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Diffstat (limited to 'kdecore/network/kresolvermanager.cpp')
| -rw-r--r-- | kdecore/network/kresolvermanager.cpp | 822 |
1 files changed, 0 insertions, 822 deletions
diff --git a/kdecore/network/kresolvermanager.cpp b/kdecore/network/kresolvermanager.cpp deleted file mode 100644 index b3c7172ae..000000000 --- a/kdecore/network/kresolvermanager.cpp +++ /dev/null @@ -1,822 +0,0 @@ -/* -*- C++ -*- - * Copyright (C) 2003-2005 Thiago Macieira <thiago.macieira@kdemail.net> - * - * - * Permission is hereby granted, free of charge, to any person obtaining - * a copy of this software and associated documentation files (the - * "Software"), to deal in the Software without restriction, including - * without limitation the rights to use, copy, modify, merge, publish, - * distribute, sublicense, and/or sell copies of the Software, and to - * permit persons to whom the Software is furnished to do so, subject to - * the following conditions: - * - * The above copyright notice and this permission notice shall be included - * in all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, - * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF - * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND - * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE - * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION - * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION - * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. - */ - -#include "config.h" - -#include <sys/types.h> -#include <netinet/in.h> -#include <limits.h> -#include <unistd.h> // only needed for pid_t - -#ifdef HAVE_RES_INIT -# include <sys/stat.h> -extern "C" { -# include <arpa/nameser.h> -} -# include <time.h> -# include <resolv.h> -#endif - -#include <tqapplication.h> -#include <tqstring.h> -#include <tqcstring.h> -#include <tqptrlist.h> -#include <tqtimer.h> -#include <tqmutex.h> -#include <tqthread.h> -#include <tqwaitcondition.h> -#include <tqsemaphore.h> - -#include <kde_file.h> -#include <kdebug.h> -#include "kresolver.h" -#include "kresolver_p.h" -#include "kresolverworkerbase.h" - -namespace KNetwork -{ - namespace Internal - { - void initSrvWorker(); - void initStandardWorkers(); - } -} - -using namespace KNetwork; -using namespace KNetwork::Internal; - -/* - * Explanation on how the resolver system works - - When KResolver::start is called, it calls KResolverManager::enqueue to add - an entry to the queue. KResolverManager::enqueue will verify the availability - of a worker thread: if one is available, it will dispatch the request to it. - If no threads are available, it will then decide whether to launch a thread - or to queue for the future. - - (This process is achieved by always queueing the new request, starting a - new thread if necessary and then notifying of the availability of data - to all worker threads). - - * Worker thread - A new thread, when started, will enter its event loop - immediately. That is, it'll first try to acquire new data to - process, which means it will lock and unlock the manager mutex in - the process. - - If it finds no new data, it'll wait on the feedWorkers condition - for a certain maximum time. If that time expires and there's still - no data, the thread will exit, in order to save system resources. - - If it finds data, however, it'll set up and call the worker class - that has been selected by the manager. Once that worker is done, - the thread releases the data through KResolverManager::releaseData. - - * Data requesting/releasing - A worker thread always calls upon functions on the resolver manager - in order to acquire and release data. - - When data is being requested, the KResolverManager::requestData - function will look the currentRequests list and return the first - Queued request it finds, while marking it to be InProgress. - - When the worker class has returned, the worker thread will release - that data through the KResolverManager::releaseData function. If the - worker class has requested no further data (nRequests == 0), the - request's status is marked to be Done. It'll then look at the - requestor for that data: if it was requested by another worker, - it'll decrement the requests count for that one and add the results - to a list. And, finally, if the requests count for the requestor - becomes 0, it'll repeat this process for the requestor as well - (change status to Done, check for a requestor). - */ - -namespace -{ - -/* - * This class is used to control the access to the - * system's resolver API. - * - * It is necessary to periodically poll /etc/resolv.conf and reload - * it if any changes are noticed. This class does exactly that. - * - * However, there's also the problem of reloading the structure while - * some threads are in progress. Therefore, we keep a usage reference count. - */ -class ResInitUsage -{ -public: - -#ifdef HAVE_RES_INIT - time_t mTime; - int useCount; - -# ifndef RES_INIT_THREADSAFE - TQWaitCondition cond; - TQMutex mutex; -# endif - - bool shouldResInit() - { - // check if /etc/resolv.conf has changed - KDE_struct_stat st; - if (KDE_stat("/etc/resolv.conf", &st) != 0) - return false; - - if (mTime != st.st_mtime) - { - kdDebug(179) << "shouldResInit: /etc/resolv.conf updated" << endl; - return true; - } - return false; - } - - void callResInit() - { - if (mTime != 0) - { - // don't call it the first time - // let it be initialised naturally - kdDebug(179) << "callResInit: calling res_init()" << endl; - res_init(); - } - - KDE_struct_stat st; - if (KDE_stat("/etc/resolv.conf", &st) == 0) - mTime = st.st_mtime; - } - - ResInitUsage() - : mTime(0), useCount(0) - { } - - /* - * Marks the end of usage to the resolver tools - */ - void release() - { -# ifndef RES_INIT_THREADSAFE - TQMutexLocker locker(&mutex); - if (--useCount == 0) - { - if (shouldResInit()) - callResInit(); - - // we've reached 0, wake up anyone that's waiting to call res_init - cond.wakeAll(); - } -# else - // do nothing -# endif - } - - /* - * Marks the beginning of usage of the resolver API - */ - void acquire() - { -# ifndef RES_INIT_THREADSAFE - mutex.lock(); - - if (shouldResInit()) - { - if (useCount) - { - // other threads are already using the API, so wait till - // it's all clear - // the thread that emits this condition will also call res_init - //qDebug("ResInitUsage: waiting for libresolv to be clear"); - cond.wait(&mutex); - } - else - // we're clear - callResInit(); - } - useCount++; - mutex.unlock(); - -# else - if (shouldResInit()) - callResInit(); - -# endif - } - -#else - ResInitUsage() - { } - - bool shouldResInit() - { return false; } - - void acquire() - { } - - void release() - { } -#endif - -} resInit; - -} // anonymous namespace - -/* - * parameters - */ -// a thread will try maxThreadRetries to get data, waiting at most -// maxThreadWaitTime milliseconds between each attempt. After that, it'll -// exit -static const int maxThreadWaitTime = 2000; // 2 seconds -static const int maxThreads = 5; - -static pid_t pid; // FIXME -- disable when everything is ok - -KResolverThread::KResolverThread() - : data(0L) -{ -} - -// remember! This function runs in a separate thread! -void KResolverThread::run() -{ - // initialisation - // enter the loop already - - //qDebug("KResolverThread(thread %u/%p): started", pid, (void*)TQThread::currentThread()); - KResolverManager::manager()->registerThread(this); - while (true) - { - data = KResolverManager::manager()->requestData(this, ::maxThreadWaitTime); - //qDebug("KResolverThread(thread %u/%p) got data %p", KResolverManager::pid, - // (void*)TQThread::currentThread(), (void*)data); - if (data) - { - // yes, we got data - // process it! - - // 1) set up - ; - - // 2) run it - data->worker->run(); - - // 3) release data - KResolverManager::manager()->releaseData(this, data); - - // now go back to the loop - } - else - break; - } - - KResolverManager::manager()->unregisterThread(this); - //qDebug("KResolverThread(thread %u/%p): exiting", pid, (void*)TQThread::currentThread()); -} - -bool KResolverThread::checkResolver() -{ - return resInit.shouldResInit(); -} - -void KResolverThread::acquireResolver() -{ -#if defined(NEED_MUTEX) && !defined(Q_OS_FREEBSD) - getXXbyYYmutex.lock(); -#endif - - resInit.acquire(); -} - -void KResolverThread::releaseResolver() -{ -#if defined(NEED_MUTEX) && !defined(Q_OS_FREEBSD) - getXXbyYYmutex.unlock(); -#endif - - resInit.release(); -} - -static KResolverManager *globalManager; - -KResolverManager* KResolverManager::manager() -{ - if (globalManager == 0L) - new KResolverManager(); - return globalManager; -} - -KResolverManager::KResolverManager() - : runningThreads(0), availableThreads(0) -{ - globalManager = this; - workers.setAutoDelete(true); - currentRequests.setAutoDelete(true); - initSrvWorker(); - initStandardWorkers(); - - pid = getpid(); -} - -KResolverManager::~KResolverManager() -{ - // this should never be called - - // kill off running threads - for (workers.first(); workers.current(); workers.next()) - workers.current()->terminate(); -} - -void KResolverManager::registerThread(KResolverThread* ) -{ -} - -void KResolverManager::unregisterThread(KResolverThread*) -{ - runningThreads--; -} - -// this function is called by KResolverThread::run -RequestData* KResolverManager::requestData(KResolverThread *th, int maxWaitTime) -{ - ///// - // This function is called in a worker thread!! - ///// - - // lock the mutex, so that the manager thread or other threads won't - // interfere. - TQMutexLocker locker(&mutex); - RequestData *data = findData(th); - - if (data) - // it found something, that's good - return data; - - // nope, nothing found; sleep for a while - availableThreads++; - feedWorkers.wait(&mutex, maxWaitTime); - availableThreads--; - - data = findData(th); - return data; -} - -RequestData* KResolverManager::findData(KResolverThread* th) -{ - ///// - // This function is called by @ref requestData above and must - // always be called with a locked mutex - ///// - - // now find data to be processed - for (RequestData *curr = newRequests.first(); curr; curr = newRequests.next()) - if (!curr->worker->m_finished) - { - // found one - if (curr->obj) - curr->obj->status = KResolver::InProgress; - curr->worker->th = th; - - // move it to the currentRequests list - currentRequests.append(newRequests.take()); - - return curr; - } - - // found nothing! - return 0L; -} - -// this function is called by KResolverThread::run -void KResolverManager::releaseData(KResolverThread *, RequestData* data) -{ - ///// - // This function is called in a worker thread!! - ///// - - //qDebug("KResolverManager::releaseData(%u/%p): %p has been released", pid, -// (void*)TQThread::currentThread(), (void*)data); - - if (data->obj) - { - data->obj->status = KResolver::PostProcessing; - } - - data->worker->m_finished = true; - data->worker->th = 0L; // this releases the object - - // handle finished requests - handleFinished(); -} - -// this function is called by KResolverManager::releaseData above -void KResolverManager::handleFinished() -{ - bool redo = false; - TQPtrQueue<RequestData> doneRequests; - - mutex.lock(); - - // loop over all items on the currently running list - // we loop from the last to the first so that we catch requests with "requestors" before - // we catch the requestor itself. - RequestData *curr = currentRequests.last(); - while (curr) - { - if (curr->worker->th == 0L) - { - if (handleFinishedItem(curr)) - { - doneRequests.enqueue(currentRequests.take()); - if (curr->requestor && - curr->requestor->nRequests == 0 && - curr->requestor->worker->m_finished) - // there's a requestor that is now finished - redo = true; - } - } - - curr = currentRequests.prev(); - } - - //qDebug("KResolverManager::handleFinished(%u): %d requests to notify", pid, doneRequests.count()); - while (RequestData *d = doneRequests.dequeue()) - doNotifying(d); - - mutex.unlock(); - - if (redo) - { - //qDebug("KResolverManager::handleFinished(%u): restarting processing to catch requestor", - // pid); - handleFinished(); - } -} - -// This function is called by KResolverManager::handleFinished above -bool KResolverManager::handleFinishedItem(RequestData* curr) - -{ - // for all items that aren't currently running, remove from the list - // this includes all finished or cancelled requests - - if (curr->worker->m_finished && curr->nRequests == 0) - { - // this one has finished - if (curr->obj) - curr->obj->status = KResolver::PostProcessing; // post-processing is run in doNotifying() - - if (curr->requestor) - --curr->requestor->nRequests; - - //qDebug("KResolverManager::handleFinishedItem(%u): removing %p since it's done", - // pid, (void*)curr); - return true; - } - return false; -} - - - -void KResolverManager::registerNewWorker(KResolverWorkerFactoryBase *factory) -{ - workerFactories.append(factory); -} - -KResolverWorkerBase* KResolverManager::findWorker(KResolverPrivate* p) -{ - ///// - // this function can be called on any user thread - ///// - - // this function is called with an unlocked mutex and it's expected to be - // thread-safe! - // but the factory list is expected not to be changed asynchronously - - // This function is responsible for finding a suitable worker for the given - // input. That means we have to do a costly operation to create each worker - // class and call their preprocessing functions. The first one that - // says they can process (i.e., preprocess() returns true) will get the job. - - KResolverWorkerBase *worker; - for (KResolverWorkerFactoryBase *factory = workerFactories.first(); factory; - factory = workerFactories.next()) - { - worker = factory->create(); - - // set up the data the worker needs to preprocess - worker->input = &p->input; - - if (worker->preprocess()) - { - // good, this one says it can process - if (worker->m_finished) - p->status = KResolver::PostProcessing; - else - p->status = KResolver::Queued; - return worker; - } - - // no, try again - delete worker; - } - - // found no worker - return 0L; -} - -void KResolverManager::doNotifying(RequestData *p) -{ - ///// - // This function may be called on any thread - // any thread at all: user threads, GUI thread, manager thread or worker thread - ///// - - // Notification and finalisation - // - // Once a request has finished the normal processing, we call the - // post processing function. - // - // After that is done, we will consolidate all results in the object's - // KResolverResults and then post an event indicating that the signal - // be emitted - // - // In case we detect that the object is waiting for completion, we do not - // post the event, for KResolver::wait will take care of emitting the - // signal. - // - // Once we release the mutex on the object, we may no longer reference it - // for it might have been deleted. - - // "User" objects are those that are not created by the manager. Note that - // objects created by worker threads are considered "user" objects. Objects - // created by the manager are those created for KResolver::resolveAsync. - // We should delete them. - - if (p->obj) - { - // lock the object - p->obj->mutex.lock(); - KResolver* parent = p->obj->parent; // is 0 for non-"user" objects - KResolverResults& r = p->obj->results; - - if (p->obj->status == KResolver::Canceled) - { - p->obj->status = KResolver::Canceled; - p->obj->errorcode = KResolver::Canceled; - p->obj->syserror = 0; - r.setError(KResolver::Canceled, 0); - } - else if (p->worker) - { - // post processing - p->worker->postprocess(); // ignore the result - - // copy the results from the worker thread to the final - // object - r = p->worker->results; - - // reset address - r.setAddress(p->input->node, p->input->service); - - //qDebug("KResolverManager::doNotifying(%u/%p): for %p whose status is %d and has %d results", - //pid, (void*)TQThread::currentThread(), (void*)p, p->obj->status, r.count()); - - p->obj->errorcode = r.error(); - p->obj->syserror = r.systemError(); - p->obj->status = !r.isEmpty() ? - KResolver::Success : KResolver::Failed; - } - else - { - r.empty(); - r.setError(p->obj->errorcode, p->obj->syserror); - } - - // check whether there's someone waiting - if (!p->obj->waiting && parent) - // no, so we must post an event requesting that the signal be emitted - // sorry for the C-style cast, but neither static nor reintepret cast work - // here; I'd have to do two casts - TQApplication::postEvent(parent, new TQEvent((TQEvent::Type)(ResolutionCompleted))); - - // release the mutex - p->obj->mutex.unlock(); - } - else - { - // there's no object! - if (p->worker) - p->worker->postprocess(); - } - - delete p->worker; - - // ignore p->requestor and p->nRequests - // they have been dealt with by the main loop - - delete p; - - // notify any objects waiting in KResolver::wait - notifyWaiters.wakeAll(); -} - -// enqueue a new request -// this function is called from KResolver::start and -// from KResolverWorkerBase::enqueue -void KResolverManager::enqueue(KResolver *obj, RequestData *requestor) -{ - RequestData *newrequest = new RequestData; - newrequest->nRequests = 0; - newrequest->obj = obj->d; - newrequest->input = &obj->d->input; - newrequest->requestor = requestor; - - // when processing a new request, find the most - // suitable worker - if ((newrequest->worker = findWorker(obj->d)) == 0L) - { - // oops, problem - // cannot find a worker class for this guy - obj->d->status = KResolver::Failed; - obj->d->errorcode = KResolver::UnsupportedFamily; - obj->d->syserror = 0; - - doNotifying(newrequest); - return; - } - - // no, queue it - // p->status was set in findWorker! - if (requestor) - requestor->nRequests++; - - if (!newrequest->worker->m_finished) - dispatch(newrequest); - else if (newrequest->nRequests > 0) - { - mutex.lock(); - currentRequests.append(newrequest); - mutex.unlock(); - } - else - // already done - doNotifying(newrequest); -} - -// a new request has been created -// dispatch it -void KResolverManager::dispatch(RequestData *data) -{ - // As stated in the beginning of the file, this function - // is supposed to verify the availability of threads, start - // any if necessary - - TQMutexLocker locker(&mutex); - - // add to the queue - newRequests.append(data); - - // check if we need to start a new thread - // - // we depend on the variables availableThreads and runningThreads to - // know if we are supposed to start any threads: - // - if availableThreads > 0, then there is at least one thread waiting, - // blocked in KResolverManager::requestData. It can't unblock - // while we are holding the mutex locked, therefore we are sure that - // our event will be handled - // - if availableThreads == 0: - // - if runningThreads < maxThreads - // we will start a new thread, which will certainly block in - // KResolverManager::requestData because we are holding the mutex locked - // - if runningThreads == maxThreads - // This situation generally means that we have already maxThreads running - // and that all of them are processing. We will not start any new threads, - // but will instead wait for one to finish processing and request new data - // - // There's a possible race condition here, which goes unhandled: if one of - // threads has timed out waiting for new data and is in the process of - // exiting. In that case, availableThreads == 0 and runningThreads will not - // have decremented yet. This means that we will not start a new thread - // that we could have. However, since there are other threads working, our - // event should be handled soon. - // It won't be handled if and only if ALL threads are in the process of - // exiting. That situation is EXTREMELY unlikely and is not handled either. - // - if (availableThreads == 0 && runningThreads < maxThreads) - { - // yes, a new thread should be started - - // find if there's a finished one - KResolverThread *th = workers.first(); - while (th && th->running()) - th = workers.next(); - - if (th == 0L) - // no, create one - th = new KResolverThread; - else - workers.take(); - - th->start(); - workers.append(th); - runningThreads++; - } - - feedWorkers.wakeAll(); - - // clean up idle threads - workers.first(); - while (workers.current()) - { - if (!workers.current()->running()) - workers.remove(); - else - workers.next(); - } -} - -// this function is called by KResolverManager::dequeue -bool KResolverManager::dequeueNew(KResolver* obj) -{ - // This function must be called with a locked mutex - // Deadlock warning: - // always lock the global mutex first if both mutexes must be locked - - KResolverPrivate *d = obj->d; - - // check if it's in the new request list - RequestData *curr = newRequests.first(); - while (curr) - if (curr->obj == d) - { - // yes, this object is still in the list - // but it has never been processed - d->status = KResolver::Canceled; - d->errorcode = KResolver::Canceled; - d->syserror = 0; - newRequests.take(); - - delete curr->worker; - delete curr; - - return true; - } - else - curr = newRequests.next(); - - // check if it's running - curr = currentRequests.first(); - while (curr) - if (curr->obj == d) - { - // it's running. We cannot simply take it out of the list. - // it will be handled when the thread that is working on it finishes - d->mutex.lock(); - - d->status = KResolver::Canceled; - d->errorcode = KResolver::Canceled; - d->syserror = 0; - - // disengage from the running threads - curr->obj = 0L; - curr->input = 0L; - if (curr->worker) - curr->worker->input = 0L; - - d->mutex.unlock(); - } - else - curr = currentRequests.next(); - - return false; -} - -// this function is called by KResolver::cancel -// it's expected to be thread-safe -void KResolverManager::dequeue(KResolver *obj) -{ - TQMutexLocker locker(&mutex); - dequeueNew(obj); -} |