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code.delx.au - pulseaudio/blob - src/pulsecore/fdsem.c
2 This file is part of PulseAudio.
4 Copyright 2006 Lennart Poettering
6 PulseAudio is free software; you can redistribute it and/or modify
7 it under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 2.1 of the
9 License, or (at your option) any later version.
11 PulseAudio is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with PulseAudio; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
26 #ifdef HAVE_SYS_SYSCALL_H
27 #include <sys/syscall.h>
33 #include <pulsecore/atomic.h>
34 #include <pulsecore/log.h>
35 #include <pulsecore/thread.h>
36 #include <pulsecore/macro.h>
37 #include <pulsecore/core-util.h>
38 #include <pulse/xmalloc.h>
41 #include <pulsecore/pipe.h>
46 #if !defined(__NR_eventfd) && defined(__i386__)
47 #define __NR_eventfd 323
50 #if !defined(__NR_eventfd) && defined(__x86_64__)
51 #define __NR_eventfd 284
54 #if !defined(__NR_eventfd) && defined(__arm__)
55 #define __NR_eventfd (__NR_SYSCALL_BASE+351)
58 #if !defined(SYS_eventfd) && defined(__NR_eventfd)
59 #define SYS_eventfd __NR_eventfd
65 static inline long eventfd(unsigned count
) {
66 return syscall(SYS_eventfd
, count
);
83 pa_fdsem
*pa_fdsem_new(void) {
86 f
= pa_xmalloc(PA_ALIGN(sizeof(pa_fdsem
)) + PA_ALIGN(sizeof(pa_fdsem_data
)));
89 if ((f
->efd
= eventfd(0)) >= 0) {
90 pa_make_fd_cloexec(f
->efd
);
91 f
->fds
[0] = f
->fds
[1] = -1;
95 if (pipe(f
->fds
) < 0) {
100 pa_make_fd_cloexec(f
->fds
[0]);
101 pa_make_fd_cloexec(f
->fds
[1]);
104 f
->data
= (pa_fdsem_data
*) ((uint8_t*) f
+ PA_ALIGN(sizeof(pa_fdsem
)));
106 pa_atomic_store(&f
->data
->waiting
, 0);
107 pa_atomic_store(&f
->data
->signalled
, 0);
108 pa_atomic_store(&f
->data
->in_pipe
, 0);
113 pa_fdsem
*pa_fdsem_open_shm(pa_fdsem_data
*data
, int event_fd
) {
117 pa_assert(event_fd
>= 0);
120 f
= pa_xnew(pa_fdsem
, 1);
123 pa_make_fd_cloexec(f
->efd
);
124 f
->fds
[0] = f
->fds
[1] = -1;
131 pa_fdsem
*pa_fdsem_new_shm(pa_fdsem_data
*data
, int* event_fd
) {
139 f
= pa_xnew(pa_fdsem
, 1);
141 if ((f
->efd
= eventfd(0)) < 0) {
146 pa_make_fd_cloexec(f
->efd
);
147 f
->fds
[0] = f
->fds
[1] = -1;
150 pa_atomic_store(&f
->data
->waiting
, 0);
151 pa_atomic_store(&f
->data
->signalled
, 0);
152 pa_atomic_store(&f
->data
->in_pipe
, 0);
159 void pa_fdsem_free(pa_fdsem
*f
) {
166 pa_close_pipe(f
->fds
);
171 static void flush(pa_fdsem
*f
) {
175 if (pa_atomic_load(&f
->data
->in_pipe
) <= 0)
185 if ((r
= read(f
->efd
, &u
, sizeof(u
))) != sizeof(u
)) {
186 pa_assert(r
< 0 && errno
== EINTR
);
193 if ((r
= read(f
->fds
[0], &x
, sizeof(x
))) <= 0) {
194 pa_assert(r
< 0 && errno
== EINTR
);
198 } while (pa_atomic_sub(&f
->data
->in_pipe
, r
) > r
);
201 void pa_fdsem_post(pa_fdsem
*f
) {
204 if (pa_atomic_cmpxchg(&f
->data
->signalled
, 0, 1)) {
206 if (pa_atomic_load(&f
->data
->waiting
)) {
210 pa_atomic_inc(&f
->data
->in_pipe
);
218 if ((r
= write(f
->efd
, &u
, sizeof(u
))) != sizeof(u
)) {
219 pa_assert(r
< 0 && errno
== EINTR
);
225 if ((r
= write(f
->fds
[1], &x
, 1)) != 1) {
226 pa_assert(r
< 0 && errno
== EINTR
);
236 void pa_fdsem_wait(pa_fdsem
*f
) {
241 if (pa_atomic_cmpxchg(&f
->data
->signalled
, 1, 0))
244 pa_atomic_inc(&f
->data
->waiting
);
246 while (!pa_atomic_cmpxchg(&f
->data
->signalled
, 1, 0)) {
254 if ((r
= read(f
->efd
, &u
, sizeof(u
))) != sizeof(u
)) {
255 pa_assert(r
< 0 && errno
== EINTR
);
263 if ((r
= read(f
->fds
[0], &x
, sizeof(x
))) <= 0) {
264 pa_assert(r
< 0 && errno
== EINTR
);
268 pa_atomic_sub(&f
->data
->in_pipe
, r
);
271 pa_assert_se(pa_atomic_dec(&f
->data
->waiting
) >= 1);
274 int pa_fdsem_try(pa_fdsem
*f
) {
279 if (pa_atomic_cmpxchg(&f
->data
->signalled
, 1, 0))
285 int pa_fdsem_get(pa_fdsem
*f
) {
296 int pa_fdsem_before_poll(pa_fdsem
*f
) {
301 if (pa_atomic_cmpxchg(&f
->data
->signalled
, 1, 0))
304 pa_atomic_inc(&f
->data
->waiting
);
306 if (pa_atomic_cmpxchg(&f
->data
->signalled
, 1, 0)) {
307 pa_assert_se(pa_atomic_dec(&f
->data
->waiting
) >= 1);
313 int pa_fdsem_after_poll(pa_fdsem
*f
) {
316 pa_assert_se(pa_atomic_dec(&f
->data
->waiting
) >= 1);
320 if (pa_atomic_cmpxchg(&f
->data
->signalled
, 1, 0))