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 // Every signal to be reported by the scheduler will be asigned a
40 // generic signal handler by the scheduler. This signal handler will
41 // use longjmp (juck) to report this signal back to the scheduler
44 // To make this safe, the main-loop will look something like:
46 // int signal = setjmp(jmpBuffer_);
48 // // unblock all signals which are registered with the
51 // // block all relevant signals again
54 // // now handle the event
56 // The signal handler is then simply defined as
58 // static void Scheduler::sigHandler(int signal)
60 // // make sure to restore the signal handler here if
62 // longjmp(Scheduler::instance().jmpBuffer_,signal);
65 // You should use sigaction to register the signal handlers and define
66 // a sa_mask so all Scheduler-registered signals are automatically
67 // *blocked* whenever one of the signals is called (including the
68 // called signal!) (This also means, we will have to re-register all
69 // signals if we change the registration of some signal since the
70 // sa_mask changes). This ensures, that no two signals can be
71 // delivered on top of each other. And of course any signal registered
72 // with the scheduler must be blocked as soon as it is registered with
75 #include "Scheduler.hh"
76 //#include "Scheduler.ih"
80 #include <sys/epoll.h>
81 #include "Utils/Exception.hh"
82 #include "Utils/MicroTime.hh"
84 static const int EPollInitialSize = 16;
87 ///////////////////////////////cc.p////////////////////////////////////////
89 prefix_ senf::Scheduler::Scheduler & senf::Scheduler::instance()
91 static Scheduler instance;
95 prefix_ void senf::Scheduler::timeout(unsigned long timeout, TimerCallback const & cb)
97 timerQueue_.push(TimerSpec(now()+1000*timeout,cb));
100 prefix_ senf::Scheduler::Scheduler()
101 : epollFd_(epoll_create(EPollInitialSize))
104 throw SystemException(errno);
107 prefix_ void senf::Scheduler::do_add(int fd, SimpleCallback const & cb, int eventMask)
109 FdTable::iterator i (fdTable_.find(fd));
110 int action (EPOLL_CTL_MOD);
111 if (i == fdTable_.end()) {
112 action = EPOLL_CTL_ADD;
113 i = fdTable_.insert(std::make_pair(fd, EventSpec())).first;
116 if (eventMask & EV_READ) i->second.cb_read = cb;
117 if (eventMask & EV_PRIO) i->second.cb_prio = cb;
118 if (eventMask & EV_WRITE) i->second.cb_write = cb;
121 memset(&ev,0,sizeof(ev));
122 ev.events = i->second.epollMask();
125 if (epoll_ctl(epollFd_, action, fd, &ev)<0)
126 throw SystemException(errno);
129 prefix_ void senf::Scheduler::do_remove(int fd, int eventMask)
131 FdTable::iterator i (fdTable_.find(fd));
132 if (i == fdTable_.end())
135 if (eventMask & EV_READ) i->second.cb_read = 0;
136 if (eventMask & EV_PRIO) i->second.cb_prio = 0;
137 if (eventMask & EV_WRITE) i->second.cb_write = 0;
140 memset(&ev,0,sizeof(ev));
141 ev.events = i->second.epollMask();
144 int action (EPOLL_CTL_MOD);
146 action = EPOLL_CTL_DEL;
150 if (epoll_ctl(epollFd_, action, fd, &ev)<0)
151 throw SystemException(errno);
155 prefix_ int senf::Scheduler::EventSpec::epollMask()
159 if (cb_read) mask |= EPOLLIN;
160 if (cb_prio) mask |= EPOLLPRI;
161 if (cb_write) mask |= EPOLLOUT;
165 prefix_ void senf::Scheduler::process()
168 while (! terminate_) {
170 MicroTime timeNow = now();
171 while ( ! timerQueue_.empty() && timerQueue_.top().timeout <= timeNow ) {
172 timerQueue_.top().cb();
177 int timeout = timerQueue_.empty() ? -1 : int((timerQueue_.top().timeout - timeNow)/1000);
179 struct epoll_event ev;
180 int events = epoll_wait(epollFd_, &ev, 1, timeout);
182 // Hmm ... man epoll says, it will NOT return with EINTR. I hope, this is true :-)
183 throw SystemException(errno);
185 // Timeout .. the handler will be run when going back to the loop top
188 FdTable::iterator i = fdTable_.find(ev.data.fd);
189 BOOST_ASSERT (i != fdTable_.end() );
190 // \todo Make this more efficient. Instead of copying the event-spec it should be
191 // revalidated by monitoring add/remove calls
192 EventSpec spec (i->second);
194 unsigned extraFlags (0);
195 if (ev.events & EPOLLHUP) extraFlags |= EV_HUP;
196 if (ev.events & EPOLLERR) extraFlags |= EV_ERR;
198 if (ev.events & EPOLLIN) {
199 BOOST_ASSERT(spec.cb_read);
200 spec.cb_read(EventId(EV_READ | extraFlags));
202 else if (ev.events & EPOLLPRI) {
203 BOOST_ASSERT(spec.cb_prio);
204 spec.cb_prio(EventId(EV_PRIO | extraFlags));
206 else if (ev.events & EPOLLOUT) {
207 BOOST_ASSERT(spec.cb_write);
208 spec.cb_write(EventId(EV_WRITE | extraFlags));
211 // This branch is only taken, if HUP or ERR is signaled but none of IN/OUT/PRI.
212 // In this case we will signal all registered callbacks. The callbacks must be
213 // prepared to be called multiple times if they are registered to more than
216 spec.cb_write(EventId(extraFlags));
218 spec.cb_prio(EventId(extraFlags));
220 spec.cb_read(EventId(extraFlags));
225 ///////////////////////////////cc.e////////////////////////////////////////
232 // c-file-style: "senf"
233 // indent-tabs-mode: nil
234 // ispell-local-dictionary: "american"
235 // compile-command: "scons -u test"
236 // comment-column: 40