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