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109 lines
2.9 KiB
C
109 lines
2.9 KiB
C
/* Implementation of sigwait function from POSIX.1c.
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Copyright (C) 1996-2019 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 <sysdep-cancel.h>
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/* This is our dummy signal handler we use here. */
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static void ignore_signal (int sig);
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/* Place where to remember which signal we got. Please note that this
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implementation cannot be used for the threaded libc. The
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libpthread must provide an own version. */
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static int was_sig;
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static int
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do_sigwait (const sigset_t *set, int *sig)
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{
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sigset_t tmp_mask;
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struct sigaction saved[NSIG];
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struct sigaction action;
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int save_errno;
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int this;
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/* Prepare set. */
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__sigfillset (&tmp_mask);
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/* Unblock all signals in the SET and register our nice handler. */
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action.sa_handler = ignore_signal;
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action.sa_flags = 0;
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__sigfillset (&action.sa_mask); /* Block all signals for handler. */
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/* Make sure we recognize error conditions by setting WAS_SIG to a
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value which does not describe a legal signal number. */
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was_sig = -1;
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for (this = 1; this < NSIG; ++this)
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if (__sigismember (set, this))
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{
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/* Unblock this signal. */
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__sigdelset (&tmp_mask, this);
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/* Register temporary action handler. */
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if (__sigaction (this, &action, &saved[this]) != 0)
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goto restore_handler;
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}
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/* Now we can wait for signals. */
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__sigsuspend (&tmp_mask);
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restore_handler:
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save_errno = errno;
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while (--this >= 1)
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if (__sigismember (set, this))
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/* We ignore errors here since we must restore all handlers. */
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__sigaction (this, &saved[this], NULL);
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__set_errno (save_errno);
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/* Store the result and return. */
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*sig = was_sig;
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return was_sig == -1 ? -1 : 0;
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}
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int
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__sigwait (const sigset_t *set, int *sig)
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{
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if (SINGLE_THREAD_P)
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return do_sigwait (set, sig);
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int oldtype = LIBC_CANCEL_ASYNC ();
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int result = do_sigwait (set, sig);
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LIBC_CANCEL_RESET (oldtype);
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return result;
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}
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libc_hidden_def (__sigwait)
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weak_alias (__sigwait, sigwait)
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static void
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ignore_signal (int sig)
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{
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/* Remember the signal. */
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was_sig = sig;
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}
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