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Kea 2.7.3
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Library manager. More...
#include <library_manager.h>
Public Member Functions | |
LibraryManager (const std::string &name, int index, const boost::shared_ptr< CalloutManager > &manager) | |
Constructor. | |
~LibraryManager () | |
Destructor. | |
std::string | getName () const |
Return library name. | |
bool | loadLibrary (bool multi_threading_enabled=false) |
Loads a library. | |
bool | prepareUnloadLibrary () |
Prepares library unloading. | |
Static Public Member Functions | |
static bool | validateLibrary (const std::string &name, bool multi_threading_enabled=false) |
Validate library. | |
Protected Member Functions | |
bool | checkMultiThreadingCompatible (bool multi_threading_enabled) const |
Check multi-threading compatibility. | |
bool | checkVersion () const |
Check library version. | |
bool | closeLibrary () |
Close library. | |
bool | openLibrary () |
Open library. | |
void | registerStandardCallouts () |
Register standard callouts. | |
bool | runLoad () |
Run the load function if present. | |
bool | unloadLibrary () |
Unloads a library. | |
Library manager.
This class handles the loading and unloading of a specific library. It also provides a static method for checking that a library is valid (this is used in configuration parsing).
On loading, it opens the library using dlopen and checks the version (set with the "version" method. If all is OK, it iterates through the list of known hooks and locates their symbols, registering each callout as it does so. Finally it locates the "load" function (if present) and calls it.
On unload, it clears the callouts on all hooks, calls the "unload" method if present, clears the callouts on all hooks, and closes the library.
When validating a library, only the fact that the library can be opened and version() exists and returns the correct number is checked. The library is closed after the validation.
Definition at line 73 of file library_manager.h.
isc::hooks::LibraryManager::LibraryManager | ( | const std::string & | name, |
int | index, | ||
const boost::shared_ptr< CalloutManager > & | manager ) |
Constructor.
This constructor is used by external agencies (i.e. the LibraryManagerCollection) when instantiating a LibraryManager. It stores the library name - the actual actual loading is done in loadLibrary().
name | Name of the library to load. This should be an absolute path name. |
index | Index of this library |
manager | CalloutManager object |
NoCalloutManager | Thrown if the manager argument is NULL. |
Definition at line 33 of file library_manager.cc.
References isc_throw.
isc::hooks::LibraryManager::~LibraryManager | ( | ) |
Destructor.
If the library is open, closes it. This is principally a safety feature to ensure closure in the case of an exception destroying this object. However, see the caveat in the class header about when it is safe to close libraries.
Definition at line 57 of file library_manager.cc.
References closeLibrary(), and prepareUnloadLibrary().
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protected |
Check multi-threading compatibility.
If the multi-threading mode is disabled returns true, else with the library open, accesses the "multi_threading_compatible()" function and returns false if not exists or has value 0, returns true otherwise.
multi_threading_enabled | The flag which indicates if MT is enabled (used to check hook libraries compatibility with MT). |
Definition at line 142 of file library_manager.cc.
References isc::hooks::HOOKS_DBG_CALLS, isc::hooks::HOOKS_LIBRARY_MULTI_THREADING_COMPATIBLE, isc::hooks::HOOKS_LIBRARY_MULTI_THREADING_NOT_COMPATIBLE, isc::hooks::hooks_logger, isc::hooks::HOOKS_MULTI_THREADING_COMPATIBLE_EXCEPTION, LOG_DEBUG, and LOG_ERROR.
Referenced by loadLibrary().
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Check library version.
With the library open, accesses the "version()" function and, if present, checks the returned value against the hooks version symbol for the currently running Kea. The "version()" function is mandatory and must be present (and return the correct value) for the library to load.
If there is no version() function, or if there is a mismatch in version number, a message logged.
Definition at line 109 of file library_manager.cc.
References isc::hooks::HOOKS_DBG_CALLS, isc::hooks::HOOKS_INCORRECT_VERSION, isc::hooks::HOOKS_LIBRARY_VERSION, isc::hooks::hooks_logger, isc::hooks::HOOKS_NO_VERSION, isc::hooks::HOOKS_VERSION_EXCEPTION, LOG_DEBUG, LOG_ERROR, and version().
Referenced by loadLibrary().
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Close library.
Closes the library associated with this LibraryManager. A message is logged on an error.
Definition at line 88 of file library_manager.cc.
References isc::hooks::HOOKS_CLOSE_ERROR, isc::hooks::HOOKS_LIBRARY_CLOSED, isc::hooks::hooks_logger, LOG_ERROR, and LOG_INFO.
Referenced by ~LibraryManager(), loadLibrary(), and unloadLibrary().
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inline |
bool isc::hooks::LibraryManager::loadLibrary | ( | bool | multi_threading_enabled = false | ) |
Loads a library.
Open the library, check the version and the multi-threading compatibility. If all is OK, load all standard symbols then call "load" if present.
It also calls the isc::log::MessageInitializer::loadDictionary
, prior to invoking the version
function of the library, to update the global logging dictionary with the log messages registered by the loaded library.
multi_threading_enabled | The flag which indicates if MT is enabled (used to check hook libraries compatibility with MT). |
Definition at line 317 of file library_manager.cc.
References checkMultiThreadingCompatible(), checkVersion(), closeLibrary(), isc::hooks::HOOKS_DBG_TRACE, isc::hooks::HOOKS_LIBRARY_LOADED, isc::hooks::HOOKS_LIBRARY_LOADING, isc::hooks::hooks_logger, isc::log::MessageInitializer::loadDictionary(), LOG_DEBUG, LOG_INFO, isc::log::LoggerManager::logDuplicatedMessages(), openLibrary(), prepareUnloadLibrary(), registerStandardCallouts(), and runLoad().
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Open library.
Opens the library associated with this LibraryManager. A message is logged on an error.
Definition at line 72 of file library_manager.cc.
References isc::hooks::hooks_logger, isc::hooks::HOOKS_OPEN_ERROR, and LOG_ERROR.
Referenced by loadLibrary().
bool isc::hooks::LibraryManager::prepareUnloadLibrary | ( | ) |
Prepares library unloading.
Searches for the "unload" framework function and, if present, runs it. Regardless of status, remove all callouts associated with this library on all hooks.
Definition at line 247 of file library_manager.cc.
References isc::hooks::ServerHooks::getServerHooks(), isc::hooks::HOOKS_CALLOUTS_REMOVED, isc::hooks::HOOKS_DBG_CALLS, isc::hooks::HOOKS_DBG_TRACE, isc::hooks::hooks_logger, isc::hooks::HOOKS_NO_UNLOAD, isc::hooks::HOOKS_UNLOAD_ERROR, isc::hooks::HOOKS_UNLOAD_EXCEPTION, isc::hooks::HOOKS_UNLOAD_FRAMEWORK_EXCEPTION, isc::hooks::HOOKS_UNLOAD_SUCCESS, LOG_DEBUG, LOG_ERROR, and LOG_WARN.
Referenced by ~LibraryManager(), loadLibrary(), and unloadLibrary().
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Register standard callouts.
Loops through the list of hook names and searches the library for functions with those names. Any that are found are registered as callouts for that hook.
Definition at line 176 of file library_manager.cc.
References isc::hooks::ServerHooks::getServerHooks(), isc::hooks::HOOKS_DBG_CALLS, isc::hooks::hooks_logger, isc::hooks::HOOKS_STD_CALLOUT_REGISTERED, and LOG_DEBUG.
Referenced by loadLibrary().
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Run the load function if present.
Searches for the "load" framework function and, if present, runs it.
Definition at line 203 of file library_manager.cc.
References isc::hooks::HOOKS_DBG_TRACE, isc::hooks::HOOKS_LOAD_ERROR, isc::hooks::HOOKS_LOAD_EXCEPTION, isc::hooks::HOOKS_LOAD_FRAMEWORK_EXCEPTION, isc::hooks::HOOKS_LOAD_SUCCESS, isc::hooks::hooks_logger, isc::hooks::HOOKS_NO_LOAD, LOG_DEBUG, and LOG_ERROR.
Referenced by loadLibrary().
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Unloads a library.
Calls the libraries "unload" function if present, the closes the library.
However, see the caveat in the class header about when it is safe to unload libraries.
Definition at line 379 of file library_manager.cc.
References closeLibrary(), isc::hooks::HOOKS_DBG_TRACE, isc::hooks::HOOKS_LIBRARY_UNLOADED, isc::hooks::HOOKS_LIBRARY_UNLOADING, isc::hooks::hooks_logger, LOG_DEBUG, LOG_INFO, and prepareUnloadLibrary().
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static |
Validate library.
A static method that is used to validate a library. Validation checks that the library can be opened, that "version" exists, and that it returns the right number, and the multi-threading compatibility.
name | Name of the library to validate |
multi_threading_enabled | The flag which indicates if MT is enabled (used to check hook libraries compatibility with MT). |
Definition at line 410 of file library_manager.cc.
Referenced by isc::hooks::LibraryManagerCollection::validateLibraries().