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diff --git a/kdecore/network/kresolvermanager.cpp b/kdecore/network/kresolvermanager.cpp
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+/* -*- 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 <qapplication.h>
+#include <qstring.h>
+#include <qcstring.h>
+#include <qptrlist.h>
+#include <qtimer.h>
+#include <qmutex.h>
+#include <qthread.h>
+#include <qwaitcondition.h>
+#include <qsemaphore.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
+ QWaitCondition cond;
+ QMutex 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
+ QMutexLocker 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*)QThread::currentThread());
+ KResolverManager::manager()->registerThread(this);
+ while (true)
+ {
+ data = KResolverManager::manager()->requestData(this, ::maxThreadWaitTime);
+ //qDebug("KResolverThread(thread %u/%p) got data %p", KResolverManager::pid,
+ // (void*)QThread::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*)QThread::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.
+ QMutexLocker 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*)QThread::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;
+ QPtrQueue<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*)QThread::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
+ QApplication::postEvent(parent, new QEvent((QEvent::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
+
+ QMutexLocker 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)
+{
+ QMutexLocker locker(&mutex);
+ dequeueNew(obj);
+}
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