1/*
2 * Copyright (c) 2010 Mark Heily <mark@heily.com>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17#include <errno.h>
18#include <fcntl.h>
19#include <stdlib.h>
20#include <stdio.h>
21#include <sys/socket.h>
22#include <unistd.h>
23
24#include "private.h"
25
26struct eventfd {
27    int fd[2];
28};
29
30struct eventfd *
31eventfd_create(void)
32{
33    struct eventfd *e;
34
35    e = malloc(sizeof(*e));
36    if (e == NULL)
37        return (NULL);
38
39    if (socketpair(AF_UNIX, SOCK_STREAM, 0, e->fd) < 0) {
40        free(e);
41        return (NULL);
42    }
43    if ((fcntl(e->fd[0], F_SETFL, O_NONBLOCK) < 0) ||
44            (fcntl(e->fd[1], F_SETFL, O_NONBLOCK) < 0)) {
45        free(e);
46        close(e->fd[0]);
47        close(e->fd[1]);
48        return (NULL);
49    }
50
51    return (e);
52}
53
54void
55eventfd_free(struct eventfd *e)
56{
57    close(e->fd[0]);
58    close(e->fd[1]);
59    free(e);
60}
61
62int
63eventfd_raise(struct eventfd *e)
64{
65    dbg_puts("raising event level");
66    if (write(e->fd[0], ".", 1) < 0) {
67        /* FIXME: handle EAGAIN and EINTR */
68        dbg_printf("write(2): %s", strerror(errno));
69        return (-1);
70    }
71    return (0);
72}
73
74int
75eventfd_lower(struct eventfd *e)
76{
77    char buf[1024];
78
79    /* Reset the counter */
80    dbg_puts("lowering event level");
81    if (read(e->fd[1], &buf, sizeof(buf)) < 0) {
82        /* FIXME: handle EAGAIN and EINTR */
83        /* FIXME: loop so as to consume all data.. may need mutex */
84        dbg_printf("read(2): %s", strerror(errno));
85        return (-1);
86    }
87    return (0);
88}
89
90int
91eventfd_reader(struct eventfd *e)
92{
93    return (e->fd[1]);
94}
95
96int
97eventfd_writer(struct eventfd *e)
98{
99    return (e->fd[0]);
100}
101