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