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, 5 insertions, 0 deletions

diff --git a/src/vlib/unix/plugin.h b/src/vlib/unix/plugin.h
index 2a238279401..30039c54d65 100644
--- a/src/vlib/unix/plugin.h
+++ b/src/vlib/unix/plugin.h
@@ -61,6 +61,7 @@ typedef CLIB_PACKED(struct {
   u8 default_disabled;
   const char version[32];
   const char version_required[32];
+  const char overrides[256];
   const char *early_init;
   const char *description;
 }) vlib_plugin_registration_t;
@@ -91,6 +92,7 @@ typedef struct
   /* loaded plugin info */
   plugin_info_t *plugin_info;
   uword *plugin_by_name_hash;
+  uword *plugin_overrides_by_name_hash;
 
   /* paths and name filters */
   u8 *plugin_path;
@@ -103,6 +105,9 @@ typedef struct
   plugin_config_t *configs;
   uword *config_index_by_name;
 
+  /* Plugin log, avoid filling syslog w/ junk */
+  vlib_log_class_t logger;
+
   /* usual */
   vlib_main_t *vlib_main;
 } plugin_main_t;