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93 lines
2.7 KiB
C
93 lines
2.7 KiB
C
/* POSIX compatible signal blocking for threads.
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Copyright (C) 2011-2021 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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/* Specification. */
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#include <signal.h>
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#include <errno.h>
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#include <stddef.h>
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#if PTHREAD_SIGMASK_INEFFECTIVE
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# include <string.h>
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#endif
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#if PTHREAD_SIGMASK_UNBLOCK_BUG
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# include <unistd.h>
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#endif
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int
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pthread_sigmask (int how, const sigset_t *new_mask, sigset_t *old_mask)
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#undef pthread_sigmask
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{
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#if HAVE_PTHREAD_SIGMASK
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int ret;
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# if PTHREAD_SIGMASK_INEFFECTIVE
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sigset_t omask, omask_copy;
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sigset_t *old_mask_ptr = &omask;
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sigemptyset (&omask);
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/* Add a signal unlikely to be blocked, so that OMASK_COPY
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is unlikely to match the actual mask. */
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sigaddset (&omask, SIGILL);
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memcpy (&omask_copy, &omask, sizeof omask);
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# else
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sigset_t *old_mask_ptr = old_mask;
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# endif
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ret = pthread_sigmask (how, new_mask, old_mask_ptr);
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# if PTHREAD_SIGMASK_INEFFECTIVE
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if (ret == 0)
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{
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/* Detect whether pthread_sigmask is currently ineffective.
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Don't cache the information: libpthread.so could be dynamically
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loaded after the program started and after pthread_sigmask was
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called for the first time. */
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if (memcmp (&omask_copy, &omask, sizeof omask) == 0
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&& pthread_sigmask (1729, &omask_copy, NULL) == 0)
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{
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/* pthread_sigmask is currently ineffective. The program is not
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linked to -lpthread. So use sigprocmask instead. */
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return (sigprocmask (how, new_mask, old_mask) < 0 ? errno : 0);
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}
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if (old_mask)
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memcpy (old_mask, &omask, sizeof omask);
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}
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# endif
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# if PTHREAD_SIGMASK_FAILS_WITH_ERRNO
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if (ret == -1)
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return errno;
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# endif
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# if PTHREAD_SIGMASK_UNBLOCK_BUG
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if (ret == 0
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&& new_mask != NULL
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&& (how == SIG_UNBLOCK || how == SIG_SETMASK))
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{
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/* Give the OS the opportunity to raise signals that were pending before
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the pthread_sigmask call and have now been unblocked. */
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usleep (1);
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}
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# endif
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return ret;
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#else
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int ret = sigprocmask (how, new_mask, old_mask);
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return (ret < 0 ? errno : 0);
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#endif
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}
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