5 files changed, 68 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index c895ba7..213f196 100644
--- a/Makefile
+++ b/Makefile
@@ -19,7 +19,7 @@ trace-read.o::		parse-events.h
 trace-cmd.o::           parse-events.h $(LIB_FILE)
 
 trace-cmd:: trace-cmd.o trace-read.o trace-util.o
-        $(CC) $^ $(LIBS) -o $@
+        $(CC) $^ $(LIBS) -rdynamic -o $@
 
 parse-events.o: parse-events.c parse-events.h
         $(CC) -c $(CFLAGS) $(EXT) $(INCLUDES) -fPIC $< -o $@
diff --git a/parse-events.c b/parse-events.c
index 5f02519..15cd0e4 100644
--- a/parse-events.c
+++ b/parse-events.c
@@ -2180,6 +2180,22 @@ static struct event *trace_find_event(int id)
         return event;
 }
 
+static struct event *
+trace_find_event_by_name(const char *sys, const char *name)
+{
+        struct event *event;
+
+        for (event = event_list; event; event = event->next) {
+                if (strcmp(event->name, name) == 0) {
+                        if (!sys)
+                                break;
+                        if (strcmp(event->system, sys) == 0)
+                                break;
+                }
+        }
+        return event;
+}
+
 static unsigned long long eval_num_arg(void *data, int size,
                                    struct event *event, struct print_arg *arg)
 {
@@ -3236,7 +3252,10 @@ void pevent_print_event(struct trace_seq *s,
                 return;
         }
 
-        pretty_print(s, data, size, event);
+        if (event->handler)
+                event->handler(s, data, size);
+        else
+                pretty_print(s, data, size, event);
         trace_seq_putc(s, '\n');
 }
 
@@ -3488,6 +3507,30 @@ int pevent_parse_event(char *buf, unsigned long size, char *sys)
         return -1;
 }
 
+int pevent_register_event_handler(int id, char *sys_name, char *event_name,
+                                  pevent_event_handler_func func)
+{
+        struct event *event;
+
+        if (id >= 0) {
+                /* search by id */
+                event = trace_find_event(id);
+                if (!event)
+                        return -1;
+                if (event_name && (strcmp(event_name, event->name) != 0))
+                        return -1;
+                if (sys_name && (strcmp(sys_name, event->system) != 0))
+                        return -1;
+        } else {
+                event = trace_find_event_by_name(sys_name, event_name);
+                if (!event)
+                        return -1;
+        }
+
+        event->handler = func;
+        return 0;
+}
+
 void parse_set_info(int nr_cpus, int long_sz)
 {
         cpus = nr_cpus;
diff --git a/parse-events.h b/parse-events.h
index ceffef2..b4e7fdf 100644
--- a/parse-events.h
+++ b/parse-events.h
@@ -46,6 +46,8 @@ extern int trace_seq_do_printf(struct trace_seq *s);
 /* ----------------------- pevent ----------------------- */
 
 typedef int (*pevent_plugin_load_func)(void);
+typedef int (*pevent_event_handler_func)(struct trace_seq *s, void *data, int size);
+
 #define PEVENT_PLUGIN_LOADER pevent_plugin_loader
 #define MAKE_STR(x) #x
 #define PEVENT_PLUGIN_LOADER_NAME MAKE_STR(pevent_plugin_loader)
@@ -173,6 +175,7 @@ struct event {
         struct format           format;
         struct print_fmt        print_fmt;
         char                    *system;
+        pevent_event_handler_func handler;
 };
 
 enum {
@@ -288,6 +291,9 @@ int pevent_parse_header_page(char *buf, unsigned long size);
 
 int pevent_parse_event(char *buf, unsigned long size, char *sys);
 
+int pevent_register_event_handler(int id, char *sys_name, char *event_name,
+                                  pevent_event_handler_func func);
+
 /* for debugging */
 void pevent_print_funcs(void);
 void pevent_print_printk(void);
diff --git a/test_plugin.c b/test_plugin.c
index fd62c27..26edbad 100644
--- a/test_plugin.c
+++ b/test_plugin.c
@@ -4,8 +4,21 @@
 
 #include "parse-events.h"
 
+static int handler(struct trace_seq *s, void *data, int size)
+{
+        int ret;
+
+        ret = trace_seq_printf(s, "COMM: %s state is %d next is %s",
+                               (char *)(data+12), *(int *)(data + 40),
+                               (char *)(data+48));
+        return ret;
+}
+
 int PEVENT_PLUGIN_LOADER(void)
 {
         printf("HELLO WORLD!!!\n");
+
+        pevent_register_event_handler(-1, "sched", "sched_switch",
+                                      handler);
         return 0;
 }
diff --git a/trace-util.c b/trace-util.c
index b60b680..4780f26 100644
--- a/trace-util.c
+++ b/trace-util.c
@@ -96,14 +96,15 @@ static int load_plugin(const char *path, const char *file)
 
         handle = dlopen(plugin, RTLD_NOW);
         if (!handle) {
-                warning("cound not load plugin '%s'", plugin);
+                warning("cound not load plugin '%s'\n%s\n",
+                        plugin, dlerror());
                 return -1;
         }
 
         func = dlsym(handle, PEVENT_PLUGIN_LOADER_NAME);
         if (!func) {
-                warning("cound not find func '%s' in plugin '%s'",
-                        PEVENT_PLUGIN_LOADER_NAME, plugin);
+                warning("cound not find func '%s' in plugin '%s'\n%s\n",
+                        PEVENT_PLUGIN_LOADER_NAME, plugin, dlerror());
                 return -1;
         }