uloop.c

   1 /*
   2  *   Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
   3  *   Copyright (C) 2010 John Crispin <blogic@openwrt.org>
   4  *   Copyright (C) 2010 Steven Barth <steven@midlink.org>
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
  19  *
  20  */
  21
  22 #include <sys/time.h>
  23 #include <sys/types.h>
  24
  25 #include <unistd.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <errno.h>
  29 #include <poll.h>
  30 #include <string.h>
  31 #include <fcntl.h>
  32 #include <stdbool.h>
  33
  34 #include "uloop.h"
  35 #include "utils.h"
  36
  37 #ifdef USE_KQUEUE
  38 #include <sys/event.h>
  39 #endif
  40 #ifdef USE_EPOLL
  41 #include <sys/epoll.h>
  42 #endif
  43 #include <sys/wait.h>
  44
  45 #define ULOOP_MAX_EVENTS 10
  46
  47 static struct list_head timeouts = LIST_HEAD_INIT(timeouts);
  48 static struct list_head processes = LIST_HEAD_INIT(processes);
  49
  50 static int poll_fd = -1;
  51 bool uloop_cancelled = false;
  52 bool uloop_handle_sigchld = true;
  53 static bool do_sigchld = false;
  54 static int cur_fd, cur_nfds;
  55
  56 #ifdef USE_KQUEUE
  57
  58 int uloop_init(void)
  59 {
  60         struct timespec timeout = { 0, 0 };
  61         struct kevent ev = {};
  62
  63         if (poll_fd >= 0)
  64                 return 0;
  65
  66         poll_fd = kqueue();
  67         if (poll_fd < 0)
  68                 return -1;
  69
  70         EV_SET(&ev, SIGCHLD, EVFILT_SIGNAL, EV_ADD, 0, 0, 0);
  71         kevent(poll_fd, &ev, 1, NULL, 0, &timeout);
  72
  73         return 0;
  74 }
  75
  76
  77 static uint16_t get_flags(unsigned int flags, unsigned int mask)
  78 {
  79         uint16_t kflags = 0;
  80
  81         if (!(flags & mask))
  82                 return EV_DELETE;
  83
  84         kflags = EV_ADD;
  85         if (flags & ULOOP_EDGE_TRIGGER)
  86                 kflags |= EV_CLEAR;
  87
  88         return kflags;
  89 }
  90
  91 static struct kevent events[ULOOP_MAX_EVENTS];
  92
  93 static int register_kevent(struct uloop_fd *fd, unsigned int flags)
  94 {
  95         struct timespec timeout = { 0, 0 };
  96         struct kevent ev[2];
  97         int nev = 0;
  98         unsigned int fl = 0;
  99         uint16_t kflags;
 100
 101         if (flags & ULOOP_EDGE_DEFER)
 102                 flags &= ~ULOOP_EDGE_TRIGGER;
 103
 104         kflags = get_flags(flags, ULOOP_READ);
 105         EV_SET(&ev[nev++], fd->fd, EVFILT_READ, kflags, 0, 0, fd);
 106
 107         kflags = get_flags(flags, ULOOP_WRITE);
 108         EV_SET(&ev[nev++], fd->fd, EVFILT_WRITE, kflags, 0, 0, fd);
 109
 110         if (!flags)
 111                 fl |= EV_DELETE;
 112
 113         if (kevent(poll_fd, ev, nev, NULL, fl, &timeout) == -1)
 114                 return -1;
 115
 116         return 0;
 117 }
 118
 119 static int register_poll(struct uloop_fd *fd, unsigned int flags)
 120 {
 121         if (flags & ULOOP_EDGE_TRIGGER)
 122                 flags |= ULOOP_EDGE_DEFER;
 123         else
 124                 flags &= ~ULOOP_EDGE_DEFER;
 125
 126         fd->flags = flags;
 127         return register_kevent(fd, flags);
 128 }
 129
 130 int uloop_fd_delete(struct uloop_fd *sock)
 131 {
 132         int i;
 133
 134         for (i = cur_fd + 1; i < cur_nfds; i++) {
 135                 if (events[i].udata != sock)
 136                         continue;
 137
 138                 events[i].udata = NULL;
 139         }
 140
 141         sock->registered = false;
 142         return register_poll(sock, 0);
 143 }
 144
 145 static void uloop_run_events(int timeout)
 146 {
 147         struct timespec ts;
 148         int nfds, n;
 149
 150         if (timeout >= 0) {
 151                 ts.tv_sec = timeout / 1000;
 152                 ts.tv_nsec = (timeout % 1000) * 1000000;
 153         }
 154
 155         nfds = kevent(poll_fd, NULL, 0, events, ARRAY_SIZE(events), timeout >= 0 ? &ts : NULL);
 156         for(n = 0; n < nfds; ++n)
 157         {
 158                 struct uloop_fd *u = events[n].udata;
 159                 unsigned int ev = 0;
 160
 161                 if (!u)
 162                         continue;
 163
 164                 if (events[n].flags & EV_ERROR) {
 165                         u->error = true;
 166                         uloop_fd_delete(u);
 167                 }
 168
 169                 if(events[n].filter == EVFILT_READ)
 170                         ev |= ULOOP_READ;
 171                 else if (events[n].filter == EVFILT_WRITE)
 172                         ev |= ULOOP_WRITE;
 173
 174                 if (events[n].flags & EV_EOF)
 175                         u->eof = true;
 176                 else if (!ev)
 177                         continue;
 178
 179                 if (u->cb) {
 180                         cur_fd = n;
 181                         cur_nfds = nfds;
 182                         u->cb(u, ev);
 183                         if (u->flags & ULOOP_EDGE_DEFER) {
 184                                 u->flags &= ~ULOOP_EDGE_DEFER;
 185                                 register_kevent(u, u->flags);
 186                         }
 187                 }
 188         }
 189         cur_nfds = 0;
 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
 235         return epoll_ctl(poll_fd, op, fd->fd, &ev);
 236 }
 237
 238 static struct epoll_event events[ULOOP_MAX_EVENTS];
 239
 240 int uloop_fd_delete(struct uloop_fd *sock)
 241 {
 242         int i;
 243
 244         for (i = cur_fd + 1; i < cur_nfds; i++) {
 245                 if (events[i].data.ptr != sock)
 246                         continue;
 247
 248                 events[i].data.ptr = NULL;
 249         }
 250         sock->registered = false;
 251         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 252 }
 253
 254 static void uloop_run_events(int timeout)
 255 {
 256         int n, nfds;
 257
 258         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
 259         for(n = 0; n < nfds; ++n)
 260         {
 261                 struct uloop_fd *u = events[n].data.ptr;
 262                 unsigned int ev = 0;
 263
 264                 if (!u)
 265                         continue;
 266
 267                 if(events[n].events & (EPOLLERR|EPOLLHUP)) {
 268                         u->error = true;
 269                         uloop_fd_delete(u);
 270                 }
 271
 272                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP)))
 273                         continue;
 274
 275                 if(events[n].events & EPOLLRDHUP)
 276                         u->eof = true;
 277
 278                 if(events[n].events & EPOLLIN)
 279                         ev |= ULOOP_READ;
 280
 281                 if(events[n].events & EPOLLOUT)
 282                         ev |= ULOOP_WRITE;
 283
 284                 if(u->cb) {
 285                         cur_fd = n;
 286                         cur_nfds = nfds;
 287                         u->cb(u, ev);
 288                 }
 289         }
 290         cur_nfds = 0;
 291 }
 292
 293 #endif
 294
 295 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
 296 {
 297         unsigned int fl;
 298         int ret;
 299
 300         if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
 301                 fl = fcntl(sock->fd, F_GETFL, 0);
 302                 fl |= O_NONBLOCK;
 303                 fcntl(sock->fd, F_SETFL, fl);
 304         }
 305
 306         ret = register_poll(sock, flags);
 307         if (ret < 0)
 308                 goto out;
 309
 310         sock->registered = true;
 311         sock->eof = false;
 312
 313 out:
 314         return ret;
 315 }
 316
 317 static int tv_diff(struct timeval *t1, struct timeval *t2)
 318 {
 319         return
 320                 (t1->tv_sec - t2->tv_sec) * 1000 +
 321                 (t1->tv_usec - t2->tv_usec) / 1000;
 322 }
 323
 324 int uloop_timeout_add(struct uloop_timeout *timeout)
 325 {
 326         struct uloop_timeout *tmp;
 327         struct list_head *h = &timeouts;
 328
 329         if (timeout->pending)
 330                 return -1;
 331
 332         list_for_each_entry(tmp, &timeouts, list) {
 333                 if (tv_diff(&tmp->time, &timeout->time) > 0) {
 334                         h = &tmp->list;
 335                         break;
 336                 }
 337         }
 338
 339         list_add_tail(&timeout->list, h);
 340         timeout->pending = true;
 341
 342         return 0;
 343 }
 344
 345 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 346 {
 347         struct timeval *time = &timeout->time;
 348
 349         if (timeout->pending)
 350                 uloop_timeout_cancel(timeout);
 351
 352         gettimeofday(&timeout->time, NULL);
 353
 354         time->tv_sec += msecs / 1000;
 355         time->tv_usec += (msecs % 1000) * 1000;
 356
 357         if (time->tv_usec > 1000000) {
 358                 time->tv_sec++;
 359                 time->tv_usec %= 1000000;
 360         }
 361
 362         return uloop_timeout_add(timeout);
 363 }
 364
 365 int uloop_timeout_cancel(struct uloop_timeout *timeout)
 366 {
 367         if (!timeout->pending)
 368                 return -1;
 369
 370         list_del(&timeout->list);
 371         timeout->pending = false;
 372
 373         return 0;
 374 }
 375
 376 int uloop_process_add(struct uloop_process *p)
 377 {
 378         struct uloop_process *tmp;
 379         struct list_head *h = &processes;
 380
 381         if (p->pending)
 382                 return -1;
 383
 384         list_for_each_entry(tmp, &processes, list) {
 385                 if (tmp->pid > p->pid) {
 386                         h = &tmp->list;
 387                         break;
 388                 }
 389         }
 390
 391         list_add_tail(&p->list, h);
 392         p->pending = true;
 393
 394         return 0;
 395 }
 396
 397 int uloop_process_delete(struct uloop_process *p)
 398 {
 399         if (!p->pending)
 400                 return -1;
 401
 402         list_del(&p->list);
 403         p->pending = false;
 404
 405         return 0;
 406 }
 407
 408 static void uloop_handle_processes(void)
 409 {
 410         struct uloop_process *p, *tmp;
 411         pid_t pid;
 412         int ret;
 413
 414         do_sigchld = false;
 415
 416         while (1) {
 417                 pid = waitpid(-1, &ret, WNOHANG);
 418                 if (pid <= 0)
 419                         return;
 420
 421                 list_for_each_entry_safe(p, tmp, &processes, list) {
 422                         if (p->pid < pid)
 423                                 continue;
 424
 425                         if (p->pid > pid)
 426                                 break;
 427
 428                         uloop_process_delete(p);
 429                         p->cb(p, ret);
 430                 }
 431         }
 432
 433 }
 434
 435 static void uloop_handle_sigint(int signo)
 436 {
 437         uloop_cancelled = true;
 438 }
 439
 440 static void uloop_sigchld(int signo)
 441 {
 442         do_sigchld = true;
 443 }
 444
 445 static void uloop_setup_signals(void)
 446 {
 447         struct sigaction s;
 448
 449         memset(&s, 0, sizeof(struct sigaction));
 450         s.sa_handler = uloop_handle_sigint;
 451         s.sa_flags = 0;
 452         sigaction(SIGINT, &s, NULL);
 453
 454         if (uloop_handle_sigchld) {
 455                 s.sa_handler = uloop_sigchld;
 456                 sigaction(SIGCHLD, &s, NULL);
 457         }
 458 }
 459
 460 static int uloop_get_next_timeout(struct timeval *tv)
 461 {
 462         struct uloop_timeout *timeout;
 463         int diff;
 464
 465         if (list_empty(&timeouts))
 466                 return -1;
 467
 468         timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
 469         diff = tv_diff(&timeout->time, tv);
 470         if (diff < 0)
 471                 return 0;
 472
 473         return diff;
 474 }
 475
 476 static void uloop_process_timeouts(struct timeval *tv)
 477 {
 478         struct uloop_timeout *t;
 479
 480         while (!list_empty(&timeouts)) {
 481                 t = list_first_entry(&timeouts, struct uloop_timeout, list);
 482
 483                 if (tv_diff(&t->time, tv) > 0)
 484                         break;
 485
 486                 uloop_timeout_cancel(t);
 487                 if (t->cb)
 488                         t->cb(t);
 489         }
 490 }
 491
 492 static void uloop_clear_timeouts(void)
 493 {
 494         struct uloop_timeout *t, *tmp;
 495
 496         list_for_each_entry_safe(t, tmp, &timeouts, list)
 497                 uloop_timeout_cancel(t);
 498 }
 499
 500 static void uloop_clear_processes(void)
 501 {
 502         struct uloop_process *p, *tmp;
 503
 504         list_for_each_entry_safe(p, tmp, &processes, list)
 505                 uloop_process_delete(p);
 506 }
 507
 508 void uloop_run(void)
 509 {
 510         struct timeval tv;
 511
 512         uloop_setup_signals();
 513         while(!uloop_cancelled)
 514         {
 515                 gettimeofday(&tv, NULL);
 516                 uloop_process_timeouts(&tv);
 517                 if (uloop_cancelled)
 518                         break;
 519
 520                 if (do_sigchld)
 521                         uloop_handle_processes();
 522                 uloop_run_events(uloop_get_next_timeout(&tv));
 523         }
 524 }
 525
 526 void uloop_done(void)
 527 {
 528         if (poll_fd < 0)
 529                 return;
 530
 531         close(poll_fd);
 532         poll_fd = -1;
 533
 534         uloop_clear_timeouts();
 535         uloop_clear_processes();
 536 }