1 /*
2 * libev poll fd activity backend
3 *
4 * Copyright (c) 2007,2008,2009,2010,2011,2016,2019 Marc Alexander Lehmann <libev@schmorp.de>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without modifica-
8 * tion, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
21 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26 * OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Alternatively, the contents of this file may be used under the terms of
29 * the GNU General Public License ("GPL") version 2 or any later version,
30 * in which case the provisions of the GPL are applicable instead of
31 * the above. If you wish to allow the use of your version of this file
32 * only under the terms of the GPL and not to allow others to use your
33 * version of this file under the BSD license, indicate your decision
34 * by deleting the provisions above and replace them with the notice
35 * and other provisions required by the GPL. If you do not delete the
36 * provisions above, a recipient may use your version of this file under
37 * either the BSD or the GPL.
38 */
39
40 #include <poll.h>
41
42 inline_size
43 void
array_needsize_pollidx(int * base,int offset,int count)44 array_needsize_pollidx (int *base, int offset, int count)
45 {
46 /* using memset (.., -1, ...) is tempting, we we try
47 * to be ultraportable
48 */
49 base += offset;
50 while (count--)
51 *base++ = -1;
52 }
53
54 static void
poll_modify(EV_P_ int fd,int oev,int nev)55 poll_modify (EV_P_ int fd, int oev, int nev)
56 {
57 int idx;
58
59 if (oev == nev)
60 return;
61
62 array_needsize (int, pollidxs, pollidxmax, fd + 1, array_needsize_pollidx);
63
64 idx = pollidxs [fd];
65
66 if (idx < 0) /* need to allocate a new pollfd */
67 {
68 pollidxs [fd] = idx = pollcnt++;
69 array_needsize (struct pollfd, polls, pollmax, pollcnt, array_needsize_noinit);
70 polls [idx].fd = fd;
71 }
72
73 assert (polls [idx].fd == fd);
74
75 if (nev)
76 polls [idx].events =
77 (nev & EV_READ ? POLLIN : 0)
78 | (nev & EV_WRITE ? POLLOUT : 0);
79 else /* remove pollfd */
80 {
81 pollidxs [fd] = -1;
82
83 if (ecb_expect_true (idx < --pollcnt))
84 {
85 polls [idx] = polls [pollcnt];
86 pollidxs [polls [idx].fd] = idx;
87 }
88 }
89 }
90
91 static void
poll_poll(EV_P_ ev_tstamp timeout)92 poll_poll (EV_P_ ev_tstamp timeout)
93 {
94 struct pollfd *p;
95 int res;
96
97 EV_RELEASE_CB;
98 res = poll (polls, pollcnt, EV_TS_TO_MSEC (timeout));
99 EV_ACQUIRE_CB;
100
101 if (ecb_expect_false (res < 0))
102 {
103 if (errno == EBADF)
104 fd_ebadf (EV_A);
105 else if (errno == ENOMEM && !syserr_cb)
106 fd_enomem (EV_A);
107 else if (errno != EINTR)
108 ev_syserr ("(libev) poll");
109 }
110 else
111 for (p = polls; res; ++p)
112 {
113 assert (("libev: poll returned illegal result, broken BSD kernel?", p < polls + pollcnt));
114
115 if (ecb_expect_false (p->revents)) /* this expect is debatable */
116 {
117 --res;
118
119 if (ecb_expect_false (p->revents & POLLNVAL))
120 {
121 assert (("libev: poll found invalid fd in poll set", 0));
122 fd_kill (EV_A_ p->fd);
123 }
124 else
125 fd_event (
126 EV_A_
127 p->fd,
128 (p->revents & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)
129 | (p->revents & (POLLIN | POLLERR | POLLHUP) ? EV_READ : 0)
130 );
131 }
132 }
133 }
134
135 inline_size
136 int
poll_init(EV_P_ int flags)137 poll_init (EV_P_ int flags)
138 {
139 backend_mintime = EV_TS_CONST (1e-3);
140 backend_modify = poll_modify;
141 backend_poll = poll_poll;
142
143 pollidxs = 0; pollidxmax = 0;
144 polls = 0; pollmax = 0; pollcnt = 0;
145
146 return EVBACKEND_POLL;
147 }
148
149 inline_size
150 void
poll_destroy(EV_P)151 poll_destroy (EV_P)
152 {
153 ev_free (pollidxs);
154 ev_free (polls);
155 }
156
157