Allow channel mode override in snapshot sessions
[lttng-tools.git] / src / bin / lttng-sessiond / channel.c
index 984576edc2e03b68595348f643dfa2e9c19ebdbb..88480c4b4e7b78fd63a2edc744618eadba0c36bc 100644 (file)
@@ -1,5 +1,6 @@
 /*
  * 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,
@@ -15,7 +16,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <inttypes.h>
 #include <string.h>
 #include <unistd.h>
@@ -30,6 +31,7 @@
 #include "ust-ctl.h"
 #include "utils.h"
 #include "ust-app.h"
+#include "agent.h"
 
 /*
  * Return allocated channel attributes.
@@ -38,6 +40,7 @@ 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) {
@@ -45,12 +48,6 @@ struct lttng_channel *channel_new_default_attr(int dom,
                goto error_alloc;
        }
 
-       if (snprintf(chan->name, sizeof(chan->name), "%s",
-                               DEFAULT_CHANNEL_NAME) < 0) {
-               PERROR("snprintf default channel name");
-               goto error;
-       }
-
        /* Same for all domains. */
        chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
        chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
@@ -65,8 +62,19 @@ struct lttng_channel *channel_new_default_attr(int dom,
                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();
@@ -76,6 +84,8 @@ struct lttng_channel *channel_new_default_attr(int dom,
                                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:
@@ -86,6 +96,8 @@ struct lttng_channel *channel_new_default_attr(int dom,
                                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;
@@ -93,6 +105,11 @@ struct lttng_channel *channel_new_default_attr(int dom,
                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:
@@ -162,6 +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.
  */
@@ -184,12 +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) {
@@ -256,6 +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);
 
@@ -267,14 +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
@@ -327,11 +396,12 @@ int channel_ust_create(struct ltt_ust_session *usess,
        }
 
        /* Create UST channel */
-       uchan = trace_ust_create_channel(attr);
+       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;
@@ -361,10 +431,33 @@ 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);
+       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;
This page took 0.026079 seconds and 4 git commands to generate.