trace-cmd: Unload plugins on tracecmd_close()

When the handle is freed, we need to unload the plugins, otherwise
we will keep loading them if an app closes and opens a new handle.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

4 files changed, 49 insertions, 14 deletions

diff --git a/parse-events.h b/parse-events.h
index e148e7f..1866299 100644
--- a/parse-events.h
+++ b/parse-events.h
@@ -67,10 +67,14 @@ typedef int (*pevent_event_handler_func)(struct trace_seq *s,
                                          struct event_format *event);
 
 typedef int (*pevent_plugin_load_func)(struct pevent *pevent);
+typedef int (*pevent_plugin_unload_func)(void);
 
 #define PEVENT_PLUGIN_LOADER pevent_plugin_loader
-#define MAKE_STR(x) #x
-#define PEVENT_PLUGIN_LOADER_NAME MAKE_STR(pevent_plugin_loader)
+#define PEVENT_PLUGIN_UNLOADER pevent_plugin_unloader
+#define _MAKE_STR(x)    #x
+#define MAKE_STR(x)     _MAKE_STR(x)
+#define PEVENT_PLUGIN_LOADER_NAME MAKE_STR(PEVENT_PLUGIN_LOADER)
+#define PEVENT_PLUGIN_UNLOADER_NAME MAKE_STR(PEVENT_PLUGIN_UNLOADER)
 
 #define NSECS_PER_SEC           1000000000ULL
 #define NSECS_PER_USEC          1000ULL
diff --git a/trace-cmd.h b/trace-cmd.h
index 98b4dec..eda7181 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -8,7 +8,9 @@ void parse_cmdlines(struct pevent *pevent, char *file, int size);
 void parse_proc_kallsyms(struct pevent *pevent, char *file, unsigned int size);
 void parse_ftrace_printk(char *file, unsigned int size);
 
-int trace_load_plugins(struct pevent *pevent);
+struct plugin_list;
+struct plugin_list *tracecmd_load_plugins(struct pevent *pevent);
+void tracecmd_unload_plugins(struct plugin_list *list);
 
 enum {
         RINGBUF_TYPE_PADDING            = 29,
diff --git a/trace-input.c b/trace-input.c
index 0f2f7d8..af15634 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -47,6 +47,7 @@ struct cpu_data {
 
 struct tracecmd_input {
         struct pevent           *pevent;
+        struct plugin_list      *plugin_list;
         int                     fd;
         int                     long_size;
         int                     page_size;
@@ -456,7 +457,7 @@ int tracecmd_read_headers(struct tracecmd_input *handle)
         /* register default ftrace functions first */
         tracecmd_ftrace_overrides(handle);
 
-        trace_load_plugins(pevent);
+        handle->plugin_list = tracecmd_load_plugins(pevent);
 
         return 0;
 }
@@ -1711,6 +1712,7 @@ void tracecmd_close(struct tracecmd_input *handle)
 
         close(handle->fd);
         pevent_free(handle->pevent);
+        tracecmd_unload_plugins(handle->plugin_list);
         free(handle);
 }
 
diff --git a/trace-util.c b/trace-util.c
index 7a75056..7d168f9 100644
--- a/trace-util.c
+++ b/trace-util.c
@@ -22,6 +22,11 @@
 # define MAX_PATH 1024
 #endif
 
+struct plugin_list {
+        struct plugin_list      *next;
+        void                    *handle;
+};
+
 void __weak die(char *fmt, ...)
 {
         va_list ap;
@@ -148,12 +153,14 @@ void parse_ftrace_printk(char *file, unsigned int size __unused)
         }
 }
 
-static int load_plugin(struct pevent *pevent,
-                       const char *path, const char *file)
+static struct plugin_list *
+load_plugin(struct pevent *pevent, struct plugin_list *plugin_list,
+            const char *path, const char *file)
 {
+        pevent_plugin_load_func func;
+        struct plugin_list *list;
         char *plugin;
         void *handle;
-        pevent_plugin_load_func func;
         int ret = -1;
 
         plugin = malloc_or_die(strlen(path) + strlen(file) + 2);
@@ -169,6 +176,11 @@ static int load_plugin(struct pevent *pevent,
                 goto out;
         }
 
+        list = malloc_or_die(sizeof(*list));
+        list->next = plugin_list;
+        list->handle = handle;
+        plugin_list = list;
+
         func = dlsym(handle, PEVENT_PLUGIN_LOADER_NAME);
         if (!func) {
                 warning("cound not find func '%s' in plugin '%s'\n%s\n",
@@ -182,8 +194,7 @@ static int load_plugin(struct pevent *pevent,
  out:
         free(plugin);
 
-        /* dlclose ?? */
-        return ret;
+        return plugin_list;
 }
 
 char *tracecmd_find_tracing_dir(void)
@@ -221,8 +232,9 @@ char *tracecmd_find_tracing_dir(void)
         return tracing_dir;
 }
 
-int trace_load_plugins(struct pevent *pevent)
+struct plugin_list *tracecmd_load_plugins(struct pevent *pevent)
 {
+        struct plugin_list *list = NULL;
         struct dirent *dent;
         struct stat st;
         DIR *dir;
@@ -230,11 +242,10 @@ int trace_load_plugins(struct pevent *pevent)
         char *path;
         int ret;
 
-
         home = getenv("HOME");
 
         if (!home)
-                return -1;
+                return NULL;
 
         path = malloc_or_die(strlen(home) + strlen(PLUGIN_DIR) + 2);
 
@@ -260,12 +271,28 @@ int trace_load_plugins(struct pevent *pevent)
                     strcmp(name, "..") == 0)
                         continue;
 
-                load_plugin(pevent, path, name);
+                list = load_plugin(pevent, list, path, name);
         }
 
         closedir(dir);
  fail:
         free(path);
 
-        return -1;
+        return list;
+}
+
+void tracecmd_unload_plugins(struct plugin_list *plugin_list)
+{
+        pevent_plugin_unload_func func;
+        struct plugin_list *list;
+
+        while (plugin_list) {
+                list = plugin_list;
+                plugin_list = list->next;
+                func = dlsym(list->handle, PEVENT_PLUGIN_UNLOADER_NAME);
+                if (func)
+                        func();
+                dlclose(list->handle);
+                free(list);
+        }
 }