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 fd_set. 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 * The underlying system calls do not have this limit, 56 * and callers can allocate their own sets with calloc(). 57 * 58 * Use <poll.h> instead. 59 */ 60 typedef struct { 61 fd_mask fds_bits[FD_SETSIZE/NFDBITS]; 62 } fd_set; 63 64 #define __FDELT(fd) ((fd) / NFDBITS) 65 #define __FDMASK(fd) (1UL << ((fd) % NFDBITS)) 66 #define __FDS_BITS(type, set) (__BIONIC_CAST(static_cast, type, set)->fds_bits) 67 68 void __FD_CLR_chk(int, fd_set* _Nonnull , size_t); 69 void __FD_SET_chk(int, fd_set* _Nonnull, size_t); 70 int __FD_ISSET_chk(int, const fd_set* _Nonnull, size_t); 71 72 /** FD_CLR() with no bounds checking for users that allocated their own set. */ 73 #define __FD_CLR(fd, set) (__FDS_BITS(fd_set*, set)[__FDELT(fd)] &= ~__FDMASK(fd)) 74 /** FD_SET() with no bounds checking for users that allocated their own set. */ 75 #define __FD_SET(fd, set) (__FDS_BITS(fd_set*, set)[__FDELT(fd)] |= __FDMASK(fd)) 76 /** FD_ISSET() with no bounds checking for users that allocated their own set. */ 77 #define __FD_ISSET(fd, set) ((__FDS_BITS(const fd_set*, set)[__FDELT(fd)] & __FDMASK(fd)) != 0) 78 79 /** Removes all 1024 fds from the given set. Use <poll.h> instead. */ 80 #define FD_ZERO(set) __builtin_memset(set, 0, sizeof(*__BIONIC_CAST(static_cast, const fd_set*, set))) 81 82 /** Removes `fd` from the given set. Limited to fds under 1024. Use <poll.h> instead. */ 83 #define FD_CLR(fd, set) __FD_CLR_chk(fd, set, __bos(set)) 84 /** Adds `fd` to the given set. Limited to fds under 1024. Use <poll.h> instead. */ 85 #define FD_SET(fd, set) __FD_SET_chk(fd, set, __bos(set)) 86 /** Tests whether `fd` is in the given set. Limited to fds under 1024. Use <poll.h> instead. */ 87 #define FD_ISSET(fd, set) __FD_ISSET_chk(fd, set, __bos(set)) 88 89 /** 90 * [select(2)](https://man7.org/linux/man-pages/man2/select.2.html) waits on a 91 * set of file descriptors. 92 * 93 * Use poll() instead. 94 * 95 * Returns the number of ready file descriptors on success, 0 for timeout, 96 * and returns -1 and sets `errno` on failure. 97 */ 98 int select(int __max_fd_plus_one, fd_set* _Nullable __read_fds, fd_set* _Nullable __write_fds, fd_set* _Nullable __exception_fds, struct timeval* _Nullable __timeout); 99 100 /** 101 * [pselect(2)](https://man7.org/linux/man-pages/man2/select.2.html) waits on a 102 * set of file descriptors. 103 * 104 * Use ppoll() 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 pselect(int __max_fd_plus_one, fd_set* _Nullable __read_fds, fd_set* _Nullable __write_fds, fd_set* _Nullable __exception_fds, const struct timespec* _Nullable __timeout, const sigset_t* _Nullable __mask); 110 111 /** 112 * [pselect64(2)](https://man7.org/linux/man-pages/man2/select.2.html) waits on a 113 * set of file descriptors. 114 * 115 * Use ppoll64() instead. 116 * 117 * Returns the number of ready file descriptors on success, 0 for timeout, 118 * and returns -1 and sets `errno` on failure. 119 * 120 * Available since API level 28. 121 */ 122 123 #if __BIONIC_AVAILABILITY_GUARD(28) 124 int pselect64(int __max_fd_plus_one, fd_set* _Nullable __read_fds, fd_set* _Nullable __write_fds, fd_set* _Nullable __exception_fds, const struct timespec* _Nullable __timeout, const sigset64_t* _Nullable __mask) __INTRODUCED_IN(28); 125 #endif /* __BIONIC_AVAILABILITY_GUARD(28) */ 126 127 128 __END_DECLS 129