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         for (i = cur_fd + 1; i < cur_nfds; i++) {
 250                 if (events[i].data.ptr != sock)
 251                         continue;
 252
 253                 events[i].data.ptr = NULL;
 254         }
 255         sock->registered = false;
 256         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 257 }
 258
 259 static void uloop_run_events(int timeout)
 260 {
 261         int n, nfds;
 262
 263         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
 264         for(n = 0; n < nfds; ++n)
 265         {
 266                 struct uloop_fd *u = events[n].data.ptr;
 267                 unsigned int ev = 0;
 268
 269                 if (!u)
 270                         continue;
 271
 272                 if(events[n].events & (EPOLLERR|EPOLLHUP)) {
 273                         u->error = true;
 274                         uloop_fd_delete(u);
 275                 }
 276
 277                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP)))
 278                         continue;
 279
 280                 if(events[n].events & EPOLLRDHUP)
 281                         u->eof = true;
 282
 283                 if(events[n].events & EPOLLIN)
 284                         ev |= ULOOP_READ;
 285
 286                 if(events[n].events & EPOLLOUT)
 287                         ev |= ULOOP_WRITE;
 288
 289                 if(u->cb) {
 290                         cur_fd = n;
 291                         cur_nfds = nfds;
 292                         u->cb(u, ev);
 293                 }
 294         }
 295         cur_nfds = 0;
 296 }
 297
 298 #endif
 299
 300 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
 301 {
 302         unsigned int fl;
 303         int ret;
 304
 305         if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
 306                 fl = fcntl(sock->fd, F_GETFL, 0);
 307                 fl |= O_NONBLOCK;
 308                 fcntl(sock->fd, F_SETFL, fl);
 309         }
 310
 311         ret = register_poll(sock, flags);
 312         if (ret < 0)
 313                 goto out;
 314
 315         sock->registered = true;
 316         sock->eof = false;
 317
 318 out:
 319         return ret;
 320 }
 321
 322 static int tv_diff(struct timeval *t1, struct timeval *t2)
 323 {
 324         return
 325                 (t1->tv_sec - t2->tv_sec) * 1000 +
 326                 (t1->tv_usec - t2->tv_usec) / 1000;
 327 }
 328
 329 int uloop_timeout_add(struct uloop_timeout *timeout)
 330 {
 331         struct uloop_timeout *tmp;
 332         struct list_head *h = &timeouts;
 333
 334         if (timeout->pending)
 335                 return -1;
 336
 337         list_for_each_entry(tmp, &timeouts, list) {
 338                 if (tv_diff(&tmp->time, &timeout->time) > 0) {
 339                         h = &tmp->list;
 340                         break;
 341                 }
 342         }
 343
 344         list_add_tail(&timeout->list, h);
 345         timeout->pending = true;
 346
 347         return 0;
 348 }
 349
 350 static void uloop_gettime(struct timeval *tv)
 351 {
 352         struct timespec ts;
 353
 354         clock_gettime(CLOCK_MONOTONIC, &ts);
 355         tv->tv_sec = ts.tv_sec;
 356         tv->tv_usec = ts.tv_nsec / 1000;
 357 }
 358
 359 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 360 {
 361         struct timeval *time = &timeout->time;
 362
 363         if (timeout->pending)
 364                 uloop_timeout_cancel(timeout);
 365
 366         uloop_gettime(&timeout->time);
 367
 368         time->tv_sec += msecs / 1000;
 369         time->tv_usec += (msecs % 1000) * 1000;
 370
 371         if (time->tv_usec > 1000000) {
 372                 time->tv_sec++;
 373                 time->tv_usec %= 1000000;
 374         }
 375
 376         return uloop_timeout_add(timeout);
 377 }
 378
 379 int uloop_timeout_cancel(struct uloop_timeout *timeout)
 380 {
 381         if (!timeout->pending)
 382                 return -1;
 383
 384         list_del(&timeout->list);
 385         timeout->pending = false;
 386
 387         return 0;
 388 }
 389
 390 int uloop_process_add(struct uloop_process *p)
 391 {
 392         struct uloop_process *tmp;
 393         struct list_head *h = &processes;
 394
 395         if (p->pending)
 396                 return -1;
 397
 398         list_for_each_entry(tmp, &processes, list) {
 399                 if (tmp->pid > p->pid) {
 400                         h = &tmp->list;
 401                         break;
 402                 }
 403         }
 404
 405         list_add_tail(&p->list, h);
 406         p->pending = true;
 407
 408         return 0;
 409 }
 410
 411 int uloop_process_delete(struct uloop_process *p)
 412 {
 413         if (!p->pending)
 414                 return -1;
 415
 416         list_del(&p->list);
 417         p->pending = false;
 418
 419         return 0;
 420 }
 421
 422 static void uloop_handle_processes(void)
 423 {
 424         struct uloop_process *p, *tmp;
 425         pid_t pid;
 426         int ret;
 427
 428         do_sigchld = false;
 429
 430         while (1) {
 431                 pid = waitpid(-1, &ret, WNOHANG);
 432                 if (pid <= 0)
 433                         return;
 434
 435                 list_for_each_entry_safe(p, tmp, &processes, list) {
 436                         if (p->pid < pid)
 437                                 continue;
 438
 439                         if (p->pid > pid)
 440                                 break;
 441
 442                         uloop_process_delete(p);
 443                         p->cb(p, ret);
 444                 }
 445         }
 446
 447 }
 448
 449 static void uloop_handle_sigint(int signo)
 450 {
 451         uloop_cancelled = true;
 452 }
 453
 454 static void uloop_sigchld(int signo)
 455 {
 456         do_sigchld = true;
 457 }
 458
 459 static void uloop_setup_signals(void)
 460 {
 461         struct sigaction s;
 462
 463         memset(&s, 0, sizeof(struct sigaction));
 464         s.sa_handler = uloop_handle_sigint;
 465         s.sa_flags = 0;
 466         sigaction(SIGINT, &s, NULL);
 467
 468         if (uloop_handle_sigchld) {
 469                 s.sa_handler = uloop_sigchld;
 470                 sigaction(SIGCHLD, &s, NULL);
 471         }
 472 }
 473
 474 static int uloop_get_next_timeout(struct timeval *tv)
 475 {
 476         struct uloop_timeout *timeout;
 477         int diff;
 478
 479         if (list_empty(&timeouts))
 480                 return -1;
 481
 482         timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
 483         diff = tv_diff(&timeout->time, tv);
 484         if (diff < 0)
 485                 return 0;
 486
 487         return diff;
 488 }
 489
 490 static void uloop_process_timeouts(struct timeval *tv)
 491 {
 492         struct uloop_timeout *t;
 493
 494         while (!list_empty(&timeouts)) {
 495                 t = list_first_entry(&timeouts, struct uloop_timeout, list);
 496
 497                 if (tv_diff(&t->time, tv) > 0)
 498                         break;
 499
 500                 uloop_timeout_cancel(t);
 501                 if (t->cb)
 502                         t->cb(t);
 503         }
 504 }
 505
 506 static void uloop_clear_timeouts(void)
 507 {
 508         struct uloop_timeout *t, *tmp;
 509
 510         list_for_each_entry_safe(t, tmp, &timeouts, list)
 511                 uloop_timeout_cancel(t);
 512 }
 513
 514 static void uloop_clear_processes(void)
 515 {
 516         struct uloop_process *p, *tmp;
 517
 518         list_for_each_entry_safe(p, tmp, &processes, list)
 519                 uloop_process_delete(p);
 520 }
 521
 522 void uloop_run(void)
 523 {
 524         struct timeval tv;
 525
 526         uloop_setup_signals();
 527         while(!uloop_cancelled)
 528         {
 529                 uloop_gettime(&tv);
 530                 uloop_process_timeouts(&tv);
 531                 if (uloop_cancelled)
 532                         break;
 533
 534                 if (do_sigchld)
 535                         uloop_handle_processes();
 536                 uloop_run_events(uloop_get_next_timeout(&tv));
 537         }
 538 }
 539
 540 void uloop_done(void)
 541 {
 542         if (poll_fd < 0)
 543                 return;
 544
 545         close(poll_fd);
 546         poll_fd = -1;
 547
 548         uloop_clear_timeouts();
 549         uloop_clear_processes();
 550 }