afb-trace: improve and simplify session management

Change-Id: I828e0498bc68c9f1d1635a886e0a93fcb2d2389c
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

diff --git a/src/afb-trace.c b/src/afb-trace.c
index fb07795..cefd205 100644 (file)
--- a/src/afb-trace.c
+++ b/src/afb-trace.c
@@ -76,10 +76,9 @@ struct event {
 };
 
 /* struct for sessions */
-struct session {
-       struct session *next;           /* link to the next session */
-       struct afb_session *session;    /* the session */
-       struct afb_trace *trace;        /* the tracer */
+struct cookie {
+       struct afb_session *session;    /* the session */
+       struct afb_trace *trace;        /* the tracer */
 };
 
 /* struct for recording hooks */
@@ -88,7 +87,7 @@ struct hook {
        void *handler;                  /* the handler of the hook */
        struct event *event;            /* the associated event */
        struct tag *tag;                /* the associated tag */
-       struct session *session;        /* the associated session */
+       struct afb_session *session;    /* the associated session */
 };
 
 /* types of hooks */
@@ -111,7 +110,6 @@ struct afb_trace
        struct afb_session *bound;              /* bound to session */
        struct event *events;                   /* list of events */
        struct tag *tags;                       /* list of tags */
-       struct session *sessions;               /* list of tags */
        struct hook *hooks[Trace_Type_Count];   /* hooks */
 };
 
@@ -975,7 +973,7 @@ abstracting[Trace_Type_Count] =
 /*******************************************************************************/
 
 /* drop hooks of 'trace' matching 'tag' and 'event' and 'session' */
-static void trace_unhook(struct afb_trace *trace, struct tag *tag, struct event *event, struct session *session)
+static void trace_unhook(struct afb_trace *trace, struct tag *tag, struct event *event, struct afb_session *session)
 {
        int i;
        struct hook *hook, **prev;
@@ -1004,24 +1002,7 @@ static void trace_cleanup(struct afb_trace *trace)
        struct hook *hook;
        struct tag *tag, **ptag;
        struct event *event, **pevent;
-       struct session *session, **psession;
 
-       /* clean sessions */
-       psession = &trace->sessions;
-       while ((session = *psession)) {
-               /* search for session */
-               for (hook = NULL, i = 0 ; !hook && i < Trace_Type_Count ; i++)
-                       for (hook = trace->hooks[i] ; hook && hook->session != session ; hook = hook->next);
-               /* keep or free whether used or not */
-               if (hook)
-                       psession = &session->next;
-               else {
-                       *psession = session->next;
-                       if (__atomic_exchange_n(&session->trace, NULL, __ATOMIC_RELAXED))
-                               afb_session_set_cookie(session->session, session, NULL, NULL);
-                       free(session);
-               }
-       }
        /* clean tags */
        ptag = &trace->tags;
        while ((tag = *ptag)) {
@@ -1053,19 +1034,6 @@ static void trace_cleanup(struct afb_trace *trace)
        }
 }
 
-/* callback at end of traced session */
-static void free_session_cookie(void *cookie)
-{
-       struct session *session = cookie;
-       struct afb_trace *trace = __atomic_exchange_n(&session->trace, NULL, __ATOMIC_RELAXED);
-       if (trace) {
-               pthread_mutex_lock(&trace->mutex);
-               trace_unhook(trace, NULL, NULL, session);
-               trace_cleanup(trace);
-               pthread_mutex_unlock(&trace->mutex);
-       }
-}
-
 /*
  * Get the tag of 'name' within 'trace'.
  * If 'alloc' isn't zero, create the tag and add it.
@@ -1123,41 +1091,45 @@ static struct event *trace_get_event(struct afb_trace *trace, const char *name,
 }
 
 /*
- * Get the session of 'value' within 'trace'.
- * If 'alloc' isn't zero, create the session and add it.
+ * called on session closing
  */
-static struct session *trace_get_session(struct afb_trace *trace, struct afb_session *value, int alloc)
-{
-       struct session *session;
-
-       /* search the session */
-       session = trace->sessions;
-       while (session && session->session != value)
-               session = session->next;
-
-       if (!session && alloc) {
-               session = malloc(sizeof * session);
-               if (session) {
-                       session->session = value;
-                       session->trace = NULL;
-                       session->next = trace->sessions;
-                       trace->sessions = session;
-               }
-       }
-       return session;
+static void session_closed(void *item)
+{
+       struct cookie *cookie = item;
+
+       pthread_mutex_lock(&cookie->trace->mutex);
+       trace_unhook(cookie->trace, NULL, NULL, cookie->session);
+       pthread_mutex_unlock(&cookie->trace->mutex);
+       free(cookie);
+}
+
+/*
+ * records the cookie of session for tracking close
+ */
+static void *session_open(void *closure)
+{
+       struct cookie *param = closure, *cookie;
+       cookie = malloc(sizeof *cookie);
+       if (cookie)
+               *cookie = *param;
+       return cookie;
 }
 
 /*
  * Get the session of 'uuid' within 'trace'.
  * If 'alloc' isn't zero, create the session and add it.
  */
-static struct session *trace_get_session_by_uuid(struct afb_trace *trace, const char *uuid, int alloc)
+static struct afb_session *trace_get_session_by_uuid(struct afb_trace *trace, const char *uuid, int alloc)
 {
-       struct afb_session *session;
+       struct cookie cookie;
        int created;
 
-       session = afb_session_get(uuid, alloc ? &created : NULL);
-       return session ? trace_get_session(trace, session, alloc) : NULL;
+       cookie.session = afb_session_get(uuid, alloc ? &created : NULL);
+       if (cookie.session) {
+               cookie.trace = trace;
+               afb_session_cookie(cookie.session, cookie.trace, session_open, session_closed, &cookie, 0);
+       }
+       return cookie.session;
 }
 
 static struct hook *trace_make_detached_hook(struct afb_trace *trace, const char *event, const char *tag)
@@ -1178,13 +1150,8 @@ static struct hook *trace_make_detached_hook(struct afb_trace *trace, const char
 
 static void trace_attach_hook(struct afb_trace *trace, struct hook *hook, enum trace_type type)
 {
-       struct session *session = hook->session;
        hook->next = trace->hooks[type];
        trace->hooks[type] = hook;
-       if (session && !session->trace) {
-               session->trace = trace;
-               afb_session_set_cookie(session->session, session, session, free_session_cookie);
-       }
 }
 
 /*******************************************************************************/
@@ -1214,7 +1181,7 @@ struct desc
 static void addhook(struct desc *desc, enum trace_type type)
 {
        struct hook *hook;
-       struct session *session;
+       struct afb_session *session;
        struct afb_session *bind;
        struct afb_trace *trace = desc->context->trace;
 
@@ -1248,7 +1215,7 @@ static void addhook(struct desc *desc, enum trace_type type)
                                free(hook);
                                return;
                        }
-                       bind = session->session;
+                       bind = session;
                }
                hook->handler = afb_hook_create_xreq(desc->api, desc->verb, bind,
                                desc->flags[type], &hook_xreq_itf, hook);
@@ -1443,7 +1410,7 @@ static void drop_session(void *closure, struct json_object *object)
 {
        int rc;
        struct context *context = closure;
-       struct session *session;
+       struct afb_session *session;
        const char *uuid;
 
        rc = wrap_json_unpack(object, "s", &uuid);