Add hooking of daemon interface
[src/app-framework-binder.git] / src / afb-hook.c
index f59192a..2e0255d 100644 (file)
 
 #define _GNU_SOURCE
 
+#include <limits.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <string.h>
+#include <pthread.h>
+#include <unistd.h>
 
 #include <json-c/json.h>
 
 #include "afb-context.h"
 #include "afb-hook.h"
 #include "afb-session.h"
+#include "afb-xreq.h"
+#include "afb-ditf.h"
 #include "verbose.h"
 
-/*
- * Definition of a hook
+/**
+ * Definition of a hook for xreq
  */
-struct afb_hook {
-       struct afb_hook *next; /* next hook */
-       unsigned refcount; /* reference count */
-       char *api; /* api hooked or NULL for any */
-       char *verb; /* verb hooked or NULL for any */
-       struct afb_session *session; /* session hooked or NULL if any */
-       unsigned flags; /* hook flags */
-       struct afb_hook_req_itf *reqitf; /* interface of hook */
-       void *closure; /* closure for callbacks */
+struct afb_hook_xreq {
+       struct afb_hook_xreq *next; /**< next hook */
+       unsigned refcount; /**< reference count */
+       char *api; /**< api hooked or NULL for any */
+       char *verb; /**< verb hooked or NULL for any */
+       struct afb_session *session; /**< session hooked or NULL if any */
+       unsigned flags; /**< hook flags */
+       struct afb_hook_xreq_itf *itf; /**< interface of hook */
+       void *closure; /**< closure for callbacks */
 };
 
-/*
- * Link hooks to a hooked request
+/**
+ * Definition of a hook for ditf
  */
-struct hook_req_observer {
-       struct afb_hook *hook; /* the hook */
-       struct hook_req_observer *next; /* the next observer */
+struct afb_hook_ditf {
+       struct afb_hook_ditf *next; /**< next hook */
+       unsigned refcount; /**< reference count */
+       char *api; /**< api hooked or NULL for any */
+       unsigned flags; /**< hook flags */
+       struct afb_hook_ditf_itf *itf; /**< interface of hook */
+       void *closure; /**< closure for callbacks */
 };
 
-/*
- * Structure recording a request to hook
- */
-struct afb_hook_req {
-       struct hook_req_observer *observers; /* observers */
-       struct afb_context *context; /* context of the request */
-       struct afb_req req; /* the request hookd */
-       unsigned refcount; /* reference count proxy for request */
-       char name[1]; /* hook info for the request */
-};
+/* synchronisation across threads */
+static pthread_rwlock_t rwlock = PTHREAD_RWLOCK_INITIALIZER;
 
-/*
- * Structure for handling subcalls callbacks
- */
-struct hook_subcall {
-       struct afb_hook_req *tr; /* hookd request */
-       void (*callback)(void*, int, struct json_object*); /* client callback */
-       void *cb_closure; /* cient closure */
-};
-
-/* counter of hooking */
-static unsigned hook_count = 0;
+/* list of hooks for xreq */
+static struct afb_hook_xreq *list_of_xreq_hooks = NULL;
 
-/* list of hooks */
-static struct afb_hook *list_of_hooks = NULL;
+/* list of hooks for ditf */
+static struct afb_hook_ditf *list_of_ditf_hooks = NULL;
 
 /******************************************************************************
  * section: default callbacks for tracing requests
  *****************************************************************************/
 
-static void _hook_(const struct afb_hook_req *tr, const char *format, ...)
+static void _hook_xreq_(const struct afb_xreq *xreq, const char *format, ...)
 {
        int len;
        char *buffer;
@@ -94,499 +86,642 @@ static void _hook_(const struct afb_hook_req *tr, const char *format, ...)
        va_end(ap);
 
        if (len < 0)
-               NOTICE("tracing %s allocation error", tr->name);
+               NOTICE("hook xreq-%06d:%s/%s allocation error", xreq->hookindex, xreq->api, xreq->verb);
        else {
-               NOTICE("hook %s %s", tr->name, buffer);
+               NOTICE("hook xreq-%06d:%s/%s %s", xreq->hookindex, xreq->api, xreq->verb, buffer);
                free(buffer);
        }
 }
 
-static void hook_req_begin_default_cb(void * closure, const struct afb_hook_req *tr)
+static void hook_xreq_begin_default_cb(void * closure, const struct afb_xreq *xreq)
 {
-       _hook_(tr, "BEGIN");
+       _hook_xreq_(xreq, "BEGIN");
 }
 
-static void hook_req_end_default_cb(void * closure, const struct afb_hook_req *tr)
+static void hook_xreq_end_default_cb(void * closure, const struct afb_xreq *xreq)
 {
-       _hook_(tr, "END");
+       _hook_xreq_(xreq, "END");
 }
 
-static void hook_req_json_default_cb(void * closure, const struct afb_hook_req *tr, struct json_object *obj)
+static void hook_xreq_json_default_cb(void * closure, const struct afb_xreq *xreq, struct json_object *obj)
 {
-       _hook_(tr, "json() -> %s", json_object_to_json_string(obj));
+       _hook_xreq_(xreq, "json() -> %s", json_object_to_json_string(obj));
 }
 
-static void hook_req_get_default_cb(void * closure, const struct afb_hook_req *tr, const char *name, struct afb_arg arg)
+static void hook_xreq_get_default_cb(void * closure, const struct afb_xreq *xreq, const char *name, struct afb_arg arg)
 {
-       _hook_(tr, "get(%s) -> { name: %s, value: %s, path: %s }", name, arg.name, arg.value, arg.path);
+       _hook_xreq_(xreq, "get(%s) -> { name: %s, value: %s, path: %s }", name, arg.name, arg.value, arg.path);
 }
 
-static void hook_req_success_default_cb(void * closure, const struct afb_hook_req *tr, struct json_object *obj, const char *info)
+static void hook_xreq_success_default_cb(void * closure, const struct afb_xreq *xreq, struct json_object *obj, const char *info)
 {
-       _hook_(tr, "success(%s, %s)", json_object_to_json_string(obj), info);
+       _hook_xreq_(xreq, "success(%s, %s)", json_object_to_json_string(obj), info);
 }
 
-static void hook_req_fail_default_cb(void * closure, const struct afb_hook_req *tr, const char *status, const char *info)
+static void hook_xreq_fail_default_cb(void * closure, const struct afb_xreq *xreq, const char *status, const char *info)
 {
-       _hook_(tr, "fail(%s, %s)", status, info);
+       _hook_xreq_(xreq, "fail(%s, %s)", status, info);
 }
 
-static void hook_req_raw_default_cb(void * closure, const struct afb_hook_req *tr, const char *buffer, size_t size)
+static void hook_xreq_raw_default_cb(void * closure, const struct afb_xreq *xreq, const char *buffer, size_t size)
 {
-       _hook_(tr, "raw() -> %.*s", (int)size, buffer);
+       _hook_xreq_(xreq, "raw() -> %.*s", (int)size, buffer);
 }
 
-static void hook_req_send_default_cb(void * closure, const struct afb_hook_req *tr, const char *buffer, size_t size)
+static void hook_xreq_send_default_cb(void * closure, const struct afb_xreq *xreq, const char *buffer, size_t size)
 {
-       _hook_(tr, "send(%.*s)", (int)size, buffer);
+       _hook_xreq_(xreq, "send(%.*s)", (int)size, buffer);
 }
 
-static void hook_req_context_get_default_cb(void * closure, const struct afb_hook_req *tr, void *value)
+static void hook_xreq_context_get_default_cb(void * closure, const struct afb_xreq *xreq, void *value)
 {
-       _hook_(tr, "context_get() -> %p", value);
+       _hook_xreq_(xreq, "context_get() -> %p", value);
 }
 
-static void hook_req_context_set_default_cb(void * closure, const struct afb_hook_req *tr, void *value, void (*free_value)(void*))
+static void hook_xreq_context_set_default_cb(void * closure, const struct afb_xreq *xreq, void *value, void (*free_value)(void*))
 {
-       _hook_(tr, "context_set(%p, %p)", value, free_value);
+       _hook_xreq_(xreq, "context_set(%p, %p)", value, free_value);
 }
 
-static void hook_req_addref_default_cb(void * closure, const struct afb_hook_req *tr)
+static void hook_xreq_addref_default_cb(void * closure, const struct afb_xreq *xreq)
 {
-       _hook_(tr, "addref()");
+       _hook_xreq_(xreq, "addref()");
 }
 
-static void hook_req_unref_default_cb(void * closure, const struct afb_hook_req *tr)
+static void hook_xreq_unref_default_cb(void * closure, const struct afb_xreq *xreq)
 {
-       _hook_(tr, "unref()");
+       _hook_xreq_(xreq, "unref()");
 }
 
-static void hook_req_session_close_default_cb(void * closure, const struct afb_hook_req *tr)
+static void hook_xreq_session_close_default_cb(void * closure, const struct afb_xreq *xreq)
 {
-       _hook_(tr, "session_close()");
+       _hook_xreq_(xreq, "session_close()");
 }
 
-static void hook_req_session_set_LOA_default_cb(void * closure, const struct afb_hook_req *tr, unsigned level, int result)
+static void hook_xreq_session_set_LOA_default_cb(void * closure, const struct afb_xreq *xreq, unsigned level, int result)
 {
-       _hook_(tr, "session_set_LOA(%u) -> %d", level, result);
+       _hook_xreq_(xreq, "session_set_LOA(%u) -> %d", level, result);
 }
 
-static void hook_req_subscribe_default_cb(void * closure, const struct afb_hook_req *tr, struct afb_event event, int result)
+static void hook_xreq_subscribe_default_cb(void * closure, const struct afb_xreq *xreq, struct afb_event event, int result)
 {
-       _hook_(tr, "subscribe(%s:%p) -> %d", afb_event_name(event), event.closure, result);
+       _hook_xreq_(xreq, "subscribe(%s:%p) -> %d", afb_event_name(event), event.closure, result);
 }
 
-static void hook_req_unsubscribe_default_cb(void * closure, const struct afb_hook_req *tr, struct afb_event event, int result)
+static void hook_xreq_unsubscribe_default_cb(void * closure, const struct afb_xreq *xreq, struct afb_event event, int result)
 {
-       _hook_(tr, "unsubscribe(%s:%p) -> %d", afb_event_name(event), event.closure, result);
+       _hook_xreq_(xreq, "unsubscribe(%s:%p) -> %d", afb_event_name(event), event.closure, result);
 }
 
-static void hook_req_subcall_default_cb(void * closure, const struct afb_hook_req *tr, const char *api, const char *verb, struct json_object *args)
+static void hook_xreq_subcall_default_cb(void * closure, const struct afb_xreq *xreq, const char *api, const char *verb, struct json_object *args)
 {
-       _hook_(tr, "subcall(%s/%s, %s) ...", api, verb, json_object_to_json_string(args));
+       _hook_xreq_(xreq, "subcall(%s/%s, %s) ...", api, verb, json_object_to_json_string(args));
 }
 
-static void hook_req_subcall_result_default_cb(void * closure, const struct afb_hook_req *tr, int status, struct json_object *result)
+static void hook_xreq_subcall_result_default_cb(void * closure, const struct afb_xreq *xreq, int status, struct json_object *result)
 {
-       _hook_(tr, "    ...subcall... -> %d: %s", status, json_object_to_json_string(result));
+       _hook_xreq_(xreq, "    ...subcall... -> %d: %s", status, json_object_to_json_string(result));
 }
 
-static struct afb_hook_req_itf hook_req_default_itf = {
-       .hook_req_begin = hook_req_begin_default_cb,
-       .hook_req_end = hook_req_end_default_cb,
-       .hook_req_json = hook_req_json_default_cb,
-       .hook_req_get = hook_req_get_default_cb,
-       .hook_req_success = hook_req_success_default_cb,
-       .hook_req_fail = hook_req_fail_default_cb,
-       .hook_req_raw = hook_req_raw_default_cb,
-       .hook_req_send = hook_req_send_default_cb,
-       .hook_req_context_get = hook_req_context_get_default_cb,
-       .hook_req_context_set = hook_req_context_set_default_cb,
-       .hook_req_addref = hook_req_addref_default_cb,
-       .hook_req_unref = hook_req_unref_default_cb,
-       .hook_req_session_close = hook_req_session_close_default_cb,
-       .hook_req_session_set_LOA = hook_req_session_set_LOA_default_cb,
-       .hook_req_subscribe = hook_req_subscribe_default_cb,
-       .hook_req_unsubscribe = hook_req_unsubscribe_default_cb,
-       .hook_req_subcall = hook_req_subcall_default_cb,
-       .hook_req_subcall_result = hook_req_subcall_result_default_cb,
+static void hook_xreq_subcallsync_default_cb(void * closure, const struct afb_xreq *xreq, const char *api, const char *verb, struct json_object *args)
+{
+       _hook_xreq_(xreq, "subcallsync(%s/%s, %s) ...", api, verb, json_object_to_json_string(args));
+}
+
+static void hook_xreq_subcallsync_result_default_cb(void * closure, const struct afb_xreq *xreq, int status, struct json_object *result)
+{
+       _hook_xreq_(xreq, "    ...subcallsync... -> %d: %s", status, json_object_to_json_string(result));
+}
+
+static struct afb_hook_xreq_itf hook_xreq_default_itf = {
+       .hook_xreq_begin = hook_xreq_begin_default_cb,
+       .hook_xreq_end = hook_xreq_end_default_cb,
+       .hook_xreq_json = hook_xreq_json_default_cb,
+       .hook_xreq_get = hook_xreq_get_default_cb,
+       .hook_xreq_success = hook_xreq_success_default_cb,
+       .hook_xreq_fail = hook_xreq_fail_default_cb,
+       .hook_xreq_raw = hook_xreq_raw_default_cb,
+       .hook_xreq_send = hook_xreq_send_default_cb,
+       .hook_xreq_context_get = hook_xreq_context_get_default_cb,
+       .hook_xreq_context_set = hook_xreq_context_set_default_cb,
+       .hook_xreq_addref = hook_xreq_addref_default_cb,
+       .hook_xreq_unref = hook_xreq_unref_default_cb,
+       .hook_xreq_session_close = hook_xreq_session_close_default_cb,
+       .hook_xreq_session_set_LOA = hook_xreq_session_set_LOA_default_cb,
+       .hook_xreq_subscribe = hook_xreq_subscribe_default_cb,
+       .hook_xreq_unsubscribe = hook_xreq_unsubscribe_default_cb,
+       .hook_xreq_subcall = hook_xreq_subcall_default_cb,
+       .hook_xreq_subcall_result = hook_xreq_subcall_result_default_cb,
+       .hook_xreq_subcallsync = hook_xreq_subcallsync_default_cb,
+       .hook_xreq_subcallsync_result = hook_xreq_subcallsync_result_default_cb,
 };
 
 /******************************************************************************
- * section: macro for tracing requests
+ * section: hooks for tracing requests
  *****************************************************************************/
 
-#define TRACE_REQX(what,tr) do{\
-               struct hook_req_observer *observer = tr->observers;\
-               while (observer != NULL) {\
-                       struct afb_hook *hook = observer->hook;\
-                       observer = observer->next;\
-                       if (hook->reqitf && hook->reqitf->hook_req_##what)\
-                               hook->reqitf->hook_req_##what(hook->closure, tr);\
-               }\
-       }while(0)
-
-#define TRACE_REQ_(what,tr) do{\
-               struct hook_req_observer *observer = tr->observers;\
-               while (observer != NULL) {\
-                       struct afb_hook *hook = observer->hook;\
-                       observer = observer->next;\
-                       if ((hook->flags & afb_hook_flag_req_##what) && hook->reqitf && hook->reqitf->hook_req_##what)\
-                               hook->reqitf->hook_req_##what(hook->closure, tr);\
-               }\
-       }while(0)
-
-#define TRACE_REQ(what,tr,...) do{\
-               struct hook_req_observer *observer = tr->observers;\
-               while (observer != NULL) {\
-                       struct afb_hook *hook = observer->hook;\
-                       observer = observer->next;\
-                       if ((hook->flags & afb_hook_flag_req_##what) && hook->reqitf && hook->reqitf->hook_req_##what)\
-                               hook->reqitf->hook_req_##what(hook->closure, tr, __VA_ARGS__);\
-               }\
-       }while(0)
+#define _HOOK_XREQ_(what,...)   \
+       struct afb_hook_xreq *hook; \
+       pthread_rwlock_rdlock(&rwlock); \
+       hook = list_of_xreq_hooks; \
+       while (hook) { \
+               if (hook->itf->hook_xreq_##what \
+                && (hook->flags & afb_hook_flag_req_##what) != 0 \
+                && (!hook->session || hook->session == xreq->context.session) \
+                && (!hook->api || !strcasecmp(hook->api, xreq->api)) \
+                && (!hook->verb || !strcasecmp(hook->verb, xreq->verb))) { \
+                       hook->itf->hook_xreq_##what(hook->closure, __VA_ARGS__); \
+               } \
+               hook = hook->next; \
+       } \
+       pthread_rwlock_unlock(&rwlock);
 
-/******************************************************************************
- * section: afb_hook_req handling
- *****************************************************************************/
 
-static void hook_req_addref(struct afb_hook_req *tr)
+void afb_hook_xreq_begin(const struct afb_xreq *xreq)
 {
-       tr->refcount++;
+       _HOOK_XREQ_(begin, xreq);
 }
 
-static void hook_req_unref(struct afb_hook_req *tr)
+void afb_hook_xreq_end(const struct afb_xreq *xreq)
 {
-       struct hook_req_observer *o1, *o2;
-       if (!--tr->refcount) {
-               TRACE_REQX(end, tr);
-               afb_req_unref(tr->req);
-               o1 = tr->observers;
-               while(o1) {
-                       afb_hook_unref(o1->hook);
-                       o2 = o1->next;
-                       free(o1);
-                       o1 = o2;
-               }
-               free(tr);
-       }
+       _HOOK_XREQ_(end, xreq);
 }
 
-static struct afb_hook_req *hook_req_create(struct afb_req req, struct afb_context *context, const char *api, const char *verb)
+struct json_object *afb_hook_xreq_json(const struct afb_xreq *xreq, struct json_object *obj)
 {
-       int len;
-       char name[257];
-       unsigned id;
-       struct afb_hook_req *tr;
-
-       /* get the call id */
-       id = ++hook_count;
-       if (id == 1000000)
-               id = hook_count = 1;
-
-       /* creates the name */
-       len = snprintf(name, sizeof name, "%06d:%s/%s", id, api, verb);
-       if (len < 0 || (size_t)len >= sizeof name) {
-               tr = NULL;
-       } else {
-               tr = malloc(sizeof *tr + (size_t)len);
-               if (tr != NULL) {
-                       /* init hook */
-                       tr->observers = NULL;
-                       tr->refcount = 1;
-                       tr->context = context;
-                       tr->req = req;
-                       afb_req_addref(req);
-                       memcpy(tr->name, name, (size_t)(len + 1));
-               }
-       }
-       return tr;
+       _HOOK_XREQ_(json, xreq, obj);
+       return obj;
 }
 
-static void hook_req_add_observer(struct afb_hook_req *tr, struct afb_hook *hook)
+struct afb_arg afb_hook_xreq_get(const struct afb_xreq *xreq, const char *name, struct afb_arg arg)
 {
-       struct hook_req_observer *observer;
-
-       observer = malloc(sizeof *observer);
-       if (observer) {
-               observer->hook = afb_hook_addref(hook);
-               observer->next = tr->observers;
-               tr->observers = observer;
-       }
+       _HOOK_XREQ_(get, xreq, name, arg);
+       return arg;
 }
 
-/******************************************************************************
- * section: hooks for tracing requests
- *****************************************************************************/
+void afb_hook_xreq_success(const struct afb_xreq *xreq, struct json_object *obj, const char *info)
+{
+       _HOOK_XREQ_(success, xreq, obj, info);
+}
 
-static struct json_object *req_hook_json(void *closure)
+void afb_hook_xreq_fail(const struct afb_xreq *xreq, const char *status, const char *info)
 {
-       struct afb_hook_req *tr = closure;
-       struct json_object *r;
+       _HOOK_XREQ_(fail, xreq, status, info);
+}
 
-       r = afb_req_json(tr->req);
-       TRACE_REQ(json, tr, r);
-       return r;
+const char *afb_hook_xreq_raw(const struct afb_xreq *xreq, const char *buffer, size_t size)
+{
+       _HOOK_XREQ_(raw, xreq, buffer, size);
+       return buffer;
 }
 
-static struct afb_arg req_hook_get(void *closure, const char *name)
+void afb_hook_xreq_send(const struct afb_xreq *xreq, const char *buffer, size_t size)
 {
-       struct afb_hook_req *tr = closure;
-       struct afb_arg a;
+       _HOOK_XREQ_(send, xreq, buffer, size);
+}
 
-       a = afb_req_get(tr->req, name);
-       TRACE_REQ(get, tr, name, a);
-       return a;
+void *afb_hook_xreq_context_get(const struct afb_xreq *xreq, void *value)
+{
+       _HOOK_XREQ_(context_get, xreq, value);
+       return value;
 }
 
-static void req_hook_success(void *closure, struct json_object *obj, const char *info)
+void afb_hook_xreq_context_set(const struct afb_xreq *xreq, void *value, void (*free_value)(void*))
 {
-       struct afb_hook_req *tr = closure;
+       _HOOK_XREQ_(context_set, xreq, value, free_value);
+}
 
-       TRACE_REQ(success, tr, obj, info);
-       afb_req_success(tr->req, obj, info);
-       hook_req_unref(tr);
+void afb_hook_xreq_addref(const struct afb_xreq *xreq)
+{
+       _HOOK_XREQ_(addref, xreq);
 }
 
-static void req_hook_fail(void *closure, const char *status, const char *info)
+void afb_hook_xreq_unref(const struct afb_xreq *xreq)
 {
-       struct afb_hook_req *tr = closure;
+       _HOOK_XREQ_(unref, xreq);
+}
 
-       TRACE_REQ(fail, tr, status, info);
-       afb_req_fail(tr->req, status, info);
-       hook_req_unref(tr);
+void afb_hook_xreq_session_close(const struct afb_xreq *xreq)
+{
+       _HOOK_XREQ_(session_close, xreq);
 }
 
-static const char *req_hook_raw(void *closure, size_t *size)
+int afb_hook_xreq_session_set_LOA(const struct afb_xreq *xreq, unsigned level, int result)
 {
-       struct afb_hook_req *tr = closure;
-       const char *r;
-       size_t s;
+       _HOOK_XREQ_(session_set_LOA, xreq, level, result);
+       return result;
+}
 
-       r = afb_req_raw(tr->req, &s);
-       TRACE_REQ(raw, tr, r, s);
-       if (size)
-               *size = s;
-       return r;
+int afb_hook_xreq_subscribe(const struct afb_xreq *xreq, struct afb_event event, int result)
+{
+       _HOOK_XREQ_(subscribe, xreq, event, result);
+       return result;
 }
 
-static void req_hook_send(void *closure, const char *buffer, size_t size)
+int afb_hook_xreq_unsubscribe(const struct afb_xreq *xreq, struct afb_event event, int result)
 {
-       struct afb_hook_req *tr = closure;
+       _HOOK_XREQ_(unsubscribe, xreq, event, result);
+       return result;
+}
 
-       TRACE_REQ(send, tr, buffer, size);
-       afb_req_send(tr->req, buffer, size);
+void afb_hook_xreq_subcall(const struct afb_xreq *xreq, const char *api, const char *verb, struct json_object *args)
+{
+       _HOOK_XREQ_(subcall, xreq, api, verb, args);
 }
 
-static void *req_hook_context_get(void *closure)
+void afb_hook_xreq_subcall_result(const struct afb_xreq *xreq, int status, struct json_object *result)
 {
-       struct afb_hook_req *tr = closure;
-       void *r;
+       _HOOK_XREQ_(subcall_result, xreq, status, result);
+}
 
-       r = afb_req_context_get(tr->req);
-       TRACE_REQ(context_get, tr, r);
+void afb_hook_xreq_subcallsync(const struct afb_xreq *xreq, const char *api, const char *verb, struct json_object *args)
+{
+       _HOOK_XREQ_(subcallsync, xreq, api, verb, args);
+}
 
-       return r;
+int afb_hook_xreq_subcallsync_result(const struct afb_xreq *xreq, int status, struct json_object *result)
+{
+       _HOOK_XREQ_(subcallsync_result, xreq, status, result);
+       return status;
 }
 
-static void req_hook_context_set(void *closure, void *value, void (*free_value)(void*))
+/******************************************************************************
+ * section: 
+ *****************************************************************************/
+
+void afb_hook_init_xreq(struct afb_xreq *xreq)
 {
-       struct afb_hook_req *tr = closure;
+       static int reqindex;
 
-       TRACE_REQ(context_set, tr, value, free_value);
-       afb_req_context_set(tr->req, value, free_value);
+       int f, flags;
+       int add;
+       struct afb_hook_xreq *hook;
+
+       /* scan hook list to get the expected flags */
+       flags = 0;
+       pthread_rwlock_rdlock(&rwlock);
+       hook = list_of_xreq_hooks;
+       while (hook) {
+               f = hook->flags & afb_hook_flags_req_all;
+               add = f != 0
+                  && (!hook->session || hook->session == xreq->context.session)
+                  && (!hook->api || !strcasecmp(hook->api, xreq->api))
+                  && (!hook->verb || !strcasecmp(hook->verb, xreq->verb));
+               if (add)
+                       flags |= f;
+               hook = hook->next;
+       }
+       pthread_rwlock_unlock(&rwlock);
+
+       /* store the hooking data */
+       xreq->hookflags = flags;
+       if (flags) {
+               pthread_rwlock_wrlock(&rwlock);
+               if (++reqindex < 0)
+                       reqindex = 1;
+               xreq->hookindex = reqindex;
+               pthread_rwlock_unlock(&rwlock);
+       }
 }
 
-static void req_hook_addref(void *closure)
+struct afb_hook_xreq *afb_hook_create_xreq(const char *api, const char *verb, struct afb_session *session, int flags, struct afb_hook_xreq_itf *itf, void *closure)
 {
-       struct afb_hook_req *tr = closure;
+       struct afb_hook_xreq *hook;
+
+       /* alloc the result */
+       hook = calloc(1, sizeof *hook);
+       if (hook == NULL)
+               return NULL;
+
+       /* get a copy of the names */
+       hook->api = api ? strdup(api) : NULL;
+       hook->verb = verb ? strdup(verb) : NULL;
+       if ((api && !hook->api) || (verb && !hook->verb)) {
+               free(hook->api);
+               free(hook->verb);
+               free(hook);
+               return NULL;
+       }
+
+       /* initialise the rest */
+       hook->session = session;
+       if (session)
+               afb_session_addref(session);
+       hook->refcount = 1;
+       hook->flags = flags;
+       hook->itf = itf ? itf : &hook_xreq_default_itf;
+       hook->closure = closure;
 
-       TRACE_REQ_(addref, tr);
-       hook_req_addref(tr);
+       /* record the hook */
+       pthread_rwlock_wrlock(&rwlock);
+       hook->next = list_of_xreq_hooks;
+       list_of_xreq_hooks = hook;
+       pthread_rwlock_unlock(&rwlock);
+
+       /* returns it */
+       return hook;
 }
 
-static void req_hook_unref(void *closure)
+struct afb_hook_xreq *afb_hook_addref_xreq(struct afb_hook_xreq *hook)
 {
-       struct afb_hook_req *tr = closure;
-
-       TRACE_REQ_(unref, tr);
-       hook_req_unref(tr);
+       pthread_rwlock_wrlock(&rwlock);
+       hook->refcount++;
+       pthread_rwlock_unlock(&rwlock);
+       return hook;
 }
 
-static void req_hook_session_close(void *closure)
+void afb_hook_unref_xreq(struct afb_hook_xreq *hook)
 {
-       struct afb_hook_req *tr = closure;
+       struct afb_hook_xreq **prv;
 
-       TRACE_REQ_(session_close, tr);
-       afb_req_session_close(tr->req);
+       if (hook) {
+               pthread_rwlock_wrlock(&rwlock);
+               if (--hook->refcount)
+                       hook = NULL;
+               else {
+                       /* unlink */
+                       prv = &list_of_xreq_hooks;
+                       while (*prv && *prv != hook)
+                               prv = &(*prv)->next;
+                       if(*prv)
+                               *prv = hook->next;
+               }
+               pthread_rwlock_unlock(&rwlock);
+               if (hook) {
+                       /* free */
+                       free(hook->api);
+                       free(hook->verb);
+                       if (hook->session)
+                               afb_session_unref(hook->session);
+                       free(hook);
+               }
+       }
 }
 
-static int req_hook_session_set_LOA(void *closure, unsigned level)
+/******************************************************************************
+ * section: default callbacks for tracing daemon interface
+ *****************************************************************************/
+
+static void _hook_ditf_(const struct afb_ditf *ditf, const char *format, ...)
 {
-       struct afb_hook_req *tr = closure;
-       int r;
+       int len;
+       char *buffer;
+       va_list ap;
 
-       r = afb_req_session_set_LOA(tr->req, level);
-       TRACE_REQ(session_set_LOA, tr, level, r);
-       return r;
+       va_start(ap, format);
+       len = vasprintf(&buffer, format, ap);
+       va_end(ap);
+
+       if (len < 0)
+               NOTICE("hook ditf-%s allocation error for %s", ditf->prefix, format);
+       else {
+               NOTICE("hook ditf-%s %s", ditf->prefix, buffer);
+               free(buffer);
+       }
 }
 
-static int req_hook_subscribe(void *closure, struct afb_event event)
+static void hook_ditf_event_broadcast_before_cb(void *closure, const struct afb_ditf *ditf, const char *name, struct json_object *object)
 {
-       struct afb_hook_req *tr = closure;
-       int r;
+       _hook_ditf_(ditf, "event_broadcast.before(%s, %s)....", name, json_object_to_json_string(object));
+}
 
-       r = afb_req_subscribe(tr->req, event);
-       TRACE_REQ(subscribe, tr, event, r);
-       return r;
+static void hook_ditf_event_broadcast_after_cb(void *closure, const struct afb_ditf *ditf, const char *name, struct json_object *object, int result)
+{
+       _hook_ditf_(ditf, "event_broadcast.after(%s, %s) -> %d", name, json_object_to_json_string(object), result);
 }
 
-static int req_hook_unsubscribe(void *closure, struct afb_event event)
+static void hook_ditf_get_event_loop_cb(void *closure, const struct afb_ditf *ditf, struct sd_event *result)
 {
-       struct afb_hook_req *tr = closure;
-       int r;
+       _hook_ditf_(ditf, "get_event_loop() -> %p", result);
+}
 
-       r = afb_req_unsubscribe(tr->req, event);
-       TRACE_REQ(unsubscribe, tr, event, r);
-       return r;
+static void hook_ditf_get_user_bus_cb(void *closure, const struct afb_ditf *ditf, struct sd_bus *result)
+{
+       _hook_ditf_(ditf, "get_user_bus() -> %p", result);
 }
 
-static void req_hook_subcall_result(void *closure, int status, struct json_object *result)
+static void hook_ditf_get_system_bus_cb(void *closure, const struct afb_ditf *ditf, struct sd_bus *result)
 {
-       struct hook_subcall *sc = closure;
-       struct hook_subcall s = *sc;
+       _hook_ditf_(ditf, "get_system_bus() -> %p", result);
+}
+
+static void hook_ditf_vverbose_cb(void*closure, const struct afb_ditf *ditf, int level, const char *file, int line, const char *function, const char *fmt, va_list args)
+{
+       int len;
+       char *msg;
+       va_list ap;
+
+       va_copy(ap, args);
+       len = vasprintf(&msg, fmt, ap);
+       va_end(ap);
+
+       if (len < 0)
+               _hook_ditf_(ditf, "vverbose(%d, %s, %d, %s) -> %s ? ? ?", level, file, line, function, fmt);
+       else {
+               _hook_ditf_(ditf, "vverbose(%d, %s, %d, %s) -> %s", level, file, line, function, msg);
+               free(msg);
+       }
+}
 
-       free(sc);
-       TRACE_REQ(subcall_result, s.tr, status, result);
-       hook_req_unref(s.tr);
-       s.callback(s.cb_closure, status, result);
+static void hook_ditf_event_make_cb(void *closure, const struct afb_ditf *ditf, const char *name, struct afb_event result)
+{
+       _hook_ditf_(ditf, "event_make(%s) -> %s:%p", name, afb_event_name(result), result.closure);
 }
 
-static void req_hook_subcall(void *closure, const char *api, const char *verb, struct json_object *args, void (*callback)(void*, int, struct json_object*), void *cb_closure)
+static void hook_ditf_rootdir_get_fd_cb(void *closure, const struct afb_ditf *ditf, int result)
 {
-       struct afb_hook_req *tr = closure;
-       struct hook_subcall *sc;
+       char path[PATH_MAX];
+       if (result < 0)
+               _hook_ditf_(ditf, "rootdir_get_fd() -> %d, %m", result);
+       else {
+               sprintf(path, "/proc/self/fd/%d", result);
+               readlink(path, path, sizeof path);
+               _hook_ditf_(ditf, "rootdir_get_fd() -> %d = %s", result, path);
+       }
+}
 
-       TRACE_REQ(subcall, tr, api, verb, args);
-       sc = malloc(sizeof *sc);
-       if (sc) {
-               sc->tr = tr;
-               sc->callback = callback;
-               sc->cb_closure = cb_closure;
-               hook_req_addref(tr);
-               cb_closure = sc;
-               callback = req_hook_subcall_result;
+static void hook_ditf_rootdir_open_locale_cb(void *closure, const struct afb_ditf *ditf, const char *filename, int flags, const char *locale, int result)
+{
+       char path[PATH_MAX];
+       if (!locale)
+               locale = "(null)";
+       if (result < 0)
+               _hook_ditf_(ditf, "rootdir_open_locale(%s, %d, %s) -> %d, %m", filename, flags, locale, result);
+       else {
+               sprintf(path, "/proc/self/fd/%d", result);
+               readlink(path, path, sizeof path);
+               _hook_ditf_(ditf, "rootdir_open_locale(%s, %d, %s) -> %d = %s", filename, flags, locale, result, path);
        }
-       afb_req_subcall(tr->req, api, verb, args, callback, cb_closure);
-}
-
-static struct afb_req_itf req_hook_itf = {
-       .json = req_hook_json,
-       .get = req_hook_get,
-       .success = req_hook_success,
-       .fail = req_hook_fail,
-       .raw = req_hook_raw,
-       .send = req_hook_send,
-       .context_get = req_hook_context_get,
-       .context_set = req_hook_context_set,
-       .addref = req_hook_addref,
-       .unref = req_hook_unref,
-       .session_close = req_hook_session_close,
-       .session_set_LOA = req_hook_session_set_LOA,
-       .subscribe = req_hook_subscribe,
-       .unsubscribe = req_hook_unsubscribe,
-       .subcall = req_hook_subcall
+}
+
+
+static struct afb_hook_ditf_itf hook_ditf_default_itf = {
+       .hook_ditf_event_broadcast_before = hook_ditf_event_broadcast_before_cb,
+       .hook_ditf_event_broadcast_after = hook_ditf_event_broadcast_after_cb,
+       .hook_ditf_get_event_loop = hook_ditf_get_event_loop_cb,
+       .hook_ditf_get_user_bus = hook_ditf_get_user_bus_cb,
+       .hook_ditf_get_system_bus = hook_ditf_get_system_bus_cb,
+       .hook_ditf_vverbose = hook_ditf_vverbose_cb,
+       .hook_ditf_event_make = hook_ditf_event_make_cb,
+       .hook_ditf_rootdir_get_fd = hook_ditf_rootdir_get_fd_cb,
+       .hook_ditf_rootdir_open_locale = hook_ditf_rootdir_open_locale_cb,
 };
 
+/******************************************************************************
+ * section: hooks for tracing requests
+ *****************************************************************************/
+
+#define _HOOK_DITF_(what,...)   \
+       struct afb_hook_ditf *hook; \
+       pthread_rwlock_rdlock(&rwlock); \
+       hook = list_of_ditf_hooks; \
+       while (hook) { \
+               if (hook->itf->hook_ditf_##what \
+                && (hook->flags & afb_hook_flag_ditf_##what) != 0 \
+                && (!hook->api || !strcasecmp(hook->api, ditf->prefix))) { \
+                       hook->itf->hook_ditf_##what(hook->closure, __VA_ARGS__); \
+               } \
+               hook = hook->next; \
+       } \
+       pthread_rwlock_unlock(&rwlock);
+
+void afb_hook_ditf_event_broadcast_before(const struct afb_ditf *ditf, const char *name, struct json_object *object)
+{
+       _HOOK_DITF_(event_broadcast_before, ditf, name, object);
+}
+
+int afb_hook_ditf_event_broadcast_after(const struct afb_ditf *ditf, const char *name, struct json_object *object, int result)
+{
+       _HOOK_DITF_(event_broadcast_after, ditf, name, object, result);
+       return result;
+}
+
+struct sd_event *afb_hook_ditf_get_event_loop(const struct afb_ditf *ditf, struct sd_event *result)
+{
+       _HOOK_DITF_(get_event_loop, ditf, result);
+       return result;
+}
+
+struct sd_bus *afb_hook_ditf_get_user_bus(const struct afb_ditf *ditf, struct sd_bus *result)
+{
+       _HOOK_DITF_(get_user_bus, ditf, result);
+       return result;
+}
+
+struct sd_bus *afb_hook_ditf_get_system_bus(const struct afb_ditf *ditf, struct sd_bus *result)
+{
+       _HOOK_DITF_(get_system_bus, ditf, result);
+       return result;
+}
+
+void afb_hook_ditf_vverbose(const struct afb_ditf *ditf, int level, const char *file, int line, const char *function, const char *fmt, va_list args)
+{
+       _HOOK_DITF_(vverbose, ditf, level, file, line, function, fmt, args);
+}
+
+struct afb_event afb_hook_ditf_event_make(const struct afb_ditf *ditf, const char *name, struct afb_event result)
+{
+       _HOOK_DITF_(event_make, ditf, name, result);
+       return result;
+}
+
+int afb_hook_ditf_rootdir_get_fd(const struct afb_ditf *ditf, int result)
+{
+       _HOOK_DITF_(rootdir_get_fd, ditf, result);
+       return result;
+}
+
+int afb_hook_ditf_rootdir_open_locale(const struct afb_ditf *ditf, const char *filename, int flags, const char *locale, int result)
+{
+       _HOOK_DITF_(rootdir_open_locale, ditf, filename, flags, locale, result);
+       return result;
+}
+
+
+
 /******************************************************************************
  * section: 
  *****************************************************************************/
 
-struct afb_req afb_hook_req_call(struct afb_req req, struct afb_context *context, const char *api, const char *verb)
+int afb_hook_flags_ditf(const char *api)
 {
-       int add;
-       struct afb_hook_req *tr;
-       struct afb_hook *hook;
+       int flags;
+       struct afb_hook_ditf *hook;
 
-       hook = list_of_hooks;
-       if (hook) {
-               tr = NULL;
-               do {
-                       add = (hook->flags & afb_hook_flags_req_all) != 0
-                          && (!hook->session || hook->session == context->session)
-                          && (!hook->api || !strcasecmp(hook->api, api))
-                          && (!hook->verb || !strcasecmp(hook->verb, verb));
-                       if (add) {
-                               if (!tr)
-                                       tr = hook_req_create(req, context, api, verb);
-                               if (tr)
-                                       hook_req_add_observer(tr, hook);
-                       }
-                       hook = hook->next;
-               } while(hook);
-               if (tr) {
-                       req.closure = tr;
-                       req.itf = &req_hook_itf;
-                       TRACE_REQX(begin, tr);
-               }
+       pthread_rwlock_rdlock(&rwlock);
+       flags = 0;
+       hook = list_of_ditf_hooks;
+       while (hook) {
+               if (!api || !hook->api || !strcasecmp(hook->api, api))
+                       flags |= hook->flags;
+               hook = hook->next;
        }
-
-       return req;
+       pthread_rwlock_unlock(&rwlock);
+       return flags;
 }
 
-struct afb_hook *afb_hook_req_create(const char *api, const char *verb, struct afb_session *session, unsigned flags, struct afb_hook_req_itf *itf, void *closure)
+struct afb_hook_ditf *afb_hook_create_ditf(const char *api, int flags, struct afb_hook_ditf_itf *itf, void *closure)
 {
-       struct afb_hook *hook;
+       struct afb_hook_ditf *hook;
 
-       hook = malloc(sizeof *hook);
+       /* alloc the result */
+       hook = calloc(1, sizeof *hook);
        if (hook == NULL)
                return NULL;
 
+       /* get a copy of the names */
        hook->api = api ? strdup(api) : NULL;
-       hook->verb = verb ? strdup(verb) : NULL;
-       hook->session = session ? afb_session_addref(session) : NULL;
-
-       if ((api && !hook->api) || (verb && !hook->verb)) {
-               free(hook->api);
-               free(hook->verb);
-               if (hook->session)
-                       afb_session_unref(hook->session);
+       if (api && !hook->api) {
                free(hook);
                return NULL;
        }
 
+       /* initialise the rest */
        hook->refcount = 1;
        hook->flags = flags;
-       hook->reqitf = itf ? itf : &hook_req_default_itf;
+       hook->itf = itf ? itf : &hook_ditf_default_itf;
        hook->closure = closure;
 
-       hook->next = list_of_hooks;
-       list_of_hooks = hook;
+       /* record the hook */
+       pthread_rwlock_wrlock(&rwlock);
+       hook->next = list_of_ditf_hooks;
+       list_of_ditf_hooks = hook;
+       pthread_rwlock_unlock(&rwlock);
+
+       /* returns it */
        return hook;
 }
 
-struct afb_hook *afb_hook_addref(struct afb_hook *hook)
+struct afb_hook_ditf *afb_hook_addref_ditf(struct afb_hook_ditf *hook)
 {
+       pthread_rwlock_wrlock(&rwlock);
        hook->refcount++;
+       pthread_rwlock_unlock(&rwlock);
        return hook;
 }
 
-void afb_hook_unref(struct afb_hook *hook)
+void afb_hook_unref_ditf(struct afb_hook_ditf *hook)
 {
-       if (!--hook->refcount) {
-               /* unlink */
-               struct afb_hook **prv = &list_of_hooks;
-               while (*prv && *prv != hook)
-                       prv = &(*prv)->next;
-               if(*prv)
-                       *prv = hook->next;
+       struct afb_hook_ditf **prv;
 
-               /* free */
-               free(hook->api);
-               free(hook->verb);
-               if (hook->session)
-                       afb_session_unref(hook->session);
-               free(hook);
+       if (hook) {
+               pthread_rwlock_wrlock(&rwlock);
+               if (--hook->refcount)
+                       hook = NULL;
+               else {
+                       /* unlink */
+                       prv = &list_of_ditf_hooks;
+                       while (*prv && *prv != hook)
+                               prv = &(*prv)->next;
+                       if(*prv)
+                               *prv = hook->next;
+               }
+               pthread_rwlock_unlock(&rwlock);
+               if (hook) {
+                       /* free */
+                       free(hook->api);
+                       free(hook);
+               }
        }
 }