X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fchannel.c;h=88480c4b4e7b78fd63a2edc744618eadba0c36bc;hp=7c95a0d2194d4e6de2e43e726b98ee05fcb2d2cd;hb=8d5841ea483139d3ab2f2b4dd39263dad63832b1;hpb=bdf640139afb02572eb23f014e4a61ad68fdfeb1

diff --git a/src/bin/lttng-sessiond/channel.c b/src/bin/lttng-sessiond/channel.c
index 7c95a0d21..88480c4b4 100644
--- a/src/bin/lttng-sessiond/channel.c
+++ b/src/bin/lttng-sessiond/channel.c
@@ -31,6 +31,7 @@
 #include "ust-ctl.h"
 #include "utils.h"
 #include "ust-app.h"
+#include "agent.h"
 
 /*
  * Return allocated channel attributes.
@@ -178,6 +179,19 @@ 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.
  */
@@ -200,12 +214,25 @@ int channel_kernel_create(struct ltt_kernel_session *ksession,
 		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) {
-		/* Force channel attribute for snapshot mode. */
-		attr->attr.overwrite = 1;
 		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) {
@@ -272,6 +299,7 @@ int channel_ust_create(struct ltt_ust_session *usess,
 	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);
 
@@ -283,14 +311,39 @@ int channel_ust_create(struct ltt_ust_session *usess,
 			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) {
-		/* Force channel attribute for snapshot mode. */
-		attr->attr.overwrite = 1;
 		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
@@ -343,24 +396,12 @@ int channel_ust_create(struct ltt_ust_session *usess,
 	}
 
 	/* Create UST channel */
-	uchan = trace_ust_create_channel(attr, LTTNG_DOMAIN_UST);
+	uchan = trace_ust_create_channel(attr, domain);
 	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;
@@ -405,6 +446,18 @@ int channel_ust_create(struct ltt_ust_session *usess,
 	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);
+		}
+	}
 
 	free(defattr);
 	return LTTNG_OK;