uloop.c

   1 /*
   2  * uloop - event loop implementation
   3  *
   4  * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #include <sys/time.h>
  19 #include <sys/types.h>
  20
  21 #include <unistd.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <errno.h>
  25 #include <poll.h>
  26 #include <string.h>
  27 #include <fcntl.h>
  28 #include <stdbool.h>
  29
  30 #include "uloop.h"
  31 #include "utils.h"
  32
  33 #ifdef USE_KQUEUE
  34 #include <sys/event.h>
  35 #endif
  36 #ifdef USE_EPOLL
  37 #include <sys/epoll.h>
  38 #endif
  39 #include <sys/wait.h>
  40
  41 struct uloop_fd_event {
  42         struct uloop_fd *fd;
  43         unsigned int events;
  44 };
  45
  46 #define ULOOP_MAX_EVENTS 10
  47
  48 static struct list_head timeouts = LIST_HEAD_INIT(timeouts);
  49 static struct list_head processes = LIST_HEAD_INIT(processes);
  50
  51 static int poll_fd = -1;
  52 bool uloop_cancelled = false;
  53 bool uloop_handle_sigchld = true;
  54 static bool do_sigchld = false;
  55
  56 static struct uloop_fd_event cur_fds[ULOOP_MAX_EVENTS];
  57 static int cur_fd, cur_nfds;
  58
  59 #ifdef USE_KQUEUE
  60
  61 int uloop_init(void)
  62 {
  63         struct timespec timeout = { 0, 0 };
  64         struct kevent ev = {};
  65
  66         if (poll_fd >= 0)
  67                 return 0;
  68
  69         poll_fd = kqueue();
  70         if (poll_fd < 0)
  71                 return -1;
  72
  73         EV_SET(&ev, SIGCHLD, EVFILT_SIGNAL, EV_ADD, 0, 0, 0);
  74         kevent(poll_fd, &ev, 1, NULL, 0, &timeout);
  75
  76         return 0;
  77 }
  78
  79
  80 static uint16_t get_flags(unsigned int flags, unsigned int mask)
  81 {
  82         uint16_t kflags = 0;
  83
  84         if (!(flags & mask))
  85                 return EV_DELETE;
  86
  87         kflags = EV_ADD;
  88         if (flags & ULOOP_EDGE_TRIGGER)
  89                 kflags |= EV_CLEAR;
  90
  91         return kflags;
  92 }
  93
  94 static struct kevent events[ULOOP_MAX_EVENTS];
  95
  96 static int register_kevent(struct uloop_fd *fd, unsigned int flags)
  97 {
  98         struct timespec timeout = { 0, 0 };
  99         struct kevent ev[2];
 100         int nev = 0;
 101         unsigned int fl = 0;
 102         unsigned int changed;
 103         uint16_t kflags;
 104
 105         if (flags & ULOOP_EDGE_DEFER)
 106                 flags &= ~ULOOP_EDGE_TRIGGER;
 107
 108         changed = flags ^ fd->flags;
 109         if (changed & ULOOP_EDGE_TRIGGER)
 110                 changed |= flags;
 111
 112         if (changed & ULOOP_READ) {
 113                 kflags = get_flags(flags, ULOOP_READ);
 114                 EV_SET(&ev[nev++], fd->fd, EVFILT_READ, kflags, 0, 0, fd);
 115         }
 116
 117         if (changed & ULOOP_WRITE) {
 118                 kflags = get_flags(flags, ULOOP_WRITE);
 119                 EV_SET(&ev[nev++], fd->fd, EVFILT_WRITE, kflags, 0, 0, fd);
 120         }
 121
 122         if (!flags)
 123                 fl |= EV_DELETE;
 124
 125         fd->flags = flags;
 126         if (kevent(poll_fd, ev, nev, NULL, fl, &timeout) == -1)
 127                 return -1;
 128
 129         return 0;
 130 }
 131
 132 static int register_poll(struct uloop_fd *fd, unsigned int flags)
 133 {
 134         if (flags & ULOOP_EDGE_TRIGGER)
 135                 flags |= ULOOP_EDGE_DEFER;
 136         else
 137                 flags &= ~ULOOP_EDGE_DEFER;
 138
 139         return register_kevent(fd, flags);
 140 }
 141
 142 static int __uloop_fd_delete(struct uloop_fd *fd)
 143 {
 144         return register_poll(fd, 0);
 145 }
 146
 147 static int uloop_fetch_events(int timeout)
 148 {
 149         struct timespec ts;
 150         int nfds, n;
 151
 152         if (timeout >= 0) {
 153                 ts.tv_sec = timeout / 1000;
 154                 ts.tv_nsec = (timeout % 1000) * 1000000;
 155         }
 156
 157         nfds = kevent(poll_fd, NULL, 0, events, ARRAY_SIZE(events), timeout >= 0 ? &ts : NULL);
 158         for (n = 0; n < nfds; n++) {
 159                 struct uloop_fd_event *cur = &cur_fds[n];
 160                 struct uloop_fd *u = events[n].udata;
 161                 unsigned int ev = 0;
 162
 163                 cur->fd = u;
 164                 if (!u)
 165                         continue;
 166
 167                 if (events[n].flags & EV_ERROR) {
 168                         u->error = true;
 169                         uloop_fd_delete(u);
 170                 }
 171
 172                 if(events[n].filter == EVFILT_READ)
 173                         ev |= ULOOP_READ;
 174                 else if (events[n].filter == EVFILT_WRITE)
 175                         ev |= ULOOP_WRITE;
 176
 177                 if (events[n].flags & EV_EOF)
 178                         u->eof = true;
 179                 else if (!ev)
 180                         cur->fd = NULL;
 181
 182                 cur->events = ev;
 183                 if (u->flags & ULOOP_EDGE_DEFER) {
 184                         u->flags &= ~ULOOP_EDGE_DEFER;
 185                         u->flags |= ULOOP_EDGE_TRIGGER;
 186                         register_kevent(u, u->flags);
 187                 }
 188         }
 189         return nfds;
 190 }
 191
 192 #endif
 193
 194 #ifdef USE_EPOLL
 195
 196 /**
 197  * FIXME: uClibc < 0.9.30.3 does not define EPOLLRDHUP for Linux >= 2.6.17
 198  */
 199 #ifndef EPOLLRDHUP
 200 #define EPOLLRDHUP 0x2000
 201 #endif
 202
 203 int uloop_init(void)
 204 {
 205         if (poll_fd >= 0)
 206                 return 0;
 207
 208         poll_fd = epoll_create(32);
 209         if (poll_fd < 0)
 210                 return -1;
 211
 212         fcntl(poll_fd, F_SETFD, fcntl(poll_fd, F_GETFD) | FD_CLOEXEC);
 213         return 0;
 214 }
 215
 216 static int register_poll(struct uloop_fd *fd, unsigned int flags)
 217 {
 218         struct epoll_event ev;
 219         int op = fd->registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
 220
 221         memset(&ev, 0, sizeof(struct epoll_event));
 222
 223         if (flags & ULOOP_READ)
 224                 ev.events |= EPOLLIN | EPOLLRDHUP;
 225
 226         if (flags & ULOOP_WRITE)
 227                 ev.events |= EPOLLOUT;
 228
 229         if (flags & ULOOP_EDGE_TRIGGER)
 230                 ev.events |= EPOLLET;
 231
 232         ev.data.fd = fd->fd;
 233         ev.data.ptr = fd;
 234         fd->flags = flags;
 235
 236         return epoll_ctl(poll_fd, op, fd->fd, &ev);
 237 }
 238
 239 static struct epoll_event events[ULOOP_MAX_EVENTS];
 240
 241 static int __uloop_fd_delete(struct uloop_fd *sock)
 242 {
 243         sock->flags = 0;
 244         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 245 }
 246
 247 static int uloop_fetch_events(int timeout)
 248 {
 249         int n, nfds;
 250
 251         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
 252         for (n = 0; n < nfds; ++n) {
 253                 struct uloop_fd_event *cur = &cur_fds[n];
 254                 struct uloop_fd *u = events[n].data.ptr;
 255                 unsigned int ev = 0;
 256
 257                 cur->fd = u;
 258                 if (!u)
 259                         continue;
 260
 261                 if (events[n].events & (EPOLLERR|EPOLLHUP)) {
 262                         u->error = true;
 263                         uloop_fd_delete(u);
 264                 }
 265
 266                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP))) {
 267                         cur->fd = NULL;
 268                         continue;
 269                 }
 270
 271                 if(events[n].events & EPOLLRDHUP)
 272                         u->eof = true;
 273
 274                 if(events[n].events & EPOLLIN)
 275                         ev |= ULOOP_READ;
 276
 277                 if(events[n].events & EPOLLOUT)
 278                         ev |= ULOOP_WRITE;
 279
 280                 cur->events = ev;
 281         }
 282
 283         return nfds;
 284 }
 285
 286 #endif
 287
 288 static void uloop_run_events(int timeout)
 289 {
 290         struct uloop_fd_event *cur;
 291         struct uloop_fd *fd;
 292
 293         if (!cur_nfds) {
 294                 cur_fd = 0;
 295                 cur_nfds = uloop_fetch_events(timeout);
 296                 if (cur_nfds < 0)
 297                         cur_nfds = 0;
 298         }
 299
 300         while (cur_nfds > 0) {
 301                 cur = &cur_fds[cur_fd++];
 302                 cur_nfds--;
 303
 304                 fd = cur->fd;
 305                 if (!fd)
 306                         continue;
 307
 308                 if (!fd->cb)
 309                         continue;
 310
 311                 fd->cb(fd, cur->events);
 312                 return;
 313         }
 314 }
 315
 316 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
 317 {
 318         unsigned int fl;
 319         int ret;
 320
 321         if (!(flags & (ULOOP_READ | ULOOP_WRITE)))
 322                 return uloop_fd_delete(sock);
 323
 324         if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
 325                 fl = fcntl(sock->fd, F_GETFL, 0);
 326                 fl |= O_NONBLOCK;
 327                 fcntl(sock->fd, F_SETFL, fl);
 328         }
 329
 330         ret = register_poll(sock, flags);
 331         if (ret < 0)
 332                 goto out;
 333
 334         sock->registered = true;
 335         sock->eof = false;
 336
 337 out:
 338         return ret;
 339 }
 340
 341 int uloop_fd_delete(struct uloop_fd *fd)
 342 {
 343         int i;
 344
 345         if (!fd->registered)
 346                 return 0;
 347
 348         for (i = 0; i < cur_nfds; i++) {
 349                 if (cur_fds[cur_fd + i].fd != fd)
 350                         continue;
 351
 352                 cur_fds[cur_fd + i].fd = NULL;
 353         }
 354         fd->registered = false;
 355         return __uloop_fd_delete(fd);
 356 }
 357
 358 static int tv_diff(struct timeval *t1, struct timeval *t2)
 359 {
 360         return
 361                 (t1->tv_sec - t2->tv_sec) * 1000 +
 362                 (t1->tv_usec - t2->tv_usec) / 1000;
 363 }
 364
 365 int uloop_timeout_add(struct uloop_timeout *timeout)
 366 {
 367         struct uloop_timeout *tmp;
 368         struct list_head *h = &timeouts;
 369
 370         if (timeout->pending)
 371                 return -1;
 372
 373         list_for_each_entry(tmp, &timeouts, list) {
 374                 if (tv_diff(&tmp->time, &timeout->time) > 0) {
 375                         h = &tmp->list;
 376                         break;
 377                 }
 378         }
 379
 380         list_add_tail(&timeout->list, h);
 381         timeout->pending = true;
 382
 383         return 0;
 384 }
 385
 386 static void uloop_gettime(struct timeval *tv)
 387 {
 388         struct timespec ts;
 389
 390         clock_gettime(CLOCK_MONOTONIC, &ts);
 391         tv->tv_sec = ts.tv_sec;
 392         tv->tv_usec = ts.tv_nsec / 1000;
 393 }
 394
 395 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 396 {
 397         struct timeval *time = &timeout->time;
 398
 399         if (timeout->pending)
 400                 uloop_timeout_cancel(timeout);
 401
 402         uloop_gettime(&timeout->time);
 403
 404         time->tv_sec += msecs / 1000;
 405         time->tv_usec += (msecs % 1000) * 1000;
 406
 407         if (time->tv_usec > 1000000) {
 408                 time->tv_sec++;
 409                 time->tv_usec %= 1000000;
 410         }
 411
 412         return uloop_timeout_add(timeout);
 413 }
 414
 415 int uloop_timeout_cancel(struct uloop_timeout *timeout)
 416 {
 417         if (!timeout->pending)
 418                 return -1;
 419
 420         list_del(&timeout->list);
 421         timeout->pending = false;
 422
 423         return 0;
 424 }
 425
 426 int uloop_timeout_remaining(struct uloop_timeout *timeout)
 427 {
 428         struct timeval now;
 429
 430         if (!timeout->pending)
 431                 return -1;
 432
 433         uloop_gettime(&now);
 434
 435         return tv_diff(&timeout->time, &now);
 436 }
 437
 438 int uloop_process_add(struct uloop_process *p)
 439 {
 440         struct uloop_process *tmp;
 441         struct list_head *h = &processes;
 442
 443         if (p->pending)
 444                 return -1;
 445
 446         list_for_each_entry(tmp, &processes, list) {
 447                 if (tmp->pid > p->pid) {
 448                         h = &tmp->list;
 449                         break;
 450                 }
 451         }
 452
 453         list_add_tail(&p->list, h);
 454         p->pending = true;
 455
 456         return 0;
 457 }
 458
 459 int uloop_process_delete(struct uloop_process *p)
 460 {
 461         if (!p->pending)
 462                 return -1;
 463
 464         list_del(&p->list);
 465         p->pending = false;
 466
 467         return 0;
 468 }
 469
 470 static void uloop_handle_processes(void)
 471 {
 472         struct uloop_process *p, *tmp;
 473         pid_t pid;
 474         int ret;
 475
 476         do_sigchld = false;
 477
 478         while (1) {
 479                 pid = waitpid(-1, &ret, WNOHANG);
 480                 if (pid <= 0)
 481                         return;
 482
 483                 list_for_each_entry_safe(p, tmp, &processes, list) {
 484                         if (p->pid < pid)
 485                                 continue;
 486
 487                         if (p->pid > pid)
 488                                 break;
 489
 490                         uloop_process_delete(p);
 491                         p->cb(p, ret);
 492                 }
 493         }
 494
 495 }
 496
 497 static void uloop_handle_sigint(int signo)
 498 {
 499         uloop_cancelled = true;
 500 }
 501
 502 static void uloop_sigchld(int signo)
 503 {
 504         do_sigchld = true;
 505 }
 506
 507 static void uloop_setup_signals(void)
 508 {
 509         struct sigaction s;
 510
 511         memset(&s, 0, sizeof(struct sigaction));
 512         s.sa_handler = uloop_handle_sigint;
 513         s.sa_flags = 0;
 514         sigaction(SIGINT, &s, NULL);
 515
 516         if (uloop_handle_sigchld) {
 517                 s.sa_handler = uloop_sigchld;
 518                 sigaction(SIGCHLD, &s, NULL);
 519         }
 520 }
 521
 522 static int uloop_get_next_timeout(struct timeval *tv)
 523 {
 524         struct uloop_timeout *timeout;
 525         int diff;
 526
 527         if (list_empty(&timeouts))
 528                 return -1;
 529
 530         timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
 531         diff = tv_diff(&timeout->time, tv);
 532         if (diff < 0)
 533                 return 0;
 534
 535         return diff;
 536 }
 537
 538 static void uloop_process_timeouts(struct timeval *tv)
 539 {
 540         struct uloop_timeout *t;
 541
 542         while (!list_empty(&timeouts)) {
 543                 t = list_first_entry(&timeouts, struct uloop_timeout, list);
 544
 545                 if (tv_diff(&t->time, tv) > 0)
 546                         break;
 547
 548                 uloop_timeout_cancel(t);
 549                 if (t->cb)
 550                         t->cb(t);
 551         }
 552 }
 553
 554 static void uloop_clear_timeouts(void)
 555 {
 556         struct uloop_timeout *t, *tmp;
 557
 558         list_for_each_entry_safe(t, tmp, &timeouts, list)
 559                 uloop_timeout_cancel(t);
 560 }
 561
 562 static void uloop_clear_processes(void)
 563 {
 564         struct uloop_process *p, *tmp;
 565
 566         list_for_each_entry_safe(p, tmp, &processes, list)
 567                 uloop_process_delete(p);
 568 }
 569
 570 void uloop_run(void)
 571 {
 572         struct timeval tv;
 573
 574         uloop_setup_signals();
 575         while(!uloop_cancelled)
 576         {
 577                 uloop_gettime(&tv);
 578                 uloop_process_timeouts(&tv);
 579                 if (uloop_cancelled)
 580                         break;
 581
 582                 if (do_sigchld)
 583                         uloop_handle_processes();
 584                 uloop_run_events(uloop_get_next_timeout(&tv));
 585         }
 586 }
 587
 588 void uloop_done(void)
 589 {
 590         if (poll_fd < 0)
 591                 return;
 592
 593         close(poll_fd);
 594         poll_fd = -1;
 595
 596         uloop_clear_timeouts();
 597         uloop_clear_processes();
 598 }