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105 lines
2.6 KiB
C
105 lines
2.6 KiB
C
/* Poll system call, with emulation if it is not available.
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Copyright (C) 1997,1998,1999,2000,2001,2002,2006
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Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <sys/poll.h>
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#include <sysdep-cancel.h>
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#include <sys/syscall.h>
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#include <bp-checks.h>
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#include <kernel-features.h>
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#if defined __NR_poll || __ASSUME_POLL_SYSCALL > 0
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# if __ASSUME_POLL_SYSCALL == 0
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static int __emulate_poll (struct pollfd *fds, nfds_t nfds,
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int timeout) internal_function;
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# endif
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# if __ASSUME_POLL_SYSCALL == 0
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/* For loser kernels. */
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static int
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loser_poll (struct pollfd *fds, nfds_t nfds, int timeout)
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{
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static int must_emulate;
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if (!must_emulate)
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{
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int errno_saved = errno;
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int retval = INLINE_SYSCALL (poll, 3, CHECK_N (fds, nfds), nfds,
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timeout);
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if (retval >= 0 || errno != ENOSYS)
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return retval;
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__set_errno (errno_saved);
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must_emulate = 1;
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}
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return __emulate_poll (fds, nfds, timeout);
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}
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# endif
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/* The real implementation. */
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int
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__poll (fds, nfds, timeout)
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struct pollfd *fds;
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nfds_t nfds;
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int timeout;
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{
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# if __ASSUME_POLL_SYSCALL == 0
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if (SINGLE_THREAD_P)
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return loser_poll (CHECK_N (fds, nfds), nfds, timeout);
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int oldtype = LIBC_CANCEL_ASYNC ();
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int result = loser_poll (CHECK_N (fds, nfds), nfds, timeout);
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LIBC_CANCEL_RESET (oldtype);
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return result;
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# else
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if (SINGLE_THREAD_P)
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return INLINE_SYSCALL (poll, 3, CHECK_N (fds, nfds), nfds, timeout);
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int oldtype = LIBC_CANCEL_ASYNC ();
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int result = INLINE_SYSCALL (poll, 3, CHECK_N (fds, nfds), nfds, timeout);
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LIBC_CANCEL_RESET (oldtype);
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return result;
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# endif
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}
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libc_hidden_def (__poll)
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weak_alias (__poll, poll)
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strong_alias (__poll, __libc_poll)
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/* Get the emulation code. */
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# define __poll(fds, nfds, timeout) \
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static internal_function __emulate_poll (fds, nfds, timeout)
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#endif
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#if __ASSUME_POLL_SYSCALL == 0
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# include <sysdeps/unix/bsd/poll.c>
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#endif
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