select.h

  1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
  2
  3#include "../nolibc.h"
  4
  5#ifndef _NOLIBC_SYS_SELECT_H
  6#define _NOLIBC_SYS_SELECT_H
  7
  8#include <linux/time.h>
  9#include <linux/unistd.h>
 10
 11/* commonly an fd_set represents 256 FDs */
 12#ifndef FD_SETSIZE
 13#define FD_SETSIZE     256
 14#endif
 15
 16#define FD_SETIDXMASK (8 * sizeof(unsigned long))
 17#define FD_SETBITMASK (8 * sizeof(unsigned long)-1)
 18
 19/* for select() */
 20typedef struct {
 21	unsigned long fds[(FD_SETSIZE + FD_SETBITMASK) / FD_SETIDXMASK];
 22} fd_set;
 23
 24#define FD_CLR(fd, set) do {						\
 25		fd_set *__set = (set);					\
 26		int __fd = (fd);					\
 27		if (__fd >= 0)						\
 28			__set->fds[__fd / FD_SETIDXMASK] &=		\
 29				~(1U << (__fd & FD_SETBITMASK));	\
 30	} while (0)
 31
 32#define FD_SET(fd, set) do {						\
 33		fd_set *__set = (set);					\
 34		int __fd = (fd);					\
 35		if (__fd >= 0)						\
 36			__set->fds[__fd / FD_SETIDXMASK] |=		\
 37				1 << (__fd & FD_SETBITMASK);		\
 38	} while (0)
 39
 40#define FD_ISSET(fd, set) ({						\
 41			fd_set *__set = (set);				\
 42			int __fd = (fd);				\
 43		int __r = 0;						\
 44		if (__fd >= 0)						\
 45			__r = !!(__set->fds[__fd / FD_SETIDXMASK] &	\
 461U << (__fd & FD_SETBITMASK));						\
 47		__r;							\
 48	})
 49
 50#define FD_ZERO(set) do {						\
 51		fd_set *__set = (set);					\
 52		int __idx;						\
 53		int __size = (FD_SETSIZE+FD_SETBITMASK) / FD_SETIDXMASK;\
 54		for (__idx = 0; __idx < __size; __idx++)		\
 55			__set->fds[__idx] = 0;				\
 56	} while (0)
 57
 58/*
 59 * int select(int nfds, fd_set *read_fds, fd_set *write_fds,
 60 *            fd_set *except_fds, struct timeval *timeout);
 61 */
 62
 63static __attribute__((unused))
 64int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
 65{
 66#if defined(__ARCH_WANT_SYS_OLD_SELECT) && !defined(__NR__newselect)
 67	struct sel_arg_struct {
 68		unsigned long n;
 69		fd_set *r, *w, *e;
 70		struct timeval *t;
 71	} arg = { .n = nfds, .r = rfds, .w = wfds, .e = efds, .t = timeout };
 72	return my_syscall1(__NR_select, &arg);
 73#elif defined(__NR__newselect)
 74	return my_syscall5(__NR__newselect, nfds, rfds, wfds, efds, timeout);
 75#elif defined(__NR_select)
 76	return my_syscall5(__NR_select, nfds, rfds, wfds, efds, timeout);
 77#elif defined(__NR_pselect6)
 78	struct timespec t;
 79
 80	if (timeout) {
 81		t.tv_sec  = timeout->tv_sec;
 82		t.tv_nsec = timeout->tv_usec * 1000;
 83	}
 84	return my_syscall6(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
 85#else
 86	struct __kernel_timespec t;
 87
 88	if (timeout) {
 89		t.tv_sec  = timeout->tv_sec;
 90		t.tv_nsec = timeout->tv_usec * 1000;
 91	}
 92	return my_syscall6(__NR_pselect6_time64, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
 93#endif
 94}
 95
 96static __attribute__((unused))
 97int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
 98{
 99	return __sysret(sys_select(nfds, rfds, wfds, efds, timeout));
100}
101
102
103#endif /* _NOLIBC_SYS_SELECT_H */