uloop-epoll.c

   1 /*
   2  * uloop - event loop implementation
   3  *
   4  * Copyright (C) 2010-2016 Felix Fietkau <nbd@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <sys/signalfd.h>
  20
  21 /**
  22  * FIXME: uClibc < 0.9.30.3 does not define EPOLLRDHUP for Linux >= 2.6.17
  23  */
  24 #ifndef EPOLLRDHUP
  25 #define EPOLLRDHUP 0x2000
  26 #endif
  27
  28 static void
  29 uloop_signal_fd_cb(struct uloop_fd *fd, unsigned int events)
  30 {
  31         struct signalfd_siginfo fdsi;
  32         struct sigaction act;
  33         int ret;
  34
  35 retry:
  36         ret = read(fd->fd, &fdsi, sizeof(fdsi));
  37         if (ret < 0 && errno == EINTR)
  38                 goto retry;
  39
  40         if (ret != sizeof(fdsi))
  41                 return;
  42
  43         switch (fdsi.ssi_signo) {
  44         case SIGQUIT:
  45         case SIGINT:
  46         case SIGTERM:
  47                 sigaction(fdsi.ssi_signo, NULL, &act);
  48                 if (act.sa_handler != SIG_IGN &&
  49                         act.sa_handler != SIG_DFL) {
  50                         act.sa_handler(fdsi.ssi_signo);
  51                         break;
  52                 }
  53
  54                 /* fall through */
  55         default:
  56                 uloop_handle_signal(fdsi.ssi_signo);
  57                 break;
  58         }
  59 }
  60
  61 static bool
  62 uloop_setup_signalfd(bool add)
  63 {
  64         static struct uloop_fd sfd = {
  65                 .cb = uloop_signal_fd_cb
  66         };
  67         static sigset_t prev_mask;
  68         sigset_t mask;
  69
  70         if (signal_fd < 0)
  71                 return false;
  72
  73         sigemptyset(&mask);
  74
  75         if (!add) {
  76                 uloop_fd_delete(&sfd);
  77                 sigprocmask(SIG_BLOCK, &prev_mask, NULL);
  78         } else {
  79                 sigaddset(&mask, SIGQUIT);
  80                 sigaddset(&mask, SIGINT);
  81                 sigaddset(&mask, SIGTERM);
  82                 sigaddset(&mask, SIGCHLD);
  83                 sigprocmask(SIG_BLOCK, &mask, &prev_mask);
  84
  85                 sfd.fd = signal_fd;
  86                 uloop_fd_add(&sfd, ULOOP_READ | ULOOP_EDGE_TRIGGER);
  87         }
  88
  89         if (signalfd(signal_fd, &mask, SFD_NONBLOCK | SFD_CLOEXEC) < 0) {
  90                 sigprocmask(SIG_BLOCK, &prev_mask, NULL);
  91                 return false;
  92         }
  93
  94         return true;
  95 }
  96
  97 int uloop_init(void)
  98 {
  99         sigset_t mask;
 100
 101         if (poll_fd >= 0)
 102                 return 0;
 103
 104         poll_fd = epoll_create(32);
 105         if (poll_fd < 0)
 106                 return -1;
 107
 108         fcntl(poll_fd, F_SETFD, fcntl(poll_fd, F_GETFD) | FD_CLOEXEC);
 109
 110         sigemptyset(&mask);
 111         signal_fd = signalfd(-1, &mask, SFD_NONBLOCK | SFD_CLOEXEC);
 112
 113         return 0;
 114 }
 115
 116 static int register_poll(struct uloop_fd *fd, unsigned int flags)
 117 {
 118         struct epoll_event ev;
 119         int op = fd->registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
 120
 121         memset(&ev, 0, sizeof(struct epoll_event));
 122
 123         if (flags & ULOOP_READ)
 124                 ev.events |= EPOLLIN | EPOLLRDHUP;
 125
 126         if (flags & ULOOP_WRITE)
 127                 ev.events |= EPOLLOUT;
 128
 129         if (flags & ULOOP_EDGE_TRIGGER)
 130                 ev.events |= EPOLLET;
 131
 132         ev.data.fd = fd->fd;
 133         ev.data.ptr = fd;
 134         fd->flags = flags;
 135
 136         return epoll_ctl(poll_fd, op, fd->fd, &ev);
 137 }
 138
 139 static struct epoll_event events[ULOOP_MAX_EVENTS];
 140
 141 static int __uloop_fd_delete(struct uloop_fd *sock)
 142 {
 143         sock->flags = 0;
 144         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 145 }
 146
 147 static int uloop_fetch_events(int timeout)
 148 {
 149         int n, nfds;
 150
 151         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
 152         for (n = 0; n < nfds; ++n) {
 153                 struct uloop_fd_event *cur = &cur_fds[n];
 154                 struct uloop_fd *u = events[n].data.ptr;
 155                 unsigned int ev = 0;
 156
 157                 cur->fd = u;
 158                 if (!u)
 159                         continue;
 160
 161                 if (events[n].events & (EPOLLERR|EPOLLHUP)) {
 162                         u->error = true;
 163                         if (!(u->flags & ULOOP_ERROR_CB))
 164                                 uloop_fd_delete(u);
 165                 }
 166
 167                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP))) {
 168                         cur->fd = NULL;
 169                         continue;
 170                 }
 171
 172                 if(events[n].events & EPOLLRDHUP)
 173                         u->eof = true;
 174
 175                 if(events[n].events & EPOLLIN)
 176                         ev |= ULOOP_READ;
 177
 178                 if(events[n].events & EPOLLOUT)
 179                         ev |= ULOOP_WRITE;
 180
 181                 cur->events = ev;
 182         }
 183
 184         return nfds;
 185 }