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         int ret;
  33
  34 retry:
  35         ret = read(fd->fd, &fdsi, sizeof(fdsi));
  36         if (ret < 0 && errno == EINTR)
  37                 goto retry;
  38
  39         if (ret != sizeof(fdsi))
  40                 return;
  41
  42         uloop_handle_signal(fdsi.ssi_signo);
  43 }
  44
  45 static bool
  46 uloop_setup_signalfd(bool add)
  47 {
  48         static struct uloop_fd sfd = {
  49                 .cb = uloop_signal_fd_cb
  50         };
  51         static sigset_t prev_mask;
  52         sigset_t mask;
  53
  54         if (signal_fd < 0)
  55                 return false;
  56
  57         sigemptyset(&mask);
  58
  59         if (!add) {
  60                 uloop_fd_delete(&sfd);
  61                 sigprocmask(SIG_SETMASK, &prev_mask, NULL);
  62         } else {
  63                 sigaddset(&mask, SIGQUIT);
  64                 sigaddset(&mask, SIGINT);
  65                 sigaddset(&mask, SIGTERM);
  66                 sigaddset(&mask, SIGCHLD);
  67                 sigprocmask(SIG_BLOCK, &mask, &prev_mask);
  68
  69                 sfd.fd = signal_fd;
  70                 uloop_fd_add(&sfd, ULOOP_READ | ULOOP_EDGE_TRIGGER);
  71         }
  72
  73         if (signalfd(signal_fd, &mask, SFD_NONBLOCK | SFD_CLOEXEC) < 0) {
  74                 sigprocmask(SIG_BLOCK, &prev_mask, NULL);
  75                 return false;
  76         }
  77
  78         return true;
  79 }
  80
  81 int uloop_init(void)
  82 {
  83         sigset_t mask;
  84
  85         if (poll_fd >= 0)
  86                 return 0;
  87
  88         poll_fd = epoll_create(32);
  89         if (poll_fd < 0)
  90                 return -1;
  91
  92         fcntl(poll_fd, F_SETFD, fcntl(poll_fd, F_GETFD) | FD_CLOEXEC);
  93
  94         sigemptyset(&mask);
  95         signal_fd = signalfd(-1, &mask, SFD_NONBLOCK | SFD_CLOEXEC);
  96
  97         return 0;
  98 }
  99
 100 static int register_poll(struct uloop_fd *fd, unsigned int flags)
 101 {
 102         struct epoll_event ev;
 103         int op = fd->registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
 104
 105         memset(&ev, 0, sizeof(struct epoll_event));
 106
 107         if (flags & ULOOP_READ)
 108                 ev.events |= EPOLLIN | EPOLLRDHUP;
 109
 110         if (flags & ULOOP_WRITE)
 111                 ev.events |= EPOLLOUT;
 112
 113         if (flags & ULOOP_EDGE_TRIGGER)
 114                 ev.events |= EPOLLET;
 115
 116         ev.data.fd = fd->fd;
 117         ev.data.ptr = fd;
 118         fd->flags = flags;
 119
 120         return epoll_ctl(poll_fd, op, fd->fd, &ev);
 121 }
 122
 123 static struct epoll_event events[ULOOP_MAX_EVENTS];
 124
 125 static int __uloop_fd_delete(struct uloop_fd *sock)
 126 {
 127         sock->flags = 0;
 128         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 129 }
 130
 131 static int uloop_fetch_events(int timeout)
 132 {
 133         int n, nfds;
 134
 135         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
 136         for (n = 0; n < nfds; ++n) {
 137                 struct uloop_fd_event *cur = &cur_fds[n];
 138                 struct uloop_fd *u = events[n].data.ptr;
 139                 unsigned int ev = 0;
 140
 141                 cur->fd = u;
 142                 if (!u)
 143                         continue;
 144
 145                 if (events[n].events & (EPOLLERR|EPOLLHUP)) {
 146                         u->error = true;
 147                         if (!(u->flags & ULOOP_ERROR_CB))
 148                                 uloop_fd_delete(u);
 149                 }
 150
 151                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP))) {
 152                         cur->fd = NULL;
 153                         continue;
 154                 }
 155
 156                 if(events[n].events & EPOLLRDHUP)
 157                         u->eof = true;
 158
 159                 if(events[n].events & EPOLLIN)
 160                         ev |= ULOOP_READ;
 161
 162                 if(events[n].events & EPOLLOUT)
 163                         ev |= ULOOP_WRITE;
 164
 165                 cur->events = ev;
 166         }
 167
 168         return nfds;
 169 }