/src/strongswan/src/libstrongswan/plugins/plugin_loader.c

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/*
 * Copyright (C) 2010-2014 Tobias Brunner
 * Copyright (C) 2007 Martin Willi
 *
 * Copyright (C) secunet Security Networks AG
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

#define _GNU_SOURCE
#include "plugin_loader.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#ifdef HAVE_DLADDR
#include <dlfcn.h>
#endif
#include <limits.h>
#include <stdio.h>

#include <utils/debug.h>
#include <library.h>
#include <collections/hashtable.h>
#include <collections/array.h>
#include <collections/linked_list.h>
#include <plugins/plugin.h>
#include <utils/integrity_checker.h>

typedef struct private_plugin_loader_t private_plugin_loader_t;
typedef struct registered_feature_t registered_feature_t;
typedef struct provided_feature_t provided_feature_t;
typedef struct plugin_entry_t plugin_entry_t;

#ifdef STATIC_PLUGIN_CONSTRUCTORS
/**
 * Statically registered constructors
 */
static hashtable_t *plugin_constructors = NULL;
#endif

/**
 * private data of plugin_loader
 */
struct private_plugin_loader_t {

  /**
   * public functions
   */
  plugin_loader_t public;

  /**
   * List of plugins, as plugin_entry_t
   */
  linked_list_t *plugins;

  /**
   * Hashtable for registered features, as registered_feature_t
   */
  hashlist_t *features;

  /**
   * Loaded features (stored in reverse order), as provided_feature_t
   */
  linked_list_t *loaded;

  /**
   * List of paths to search for plugins
   */
  linked_list_t *paths;

  /**
   * List of names of loaded plugins
   */
  char *loaded_plugins;

  /**
   * Statistics collected while loading features
   */
  struct {
    /** Number of features that failed to load */
    int failed;
    /** Number of features that failed because of unmet dependencies */
    int depends;
    /** Number of features in critical plugins that failed to load */
    int critical;
  } stats;

  /**
   * Fetch features from the given plugin, can optionally be overridden to
   * modify feature arrays at loading time
   */
  int (*get_features)(plugin_t *plugin, plugin_feature_t *features[]);
};

/**
 * Registered plugin feature
 */
struct registered_feature_t {

  /**
   * The registered feature
   */
  plugin_feature_t *feature;

  /**
   * List of plugins providing this feature, as provided_feature_t
   */
  linked_list_t *plugins;
};

/**
 * Hash a registered feature
 */
static u_int registered_feature_hash(registered_feature_t *this)
{
  return plugin_feature_hash(this->feature);
}

/**
 * Compare two registered features
 */
static bool registered_feature_equals(registered_feature_t *a,
                    registered_feature_t *b)
{
  return plugin_feature_equals(a->feature, b->feature);
}

/**
 * Feature as provided by a plugin
 */
struct provided_feature_t {

  /**
   * Plugin providing the feature
   */
  plugin_entry_t *entry;

  /**
   * FEATURE_REGISTER or FEATURE_CALLBACK entry
   */
  plugin_feature_t *reg;

  /**
   * The provided feature (followed by dependencies)
   */
  plugin_feature_t *feature;

  /**
   * Maximum number of dependencies (following feature)
   */
  int dependencies;

  /**
   * TRUE if currently loading this feature (to prevent loops)
   */
  bool loading;

  /**
   * TRUE if feature loaded
   */
  bool loaded;

  /**
   * TRUE if feature failed to load
   */
  bool failed;
};

/**
 * Entry for a plugin
 */
struct plugin_entry_t {

  /**
   * Plugin instance
   */
  plugin_t *plugin;

  /**
   * TRUE, if the plugin is marked as critical
   */
  bool critical;

  /**
   * dlopen handle, if in separate lib
   */
  void *handle;

  /**
   * List of features, as provided_feature_t
   */
  linked_list_t *features;
};

/**
 * Destroy a plugin entry
 */
static void plugin_entry_destroy(plugin_entry_t *entry)
{
  DESTROY_IF(entry->plugin);
  if (entry->handle)
  {
    dlclose(entry->handle);
  }
  entry->features->destroy(entry->features);
  free(entry);
}

/**
 * Wrapper for static plugin features
 */
typedef struct {

  /**
   * Implements plugin_t interface
   */
  plugin_t public;

  /**
   * Name of the module registering these features
   */
  char *name;

  /**
   * Optional reload function for features
   */
  bool (*reload)(void *data);

  /**
   * User data to pass to reload function
   */
  void *reload_data;

  /**
   * Static plugin features
   */
  plugin_feature_t *features;

  /**
   * Number of plugin features
   */
  int count;

} static_features_t;

METHOD(plugin_t, get_static_name, char*,
  static_features_t *this)
{
  return this->name;
}

METHOD(plugin_t, get_static_features, int,
  static_features_t *this, plugin_feature_t *features[])
{
  *features = this->features;
  return this->count;
}

METHOD(plugin_t, static_reload, bool,
  static_features_t *this)
{
  if (this->reload)
  {
    return this->reload(this->reload_data);
  }
  return FALSE;
}

METHOD(plugin_t, static_destroy, void,
  static_features_t *this)
{
  free(this->features);
  free(this->name);
  free(this);
}

/**
 * Create a wrapper around static plugin features.
 */
static plugin_t *static_features_create(const char *name,
                    plugin_feature_t features[], int count,
                    bool (*reload)(void*), void *reload_data)
{
  static_features_t *this;

  INIT(this,
    .public = {
      .get_name = _get_static_name,
      .get_features = _get_static_features,
      .reload = _static_reload,
      .destroy = _static_destroy,
    },
    .name = strdup(name),
    .reload = reload,
    .reload_data = reload_data,
    .features = calloc(count, sizeof(plugin_feature_t)),
    .count = count,
  );

  memcpy(this->features, features, sizeof(plugin_feature_t) * count);

  return &this->public;
}

#ifdef STATIC_PLUGIN_CONSTRUCTORS
/*
 * Described in header.
 */
void plugin_constructor_register(char *name, void *constructor)
{
  bool old = FALSE;

  if (lib && lib->leak_detective)
  {
    old = lib->leak_detective->set_state(lib->leak_detective, FALSE);
  }

  if (!plugin_constructors)
  {
    chunk_hash_seed();
    plugin_constructors = hashtable_create(hashtable_hash_str,
                         hashtable_equals_str, 32);
  }
  if (constructor)
  {
    plugin_constructors->put(plugin_constructors, name, constructor);
  }
  else
  {
    plugin_constructors->remove(plugin_constructors, name);
    if (!plugin_constructors->get_count(plugin_constructors))
    {
      plugin_constructors->destroy(plugin_constructors);
      plugin_constructors = NULL;
    }
  }

  if (lib && lib->leak_detective)
  {
    lib->leak_detective->set_state(lib->leak_detective, old);
  }
}
#endif

/**
 * create a plugin
 * returns: NOT_FOUND, if the constructor was not found
 *          FAILED, if the plugin could not be constructed
 */
static status_t create_plugin(private_plugin_loader_t *this, void *handle,
                char *name, char *create, bool integrity,
                bool critical, plugin_entry_t **entry)
{
  plugin_t *plugin;
  plugin_constructor_t constructor = NULL;

#ifdef STATIC_PLUGIN_CONSTRUCTORS
  if (plugin_constructors)
  {
    constructor = plugin_constructors->get(plugin_constructors, name);
  }
  if (!constructor)
#endif
  {
    constructor = dlsym(handle, create);
  }
  if (!constructor)
  {
    return NOT_FOUND;
  }
  if (integrity && lib->integrity)
  {
    if (!lib->integrity->check_segment(lib->integrity, name, constructor))
    {
      DBG1(DBG_LIB, "plugin '%s': failed segment integrity test", name);
      return FAILED;
    }
    DBG1(DBG_LIB, "plugin '%s': passed file and segment integrity tests",
       name);
  }
  plugin = constructor();
  if (plugin == NULL)
  {
    DBG1(DBG_LIB, "plugin '%s': failed to load - %s returned NULL", name,
       create);
    return FAILED;
  }
  INIT(*entry,
    .plugin = plugin,
    .critical = critical,
    .features = linked_list_create(),
  );
  DBG2(DBG_LIB, "plugin '%s': loaded successfully", name);
  return SUCCESS;
}

/**
 * load a single plugin
 */
static plugin_entry_t *load_plugin(private_plugin_loader_t *this, char *name,
                   char *file, bool critical)
{
  char create[128];
  plugin_entry_t *entry;
  void *handle;
  int flag = RTLD_LAZY;

  if (snprintf(create, sizeof(create), "%s_plugin_create",
         name) >= sizeof(create))
  {
    return NULL;
  }
  translate(create, "-", "_");
  switch (create_plugin(this, RTLD_DEFAULT, name, create, FALSE, critical,
              &entry))
  {
    case SUCCESS:
      this->plugins->insert_last(this->plugins, entry);
      return entry;
    case NOT_FOUND:
      if (file)
      { /* try to load the plugin from a file */
        break;
      }
      DBG1(DBG_LIB, "plugin '%s': failed to load - %s not found and no "
         "plugin file available", name, create);
      /* fall-through */
    default:
      return NULL;
  }
  if (lib->integrity)
  {
    if (!lib->integrity->check_file(lib->integrity, name, file))
    {
      DBG1(DBG_LIB, "plugin '%s': failed file integrity test of '%s'",
         name, file);
      return NULL;
    }
  }
  if (lib->settings->get_bool(lib->settings, "%s.dlopen_use_rtld_now",
                FALSE, lib->ns))
  {
    flag = RTLD_NOW;
  }
#ifdef RTLD_NODELETE
  /* If supported, do not unload the library when unloading a plugin. It
   * really doesn't matter in productive systems, but causes many (dependency)
   * library reloads during unit tests. Some libraries can't handle that, e.g.
   * GnuTLS leaks file descriptors in its library load/unload functions. */
  flag |= RTLD_NODELETE;
#endif
  handle = dlopen(file, flag);
  if (handle == NULL)
  {
    DBG1(DBG_LIB, "plugin '%s' failed to load: %s", name, dlerror());
    return NULL;
  }
  switch (create_plugin(this, handle, name, create, TRUE, critical, &entry))
  {
    case SUCCESS:
      break;
    case NOT_FOUND:
      DBG1(DBG_LIB, "plugin '%s': failed to load - %s not found", name,
         create);
      /* fall-through */
    default:
      dlclose(handle);
      return NULL;
  }
  entry->handle = handle;
  this->plugins->insert_last(this->plugins, entry);
  return entry;
}

CALLBACK(feature_filter, bool,
  void *null, enumerator_t *orig, va_list args)
{
  provided_feature_t *provided;
  plugin_feature_t **feature;

  VA_ARGS_VGET(args, feature);

  while (orig->enumerate(orig, &provided))
  {
    if (provided->loaded)
    {
      *feature = provided->feature;
      return TRUE;
    }
  }
  return FALSE;
}

CALLBACK(plugin_filter, bool,
  void *null, enumerator_t *orig, va_list args)
{
  plugin_entry_t *entry;
  linked_list_t **list;
  plugin_t **plugin;

  VA_ARGS_VGET(args, plugin, list);

  if (orig->enumerate(orig, &entry))
  {
    *plugin = entry->plugin;
    if (list)
    {
      enumerator_t *features;
      features = enumerator_create_filter(
              entry->features->create_enumerator(entry->features),
              feature_filter, NULL, NULL);
      *list = linked_list_create_from_enumerator(features);
    }
    return TRUE;
  }
  return FALSE;
}

METHOD(plugin_loader_t, create_plugin_enumerator, enumerator_t*,
  private_plugin_loader_t *this)
{
  return enumerator_create_filter(
              this->plugins->create_enumerator(this->plugins),
              plugin_filter, NULL, NULL);
}

METHOD(plugin_loader_t, has_feature, bool,
  private_plugin_loader_t *this, plugin_feature_t feature)
{
  enumerator_t *plugins, *features;
  plugin_t *plugin;
  linked_list_t *list;
  plugin_feature_t *current;
  bool found = FALSE;

  plugins = create_plugin_enumerator(this);
  while (plugins->enumerate(plugins, &plugin, &list))
  {
    features = list->create_enumerator(list);
    while (features->enumerate(features, &current))
    {
      if (plugin_feature_matches(&feature, current))
      {
        found = TRUE;
        break;
      }
    }
    features->destroy(features);
    list->destroy(list);
  }
  plugins->destroy(plugins);

  return found;
}

/**
 * Create a list of the names of all loaded plugins
 */
static char* loaded_plugins_list(private_plugin_loader_t *this)
{
  int buf_len = 128, len = 0;
  char *buf, *name;
  enumerator_t *enumerator;
  plugin_t *plugin;

  buf = malloc(buf_len);
  buf[0] = '\0';
  enumerator = create_plugin_enumerator(this);
  while (enumerator->enumerate(enumerator, &plugin, NULL))
  {
    name = plugin->get_name(plugin);
    if (len + (strlen(name) + 1) >= buf_len)
    {
      buf_len <<= 1;
      buf = realloc(buf, buf_len);
    }
    len += snprintf(&buf[len], buf_len - len, "%s ", name);
  }
  enumerator->destroy(enumerator);
  if (len > 0 && buf[len - 1] == ' ')
  {
    buf[len - 1] = '\0';
  }
  return buf;
}

/**
 * Check if a plugin is already loaded
 */
static bool plugin_loaded(private_plugin_loader_t *this, char *name)
{
  enumerator_t *enumerator;
  bool found = FALSE;
  plugin_t *plugin;

  enumerator = create_plugin_enumerator(this);
  while (enumerator->enumerate(enumerator, &plugin, NULL))
  {
    if (streq(plugin->get_name(plugin), name))
    {
      found = TRUE;
      break;
    }
  }
  enumerator->destroy(enumerator);
  return found;
}

/**
 * Forward declaration
 */
static void load_provided(private_plugin_loader_t *this,
              provided_feature_t *provided,
              int level);

CALLBACK(is_feature_loaded, bool,
  provided_feature_t *item, va_list args)
{
  return item->loaded;
}

CALLBACK(is_feature_loadable, bool,
  provided_feature_t *item, va_list args)
{
  return !item->loading && !item->loaded && !item->failed;
}

/**
 * Find a loaded and matching feature
 */
static bool loaded_feature_matches(registered_feature_t *a,
                   registered_feature_t *b)
{
  if (plugin_feature_matches(a->feature, b->feature))
  {
    return b->plugins->find_first(b->plugins, is_feature_loaded, NULL);
  }
  return FALSE;
}

/**
 * Find a loadable module that equals the requested feature
 */
static bool loadable_feature_equals(registered_feature_t *a,
                  registered_feature_t *b)
{
  if (plugin_feature_equals(a->feature, b->feature))
  {
    return b->plugins->find_first(b->plugins, is_feature_loadable, NULL);
  }
  return FALSE;
}

/**
 * Find a loadable module that matches the requested feature
 */
static bool loadable_feature_matches(registered_feature_t *a,
                   registered_feature_t *b)
{
  if (plugin_feature_matches(a->feature, b->feature))
  {
    return b->plugins->find_first(b->plugins, is_feature_loadable, NULL);
  }
  return FALSE;
}

/**
 * Returns a compatible plugin feature for the given dependency
 */
static bool find_compatible_feature(private_plugin_loader_t *this,
                  plugin_feature_t *dependency)
{
  registered_feature_t *feature, lookup = {
    .feature = dependency,
  };

  feature = this->features->get_match(this->features, &lookup,
                     (void*)loaded_feature_matches);
  return feature != NULL;
}

/**
 * Load a registered plugin feature
 */
static void load_registered(private_plugin_loader_t *this,
              registered_feature_t *registered,
              int level)
{
  enumerator_t *enumerator;
  provided_feature_t *provided;

  enumerator = registered->plugins->create_enumerator(registered->plugins);
  while (enumerator->enumerate(enumerator, &provided))
  {
    load_provided(this, provided, level);
  }
  enumerator->destroy(enumerator);
}

/**
 * Try to load dependencies of the given feature
 */
static bool load_dependencies(private_plugin_loader_t *this,
                provided_feature_t *provided,
                int level)
{
  registered_feature_t *registered, lookup;
  int i;

  /* first entry is provided feature, followed by dependencies */
  for (i = 1; i < provided->dependencies; i++)
  {
    if (provided->feature[i].kind != FEATURE_DEPENDS &&
      provided->feature[i].kind != FEATURE_SDEPEND)
    { /* end of dependencies */
      break;
    }

    /* we load the feature even if a compatible one is already loaded,
     * otherwise e.g. a specific database implementation loaded before
     * another might cause a plugin feature loaded in-between to fail */
    lookup.feature = &provided->feature[i];
    do
    { /* prefer an exactly matching feature, could be omitted but
       * results in a more predictable behavior */
      registered = this->features->get_match(this->features,
                     &lookup,
                     (void*)loadable_feature_equals);
      if (!registered)
      { /* try fuzzy matching */
        registered = this->features->get_match(this->features,
                     &lookup,
                     (void*)loadable_feature_matches);
      }
      if (registered)
      {
        load_registered(this, registered, level);
      }
      /* we could stop after finding one but for dependencies like
       * DB_ANY it might be needed to load all matching features */
    }
    while (registered);

    if (!find_compatible_feature(this, &provided->feature[i]))
    {
      bool soft = provided->feature[i].kind == FEATURE_SDEPEND;

#if !defined(USE_FUZZING) && DEBUG_LEVEL >= 1
      char *name, *provide, *depend;
#if DEBUG_LEVEL >= 3
      int indent = level * 2;
#endif
      name = provided->entry->plugin->get_name(provided->entry->plugin);
      provide = plugin_feature_get_string(&provided->feature[0]);
      depend = plugin_feature_get_string(&provided->feature[i]);
      if (soft)
      {
        DBG3(DBG_LIB, "%*sfeature %s in plugin '%s' has unmet soft "
           "dependency: %s", indent, "", provide, name, depend);
      }
      else if (provided->entry->critical)
      {
        DBG1(DBG_LIB, "feature %s in critical plugin '%s' has unmet "
           "dependency: %s", provide, name, depend);
      }
      else
      {
        DBG2(DBG_LIB, "feature %s in plugin '%s' has unmet dependency: "
           "%s", provide, name, depend);
      }
      free(provide);
      free(depend);
#endif /* !USE_FUZZING && DEBUG_LEVEL */

      if (soft)
      { /* it's ok if we can't resolve soft dependencies */
        continue;
      }
      return FALSE;
    }
  }
  return TRUE;
}

/**
 * Load registered plugin features
 */
static void load_feature(private_plugin_loader_t *this,
             provided_feature_t *provided,
             int level)
{
  if (load_dependencies(this, provided, level))
  {
    if (plugin_feature_load(provided->entry->plugin, provided->feature,
                provided->reg))
    {
      provided->loaded = TRUE;
      /* insert first so we can unload the features in reverse order */
      this->loaded->insert_first(this->loaded, provided);
      return;
    }

#if !defined(USE_FUZZING) && DEBUG_LEVEL >= 1
    char *name, *provide;

    name = provided->entry->plugin->get_name(provided->entry->plugin);
    provide = plugin_feature_get_string(&provided->feature[0]);
    if (provided->entry->critical)
    {
      DBG1(DBG_LIB, "feature %s in critical plugin '%s' failed to load",
         provide, name);
    }
    else
    {
      DBG2(DBG_LIB, "feature %s in plugin '%s' failed to load",
         provide, name);
    }
    free(provide);
#endif /* !USE_FUZZING && DEBUG_LEVEL */
  }
  else
  { /* TODO: we could check the current level and set a different flag when
     * being loaded as dependency. If there are loops there is a chance the
     * feature can be loaded later when loading the feature directly. */
    this->stats.depends++;
  }
  provided->failed = TRUE;
  this->stats.critical += provided->entry->critical ? 1 : 0;
  this->stats.failed++;
}

/**
 * Load a provided feature
 */
static void load_provided(private_plugin_loader_t *this,
              provided_feature_t *provided,
              int level)
{
  if (provided->loaded || provided->failed)
  {
    return;
  }

#if !defined(USE_FUZZING) && DEBUG_LEVEL >= 3
  char *name, *provide;
  int indent = level * 2;

  name = provided->entry->plugin->get_name(provided->entry->plugin);
  provide = plugin_feature_get_string(provided->feature);
  if (provided->loading)
  { /* prevent loop */
    DBG3(DBG_LIB, "%*sloop detected while loading %s in plugin '%s'",
       indent, "", provide, name);
    free(provide);
    return;
  }
  DBG3(DBG_LIB, "%*sloading feature %s in plugin '%s'",
     indent, "", provide, name);
  free(provide);
#else
  if (provided->loading)
  {
    return;
  }
#endif /* USE_FUZZING && DEBUG_LEVEL */

  provided->loading = TRUE;
  load_feature(this, provided, level + 1);
  provided->loading = FALSE;
}

/**
 * Load registered plugin features
 */
static void load_features(private_plugin_loader_t *this)
{
  enumerator_t *enumerator, *inner;
  plugin_entry_t *plugin;
  provided_feature_t *provided;

  /* we do this in plugin order to allow implicit dependencies to be resolved
   * by reordering plugins */
  enumerator = this->plugins->create_enumerator(this->plugins);
  while (enumerator->enumerate(enumerator, &plugin))
  {
    inner = plugin->features->create_enumerator(plugin->features);
    while (inner->enumerate(inner, &provided))
    {
      load_provided(this, provided, 0);
    }
    inner->destroy(inner);
  }
  enumerator->destroy(enumerator);
}

/**
 * Default implementation for plugin feature retrieval
 */
static int get_features_default(plugin_t *plugin, plugin_feature_t *features[])
{
  return plugin->get_features(plugin, features);
}

/**
 * Register plugin features provided by the given plugin
 */
static void register_features(private_plugin_loader_t *this,
                plugin_entry_t *entry)
{
  plugin_feature_t *feature, *reg;
  registered_feature_t *registered, lookup;
  provided_feature_t *provided;
  int count, i;

  if (!entry->plugin->get_features)
  { /* feature interface not supported */
    DBG1(DBG_LIB, "plugin '%s' does not provide features, deprecated",
       entry->plugin->get_name(entry->plugin));
    return;
  }
  reg = NULL;
  count = this->get_features(entry->plugin, &feature);
  for (i = 0; i < count; i++)
  {
    switch (feature->kind)
    {
      case FEATURE_PROVIDE:
        lookup.feature = feature;
        registered = this->features->ht.get(&this->features->ht,
                          &lookup);
        if (!registered)
        {
          INIT(registered,
            .feature = feature,
            .plugins = linked_list_create(),
          );
          this->features->ht.put(&this->features->ht, registered,
                       registered);
        }
        INIT(provided,
          .entry = entry,
          .feature = feature,
          .reg = reg,
          .dependencies = count - i,
        );
        registered->plugins->insert_last(registered->plugins,
                         provided);
        entry->features->insert_last(entry->features, provided);
        break;
      case FEATURE_REGISTER:
      case FEATURE_CALLBACK:
        reg = feature;
        break;
      default:
        break;
    }
    feature++;
  }
}

/**
 * Unregister a plugin feature
 */
static void unregister_feature(private_plugin_loader_t *this,
                 provided_feature_t *provided)
{
  registered_feature_t *registered, lookup;

  lookup.feature = provided->feature;
  registered = this->features->ht.get(&this->features->ht, &lookup);
  if (registered)
  {
    registered->plugins->remove(registered->plugins, provided, NULL);
    if (registered->plugins->get_count(registered->plugins) == 0)
    {
      this->features->ht.remove(&this->features->ht, &lookup);
      registered->plugins->destroy(registered->plugins);
      free(registered);
    }
    else if (registered->feature == provided->feature)
    { /* update feature in case the providing plugin gets unloaded */
      provided_feature_t *first;

      registered->plugins->get_first(registered->plugins, (void**)&first);
      registered->feature = first->feature;
    }
  }
  free(provided);
}

/**
 * Unregister plugin features
 */
static void unregister_features(private_plugin_loader_t *this,
                plugin_entry_t *entry)
{
  provided_feature_t *provided;
  enumerator_t *enumerator;

  enumerator = entry->features->create_enumerator(entry->features);
  while (enumerator->enumerate(enumerator, &provided))
  {
    entry->features->remove_at(entry->features, enumerator);
    unregister_feature(this, provided);
  }
  enumerator->destroy(enumerator);
}

/**
 * Remove plugins we were not able to load any plugin features from.
 */
static void purge_plugins(private_plugin_loader_t *this)
{
  enumerator_t *enumerator;
  plugin_entry_t *entry;

  enumerator = this->plugins->create_enumerator(this->plugins);
  while (enumerator->enumerate(enumerator, &entry))
  {
    if (!entry->plugin->get_features)
    { /* feature interface not supported */
      continue;
    }
    if (!entry->features->find_first(entry->features, is_feature_loaded,
                     NULL))
    {
      DBG2(DBG_LIB, "unloading plugin '%s' without loaded features",
         entry->plugin->get_name(entry->plugin));
      this->plugins->remove_at(this->plugins, enumerator);
      unregister_features(this, entry);
      plugin_entry_destroy(entry);
    }
  }
  enumerator->destroy(enumerator);
}

METHOD(plugin_loader_t, add_static_features, void,
  private_plugin_loader_t *this, const char *name,
  plugin_feature_t features[], int count, bool critical,
  bool (*reload)(void*), void *reload_data)
{
  plugin_entry_t *entry;
  plugin_t *plugin;

  plugin = static_features_create(name, features, count, reload, reload_data);

  INIT(entry,
    .plugin = plugin,
    .critical = critical,
    .features = linked_list_create(),
  );
  this->plugins->insert_last(this->plugins, entry);
  register_features(this, entry);
}

/**
 * Tries to find the plugin with the given name in the given path.
 */
static bool find_plugin(char *path, char *name, char *buf, char **file)
{
  struct stat stb;

  if (path && snprintf(buf, PATH_MAX, "%s/libstrongswan-%s.so",
             path, name) < PATH_MAX)
  {
    if (stat(buf, &stb) == 0)
    {
      *file = buf;
      return TRUE;
    }
  }
  return FALSE;
}

CALLBACK(find_plugin_cb, bool,
  char *path, va_list args)
{
  char *name, *buf, **file;

  VA_ARGS_VGET(args, name, buf, file);
  return find_plugin(path, name, buf, file);
}

/**
 * Used to sort plugins by priority
 */
typedef struct {
  /* name of the plugin */
  char *name;
  /* the plugins priority */
  int prio;
  /* default priority */
  int def;
} plugin_priority_t;

static void plugin_priority_free(const plugin_priority_t *this, int idx,
                 void *user)
{
  free(this->name);
}

/**
 * Sort plugins and their priority by name
 */
static int plugin_priority_cmp_name(const plugin_priority_t *a,
                    const plugin_priority_t *b)
{
  return strcmp(a->name, b->name);
}

/**
 * Sort plugins by decreasing priority or default priority then by name
 */
static int plugin_priority_cmp(const plugin_priority_t *a,
                 const plugin_priority_t *b, void *user)
{
  int diff;

  diff = b->prio - a->prio;
  if (!diff)
  { /* the same priority, use default order */
    diff = b->def - a->def;
    if (!diff)
    { /* same default priority (i.e. both were not found in that list) */
      return strcmp(a->name, b->name);
    }
  }
  return diff;
}

CALLBACK(plugin_priority_filter, bool,
  void *null, enumerator_t *orig, va_list args)
{
  plugin_priority_t *prio;
  char **name;

  VA_ARGS_VGET(args, name);

  if (orig->enumerate(orig, &prio))
  {
    *name = prio->name;
    return TRUE;
  }
  return FALSE;
}

/**
 * Determine the list of plugins to load via load option in each plugin's
 * config section.
 */
static char *modular_pluginlist(char *list)
{
  enumerator_t *enumerator;
  array_t *given, *final;
  plugin_priority_t item, *current, found;
  char *plugin, *plugins = NULL;
  int i = 0, max_prio;
  bool load_def = FALSE;

  given = array_create(sizeof(plugin_priority_t), 0);
  final = array_create(sizeof(plugin_priority_t), 0);

  enumerator = enumerator_create_token(list, " ", " ");
  while (enumerator->enumerate(enumerator, &plugin))
  {
    item.name = strdup(plugin);
    item.prio = i++;
    array_insert(given, ARRAY_TAIL, &item);
  }
  enumerator->destroy(enumerator);
  array_sort(given, (void*)plugin_priority_cmp_name, NULL);
  /* the maximum priority used for plugins not found in this list */
  max_prio = i + 1;

  if (lib->settings->get_bool(lib->settings, "%s.load_modular", FALSE,
                lib->ns))
  {
    enumerator = lib->settings->create_section_enumerator(lib->settings,
                            "%s.plugins", lib->ns);
  }
  else
  {
    enumerator = enumerator_create_filter(array_create_enumerator(given),
                    plugin_priority_filter, NULL, NULL);
    load_def = TRUE;
  }
  while (enumerator->enumerate(enumerator, &plugin))
  {
    item.prio = lib->settings->get_int(lib->settings,
              "%s.plugins.%s.load", 0, lib->ns, plugin);
    if (!item.prio)
    {
      if (!lib->settings->get_bool(lib->settings,
              "%s.plugins.%s.load", load_def, lib->ns, plugin))
      {
        continue;
      }
      item.prio = 1;
    }
    item.name = plugin;
    item.def = max_prio;
    if (array_bsearch(given, &item, (void*)plugin_priority_cmp_name,
              &found) != -1)
    {
      item.def = max_prio - found.prio;
    }
    array_insert(final, ARRAY_TAIL, &item);
  }
  enumerator->destroy(enumerator);

  array_sort(final, (void*)plugin_priority_cmp, NULL);

  plugins = strdup("");
  enumerator = array_create_enumerator(final);
  while (enumerator->enumerate(enumerator, &current))
  {
    char *prev = plugins;
    if (asprintf(&plugins, "%s %s", plugins ?: "", current->name) < 0)
    {
      plugins = prev;
      break;
    }
    free(prev);
  }
  enumerator->destroy(enumerator);
  array_destroy_function(given, (void*)plugin_priority_free, NULL);
  array_destroy(final);
  return plugins;
}

METHOD(plugin_loader_t, load_plugins, bool,
  private_plugin_loader_t *this, char *list)
{
  enumerator_t *enumerator;
  char *default_path = NULL, *plugins, *token;
  bool critical_failed = FALSE;

#ifdef PLUGINDIR
  default_path = PLUGINDIR;
#endif /* PLUGINDIR */

  plugins = modular_pluginlist(list);

  enumerator = enumerator_create_token(plugins, " ", " ");
  while (!critical_failed && enumerator->enumerate(enumerator, &token))
  {
    plugin_entry_t *entry;
    bool critical = FALSE;
    char buf[PATH_MAX], *file = NULL;
    int len;

    token = strdup(token);
    len = strlen(token);
    if (token[len-1] == '!')
    {
      critical = TRUE;
      token[len-1] = '\0';
    }
    if (plugin_loaded(this, token))
    {
      free(token);
      continue;
    }
    if (this->paths)
    {
      this->paths->find_first(this->paths, find_plugin_cb, NULL, token,
                  buf, &file);
    }
    if (!file)
    {
      find_plugin(default_path, token, buf, &file);
    }
    entry = load_plugin(this, token, file, critical);
    if (entry)
    {
      register_features(this, entry);
    }
    else if (critical)
    {
      critical_failed = TRUE;
      DBG1(DBG_LIB, "loading critical plugin '%s' failed", token);
    }
    free(token);
  }
  enumerator->destroy(enumerator);
  if (!critical_failed)
  {
    load_features(this);
    if (this->stats.critical > 0)
    {
      critical_failed = TRUE;
      DBG1(DBG_LIB, "failed to load %d critical plugin feature%s",
         this->stats.critical, this->stats.critical == 1 ? "" : "s");
    }
    /* unload plugins that we were not able to load any features for */
    purge_plugins(this);
  }
  if (!critical_failed)
  {
    free(this->loaded_plugins);
    this->loaded_plugins = loaded_plugins_list(this);
  }
  if (plugins != list)
  {
    free(plugins);
  }
  return !critical_failed;
}

/**
 * Unload plugin features, they are registered in reverse order
 */
static void unload_features(private_plugin_loader_t *this)
{
  enumerator_t *enumerator;
  provided_feature_t *provided;
  plugin_entry_t *entry;

  enumerator = this->loaded->create_enumerator(this->loaded);
  while (enumerator->enumerate(enumerator, &provided))
  {
    entry = provided->entry;
    plugin_feature_unload(entry->plugin, provided->feature, provided->reg);
    this->loaded->remove_at(this->loaded, enumerator);
    entry->features->remove(entry->features, provided, NULL);
    unregister_feature(this, provided);
  }
  enumerator->destroy(enumerator);
}

METHOD(plugin_loader_t, unload, void,
  private_plugin_loader_t *this)
{
  plugin_entry_t *entry;

  /* unload features followed by plugins, in reverse order */
  unload_features(this);
  while (this->plugins->remove_last(this->plugins, (void**)&entry) == SUCCESS)
  {
    if (lib->leak_detective)
    { /* keep handle to report leaks properly */
      entry->handle = NULL;
    }
    unregister_features(this, entry);
    plugin_entry_destroy(entry);
  }
  free(this->loaded_plugins);
  this->loaded_plugins = NULL;
  memset(&this->stats, 0, sizeof(this->stats));
}

METHOD(plugin_loader_t, add_path, void,
  private_plugin_loader_t *this, char *path)
{
  if (!this->paths)
  {
    this->paths = linked_list_create();
  }
  this->paths->insert_last(this->paths, strdupnull(path));
}

/**
 * Reload a plugin by name, NULL for all
 */
static u_int reload_by_name(private_plugin_loader_t *this, char *name)
{
  u_int reloaded = 0;
  enumerator_t *enumerator;
  plugin_t *plugin;

  enumerator = create_plugin_enumerator(this);
  while (enumerator->enumerate(enumerator, &plugin, NULL))
  {
    if (name == NULL || streq(name, plugin->get_name(plugin)))
    {
      if (plugin->reload && plugin->reload(plugin))
      {
        DBG2(DBG_LIB, "reloaded configuration of '%s' plugin",
           plugin->get_name(plugin));
        reloaded++;
      }
    }
  }
  enumerator->destroy(enumerator);
  return reloaded;
}

METHOD(plugin_loader_t, reload, u_int,
  private_plugin_loader_t *this, char *list)
{
  u_int reloaded = 0;
  enumerator_t *enumerator;
  char *name;

  if (list == NULL)
  {
    return reload_by_name(this, NULL);
  }
  enumerator = enumerator_create_token(list, " ", "");
  while (enumerator->enumerate(enumerator, &name))
  {
    reloaded += reload_by_name(this, name);
  }
  enumerator->destroy(enumerator);
  return reloaded;
}

METHOD(plugin_loader_t, loaded_plugins, char*,
  private_plugin_loader_t *this)
{
  return this->loaded_plugins ?: "";
}

METHOD(plugin_loader_t, status, void,
  private_plugin_loader_t *this, level_t level)
{
  if (this->loaded_plugins)
  {
    dbg(DBG_LIB, level, "loaded plugins: %s", this->loaded_plugins);

    if (this->stats.failed)
    {
      DBG2(DBG_LIB, "unable to load %d plugin feature%s (%d due to unmet "
         "dependencies)", this->stats.failed,
         this->stats.failed == 1 ? "" : "s", this->stats.depends);
    }
  }
}

METHOD(plugin_loader_t, destroy, void,
  private_plugin_loader_t *this)
{
  unload(this);
  this->features->destroy(this->features);
  this->loaded->destroy(this->loaded);
  this->plugins->destroy(this->plugins);
  DESTROY_FUNCTION_IF(this->paths, free);
  free(this->loaded_plugins);
  free(this);
}

/*
 * see header file
 */
plugin_loader_t *plugin_loader_create()
{
  private_plugin_loader_t *this;

  INIT(this,
    .public = {
      .add_static_features = _add_static_features,
      .load = _load_plugins,
      .add_path = _add_path,
      .reload = _reload,
      .unload = _unload,
      .create_plugin_enumerator = _create_plugin_enumerator,
      .has_feature = _has_feature,
      .loaded_plugins = _loaded_plugins,
      .status = _status,
      .destroy = _destroy,
    },
    .plugins = linked_list_create(),
    .loaded = linked_list_create(),
    .features = hashlist_create(
              (hashtable_hash_t)registered_feature_hash,
              (hashtable_equals_t)registered_feature_equals, 64),
    .get_features = dlsym(RTLD_DEFAULT, "plugin_loader_feature_filter"),
  );

  if (!this->get_features)
  {
    this->get_features = get_features_default;
  }

  return &this->public;
}

/*
 * See header
 */
void plugin_loader_add_plugindirs(char *basedir, char *plugins)
{
  enumerator_t *enumerator;
  char *name, path[PATH_MAX], dir[64];

  enumerator = enumerator_create_token(plugins, " ", "!");
  while (enumerator->enumerate(enumerator, &name))
  {
    snprintf(dir, sizeof(dir), "%s", name);
    translate(dir, "-", "_");
    snprintf(path, sizeof(path), "%s/%s/.libs", basedir, dir);
    lib->plugins->add_path(lib->plugins, path);
  }
  enumerator->destroy(enumerator);
}

Coverage Report

Created: 2024-02-29 06:05