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         fl = fcntl(sock->fd, F_GETFL, 0);
  61         fl |= O_NONBLOCK;
  62         fcntl(sock->fd, F_SETFL, fl);
  63
  64         memset(&ev, 0, sizeof(struct epoll_event));
  65
  66         if (flags & ULOOP_READ)
  67                 ev.events |= EPOLLIN | EPOLLRDHUP;
  68
  69         if (flags & ULOOP_WRITE)
  70                 ev.events |= EPOLLOUT;
  71
  72         if (flags & ULOOP_EDGE_TRIGGER)
  73                 ev.events |= EPOLLET;
  74
  75         ev.data.fd = sock->fd;
  76         ev.data.ptr = sock;
  77
  78         ret = epoll_ctl(epoll_fd, op, sock->fd, &ev);
  79         if (ret < 0)
  80                 goto out;
  81
  82         sock->registered = true;
  83         sock->eof = false;
  84
  85 out:
  86         return ret;
  87 }
  88
  89 int uloop_fd_delete(struct uloop_fd *sock)
  90 {
  91         sock->registered = false;
  92         return epoll_ctl(epoll_fd, EPOLL_CTL_DEL, sock->fd, 0);
  93 }
  94
  95 static int tv_diff(struct timeval *t1, struct timeval *t2)
  96 {
  97         if (t1->tv_sec != t2->tv_sec)
  98                 return (t1->tv_sec - t2->tv_sec) * 1000;
  99         else
 100                 return (t1->tv_usec - t2->tv_usec) / 1000;
 101 }
 102
 103 int uloop_timeout_add(struct uloop_timeout *timeout)
 104 {
 105         struct uloop_timeout **head = &first_timeout;
 106         struct uloop_timeout *prev = NULL;
 107
 108         if (timeout->pending)
 109                 return -1;
 110
 111         while (*head) {
 112                 if (tv_diff(&(*head)->time, &timeout->time) > 0)
 113                         break;
 114
 115                 prev = *head;
 116                 head = &(*head)->next;
 117         }
 118
 119         timeout->prev = prev;
 120         timeout->next = *head;
 121         if (timeout->next)
 122                 timeout->next->prev = timeout;
 123         *head = timeout;
 124         timeout->pending = true;
 125
 126         return 0;
 127 }
 128
 129 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 130 {
 131         struct timeval *time = &timeout->time;
 132
 133         if (timeout->pending)
 134                 uloop_timeout_cancel(timeout);
 135
 136         gettimeofday(&timeout->time, NULL);
 137
 138         time->tv_sec += msecs / 1000;
 139         time->tv_usec += msecs % 1000;
 140
 141         if (time->tv_usec > 1000000) {
 142                 time->tv_sec++;
 143                 time->tv_usec %= 100000;
 144         }
 145
 146         return uloop_timeout_add(timeout);
 147 }
 148
 149 int uloop_timeout_cancel(struct uloop_timeout *timeout)
 150 {
 151         if (!timeout->pending)
 152                 return -1;
 153
 154         if (timeout->prev)
 155                 timeout->prev->next = timeout->next;
 156         else
 157                 first_timeout = timeout->next;
 158
 159         if (timeout->next)
 160                 timeout->next->prev = timeout->prev;
 161
 162         timeout->pending = false;
 163
 164         return 0;
 165 }
 166
 167 static void uloop_handle_sigint(int signo)
 168 {
 169         cancel = true;
 170 }
 171
 172 static void uloop_setup_signals(void)
 173 {
 174         struct sigaction s;
 175         memset(&s, 0, sizeof(struct sigaction));
 176         s.sa_handler = uloop_handle_sigint;
 177         s.sa_flags = 0;
 178         sigaction(SIGINT, &s, NULL);
 179 }
 180
 181 static int uloop_get_next_timeout(struct timeval *tv)
 182 {
 183         int diff;
 184
 185         if (!first_timeout)
 186                 return -1;
 187
 188         diff = tv_diff(&first_timeout->time, tv);
 189         if (diff < 0)
 190                 return 0;
 191
 192         return diff;
 193 }
 194
 195 static void uloop_process_timeouts(struct timeval *tv)
 196 {
 197         struct uloop_timeout *timeout;
 198
 199         while (first_timeout) {
 200                 if (tv_diff(&first_timeout->time, tv) > 0)
 201                         break;
 202
 203                 timeout = first_timeout;
 204                 uloop_timeout_cancel(timeout);
 205                 if (timeout->cb)
 206                         timeout->cb(timeout);
 207         }
 208 }
 209
 210 void uloop_end(void)
 211 {
 212         cancel = true;
 213 }
 214
 215 int uloop_init(void)
 216 {
 217         epoll_fd = epoll_create(32);
 218         if (epoll_fd < 0)
 219                 return -1;
 220
 221         fcntl(epoll_fd, F_SETFD, fcntl(epoll_fd, F_GETFD) | FD_CLOEXEC);
 222         return 0;
 223 }
 224
 225 void uloop_run(void)
 226 {
 227         struct epoll_event events[10];
 228         struct timeval tv;
 229         int timeout;
 230         int nfds, n;
 231
 232         uloop_setup_signals();
 233         while(!cancel)
 234         {
 235                 gettimeofday(&tv, NULL);
 236                 uloop_process_timeouts(&tv);
 237                 timeout = uloop_get_next_timeout(&tv);
 238                 nfds = epoll_wait(epoll_fd, events, ARRAY_SIZE(events), timeout);
 239                 for(n = 0; n < nfds; ++n)
 240                 {
 241                         struct uloop_fd *u = events[n].data.ptr;
 242                         unsigned int ev = 0;
 243
 244                         if(events[n].events & EPOLLERR) {
 245                                 u->error = true;
 246                                 uloop_fd_delete(u);
 247                         }
 248
 249                         if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR)))
 250                                 continue;
 251
 252                         if(events[n].events & EPOLLRDHUP)
 253                                 u->eof = true;
 254
 255                         if(events[n].events & EPOLLIN)
 256                                 ev |= ULOOP_READ;
 257
 258                         if(events[n].events & EPOLLOUT)
 259                                 ev |= ULOOP_WRITE;
 260
 261                         if(u->cb)
 262                                 u->cb(u, ev);
 263                 }
 264         }
 265 }
 266
 267 void uloop_done(void)
 268 {
 269         close(epoll_fd);
 270 }