mirror of
https://gitlab.freedesktop.org/pulseaudio/pulseaudio.git
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323 lines
7 KiB
C
323 lines
7 KiB
C
/***
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This file is part of PulseAudio.
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Copyright 2006 Lennart Poettering
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PulseAudio is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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PulseAudio is distributed in the hope that it will be useful, but
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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 PulseAudio; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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USA.
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***/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#ifdef HAVE_SYS_SYSCALL_H
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#include <sys/syscall.h>
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#endif
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#include <unistd.h>
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#include <errno.h>
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#include <pulsecore/atomic.h>
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#include <pulsecore/log.h>
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#include <pulsecore/macro.h>
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#include <pulsecore/core-util.h>
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#include <pulsecore/core-error.h>
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#include <pulse/xmalloc.h>
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#ifndef HAVE_PIPE
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#include <pulsecore/pipe.h>
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#endif
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#ifdef HAVE_SYS_EVENTFD_H
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#include <sys/eventfd.h>
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#endif
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#include "fdsem.h"
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struct pa_fdsem {
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int fds[2];
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#ifdef HAVE_SYS_EVENTFD_H
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int efd;
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#endif
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pa_fdsem_data *data;
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};
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pa_fdsem *pa_fdsem_new(void) {
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pa_fdsem *f;
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f = pa_xmalloc(PA_ALIGN(sizeof(pa_fdsem)) + PA_ALIGN(sizeof(pa_fdsem_data)));
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#ifdef HAVE_SYS_EVENTFD_H
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if ((f->efd = eventfd(0, EFD_CLOEXEC)) >= 0)
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f->fds[0] = f->fds[1] = -1;
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else
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#endif
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{
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if (pa_pipe_cloexec(f->fds) < 0) {
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pa_xfree(f);
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return NULL;
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}
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}
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f->data = (pa_fdsem_data*) ((uint8_t*) f + PA_ALIGN(sizeof(pa_fdsem)));
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pa_atomic_store(&f->data->waiting, 0);
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pa_atomic_store(&f->data->signalled, 0);
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pa_atomic_store(&f->data->in_pipe, 0);
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return f;
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}
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pa_fdsem *pa_fdsem_open_shm(pa_fdsem_data *data, int event_fd) {
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pa_fdsem *f = NULL;
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pa_assert(data);
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pa_assert(event_fd >= 0);
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#ifdef HAVE_SYS_EVENTFD_H
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f = pa_xnew(pa_fdsem, 1);
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f->efd = event_fd;
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pa_make_fd_cloexec(f->efd);
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f->fds[0] = f->fds[1] = -1;
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f->data = data;
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#endif
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return f;
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}
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pa_fdsem *pa_fdsem_new_shm(pa_fdsem_data *data, int* event_fd) {
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pa_fdsem *f = NULL;
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pa_assert(data);
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pa_assert(event_fd);
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#ifdef HAVE_SYS_EVENTFD_H
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f = pa_xnew(pa_fdsem, 1);
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if ((f->efd = eventfd(0, EFD_CLOEXEC)) < 0) {
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pa_xfree(f);
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return NULL;
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}
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f->fds[0] = f->fds[1] = -1;
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f->data = data;
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pa_atomic_store(&f->data->waiting, 0);
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pa_atomic_store(&f->data->signalled, 0);
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pa_atomic_store(&f->data->in_pipe, 0);
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#endif
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return f;
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}
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void pa_fdsem_free(pa_fdsem *f) {
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pa_assert(f);
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#ifdef HAVE_SYS_EVENTFD_H
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if (f->efd >= 0)
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pa_close(f->efd);
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#endif
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pa_close_pipe(f->fds);
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pa_xfree(f);
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}
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static void flush(pa_fdsem *f) {
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ssize_t r;
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pa_assert(f);
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if (pa_atomic_load(&f->data->in_pipe) <= 0)
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return;
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do {
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char x[10];
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#ifdef HAVE_SYS_EVENTFD_H
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if (f->efd >= 0) {
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uint64_t u;
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if ((r = pa_read(f->efd, &u, sizeof(u), NULL)) != sizeof(u)) {
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if (r >= 0 || errno != EINTR) {
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pa_log_error("Invalid read from eventfd: %s", r < 0 ? pa_cstrerror(errno) : "EOF");
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pa_assert_not_reached();
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}
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continue;
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}
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r = (ssize_t) u;
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} else
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#endif
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if ((r = pa_read(f->fds[0], &x, sizeof(x), NULL)) <= 0) {
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if (r >= 0 || errno != EINTR) {
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pa_log_error("Invalid read from pipe: %s", r < 0 ? pa_cstrerror(errno) : "EOF");
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pa_assert_not_reached();
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}
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continue;
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}
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} while (pa_atomic_sub(&f->data->in_pipe, (int) r) > (int) r);
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}
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void pa_fdsem_post(pa_fdsem *f) {
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pa_assert(f);
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if (pa_atomic_cmpxchg(&f->data->signalled, 0, 1)) {
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if (pa_atomic_load(&f->data->waiting)) {
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ssize_t r;
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char x = 'x';
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pa_atomic_inc(&f->data->in_pipe);
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for (;;) {
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#ifdef HAVE_SYS_EVENTFD_H
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if (f->efd >= 0) {
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uint64_t u = 1;
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if ((r = pa_write(f->efd, &u, sizeof(u), NULL)) != sizeof(u)) {
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if (r >= 0 || errno != EINTR) {
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pa_log_error("Invalid write to eventfd: %s", r < 0 ? pa_cstrerror(errno) : "EOF");
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pa_assert_not_reached();
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}
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continue;
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}
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} else
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#endif
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if ((r = pa_write(f->fds[1], &x, 1, NULL)) != 1) {
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if (r >= 0 || errno != EINTR) {
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pa_log_error("Invalid write to pipe: %s", r < 0 ? pa_cstrerror(errno) : "EOF");
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pa_assert_not_reached();
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}
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continue;
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}
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break;
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}
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}
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}
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}
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void pa_fdsem_wait(pa_fdsem *f) {
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pa_assert(f);
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flush(f);
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if (pa_atomic_cmpxchg(&f->data->signalled, 1, 0))
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return;
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pa_atomic_inc(&f->data->waiting);
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while (!pa_atomic_cmpxchg(&f->data->signalled, 1, 0)) {
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char x[10];
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ssize_t r;
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#ifdef HAVE_SYS_EVENTFD_H
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if (f->efd >= 0) {
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uint64_t u;
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if ((r = pa_read(f->efd, &u, sizeof(u), NULL)) != sizeof(u)) {
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if (r >= 0 || errno != EINTR) {
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pa_log_error("Invalid read from eventfd: %s", r < 0 ? pa_cstrerror(errno) : "EOF");
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pa_assert_not_reached();
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}
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continue;
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}
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r = (ssize_t) u;
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} else
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#endif
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if ((r = pa_read(f->fds[0], &x, sizeof(x), NULL)) <= 0) {
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if (r >= 0 || errno != EINTR) {
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pa_log_error("Invalid read from pipe: %s", r < 0 ? pa_cstrerror(errno) : "EOF");
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pa_assert_not_reached();
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}
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continue;
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}
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pa_atomic_sub(&f->data->in_pipe, (int) r);
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}
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pa_assert_se(pa_atomic_dec(&f->data->waiting) >= 1);
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}
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int pa_fdsem_try(pa_fdsem *f) {
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pa_assert(f);
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flush(f);
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if (pa_atomic_cmpxchg(&f->data->signalled, 1, 0))
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return 1;
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return 0;
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}
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int pa_fdsem_get(pa_fdsem *f) {
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pa_assert(f);
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#ifdef HAVE_SYS_EVENTFD_H
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if (f->efd >= 0)
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return f->efd;
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#endif
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return f->fds[0];
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}
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int pa_fdsem_before_poll(pa_fdsem *f) {
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pa_assert(f);
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flush(f);
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if (pa_atomic_cmpxchg(&f->data->signalled, 1, 0))
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return -1;
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pa_atomic_inc(&f->data->waiting);
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if (pa_atomic_cmpxchg(&f->data->signalled, 1, 0)) {
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pa_assert_se(pa_atomic_dec(&f->data->waiting) >= 1);
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return -1;
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}
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return 0;
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}
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int pa_fdsem_after_poll(pa_fdsem *f) {
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pa_assert(f);
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pa_assert_se(pa_atomic_dec(&f->data->waiting) >= 1);
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flush(f);
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if (pa_atomic_cmpxchg(&f->data->signalled, 1, 0))
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return 1;
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return 0;
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}
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