Fix: validate number of subbuffers after tweaking properties

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

diff --git a/src/bin/lttng-sessiond/channel.c b/src/bin/lttng-sessiond/channel.c
index 817100ff449128e2f71705623d6ac4a39d95e0f4..d2a9447463b8d669eb5144741bf8fe690669151d 100644 (file)
--- a/src/bin/lttng-sessiond/channel.c
+++ b/src/bin/lttng-sessiond/channel.c
@@ -16,6 +16,7 @@
  */
 
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <inttypes.h>
 #include <string.h>
 #include <unistd.h>
@@ -167,6 +168,19 @@ 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.
  */
@@ -195,6 +209,12 @@ int channel_kernel_create(struct ltt_kernel_session *ksession,
                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) {
@@ -280,6 +300,12 @@ int channel_ust_create(struct ltt_ust_session *usess,
                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
@@ -332,11 +358,24 @@ int channel_ust_create(struct ltt_ust_session *usess,
        }
 
        /* Create UST channel */
-       uchan = trace_ust_create_channel(attr);
+       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;
@@ -366,7 +405,18 @@ int channel_ust_create(struct ltt_ust_session *usess,
 
        /* Adding the channel to the channel hash table. */
        rcu_read_lock();
-       lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
+       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);