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