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