[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->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->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->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;
}

/*
 * 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;
	}

	/* 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;

	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);
	} 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_free_chan;
			}
			agent_add(agt, usess->agents);
		}
	}

	channel_attr_destroy(defattr);
	return LTTNG_OK;

error_free_chan:
	/*
	 * No need to remove the channel from the hash table because at this point
	 * it was not added hence the direct call and no call_rcu().
	 */
	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;
e9404c27 JG	75	extended_attr->monitor_timer_interval =
e9404c27 JG	76	DEFAULT_KERNEL_CHANNEL_MONITOR_TIMER;
1b1c65fa	77	break;
bdf64013 JG	78	case LTTNG_DOMAIN_JUL:
	79	channel_name = DEFAULT_JUL_CHANNEL_NAME;
	80	goto common_ust;
	81	case LTTNG_DOMAIN_LOG4J:
	82	channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
	83	goto common_ust;
	84	case LTTNG_DOMAIN_PYTHON:
	85	channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
	86	goto common_ust;
1b1c65fa	87	case LTTNG_DOMAIN_UST:
bdf64013	88	common_ust:
0a9c6494 DG	89	switch (type) {
	90	case LTTNG_BUFFER_PER_UID:
	91	chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
	92	chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
	93	chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
	94	chan->attr.switch_timer_interval =
	95	DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
	96	chan->attr.read_timer_interval =
	97	DEFAULT_UST_UID_CHANNEL_READ_TIMER;
ecc48a90 JD	98	chan->attr.live_timer_interval =
ecc48a90 JD	99	DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
e9404c27 JG	100	extended_attr->monitor_timer_interval =
e9404c27 JG	101	DEFAULT_UST_UID_CHANNEL_MONITOR_TIMER;
0a9c6494 DG	102	break;
	103	case LTTNG_BUFFER_PER_PID:
	104	default:
	105	chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
	106	chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
	107	chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
	108	chan->attr.switch_timer_interval =
	109	DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
	110	chan->attr.read_timer_interval =
	111	DEFAULT_UST_PID_CHANNEL_READ_TIMER;
ecc48a90	112	chan->attr.live_timer_interval =
e9404c27 JG	113	DEFAULT_UST_PID_CHANNEL_LIVE_TIMER;
	114	extended_attr->monitor_timer_interval =
	115	DEFAULT_UST_PID_CHANNEL_MONITOR_TIMER;
0a9c6494 DG	116	break;
0a9c6494 DG	117	}
1b1c65fa MD	118	break;
	119	default:
	120	goto error; /* Not implemented */
54d01ffb DG	121	}
54d01ffb DG	122
bdf64013 JG	123	if (snprintf(chan->name, sizeof(chan->name), "%s",
	124	channel_name) < 0) {
	125	PERROR("snprintf default channel name");
	126	goto error;
	127	}
54d01ffb DG	128	return chan;
	129
	130	error:
e9404c27	131	free(extended_attr);
54d01ffb DG	132	free(chan);
	133	error_alloc:
	134	return NULL;
	135	}
	136
e9404c27 JG	137	void channel_attr_destroy(struct lttng_channel *channel)
	138	{
	139	if (!channel) {
	140	return;
	141	}
	142	free(channel->attr.extended.ptr);
	143	free(channel);
	144	}
	145
54d01ffb DG	146	/*
	147	* Disable kernel channel of the kernel session.
	148	*/
	149	int channel_kernel_disable(struct ltt_kernel_session *ksession,
	150	char *channel_name)
	151	{
	152	int ret;
	153	struct ltt_kernel_channel *kchan;
	154
0525e9ae DG	155	assert(ksession);
	156	assert(channel_name);
	157
54d01ffb DG	158	kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
54d01ffb DG	159	if (kchan == NULL) {
f73fabfd	160	ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
54d01ffb	161	goto error;
0525e9ae DG	162	}
	163
	164	/* Only if channel is enabled disable it. */
	165	if (kchan->enabled == 1) {
54d01ffb	166	ret = kernel_disable_channel(kchan);
7885e399	167	if (ret < 0 && ret != -EEXIST) {
f73fabfd	168	ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
54d01ffb DG	169	goto error;
	170	}
	171	}
	172
f73fabfd	173	ret = LTTNG_OK;
54d01ffb DG	174
	175	error:
	176	return ret;
	177	}
	178
	179	/*
	180	* Enable kernel channel of the kernel session.
	181	*/
	182	int channel_kernel_enable(struct ltt_kernel_session *ksession,
	183	struct ltt_kernel_channel *kchan)
	184	{
	185	int ret;
	186
0525e9ae DG	187	assert(ksession);
	188	assert(kchan);
	189
54d01ffb DG	190	if (kchan->enabled == 0) {
	191	ret = kernel_enable_channel(kchan);
	192	if (ret < 0) {
f73fabfd	193	ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
54d01ffb DG	194	goto error;
54d01ffb DG	195	}
42224349	196	} else {
f73fabfd	197	ret = LTTNG_ERR_KERN_CHAN_EXIST;
42224349	198	goto error;
54d01ffb DG	199	}
54d01ffb DG	200
f73fabfd	201	ret = LTTNG_OK;
54d01ffb DG	202
	203	error:
	204	return ret;
	205	}
	206
da9d9d9c MD	207	static int channel_validate(struct lttng_channel *attr)
	208	{
	209	/*
	210	* The ringbuffer (both in user space and kernel) behaves badly
	211	* in overwrite mode and with less than 2 subbuffers so block it
	212	* right away and send back an invalid attribute error.
	213	*/
	214	if (attr->attr.overwrite && attr->attr.num_subbuf < 2) {
	215	return -1;
	216	}
	217	return 0;
	218	}
	219
54d01ffb DG	220	/*
	221	* Create kernel channel of the kernel session and notify kernel thread.
	222	*/
	223	int channel_kernel_create(struct ltt_kernel_session *ksession,
ff4d74e6	224	struct lttng_channel *attr, int kernel_pipe)
54d01ffb DG	225	{
54d01ffb DG	226	int ret;
ff4d74e6	227	struct lttng_channel *defattr = NULL;
54d01ffb	228
0525e9ae DG	229	assert(ksession);
0525e9ae DG	230
54d01ffb DG	231	/* Creating channel attributes if needed */
54d01ffb DG	232	if (attr == NULL) {
0a9c6494 DG	233	defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
0a9c6494 DG	234	LTTNG_BUFFER_GLOBAL);
ff4d74e6	235	if (defattr == NULL) {
f73fabfd	236	ret = LTTNG_ERR_FATAL;
54d01ffb DG	237	goto error;
54d01ffb DG	238	}
ff4d74e6	239	attr = defattr;
54d01ffb DG	240	}
54d01ffb DG	241
8d5841ea MD	242	/*
	243	* Set the overwrite mode for this channel based on the session
	244	* type unless the client explicitly overrides the channel mode.
	245	*/
	246	if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
	247	attr->attr.overwrite = !!ksession->snapshot_mode;
	248	}
	249
	250	/* Enforce mmap output for snapshot sessions. */
27babd3a	251	if (ksession->snapshot_mode) {
27babd3a DG	252	attr->attr.output = LTTNG_EVENT_MMAP;
	253	}
	254
da9d9d9c MD	255	/* Validate common channel properties. */
	256	if (channel_validate(attr) < 0) {
	257	ret = LTTNG_ERR_INVALID;
	258	goto error;
	259	}
	260
54d01ffb	261	/* Channel not found, creating it */
fdd9eb17	262	ret = kernel_create_channel(ksession, attr);
54d01ffb	263	if (ret < 0) {
f73fabfd	264	ret = LTTNG_ERR_KERN_CHAN_FAIL;
54d01ffb DG	265	goto error;
	266	}
	267
	268	/* Notify kernel thread that there is a new channel */
	269	ret = notify_thread_pipe(kernel_pipe);
	270	if (ret < 0) {
f73fabfd	271	ret = LTTNG_ERR_FATAL;
54d01ffb DG	272	goto error;
	273	}
	274
f73fabfd	275	ret = LTTNG_OK;
54d01ffb	276	error:
e9404c27	277	channel_attr_destroy(defattr);
54d01ffb DG	278	return ret;
54d01ffb DG	279	}
7885e399 DG	280
	281	/*
	282	* Enable UST channel for session and domain.
	283	*/
7972aab2	284	int channel_ust_enable(struct ltt_ust_session *usess,
7885e399 DG	285	struct ltt_ust_channel *uchan)
7885e399 DG	286	{
f73fabfd	287	int ret = LTTNG_OK;
7885e399	288
0525e9ae DG	289	assert(usess);
	290	assert(uchan);
	291
7885e399 DG	292	/* If already enabled, everything is OK */
	293	if (uchan->enabled) {
	294	DBG3("Channel %s already enabled. Skipping", uchan->name);
f73fabfd	295	ret = LTTNG_ERR_UST_CHAN_EXIST;
7885e399 DG	296	goto end;
	297	}
	298
7972aab2 DG	299	DBG2("Channel %s being enabled in UST domain", uchan->name);
	300
	301	/*
	302	* Enable channel for UST global domain on all applications. Ignore return
	303	* value here since whatever error we got, it means that the channel was
	304	* not created on one or many registered applications and we can not report
	305	* this to the user yet. However, at this stage, the channel was
	306	* successfully created on the session daemon side so the enable-channel
	307	* command is a success.
	308	*/
d54b4440	309	(void) ust_app_enable_channel_glb(usess, uchan);
7885e399	310
7885e399 DG	311	uchan->enabled = 1;
	312	DBG2("Channel %s enabled successfully", uchan->name);
	313
	314	end:
7885e399 DG	315	return ret;
	316	}
	317
	318	/*
	319	* Create UST channel for session and domain.
	320	*/
7972aab2 DG	321	int channel_ust_create(struct ltt_ust_session *usess,
7972aab2 DG	322	struct lttng_channel *attr, enum lttng_buffer_type type)
7885e399	323	{
f73fabfd	324	int ret = LTTNG_OK;
7885e399 DG	325	struct ltt_ust_channel *uchan = NULL;
7885e399 DG	326	struct lttng_channel *defattr = NULL;
b63d638b	327	enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
7885e399	328
0525e9ae DG	329	assert(usess);
0525e9ae DG	330
7885e399 DG	331	/* Creating channel attributes if needed */
7885e399 DG	332	if (attr == NULL) {
0a9c6494	333	defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
7885e399	334	if (defattr == NULL) {
f73fabfd	335	ret = LTTNG_ERR_FATAL;
7885e399 DG	336	goto error;
	337	}
	338	attr = defattr;
b63d638b JG	339	} else {
	340	/*
	341	* HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
	342	* based on the default name.
	343	*/
	344	if (!strcmp(attr->name, DEFAULT_JUL_CHANNEL_NAME)) {
	345	domain = LTTNG_DOMAIN_JUL;
	346	} else if (!strcmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
	347	domain = LTTNG_DOMAIN_LOG4J;
	348	} else if (!strcmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
	349	domain = LTTNG_DOMAIN_PYTHON;
	350	}
7885e399 DG	351	}
7885e399 DG	352
8d5841ea MD	353	/*
	354	* Set the overwrite mode for this channel based on the session
	355	* type unless the client explicitly overrides the channel mode.
	356	*/
	357	if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
	358	attr->attr.overwrite = !!usess->snapshot_mode;
	359	}
	360
	361	/* Enforce mmap output for snapshot sessions. */
27babd3a	362	if (usess->snapshot_mode) {
27babd3a DG	363	attr->attr.output = LTTNG_EVENT_MMAP;
	364	}
	365
da9d9d9c MD	366	/* Validate common channel properties. */
	367	if (channel_validate(attr) < 0) {
	368	ret = LTTNG_ERR_INVALID;
	369	goto error;
	370	}
	371
b024d072	372	/*
0525e9ae DG	373	* Validate UST buffer size and number of buffers: must both be power of 2
	374	* and nonzero. We validate right here for UST, because applications will
	375	* not report the error to the user (unlike kernel tracing).
b024d072	376	*/
0525e9ae DG	377	if (!attr->attr.subbuf_size \|\|
0525e9ae DG	378	(attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
f73fabfd	379	ret = LTTNG_ERR_INVALID;
b024d072 MD	380	goto error;
b024d072 MD	381	}
0525e9ae	382
12744796 DG	383	/*
	384	* Invalid subbuffer size if it's lower then the page size.
	385	*/
	386	if (attr->attr.subbuf_size < page_size) {
	387	ret = LTTNG_ERR_INVALID;
	388	goto error;
	389	}
	390
0525e9ae DG	391	if (!attr->attr.num_subbuf \|\|
0525e9ae DG	392	(attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
f73fabfd	393	ret = LTTNG_ERR_INVALID;
b024d072 MD	394	goto error;
	395	}
	396
a79d84dd DG	397	if (attr->attr.output != LTTNG_EVENT_MMAP) {
	398	ret = LTTNG_ERR_NOT_SUPPORTED;
	399	goto error;
	400	}
	401
1624d5b7 JD	402	/*
	403	* The tracefile_size should not be < to the subbuf_size, otherwise
	404	* we won't be able to write the packets on disk
	405	*/
	406	if ((attr->attr.tracefile_size > 0) &&
	407	(attr->attr.tracefile_size < attr->attr.subbuf_size)) {
	408	ret = LTTNG_ERR_INVALID;
	409	goto error;
	410	}
	411
2e8269f7 DG	412	/* Validate buffer type. */
	413	switch (type) {
	414	case LTTNG_BUFFER_PER_PID:
0a9c6494	415	break;
2e8269f7 DG	416	case LTTNG_BUFFER_PER_UID:
	417	break;
	418	default:
	419	ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
	420	goto error;
	421	}
	422
7885e399	423	/* Create UST channel */
b63d638b	424	uchan = trace_ust_create_channel(attr, domain);
7885e399	425	if (uchan == NULL) {
f73fabfd	426	ret = LTTNG_ERR_FATAL;
7885e399 DG	427	goto error;
7885e399 DG	428	}
51755dc8	429
58f3ca76	430	uchan->enabled = 1;
7972aab2 DG	431	if (trace_ust_is_max_id(usess->used_channel_id)) {
	432	ret = LTTNG_ERR_UST_CHAN_FAIL;
	433	goto error;
	434	}
	435	uchan->id = trace_ust_get_next_chan_id(usess);
	436
	437	DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
	438	uchan->name, type, uchan->id);
	439
	440	/* Flag session buffer type. */
	441	if (!usess->buffer_type_changed) {
	442	usess->buffer_type = type;
	443	usess->buffer_type_changed = 1;
	444	} else if (usess->buffer_type != type) {
	445	/* Buffer type was already set. Refuse to create channel. */
	446	ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
7885e399 DG	447	goto error_free_chan;
	448	}
	449
7972aab2 DG	450	/* Enable channel for global domain */
7972aab2 DG	451	ret = ust_app_create_channel_glb(usess, uchan);
49c336c1	452	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
f73fabfd	453	ret = LTTNG_ERR_UST_CHAN_FAIL;
7885e399 DG	454	goto error_free_chan;
	455	}
	456
fc34caaa DG	457	/* Adding the channel to the channel hash table. */
fc34caaa DG	458	rcu_read_lock();
ad7a9107 DG	459	if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
	460	sizeof(uchan->name))) {
	461	lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
84ad93e8 DG	462	} else {
	463	/*
	464	* Copy channel attribute to session if this is metadata so if NO
	465	* application exists we can access that data in the shadow copy during
	466	* the global update of newly registered application.
	467	*/
	468	memcpy(&usess->metadata_attr, &uchan->attr,
	469	sizeof(usess->metadata_attr));
ad7a9107	470	}
fc34caaa DG	471	rcu_read_unlock();
fc34caaa DG	472
7885e399	473	DBG2("Channel %s created successfully", uchan->name);
b63d638b JG	474	if (domain != LTTNG_DOMAIN_UST) {
	475	struct agent *agt = trace_ust_find_agent(usess, domain);
	476
	477	if (!agt) {
	478	agt = agent_create(domain);
	479	if (!agt) {
	480	ret = LTTNG_ERR_NOMEM;
	481	goto error_free_chan;
	482	}
	483	agent_add(agt, usess->agents);
	484	}
	485	}
7885e399	486
e9404c27	487	channel_attr_destroy(defattr);
f73fabfd	488	return LTTNG_OK;
7885e399 DG	489
7885e399 DG	490	error_free_chan:
24d1723f DG	491	/*
	492	* No need to remove the channel from the hash table because at this point
	493	* it was not added hence the direct call and no call_rcu().
	494	*/
7885e399 DG	495	trace_ust_destroy_channel(uchan);
7885e399 DG	496	error:
e9404c27	497	channel_attr_destroy(defattr);
7885e399 DG	498	return ret;
	499	}
	500
	501	/*
	502	* Disable UST channel for session and domain.
	503	*/
7972aab2	504	int channel_ust_disable(struct ltt_ust_session *usess,
7885e399 DG	505	struct ltt_ust_channel *uchan)
7885e399 DG	506	{
f73fabfd	507	int ret = LTTNG_OK;
7885e399	508
0525e9ae DG	509	assert(usess);
	510	assert(uchan);
	511
7885e399 DG	512	/* Already disabled */
	513	if (uchan->enabled == 0) {
	514	DBG2("Channel UST %s already disabled", uchan->name);
	515	goto end;
	516	}
	517
7972aab2 DG	518	DBG2("Channel %s being disabled in UST global domain", uchan->name);
	519	/* Disable channel for global domain */
	520	ret = ust_app_disable_channel_glb(usess, uchan);
49c336c1	521	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
f73fabfd	522	ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
7885e399 DG	523	goto error;
	524	}
	525
	526	uchan->enabled = 0;
	527
	528	DBG2("Channel %s disabled successfully", uchan->name);
	529
f73fabfd	530	return LTTNG_OK;
7885e399 DG	531
	532	end:
	533	error:
	534	return ret;
	535	}