[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"

/*
 * 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;

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

	/* 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;
		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;
			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_UID_CHANNEL_LIVE_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(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, LTTNG_DOMAIN_UST);
	if (uchan == NULL) {
		ret = LTTNG_ERR_FATAL;
		goto error;
	}

	/*
	 * HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
	 * based on the default name.
	 */
	if (!strcmp(uchan->name, DEFAULT_JUL_CHANNEL_NAME)) {
		uchan->domain = LTTNG_DOMAIN_JUL;
	} else if (!strcmp(uchan->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
		uchan->domain = LTTNG_DOMAIN_LOG4J;
	} else if (!strcmp(uchan->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
		uchan->domain = LTTNG_DOMAIN_PYTHON;
	}

	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);

	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	/*
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"
54d01ffb DG	34
	35	/*
	36	* Return allocated channel attributes.
	37	*/
0a9c6494 DG	38	struct lttng_channel *channel_new_default_attr(int dom,
0a9c6494 DG	39	enum lttng_buffer_type type)
54d01ffb DG	40	{
54d01ffb DG	41	struct lttng_channel *chan;
bdf64013	42	const char *channel_name = DEFAULT_CHANNEL_NAME;
54d01ffb DG	43
	44	chan = zmalloc(sizeof(struct lttng_channel));
	45	if (chan == NULL) {
7885e399	46	PERROR("zmalloc channel init");
54d01ffb DG	47	goto error_alloc;
	48	}
	49
0a9c6494	50	/* Same for all domains. */
54d01ffb	51	chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
0a9c6494 DG	52	chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
0a9c6494 DG	53	chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
54d01ffb DG	54
54d01ffb DG	55	switch (dom) {
1b1c65fa	56	case LTTNG_DOMAIN_KERNEL:
0a9c6494	57	assert(type == LTTNG_BUFFER_GLOBAL);
3e230f92 SM	58	chan->attr.subbuf_size =
3e230f92 SM	59	default_get_kernel_channel_subbuf_size();
1b1c65fa MD	60	chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
1b1c65fa MD	61	chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
6bb9e85f MD	62	chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
6bb9e85f MD	63	chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
ecc48a90	64	chan->attr.live_timer_interval = DEFAULT_KERNEL_CHANNEL_LIVE_TIMER;
1b1c65fa	65	break;
bdf64013 JG	66	case LTTNG_DOMAIN_JUL:
	67	channel_name = DEFAULT_JUL_CHANNEL_NAME;
	68	goto common_ust;
	69	case LTTNG_DOMAIN_LOG4J:
	70	channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
	71	goto common_ust;
	72	case LTTNG_DOMAIN_PYTHON:
	73	channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
	74	goto common_ust;
1b1c65fa	75	case LTTNG_DOMAIN_UST:
bdf64013	76	common_ust:
0a9c6494 DG	77	switch (type) {
	78	case LTTNG_BUFFER_PER_UID:
	79	chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
	80	chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
	81	chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
	82	chan->attr.switch_timer_interval =
	83	DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
	84	chan->attr.read_timer_interval =
	85	DEFAULT_UST_UID_CHANNEL_READ_TIMER;
ecc48a90 JD	86	chan->attr.live_timer_interval =
ecc48a90 JD	87	DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
0a9c6494 DG	88	break;
	89	case LTTNG_BUFFER_PER_PID:
	90	default:
	91	chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
	92	chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
	93	chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
	94	chan->attr.switch_timer_interval =
	95	DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
	96	chan->attr.read_timer_interval =
	97	DEFAULT_UST_PID_CHANNEL_READ_TIMER;
ecc48a90 JD	98	chan->attr.live_timer_interval =
ecc48a90 JD	99	DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
0a9c6494 DG	100	break;
0a9c6494 DG	101	}
1b1c65fa MD	102	break;
	103	default:
	104	goto error; /* Not implemented */
54d01ffb DG	105	}
54d01ffb DG	106
bdf64013 JG	107	if (snprintf(chan->name, sizeof(chan->name), "%s",
	108	channel_name) < 0) {
	109	PERROR("snprintf default channel name");
	110	goto error;
	111	}
54d01ffb DG	112	return chan;
	113
	114	error:
	115	free(chan);
	116	error_alloc:
	117	return NULL;
	118	}
	119
	120	/*
	121	* Disable kernel channel of the kernel session.
	122	*/
	123	int channel_kernel_disable(struct ltt_kernel_session *ksession,
	124	char *channel_name)
	125	{
	126	int ret;
	127	struct ltt_kernel_channel *kchan;
	128
0525e9ae DG	129	assert(ksession);
	130	assert(channel_name);
	131
54d01ffb DG	132	kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
54d01ffb DG	133	if (kchan == NULL) {
f73fabfd	134	ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
54d01ffb	135	goto error;
0525e9ae DG	136	}
	137
	138	/* Only if channel is enabled disable it. */
	139	if (kchan->enabled == 1) {
54d01ffb	140	ret = kernel_disable_channel(kchan);
7885e399	141	if (ret < 0 && ret != -EEXIST) {
f73fabfd	142	ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
54d01ffb DG	143	goto error;
	144	}
	145	}
	146
f73fabfd	147	ret = LTTNG_OK;
54d01ffb DG	148
	149	error:
	150	return ret;
	151	}
	152
	153	/*
	154	* Enable kernel channel of the kernel session.
	155	*/
	156	int channel_kernel_enable(struct ltt_kernel_session *ksession,
	157	struct ltt_kernel_channel *kchan)
	158	{
	159	int ret;
	160
0525e9ae DG	161	assert(ksession);
	162	assert(kchan);
	163
54d01ffb DG	164	if (kchan->enabled == 0) {
	165	ret = kernel_enable_channel(kchan);
	166	if (ret < 0) {
f73fabfd	167	ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
54d01ffb DG	168	goto error;
54d01ffb DG	169	}
42224349	170	} else {
f73fabfd	171	ret = LTTNG_ERR_KERN_CHAN_EXIST;
42224349	172	goto error;
54d01ffb DG	173	}
54d01ffb DG	174
f73fabfd	175	ret = LTTNG_OK;
54d01ffb DG	176
	177	error:
	178	return ret;
	179	}
	180
	181	/*
	182	* Create kernel channel of the kernel session and notify kernel thread.
	183	*/
	184	int channel_kernel_create(struct ltt_kernel_session *ksession,
ff4d74e6	185	struct lttng_channel *attr, int kernel_pipe)
54d01ffb DG	186	{
54d01ffb DG	187	int ret;
ff4d74e6	188	struct lttng_channel *defattr = NULL;
54d01ffb	189
0525e9ae DG	190	assert(ksession);
0525e9ae DG	191
54d01ffb DG	192	/* Creating channel attributes if needed */
54d01ffb DG	193	if (attr == NULL) {
0a9c6494 DG	194	defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
0a9c6494 DG	195	LTTNG_BUFFER_GLOBAL);
ff4d74e6	196	if (defattr == NULL) {
f73fabfd	197	ret = LTTNG_ERR_FATAL;
54d01ffb DG	198	goto error;
54d01ffb DG	199	}
ff4d74e6	200	attr = defattr;
54d01ffb DG	201	}
54d01ffb DG	202
27babd3a DG	203	if (ksession->snapshot_mode) {
	204	/* Force channel attribute for snapshot mode. */
	205	attr->attr.overwrite = 1;
	206	attr->attr.output = LTTNG_EVENT_MMAP;
	207	}
	208
54d01ffb	209	/* Channel not found, creating it */
fdd9eb17	210	ret = kernel_create_channel(ksession, attr);
54d01ffb	211	if (ret < 0) {
f73fabfd	212	ret = LTTNG_ERR_KERN_CHAN_FAIL;
54d01ffb DG	213	goto error;
	214	}
	215
	216	/* Notify kernel thread that there is a new channel */
	217	ret = notify_thread_pipe(kernel_pipe);
	218	if (ret < 0) {
f73fabfd	219	ret = LTTNG_ERR_FATAL;
54d01ffb DG	220	goto error;
	221	}
	222
f73fabfd	223	ret = LTTNG_OK;
54d01ffb	224	error:
ff4d74e6	225	free(defattr);
54d01ffb DG	226	return ret;
54d01ffb DG	227	}
7885e399 DG	228
	229	/*
	230	* Enable UST channel for session and domain.
	231	*/
7972aab2	232	int channel_ust_enable(struct ltt_ust_session *usess,
7885e399 DG	233	struct ltt_ust_channel *uchan)
7885e399 DG	234	{
f73fabfd	235	int ret = LTTNG_OK;
7885e399	236
0525e9ae DG	237	assert(usess);
	238	assert(uchan);
	239
7885e399 DG	240	/* If already enabled, everything is OK */
	241	if (uchan->enabled) {
	242	DBG3("Channel %s already enabled. Skipping", uchan->name);
f73fabfd	243	ret = LTTNG_ERR_UST_CHAN_EXIST;
7885e399 DG	244	goto end;
	245	}
	246
7972aab2 DG	247	DBG2("Channel %s being enabled in UST domain", uchan->name);
	248
	249	/*
	250	* Enable channel for UST global domain on all applications. Ignore return
	251	* value here since whatever error we got, it means that the channel was
	252	* not created on one or many registered applications and we can not report
	253	* this to the user yet. However, at this stage, the channel was
	254	* successfully created on the session daemon side so the enable-channel
	255	* command is a success.
	256	*/
d54b4440	257	(void) ust_app_enable_channel_glb(usess, uchan);
7885e399	258
7885e399 DG	259	uchan->enabled = 1;
	260	DBG2("Channel %s enabled successfully", uchan->name);
	261
	262	end:
7885e399 DG	263	return ret;
	264	}
	265
	266	/*
	267	* Create UST channel for session and domain.
	268	*/
7972aab2 DG	269	int channel_ust_create(struct ltt_ust_session *usess,
7972aab2 DG	270	struct lttng_channel *attr, enum lttng_buffer_type type)
7885e399	271	{
f73fabfd	272	int ret = LTTNG_OK;
7885e399 DG	273	struct ltt_ust_channel *uchan = NULL;
	274	struct lttng_channel *defattr = NULL;
	275
0525e9ae DG	276	assert(usess);
0525e9ae DG	277
7885e399 DG	278	/* Creating channel attributes if needed */
7885e399 DG	279	if (attr == NULL) {
0a9c6494	280	defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
7885e399	281	if (defattr == NULL) {
f73fabfd	282	ret = LTTNG_ERR_FATAL;
7885e399 DG	283	goto error;
	284	}
	285	attr = defattr;
	286	}
	287
27babd3a DG	288	if (usess->snapshot_mode) {
	289	/* Force channel attribute for snapshot mode. */
	290	attr->attr.overwrite = 1;
	291	attr->attr.output = LTTNG_EVENT_MMAP;
	292	}
	293
b024d072	294	/*
0525e9ae DG	295	* Validate UST buffer size and number of buffers: must both be power of 2
	296	* and nonzero. We validate right here for UST, because applications will
	297	* not report the error to the user (unlike kernel tracing).
b024d072	298	*/
0525e9ae DG	299	if (!attr->attr.subbuf_size \|\|
0525e9ae DG	300	(attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
f73fabfd	301	ret = LTTNG_ERR_INVALID;
b024d072 MD	302	goto error;
b024d072 MD	303	}
0525e9ae	304
12744796 DG	305	/*
	306	* Invalid subbuffer size if it's lower then the page size.
	307	*/
	308	if (attr->attr.subbuf_size < page_size) {
	309	ret = LTTNG_ERR_INVALID;
	310	goto error;
	311	}
	312
0525e9ae DG	313	if (!attr->attr.num_subbuf \|\|
0525e9ae DG	314	(attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
f73fabfd	315	ret = LTTNG_ERR_INVALID;
b024d072 MD	316	goto error;
	317	}
	318
a79d84dd DG	319	if (attr->attr.output != LTTNG_EVENT_MMAP) {
	320	ret = LTTNG_ERR_NOT_SUPPORTED;
	321	goto error;
	322	}
	323
1624d5b7 JD	324	/*
	325	* The tracefile_size should not be < to the subbuf_size, otherwise
	326	* we won't be able to write the packets on disk
	327	*/
	328	if ((attr->attr.tracefile_size > 0) &&
	329	(attr->attr.tracefile_size < attr->attr.subbuf_size)) {
	330	ret = LTTNG_ERR_INVALID;
	331	goto error;
	332	}
	333
2e8269f7 DG	334	/* Validate buffer type. */
	335	switch (type) {
	336	case LTTNG_BUFFER_PER_PID:
0a9c6494	337	break;
2e8269f7 DG	338	case LTTNG_BUFFER_PER_UID:
	339	break;
	340	default:
	341	ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
	342	goto error;
	343	}
	344
7885e399	345	/* Create UST channel */
51755dc8	346	uchan = trace_ust_create_channel(attr, LTTNG_DOMAIN_UST);
7885e399	347	if (uchan == NULL) {
f73fabfd	348	ret = LTTNG_ERR_FATAL;
7885e399 DG	349	goto error;
7885e399 DG	350	}
51755dc8 JG	351
	352	/*
	353	* HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
	354	* based on the default name.
	355	*/
	356	if (!strcmp(uchan->name, DEFAULT_JUL_CHANNEL_NAME)) {
	357	uchan->domain = LTTNG_DOMAIN_JUL;
	358	} else if (!strcmp(uchan->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
	359	uchan->domain = LTTNG_DOMAIN_LOG4J;
	360	} else if (!strcmp(uchan->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
	361	uchan->domain = LTTNG_DOMAIN_PYTHON;
	362	}
	363
58f3ca76	364	uchan->enabled = 1;
7972aab2 DG	365	if (trace_ust_is_max_id(usess->used_channel_id)) {
	366	ret = LTTNG_ERR_UST_CHAN_FAIL;
	367	goto error;
	368	}
	369	uchan->id = trace_ust_get_next_chan_id(usess);
	370
	371	DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
	372	uchan->name, type, uchan->id);
	373
	374	/* Flag session buffer type. */
	375	if (!usess->buffer_type_changed) {
	376	usess->buffer_type = type;
	377	usess->buffer_type_changed = 1;
	378	} else if (usess->buffer_type != type) {
	379	/* Buffer type was already set. Refuse to create channel. */
	380	ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
7885e399 DG	381	goto error_free_chan;
	382	}
	383
7972aab2 DG	384	/* Enable channel for global domain */
7972aab2 DG	385	ret = ust_app_create_channel_glb(usess, uchan);
49c336c1	386	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
f73fabfd	387	ret = LTTNG_ERR_UST_CHAN_FAIL;
7885e399 DG	388	goto error_free_chan;
	389	}
	390
fc34caaa DG	391	/* Adding the channel to the channel hash table. */
fc34caaa DG	392	rcu_read_lock();
ad7a9107 DG	393	if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
	394	sizeof(uchan->name))) {
	395	lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
84ad93e8 DG	396	} else {
	397	/*
	398	* Copy channel attribute to session if this is metadata so if NO
	399	* application exists we can access that data in the shadow copy during
	400	* the global update of newly registered application.
	401	*/
	402	memcpy(&usess->metadata_attr, &uchan->attr,
	403	sizeof(usess->metadata_attr));
ad7a9107	404	}
fc34caaa DG	405	rcu_read_unlock();
fc34caaa DG	406
7885e399 DG	407	DBG2("Channel %s created successfully", uchan->name);
	408
	409	free(defattr);
f73fabfd	410	return LTTNG_OK;
7885e399 DG	411
7885e399 DG	412	error_free_chan:
24d1723f DG	413	/*
	414	* No need to remove the channel from the hash table because at this point
	415	* it was not added hence the direct call and no call_rcu().
	416	*/
7885e399 DG	417	trace_ust_destroy_channel(uchan);
	418	error:
	419	free(defattr);
	420	return ret;
	421	}
	422
	423	/*
	424	* Disable UST channel for session and domain.
	425	*/
7972aab2	426	int channel_ust_disable(struct ltt_ust_session *usess,
7885e399 DG	427	struct ltt_ust_channel *uchan)
7885e399 DG	428	{
f73fabfd	429	int ret = LTTNG_OK;
7885e399	430
0525e9ae DG	431	assert(usess);
	432	assert(uchan);
	433
7885e399 DG	434	/* Already disabled */
	435	if (uchan->enabled == 0) {
	436	DBG2("Channel UST %s already disabled", uchan->name);
	437	goto end;
	438	}
	439
7972aab2 DG	440	DBG2("Channel %s being disabled in UST global domain", uchan->name);
	441	/* Disable channel for global domain */
	442	ret = ust_app_disable_channel_glb(usess, uchan);
49c336c1	443	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
f73fabfd	444	ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
7885e399 DG	445	goto error;
	446	}
	447
	448	uchan->enabled = 0;
	449
	450	DBG2("Channel %s disabled successfully", uchan->name);
	451
f73fabfd	452	return LTTNG_OK;
7885e399 DG	453
	454	end:
	455	error:
	456	return ret;
	457	}