4 // Fraunhofer Institute for Open Communication Systems (FOKUS)
5 // Competence Center NETwork research (NET), St. Augustin, GERMANY
6 // Stefan Bund <g0dil@berlios.de>
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 2 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the
20 // Free Software Foundation, Inc.,
21 // 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24 \brief Scheduler non-inline non-template implementation
26 \idea Multithreading support: To support multithreading, the
27 static member Scheduler::instance() must return a thread-local
28 value (that is Scheduler::instance() must allocate one Scheduler
29 instance per thread). Another possibility would be to distribute
30 the async load unto several threads (one scheduler for multiple
34 // Here a basic concept of how to add signal support to the scheduler:
36 // ... no, I had overlooked one race condition. So back to the signal-pipe approach ...
38 #include "Scheduler.hh"
39 //#include "Scheduler.ih"
42 #include "../Utils/senfassert.hh"
44 #include <sys/epoll.h>
47 #include "../Utils/Exception.hh"
49 static const int EPollInitialSize = 16;
52 ///////////////////////////////cc.p////////////////////////////////////////
54 prefix_ senf::Scheduler::Scheduler()
55 : files_(0), timerIdCounter_(0), epollFd_ (epoll_create(EPollInitialSize)), terminate_(false),
56 eventTime_(0), eventEarly_(ClockService::milliseconds(11)), eventAdjust_(0)
59 SENF_THROW_SYSTEM_EXCEPTION("");
61 if (::pipe(sigpipe_) < 0)
62 SENF_THROW_SYSTEM_EXCEPTION("");
64 int flags (::fcntl(sigpipe_[1],F_GETFL));
66 SENF_THROW_SYSTEM_EXCEPTION("");
68 if (::fcntl(sigpipe_[1], F_SETFL, flags) < 0)
69 SENF_THROW_SYSTEM_EXCEPTION("");
72 ::memset(&ev, 0, sizeof(ev));
74 ev.data.fd = sigpipe_[0];
75 if (::epoll_ctl(epollFd_, EPOLL_CTL_ADD, sigpipe_[0], &ev) < 0)
76 SENF_THROW_SYSTEM_EXCEPTION("");
79 prefix_ void senf::Scheduler::registerSignal(unsigned signal, SimpleCallback const & cb)
83 if (::sigaddset(&sig, signal) < 0)
84 throw InvalidSignalNumberException();
85 ::sigprocmask(SIG_BLOCK, &sig, 0);
86 ::sigaddset(&sigset_, signal);
87 if (sigHandlers_.size() <= signal)
88 sigHandlers_.resize(signal+1);
89 sigHandlers_[signal] = cb;
91 registerSigHandlers();
94 prefix_ void senf::Scheduler::unregisterSignal(unsigned signal)
96 if (::sigdelset(&sigset_, signal) < 0)
97 throw InvalidSignalNumberException();
98 sigHandlers_[signal] = 0;
99 ::signal(signal, SIG_DFL);
100 registerSigHandlers();
103 prefix_ void senf::Scheduler::do_add(int fd, FdCallback const & cb, int eventMask)
108 FdTable::iterator i (fdTable_.find(fd));
109 int action (EPOLL_CTL_MOD);
110 if (i == fdTable_.end()) {
111 action = EPOLL_CTL_ADD;
112 i = fdTable_.insert(std::make_pair(fd, EventSpec())).first;
114 if (i->second.epollMask() == 0) {
115 action = EPOLL_CTL_ADD;
116 fdErase_.erase( std::remove(fdErase_.begin(), fdErase_.end(), unsigned(fd)),
120 if (eventMask & EV_READ) i->second.cb_read = cb;
121 if (eventMask & EV_PRIO) i->second.cb_prio = cb;
122 if (eventMask & EV_WRITE) i->second.cb_write = cb;
125 memset(&ev,0,sizeof(ev));
126 ev.events = i->second.epollMask();
129 if (! i->second.file && epoll_ctl(epollFd_, action, fd, &ev) < 0) {
130 if (errno == EPERM) {
131 // Argh ... epoll does not support ordinary files :-( :-(
132 i->second.file = true;
136 SENF_THROW_SYSTEM_EXCEPTION("::epoll_ctl()");
140 prefix_ void senf::Scheduler::do_remove(int fd, int eventMask)
145 FdTable::iterator i (fdTable_.find(fd));
146 if (i == fdTable_.end())
149 if (eventMask & EV_READ) i->second.cb_read = 0;
150 if (eventMask & EV_PRIO) i->second.cb_prio = 0;
151 if (eventMask & EV_WRITE) i->second.cb_write = 0;
154 memset(&ev,0,sizeof(ev));
155 ev.events = i->second.epollMask();
158 int action (EPOLL_CTL_MOD);
159 bool file (i->second.file);
161 action = EPOLL_CTL_DEL;
162 fdErase_.push_back(fd);
165 if (! file && epoll_ctl(epollFd_, action, fd, &ev) < 0)
166 SENF_THROW_SYSTEM_EXCEPTION("::epoll_ctl()");
171 prefix_ void senf::Scheduler::registerSigHandlers()
173 for (unsigned signal (1); signal < sigHandlers_.size(); ++signal) {
174 if (sigHandlers_[signal]) {
175 struct ::sigaction sa;
176 sa.sa_sigaction = & Scheduler::sigHandler;
177 sa.sa_mask = sigset_;
178 sa.sa_flags = SA_SIGINFO;
179 if (signal == SIGCHLD)
180 sa.sa_flags |= SA_NOCLDSTOP;
181 if (::sigaction(signal, &sa, 0) < 0)
182 SENF_THROW_SYSTEM_EXCEPTION("");
187 prefix_ void senf::Scheduler::sigHandler(int signal, ::siginfo_t * siginfo, void *)
189 // This is a bit unsafe. Better write single bytes and place the siginfo into an explicit
190 // queue. Since signals are only unblocked during epoll_wait, we even wouldn't need to
191 // synchronize access to that queue any further.
193 ::write(instance().sigpipe_[1], siginfo, sizeof(*siginfo));
195 // We ignore errors. The file handle is set to non-blocking IO. If any failure occurs (pipe
196 // full), the signal will be dropped. That's like kernel signal handling which may also drop
200 prefix_ int senf::Scheduler::EventSpec::epollMask()
204 if (cb_read) mask |= EPOLLIN;
205 if (cb_prio) mask |= EPOLLPRI;
206 if (cb_write) mask |= EPOLLOUT;
210 prefix_ void senf::Scheduler::process()
213 eventTime_ = ClockService::now();
214 while (! terminate_) {
216 // Since a callback may have disabled further timers, we need to check for canceled timeouts
219 while (! timerQueue_.empty()) {
220 TimerMap::iterator i (timerQueue_.top());
221 if (! i->second.canceled)
227 for (FdEraseList::iterator i (fdErase_.begin()); i != fdErase_.end(); ++i)
235 if (timerQueue_.empty()) {
236 if (fdTable_.empty())
240 ClockService::clock_type delta (
241 (timerQueue_.top()->second.timeout - eventTime_ + eventAdjust_)/1000000UL);
242 timeout = delta < 0 ? 0 : delta;
246 ///\todo Handle more than one epoll_event per call
247 struct epoll_event ev;
249 ::sigprocmask(SIG_UNBLOCK, &sigset_, 0);
250 int events (epoll_wait(epollFd_, &ev, 1, timeout));
251 ::sigprocmask(SIG_BLOCK, &sigset_, 0);
255 SENF_THROW_SYSTEM_EXCEPTION("");
257 eventTime_ = ClockService::now();
259 // We always run timeout handlers. This is important, even if a file-descriptor is signaled
260 // since some descriptors (e.g. real files) will *always* be ready and we still may want to
261 // handle timers. Time handlers are run before file events to not delay them unnecessarily.
263 while (! timerQueue_.empty()) {
264 TimerMap::iterator i (timerQueue_.top());
265 if (i->second.canceled)
267 else if (i->second.timeout <= eventTime_ + eventEarly_)
275 // Check the signal queue
276 if (events > 0 && ev.data.fd == sigpipe_[0]) {
278 if (::read(sigpipe_[0], &siginfo, sizeof(siginfo)) < int(sizeof(siginfo))) {
279 // We ignore truncated records which may only occur if the signal
280 // queue became filled up
281 SENF_LOG((senf::log::IMPORTANT)("Truncated signal record!"));
284 if (siginfo.si_signo < int(sigHandlers_.size()) && sigHandlers_[siginfo.si_signo])
285 sigHandlers_[siginfo.si_signo]();
289 for (FdTable::iterator i = fdTable_.begin(); i != fdTable_.end(); ++i) {
290 EventSpec & spec (i->second);
292 if (! (spec.file || (events > 0 && i->first == ev.data.fd)))
295 unsigned extraFlags (0);
296 unsigned mask (spec.file ? spec.epollMask() : ev.events);
298 if (mask & EPOLLHUP) extraFlags |= EV_HUP;
299 if (mask & EPOLLERR) extraFlags |= EV_ERR;
301 if (mask & EPOLLIN) {
302 SENF_ASSERT(spec.cb_read);
303 spec.cb_read(EventId(EV_READ | extraFlags));
305 else if (mask & EPOLLPRI) {
306 SENF_ASSERT(spec.cb_prio);
307 spec.cb_prio(EventId(EV_PRIO | extraFlags));
309 else if (mask & EPOLLOUT) {
310 SENF_ASSERT(spec.cb_write);
311 spec.cb_write(EventId(EV_WRITE | extraFlags));
314 // This branch is only taken, if HUP or ERR is signaled but none of IN/OUT/PRI.
315 // In this case we will signal all registered callbacks. The callbacks must be
316 // prepared to be called multiple times if they are registered to more than
319 spec.cb_write(EventId(extraFlags));
321 spec.cb_prio(EventId(extraFlags));
323 spec.cb_read(EventId(extraFlags));
329 ///////////////////////////////////////////////////////////////////////////
330 // senf::SchedulerLogTimeSource
332 prefix_ boost::posix_time::ptime senf::SchedulerLogTimeSource::operator()()
335 return ClockService::abstime(Scheduler::instance().eventTime());
338 ///////////////////////////////cc.e////////////////////////////////////////
345 // c-file-style: "senf"
346 // indent-tabs-mode: nil
347 // ispell-local-dictionary: "american"
348 // compile-command: "scons -u test"
349 // comment-column: 40