[pulseaudio-discuss] [PATCH v3] pipe-source: optional suspend source when no writers connected to fifo
Raman Shishniou
rommer at ibuffed.com
Wed Feb 14 09:38:28 UTC 2018
On 02/13/2018 06:37 PM, Georg Chini wrote:
> On 11.02.2018 00:36, Raman Shyshniou wrote:
>> Add autosuspend=<bool> option. Enabling this option will make
>> pipe-source suspended when all writers closed fifo. Source will
>> be automatically unsuspended if any data will be written to pipe
>> and suspended again when last writer closed fifo.
> Can you add a sentence about the motivation to the commit
> message? Something like "Currently the pipe-source will remain
> running even if no writer is connected and therefore no data is
> produced. This patch adds the autosuspend=<bool> option to
> prevent this. ..."
>
Ok.
> Otherwise only two small comments below.
>> ---
>> src/modules/module-pipe-source.c | 136 +++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 129 insertions(+), 7 deletions(-)
>>
>> diff --git a/src/modules/module-pipe-source.c b/src/modules/module-pipe-source.c
>> index f8284c1..af7badc 100644
>> --- a/src/modules/module-pipe-source.c
>> +++ b/src/modules/module-pipe-source.c
>> @@ -57,11 +57,24 @@ PA_MODULE_USAGE(
>> "format=<sample format> "
>> "rate=<sample rate> "
>> "channels=<number of channels> "
>> - "channel_map=<channel map>");
>> + "channel_map=<channel map> "
>> + "autosuspend=<boolean>");
>> #define DEFAULT_FILE_NAME "/tmp/music.input"
>> #define DEFAULT_SOURCE_NAME "fifo_input"
>> +struct pipe_source_msg {
>> + pa_msgobject parent;
>> +};
>> +
>> +typedef struct pipe_source_msg pipe_source_msg;
>> +PA_DEFINE_PRIVATE_CLASS(pipe_source_msg, pa_msgobject);
>> +
>> +enum {
>> + PIPE_SOURCE_SUSPEND,
>> + PIPE_SOURCE_RESUME,
>> +};
>> +
>> struct userdata {
>> pa_core *core;
>> pa_module *module;
>> @@ -71,7 +84,10 @@ struct userdata {
>> pa_thread_mq thread_mq;
>> pa_rtpoll *rtpoll;
>> + pipe_source_msg *msg;
>> +
>> char *filename;
>> + int corkfd;
>> int fd;
>> pa_memchunk memchunk;
>> @@ -87,9 +103,41 @@ static const char* const valid_modargs[] = {
>> "rate",
>> "channels",
>> "channel_map",
>> + "autosuspend",
>> NULL
>> };
>> +/* Called from main context */
>> +static int pipe_source_process_msg(
>> + pa_msgobject *o,
>> + int code,
>> + void *data,
>> + int64_t offset,
>> + pa_memchunk *chunk) {
>> +
>> + struct userdata *u = (struct userdata *) data;
>> +
>> + pa_assert(u);
>> +
>> + switch (code) {
>> + case PIPE_SOURCE_SUSPEND:
>> + pa_log_debug("Suspending source %s because no writers left", u->source->name);
>> + pa_source_suspend(u->source, true, PA_SUSPEND_APPLICATION);
>> + break;
>> +
>> + case PIPE_SOURCE_RESUME:
>> + pa_log_debug("Resuming source %s because writer connected", u->source->name);
>> + pa_source_suspend(u->source, false, PA_SUSPEND_APPLICATION);
>> + break;
>> +
>> + default:
>> + pa_assert_not_reached();
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/* Called from thread context */
>> static int source_process_msg(
>> pa_msgobject *o,
>> int code,
>> @@ -135,8 +183,15 @@ static void thread_func(void *userdata) {
>> pollfd = pa_rtpoll_item_get_pollfd(u->rtpoll_item, NULL);
>> + /* Writer connected */
>> + if (u->corkfd >= 0 && pollfd->revents & POLLIN) {
>> + pa_asyncmsgq_post(pa_thread_mq_get()->outq, PA_MSGOBJECT(u->msg), PIPE_SOURCE_RESUME, u, 0, NULL, NULL);
>> + pa_assert_se(pa_close(u->corkfd) == 0);
>> + u->corkfd = -1;
>> + }
>> +
>> /* Try to read some data and pass it on to the source driver */
>> - if (u->source->thread_info.state == PA_SOURCE_RUNNING && pollfd->revents) {
>> + if (u->source->thread_info.state == PA_SOURCE_RUNNING && pollfd->revents & POLLIN) {
>> ssize_t l;
>> void *p;
>> @@ -151,8 +206,6 @@ static void thread_func(void *userdata) {
>> l = pa_read(u->fd, (uint8_t*) p + u->memchunk.index, pa_memblock_get_length(u->memchunk.memblock) - u->memchunk.index, &read_type);
>> pa_memblock_release(u->memchunk.memblock);
>> - pa_assert(l != 0); /* EOF cannot happen, since we opened the fifo for both reading and writing */
>> -
>> if (l < 0) {
>> if (errno == EINTR)
>> @@ -162,6 +215,11 @@ static void thread_func(void *userdata) {
>> goto fail;
>> }
>> + } else if (l == 0) {
>> +
>> + /* Nothing to read */
>> + pollfd->revents = 0;
>> +
>> } else {
>> u->memchunk.length = (size_t) l;
>> @@ -178,7 +236,7 @@ static void thread_func(void *userdata) {
>> }
>> /* Hmm, nothing to do. Let's sleep */
>> - pollfd->events = (short) (u->source->thread_info.state == PA_SOURCE_RUNNING ? POLLIN : 0);
>> + pollfd->events = (short) ((u->source->thread_info.state == PA_SOURCE_RUNNING || u->corkfd >= 0) ? POLLIN : 0);
>> if ((ret = pa_rtpoll_run(u->rtpoll)) < 0)
>> goto fail;
>> @@ -188,6 +246,29 @@ static void thread_func(void *userdata) {
>> pollfd = pa_rtpoll_item_get_pollfd(u->rtpoll_item, NULL);
>> + /* Last writer disconnected but data may still be in the buffer */
>> + if (pollfd->revents & POLLHUP) {
>> + int l = 0;
>> +
>> +#ifdef FIONREAD
>> + ioctl(u->fd, FIONREAD, &l);
>> +#endif
>> +
>> + if (!l && u->corkfd < 0) {
>> + /* Suspend source */
>> + pa_asyncmsgq_post(pa_thread_mq_get()->outq, PA_MSGOBJECT(u->msg), PIPE_SOURCE_SUSPEND, u, 0, NULL, NULL);
>> +
>> + /* Open fifo for writing to stop POLLHUP spam */
>> + if ((u->corkfd = pa_open_cloexec(u->filename, O_WRONLY, 0)) < 0) {
>> + pa_log("open('%s'): %s", u->filename, pa_cstrerror(errno));
>> + goto fail;
>> + }
>> + }
>> +
>> + /* Ignore POOLHUP anyway */
>
> typo above.
>
>> + pollfd->revents &= ~POLLHUP;
>> + }
>> +
>> if (pollfd->revents & ~POLLIN) {
>> pa_log("FIFO shutdown.");
>> goto fail;
>> @@ -212,6 +293,7 @@ int pa__init(pa_module *m) {
>> pa_modargs *ma;
>> struct pollfd *pollfd;
>> pa_source_new_data data;
>> + bool autosuspend = false;
>> pa_assert(m);
>> @@ -238,17 +320,51 @@ int pa__init(pa_module *m) {
>> goto fail;
>> }
>> + u->corkfd = -1;
>> +
>> + if (!(u->msg = pa_msgobject_new(pipe_source_msg)))
>> + goto fail;
>> +
>> + u->msg->parent.process_msg = pipe_source_process_msg;
>> +
>> u->filename = pa_runtime_path(pa_modargs_get_value(ma, "file", DEFAULT_FILE_NAME));
>> if (mkfifo(u->filename, 0666) < 0) {
>> pa_log("mkfifo('%s'): %s", u->filename, pa_cstrerror(errno));
>> goto fail;
>> }
>> - if ((u->fd = pa_open_cloexec(u->filename, O_RDWR, 0)) < 0) {
>> - pa_log("open('%s'): %s", u->filename, pa_cstrerror(errno));
>> +
>> + if (pa_modargs_get_value_boolean(ma, "autosuspend", &autosuspend) < 0) {
>> + pa_log("Failed to parse autosuspend= argument.");
>> goto fail;
>> }
>> + if (autosuspend) {
>> + int rwfd;
>> +
>> + /* Open fifo for read and write first, so the next open for read-only
>> + will be succeded immediately */
>> + if ((rwfd = pa_open_cloexec(u->filename, O_RDWR, 0)) < 0) {
>> + pa_log("open('%s'): %s", u->filename, pa_cstrerror(errno));
>> + goto fail;
>> + }
>> +
>> + if ((u->fd = pa_open_cloexec(u->filename, O_RDONLY, 0)) < 0) {
>> + pa_log("open('%s'): %s", u->filename, pa_cstrerror(errno));
>> + pa_assert_se(pa_close(rwfd) == 0);
>> + goto fail;
>> + }
>> +
>
> You could #ifdef O_NONBLOCK and only open the FIFO for RDWR if the
> option does not exist.
>
Agreed. I thought about SOCK_NONBLOCK which is supported since linux 2.6.27,
but O_NONBLOCK for open(2) was always supported.
>> + pa_assert_se(pa_close(rwfd) == 0);
>> +
>> + } else {
>> + /* Open fifo for read and write, so there will be at least one writer */
>> + if ((u->fd = pa_open_cloexec(u->filename, O_RDWR, 0)) < 0) {
>> + pa_log("open('%s'): %s", u->filename, pa_cstrerror(errno));
>> + goto fail;
>> + }
>> + }
>> +
>> pa_make_fd_nonblock(u->fd);
>> if (fstat(u->fd, &st) < 0) {
>> @@ -360,6 +476,12 @@ void pa__done(pa_module *m) {
>> pa_xfree(u->filename);
>> }
>> + if (u->msg)
>> + pa_xfree(u->msg);
>> +
>> + if (u->corkfd >= 0)
>> + pa_assert_se(pa_close(u->corkfd) == 0);
>> +
>> if (u->fd >= 0)
>> pa_assert_se(pa_close(u->fd) == 0);
>>
>
>
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