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// Copyright (C) 2013-2018 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#include <config.h>
#include <exceptions/exceptions.h>
#include <hooks/hooks_log.h>
#include <hooks/server_hooks.h>
#include <algorithm>
#include <utility>
#include <vector>
using namespace std;
using namespace isc;
namespace isc {
namespace hooks {
// Constructor - register the pre-defined hooks and check that the indexes
// assigned to them are as expected.
//
// Note that there are no logging messages here or in registerHooks(). The
// recommended way to initialize hook names is to use static initialization.
// Here, a static object is declared in a file outside of any function or
// method. As a result, it is instantiated and its constructor run before the
// program starts. By putting calls to ServerHooks::registerHook() in there,
// hooks names are already registered when the program runs. However, at that
// point, the logging system is not initialized, so messages are unable to
// be output.
ServerHooks::ServerHooks() {
initialize();
}
// Register a hook. The index assigned to the hook is the current number
// of entries in the collection, so ensuring that hook indexes are unique
// and non-negative.
int
ServerHooks::registerHook(const string& name) {
// Determine index for the new element and insert.
int index = hooks_.size();
pair<HookCollection::iterator, bool> result =
hooks_.insert(make_pair(name, index));
/// @todo: We also need to call CalloutManager::ensureVectorSize(), so it
/// adjusts its vector. Since CalloutManager is not a singleton, there's
/// no getInstance() or similar. Also, CalloutManager uses ServerHooks,
/// so such a call would induce circular dependencies. Ugh.
if (!result.second) {
// There's a problem with hook libraries that need to be linked with
// libdhcpsrv. For example host_cmds hook library requires host
// parser, so it needs to be linked with libdhcpsrv. However, when
// unit-tests are started, the hook points are not registered.
// When the library is loaded new hook points are registered.
// This causes issues in the hooks framework, especially when
// LibraryManager::unloadLibrary() iterates through all hooks
// and then calls deregisterAllCallouts. This method gets
// hook_index that is greater than number of elements in
// hook_vector_ and then we have a read past the array boundary.
/// @todo: See ticket 5251 and 5208 for details.
return (getIndex(name));
// New element was not inserted because an element with the same name
// already existed.
//isc_throw(DuplicateHook, "hook with name " << name <<
// " is already registered");
}
// Element was inserted, so add to the inverse hooks collection.
inverse_hooks_[index] = name;
// ... and return numeric index.
return (index);
}
// Set ServerHooks object to initial state.
void
ServerHooks::initialize() {
// Clear out the name->index and index->name maps.
hooks_.clear();
inverse_hooks_.clear();
parking_lots_.reset(new ParkingLots());
// Register the pre-defined hooks.
int create = registerHook("context_create");
int destroy = registerHook("context_destroy");
// Check registration went as expected.
if ((create != CONTEXT_CREATE) || (destroy != CONTEXT_DESTROY)) {
isc_throw(Unexpected, "pre-defined hook indexes are not as expected. "
"context_create: expected = " << CONTEXT_CREATE <<
", actual = " << create <<
". context_destroy: expected = " << CONTEXT_DESTROY <<
", actual = " << destroy);
}
}
// Reset ServerHooks object to initial state.
void
ServerHooks::reset() {
// Clear all hooks then initialize the pre-defined ones.
initialize();
// Log a warning - although this is done during testing, it should never be
// seen in a production system.
LOG_WARN(hooks_logger, HOOKS_HOOK_LIST_RESET);
}
// Find the name associated with a hook index.
std::string
ServerHooks::getName(int index) const {
// Get iterator to matching element.
InverseHookCollection::const_iterator i = inverse_hooks_.find(index);
if (i == inverse_hooks_.end()) {
isc_throw(NoSuchHook, "hook index " << index << " is not recognized");
}
return (i->second);
}
// Find the index associated with a hook name.
int
ServerHooks::getIndex(const string& name) const {
// Get iterator to matching element.
HookCollection::const_iterator i = hooks_.find(name);
if (i == hooks_.end()) {
isc_throw(NoSuchHook, "hook name " << name << " is not recognized");
}
return (i->second);
}
int
ServerHooks::findIndex(const std::string& name) const {
// Get iterator to matching element.
auto i = hooks_.find(name);
return ((i == hooks_.end()) ? -1 : i->second);
}
// Return vector of hook names. The names are not sorted - it is up to the
// caller to perform sorting if required.
vector<string>
ServerHooks::getHookNames() const {
vector<string> names;
HookCollection::const_iterator i;
for (i = hooks_.begin(); i != hooks_.end(); ++i) {
names.push_back(i->first);
}
return (names);
}
// Return global ServerHooks object
ServerHooks&
ServerHooks::getServerHooks() {
return (*getServerHooksPtr());
}
ServerHooksPtr
ServerHooks::getServerHooksPtr() {
static ServerHooksPtr hooks(new ServerHooks());
return (hooks);
}
ParkingLotsPtr
ServerHooks::getParkingLotsPtr() const {
return (parking_lots_);
}
ParkingLotPtr
ServerHooks::getParkingLotPtr(const int hook_index) {
return (parking_lots_->getParkingLotPtr(hook_index));
}
ParkingLotPtr
ServerHooks::getParkingLotPtr(const std::string& hook_name) {
return (parking_lots_->getParkingLotPtr(getServerHooks().getIndex(hook_name)));
}
std::string
ServerHooks::commandToHookName(const std::string& command_name) {
// Prefix the command name with a dollar sign.
std::string hook_name = std::string("$") + command_name;
// Replace all hyphens with underscores.
std::replace(hook_name.begin(), hook_name.end(), '-', '_');
return (hook_name);
}
std::string
ServerHooks::hookToCommandName(const std::string& hook_name) {
if (!hook_name.empty() && hook_name.front() == '$') {
std::string command_name = hook_name.substr(1);
std::replace(command_name.begin(), command_name.end(), '_', '-');
return (command_name);
}
return ("");
}
} // namespace hooks
} // namespace isc
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