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79 lines
2.7 KiB
C
79 lines
2.7 KiB
C
/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
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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 <signal.h>
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#include <stddef.h> /* For NULL. */
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#include <sys/time.h>
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#include <sys/select.h>
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#include <sysdep-cancel.h>
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/* Check the first NFDS descriptors each in READFDS (if not NULL) for read
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readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
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(if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out
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after waiting the interval specified therein. Additionally set the sigmask
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SIGMASK for this call. Returns the number of ready descriptors, or -1 for
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errors. */
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int
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__pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
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const struct timespec *timeout, const sigset_t *sigmask)
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{
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struct timeval tval;
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int retval;
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sigset_t savemask;
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/* Change nanosecond number to microseconds. This might mean losing
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precision and therefore the `pselect` should be available. But
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for now it is hardly found. */
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if (timeout != NULL)
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{
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/* Catch bugs which would be hidden by the TIMESPEC_TO_TIMEVAL
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computations. The division by 1000 truncates values. */
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if (__glibc_unlikely (timeout->tv_nsec < 0))
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{
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__set_errno (EINVAL);
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return -1;
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}
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TIMESPEC_TO_TIMEVAL (&tval, timeout);
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}
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/* The setting and restoring of the signal mask and the select call
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should be an atomic operation. This can't be done without kernel
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help. */
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if (sigmask != NULL)
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__sigprocmask (SIG_SETMASK, sigmask, &savemask);
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/* Note the pselect() is a cancellation point. But since we call
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select() which itself is a cancellation point we do not have
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to do anything here. */
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retval = __select (nfds, readfds, writefds, exceptfds,
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timeout != NULL ? &tval : NULL);
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if (sigmask != NULL)
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__sigprocmask (SIG_SETMASK, &savemask, NULL);
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return retval;
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}
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#ifndef __pselect
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weak_alias (__pselect, pselect)
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/* __select handles cancellation. */
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LIBC_CANCEL_HANDLED ();
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#endif
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