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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/tools/include/nolibc/sys/select.h
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/* SPDX-License-Identifier: LGPL-2.1 OR MIT */

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#include "../nolibc.h"

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#ifndef _NOLIBC_SYS_SELECT_H

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#define _NOLIBC_SYS_SELECT_H

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#include <linux/time.h>

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#include <linux/unistd.h>

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/* commonly an fd_set represents 256 FDs */

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#ifndef FD_SETSIZE

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#define FD_SETSIZE     256

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#endif

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#define FD_SETIDXMASK (8 * sizeof(unsigned long))

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#define FD_SETBITMASK (8 * sizeof(unsigned long)-1)

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/* for select() */

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typedef struct {

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	unsigned long fds[(FD_SETSIZE + FD_SETBITMASK) / FD_SETIDXMASK];

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} fd_set;

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#define FD_CLR(fd, set) do {						\

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		fd_set *__set = (set);					\

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		int __fd = (fd);					\

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		if (__fd >= 0)						\

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			__set->fds[__fd / FD_SETIDXMASK] &=		\

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				~(1U << (__fd & FD_SETBITMASK));	\

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	} while (0)

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#define FD_SET(fd, set) do {						\

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		fd_set *__set = (set);					\

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		int __fd = (fd);					\

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		if (__fd >= 0)						\

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			__set->fds[__fd / FD_SETIDXMASK] |=		\

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				1 << (__fd & FD_SETBITMASK);		\

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	} while (0)

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#define FD_ISSET(fd, set) ({						\

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			fd_set *__set = (set);				\

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			int __fd = (fd);				\

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		int __r = 0;						\

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		if (__fd >= 0)						\

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			__r = !!(__set->fds[__fd / FD_SETIDXMASK] &	\

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1U << (__fd & FD_SETBITMASK));						\

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		__r;							\

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	})

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#define FD_ZERO(set) do {						\

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		fd_set *__set = (set);					\

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		int __idx;						\

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		int __size = (FD_SETSIZE+FD_SETBITMASK) / FD_SETIDXMASK;\

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		for (__idx = 0; __idx < __size; __idx++)		\

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			__set->fds[__idx] = 0;				\

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	} while (0)

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/*

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 * int select(int nfds, fd_set *read_fds, fd_set *write_fds,

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 *            fd_set *except_fds, struct timeval *timeout);

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 */

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static __attribute__((unused))

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int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)

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{

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#if defined(__ARCH_WANT_SYS_OLD_SELECT) && !defined(__NR__newselect)

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	struct sel_arg_struct {

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		unsigned long n;

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		fd_set *r, *w, *e;

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		struct timeval *t;

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	} arg = { .n = nfds, .r = rfds, .w = wfds, .e = efds, .t = timeout };

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	return my_syscall1(__NR_select, &arg);

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#elif defined(__NR__newselect)

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	return my_syscall5(__NR__newselect, nfds, rfds, wfds, efds, timeout);

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#elif defined(__NR_select)

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	return my_syscall5(__NR_select, nfds, rfds, wfds, efds, timeout);

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#elif defined(__NR_pselect6)

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	struct timespec t;

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	if (timeout) {

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		t.tv_sec  = timeout->tv_sec;

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		t.tv_nsec = timeout->tv_usec * 1000;

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	}

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	return my_syscall6(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);

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#else

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	struct __kernel_timespec t;

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	if (timeout) {

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		t.tv_sec  = timeout->tv_sec;

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		t.tv_nsec = timeout->tv_usec * 1000;

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	}

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	return my_syscall6(__NR_pselect6_time64, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);

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#endif

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}

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static __attribute__((unused))

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int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)

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{

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	return __sysret(sys_select(nfds, rfds, wfds, efds, timeout));

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}

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#endif /* _NOLIBC_SYS_SELECT_H */

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