libratbox/src/epoll.c

   1 /*
   2  *  ircd-ratbox: A slightly useful ircd.
   3  *  epoll.c: Linux epoll compatible network routines.
   4  *
   5  *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
   6  *  Copyright (C) 1996-2002 Hybrid Development Team
   7  *  Copyright (C) 2001 Adrian Chadd <adrian@creative.net.au>
   8  *  Copyright (C) 2002-2005 ircd-ratbox development team
   9  *  Copyright (C) 2002 Aaron Sethman <androsyn@ratbox.org>
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License as published by
  13  *  the Free Software Foundation; either version 2 of the License, or
  14  *  (at your option) any later version.
  15  *
  16  *  This program is distributed in the hope that it will be useful,
  17  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  *  GNU General Public License for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License
  22  *  along with this program; if not, write to the Free Software
  23  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
  24  *  USA
  25  *
  26  *  $Id: epoll.c 26092 2008-09-19 15:13:52Z androsyn $
  27  */
  28 #define _GNU_SOURCE 1
  29
  30 #include <libratbox_config.h>
  31 #include <ratbox_lib.h>
  32 #include <commio-int.h>
  33 #include <event-int.h>
  34 #if defined(HAVE_EPOLL_CTL) && (HAVE_SYS_EPOLL_H)
  35 #define USING_EPOLL
  36 #include <fcntl.h>
  37 #include <sys/epoll.h>
  38
  39 #if defined(HAVE_SIGNALFD) && (HAVE_SYS_SIGNALFD_H) && (USE_TIMER_CREATE) && (HAVE_SYS_UIO_H)
  40 #include <signal.h>
  41 #include <sys/signalfd.h>
  42 #include <sys/uio.h>
  43 #define EPOLL_SCHED_EVENT 1
  44 #endif
  45
  46 #if defined(USE_TIMERFD_CREATE)
  47 #include <sys/timerfd.h>
  48 #endif
  49
  50 #define RTSIGNAL SIGRTMIN
  51 struct epoll_info
  52 {
  53         int ep;
  54         struct epoll_event *pfd;
  55         int pfd_size;
  56 };
  57
  58 static struct epoll_info *ep_info;
  59 static int can_do_event;
  60 static int can_do_timerfd;
  61
  62 /*
  63  * rb_init_netio
  64  *
  65  * This is a needed exported function which will be called to initialise
  66  * the network loop code.
  67  */
  68 int
  69 rb_init_netio_epoll(void)
  70 {
  71         can_do_event = 0;       /* shut up gcc */
  72         ep_info = rb_malloc(sizeof(struct epoll_info));
  73         ep_info->pfd_size = getdtablesize();
  74         ep_info->ep = epoll_create(ep_info->pfd_size);
  75         if(ep_info->ep < 0)
  76         {
  77                 return -1;
  78         }
  79         rb_open(ep_info->ep, RB_FD_UNKNOWN, "epoll file descriptor");
  80         ep_info->pfd = rb_malloc(sizeof(struct epoll_event) * ep_info->pfd_size);
  81
  82         return 0;
  83 }
  84
  85 int
  86 rb_setup_fd_epoll(rb_fde_t *F)
  87 {
  88         return 0;
  89 }
  90
  91
  92 /*
  93  * rb_setselect
  94  *
  95  * This is a needed exported function which will be called to register
  96  * and deregister interest in a pending IO state for a given FD.
  97  */
  98 void
  99 rb_setselect_epoll(rb_fde_t *F, unsigned int type, PF * handler, void *client_data)
 100 {
 101         struct epoll_event ep_event;
 102         int old_flags = F->pflags;
 103         int op = -1;
 104
 105         lrb_assert(IsFDOpen(F));
 106
 107         /* Update the list, even though we're not using it .. */
 108         if(type & RB_SELECT_READ)
 109         {
 110                 if(handler != NULL)
 111                         F->pflags |= EPOLLIN;
 112                 else
 113                         F->pflags &= ~EPOLLIN;
 114                 F->read_handler = handler;
 115                 F->read_data = client_data;
 116         }
 117
 118         if(type & RB_SELECT_WRITE)
 119         {
 120                 if(handler != NULL)
 121                         F->pflags |= EPOLLOUT;
 122                 else
 123                         F->pflags &= ~EPOLLOUT;
 124                 F->write_handler = handler;
 125                 F->write_data = client_data;
 126         }
 127
 128         if(old_flags == 0 && F->pflags == 0)
 129                 return;
 130         else if(F->pflags <= 0)
 131                 op = EPOLL_CTL_DEL;
 132         else if(old_flags == 0 && F->pflags > 0)
 133                 op = EPOLL_CTL_ADD;
 134         else if(F->pflags != old_flags)
 135                 op = EPOLL_CTL_MOD;
 136
 137         if(op == -1)
 138                 return;
 139
 140         ep_event.events = F->pflags;
 141         ep_event.data.ptr = F;
 142
 143         if(op == EPOLL_CTL_ADD || op == EPOLL_CTL_MOD)
 144                 ep_event.events |= EPOLLET;
 145
 146         if(epoll_ctl(ep_info->ep, op, F->fd, &ep_event) != 0)
 147         {
 148                 rb_lib_log("rb_setselect_epoll(): epoll_ctl failed: %s", strerror(errno));
 149                 abort();
 150         }
 151
 152
 153 }
 154
 155 /*
 156  * rb_select
 157  *
 158  * Called to do the new-style IO, courtesy of squid (like most of this
 159  * new IO code). This routine handles the stuff we've hidden in
 160  * rb_setselect and fd_table[] and calls callbacks for IO ready
 161  * events.
 162  */
 163
 164 int
 165 rb_select_epoll(long delay)
 166 {
 167         int num, i, flags, old_flags, op;
 168         struct epoll_event ep_event;
 169         int o_errno;
 170         void *data;
 171
 172         num = epoll_wait(ep_info->ep, ep_info->pfd, ep_info->pfd_size, delay);
 173
 174         /* save errno as rb_set_time() will likely clobber it */
 175         o_errno = errno;
 176         rb_set_time();
 177         errno = o_errno;
 178
 179         if(num < 0 && !rb_ignore_errno(o_errno))
 180                 return RB_ERROR;
 181
 182         if(num <= 0)
 183                 return RB_OK;
 184
 185         for(i = 0; i < num; i++)
 186         {
 187                 PF *hdl;
 188                 rb_fde_t *F = ep_info->pfd[i].data.ptr;
 189                 old_flags = F->pflags;
 190                 if(ep_info->pfd[i].events & (EPOLLIN | EPOLLHUP | EPOLLERR))
 191                 {
 192                         hdl = F->read_handler;
 193                         data = F->read_data;
 194                         F->read_handler = NULL;
 195                         F->read_data = NULL;
 196                         if(hdl)
 197                         {
 198                                 hdl(F, data);
 199                         }
 200                 }
 201
 202                 if(!IsFDOpen(F))
 203                         continue;
 204                 if(ep_info->pfd[i].events & (EPOLLOUT | EPOLLHUP | EPOLLERR))
 205                 {
 206                         hdl = F->write_handler;
 207                         data = F->write_data;
 208                         F->write_handler = NULL;
 209                         F->write_data = NULL;
 210
 211                         if(hdl)
 212                         {
 213                                 hdl(F, data);
 214                         }
 215                 }
 216
 217                 if(!IsFDOpen(F))
 218                         continue;
 219
 220                 flags = 0;
 221
 222                 if(F->read_handler != NULL)
 223                         flags |= EPOLLIN;
 224                 if(F->write_handler != NULL)
 225                         flags |= EPOLLOUT;
 226
 227                 if(old_flags != flags)
 228                 {
 229                         if(flags == 0)
 230                                 op = EPOLL_CTL_DEL;
 231                         else
 232                                 op = EPOLL_CTL_MOD;
 233                         F->pflags = ep_event.events = flags;
 234                         ep_event.data.ptr = F;
 235                         if(op == EPOLL_CTL_MOD || op == EPOLL_CTL_ADD)
 236                                 ep_event.events |= EPOLLET;
 237
 238                         if(epoll_ctl(ep_info->ep, op, F->fd, &ep_event) != 0)
 239                         {
 240                                 rb_lib_log("rb_select_epoll(): epoll_ctl failed: %s",
 241                                            strerror(errno));
 242                         }
 243                 }
 244
 245         }
 246         return RB_OK;
 247 }
 248
 249 #ifdef EPOLL_SCHED_EVENT
 250 int
 251 rb_epoll_supports_event(void)
 252 {
 253         /* try to detect at runtime if everything we need actually works */
 254         timer_t timer;
 255         struct sigevent ev;
 256         int fd;
 257         sigset_t set;
 258
 259         if(can_do_event == 1)
 260                 return 1;
 261         if(can_do_event == -1)
 262                 return 0;
 263
 264 #ifdef USE_TIMERFD_CREATE
 265         if((fd = timerfd_create(CLOCK_REALTIME, 0)) >= 0)
 266         {
 267                 close(fd);
 268                 can_do_event = 1;
 269                 can_do_timerfd = 1;
 270                 return 0;
 271         }
 272 #endif
 273
 274         ev.sigev_signo = SIGVTALRM;
 275         ev.sigev_notify = SIGEV_SIGNAL;
 276         if(timer_create(CLOCK_REALTIME, &ev, &timer) != 0)
 277         {
 278                 can_do_event = -1;
 279                 return 0;
 280         }
 281         timer_delete(timer);
 282         sigemptyset(&set);
 283         fd = signalfd(-1, &set, 0);
 284         if(fd < 0)
 285         {
 286                 can_do_event = -1;
 287                 return 0;
 288         }
 289         close(fd);
 290         can_do_event = 1;
 291         return 1;
 292 }
 293
 294
 295 /* bleh..work around a glibc header bug on 32bit systems */
 296 struct our_signalfd_siginfo
 297 {
 298         uint32_t signo;
 299         int32_t err;
 300         int32_t code;
 301         uint32_t pid;
 302         uint32_t uid;
 303         int32_t fd;
 304         uint32_t tid;
 305         uint32_t band;
 306         uint32_t overrun;
 307         uint32_t trapno;
 308         int32_t status;
 309         int32_t svint;
 310         uint64_t svptr;
 311         uint64_t utime;
 312         uint64_t stime;
 313         uint64_t addr;
 314         uint8_t pad[48];
 315 };
 316
 317
 318 #define SIGFDIOV_COUNT 16
 319 static void
 320 signalfd_handler(rb_fde_t *F, void *data)
 321 {
 322         static struct our_signalfd_siginfo fdsig[SIGFDIOV_COUNT];
 323         static struct iovec iov[SIGFDIOV_COUNT];
 324         struct ev_entry *ev;
 325         int ret, x;
 326
 327         for(x = 0; x < SIGFDIOV_COUNT; x++)
 328         {
 329                 iov[x].iov_base = &fdsig[x];
 330                 iov[x].iov_len = sizeof(struct our_signalfd_siginfo);
 331         }
 332
 333         while(1)
 334         {
 335                 ret = readv(rb_get_fd(F), iov, SIGFDIOV_COUNT);
 336                 if(ret == 0 || (ret < 0 && !rb_ignore_errno(errno)))
 337                 {
 338                         rb_close(F);
 339                         rb_epoll_init_event();
 340                         return;
 341                 }
 342
 343                 if(ret < 0)
 344                 {
 345                         rb_setselect(F, RB_SELECT_READ, signalfd_handler, NULL);
 346                         return;
 347                 }
 348                 for(x = 0; x < ret / (int)sizeof(struct our_signalfd_siginfo); x++)
 349                 {
 350                         ev = (struct ev_entry *)((uintptr_t)fdsig[x].svptr);
 351                         if(ev == NULL)
 352                                 continue;
 353                         rb_run_event(ev);
 354                 }
 355         }
 356 }
 357
 358 void
 359 rb_epoll_init_event(void)
 360 {
 361
 362         sigset_t ss;
 363         rb_fde_t *F;
 364         int sfd;
 365         rb_epoll_supports_event();
 366         if(!can_do_timerfd)
 367         {
 368                 sigemptyset(&ss);
 369                 sigaddset(&ss, RTSIGNAL);
 370                 sigprocmask(SIG_BLOCK, &ss, 0);
 371                 sigemptyset(&ss);
 372                 sigaddset(&ss, RTSIGNAL);
 373                 sfd = signalfd(-1, &ss, 0);
 374                 if(sfd == -1)
 375                 {
 376                         can_do_event = -1;
 377                         return;
 378                 }
 379                 F = rb_open(sfd, RB_FD_UNKNOWN, "signalfd");
 380                 rb_set_nb(F);
 381                 signalfd_handler(F, NULL);
 382         }
 383 }
 384
 385 static int
 386 rb_epoll_sched_event_signalfd(struct ev_entry *event, int when)
 387 {
 388         timer_t *id;
 389         struct sigevent ev;
 390         struct itimerspec ts;
 391
 392         memset(&ev, 0, sizeof(&ev));
 393         event->comm_ptr = rb_malloc(sizeof(timer_t));
 394         id = event->comm_ptr;
 395         ev.sigev_notify = SIGEV_SIGNAL;
 396         ev.sigev_signo = RTSIGNAL;
 397         ev.sigev_value.sival_ptr = event;
 398
 399         if(timer_create(CLOCK_REALTIME, &ev, id) < 0)
 400         {
 401                 rb_lib_log("timer_create: %s\n", strerror(errno));
 402                 return 0;
 403         }
 404         memset(&ts, 0, sizeof(ts));
 405         ts.it_value.tv_sec = when;
 406         ts.it_value.tv_nsec = 0;
 407         if(event->frequency != 0)
 408                 ts.it_interval = ts.it_value;
 409
 410         if(timer_settime(*id, 0, &ts, NULL) < 0)
 411         {
 412                 rb_lib_log("timer_settime: %s\n", strerror(errno));
 413                 return 0;
 414         }
 415         return 1;
 416 }
 417
 418 #ifdef USE_TIMERFD_CREATE
 419 static void
 420 rb_read_timerfd(rb_fde_t *F, void *data)
 421 {
 422         struct ev_entry *event = (struct ev_entry *)data;
 423         int retlen;
 424         uint64_t count;
 425
 426         if(event == NULL)
 427         {
 428                 rb_close(F);
 429                 return;
 430         }
 431
 432         retlen = rb_read(F, &count, sizeof(count));
 433         if(retlen == 0 || (retlen < 0 && !rb_ignore_errno(errno)))
 434         {
 435                 rb_close(F);
 436                 rb_lib_log("rb_read_timerfd: timerfd[%s] closed on error: %s", event->name,
 437                            strerror(errno));
 438                 return;
 439         }
 440         rb_setselect(F, RB_SELECT_READ, rb_read_timerfd, event);
 441         rb_run_event(event);
 442 }
 443
 444
 445 static int
 446 rb_epoll_sched_event_timerfd(struct ev_entry *event, int when)
 447 {
 448         struct itimerspec ts;
 449         static char buf[FD_DESC_SZ + 8];
 450         int fd;
 451         rb_fde_t *F;
 452
 453         if((fd = timerfd_create(CLOCK_REALTIME, 0)) < 0)
 454         {
 455                 rb_lib_log("timerfd_create: %s\n", strerror(errno));
 456                 return 0;
 457         }
 458
 459         memset(&ts, 0, sizeof(ts));
 460         ts.it_value.tv_sec = when;
 461         ts.it_value.tv_nsec = 0;
 462         if(event->frequency != 0)
 463                 ts.it_interval = ts.it_value;
 464
 465         if(timerfd_settime(fd, 0, &ts, NULL) < 0)
 466         {
 467                 rb_lib_log("timerfd_settime: %s\n", strerror(errno));
 468                 close(fd);
 469                 return 0;
 470         }
 471         rb_snprintf(buf, sizeof(buf), "timerfd: %s", event->name);
 472         F = rb_open(fd, RB_FD_UNKNOWN, buf);
 473         rb_set_nb(F);
 474         event->comm_ptr = F;
 475         rb_setselect(F, RB_SELECT_READ, rb_read_timerfd, event);
 476         return 1;
 477 }
 478 #endif
 479
 480
 481
 482 int
 483 rb_epoll_sched_event(struct ev_entry *event, int when)
 484 {
 485 #ifdef USE_TIMERFD_CREATE
 486         if(can_do_timerfd)
 487         {
 488                 return rb_epoll_sched_event_timerfd(event, when);
 489         }
 490 #endif
 491         return rb_epoll_sched_event_signalfd(event, when);
 492 }
 493
 494 void
 495 rb_epoll_unsched_event(struct ev_entry *event)
 496 {
 497 #ifdef USE_TIMERFD_CREATE
 498         if(can_do_timerfd)
 499         {
 500                 rb_close((rb_fde_t *)event->comm_ptr);
 501                 event->comm_ptr = NULL;
 502                 return;
 503         }
 504 #endif
 505         timer_delete(*((timer_t *) event->comm_ptr));
 506         rb_free(event->comm_ptr);
 507         event->comm_ptr = NULL;
 508 }
 509 #endif /* EPOLL_SCHED_EVENT */
 510
 511 #else /* epoll not supported here */
 512 int
 513 rb_init_netio_epoll(void)
 514 {
 515         return ENOSYS;
 516 }
 517
 518 void
 519 rb_setselect_epoll(rb_fde_t *F, unsigned int type, PF * handler, void *client_data)
 520 {
 521         errno = ENOSYS;
 522         return;
 523 }
 524
 525 int
 526 rb_select_epoll(long delay)
 527 {
 528         errno = ENOSYS;
 529         return -1;
 530 }
 531
 532 int
 533 rb_setup_fd_epoll(rb_fde_t *F)
 534 {
 535         errno = ENOSYS;
 536         return -1;
 537 }
 538
 539
 540 #endif
 541
 542 #if !defined(USING_EPOLL) || !defined(EPOLL_SCHED_EVENT)
 543 void
 544 rb_epoll_init_event(void)
 545 {
 546         return;
 547 }
 548
 549 int
 550 rb_epoll_sched_event(struct ev_entry *event, int when)
 551 {
 552         errno = ENOSYS;
 553         return -1;
 554 }
 555
 556 void
 557 rb_epoll_unsched_event(struct ev_entry *event)
 558 {
 559         return;
 560 }
 561
 562 int
 563 rb_epoll_supports_event(void)
 564 {
 565         errno = ENOSYS;
 566         return 0;
 567 }
 568 #endif /* !USING_EPOLL || !EPOLL_SCHED_EVENT */