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                 if (u->flags & ULOOP_EDGE_DEFER) {
 183                         u->flags &= ~ULOOP_EDGE_DEFER;
 184                         u->flags |= ULOOP_EDGE_TRIGGER;
 185                         register_kevent(u, u->flags);
 186                 }
 187         }
 188         return nfds;
 189 }
 190
 191 #endif
 192
 193 #ifdef USE_EPOLL
 194
 195 /**
 196  * FIXME: uClibc < 0.9.30.3 does not define EPOLLRDHUP for Linux >= 2.6.17
 197  */
 198 #ifndef EPOLLRDHUP
 199 #define EPOLLRDHUP 0x2000
 200 #endif
 201
 202 int uloop_init(void)
 203 {
 204         if (poll_fd >= 0)
 205                 return 0;
 206
 207         poll_fd = epoll_create(32);
 208         if (poll_fd < 0)
 209                 return -1;
 210
 211         fcntl(poll_fd, F_SETFD, fcntl(poll_fd, F_GETFD) | FD_CLOEXEC);
 212         return 0;
 213 }
 214
 215 static int register_poll(struct uloop_fd *fd, unsigned int flags)
 216 {
 217         struct epoll_event ev;
 218         int op = fd->registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
 219
 220         memset(&ev, 0, sizeof(struct epoll_event));
 221
 222         if (flags & ULOOP_READ)
 223                 ev.events |= EPOLLIN | EPOLLRDHUP;
 224
 225         if (flags & ULOOP_WRITE)
 226                 ev.events |= EPOLLOUT;
 227
 228         if (flags & ULOOP_EDGE_TRIGGER)
 229                 ev.events |= EPOLLET;
 230
 231         ev.data.fd = fd->fd;
 232         ev.data.ptr = fd;
 233
 234         return epoll_ctl(poll_fd, op, fd->fd, &ev);
 235 }
 236
 237 static struct epoll_event events[ULOOP_MAX_EVENTS];
 238
 239 static int __uloop_fd_delete(struct uloop_fd *sock)
 240 {
 241         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 242 }
 243
 244 static int uloop_fetch_events(int timeout)
 245 {
 246         int n, nfds;
 247
 248         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
 249         for (n = 0; n < nfds; ++n) {
 250                 struct uloop_fd_event *cur = &cur_fds[n];
 251                 struct uloop_fd *u = events[n].data.ptr;
 252                 unsigned int ev = 0;
 253
 254                 cur->fd = u;
 255                 if (!u)
 256                         continue;
 257
 258                 if (events[n].events & (EPOLLERR|EPOLLHUP)) {
 259                         u->error = true;
 260                         uloop_fd_delete(u);
 261                 }
 262
 263                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP))) {
 264                         cur->fd = NULL;
 265                         continue;
 266                 }
 267
 268                 if(events[n].events & EPOLLRDHUP)
 269                         u->eof = true;
 270
 271                 if(events[n].events & EPOLLIN)
 272                         ev |= ULOOP_READ;
 273
 274                 if(events[n].events & EPOLLOUT)
 275                         ev |= ULOOP_WRITE;
 276
 277                 cur->events = ev;
 278         }
 279
 280         return nfds;
 281 }
 282
 283 #endif
 284
 285 static void uloop_run_events(int timeout)
 286 {
 287         struct uloop_fd_event *cur;
 288         struct uloop_fd *fd;
 289
 290         if (!cur_nfds) {
 291                 cur_fd = 0;
 292                 cur_nfds = uloop_fetch_events(timeout);
 293                 if (cur_nfds < 0)
 294                         cur_nfds = 0;
 295         }
 296
 297         while (cur_nfds > 0) {
 298                 cur = &cur_fds[cur_fd++];
 299                 cur_nfds--;
 300
 301                 fd = cur->fd;
 302                 if (!fd)
 303                         continue;
 304
 305                 if (!fd->cb)
 306                         continue;
 307
 308                 fd->cb(fd, cur->events);
 309                 return;
 310         }
 311 }
 312
 313 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
 314 {
 315         unsigned int fl;
 316         int ret;
 317
 318         if (!(flags & (ULOOP_READ | ULOOP_WRITE)))
 319                 return uloop_fd_delete(sock);
 320
 321         if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
 322                 fl = fcntl(sock->fd, F_GETFL, 0);
 323                 fl |= O_NONBLOCK;
 324                 fcntl(sock->fd, F_SETFL, fl);
 325         }
 326
 327         ret = register_poll(sock, flags);
 328         if (ret < 0)
 329                 goto out;
 330
 331         sock->registered = true;
 332         sock->eof = false;
 333
 334 out:
 335         return ret;
 336 }
 337
 338 int uloop_fd_delete(struct uloop_fd *fd)
 339 {
 340         int i;
 341
 342         if (!fd->registered)
 343                 return 0;
 344
 345         for (i = 0; i < cur_nfds; i++) {
 346                 if (cur_fds[cur_fd + i].fd != fd)
 347                         continue;
 348
 349                 cur_fds[cur_fd + i].fd = NULL;
 350         }
 351         fd->registered = false;
 352         return __uloop_fd_delete(fd);
 353 }
 354
 355 static int tv_diff(struct timeval *t1, struct timeval *t2)
 356 {
 357         return
 358                 (t1->tv_sec - t2->tv_sec) * 1000 +
 359                 (t1->tv_usec - t2->tv_usec) / 1000;
 360 }
 361
 362 int uloop_timeout_add(struct uloop_timeout *timeout)
 363 {
 364         struct uloop_timeout *tmp;
 365         struct list_head *h = &timeouts;
 366
 367         if (timeout->pending)
 368                 return -1;
 369
 370         list_for_each_entry(tmp, &timeouts, list) {
 371                 if (tv_diff(&tmp->time, &timeout->time) > 0) {
 372                         h = &tmp->list;
 373                         break;
 374                 }
 375         }
 376
 377         list_add_tail(&timeout->list, h);
 378         timeout->pending = true;
 379
 380         return 0;
 381 }
 382
 383 static void uloop_gettime(struct timeval *tv)
 384 {
 385         struct timespec ts;
 386
 387         clock_gettime(CLOCK_MONOTONIC, &ts);
 388         tv->tv_sec = ts.tv_sec;
 389         tv->tv_usec = ts.tv_nsec / 1000;
 390 }
 391
 392 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 393 {
 394         struct timeval *time = &timeout->time;
 395
 396         if (timeout->pending)
 397                 uloop_timeout_cancel(timeout);
 398
 399         uloop_gettime(&timeout->time);
 400
 401         time->tv_sec += msecs / 1000;
 402         time->tv_usec += (msecs % 1000) * 1000;
 403
 404         if (time->tv_usec > 1000000) {
 405                 time->tv_sec++;
 406                 time->tv_usec %= 1000000;
 407         }
 408
 409         return uloop_timeout_add(timeout);
 410 }
 411
 412 int uloop_timeout_cancel(struct uloop_timeout *timeout)
 413 {
 414         if (!timeout->pending)
 415                 return -1;
 416
 417         list_del(&timeout->list);
 418         timeout->pending = false;
 419
 420         return 0;
 421 }
 422
 423 int uloop_timeout_remaining(struct uloop_timeout *timeout)
 424 {
 425         struct timeval now;
 426
 427         if (!timeout->pending)
 428                 return -1;
 429
 430         uloop_gettime(&now);
 431
 432         return tv_diff(&timeout->time, &now);
 433 }
 434
 435 int uloop_process_add(struct uloop_process *p)
 436 {
 437         struct uloop_process *tmp;
 438         struct list_head *h = &processes;
 439
 440         if (p->pending)
 441                 return -1;
 442
 443         list_for_each_entry(tmp, &processes, list) {
 444                 if (tmp->pid > p->pid) {
 445                         h = &tmp->list;
 446                         break;
 447                 }
 448         }
 449
 450         list_add_tail(&p->list, h);
 451         p->pending = true;
 452
 453         return 0;
 454 }
 455
 456 int uloop_process_delete(struct uloop_process *p)
 457 {
 458         if (!p->pending)
 459                 return -1;
 460
 461         list_del(&p->list);
 462         p->pending = false;
 463
 464         return 0;
 465 }
 466
 467 static void uloop_handle_processes(void)
 468 {
 469         struct uloop_process *p, *tmp;
 470         pid_t pid;
 471         int ret;
 472
 473         do_sigchld = false;
 474
 475         while (1) {
 476                 pid = waitpid(-1, &ret, WNOHANG);
 477                 if (pid <= 0)
 478                         return;
 479
 480                 list_for_each_entry_safe(p, tmp, &processes, list) {
 481                         if (p->pid < pid)
 482                                 continue;
 483
 484                         if (p->pid > pid)
 485                                 break;
 486
 487                         uloop_process_delete(p);
 488                         p->cb(p, ret);
 489                 }
 490         }
 491
 492 }
 493
 494 static void uloop_handle_sigint(int signo)
 495 {
 496         uloop_cancelled = true;
 497 }
 498
 499 static void uloop_sigchld(int signo)
 500 {
 501         do_sigchld = true;
 502 }
 503
 504 static void uloop_setup_signals(void)
 505 {
 506         struct sigaction s;
 507
 508         memset(&s, 0, sizeof(struct sigaction));
 509         s.sa_handler = uloop_handle_sigint;
 510         s.sa_flags = 0;
 511         sigaction(SIGINT, &s, NULL);
 512
 513         if (uloop_handle_sigchld) {
 514                 s.sa_handler = uloop_sigchld;
 515                 sigaction(SIGCHLD, &s, NULL);
 516         }
 517 }
 518
 519 static int uloop_get_next_timeout(struct timeval *tv)
 520 {
 521         struct uloop_timeout *timeout;
 522         int diff;
 523
 524         if (list_empty(&timeouts))
 525                 return -1;
 526
 527         timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
 528         diff = tv_diff(&timeout->time, tv);
 529         if (diff < 0)
 530                 return 0;
 531
 532         return diff;
 533 }
 534
 535 static void uloop_process_timeouts(struct timeval *tv)
 536 {
 537         struct uloop_timeout *t;
 538
 539         while (!list_empty(&timeouts)) {
 540                 t = list_first_entry(&timeouts, struct uloop_timeout, list);
 541
 542                 if (tv_diff(&t->time, tv) > 0)
 543                         break;
 544
 545                 uloop_timeout_cancel(t);
 546                 if (t->cb)
 547                         t->cb(t);
 548         }
 549 }
 550
 551 static void uloop_clear_timeouts(void)
 552 {
 553         struct uloop_timeout *t, *tmp;
 554
 555         list_for_each_entry_safe(t, tmp, &timeouts, list)
 556                 uloop_timeout_cancel(t);
 557 }
 558
 559 static void uloop_clear_processes(void)
 560 {
 561         struct uloop_process *p, *tmp;
 562
 563         list_for_each_entry_safe(p, tmp, &processes, list)
 564                 uloop_process_delete(p);
 565 }
 566
 567 void uloop_run(void)
 568 {
 569         struct timeval tv;
 570
 571         uloop_setup_signals();
 572         while(!uloop_cancelled)
 573         {
 574                 uloop_gettime(&tv);
 575                 uloop_process_timeouts(&tv);
 576                 if (uloop_cancelled)
 577                         break;
 578
 579                 if (do_sigchld)
 580                         uloop_handle_processes();
 581                 uloop_run_events(uloop_get_next_timeout(&tv));
 582         }
 583 }
 584
 585 void uloop_done(void)
 586 {
 587         if (poll_fd < 0)
 588                 return;
 589
 590         close(poll_fd);
 591         poll_fd = -1;
 592
 593         uloop_clear_timeouts();
 594         uloop_clear_processes();
 595 }