epan: Initialize wiretap

Clients of libwireshark should not be required to initialize
explicitly wiretap, if they don't use it themselves.

dftest.c

@@ -31,8 +31,6 @@
 #include <wsutil/report_message.h>
 #include <wsutil/wslog.h>
 
-#include <wiretap/wtap.h>
-
 #include "ui/util.h"
 #include "ui/cmdarg_err.h"
 #include "ui/failure_message.h"
@@ -89,13 +87,6 @@ main(int argc, char **argv)
 	timestamp_set_type(TS_RELATIVE);
 	timestamp_set_seconds_type(TS_SECONDS_DEFAULT);
 
-	/*
-	 * Libwiretap must be initialized before libwireshark is, so that
-	 * dissection-time handlers for file-type-dependent blocks can
-	 * register using the file type/subtype value for the file type.
-	 */
-	wtap_init(TRUE);
-
 	/* Register all dissectors; we must do this before checking for the
 	   "-g" flag, as the "-g" flag dumps a list of fields registered
 	   by the dissectors, and we must do it before we read the preferences,

epan/epan.c

@@ -21,6 +21,7 @@
 
 #include <wsutil/report_message.h>
 
+#include <wiretap/wtap.h>
 #include <epan/exceptions.h>
 
 #include "epan.h"
@@ -246,6 +247,8 @@ epan_init(register_cb cb, gpointer client_data, gboolean load_plugins)
 		wireshark_abort_on_too_many_items = FALSE;
 	}
 
+	wtap_init(load_plugins);
+
 	/*
 	 * proto_init -> register_all_protocols -> g_async_queue_new which
 	 * requires threads to be initialized. This happens automatically with
@@ -428,6 +431,8 @@ epan_cleanup(void)
 	}
 
 	wmem_cleanup_scopes();
+
+	wtap_cleanup();
 }
 
 struct epan_session {

wiretap/wtap.c

@@ -25,6 +25,8 @@
 #include <wsutil/plugins.h>
 #endif
 
+static gboolean wiretap_initialized = FALSE;
+
 #ifdef HAVE_PLUGINS
 static plugins_t *libwiretap_plugins = NULL;
 #endif
@@ -1838,6 +1840,9 @@ wtap_full_file_seek_read(wtap *wth, gint64 seek_off, wtap_rec *rec, Buffer *buf,
 void
 wtap_init(gboolean load_wiretap_plugins)
 {
+	if (wiretap_initialized)
+		return;
+
 	init_open_routines();
 	wtap_opttypes_initialize();
 	wtap_init_encap_types();
@@ -1848,6 +1853,7 @@ wtap_init(gboolean load_wiretap_plugins)
 #endif
 		g_slist_foreach(wtap_plugins, call_plugin_register_wtap_module, NULL);
 	}
+	wiretap_initialized = TRUE;
 }
 
 /*
@@ -1856,6 +1862,9 @@ wtap_init(gboolean load_wiretap_plugins)
 void
 wtap_cleanup(void)
 {
+	if (!wiretap_initialized)
+		return;
+
 	wtap_cleanup_encap_types();
 	wtap_opttypes_cleanup();
 	ws_buffer_cleanup();
@@ -1866,6 +1875,7 @@ wtap_cleanup(void)
 	plugins_cleanup(libwiretap_plugins);
 	libwiretap_plugins = NULL;
 #endif
+	wiretap_initialized = FALSE;
 }
 
 /*