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

/*
 * Copyright (C) 2011 EfficiOS Inc.
 * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#define _LGPL_SOURCE
#include "agent.hpp"
#include "channel.hpp"
#include "kernel.hpp"
#include "lttng-sessiond.hpp"
#include "lttng-ust-ctl.hpp"
#include "lttng-ust-error.hpp"
#include "ust-app.hpp"
#include "utils.hpp"

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

#include <inttypes.h>
#include <string.h>
#include <unistd.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 = nullptr;

	chan = zmalloc<lttng_channel>();
	if (chan == nullptr) {
		PERROR("zmalloc channel init");
		goto error_alloc;
	}

	extended_attr = zmalloc<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:
		LTTNG_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 nullptr;
}

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;

	LTTNG_ASSERT(ksession);
	LTTNG_ASSERT(channel_name);

	kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
	if (kchan == nullptr) {
		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.
 */
enum lttng_error_code channel_kernel_enable(struct ltt_kernel_session *ksession,
					    struct ltt_kernel_channel *kchan)
{
	enum lttng_error_code ret_code;

	LTTNG_ASSERT(ksession);
	LTTNG_ASSERT(kchan);

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

	ret_code = LTTNG_OK;

error:
	return ret_code;
}

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.
 */
enum lttng_error_code channel_kernel_create(struct ltt_kernel_session *ksession,
					    struct lttng_channel *attr,
					    int kernel_pipe)
{
	enum lttng_error_code ret_code;
	struct lttng_channel *defattr = nullptr;

	LTTNG_ASSERT(ksession);

	/* Creating channel attributes if needed */
	if (attr == nullptr) {
		defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL, LTTNG_BUFFER_GLOBAL);
		if (defattr == nullptr) {
			ret_code = 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;
	}

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

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

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

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

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

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

	LTTNG_ASSERT(usess);
	LTTNG_ASSERT(uchan);

	/* If already enabled, everything is OK */
	if (uchan->enabled) {
		DBG3("Channel %s already enabled. Skipping", uchan->name);
		ret_code = LTTNG_ERR_UST_CHAN_EXIST;
		goto end;
	} else {
		uchan->enabled = 1;
		DBG2("Channel %s enabled successfully", uchan->name);
	}

	if (!usess->active) {
		/*
		 * The channel will be activated against the apps
		 * when the session is started as part of the
		 * application channel "synchronize" operation.
		 */
		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);

end:
	return ret_code;
}

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

	LTTNG_ASSERT(usess);

	/* Creating channel attributes if needed */
	if (attr == nullptr) {
		defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
		if (defattr == nullptr) {
			ret_code = 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_code = 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_code = LTTNG_ERR_INVALID;
		goto error;
	}

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

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

	if (attr->attr.output != LTTNG_EVENT_MMAP) {
		ret_code = 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_code = LTTNG_ERR_INVALID;
		goto error;
	}

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

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

	uchan->enabled = 1;
	if (trace_ust_is_max_id(usess->used_channel_id)) {
		ret_code = 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_code = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
		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)) != 0) {
		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_code = 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_code;
}

/*
 * 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;

	LTTNG_ASSERT(usess);
	LTTNG_ASSERT(uchan);

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

	uchan->enabled = 0;

	/*
	 * If session is inactive we don't notify the tracer right away. We
	 * wait for the next synchronization.
	 */
	if (!usess->active) {
		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;
	}

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

	return LTTNG_OK;

end:
error:
	return ret;
}

struct lttng_channel *trace_ust_channel_to_lttng_channel(const struct ltt_ust_channel *uchan)
{
	struct lttng_channel *channel = nullptr, *ret = nullptr;

	channel = lttng_channel_create_internal();
	if (!channel) {
		ERR("Failed to create lttng_channel during conversion from ltt_ust_channel to lttng_channel");
		goto end;
	}

	if (lttng_strncpy(channel->name, uchan->name, LTTNG_SYMBOL_NAME_LEN)) {
		ERR("Failed to set channel name during conversion from ltt_ust_channel to lttng_channel");
		goto end;
	}

	channel->attr.overwrite = uchan->attr.overwrite;
	channel->attr.subbuf_size = uchan->attr.subbuf_size;
	channel->attr.num_subbuf = uchan->attr.num_subbuf;
	channel->attr.switch_timer_interval = uchan->attr.switch_timer_interval;
	channel->attr.read_timer_interval = uchan->attr.read_timer_interval;
	channel->enabled = uchan->enabled;
	channel->attr.tracefile_size = uchan->tracefile_size;
	channel->attr.tracefile_count = uchan->tracefile_count;

	/*
	 * Map enum lttng_ust_output to enum lttng_event_output.
	 */
	switch (uchan->attr.output) {
	case LTTNG_UST_ABI_MMAP:
		channel->attr.output = LTTNG_EVENT_MMAP;
		break;
	default:
		/*
		 * LTTNG_UST_MMAP is the only supported UST
		 * output mode.
		 */
		abort();
		break;
	}

	lttng_channel_set_blocking_timeout(channel, uchan->attr.u.s.blocking_timeout);
	lttng_channel_set_monitor_timer_interval(channel, uchan->monitor_timer_interval);

	ret = channel;
	channel = nullptr;

end:
	lttng_channel_destroy(channel);
	return ret;
}
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2011 EfficiOS Inc.
	3	* Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
	4	*
	5	* SPDX-License-Identifier: GPL-2.0-only
	6	*
	7	*/
	8
	9	#define _LGPL_SOURCE
	10	#include "agent.hpp"
	11	#include "channel.hpp"
	12	#include "kernel.hpp"
	13	#include "lttng-sessiond.hpp"
	14	#include "lttng-ust-ctl.hpp"
	15	#include "lttng-ust-error.hpp"
	16	#include "ust-app.hpp"
	17	#include "utils.hpp"
	18
	19	#include <common/common.hpp>
	20	#include <common/defaults.hpp>
	21	#include <common/sessiond-comm/sessiond-comm.hpp>
	22
	23	#include <inttypes.h>
	24	#include <string.h>
	25	#include <unistd.h>
	26
	27	/*
	28	* Return allocated channel attributes.
	29	*/
	30	struct lttng_channel *channel_new_default_attr(int dom, enum lttng_buffer_type type)
	31	{
	32	struct lttng_channel *chan;
	33	const char *channel_name = DEFAULT_CHANNEL_NAME;
	34	struct lttng_channel_extended *extended_attr = nullptr;
	35
	36	chan = zmalloc<lttng_channel>();
	37	if (chan == nullptr) {
	38	PERROR("zmalloc channel init");
	39	goto error_alloc;
	40	}
	41
	42	extended_attr = zmalloc<lttng_channel_extended>();
	43	if (!extended_attr) {
	44	PERROR("zmalloc channel extended init");
	45	goto error;
	46	}
	47
	48	chan->attr.extended.ptr = extended_attr;
	49
	50	/* Same for all domains. */
	51	chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
	52	chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
	53	chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
	54
	55	switch (dom) {
	56	case LTTNG_DOMAIN_KERNEL:
	57	LTTNG_ASSERT(type == LTTNG_BUFFER_GLOBAL);
	58	chan->attr.subbuf_size = default_get_kernel_channel_subbuf_size();
	59	chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
	60	chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
	61	chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
	62	chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
	63	chan->attr.live_timer_interval = DEFAULT_KERNEL_CHANNEL_LIVE_TIMER;
	64	extended_attr->blocking_timeout = DEFAULT_KERNEL_CHANNEL_BLOCKING_TIMEOUT;
	65	extended_attr->monitor_timer_interval = DEFAULT_KERNEL_CHANNEL_MONITOR_TIMER;
	66	break;
	67	case LTTNG_DOMAIN_JUL:
	68	channel_name = DEFAULT_JUL_CHANNEL_NAME;
	69	goto common_ust;
	70	case LTTNG_DOMAIN_LOG4J:
	71	channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
	72	goto common_ust;
	73	case LTTNG_DOMAIN_PYTHON:
	74	channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
	75	goto common_ust;
	76	case LTTNG_DOMAIN_UST:
	77	common_ust:
	78	switch (type) {
	79	case LTTNG_BUFFER_PER_UID:
	80	chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
	81	chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
	82	chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
	83	chan->attr.switch_timer_interval = DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
	84	chan->attr.read_timer_interval = DEFAULT_UST_UID_CHANNEL_READ_TIMER;
	85	chan->attr.live_timer_interval = DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
	86	extended_attr->blocking_timeout = DEFAULT_UST_UID_CHANNEL_BLOCKING_TIMEOUT;
	87	extended_attr->monitor_timer_interval =
	88	DEFAULT_UST_UID_CHANNEL_MONITOR_TIMER;
	89	break;
	90	case LTTNG_BUFFER_PER_PID:
	91	default:
	92	chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
	93	chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
	94	chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
	95	chan->attr.switch_timer_interval = DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
	96	chan->attr.read_timer_interval = DEFAULT_UST_PID_CHANNEL_READ_TIMER;
	97	chan->attr.live_timer_interval = DEFAULT_UST_PID_CHANNEL_LIVE_TIMER;
	98	extended_attr->blocking_timeout = DEFAULT_UST_PID_CHANNEL_BLOCKING_TIMEOUT;
	99	extended_attr->monitor_timer_interval =
	100	DEFAULT_UST_PID_CHANNEL_MONITOR_TIMER;
	101	break;
	102	}
	103	break;
	104	default:
	105	goto error; /* Not implemented */
	106	}
	107
	108	if (snprintf(chan->name, sizeof(chan->name), "%s", channel_name) < 0) {
	109	PERROR("snprintf default channel name");
	110	goto error;
	111	}
	112	return chan;
	113
	114	error:
	115	free(extended_attr);
	116	free(chan);
	117	error_alloc:
	118	return nullptr;
	119	}
	120
	121	void channel_attr_destroy(struct lttng_channel *channel)
	122	{
	123	if (!channel) {
	124	return;
	125	}
	126	free(channel->attr.extended.ptr);
	127	free(channel);
	128	}
	129
	130	/*
	131	* Disable kernel channel of the kernel session.
	132	*/
	133	int channel_kernel_disable(struct ltt_kernel_session ksession, char channel_name)
	134	{
	135	int ret;
	136	struct ltt_kernel_channel *kchan;
	137
	138	LTTNG_ASSERT(ksession);
	139	LTTNG_ASSERT(channel_name);
	140
	141	kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
	142	if (kchan == nullptr) {
	143	ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
	144	goto error;
	145	}
	146
	147	/* Only if channel is enabled disable it. */
	148	if (kchan->enabled == 1) {
	149	ret = kernel_disable_channel(kchan);
	150	if (ret < 0 && ret != -EEXIST) {
	151	ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
	152	goto error;
	153	}
	154	}
	155
	156	ret = LTTNG_OK;
	157
	158	error:
	159	return ret;
	160	}
	161
	162	/*
	163	* Enable kernel channel of the kernel session.
	164	*/
	165	enum lttng_error_code channel_kernel_enable(struct ltt_kernel_session *ksession,
	166	struct ltt_kernel_channel *kchan)
	167	{
	168	enum lttng_error_code ret_code;
	169
	170	LTTNG_ASSERT(ksession);
	171	LTTNG_ASSERT(kchan);
	172
	173	if (kchan->enabled == 0) {
	174	if (kernel_enable_channel(kchan) < 0) {
	175	ret_code = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
	176	goto error;
	177	}
	178	} else {
	179	ret_code = LTTNG_ERR_KERN_CHAN_EXIST;
	180	goto error;
	181	}
	182
	183	ret_code = LTTNG_OK;
	184
	185	error:
	186	return ret_code;
	187	}
	188
	189	static int channel_validate(struct lttng_channel *attr)
	190	{
	191	/*
	192	* The ringbuffer (both in user space and kernel) behaves badly
	193	* in overwrite mode and with less than 2 subbuffers so block it
	194	* right away and send back an invalid attribute error.
	195	*/
	196	if (attr->attr.overwrite && attr->attr.num_subbuf < 2) {
	197	return -1;
	198	}
	199	return 0;
	200	}
	201
	202	static int channel_validate_kernel(struct lttng_channel *attr)
	203	{
	204	/* Kernel channels do not support blocking timeout. */
	205	if (((struct lttng_channel_extended *) attr->attr.extended.ptr)->blocking_timeout) {
	206	return -1;
	207	}
	208	return 0;
	209	}
	210
	211	/*
	212	* Create kernel channel of the kernel session and notify kernel thread.
	213	*/
	214	enum lttng_error_code channel_kernel_create(struct ltt_kernel_session *ksession,
	215	struct lttng_channel *attr,
	216	int kernel_pipe)
	217	{
	218	enum lttng_error_code ret_code;
	219	struct lttng_channel *defattr = nullptr;
	220
	221	LTTNG_ASSERT(ksession);
	222
	223	/* Creating channel attributes if needed */
	224	if (attr == nullptr) {
	225	defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL, LTTNG_BUFFER_GLOBAL);
	226	if (defattr == nullptr) {
	227	ret_code = LTTNG_ERR_FATAL;
	228	goto error;
	229	}
	230	attr = defattr;
	231	}
	232
	233	/*
	234	* Set the overwrite mode for this channel based on the session
	235	* type unless the client explicitly overrides the channel mode.
	236	*/
	237	if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
	238	attr->attr.overwrite = !!ksession->snapshot_mode;
	239	}
	240
	241	/* Validate common channel properties. */
	242	if (channel_validate(attr) < 0) {
	243	ret_code = LTTNG_ERR_INVALID;
	244	goto error;
	245	}
	246
	247	if (channel_validate_kernel(attr) < 0) {
	248	ret_code = LTTNG_ERR_INVALID;
	249	goto error;
	250	}
	251
	252	/* Channel not found, creating it. */
	253	if (kernel_create_channel(ksession, attr) < 0) {
	254	ret_code = LTTNG_ERR_KERN_CHAN_FAIL;
	255	goto error;
	256	}
	257
	258	/* Notify kernel thread that there is a new channel */
	259	if (notify_thread_pipe(kernel_pipe) < 0) {
	260	ret_code = LTTNG_ERR_FATAL;
	261	goto error;
	262	}
	263
	264	ret_code = LTTNG_OK;
	265	error:
	266	channel_attr_destroy(defattr);
	267	return ret_code;
	268	}
	269
	270	/*
	271	* Enable UST channel for session and domain.
	272	*/
	273	enum lttng_error_code channel_ust_enable(struct ltt_ust_session *usess,
	274	struct ltt_ust_channel *uchan)
	275	{
	276	enum lttng_error_code ret_code = LTTNG_OK;
	277
	278	LTTNG_ASSERT(usess);
	279	LTTNG_ASSERT(uchan);
	280
	281	/* If already enabled, everything is OK */
	282	if (uchan->enabled) {
	283	DBG3("Channel %s already enabled. Skipping", uchan->name);
	284	ret_code = LTTNG_ERR_UST_CHAN_EXIST;
	285	goto end;
	286	} else {
	287	uchan->enabled = 1;
	288	DBG2("Channel %s enabled successfully", uchan->name);
	289	}
	290
	291	if (!usess->active) {
	292	/*
	293	* The channel will be activated against the apps
	294	* when the session is started as part of the
	295	* application channel "synchronize" operation.
	296	*/
	297	goto end;
	298	}
	299
	300	DBG2("Channel %s being enabled in UST domain", uchan->name);
	301
	302	/*
	303	* Enable channel for UST global domain on all applications. Ignore return
	304	* value here since whatever error we got, it means that the channel was
	305	* not created on one or many registered applications and we can not report
	306	* this to the user yet. However, at this stage, the channel was
	307	* successfully created on the session daemon side so the enable-channel
	308	* command is a success.
	309	*/
	310	(void) ust_app_enable_channel_glb(usess, uchan);
	311
	312	end:
	313	return ret_code;
	314	}
	315
	316	/*
	317	* Create UST channel for session and domain.
	318	*/
	319	enum lttng_error_code channel_ust_create(struct ltt_ust_session *usess,
	320	struct lttng_channel *attr,
	321	enum lttng_buffer_type type)
	322	{
	323	enum lttng_error_code ret_code = LTTNG_OK;
	324	struct ltt_ust_channel *uchan = nullptr;
	325	struct lttng_channel *defattr = nullptr;
	326	enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
	327	bool chan_published = false;
	328
	329	LTTNG_ASSERT(usess);
	330
	331	/* Creating channel attributes if needed */
	332	if (attr == nullptr) {
	333	defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
	334	if (defattr == nullptr) {
	335	ret_code = LTTNG_ERR_FATAL;
	336	goto error;
	337	}
	338	attr = defattr;
	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	}
	351	}
	352
	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. */
	362	if (usess->snapshot_mode) {
	363	attr->attr.output = LTTNG_EVENT_MMAP;
	364	}
	365
	366	/* Validate common channel properties. */
	367	if (channel_validate(attr) < 0) {
	368	ret_code = LTTNG_ERR_INVALID;
	369	goto error;
	370	}
	371
	372	/*
	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).
	376	*/
	377	if (!attr->attr.subbuf_size \|\| (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
	378	ret_code = LTTNG_ERR_INVALID;
	379	goto error;
	380	}
	381
	382	/*
	383	* Invalid subbuffer size if it's lower then the page size.
	384	*/
	385	if (attr->attr.subbuf_size < the_page_size) {
	386	ret_code = LTTNG_ERR_INVALID;
	387	goto error;
	388	}
	389
	390	if (!attr->attr.num_subbuf \|\| (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
	391	ret_code = LTTNG_ERR_INVALID;
	392	goto error;
	393	}
	394
	395	if (attr->attr.output != LTTNG_EVENT_MMAP) {
	396	ret_code = LTTNG_ERR_NOT_SUPPORTED;
	397	goto error;
	398	}
	399
	400	/*
	401	* The tracefile_size should not be < to the subbuf_size, otherwise
	402	* we won't be able to write the packets on disk
	403	*/
	404	if ((attr->attr.tracefile_size > 0) &&
	405	(attr->attr.tracefile_size < attr->attr.subbuf_size)) {
	406	ret_code = LTTNG_ERR_INVALID;
	407	goto error;
	408	}
	409
	410	/* Validate buffer type. */
	411	switch (type) {
	412	case LTTNG_BUFFER_PER_PID:
	413	break;
	414	case LTTNG_BUFFER_PER_UID:
	415	break;
	416	default:
	417	ret_code = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
	418	goto error;
	419	}
	420
	421	/* Create UST channel */
	422	uchan = trace_ust_create_channel(attr, domain);
	423	if (uchan == nullptr) {
	424	ret_code = LTTNG_ERR_FATAL;
	425	goto error;
	426	}
	427
	428	uchan->enabled = 1;
	429	if (trace_ust_is_max_id(usess->used_channel_id)) {
	430	ret_code = LTTNG_ERR_UST_CHAN_FAIL;
	431	goto error;
	432	}
	433	uchan->id = trace_ust_get_next_chan_id(usess);
	434
	435	DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
	436	uchan->name,
	437	type,
	438	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_code = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
	447	goto error_free_chan;
	448	}
	449
	450	/* Adding the channel to the channel hash table. */
	451	rcu_read_lock();
	452	if (strncmp(uchan->name, DEFAULT_METADATA_NAME, sizeof(uchan->name)) != 0) {
	453	lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
	454	chan_published = true;
	455	} else {
	456	/*
	457	* Copy channel attribute to session if this is metadata so if NO
	458	* application exists we can access that data in the shadow copy during
	459	* the global update of newly registered application.
	460	*/
	461	memcpy(&usess->metadata_attr, &uchan->attr, sizeof(usess->metadata_attr));
	462	}
	463	rcu_read_unlock();
	464
	465	DBG2("Channel %s created successfully", uchan->name);
	466	if (domain != LTTNG_DOMAIN_UST) {
	467	struct agent *agt = trace_ust_find_agent(usess, domain);
	468
	469	if (!agt) {
	470	agt = agent_create(domain);
	471	if (!agt) {
	472	ret_code = LTTNG_ERR_NOMEM;
	473	goto error_remove_chan;
	474	}
	475	agent_add(agt, usess->agents);
	476	}
	477	}
	478
	479	channel_attr_destroy(defattr);
	480	return LTTNG_OK;
	481
	482	error_remove_chan:
	483	if (chan_published) {
	484	trace_ust_delete_channel(usess->domain_global.channels, uchan);
	485	}
	486	error_free_chan:
	487	trace_ust_destroy_channel(uchan);
	488	error:
	489	channel_attr_destroy(defattr);
	490	return ret_code;
	491	}
	492
	493	/*
	494	* Disable UST channel for session and domain.
	495	*/
	496	int channel_ust_disable(struct ltt_ust_session usess, struct ltt_ust_channel uchan)
	497	{
	498	int ret = LTTNG_OK;
	499
	500	LTTNG_ASSERT(usess);
	501	LTTNG_ASSERT(uchan);
	502
	503	/* Already disabled */
	504	if (uchan->enabled == 0) {
	505	DBG2("Channel UST %s already disabled", uchan->name);
	506	goto end;
	507	}
	508
	509	uchan->enabled = 0;
	510
	511	/*
	512	* If session is inactive we don't notify the tracer right away. We
	513	* wait for the next synchronization.
	514	*/
	515	if (!usess->active) {
	516	goto end;
	517	}
	518
	519	DBG2("Channel %s being disabled in UST global domain", uchan->name);
	520	/* Disable channel for global domain */
	521	ret = ust_app_disable_channel_glb(usess, uchan);
	522	if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
	523	ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
	524	goto error;
	525	}
	526
	527	DBG2("Channel %s disabled successfully", uchan->name);
	528
	529	return LTTNG_OK;
	530
	531	end:
	532	error:
	533	return ret;
	534	}
	535
	536	struct lttng_channel trace_ust_channel_to_lttng_channel(const struct ltt_ust_channel uchan)
	537	{
	538	struct lttng_channel channel = nullptr, ret = nullptr;
	539
	540	channel = lttng_channel_create_internal();
	541	if (!channel) {
	542	ERR("Failed to create lttng_channel during conversion from ltt_ust_channel to lttng_channel");
	543	goto end;
	544	}
	545
	546	if (lttng_strncpy(channel->name, uchan->name, LTTNG_SYMBOL_NAME_LEN)) {
	547	ERR("Failed to set channel name during conversion from ltt_ust_channel to lttng_channel");
	548	goto end;
	549	}
	550
	551	channel->attr.overwrite = uchan->attr.overwrite;
	552	channel->attr.subbuf_size = uchan->attr.subbuf_size;
	553	channel->attr.num_subbuf = uchan->attr.num_subbuf;
	554	channel->attr.switch_timer_interval = uchan->attr.switch_timer_interval;
	555	channel->attr.read_timer_interval = uchan->attr.read_timer_interval;
	556	channel->enabled = uchan->enabled;
	557	channel->attr.tracefile_size = uchan->tracefile_size;
	558	channel->attr.tracefile_count = uchan->tracefile_count;
	559
	560	/*
	561	* Map enum lttng_ust_output to enum lttng_event_output.
	562	*/
	563	switch (uchan->attr.output) {
	564	case LTTNG_UST_ABI_MMAP:
	565	channel->attr.output = LTTNG_EVENT_MMAP;
	566	break;
	567	default:
	568	/*
	569	* LTTNG_UST_MMAP is the only supported UST
	570	* output mode.
	571	*/
	572	abort();
	573	break;
	574	}
	575
	576	lttng_channel_set_blocking_timeout(channel, uchan->attr.u.s.blocking_timeout);
	577	lttng_channel_set_monitor_timer_interval(channel, uchan->monitor_timer_interval);
	578
	579	ret = channel;
	580	channel = nullptr;
	581
	582	end:
	583	lttng_channel_destroy(channel);
	584	return ret;
	585	}