X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=ltt-sessiond%2Fsession.c;h=97ab098dca3c93c102cc7042619783ec9dec02ec;hp=92111ffed981cc5f2593bc0770efc8c5f8e893aa;hb=b5541356f517dba006af9f676df8131dcb68f132;hpb=7a485870536daad1f6c5aeb1ae18783a8862cbee;ds=sidebyside diff --git a/ltt-sessiond/session.c b/ltt-sessiond/session.c index 92111ffed..97ab098dc 100644 --- a/ltt-sessiond/session.c +++ b/ltt-sessiond/session.c @@ -17,6 +17,7 @@ */ #define _GNU_SOURCE +#include #include #include #include @@ -26,63 +27,97 @@ #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 * @@ -94,12 +129,14 @@ struct ltt_session *find_session_by_name(char *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; @@ -111,26 +148,29 @@ struct ltt_session *find_session_by_name(char *name) /* * 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; } @@ -138,7 +178,7 @@ int destroy_session(char *name) /* * 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) { @@ -194,12 +234,6 @@ 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; @@ -209,10 +243,15 @@ int create_session(char *name, char *path) /* 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; @@ -240,9 +279,11 @@ void get_lttng_session(struct lttng_session *sessions) 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'; @@ -253,5 +294,6 @@ void get_lttng_session(struct lttng_session *sessions) /* Reset struct for next pass */ memset(&lsess, 0, sizeof(lsess)); } + pthread_mutex_unlock(<t_session_list.lock); }