[pulseaudio-discuss] [PATCH v3] pipe-source: optional suspend source when no writers connected to fifo
Georg Chini
georg at chini.tk
Tue Feb 13 15:37:58 UTC 2018
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. ..."
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.
> + 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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