1 /*
2  * Copyright (C) 2008 The Android Open Source Project
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *  * Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  *  * Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *    the documentation and/or other materials provided with the
13  *    distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #pragma once
30 
31 /**
32  * @file sys/select.h
33  * @brief Wait for events on a set of file descriptors (but use <poll.h> instead).
34  */
35 
36 #include <sys/cdefs.h>
37 #include <sys/types.h>
38 
39 #include <linux/time.h>
40 #include <signal.h>
41 
42 __BEGIN_DECLS
43 
44 typedef unsigned long fd_mask;
45 
46 /**
47  * The limit on the largest fd that can be used with this API.
48  * Use <poll.h> instead.
49  */
50 #define FD_SETSIZE 1024
51 #define NFDBITS (8 * sizeof(fd_mask))
52 
53 /**
54  * The type of a file descriptor set. Limited to 1024 fds.
55  * Use <poll.h> instead.
56  */
57 typedef struct {
58   fd_mask fds_bits[FD_SETSIZE/NFDBITS];
59 } fd_set;
60 
61 #define __FDELT(fd) ((fd) / NFDBITS)
62 #define __FDMASK(fd) (1UL << ((fd) % NFDBITS))
63 #define __FDS_BITS(type,set) (__BIONIC_CAST(static_cast, type, set)->fds_bits)
64 
65 /* Inline loop so we don't have to declare memset. */
66 #define FD_ZERO(set) \
67   do { \
68     size_t __i; \
69     for (__i = 0; __i < sizeof(fd_set)/sizeof(fd_mask); ++__i) { \
70       (set)->fds_bits[__i] = 0; \
71     } \
72   } while (0)
73 
74 void __FD_CLR_chk(int, fd_set*, size_t) __INTRODUCED_IN(21);
75 void __FD_SET_chk(int, fd_set*, size_t) __INTRODUCED_IN(21);
76 int __FD_ISSET_chk(int, const fd_set*, size_t) __INTRODUCED_IN(21);
77 
78 #define __FD_CLR(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] &= ~__FDMASK(fd))
79 #define __FD_SET(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] |= __FDMASK(fd))
80 #define __FD_ISSET(fd, set) ((__FDS_BITS(const fd_set*,set)[__FDELT(fd)] & __FDMASK(fd)) != 0)
81 
82 #if __ANDROID_API__ >= 21
83 
84 /** Removes `fd` from the given set. Use <poll.h> instead. */
85 #define FD_CLR(fd, set) __FD_CLR_chk(fd, set, __bos(set))
86 /** Adds `fd` to the given set. Use <poll.h> instead. */
87 #define FD_SET(fd, set) __FD_SET_chk(fd, set, __bos(set))
88 /** Tests whether `fd` is in the given set. Use <poll.h> instead. */
89 #define FD_ISSET(fd, set) __FD_ISSET_chk(fd, set, __bos(set))
90 
91 #else
92 
93 /** Removes `fd` from the given set. Use <poll.h> instead. */
94 #define FD_CLR(fd, set) __FD_CLR(fd, set)
95 /** Adds `fd` to the given set. Use <poll.h> instead. */
96 #define FD_SET(fd, set) __FD_SET(fd, set)
97 /** Tests whether `fd` is in the given set. Use <poll.h> instead. */
98 #define FD_ISSET(fd, set) __FD_ISSET(fd, set)
99 
100 #endif /* __ANDROID_API >= 21 */
101 
102 /**
103  * [select(2)](http://man7.org/linux/man-pages/man2/select.2.html) waits on a
104  * set of file descriptors. Use poll() instead.
105  *
106  * Returns the number of ready file descriptors on success, 0 for timeout,
107  * and returns -1 and sets `errno` on failure.
108  */
109 int select(int __fd_count, fd_set* __read_fds, fd_set* __write_fds, fd_set* __exception_fds, struct timeval* __timeout);
110 
111 /**
112  * [pselect(2)](http://man7.org/linux/man-pages/man2/select.2.html) waits on a
113  * set of file descriptors. Use ppoll() instead.
114  *
115  * Returns the number of ready file descriptors on success, 0 for timeout,
116  * and returns -1 and sets `errno` on failure.
117  */
118 int pselect(int __fd_count, fd_set* __read_fds, fd_set* __write_fds, fd_set* __exception_fds, const struct timespec* __timeout, const sigset_t* __mask);
119 
120 /**
121  * [pselect64(2)](http://man7.org/linux/man-pages/man2/select.2.html) waits on a
122  * set of file descriptors. Use ppoll64() instead.
123  *
124  * Returns the number of ready file descriptors on success, 0 for timeout,
125  * and returns -1 and sets `errno` on failure.
126  *
127  * Available since API level 28.
128  */
129 int pselect64(int __fd_count, fd_set* __read_fds, fd_set* __write_fds, fd_set* __exception_fds, const struct timespec* __timeout, const sigset64_t* __mask) __INTRODUCED_IN(28);
130 
131 __END_DECLS
132