static void test_create_ust_channel(void)
{
struct ltt_ust_channel *uchan;
struct lttng_channel attr;
memset(&attr, 0, sizeof(attr));
strncpy(attr.name, "channel0", 8);
uchan = trace_ust_create_channel(&attr);
ok(uchan != NULL, "Create UST channel");
ok(uchan->enabled == 0 &&
strncmp(uchan->name, "channel0", 8) == 0 &&
uchan->name[LTTNG_UST_SYM_NAME_LEN - 1] == '\0' &&
uchan->ctx != NULL &&
uchan->events != NULL &&
uchan->attr.overwrite == attr.attr.overwrite,
"Validate UST channel");
trace_ust_destroy_channel(uchan);
}
/*
* 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;
}
