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 #include <sys/epoll.h>
  25
  26 #include <unistd.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <errno.h>
  30 #include <poll.h>
  31 #include <string.h>
  32 #include <fcntl.h>
  33 #include <signal.h>
  34 #include <stdbool.h>
  35
  36 #include "uloop.h"
  37
  38 /**
  39  * FIXME: uClibc < 0.9.30.3 does not define EPOLLRDHUP for Linux >= 2.6.17
  40  */
  41 #ifndef EPOLLRDHUP
  42 #define EPOLLRDHUP 0x2000
  43 #endif
  44
  45 #ifndef ARRAY_SIZE
  46 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
  47 #endif
  48
  49 struct uloop_timeout *first_timeout;
  50 static int epoll_fd;
  51 static bool cancel;
  52
  53 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
  54 {
  55         struct epoll_event ev;
  56         int op = sock->registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
  57         unsigned int fl;
  58         int ret;
  59
  60         if (!sock->registered) {
  61                 fl = fcntl(sock->fd, F_GETFL, 0);
  62                 fl |= O_NONBLOCK;
  63                 fcntl(sock->fd, F_SETFL, fl);
  64         }
  65
  66         memset(&ev, 0, sizeof(struct epoll_event));
  67
  68         if (flags & ULOOP_READ)
  69                 ev.events |= EPOLLIN | EPOLLRDHUP;
  70
  71         if (flags & ULOOP_WRITE)
  72                 ev.events |= EPOLLOUT;
  73
  74         if (flags & ULOOP_EDGE_TRIGGER)
  75                 ev.events |= EPOLLET;
  76
  77         ev.data.fd = sock->fd;
  78         ev.data.ptr = sock;
  79
  80         ret = epoll_ctl(epoll_fd, op, sock->fd, &ev);
  81         if (ret < 0)
  82                 goto out;
  83
  84         sock->registered = true;
  85         sock->eof = false;
  86
  87 out:
  88         return ret;
  89 }
  90
  91 int uloop_fd_delete(struct uloop_fd *sock)
  92 {
  93         sock->registered = false;
  94         return epoll_ctl(epoll_fd, EPOLL_CTL_DEL, sock->fd, 0);
  95 }
  96
  97 static int tv_diff(struct timeval *t1, struct timeval *t2)
  98 {
  99         if (t1->tv_sec != t2->tv_sec)
 100                 return (t1->tv_sec - t2->tv_sec) * 1000;
 101         else
 102                 return (t1->tv_usec - t2->tv_usec) / 1000;
 103 }
 104
 105 int uloop_timeout_add(struct uloop_timeout *timeout)
 106 {
 107         struct uloop_timeout **head = &first_timeout;
 108         struct uloop_timeout *prev = NULL;
 109
 110         if (timeout->pending)
 111                 return -1;
 112
 113         while (*head) {
 114                 if (tv_diff(&(*head)->time, &timeout->time) > 0)
 115                         break;
 116
 117                 prev = *head;
 118                 head = &(*head)->next;
 119         }
 120
 121         timeout->prev = prev;
 122         timeout->next = *head;
 123         if (timeout->next)
 124                 timeout->next->prev = timeout;
 125         *head = timeout;
 126         timeout->pending = true;
 127
 128         return 0;
 129 }
 130
 131 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 132 {
 133         struct timeval *time = &timeout->time;
 134
 135         if (timeout->pending)
 136                 uloop_timeout_cancel(timeout);
 137
 138         gettimeofday(&timeout->time, NULL);
 139
 140         time->tv_sec += msecs / 1000;
 141         time->tv_usec += msecs % 1000;
 142
 143         if (time->tv_usec > 1000000) {
 144                 time->tv_sec++;
 145                 time->tv_usec %= 100000;
 146         }
 147
 148         return uloop_timeout_add(timeout);
 149 }
 150
 151 int uloop_timeout_cancel(struct uloop_timeout *timeout)
 152 {
 153         if (!timeout->pending)
 154                 return -1;
 155
 156         if (timeout->prev)
 157                 timeout->prev->next = timeout->next;
 158         else
 159                 first_timeout = timeout->next;
 160
 161         if (timeout->next)
 162                 timeout->next->prev = timeout->prev;
 163
 164         timeout->pending = false;
 165
 166         return 0;
 167 }
 168
 169 static void uloop_handle_sigint(int signo)
 170 {
 171         cancel = true;
 172 }
 173
 174 static void uloop_setup_signals(void)
 175 {
 176         struct sigaction s;
 177         memset(&s, 0, sizeof(struct sigaction));
 178         s.sa_handler = uloop_handle_sigint;
 179         s.sa_flags = 0;
 180         sigaction(SIGINT, &s, NULL);
 181 }
 182
 183 static int uloop_get_next_timeout(struct timeval *tv)
 184 {
 185         int diff;
 186
 187         if (!first_timeout)
 188                 return -1;
 189
 190         diff = tv_diff(&first_timeout->time, tv);
 191         if (diff < 0)
 192                 return 0;
 193
 194         return diff;
 195 }
 196
 197 static void uloop_process_timeouts(struct timeval *tv)
 198 {
 199         struct uloop_timeout *timeout;
 200
 201         while (first_timeout) {
 202                 if (tv_diff(&first_timeout->time, tv) > 0)
 203                         break;
 204
 205                 timeout = first_timeout;
 206                 uloop_timeout_cancel(timeout);
 207                 if (timeout->cb)
 208                         timeout->cb(timeout);
 209         }
 210 }
 211
 212 void uloop_end(void)
 213 {
 214         cancel = true;
 215 }
 216
 217 int uloop_init(void)
 218 {
 219         epoll_fd = epoll_create(32);
 220         if (epoll_fd < 0)
 221                 return -1;
 222
 223         fcntl(epoll_fd, F_SETFD, fcntl(epoll_fd, F_GETFD) | FD_CLOEXEC);
 224         return 0;
 225 }
 226
 227 void uloop_run(void)
 228 {
 229         struct epoll_event events[10];
 230         struct timeval tv;
 231         int timeout;
 232         int nfds, n;
 233
 234         uloop_setup_signals();
 235         while(!cancel)
 236         {
 237                 gettimeofday(&tv, NULL);
 238                 uloop_process_timeouts(&tv);
 239                 timeout = uloop_get_next_timeout(&tv);
 240                 nfds = epoll_wait(epoll_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(events[n].events & EPOLLERR) {
 247                                 u->error = true;
 248                                 uloop_fd_delete(u);
 249                         }
 250
 251                         if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR)))
 252                                 continue;
 253
 254                         if(events[n].events & EPOLLRDHUP)
 255                                 u->eof = true;
 256
 257                         if(events[n].events & EPOLLIN)
 258                                 ev |= ULOOP_READ;
 259
 260                         if(events[n].events & EPOLLOUT)
 261                                 ev |= ULOOP_WRITE;
 262
 263                         if(u->cb)
 264                                 u->cb(u, ev);
 265                 }
 266         }
 267 }
 268
 269 void uloop_done(void)
 270 {
 271         close(epoll_fd);
 272 }