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
  58 #ifdef USE_KQUEUE
  59
  60 int uloop_init(void)
  61 {
  62         if (poll_fd >= 0)
  63                 return 0;
  64
  65         poll_fd = kqueue();
  66         if (poll_fd < 0)
  67                 return -1;
  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 int register_poll(struct uloop_fd *fd, unsigned int flags)
  88 {
  89         struct timespec timeout = { 0, 0 };
  90         struct kevent ev[2];
  91         unsigned int changed;
  92         int nev = 0;
  93
  94         changed = fd->kqflags ^ flags;
  95         if (changed & ULOOP_EDGE_TRIGGER)
  96                 changed |= flags;
  97
  98         if (changed & ULOOP_READ) {
  99                 uint16_t kflags = get_flags(flags, ULOOP_READ);
 100                 EV_SET(&ev[nev++], fd->fd, EVFILT_READ, kflags, 0, 0, fd);
 101         }
 102
 103         if (changed & ULOOP_WRITE) {
 104                 uint16_t kflags = get_flags(flags, ULOOP_WRITE);
 105                 EV_SET(&ev[nev++], fd->fd, EVFILT_WRITE, kflags, 0, 0, fd);
 106         }
 107
 108         if (nev && (kevent(poll_fd, ev, nev, NULL, 0, &timeout) == -1))
 109                 return -1;
 110
 111         fd->kqflags = flags;
 112         return 0;
 113 }
 114
 115 int uloop_fd_delete(struct uloop_fd *sock)
 116 {
 117         sock->registered = false;
 118         return register_poll(sock, 0);
 119 }
 120
 121 static void uloop_run_events(int timeout)
 122 {
 123         struct kevent events[ULOOP_MAX_EVENTS];
 124         struct timespec ts;
 125         int nfds, n;
 126
 127         if (timeout > 0) {
 128                 ts.tv_sec = timeout / 1000;
 129                 ts.tv_nsec = (timeout % 1000) * 1000000;
 130         }
 131
 132         nfds = kevent(poll_fd, NULL, 0, events, ARRAY_SIZE(events), timeout > 0 ? &ts : NULL);
 133         for(n = 0; n < nfds; ++n)
 134         {
 135                 struct uloop_fd *u = events[n].udata;
 136                 unsigned int ev = 0;
 137
 138                 if(events[n].flags & EV_ERROR) {
 139                         u->error = true;
 140                         uloop_fd_delete(u);
 141                 }
 142
 143                 if(events[n].filter == EVFILT_READ)
 144                         ev |= ULOOP_READ;
 145                 else if (events[n].filter == EVFILT_WRITE)
 146                         ev |= ULOOP_WRITE;
 147
 148                 if(events[n].flags & EV_EOF)
 149                         u->eof = true;
 150                 else if (!ev)
 151                         continue;
 152
 153                 if(u->cb)
 154                         u->cb(u, ev);
 155         }
 156 }
 157
 158 #endif
 159
 160 #ifdef USE_EPOLL
 161
 162 /**
 163  * FIXME: uClibc < 0.9.30.3 does not define EPOLLRDHUP for Linux >= 2.6.17
 164  */
 165 #ifndef EPOLLRDHUP
 166 #define EPOLLRDHUP 0x2000
 167 #endif
 168
 169 int uloop_init(void)
 170 {
 171         if (poll_fd >= 0)
 172                 return 0;
 173
 174         poll_fd = epoll_create(32);
 175         if (poll_fd < 0)
 176                 return -1;
 177
 178         fcntl(poll_fd, F_SETFD, fcntl(poll_fd, F_GETFD) | FD_CLOEXEC);
 179         return 0;
 180 }
 181
 182 static int register_poll(struct uloop_fd *fd, unsigned int flags)
 183 {
 184         struct epoll_event ev;
 185         int op = fd->registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
 186
 187         memset(&ev, 0, sizeof(struct epoll_event));
 188
 189         if (flags & ULOOP_READ)
 190                 ev.events |= EPOLLIN | EPOLLRDHUP;
 191
 192         if (flags & ULOOP_WRITE)
 193                 ev.events |= EPOLLOUT;
 194
 195         if (flags & ULOOP_EDGE_TRIGGER)
 196                 ev.events |= EPOLLET;
 197
 198         ev.data.fd = fd->fd;
 199         ev.data.ptr = fd;
 200
 201         return epoll_ctl(poll_fd, op, fd->fd, &ev);
 202 }
 203
 204 int uloop_fd_delete(struct uloop_fd *sock)
 205 {
 206         sock->registered = false;
 207         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 208 }
 209
 210 static void uloop_run_events(int timeout)
 211 {
 212         struct epoll_event events[ULOOP_MAX_EVENTS];
 213         int nfds, n;
 214
 215         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
 216         for(n = 0; n < nfds; ++n)
 217         {
 218                 struct uloop_fd *u = events[n].data.ptr;
 219                 unsigned int ev = 0;
 220
 221                 if(events[n].events & EPOLLERR) {
 222                         u->error = true;
 223                         uloop_fd_delete(u);
 224                 }
 225
 226                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR)))
 227                         continue;
 228
 229                 if(events[n].events & EPOLLRDHUP)
 230                         u->eof = true;
 231
 232                 if(events[n].events & EPOLLIN)
 233                         ev |= ULOOP_READ;
 234
 235                 if(events[n].events & EPOLLOUT)
 236                         ev |= ULOOP_WRITE;
 237
 238                 if(u->cb)
 239                         u->cb(u, ev);
 240         }
 241 }
 242
 243 #endif
 244
 245 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
 246 {
 247         unsigned int fl;
 248         int ret;
 249
 250         if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
 251                 fl = fcntl(sock->fd, F_GETFL, 0);
 252                 fl |= O_NONBLOCK;
 253                 fcntl(sock->fd, F_SETFL, fl);
 254         }
 255
 256         ret = register_poll(sock, flags);
 257         if (ret < 0)
 258                 goto out;
 259
 260         sock->registered = true;
 261         sock->eof = false;
 262
 263 out:
 264         return ret;
 265 }
 266
 267 static int tv_diff(struct timeval *t1, struct timeval *t2)
 268 {
 269         if (t1->tv_sec != t2->tv_sec)
 270                 return (t1->tv_sec - t2->tv_sec) * 1000;
 271         else
 272                 return (t1->tv_usec - t2->tv_usec) / 1000;
 273 }
 274
 275 int uloop_timeout_add(struct uloop_timeout *timeout)
 276 {
 277         struct uloop_timeout *tmp;
 278         struct list_head *h = &timeouts;
 279
 280         if (timeout->pending)
 281                 return -1;
 282
 283         list_for_each_entry(tmp, &timeouts, list) {
 284                 if (tv_diff(&tmp->time, &timeout->time) > 0) {
 285                         h = &tmp->list;
 286                         break;
 287                 }
 288         }
 289
 290         list_add_tail(&timeout->list, h);
 291         timeout->pending = true;
 292
 293         return 0;
 294 }
 295
 296 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 297 {
 298         struct timeval *time = &timeout->time;
 299
 300         if (timeout->pending)
 301                 uloop_timeout_cancel(timeout);
 302
 303         gettimeofday(&timeout->time, NULL);
 304
 305         time->tv_sec += msecs / 1000;
 306         time->tv_usec += msecs % 1000;
 307
 308         if (time->tv_usec > 1000000) {
 309                 time->tv_sec++;
 310                 time->tv_usec %= 100000;
 311         }
 312
 313         return uloop_timeout_add(timeout);
 314 }
 315
 316 int uloop_timeout_cancel(struct uloop_timeout *timeout)
 317 {
 318         if (!timeout->pending)
 319                 return -1;
 320
 321         list_del(&timeout->list);
 322         timeout->pending = false;
 323
 324         return 0;
 325 }
 326
 327 int uloop_process_add(struct uloop_process *p)
 328 {
 329         struct uloop_process *tmp;
 330         struct list_head *h = &processes;
 331
 332         if (p->pending)
 333                 return -1;
 334
 335         list_for_each_entry(tmp, &processes, list) {
 336                 if (tmp->pid > p->pid) {
 337                         h = &tmp->list;
 338                         break;
 339                 }
 340         }
 341
 342         list_add_tail(&p->list, h);
 343         p->pending = true;
 344
 345         return 0;
 346 }
 347
 348 int uloop_process_delete(struct uloop_process *p)
 349 {
 350         if (!p->pending)
 351                 return -1;
 352
 353         list_del(&p->list);
 354         p->pending = false;
 355
 356         return 0;
 357 }
 358
 359 static void uloop_handle_processes(void)
 360 {
 361         struct uloop_process *p, *tmp;
 362         pid_t pid;
 363         int ret;
 364
 365         do_sigchld = false;
 366
 367         while (1) {
 368                 pid = waitpid(-1, &ret, WNOHANG);
 369                 if (pid <= 0)
 370                         return;
 371
 372                 list_for_each_entry_safe(p, tmp, &processes, list) {
 373                         if (p->pid < pid)
 374                                 continue;
 375
 376                         if (p->pid > pid)
 377                                 break;
 378
 379                         uloop_process_delete(p);
 380                         p->cb(p, ret);
 381                 }
 382         }
 383
 384 }
 385
 386 static void uloop_handle_sigint(int signo)
 387 {
 388         uloop_cancelled = true;
 389 }
 390
 391 static void uloop_sigchld(int signo)
 392 {
 393         do_sigchld = true;
 394 }
 395
 396 static void uloop_setup_signals(void)
 397 {
 398         struct sigaction s;
 399
 400         memset(&s, 0, sizeof(struct sigaction));
 401         s.sa_handler = uloop_handle_sigint;
 402         s.sa_flags = 0;
 403         sigaction(SIGINT, &s, NULL);
 404
 405         if (uloop_handle_sigchld) {
 406                 s.sa_handler = uloop_sigchld;
 407                 sigaction(SIGCHLD, &s, NULL);
 408         }
 409 }
 410
 411 static int uloop_get_next_timeout(struct timeval *tv)
 412 {
 413         struct uloop_timeout *timeout;
 414         int diff;
 415
 416         if (list_empty(&timeouts))
 417                 return -1;
 418
 419         timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
 420         diff = tv_diff(&timeout->time, tv);
 421         if (diff < 0)
 422                 return 0;
 423
 424         return diff;
 425 }
 426
 427 static void uloop_process_timeouts(struct timeval *tv)
 428 {
 429         struct uloop_timeout *t, *tmp;
 430
 431         list_for_each_entry_safe(t, tmp, &timeouts, list) {
 432                 if (tv_diff(&t->time, tv) > 0)
 433                         break;
 434
 435                 uloop_timeout_cancel(t);
 436                 if (t->cb)
 437                         t->cb(t);
 438         }
 439 }
 440
 441 void uloop_run(void)
 442 {
 443         struct timeval tv;
 444
 445         uloop_setup_signals();
 446         while(!uloop_cancelled)
 447         {
 448                 gettimeofday(&tv, NULL);
 449                 uloop_process_timeouts(&tv);
 450                 if (uloop_cancelled)
 451                         break;
 452
 453                 if (do_sigchld)
 454                         uloop_handle_processes();
 455                 uloop_run_events(uloop_get_next_timeout(&tv));
 456         }
 457 }
 458
 459 void uloop_done(void)
 460 {
 461         if (poll_fd < 0)
 462                 return;
 463
 464         close(poll_fd);
 465         poll_fd = -1;
 466 }