Add logging by request
[src/app-framework-binder.git] / src / afb-hook.c
index bafbbe9..6afcd2f 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-cred.h"
 #include "afb-xreq.h"
+#include "afb-ditf.h"
+#include "afb-svc.h"
 #include "verbose.h"
 
 /**
- * Definition of a hook
+ * Definition of a hook for xreq
  */
-struct afb_hook {
-       struct afb_hook *next; /**< next hook */
+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 *reqitf; /**< interface of hook */
+       struct afb_hook_xreq_itf *itf; /**< interface of hook */
        void *closure; /**< closure for callbacks */
 };
 
-/*
- * Structure for handling subcalls callbacks
+/**
+ * Definition of a hook for ditf
  */
-struct hook_subcall {
-       struct afb_xreq *xreq; /* hookd request */
-       void (*callback)(void*, int, struct json_object*); /* client callback */
-       void *cb_closure; /* cient closure */
+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 */
+};
+
+/**
+ * Definition of a hook for svc
+ */
+struct afb_hook_svc {
+       struct afb_hook_svc *next; /**< next hook */
+       unsigned refcount; /**< reference count */
+       char *api; /**< api hooked or NULL for any */
+       unsigned flags; /**< hook flags */
+       struct afb_hook_svc_itf *itf; /**< interface of hook */
+       void *closure; /**< closure for callbacks */
 };
 
 /* synchronisation across threads */
 static pthread_rwlock_t rwlock = PTHREAD_RWLOCK_INITIALIZER;
 
-/* list of hooks */
-static struct afb_hook *list_of_hooks = NULL;
+/* list of hooks for xreq */
+static struct afb_hook_xreq *list_of_xreq_hooks = NULL;
+
+/* list of hooks for ditf */
+static struct afb_hook_ditf *list_of_ditf_hooks = NULL;
+
+/* list of hooks for svc */
+static struct afb_hook_svc *list_of_svc_hooks = NULL;
 
 /******************************************************************************
  * section: default callbacks for tracing requests
@@ -86,7 +112,17 @@ static void _hook_xreq_(const struct afb_xreq *xreq, const char *format, ...)
 
 static void hook_xreq_begin_default_cb(void * closure, const struct afb_xreq *xreq)
 {
-       _hook_xreq_(xreq, "BEGIN");
+       if (!xreq->cred)
+               _hook_xreq_(xreq, "BEGIN");
+       else
+               _hook_xreq_(xreq, "BEGIN uid=%d=%s gid=%d pid=%d label=%s id=%s",
+                       (int)xreq->cred->uid,
+                       xreq->cred->user,
+                       (int)xreq->cred->gid,
+                       (int)xreq->cred->pid,
+                       xreq->cred->label?:"(null)",
+                       xreq->cred->id?:"(null)"
+               );
 }
 
 static void hook_xreq_end_default_cb(void * closure, const struct afb_xreq *xreq)
@@ -114,16 +150,6 @@ static void hook_xreq_fail_default_cb(void * closure, const struct afb_xreq *xre
        _hook_xreq_(xreq, "fail(%s, %s)", status, info);
 }
 
-static void hook_xreq_raw_default_cb(void * closure, const struct afb_xreq *xreq, const char *buffer, size_t size)
-{
-       _hook_xreq_(xreq, "raw() -> %.*s", (int)size, buffer);
-}
-
-static void hook_xreq_send_default_cb(void * closure, const struct afb_xreq *xreq, const char *buffer, size_t size)
-{
-       _hook_xreq_(xreq, "send(%.*s)", (int)size, buffer);
-}
-
 static void hook_xreq_context_get_default_cb(void * closure, const struct afb_xreq *xreq, void *value)
 {
        _hook_xreq_(xreq, "context_get() -> %p", value);
@@ -184,6 +210,24 @@ static void hook_xreq_subcallsync_result_default_cb(void * closure, const struct
        _hook_xreq_(xreq, "    ...subcallsync... -> %d: %s", status, json_object_to_json_string(result));
 }
 
+static void hook_xreq_vverbose_default_cb(void * closure, const struct afb_xreq *xreq, int level, const char *file, int line, const char *func, 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_xreq_(xreq, "vverbose(%d, %s, %d, %s) -> %s ? ? ?", level, file, line, func, fmt);
+       else {
+               _hook_xreq_(xreq, "vverbose(%d, %s, %d, %s) -> %s", level, file, line, func, msg);
+               free(msg);
+       }
+}
+
 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,
@@ -191,8 +235,6 @@ static struct afb_hook_xreq_itf hook_xreq_default_itf = {
        .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,
@@ -205,6 +247,7 @@ static struct afb_hook_xreq_itf hook_xreq_default_itf = {
        .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,
+       .hook_xreq_vverbose = hook_xreq_vverbose_default_cb
 };
 
 /******************************************************************************
@@ -212,16 +255,16 @@ static struct afb_hook_xreq_itf hook_xreq_default_itf = {
  *****************************************************************************/
 
 #define _HOOK_XREQ_(what,...)   \
-       struct afb_hook *hook; \
+       struct afb_hook_xreq *hook; \
        pthread_rwlock_rdlock(&rwlock); \
-       hook = list_of_hooks; \
+       hook = list_of_xreq_hooks; \
        while (hook) { \
-               if (hook->reqitf->hook_xreq_##what \
+               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->reqitf->hook_xreq_##what(hook->closure, __VA_ARGS__); \
+                       hook->itf->hook_xreq_##what(hook->closure, __VA_ARGS__); \
                } \
                hook = hook->next; \
        } \
@@ -260,17 +303,6 @@ void afb_hook_xreq_fail(const struct afb_xreq *xreq, const char *status, const c
        _HOOK_XREQ_(fail, xreq, status, info);
 }
 
-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;
-}
-
-void afb_hook_xreq_send(const struct afb_xreq *xreq, const char *buffer, size_t size)
-{
-       _HOOK_XREQ_(send, xreq, buffer, size);
-}
-
 void *afb_hook_xreq_context_get(const struct afb_xreq *xreq, void *value)
 {
        _HOOK_XREQ_(context_get, xreq, value);
@@ -336,8 +368,13 @@ int afb_hook_xreq_subcallsync_result(const struct afb_xreq *xreq, int status, st
        return status;
 }
 
+void afb_hook_xreq_vverbose(const struct afb_xreq *xreq, int level, const char *file, int line, const char *func, const char *fmt, va_list args)
+{
+       _HOOK_XREQ_(vverbose, xreq, level, file ?: "?", line, func ?: "?", fmt, args);
+}
+
 /******************************************************************************
- * section: 
+ * section: hooking xreqs
  *****************************************************************************/
 
 void afb_hook_init_xreq(struct afb_xreq *xreq)
@@ -346,12 +383,12 @@ void afb_hook_init_xreq(struct afb_xreq *xreq)
 
        int f, flags;
        int add;
-       struct afb_hook *hook;
+       struct afb_hook_xreq *hook;
 
        /* scan hook list to get the expected flags */
        flags = 0;
        pthread_rwlock_rdlock(&rwlock);
-       hook = list_of_hooks;
+       hook = list_of_xreq_hooks;
        while (hook) {
                f = hook->flags & afb_hook_flags_req_all;
                add = f != 0
@@ -375,12 +412,12 @@ void afb_hook_init_xreq(struct afb_xreq *xreq)
        }
 }
 
-struct afb_hook *afb_hook_xreq_create(const char *api, const char *verb, struct afb_session *session, unsigned flags, struct afb_hook_xreq_itf *itf, 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 *hook;
+       struct afb_hook_xreq *hook;
 
        /* alloc the result */
-       hook = malloc(sizeof *hook);
+       hook = calloc(1, sizeof *hook);
        if (hook == NULL)
                return NULL;
 
@@ -400,20 +437,20 @@ struct afb_hook *afb_hook_xreq_create(const char *api, const char *verb, struct
                afb_session_addref(session);
        hook->refcount = 1;
        hook->flags = flags;
-       hook->reqitf = itf ? itf : &hook_xreq_default_itf;
+       hook->itf = itf ? itf : &hook_xreq_default_itf;
        hook->closure = closure;
 
        /* record the hook */
        pthread_rwlock_wrlock(&rwlock);
-       hook->next = list_of_hooks;
-       list_of_hooks = hook;
+       hook->next = list_of_xreq_hooks;
+       list_of_xreq_hooks = hook;
        pthread_rwlock_unlock(&rwlock);
 
        /* returns it */
        return hook;
 }
 
-struct afb_hook *afb_hook_addref(struct afb_hook *hook)
+struct afb_hook_xreq *afb_hook_addref_xreq(struct afb_hook_xreq *hook)
 {
        pthread_rwlock_wrlock(&rwlock);
        hook->refcount++;
@@ -421,9 +458,9 @@ struct afb_hook *afb_hook_addref(struct afb_hook *hook)
        return hook;
 }
 
-void afb_hook_unref(struct afb_hook *hook)
+void afb_hook_unref_xreq(struct afb_hook_xreq *hook)
 {
-       struct afb_hook **prv;
+       struct afb_hook_xreq **prv;
 
        if (hook) {
                pthread_rwlock_wrlock(&rwlock);
@@ -431,7 +468,7 @@ void afb_hook_unref(struct afb_hook *hook)
                        hook = NULL;
                else {
                        /* unlink */
-                       prv = &list_of_hooks;
+                       prv = &list_of_xreq_hooks;
                        while (*prv && *prv != hook)
                                prv = &(*prv)->next;
                        if(*prv)
@@ -449,3 +486,498 @@ void afb_hook_unref(struct afb_hook *hook)
        }
 }
 
+/******************************************************************************
+ * section: default callbacks for tracing daemon interface
+ *****************************************************************************/
+
+static void _hook_ditf_(const struct afb_ditf *ditf, const char *format, ...)
+{
+       int len;
+       char *buffer;
+       va_list ap;
+
+       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 void hook_ditf_event_broadcast_before_cb(void *closure, const struct afb_ditf *ditf, const char *name, struct json_object *object)
+{
+       _hook_ditf_(ditf, "event_broadcast.before(%s, %s)....", name, json_object_to_json_string(object));
+}
+
+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 void hook_ditf_get_event_loop_cb(void *closure, const struct afb_ditf *ditf, struct sd_event *result)
+{
+       _hook_ditf_(ditf, "get_event_loop() -> %p", result);
+}
+
+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 hook_ditf_get_system_bus_cb(void *closure, const struct afb_ditf *ditf, struct sd_bus *result)
+{
+       _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);
+       }
+}
+
+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 hook_ditf_rootdir_get_fd_cb(void *closure, const struct afb_ditf *ditf, int result)
+{
+       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);
+       }
+}
+
+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);
+       }
+}
+
+static void hook_ditf_queue_job(void *closure, const struct afb_ditf *ditf, void (*callback)(int signum, void *arg), void *argument, void *group, int timeout, int result)
+{
+       _hook_ditf_(ditf, "queue_job(%p, %p, %p, %d) -> %d", callback, argument, group, timeout, result);
+}
+
+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,
+       .hook_ditf_queue_job = hook_ditf_queue_job
+};
+
+/******************************************************************************
+ * section: hooks for tracing daemon interface (ditf)
+ *****************************************************************************/
+
+#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;
+}
+
+int afb_hook_ditf_queue_job(const struct afb_ditf *ditf, void (*callback)(int signum, void *arg), void *argument, void *group, int timeout, int result)
+{
+       _HOOK_DITF_(queue_job, ditf, callback, argument, group, timeout, result);
+       return result;
+}
+
+/******************************************************************************
+ * section: hooking ditf
+ *****************************************************************************/
+
+int afb_hook_flags_ditf(const char *api)
+{
+       int flags;
+       struct afb_hook_ditf *hook;
+
+       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;
+       }
+       pthread_rwlock_unlock(&rwlock);
+       return flags;
+}
+
+struct afb_hook_ditf *afb_hook_create_ditf(const char *api, int flags, struct afb_hook_ditf_itf *itf, void *closure)
+{
+       struct afb_hook_ditf *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;
+       if (api && !hook->api) {
+               free(hook);
+               return NULL;
+       }
+
+       /* initialise the rest */
+       hook->refcount = 1;
+       hook->flags = flags;
+       hook->itf = itf ? itf : &hook_ditf_default_itf;
+       hook->closure = closure;
+
+       /* 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_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_ditf(struct afb_hook_ditf *hook)
+{
+       struct afb_hook_ditf **prv;
+
+       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);
+               }
+       }
+}
+
+/******************************************************************************
+ * section: default callbacks for tracing service interface (svc)
+ *****************************************************************************/
+
+static void _hook_svc_(const struct afb_svc *svc, const char *format, ...)
+{
+       int len;
+       char *buffer;
+       va_list ap;
+
+       va_start(ap, format);
+       len = vasprintf(&buffer, format, ap);
+       va_end(ap);
+
+       if (len < 0)
+               NOTICE("hook svc-%s allocation error for %s", svc->api, format);
+       else {
+               NOTICE("hook svc-%s %s", svc->api, buffer);
+               free(buffer);
+       }
+}
+
+static void hook_svc_start_before_default_cb(void *closure, const struct afb_svc *svc)
+{
+       _hook_svc_(svc, "start.before");
+}
+
+static void hook_svc_start_after_default_cb(void *closure, const struct afb_svc *svc, int status)
+{
+       _hook_svc_(svc, "start.after -> %d", status);
+}
+
+static void hook_svc_on_event_before_default_cb(void *closure, const struct afb_svc *svc, const char *event, int eventid, struct json_object *object)
+{
+       _hook_svc_(svc, "on_event.before(%s, %d, %s)", event, eventid, json_object_to_json_string(object));
+}
+
+static void hook_svc_on_event_after_default_cb(void *closure, const struct afb_svc *svc, const char *event, int eventid, struct json_object *object)
+{
+       _hook_svc_(svc, "on_event.after(%s, %d, %s)", event, eventid, json_object_to_json_string(object));
+}
+
+static void hook_svc_call_default_cb(void *closure, const struct afb_svc *svc, const char *api, const char *verb, struct json_object *args)
+{
+       _hook_svc_(svc, "call(%s/%s, %s) ...", api, verb, json_object_to_json_string(args));
+}
+
+static void hook_svc_call_result_default_cb(void *closure, const struct afb_svc *svc, int status, struct json_object *result)
+{
+       _hook_svc_(svc, "    ...call... -> %d: %s", status, json_object_to_json_string(result));
+}
+
+static void hook_svc_callsync_default_cb(void *closure, const struct afb_svc *svc, const char *api, const char *verb, struct json_object *args)
+{
+       _hook_svc_(svc, "callsync(%s/%s, %s) ...", api, verb, json_object_to_json_string(args));
+}
+
+static void hook_svc_callsync_result_default_cb(void *closure, const struct afb_svc *svc, int status, struct json_object *result)
+{
+       _hook_svc_(svc, "    ...callsync... -> %d: %s", status, json_object_to_json_string(result));
+}
+
+static struct afb_hook_svc_itf hook_svc_default_itf = {
+       .hook_svc_start_before = hook_svc_start_before_default_cb,
+       .hook_svc_start_after = hook_svc_start_after_default_cb,
+       .hook_svc_on_event_before = hook_svc_on_event_before_default_cb,
+       .hook_svc_on_event_after = hook_svc_on_event_after_default_cb,
+       .hook_svc_call = hook_svc_call_default_cb,
+       .hook_svc_call_result = hook_svc_call_result_default_cb,
+       .hook_svc_callsync = hook_svc_callsync_default_cb,
+       .hook_svc_callsync_result = hook_svc_callsync_result_default_cb
+};
+
+/******************************************************************************
+ * section: hooks for tracing service interface (svc)
+ *****************************************************************************/
+
+#define _HOOK_SVC_(what,...)   \
+       struct afb_hook_svc *hook; \
+       pthread_rwlock_rdlock(&rwlock); \
+       hook = list_of_svc_hooks; \
+       while (hook) { \
+               if (hook->itf->hook_svc_##what \
+                && (hook->flags & afb_hook_flag_svc_##what) != 0 \
+                && (!hook->api || !strcasecmp(hook->api, svc->api))) { \
+                       hook->itf->hook_svc_##what(hook->closure, __VA_ARGS__); \
+               } \
+               hook = hook->next; \
+       } \
+       pthread_rwlock_unlock(&rwlock);
+
+void afb_hook_svc_start_before(const struct afb_svc *svc)
+{
+       _HOOK_SVC_(start_before, svc);
+}
+
+int afb_hook_svc_start_after(const struct afb_svc *svc, int status)
+{
+       _HOOK_SVC_(start_after, svc, status);
+       return status;
+}
+
+void afb_hook_svc_on_event_before(const struct afb_svc *svc, const char *event, int eventid, struct json_object *object)
+{
+       _HOOK_SVC_(on_event_before, svc, event, eventid, object);
+}
+
+void afb_hook_svc_on_event_after(const struct afb_svc *svc, const char *event, int eventid, struct json_object *object)
+{
+       _HOOK_SVC_(on_event_after, svc, event, eventid, object);
+}
+
+void afb_hook_svc_call(const struct afb_svc *svc, const char *api, const char *verb, struct json_object *args)
+{
+       _HOOK_SVC_(call, svc, api, verb, args);
+}
+
+void afb_hook_svc_call_result(const struct afb_svc *svc, int status, struct json_object *result)
+{
+       _HOOK_SVC_(call_result, svc, status, result);
+}
+
+void afb_hook_svc_callsync(const struct afb_svc *svc, const char *api, const char *verb, struct json_object *args)
+{
+       _HOOK_SVC_(callsync, svc, api, verb, args);
+}
+
+int afb_hook_svc_callsync_result(const struct afb_svc *svc, int status, struct json_object *result)
+{
+       _HOOK_SVC_(callsync_result, svc, status, result);
+       return status;
+}
+
+/******************************************************************************
+ * section: hooking services (svc)
+ *****************************************************************************/
+
+int afb_hook_flags_svc(const char *api)
+{
+       int flags;
+       struct afb_hook_svc *hook;
+
+       pthread_rwlock_rdlock(&rwlock);
+       flags = 0;
+       hook = list_of_svc_hooks;
+       while (hook) {
+               if (!api || !hook->api || !strcasecmp(hook->api, api))
+                       flags |= hook->flags;
+               hook = hook->next;
+       }
+       pthread_rwlock_unlock(&rwlock);
+       return flags;
+}
+
+struct afb_hook_svc *afb_hook_create_svc(const char *api, int flags, struct afb_hook_svc_itf *itf, void *closure)
+{
+       struct afb_hook_svc *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;
+       if (api && !hook->api) {
+               free(hook);
+               return NULL;
+       }
+
+       /* initialise the rest */
+       hook->refcount = 1;
+       hook->flags = flags;
+       hook->itf = itf ? itf : &hook_svc_default_itf;
+       hook->closure = closure;
+
+       /* record the hook */
+       pthread_rwlock_wrlock(&rwlock);
+       hook->next = list_of_svc_hooks;
+       list_of_svc_hooks = hook;
+       pthread_rwlock_unlock(&rwlock);
+
+       /* returns it */
+       return hook;
+}
+
+struct afb_hook_svc *afb_hook_addref_svc(struct afb_hook_svc *hook)
+{
+       pthread_rwlock_wrlock(&rwlock);
+       hook->refcount++;
+       pthread_rwlock_unlock(&rwlock);
+       return hook;
+}
+
+void afb_hook_unref_svc(struct afb_hook_svc *hook)
+{
+       struct afb_hook_svc **prv;
+
+       if (hook) {
+               pthread_rwlock_wrlock(&rwlock);
+               if (--hook->refcount)
+                       hook = NULL;
+               else {
+                       /* unlink */
+                       prv = &list_of_svc_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);
+               }
+       }
+}
+