vlib: add plugin override support

Allow a plugin to override (suppress loading of) other plugins. This
mechanism allows a developer to prevent specific plugins from being
loaded.

To do so, provide an "overrides" list in the plugin definition:

VLIB_PLUGIN_REGISTER () =
{
  <snip>
  .overrides = "avf_plugin.so,ioam_plugin.so,dpdk_plugin.so",
};

or some such. Simply list the plugins in question as shown above. The
.overrides structure member is limited to 256 octets. The named .elf
section mechanism used to discover the vlib_plugin_registration_t's
precludes the use of a variable-length array of strings.

Use the vlib log to eliminate plugin and built-in vat plugin loader
console spew.

Added vlib_log_register_class_rate_limit(...) to allow procedural
configuration of the log rate-limit. We *never* want to rate-limit
plugin loader messages.

Type: feature

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I0a9327b8cf5508482f057342783252112cb44170

1 files changed, 20 insertions, 4 deletions

diff --git a/src/vpp/api/plugin.c b/src/vpp/api/plugin.c
index 73a20d42dc1..410d497a0aa 100644
--- a/src/vpp/api/plugin.c
+++ b/src/vpp/api/plugin.c
@@ -23,6 +23,15 @@
 
 plugin_main_t vat_plugin_main;
 
+static vlib_log_class_t vat_builtin_logger;
+
+#define PLUGIN_LOG_DBG(...) \
+  do {vlib_log_debug (vat_builtin_logger, __VA_ARGS__);} while(0)
+#define PLUGIN_LOG_ERR(...) \
+  do {vlib_log_err (vat_builtin_logger, __VA_ARGS__);} while(0)
+#define PLUGIN_LOG_NOTICE(...) \
+  do {vlib_log_notice (vat_builtin_logger, __VA_ARGS__);} while(0)
+
 static int
 load_one_vat_plugin (plugin_main_t * pm, plugin_info_t * pi)
 {
@@ -39,7 +48,7 @@ load_one_vat_plugin (plugin_main_t * pm, plugin_info_t * pi)
    */
   if (handle == 0)
     {
-      clib_warning ("%s", dlerror ());
+      PLUGIN_LOG_ERR ("%s", dlerror ());
       return 0;
     }
 
@@ -48,7 +57,7 @@ load_one_vat_plugin (plugin_main_t * pm, plugin_info_t * pi)
   register_handle = dlsym (pi->handle, "vat_plugin_register");
   if (register_handle == 0)
     {
-      clib_warning ("%s: symbol vat_plugin_register not found", pi->name);
+      PLUGIN_LOG_ERR ("%s: symbol vat_plugin_register not found", pi->name);
       dlclose (handle);
       return 0;
     }
@@ -59,12 +68,15 @@ load_one_vat_plugin (plugin_main_t * pm, plugin_info_t * pi)
 
   if (error)
     {
-      clib_error_report (error);
+      u8 *err = format (0, "%U%c", format_clib_error, error, 0);
+      PLUGIN_LOG_ERR ((char *) err);
+      clib_error_free (error);
       dlclose (handle);
+      pi->handle = 0;
       return 1;
     }
 
-  clib_warning ("Loaded plugin: %s", pi->name);
+  PLUGIN_LOG_NOTICE ("Loaded plugin: %s", pi->name);
 
   return 0;
 }
@@ -190,6 +202,10 @@ vat_plugin_init (vat_main_t * vam)
   u8 *plugin_path;
   u8 *plugin_name_filter;
 
+  vat_builtin_logger =
+    vlib_log_register_class_rate_limit ("vat-plug", "load",
+					0x7FFFFFFF /* aka no rate limit */ );
+
   plugin_path = vlib_get_vat_plugin_path ();
   plugin_name_filter = vlib_get_vat_plugin_name_filter ();