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 static int cur_fd, cur_nfds;
 205 static struct epoll_event events[ULOOP_MAX_EVENTS];
 206
 207 int uloop_fd_delete(struct uloop_fd *sock)
 208 {
 209         int i;
 210
 211         for (i = cur_fd + 1; i < cur_nfds; i++) {
 212                 if (events[i].data.ptr != sock)
 213                         continue;
 214
 215                 events[i].data.ptr = NULL;
 216         }
 217         sock->registered = false;
 218         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 219 }
 220
 221 static void uloop_run_events(int timeout)
 222 {
 223         int n, nfds;
 224
 225         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
 226         for(n = 0; n < nfds; ++n)
 227         {
 228                 struct uloop_fd *u = events[n].data.ptr;
 229                 unsigned int ev = 0;
 230
 231                 if (!u)
 232                         continue;
 233
 234                 if(events[n].events & (EPOLLERR|EPOLLHUP)) {
 235                         u->error = true;
 236                         uloop_fd_delete(u);
 237                 }
 238
 239                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP)))
 240                         continue;
 241
 242                 if(events[n].events & EPOLLRDHUP)
 243                         u->eof = true;
 244
 245                 if(events[n].events & EPOLLIN)
 246                         ev |= ULOOP_READ;
 247
 248                 if(events[n].events & EPOLLOUT)
 249                         ev |= ULOOP_WRITE;
 250
 251                 if(u->cb) {
 252                         cur_fd = n;
 253                         cur_nfds = nfds;
 254                         u->cb(u, ev);
 255                 }
 256         }
 257         cur_nfds = 0;
 258 }
 259
 260 #endif
 261
 262 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
 263 {
 264         unsigned int fl;
 265         int ret;
 266
 267         if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
 268                 fl = fcntl(sock->fd, F_GETFL, 0);
 269                 fl |= O_NONBLOCK;
 270                 fcntl(sock->fd, F_SETFL, fl);
 271         }
 272
 273         ret = register_poll(sock, flags);
 274         if (ret < 0)
 275                 goto out;
 276
 277         sock->registered = true;
 278         sock->eof = false;
 279
 280 out:
 281         return ret;
 282 }
 283
 284 static int tv_diff(struct timeval *t1, struct timeval *t2)
 285 {
 286         if (t1->tv_sec != t2->tv_sec)
 287                 return (t1->tv_sec - t2->tv_sec) * 1000;
 288         else
 289                 return (t1->tv_usec - t2->tv_usec) / 1000;
 290 }
 291
 292 int uloop_timeout_add(struct uloop_timeout *timeout)
 293 {
 294         struct uloop_timeout *tmp;
 295         struct list_head *h = &timeouts;
 296
 297         if (timeout->pending)
 298                 return -1;
 299
 300         list_for_each_entry(tmp, &timeouts, list) {
 301                 if (tv_diff(&tmp->time, &timeout->time) > 0) {
 302                         h = &tmp->list;
 303                         break;
 304                 }
 305         }
 306
 307         list_add_tail(&timeout->list, h);
 308         timeout->pending = true;
 309
 310         return 0;
 311 }
 312
 313 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 314 {
 315         struct timeval *time = &timeout->time;
 316
 317         if (timeout->pending)
 318                 uloop_timeout_cancel(timeout);
 319
 320         gettimeofday(&timeout->time, NULL);
 321
 322         time->tv_sec += msecs / 1000;
 323         time->tv_usec += msecs % 1000;
 324
 325         if (time->tv_usec > 1000000) {
 326                 time->tv_sec++;
 327                 time->tv_usec %= 100000;
 328         }
 329
 330         return uloop_timeout_add(timeout);
 331 }
 332
 333 int uloop_timeout_cancel(struct uloop_timeout *timeout)
 334 {
 335         if (!timeout->pending)
 336                 return -1;
 337
 338         list_del(&timeout->list);
 339         timeout->pending = false;
 340
 341         return 0;
 342 }
 343
 344 int uloop_process_add(struct uloop_process *p)
 345 {
 346         struct uloop_process *tmp;
 347         struct list_head *h = &processes;
 348
 349         if (p->pending)
 350                 return -1;
 351
 352         list_for_each_entry(tmp, &processes, list) {
 353                 if (tmp->pid > p->pid) {
 354                         h = &tmp->list;
 355                         break;
 356                 }
 357         }
 358
 359         list_add_tail(&p->list, h);
 360         p->pending = true;
 361
 362         return 0;
 363 }
 364
 365 int uloop_process_delete(struct uloop_process *p)
 366 {
 367         if (!p->pending)
 368                 return -1;
 369
 370         list_del(&p->list);
 371         p->pending = false;
 372
 373         return 0;
 374 }
 375
 376 static void uloop_handle_processes(void)
 377 {
 378         struct uloop_process *p, *tmp;
 379         pid_t pid;
 380         int ret;
 381
 382         do_sigchld = false;
 383
 384         while (1) {
 385                 pid = waitpid(-1, &ret, WNOHANG);
 386                 if (pid <= 0)
 387                         return;
 388
 389                 list_for_each_entry_safe(p, tmp, &processes, list) {
 390                         if (p->pid < pid)
 391                                 continue;
 392
 393                         if (p->pid > pid)
 394                                 break;
 395
 396                         uloop_process_delete(p);
 397                         p->cb(p, ret);
 398                 }
 399         }
 400
 401 }
 402
 403 static void uloop_handle_sigint(int signo)
 404 {
 405         uloop_cancelled = true;
 406 }
 407
 408 static void uloop_sigchld(int signo)
 409 {
 410         do_sigchld = true;
 411 }
 412
 413 static void uloop_setup_signals(void)
 414 {
 415         struct sigaction s;
 416
 417         memset(&s, 0, sizeof(struct sigaction));
 418         s.sa_handler = uloop_handle_sigint;
 419         s.sa_flags = 0;
 420         sigaction(SIGINT, &s, NULL);
 421
 422         if (uloop_handle_sigchld) {
 423                 s.sa_handler = uloop_sigchld;
 424                 sigaction(SIGCHLD, &s, NULL);
 425         }
 426 }
 427
 428 static int uloop_get_next_timeout(struct timeval *tv)
 429 {
 430         struct uloop_timeout *timeout;
 431         int diff;
 432
 433         if (list_empty(&timeouts))
 434                 return -1;
 435
 436         timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
 437         diff = tv_diff(&timeout->time, tv);
 438         if (diff < 0)
 439                 return 0;
 440
 441         return diff;
 442 }
 443
 444 static void uloop_process_timeouts(struct timeval *tv)
 445 {
 446         struct uloop_timeout *t, *tmp;
 447
 448         list_for_each_entry_safe(t, tmp, &timeouts, list) {
 449                 if (tv_diff(&t->time, tv) > 0)
 450                         break;
 451
 452                 uloop_timeout_cancel(t);
 453                 if (t->cb)
 454                         t->cb(t);
 455         }
 456 }
 457
 458 static void uloop_clear_timeouts(void)
 459 {
 460         struct uloop_timeout *t, *tmp;
 461
 462         list_for_each_entry_safe(t, tmp, &timeouts, list)
 463                 uloop_timeout_cancel(t);
 464 }
 465
 466 static void uloop_clear_processes(void)
 467 {
 468         struct uloop_process *p, *tmp;
 469
 470         list_for_each_entry_safe(p, tmp, &processes, list)
 471                 uloop_process_delete(p);
 472 }
 473
 474 void uloop_run(void)
 475 {
 476         struct timeval tv;
 477
 478         uloop_setup_signals();
 479         while(!uloop_cancelled)
 480         {
 481                 gettimeofday(&tv, NULL);
 482                 uloop_process_timeouts(&tv);
 483                 if (uloop_cancelled)
 484                         break;
 485
 486                 if (do_sigchld)
 487                         uloop_handle_processes();
 488                 uloop_run_events(uloop_get_next_timeout(&tv));
 489         }
 490 }
 491
 492 void uloop_done(void)
 493 {
 494         if (poll_fd < 0)
 495                 return;
 496
 497         close(poll_fd);
 498         poll_fd = -1;
 499
 500         uloop_clear_timeouts();
 501         uloop_clear_processes();
 502 }