4 // Fraunhofer Institut fuer offene Kommunikationssysteme (FOKUS)
5 // Kompetenzzentrum fuer Satelitenkommunikation (SatCom)
6 // Stefan Bund <stefan.bund@fokus.fraunhofer.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 Implement signal handling (See source for more discussion
29 \idea Multithreading support: To support multithreading, the
30 static member Scheduler::instance() must return a thread-local
31 value (that is Scheduler::instance() must allocate one Scheduler
32 instance per thread). Another possibility would be to distribute
33 the async load unto several threads (one scheduler for multiple
37 // Here a basic concept of how to add signal support to the scheduler:
39 // ... no, I had overlooked one race condition. So back to the signal-pipe approach ...
41 #include "Scheduler.hh"
42 //#include "Scheduler.ih"
46 #include <sys/epoll.h>
49 #include "../Utils/Exception.hh"
51 static const int EPollInitialSize = 16;
54 ///////////////////////////////cc.p////////////////////////////////////////
56 prefix_ senf::Scheduler::Scheduler()
57 : timerIdCounter_(0), epollFd_ (epoll_create(EPollInitialSize)), terminate_(false),
58 eventTime_(0), eventEarly_(ClockService::milliseconds(11)), eventAdjust_(0)
61 throw SystemException(errno);
63 if (::pipe(sigpipe_) < 0)
64 throw SystemException(errno);
66 int flags (::fcntl(sigpipe_[1],F_GETFL));
68 throw SystemException(errno);
70 if (::fcntl(sigpipe_[1], F_SETFL, flags) < 0)
71 throw SystemException(errno);
74 ::memset(&ev, 0, sizeof(ev));
76 ev.data.fd = sigpipe_[0];
77 if (::epoll_ctl(epollFd_, EPOLL_CTL_ADD, sigpipe_[0], &ev) < 0)
78 throw SystemException(errno);
81 prefix_ void senf::Scheduler::registerSignal(unsigned signal, SimpleCallback const & cb)
85 if (::sigaddset(&sig, signal) < 0)
86 throw InvalidSignalNumberException();
87 ::sigprocmask(SIG_BLOCK, &sig, 0);
88 ::sigaddset(&sigset_, signal);
89 if (sigHandlers_.size() <= signal)
90 sigHandlers_.resize(signal+1);
91 sigHandlers_[signal] = cb;
93 registerSigHandlers();
96 prefix_ void senf::Scheduler::unregisterSignal(unsigned signal)
98 if (::sigdelset(&sigset_, signal) < 0)
99 throw InvalidSignalNumberException();
100 sigHandlers_[signal] = 0;
101 ::signal(signal, SIG_DFL);
102 registerSigHandlers();
105 prefix_ void senf::Scheduler::do_add(int fd, FdCallback const & cb, int eventMask)
107 FdTable::iterator i (fdTable_.find(fd));
108 int action (EPOLL_CTL_MOD);
109 if (i == fdTable_.end()) {
110 action = EPOLL_CTL_ADD;
111 i = fdTable_.insert(std::make_pair(fd, EventSpec())).first;
114 if (eventMask & EV_READ) i->second.cb_read = cb;
115 if (eventMask & EV_PRIO) i->second.cb_prio = cb;
116 if (eventMask & EV_WRITE) i->second.cb_write = cb;
119 memset(&ev,0,sizeof(ev));
120 ev.events = i->second.epollMask();
123 if (epoll_ctl(epollFd_, action, fd, &ev)<0)
124 throw SystemException(errno);
127 prefix_ void senf::Scheduler::do_remove(int fd, int eventMask)
129 FdTable::iterator i (fdTable_.find(fd));
130 if (i == fdTable_.end())
133 if (eventMask & EV_READ) i->second.cb_read = 0;
134 if (eventMask & EV_PRIO) i->second.cb_prio = 0;
135 if (eventMask & EV_WRITE) i->second.cb_write = 0;
138 memset(&ev,0,sizeof(ev));
139 ev.events = i->second.epollMask();
142 int action (EPOLL_CTL_MOD);
144 action = EPOLL_CTL_DEL;
148 if (epoll_ctl(epollFd_, action, fd, &ev)<0)
149 throw SystemException(errno);
152 prefix_ void senf::Scheduler::registerSigHandlers()
154 for (unsigned signal; signal < sigHandlers_.size(); ++signal)
155 if (sigHandlers_[signal]) {
156 struct ::sigaction sa;
157 sa.sa_sigaction = & Scheduler::sigHandler;
158 sa.sa_mask = sigset_;
159 sa.sa_flags = SA_SIGINFO;
160 if (signal == SIGCHLD)
161 sa.sa_flags |= SA_NOCLDSTOP;
162 if (::sigaction(signal, &sa, 0) < 0)
163 throw SystemException(errno);
167 prefix_ void senf::Scheduler::sigHandler(int signal, ::siginfo_t * siginfo, void *)
169 // This is a bit unsafe. Better write single bytes and place the siginfo into an explicit
170 // queue. Since signals are only unblocked during epoll_wait, we even wouldn't need to
171 // synchronize access to that queue any further.
173 ::write(instance().sigpipe_[1], siginfo, sizeof(siginfo));
175 // We ignore errors. The file handle is set to non-blocking IO. If any failure occurs (pipe
176 // full), the signal will be dropped. That's like kernel signal handling which may also drop
180 prefix_ int senf::Scheduler::EventSpec::epollMask()
184 if (cb_read) mask |= EPOLLIN;
185 if (cb_prio) mask |= EPOLLPRI;
186 if (cb_write) mask |= EPOLLOUT;
190 prefix_ void senf::Scheduler::process()
193 eventTime_ = ClockService::now();
194 while (! terminate_) {
196 // Since a callback may have disabled further timers, we need to check for canceled timeouts
199 while (! timerQueue_.empty()) {
200 TimerMap::iterator i (timerQueue_.top());
201 if (! i->second.canceled)
208 if (timerQueue_.empty()) {
209 if (fdTable_.empty())
213 ClockService::clock_type delta (
214 (timerQueue_.top()->second.timeout - eventTime_ + eventAdjust_)/1000000UL);
215 timeout = delta < 0 ? 0 : delta;
218 ///\todo Handle more than one epoll_event per call
219 struct epoll_event ev;
221 ::sigprocmask(SIG_UNBLOCK, &sigset_, 0);
222 int events (epoll_wait(epollFd_, &ev, 1, timeout));
223 ::sigprocmask(SIG_BLOCK, &sigset_, 0);
227 throw SystemException(errno);
229 eventTime_ = ClockService::now();
231 // We always run timeout handlers. This is important, even if a file-descriptor is signaled
232 // since some descriptors (e.g. real files) will *always* be ready and we still may want to
233 // handle timers. Time handlers are run before file events to not delay them unnecessarily.
235 while (! timerQueue_.empty()) {
236 TimerMap::iterator i (timerQueue_.top());
237 if (i->second.canceled)
239 else if (i->second.timeout <= eventTime_ + eventEarly_)
250 // Check the signal queue
251 if (ev.data.fd == sigpipe_[0]) {
253 if (::read(sigpipe_[0], &siginfo, sizeof(siginfo)) < int(sizeof(siginfo)))
254 // We ignore truncated records which may only occur if the signal
255 // queue became filled up
257 if (siginfo.si_signo < int(sigHandlers_.size()) && sigHandlers_[siginfo.si_signo])
258 sigHandlers_[siginfo.si_signo]();
262 FdTable::iterator i = fdTable_.find(ev.data.fd);
263 BOOST_ASSERT (i != fdTable_.end() );
264 EventSpec spec (i->second);
266 unsigned extraFlags (0);
267 if (ev.events & EPOLLHUP) extraFlags |= EV_HUP;
268 if (ev.events & EPOLLERR) extraFlags |= EV_ERR;
270 if (ev.events & EPOLLIN) {
271 BOOST_ASSERT(spec.cb_read);
272 spec.cb_read(EventId(EV_READ | extraFlags));
274 else if (ev.events & EPOLLPRI) {
275 BOOST_ASSERT(spec.cb_prio);
276 spec.cb_prio(EventId(EV_PRIO | extraFlags));
278 else if (ev.events & EPOLLOUT) {
279 BOOST_ASSERT(spec.cb_write);
280 spec.cb_write(EventId(EV_WRITE | extraFlags));
283 // This branch is only taken, if HUP or ERR is signaled but none of IN/OUT/PRI.
284 // In this case we will signal all registered callbacks. The callbacks must be
285 // prepared to be called multiple times if they are registered to more than
288 spec.cb_write(EventId(extraFlags));
290 spec.cb_prio(EventId(extraFlags));
292 spec.cb_read(EventId(extraFlags));
297 ///////////////////////////////////////////////////////////////////////////
298 // senf::SchedulerLogTimeSource
300 prefix_ boost::posix_time::ptime senf::SchedulerLogTimeSource::operator()()
303 return ClockService::abstime(Scheduler::instance().eventTime());
306 ///////////////////////////////cc.e////////////////////////////////////////
313 // c-file-style: "senf"
314 // indent-tabs-mode: nil
315 // ispell-local-dictionary: "american"
316 // compile-command: "scons -u test"
317 // comment-column: 40