*/
#define _GNU_SOURCE
+#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lttngerr.h"
#include "session.h"
-/* Variables */
-static unsigned int session_count;
-
-/* Static internal function */
-static void add_session_list(struct ltt_session *ls);
-static void del_session_list(struct ltt_session *ls);
-
-/* Init global session list */
-struct ltt_session_list ltt_session_list = {
- .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
-};
-
/*
- * get_session_list
+ * NOTES:
*
- * Return a pointer to the session list.
+ * No ltt_session.lock is taken here because those data structure are widely
+ * spread across the lttng-tools code base so before caling functions below
+ * that can read/write a session, the caller MUST acquire the session lock
+ * using lock_session() and unlock_session().
*/
-struct ltt_session_list *get_session_list(void)
-{
- return <t_session_list;
-}
/*
- * get_session_count
+ * Init tracing session list.
*
- * Return session_count
+ * Please see session.h for more explanation and correct usage of the list.
*/
-unsigned int get_session_count(void)
-{
- return session_count;
-}
+static struct ltt_session_list ltt_session_list = {
+ .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
+ .lock = PTHREAD_MUTEX_INITIALIZER,
+ .count = 0,
+};
/*
* add_session_list
*
* Add a ltt_session structure to the global list.
+ *
+ * The caller MUST acquire the session list lock before.
*/
static void add_session_list(struct ltt_session *ls)
{
cds_list_add(&ls->list, <t_session_list.head);
- session_count++;
+ ltt_session_list.count++;
}
/*
* del_session_list
*
* Delete a ltt_session structure to the global list.
+ *
+ * The caller MUST acquire the session list lock before.
*/
static void del_session_list(struct ltt_session *ls)
{
cds_list_del(&ls->list);
/* Sanity check */
- if (session_count != 0) {
- session_count--;
+ if (ltt_session_list.count > 0) {
+ ltt_session_list.count--;
}
}
+/*
+ * get_session_list
+ *
+ * Return a pointer to the session list.
+ */
+struct ltt_session_list *get_session_list(void)
+{
+ return <t_session_list;
+}
+
+/*
+ * Acquire session lock
+ */
+void lock_session(struct ltt_session *session)
+{
+ pthread_mutex_lock(&session->lock);
+}
+
+/*
+ * Release session lock
+ */
+void unlock_session(struct ltt_session *session)
+{
+ pthread_mutex_unlock(&session->lock);
+}
+
+/*
+ * get_session_count
+ *
+ * Return session_count
+ */
+unsigned int get_session_count(void)
+{
+ unsigned int count;
+
+ pthread_mutex_lock(<t_session_list.lock);
+ count = ltt_session_list.count;
+ pthread_mutex_unlock(<t_session_list.lock);
+
+ return count;
+}
+
/*
* find_session_by_name
*
int found = 0;
struct ltt_session *iter;
+ pthread_mutex_lock(<t_session_list.lock);
cds_list_for_each_entry(iter, <t_session_list.head, list) {
if (strncmp(iter->name, name, strlen(name)) == 0) {
found = 1;
break;
}
}
+ pthread_mutex_unlock(<t_session_list.lock);
if (!found) {
iter = NULL;
/*
* destroy_session
*
- * Delete session from the global session list
- * and free the memory.
+ * Delete session from the session list and free the memory.
*
- * Return -1 if no session is found.
- * On success, return 1;
+ * Return -1 if no session is found. On success, return 1;
*/
int destroy_session(char *name)
{
int found = -1;
struct ltt_session *iter;
+ pthread_mutex_lock(<t_session_list.lock);
cds_list_for_each_entry(iter, <t_session_list.head, list) {
if (strcmp(iter->name, name) == 0) {
DBG("Destroying session %s", iter->name);
del_session_list(iter);
+ free(iter->name);
+ free(iter->path);
+ pthread_mutex_destroy(&iter->lock);
free(iter);
found = 1;
break;
}
}
+ pthread_mutex_unlock(<t_session_list.lock);
return found;
}
/*
* create_session
*
- * Create a brand new session and add it to the global session list.
+ * Create a brand new session and add it to the session list.
*/
int create_session(char *name, char *path)
{
goto error;
}
- /*
- * Set consumer (identifier) to 0. This means that there is
- * NO consumer attach to that session yet.
- */
- new_session->ust_consumer = 0;
-
/* Init kernel session */
new_session->kernel_session = NULL;
/* Set trace list counter */
new_session->ust_trace_count = 0;
- /* Add new session to the global session list */
+ /* Add new session to the session list */
+ pthread_mutex_lock(<t_session_list.lock);
add_session_list(new_session);
+ pthread_mutex_unlock(<t_session_list.lock);
+
+ /* Init lock */
+ pthread_mutex_init(&new_session->lock, NULL);
- DBG("Tracing session %s created in %s", name, new_session->path);
+ DBG("Tracing session %s created in %s", new_session->name, new_session->path);
return 0;
DBG("Getting all available session");
- /* Iterate over session list and append data after
- * the control struct in the buffer.
+ /*
+ * Iterate over session list and append data after the control struct in
+ * the buffer.
*/
+ pthread_mutex_lock(<t_session_list.lock);
cds_list_for_each_entry(iter, <t_session_list.head, list) {
strncpy(lsess.path, iter->path, sizeof(lsess.path));
lsess.path[sizeof(lsess.path) - 1] = '\0';
/* Reset struct for next pass */
memset(&lsess, 0, sizeof(lsess));
}
+ pthread_mutex_unlock(<t_session_list.lock);
}
projects / lttng-tools.git / blobdiff