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

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *
 * 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 _GNU_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"

/*
 * Return allocated channel attributes.
 */
struct lttng_channel *channel_new_default_attr(int dom,
		enum lttng_buffer_type type)
{
	struct lttng_channel *chan;

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

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

	/* 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;
		break;
	case LTTNG_DOMAIN_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;
			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;
			break;
		}
		break;
	default:
		goto error;	/* Not implemented */
	}

	return chan;

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

/*
 * 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;
}

/*
 * 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;
	}

	if (ksession->snapshot_mode) {
		/* Force channel attribute for snapshot mode. */
		attr->attr.overwrite = 1;
		attr->attr.output = LTTNG_EVENT_MMAP;
	}

	/* 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:
	free(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;

	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;
	}

	if (usess->snapshot_mode) {
		/* Force channel attribute for snapshot mode. */
		attr->attr.overwrite = 1;
		attr->attr.output = LTTNG_EVENT_MMAP;
	}

	/*
	 * 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);
	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();
	lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
	rcu_read_unlock();

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

	free(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:
	free(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	/*
	2	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
	3	*
d14d33bf AM	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License, version 2 only,
	6	* as published by the Free Software Foundation.
54d01ffb	7	*
d14d33bf AM	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	* GNU General Public License for more details.
54d01ffb	12	*
d14d33bf AM	13	* You should have received a copy of the GNU General Public License along
	14	* with this program; if not, write to the Free Software Foundation, Inc.,
	15	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
54d01ffb DG	16	*/
54d01ffb DG	17
7885e399	18	#define _GNU_SOURCE
7972aab2	19	#include <inttypes.h>
56fff090	20	#include <string.h>
54d01ffb DG	21	#include <unistd.h>
54d01ffb DG	22
990570ed DG	23	#include <common/common.h>
990570ed DG	24	#include <common/defaults.h>
db758600	25	#include <common/sessiond-comm/sessiond-comm.h>
54d01ffb DG	26
54d01ffb DG	27	#include "channel.h"
12744796	28	#include "lttng-sessiond.h"
4771f025	29	#include "kernel.h"
44d3bd01	30	#include "ust-ctl.h"
54d01ffb	31	#include "utils.h"
7885e399	32	#include "ust-app.h"
54d01ffb DG	33
	34	/*
	35	* Return allocated channel attributes.
	36	*/
0a9c6494 DG	37	struct lttng_channel *channel_new_default_attr(int dom,
0a9c6494 DG	38	enum lttng_buffer_type type)
54d01ffb DG	39	{
	40	struct lttng_channel *chan;
	41
	42	chan = zmalloc(sizeof(struct lttng_channel));
	43	if (chan == NULL) {
7885e399	44	PERROR("zmalloc channel init");
54d01ffb DG	45	goto error_alloc;
	46	}
	47
44d3bd01 DG	48	if (snprintf(chan->name, sizeof(chan->name), "%s",
44d3bd01 DG	49	DEFAULT_CHANNEL_NAME) < 0) {
7885e399	50	PERROR("snprintf default channel name");
54d01ffb DG	51	goto error;
	52	}
	53
0a9c6494	54	/* Same for all domains. */
54d01ffb	55	chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
0a9c6494 DG	56	chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
0a9c6494 DG	57	chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
54d01ffb DG	58
54d01ffb DG	59	switch (dom) {
1b1c65fa	60	case LTTNG_DOMAIN_KERNEL:
0a9c6494	61	assert(type == LTTNG_BUFFER_GLOBAL);
3e230f92 SM	62	chan->attr.subbuf_size =
3e230f92 SM	63	default_get_kernel_channel_subbuf_size();
1b1c65fa MD	64	chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
1b1c65fa MD	65	chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
6bb9e85f MD	66	chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
6bb9e85f MD	67	chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
1b1c65fa MD	68	break;
1b1c65fa MD	69	case LTTNG_DOMAIN_UST:
0a9c6494 DG	70	switch (type) {
	71	case LTTNG_BUFFER_PER_UID:
	72	chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
	73	chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
	74	chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
	75	chan->attr.switch_timer_interval =
	76	DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
	77	chan->attr.read_timer_interval =
	78	DEFAULT_UST_UID_CHANNEL_READ_TIMER;
	79	break;
	80	case LTTNG_BUFFER_PER_PID:
	81	default:
	82	chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
	83	chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
	84	chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
	85	chan->attr.switch_timer_interval =
	86	DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
	87	chan->attr.read_timer_interval =
	88	DEFAULT_UST_PID_CHANNEL_READ_TIMER;
	89	break;
	90	}
1b1c65fa MD	91	break;
	92	default:
	93	goto error; /* Not implemented */
54d01ffb DG	94	}
	95
	96	return chan;
	97
	98	error:
	99	free(chan);
	100	error_alloc:
	101	return NULL;
	102	}
	103
	104	/*
	105	* Disable kernel channel of the kernel session.
	106	*/
	107	int channel_kernel_disable(struct ltt_kernel_session *ksession,
	108	char *channel_name)
	109	{
	110	int ret;
	111	struct ltt_kernel_channel *kchan;
	112
0525e9ae DG	113	assert(ksession);
	114	assert(channel_name);
	115
54d01ffb DG	116	kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
54d01ffb DG	117	if (kchan == NULL) {
f73fabfd	118	ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
54d01ffb	119	goto error;
0525e9ae DG	120	}
	121
	122	/* Only if channel is enabled disable it. */
	123	if (kchan->enabled == 1) {
54d01ffb	124	ret = kernel_disable_channel(kchan);
7885e399	125	if (ret < 0 && ret != -EEXIST) {
f73fabfd	126	ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
54d01ffb DG	127	goto error;
	128	}
	129	}
	130
f73fabfd	131	ret = LTTNG_OK;
54d01ffb DG	132
	133	error:
	134	return ret;
	135	}
	136
	137	/*
	138	* Enable kernel channel of the kernel session.
	139	*/
	140	int channel_kernel_enable(struct ltt_kernel_session *ksession,
	141	struct ltt_kernel_channel *kchan)
	142	{
	143	int ret;
	144
0525e9ae DG	145	assert(ksession);
	146	assert(kchan);
	147
54d01ffb DG	148	if (kchan->enabled == 0) {
	149	ret = kernel_enable_channel(kchan);
	150	if (ret < 0) {
f73fabfd	151	ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
54d01ffb DG	152	goto error;
54d01ffb DG	153	}
42224349	154	} else {
f73fabfd	155	ret = LTTNG_ERR_KERN_CHAN_EXIST;
42224349	156	goto error;
54d01ffb DG	157	}
54d01ffb DG	158
f73fabfd	159	ret = LTTNG_OK;
54d01ffb DG	160
	161	error:
	162	return ret;
	163	}
	164
	165	/*
	166	* Create kernel channel of the kernel session and notify kernel thread.
	167	*/
	168	int channel_kernel_create(struct ltt_kernel_session *ksession,
ff4d74e6	169	struct lttng_channel *attr, int kernel_pipe)
54d01ffb DG	170	{
54d01ffb DG	171	int ret;
ff4d74e6	172	struct lttng_channel *defattr = NULL;
54d01ffb	173
0525e9ae DG	174	assert(ksession);
0525e9ae DG	175
54d01ffb DG	176	/* Creating channel attributes if needed */
54d01ffb DG	177	if (attr == NULL) {
0a9c6494 DG	178	defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
0a9c6494 DG	179	LTTNG_BUFFER_GLOBAL);
ff4d74e6	180	if (defattr == NULL) {
f73fabfd	181	ret = LTTNG_ERR_FATAL;
54d01ffb DG	182	goto error;
54d01ffb DG	183	}
ff4d74e6	184	attr = defattr;
54d01ffb DG	185	}
54d01ffb DG	186
27babd3a DG	187	if (ksession->snapshot_mode) {
	188	/* Force channel attribute for snapshot mode. */
	189	attr->attr.overwrite = 1;
	190	attr->attr.output = LTTNG_EVENT_MMAP;
	191	}
	192
54d01ffb	193	/* Channel not found, creating it */
fdd9eb17	194	ret = kernel_create_channel(ksession, attr);
54d01ffb	195	if (ret < 0) {
f73fabfd	196	ret = LTTNG_ERR_KERN_CHAN_FAIL;
54d01ffb DG	197	goto error;
	198	}
	199
	200	/* Notify kernel thread that there is a new channel */
	201	ret = notify_thread_pipe(kernel_pipe);
	202	if (ret < 0) {
f73fabfd	203	ret = LTTNG_ERR_FATAL;
54d01ffb DG	204	goto error;
	205	}
	206
f73fabfd	207	ret = LTTNG_OK;
54d01ffb	208	error:
ff4d74e6	209	free(defattr);
54d01ffb DG	210	return ret;
54d01ffb DG	211	}
7885e399 DG	212
	213	/*
	214	* Enable UST channel for session and domain.
	215	*/
7972aab2	216	int channel_ust_enable(struct ltt_ust_session *usess,
7885e399 DG	217	struct ltt_ust_channel *uchan)
7885e399 DG	218	{
f73fabfd	219	int ret = LTTNG_OK;
7885e399	220
0525e9ae DG	221	assert(usess);
	222	assert(uchan);
	223
7885e399 DG	224	/* If already enabled, everything is OK */
	225	if (uchan->enabled) {
	226	DBG3("Channel %s already enabled. Skipping", uchan->name);
f73fabfd	227	ret = LTTNG_ERR_UST_CHAN_EXIST;
7885e399 DG	228	goto end;
	229	}
	230
7972aab2 DG	231	DBG2("Channel %s being enabled in UST domain", uchan->name);
	232
	233	/*
	234	* Enable channel for UST global domain on all applications. Ignore return
	235	* value here since whatever error we got, it means that the channel was
	236	* not created on one or many registered applications and we can not report
	237	* this to the user yet. However, at this stage, the channel was
	238	* successfully created on the session daemon side so the enable-channel
	239	* command is a success.
	240	*/
d54b4440	241	(void) ust_app_enable_channel_glb(usess, uchan);
7885e399	242
7885e399 DG	243	uchan->enabled = 1;
	244	DBG2("Channel %s enabled successfully", uchan->name);
	245
	246	end:
7885e399 DG	247	return ret;
	248	}
	249
	250	/*
	251	* Create UST channel for session and domain.
	252	*/
7972aab2 DG	253	int channel_ust_create(struct ltt_ust_session *usess,
7972aab2 DG	254	struct lttng_channel *attr, enum lttng_buffer_type type)
7885e399	255	{
f73fabfd	256	int ret = LTTNG_OK;
7885e399 DG	257	struct ltt_ust_channel *uchan = NULL;
	258	struct lttng_channel *defattr = NULL;
	259
0525e9ae DG	260	assert(usess);
0525e9ae DG	261
7885e399 DG	262	/* Creating channel attributes if needed */
7885e399 DG	263	if (attr == NULL) {
0a9c6494	264	defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
7885e399	265	if (defattr == NULL) {
f73fabfd	266	ret = LTTNG_ERR_FATAL;
7885e399 DG	267	goto error;
	268	}
	269	attr = defattr;
	270	}
	271
27babd3a DG	272	if (usess->snapshot_mode) {
	273	/* Force channel attribute for snapshot mode. */
	274	attr->attr.overwrite = 1;
	275	attr->attr.output = LTTNG_EVENT_MMAP;
	276	}
	277
b024d072	278	/*
0525e9ae DG	279	* Validate UST buffer size and number of buffers: must both be power of 2
	280	* and nonzero. We validate right here for UST, because applications will
	281	* not report the error to the user (unlike kernel tracing).
b024d072	282	*/
0525e9ae DG	283	if (!attr->attr.subbuf_size \|\|
0525e9ae DG	284	(attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
f73fabfd	285	ret = LTTNG_ERR_INVALID;
b024d072 MD	286	goto error;
b024d072 MD	287	}
0525e9ae	288
12744796 DG	289	/*
	290	* Invalid subbuffer size if it's lower then the page size.
	291	*/
	292	if (attr->attr.subbuf_size < page_size) {
	293	ret = LTTNG_ERR_INVALID;
	294	goto error;
	295	}
	296
0525e9ae DG	297	if (!attr->attr.num_subbuf \|\|
0525e9ae DG	298	(attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
f73fabfd	299	ret = LTTNG_ERR_INVALID;
b024d072 MD	300	goto error;
	301	}
	302
a79d84dd DG	303	if (attr->attr.output != LTTNG_EVENT_MMAP) {
	304	ret = LTTNG_ERR_NOT_SUPPORTED;
	305	goto error;
	306	}
	307
1624d5b7 JD	308	/*
	309	* The tracefile_size should not be < to the subbuf_size, otherwise
	310	* we won't be able to write the packets on disk
	311	*/
	312	if ((attr->attr.tracefile_size > 0) &&
	313	(attr->attr.tracefile_size < attr->attr.subbuf_size)) {
	314	ret = LTTNG_ERR_INVALID;
	315	goto error;
	316	}
	317
2e8269f7 DG	318	/* Validate buffer type. */
	319	switch (type) {
	320	case LTTNG_BUFFER_PER_PID:
0a9c6494	321	break;
2e8269f7 DG	322	case LTTNG_BUFFER_PER_UID:
	323	break;
	324	default:
	325	ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
	326	goto error;
	327	}
	328
7885e399	329	/* Create UST channel */
dec56f6c	330	uchan = trace_ust_create_channel(attr);
7885e399	331	if (uchan == NULL) {
f73fabfd	332	ret = LTTNG_ERR_FATAL;
7885e399 DG	333	goto error;
7885e399 DG	334	}
58f3ca76	335	uchan->enabled = 1;
7972aab2 DG	336	if (trace_ust_is_max_id(usess->used_channel_id)) {
	337	ret = LTTNG_ERR_UST_CHAN_FAIL;
	338	goto error;
	339	}
	340	uchan->id = trace_ust_get_next_chan_id(usess);
	341
	342	DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
	343	uchan->name, type, uchan->id);
	344
	345	/* Flag session buffer type. */
	346	if (!usess->buffer_type_changed) {
	347	usess->buffer_type = type;
	348	usess->buffer_type_changed = 1;
	349	} else if (usess->buffer_type != type) {
	350	/* Buffer type was already set. Refuse to create channel. */
	351	ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
7885e399 DG	352	goto error_free_chan;
	353	}
	354
7972aab2 DG	355	/* Enable channel for global domain */
7972aab2 DG	356	ret = ust_app_create_channel_glb(usess, uchan);
49c336c1	357	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
f73fabfd	358	ret = LTTNG_ERR_UST_CHAN_FAIL;
7885e399 DG	359	goto error_free_chan;
	360	}
	361
fc34caaa DG	362	/* Adding the channel to the channel hash table. */
	363	rcu_read_lock();
	364	lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
	365	rcu_read_unlock();
	366
7885e399 DG	367	DBG2("Channel %s created successfully", uchan->name);
	368
	369	free(defattr);
f73fabfd	370	return LTTNG_OK;
7885e399 DG	371
7885e399 DG	372	error_free_chan:
24d1723f DG	373	/*
	374	* No need to remove the channel from the hash table because at this point
	375	* it was not added hence the direct call and no call_rcu().
	376	*/
7885e399 DG	377	trace_ust_destroy_channel(uchan);
	378	error:
	379	free(defattr);
	380	return ret;
	381	}
	382
	383	/*
	384	* Disable UST channel for session and domain.
	385	*/
7972aab2	386	int channel_ust_disable(struct ltt_ust_session *usess,
7885e399 DG	387	struct ltt_ust_channel *uchan)
7885e399 DG	388	{
f73fabfd	389	int ret = LTTNG_OK;
7885e399	390
0525e9ae DG	391	assert(usess);
	392	assert(uchan);
	393
7885e399 DG	394	/* Already disabled */
	395	if (uchan->enabled == 0) {
	396	DBG2("Channel UST %s already disabled", uchan->name);
	397	goto end;
	398	}
	399
7972aab2 DG	400	DBG2("Channel %s being disabled in UST global domain", uchan->name);
	401	/* Disable channel for global domain */
	402	ret = ust_app_disable_channel_glb(usess, uchan);
49c336c1	403	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
f73fabfd	404	ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
7885e399 DG	405	goto error;
	406	}
	407
	408	uchan->enabled = 0;
	409
	410	DBG2("Channel %s disabled successfully", uchan->name);
	411
f73fabfd	412	return LTTNG_OK;
7885e399 DG	413
	414	end:
	415	error:
	416	return ret;
	417	}