Fix out of order channel insert in hash table

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

diff --git a/lttng-sessiond/channel.c b/lttng-sessiond/channel.c
index 146807cb21ccedc491734cc3572099e844f47c95..3dc04ccb83829ad2077dc2ced938d3ee6c40671b 100644 (file)
--- a/lttng-sessiond/channel.c
+++ b/lttng-sessiond/channel.c
@@ -15,18 +15,20 @@
  * Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 
+#define _GNU_SOURCE
 #include <string.h>
 #include <unistd.h>
 
 #include <lttng/lttng.h>
+#include <lttng-ht.h>
 #include <lttng-sessiond-comm.h>
 #include <lttngerr.h>
 
 #include "channel.h"
-#include "hashtable.h"
 #include "kernel.h"
 #include "ust-ctl.h"
 #include "utils.h"
+#include "ust-app.h"
 
 /*
  * Return allocated channel attributes.
@@ -37,13 +39,13 @@ struct lttng_channel *channel_new_default_attr(int dom)
 
        chan = zmalloc(sizeof(struct lttng_channel));
        if (chan == NULL) {
-               perror("zmalloc channel init");
+               PERROR("zmalloc channel init");
                goto error_alloc;
        }
 
        if (snprintf(chan->name, sizeof(chan->name), "%s",
                                DEFAULT_CHANNEL_NAME) < 0) {
-               perror("snprintf default channel name");
+               PERROR("snprintf default channel name");
                goto error;
        }
 
@@ -90,10 +92,8 @@ int channel_kernel_disable(struct ltt_kernel_session *ksession,
                goto error;
        } else if (kchan->enabled == 1) {
                ret = kernel_disable_channel(kchan);
-               if (ret < 0) {
-                       if (ret != EEXIST) {
-                               ret = LTTCOMM_KERN_CHAN_DISABLE_FAIL;
-                       }
+               if (ret < 0 && ret != -EEXIST) {
+                       ret = LTTCOMM_KERN_CHAN_DISABLE_FAIL;
                        goto error;
                }
        }
@@ -164,3 +164,161 @@ error:
        free(defattr);
        return ret;
 }
+
+/*
+ * Enable UST channel for session and domain.
+ */
+int channel_ust_enable(struct ltt_ust_session *usess, int domain,
+               struct ltt_ust_channel *uchan)
+{
+       int ret = LTTCOMM_OK;
+
+       /* If already enabled, everything is OK */
+       if (uchan->enabled) {
+               DBG3("Channel %s already enabled. Skipping", uchan->name);
+               goto end;
+       }
+
+       switch (domain) {
+       case LTTNG_DOMAIN_UST:
+               DBG2("Channel %s being enabled in UST global domain", uchan->name);
+               /* Enable channel for global domain */
+               ret = ust_app_enable_channel_glb(usess, uchan);
+               break;
+       case LTTNG_DOMAIN_UST_PID:
+       case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
+       case LTTNG_DOMAIN_UST_EXEC_NAME:
+               ret = LTTCOMM_NOT_IMPLEMENTED;
+               goto error;
+       }
+
+       if (ret < 0) {
+               if (ret != -EEXIST) {
+                       ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
+                       goto error;
+               } else {
+                       ret = LTTCOMM_OK;
+               }
+       }
+
+       uchan->enabled = 1;
+       DBG2("Channel %s enabled successfully", uchan->name);
+
+end:
+error:
+       return ret;
+}
+
+/*
+ * Create UST channel for session and domain.
+ */
+int channel_ust_create(struct ltt_ust_session *usess, int domain,
+               struct lttng_channel *attr)
+{
+       int ret = LTTCOMM_OK;
+       struct lttng_ht *chan_ht;
+       struct ltt_ust_channel *uchan = NULL;
+       struct lttng_channel *defattr = NULL;
+
+       /* Creating channel attributes if needed */
+       if (attr == NULL) {
+               defattr = channel_new_default_attr(domain);
+               if (defattr == NULL) {
+                       ret = LTTCOMM_FATAL;
+                       goto error;
+               }
+               attr = defattr;
+       }
+
+       /* Create UST channel */
+       uchan = trace_ust_create_channel(attr, usess->pathname);
+       if (uchan == NULL) {
+               ret = LTTCOMM_FATAL;
+               goto error;
+       }
+       uchan->enabled = 1;
+
+       switch (domain) {
+       case LTTNG_DOMAIN_UST:
+               DBG2("Channel %s being created in UST global domain", uchan->name);
+
+               /* Adding the channel to the channel hash table. */
+               rcu_read_lock();
+               lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
+               rcu_read_unlock();
+
+               /* Enable channel for global domain */
+               ret = ust_app_create_channel_glb(usess, uchan);
+               break;
+       case LTTNG_DOMAIN_UST_PID:
+       case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
+       case LTTNG_DOMAIN_UST_EXEC_NAME:
+       default:
+               ret = LTTCOMM_NOT_IMPLEMENTED;
+               goto error_free_chan;
+       }
+
+       if (ret < 0 && ret != -EEXIST) {
+               ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
+               goto error_free_chan;
+       }
+
+       DBG2("Channel %s created successfully", uchan->name);
+
+       free(defattr);
+       return LTTCOMM_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:
+       free(defattr);
+       return ret;
+}
+
+/*
+ * Disable UST channel for session and domain.
+ */
+int channel_ust_disable(struct ltt_ust_session *usess, int domain,
+               struct ltt_ust_channel *uchan)
+{
+       int ret = LTTCOMM_OK;
+
+       /* Already disabled */
+       if (uchan->enabled == 0) {
+               DBG2("Channel UST %s already disabled", uchan->name);
+               goto end;
+       }
+
+       /* Get the right channel's hashtable */
+       switch (domain) {
+       case LTTNG_DOMAIN_UST:
+               DBG2("Channel %s being disabled in UST global domain", uchan->name);
+               /* Disable channel for global domain */
+               ret = ust_app_disable_channel_glb(usess, uchan);
+               break;
+       case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
+       case LTTNG_DOMAIN_UST_EXEC_NAME:
+       case LTTNG_DOMAIN_UST_PID:
+               ret = LTTCOMM_NOT_IMPLEMENTED;
+               goto error;
+       }
+
+       if (ret < 0 && ret != -EEXIST) {
+               ret = LTTCOMM_UST_DISABLE_FAIL;
+               goto error;
+       }
+
+       uchan->enabled = 0;
+
+       DBG2("Channel %s disabled successfully", uchan->name);
+
+       return LTTCOMM_OK;
+
+end:
+error:
+       return ret;
+}