG	343	struct lttng_channel *defattr = NULL;
b63d638b	344	enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
f86e086c	345	bool chan_published = false;
7885e399	346
0525e9ae DG	347	assert(usess);
0525e9ae DG	348
7885e399 DG	349	/* Creating channel attributes if needed */
7885e399 DG	350	if (attr == NULL) {
0a9c6494	351	defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
7885e399	352	if (defattr == NULL) {
f73fabfd	353	ret = LTTNG_ERR_FATAL;
7885e399 DG	354	goto error;
	355	}
	356	attr = defattr;
b63d638b JG	357	} else {
	358	/*
	359	* HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
	360	* based on the default name.
	361	*/
	362	if (!strcmp(attr->name, DEFAULT_JUL_CHANNEL_NAME)) {
	363	domain = LTTNG_DOMAIN_JUL;
	364	} else if (!strcmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
	365	domain = LTTNG_DOMAIN_LOG4J;
	366	} else if (!strcmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
	367	domain = LTTNG_DOMAIN_PYTHON;
	368	}
7885e399 DG	369	}
7885e399 DG	370
8d5841ea MD	371	/*
	372	* Set the overwrite mode for this channel based on the session
	373	* type unless the client explicitly overrides the channel mode.
	374	*/
	375	if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
	376	attr->attr.overwrite = !!usess->snapshot_mode;
	377	}
	378
	379	/* Enforce mmap output for snapshot sessions. */
27babd3a	380	if (usess->snapshot_mode) {
27babd3a DG	381	attr->attr.output = LTTNG_EVENT_MMAP;
	382	}
	383
da9d9d9c MD	384	/* Validate common channel properties. */
	385	if (channel_validate(attr) < 0) {
	386	ret = LTTNG_ERR_INVALID;
	387	goto error;
	388	}
	389
b024d072	390	/*
0525e9ae DG	391	* Validate UST buffer size and number of buffers: must both be power of 2
	392	* and nonzero. We validate right here for UST, because applications will
	393	* not report the error to the user (unlike kernel tracing).
b024d072	394	*/
0525e9ae DG	395	if (!attr->attr.subbuf_size \|\|
0525e9ae DG	396	(attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
f73fabfd	397	ret = LTTNG_ERR_INVALID;
b024d072 MD	398	goto error;
b024d072 MD	399	}
0525e9ae	400
12744796 DG	401	/*
	402	* Invalid subbuffer size if it's lower then the page size.
	403	*/
	404	if (attr->attr.subbuf_size < page_size) {
	405	ret = LTTNG_ERR_INVALID;
	406	goto error;
	407	}
	408
0525e9ae DG	409	if (!attr->attr.num_subbuf \|\|
0525e9ae DG	410	(attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
f73fabfd	411	ret = LTTNG_ERR_INVALID;
b024d072 MD	412	goto error;
	413	}
	414
a79d84dd DG	415	if (attr->attr.output != LTTNG_EVENT_MMAP) {
	416	ret = LTTNG_ERR_NOT_SUPPORTED;
	417	goto error;
	418	}
	419
1624d5b7 JD	420	/*
	421	* The tracefile_size should not be < to the subbuf_size, otherwise
	422	* we won't be able to write the packets on disk
	423	*/
	424	if ((attr->attr.tracefile_size > 0) &&
	425	(attr->attr.tracefile_size < attr->attr.subbuf_size)) {
	426	ret = LTTNG_ERR_INVALID;
	427	goto error;
	428	}
	429
2e8269f7 DG	430	/* Validate buffer type. */
	431	switch (type) {
	432	case LTTNG_BUFFER_PER_PID:
0a9c6494	433	break;
2e8269f7 DG	434	case LTTNG_BUFFER_PER_UID:
	435	break;
	436	default:
	437	ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
	438	goto error;
	439	}
	440
7885e399	441	/* Create UST channel */
b63d638b	442	uchan = trace_ust_create_channel(attr, domain);
7885e399	443	if (uchan == NULL) {
f73fabfd	444	ret = LTTNG_ERR_FATAL;
7885e399 DG	445	goto error;
7885e399 DG	446	}
51755dc8	447
58f3ca76	448	uchan->enabled = 1;
7972aab2 DG	449	if (trace_ust_is_max_id(usess->used_channel_id)) {
	450	ret = LTTNG_ERR_UST_CHAN_FAIL;
	451	goto error;
	452	}
	453	uchan->id = trace_ust_get_next_chan_id(usess);
	454
	455	DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
	456	uchan->name, type, uchan->id);
	457
	458	/* Flag session buffer type. */
	459	if (!usess->buffer_type_changed) {
	460	usess->buffer_type = type;
	461	usess->buffer_type_changed = 1;
	462	} else if (usess->buffer_type != type) {
	463	/* Buffer type was already set. Refuse to create channel. */
	464	ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
7885e399 DG	465	goto error_free_chan;
	466	}
	467
7972aab2 DG	468	/* Enable channel for global domain */
7972aab2 DG	469	ret = ust_app_create_channel_glb(usess, uchan);
49c336c1	470	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
f73fabfd	471	ret = LTTNG_ERR_UST_CHAN_FAIL;
7885e399 DG	472	goto error_free_chan;
	473	}
	474
fc34caaa DG	475	/* Adding the channel to the channel hash table. */
fc34caaa DG	476	rcu_read_lock();
ad7a9107 DG	477	if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
	478	sizeof(uchan->name))) {
	479	lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
f86e086c	480	chan_published = true;
84ad93e8 DG	481	} else {
	482	/*
	483	* Copy channel attribute to session if this is metadata so if NO
	484	* application exists we can access that data in the shadow copy during
	485	* the global update of newly registered application.
	486	*/
	487	memcpy(&usess->metadata_attr, &uchan->attr,
	488	sizeof(usess->metadata_attr));
ad7a9107	489	}
fc34caaa DG	490	rcu_read_unlock();
fc34caaa DG	491
7885e399	492	DBG2("Channel %s created successfully", uchan->name);
b63d638b JG	493	if (domain != LTTNG_DOMAIN_UST) {
	494	struct agent *agt = trace_ust_find_agent(usess, domain);
	495
	496	if (!agt) {
	497	agt = agent_create(domain);
	498	if (!agt) {
	499	ret = LTTNG_ERR_NOMEM;
f86e086c	500	goto error_remove_chan;
b63d638b JG	501	}
	502	agent_add(agt, usess->agents);
	503	}
	504	}
7885e399	505
e9404c27	506	channel_attr_destroy(defattr);
f73fabfd	507	return LTTNG_OK;
7885e399	508
f86e086c MD	509	error_remove_chan:
	510	if (chan_published) {
	511	trace_ust_delete_channel(usess->domain_global.channels, uchan);
	512	}
7885e399 DG	513	error_free_chan:
	514	trace_ust_destroy_channel(uchan);
	515	error:
e9404c27	516	channel_attr_destroy(defattr);
7885e399 DG	517	return ret;
	518	}
	519
	520	/*
	521	* Disable UST channel for session and domain.
	522	*/
7972aab2	523	int channel_ust_disable(struct ltt_ust_session *usess,
7885e399 DG	524	struct ltt_ust_channel *uchan)
7885e399 DG	525	{
f73fabfd	526	int ret = LTTNG_OK;
7885e399	527
0525e9ae DG	528	assert(usess);
	529	assert(uchan);
	530
7885e399 DG	531	/* Already disabled */
	532	if (uchan->enabled == 0) {
	533	DBG2("Channel UST %s already disabled", uchan->name);
	534	goto end;
	535	}
	536
7972aab2 DG	537	DBG2("Channel %s being disabled in UST global domain", uchan->name);
	538	/* Disable channel for global domain */
	539	ret = ust_app_disable_channel_glb(usess, uchan);
49c336c1	540	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
f73fabfd	541	ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
7885e399 DG	542	goto error;
	543	}
	544
	545	uchan->enabled = 0;
	546
	547	DBG2("Channel %s disabled successfully", uchan->name);
	548
f73fabfd	549	return LTTNG_OK;
7885e399 DG	550
	551	end:
	552	error:
	553	return ret;
	554	}