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
  43
  44 #ifndef ARRAY_SIZE
  45 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
  46 #endif
  47 #define ULOOP_MAX_EVENTS 10
  48
  49 static struct list_head timeouts = LIST_HEAD_INIT(timeouts);
  50 static struct list_head processes = LIST_HEAD_INIT(processes);
  51
  52 static int poll_fd = -1;
  53 bool uloop_cancelled = false;
  54 bool uloop_handle_sigchld = true;
  55 static bool do_sigchld = false;
  56
  57 #ifdef USE_KQUEUE
  58
  59 int uloop_init(void)
  60 {
  61         if (poll_fd >= 0)
  62                 return 0;
  63
  64         poll_fd = kqueue();
  65         if (poll_fd < 0)
  66                 return -1;
  67
  68         return 0;
  69 }
  70
  71
  72 static uint16_t get_flags(unsigned int flags, unsigned int mask)
  73 {
  74         uint16_t kflags = 0;
  75
  76         if (!(flags & mask))
  77                 return EV_DELETE;
  78
  79         kflags = EV_ADD;
  80         if (flags & ULOOP_EDGE_TRIGGER)
  81                 kflags |= EV_CLEAR;
  82
  83         return kflags;
  84 }
  85
  86 static int register_poll(struct uloop_fd *fd, unsigned int flags)
  87 {
  88         struct timespec timeout = { 0, 0 };
  89         struct kevent ev[2];
  90         unsigned int changed;
  91         int nev = 0;
  92
  93         changed = fd->kqflags ^ flags;
  94         if (changed & ULOOP_EDGE_TRIGGER)
  95                 changed |= flags;
  96
  97         if (changed & ULOOP_READ) {
  98                 uint16_t kflags = get_flags(flags, ULOOP_READ);
  99                 EV_SET(&ev[nev++], fd->fd, EVFILT_READ, kflags, 0, 0, fd);
 100         }
 101
 102         if (changed & ULOOP_WRITE) {
 103                 uint16_t kflags = get_flags(flags, ULOOP_WRITE);
 104                 EV_SET(&ev[nev++], fd->fd, EVFILT_WRITE, kflags, 0, 0, fd);
 105         }
 106
 107         if (nev && (kevent(poll_fd, ev, nev, NULL, 0, &timeout) == -1))
 108                 return -1;
 109
 110         fd->kqflags = flags;
 111         return 0;
 112 }
 113
 114 int uloop_fd_delete(struct uloop_fd *sock)
 115 {
 116         sock->registered = false;
 117         return register_poll(sock, 0);
 118 }
 119
 120 static void uloop_run_events(int timeout)
 121 {
 122         struct kevent events[ULOOP_MAX_EVENTS];
 123         struct timespec ts;
 124         int nfds, n;
 125
 126         if (timeout > 0) {
 127                 ts.tv_sec = timeout / 1000;
 128                 ts.tv_nsec = (timeout % 1000) * 1000000;
 129         }
 130
 131         nfds = kevent(poll_fd, NULL, 0, events, ARRAY_SIZE(events), timeout > 0 ? &ts : NULL);
 132         for(n = 0; n < nfds; ++n)
 133         {
 134                 struct uloop_fd *u = events[n].udata;
 135                 unsigned int ev = 0;
 136
 137                 if(events[n].flags & EV_ERROR) {
 138                         u->error = true;
 139                         uloop_fd_delete(u);
 140                 }
 141
 142                 if(events[n].filter == EVFILT_READ)
 143                         ev |= ULOOP_READ;
 144                 else if (events[n].filter == EVFILT_WRITE)
 145                         ev |= ULOOP_WRITE;
 146
 147                 if(events[n].flags & EV_EOF)
 148                         u->eof = true;
 149                 else if (!ev)
 150                         continue;
 151
 152                 if(u->cb)
 153                         u->cb(u, ev);
 154         }
 155 }
 156
 157 #endif
 158
 159 #ifdef USE_EPOLL
 160
 161 /**
 162  * FIXME: uClibc < 0.9.30.3 does not define EPOLLRDHUP for Linux >= 2.6.17
 163  */
 164 #ifndef EPOLLRDHUP
 165 #define EPOLLRDHUP 0x2000
 166 #endif
 167
 168 int uloop_init(void)
 169 {
 170         if (poll_fd >= 0)
 171                 return 0;
 172
 173         poll_fd = epoll_create(32);
 174         if (poll_fd < 0)
 175                 return -1;
 176
 177         fcntl(poll_fd, F_SETFD, fcntl(poll_fd, F_GETFD) | FD_CLOEXEC);
 178         return 0;
 179 }
 180
 181 static int register_poll(struct uloop_fd *fd, unsigned int flags)
 182 {
 183         struct epoll_event ev;
 184         int op = fd->registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
 185
 186         memset(&ev, 0, sizeof(struct epoll_event));
 187
 188         if (flags & ULOOP_READ)
 189                 ev.events |= EPOLLIN | EPOLLRDHUP;
 190
 191         if (flags & ULOOP_WRITE)
 192                 ev.events |= EPOLLOUT;
 193
 194         if (flags & ULOOP_EDGE_TRIGGER)
 195                 ev.events |= EPOLLET;
 196
 197         ev.data.fd = fd->fd;
 198         ev.data.ptr = fd;
 199
 200         return epoll_ctl(poll_fd, op, fd->fd, &ev);
 201 }
 202
 203 int uloop_fd_delete(struct uloop_fd *sock)
 204 {
 205         sock->registered = false;
 206         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 207 }
 208
 209 static void uloop_run_events(int timeout)
 210 {
 211         struct epoll_event events[ULOOP_MAX_EVENTS];
 212         int nfds, n;
 213
 214         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
 215         for(n = 0; n < nfds; ++n)
 216         {
 217                 struct uloop_fd *u = events[n].data.ptr;
 218                 unsigned int ev = 0;
 219
 220                 if(events[n].events & EPOLLERR) {
 221                         u->error = true;
 222                         uloop_fd_delete(u);
 223                 }
 224
 225                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR)))
 226                         continue;
 227
 228                 if(events[n].events & EPOLLRDHUP)
 229                         u->eof = true;
 230
 231                 if(events[n].events & EPOLLIN)
 232                         ev |= ULOOP_READ;
 233
 234                 if(events[n].events & EPOLLOUT)
 235                         ev |= ULOOP_WRITE;
 236
 237                 if(u->cb)
 238                         u->cb(u, ev);
 239         }
 240 }
 241
 242 #endif
 243
 244 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
 245 {
 246         unsigned int fl;
 247         int ret;
 248
 249         if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
 250                 fl = fcntl(sock->fd, F_GETFL, 0);
 251                 fl |= O_NONBLOCK;
 252                 fcntl(sock->fd, F_SETFL, fl);
 253         }
 254
 255         ret = register_poll(sock, flags);
 256         if (ret < 0)
 257                 goto out;
 258
 259         sock->registered = true;
 260         sock->eof = false;
 261
 262 out:
 263         return ret;
 264 }
 265
 266 static int tv_diff(struct timeval *t1, struct timeval *t2)
 267 {
 268         if (t1->tv_sec != t2->tv_sec)
 269                 return (t1->tv_sec - t2->tv_sec) * 1000;
 270         else
 271                 return (t1->tv_usec - t2->tv_usec) / 1000;
 272 }
 273
 274 int uloop_timeout_add(struct uloop_timeout *timeout)
 275 {
 276         struct uloop_timeout *tmp;
 277         struct list_head *h = &timeouts;
 278
 279         if (timeout->pending)
 280                 return -1;
 281
 282         list_for_each_entry(tmp, &timeouts, list) {
 283                 if (tv_diff(&tmp->time, &timeout->time) > 0) {
 284                         h = &tmp->list;
 285                         break;
 286                 }
 287         }
 288
 289         list_add_tail(&timeout->list, h);
 290         timeout->pending = true;
 291
 292         return 0;
 293 }
 294
 295 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 296 {
 297         struct timeval *time = &timeout->time;
 298
 299         if (timeout->pending)
 300                 uloop_timeout_cancel(timeout);
 301
 302         gettimeofday(&timeout->time, NULL);
 303
 304         time->tv_sec += msecs / 1000;
 305         time->tv_usec += msecs % 1000;
 306
 307         if (time->tv_usec > 1000000) {
 308                 time->tv_sec++;
 309                 time->tv_usec %= 100000;
 310         }
 311
 312         return uloop_timeout_add(timeout);
 313 }
 314
 315 int uloop_timeout_cancel(struct uloop_timeout *timeout)
 316 {
 317         if (!timeout->pending)
 318                 return -1;
 319
 320         list_del(&timeout->list);
 321         timeout->pending = false;
 322
 323         return 0;
 324 }
 325
 326 int uloop_process_add(struct uloop_process *p)
 327 {
 328         struct uloop_process *tmp;
 329         struct list_head *h = &processes;
 330
 331         if (p->pending)
 332                 return -1;
 333
 334         list_for_each_entry(tmp, &processes, list) {
 335                 if (tmp->pid > p->pid) {
 336                         h = &tmp->list;
 337                         break;
 338                 }
 339         }
 340
 341         list_add_tail(&p->list, h);
 342         p->pending = true;
 343
 344         return 0;
 345 }
 346
 347 int uloop_process_delete(struct uloop_process *p)
 348 {
 349         if (!p->pending)
 350                 return -1;
 351
 352         list_del(&p->list);
 353         p->pending = false;
 354
 355         return 0;
 356 }
 357
 358 static void uloop_handle_processes(void)
 359 {
 360         struct uloop_process *p, *tmp;
 361         pid_t pid;
 362         int ret;
 363
 364         do_sigchld = false;
 365
 366         while (1) {
 367                 pid = waitpid(-1, &ret, WNOHANG);
 368                 if (pid <= 0)
 369                         return;
 370
 371                 list_for_each_entry_safe(p, tmp, &processes, list) {
 372                         if (p->pid < pid)
 373                                 continue;
 374
 375                         if (p->pid > pid)
 376                                 break;
 377
 378                         uloop_process_delete(p);
 379                         p->cb(p, ret);
 380                 }
 381         }
 382
 383 }
 384
 385 static void uloop_handle_sigint(int signo)
 386 {
 387         uloop_cancelled = true;
 388 }
 389
 390 static void uloop_sigchld(int signo)
 391 {
 392         do_sigchld = true;
 393 }
 394
 395 static void uloop_setup_signals(void)
 396 {
 397         struct sigaction s;
 398
 399         memset(&s, 0, sizeof(struct sigaction));
 400         s.sa_handler = uloop_handle_sigint;
 401         s.sa_flags = 0;
 402         sigaction(SIGINT, &s, NULL);
 403
 404         if (uloop_handle_sigchld) {
 405                 s.sa_handler = uloop_sigchld;
 406                 sigaction(SIGCHLD, &s, NULL);
 407         }
 408 }
 409
 410 static int uloop_get_next_timeout(struct timeval *tv)
 411 {
 412         struct uloop_timeout *timeout;
 413         int diff;
 414
 415         if (list_empty(&timeouts))
 416                 return -1;
 417
 418         timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
 419         diff = tv_diff(&timeout->time, tv);
 420         if (diff < 0)
 421                 return 0;
 422
 423         return diff;
 424 }
 425
 426 static void uloop_process_timeouts(struct timeval *tv)
 427 {
 428         struct uloop_timeout *t, *tmp;
 429
 430         list_for_each_entry_safe(t, tmp, &timeouts, list) {
 431                 if (tv_diff(&t->time, tv) > 0)
 432                         break;
 433
 434                 uloop_timeout_cancel(t);
 435                 if (t->cb)
 436                         t->cb(t);
 437         }
 438 }
 439
 440 void uloop_run(void)
 441 {
 442         struct timeval tv;
 443
 444         uloop_setup_signals();
 445         while(!uloop_cancelled)
 446         {
 447                 gettimeofday(&tv, NULL);
 448                 uloop_process_timeouts(&tv);
 449                 if (uloop_cancelled)
 450                         break;
 451
 452                 if (do_sigchld)
 453                         uloop_handle_processes();
 454                 uloop_run_events(uloop_get_next_timeout(&tv));
 455         }
 456 }
 457
 458 void uloop_done(void)
 459 {
 460         if (poll_fd < 0)
 461                 return;
 462
 463         close(poll_fd);
 464         poll_fd = -1;
 465 }