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