[pulseaudio-discuss] [PATCH] tunnel-source-new: counterpart to module-tunnel-sink-new

Tanu Kaskinen tanu.kaskinen at linux.intel.com
Sat Sep 7 10:49:15 PDT 2013


On Thu, 2013-08-29 at 14:26 +0200, Alexander Couzens wrote:
> The old tunnel module duplicates functionality that is in libpulse,
> due to implementing the native protocol, and the protocol code in
> the old tunnel module tends to get broken every now and then, because
> people forget to update the tunnel module protocol implementation
> when changing the native protocol. module-tunnel-source-new avoids this
> problem by using libpulse to communicate with the remote server.
> 
> Signed-off-by: Alexander Couzens <lynxis at fe80.eu>
> ---
>  src/Makefile.am                        |   6 +
>  src/modules/module-tunnel-source-new.c | 526 +++++++++++++++++++++++++++++++++
>  2 files changed, 532 insertions(+)
>  create mode 100644 src/modules/module-tunnel-source-new.c
> 
> diff --git a/src/Makefile.am b/src/Makefile.am
> index 27477e9..9d96a9b 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -1098,6 +1098,7 @@ modlibexec_LTLIBRARIES += \
>  		module-remap-source.la \
>  		module-ladspa-sink.la \
>  		module-tunnel-sink-new.la \
> +		module-tunnel-source-new.la \
>  		module-tunnel-sink.la \
>  		module-tunnel-source.la \
>  		module-position-event-sounds.la \
> @@ -1370,6 +1371,7 @@ SYMDEF_FILES = \
>  		module-equalizer-sink-symdef.h \
>  		module-match-symdef.h \
>  		module-tunnel-sink-new-symdef.h \
> +		module-tunnel-source-new-symdef.h \
>  		module-tunnel-sink-symdef.h \
>  		module-tunnel-source-symdef.h \
>  		module-null-sink-symdef.h \
> @@ -1644,6 +1646,10 @@ module_tunnel_sink_new_la_SOURCES = modules/module-tunnel-sink-new.c
>  module_tunnel_sink_new_la_LDFLAGS = $(MODULE_LDFLAGS)
>  module_tunnel_sink_new_la_LIBADD = $(MODULE_LIBADD)
>  
> +module_tunnel_source_new_la_SOURCES = modules/module-tunnel-source-new.c
> +module_tunnel_source_new_la_LDFLAGS = $(MODULE_LDFLAGS)
> +module_tunnel_source_new_la_LIBADD = $(MODULE_LIBADD)
> +
>  module_tunnel_sink_la_SOURCES = modules/module-tunnel.c
>  module_tunnel_sink_la_CFLAGS = -DTUNNEL_SINK=1 $(AM_CFLAGS)
>  module_tunnel_sink_la_LDFLAGS = $(MODULE_LDFLAGS)
> diff --git a/src/modules/module-tunnel-source-new.c b/src/modules/module-tunnel-source-new.c
> new file mode 100644
> index 0000000..c59c4d3
> --- /dev/null
> +++ b/src/modules/module-tunnel-source-new.c
> @@ -0,0 +1,526 @@
> +/***
> +    This file is part of PulseAudio.
> +
> +    Copyright 2013 Alexander Couzens
> +
> +    PulseAudio is free software; you can redistribute it and/or modify
> +    it under the terms of the GNU Lesser General Public License as published
> +    by the Free Software Foundation; either version 2.1 of the License,
> +    or (at your option) any later version.
> +
> +    PulseAudio is distributed in the hope that it will be useful, but
> +    WITHOUT ANY WARRANTY; without even the implied warranty of
> +    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> +    General Public License for more details.
> +
> +    You should have received a copy of the GNU Lesser General Public License
> +    along with PulseAudio; if not, write to the Free Software
> +    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
> +    USA.
> +***/
> +
> +#ifdef HAVE_CONFIG_H
> +#include <config.h>
> +#endif
> +
> +#include <pulse/context.h>
> +#include <pulse/timeval.h>
> +#include <pulse/xmalloc.h>
> +#include <pulse/stream.h>
> +#include <pulse/mainloop.h>
> +#include <pulse/introspect.h>
> +#include <pulse/error.h>
> +
> +#include <pulsecore/core.h>
> +#include <pulsecore/core-util.h>
> +#include <pulsecore/i18n.h>
> +#include <pulsecore/source.h>
> +#include <pulsecore/modargs.h>
> +#include <pulsecore/log.h>
> +#include <pulsecore/thread.h>
> +#include <pulsecore/thread-mq.h>
> +#include <pulsecore/poll.h>
> +#include <pulsecore/proplist-util.h>
> +
> +#include "module-tunnel-source-new-symdef.h"
> +
> +PA_MODULE_AUTHOR("Alexander Couzens");
> +PA_MODULE_DESCRIPTION("Create a network source which connects via a stream to a remote PulseAudio server");
> +PA_MODULE_VERSION(PACKAGE_VERSION);
> +PA_MODULE_LOAD_ONCE(false);
> +PA_MODULE_USAGE(
> +        "server=<address> "
> +        "source=<name of the remote source> "
> +        "source_name=<name for the local source> "
> +        "source_properties=<properties for the local source> "
> +        "format=<sample format> "
> +        "channels=<number of channels> "
> +        "rate=<sample rate> "
> +        "channel_map=<channel map>"
> +        );
> +
> +#define TUNNEL_THREAD_FAILED_MAINLOOP 1
> +
> +static void stream_state_cb(pa_stream *stream, void *userdata);
> +static void stream_read_cb(pa_stream *s, size_t length, void *userdata);
> +static void context_state_cb(pa_context *c, void *userdata);
> +static void source_update_requested_latency_cb(pa_source *s);
> +
> +struct userdata {
> +    pa_module *module;
> +    pa_source *source;
> +    pa_thread *thread;
> +    pa_thread_mq thread_mq;
> +    pa_mainloop *thread_mainloop;
> +    pa_mainloop_api *thread_mainloop_api;
> +
> +    pa_context *context;
> +    pa_stream *stream;
> +
> +    bool update_stream_bufferattr_after_connect;
> +    bool connected;
> +    bool new_data;
> +
> +    char *remote_server;
> +    char *remote_source_name;
> +};
> +
> +static const char* const valid_modargs[] = {
> +    "source_name",
> +    "source_properties",
> +    "server",
> +    "source",
> +    "format",
> +    "channels",
> +    "rate",
> +    "channel_map",
> +   /* "cookie", unimplemented */
> +   /* "reconnect", reconnect if server comes back again - unimplemented */
> +    NULL,
> +};
> +
> +static void reset_bufferattr(pa_buffer_attr *bufferattr) {
> +    pa_assert(bufferattr);
> +    bufferattr->fragsize = (uint32_t) -1;
> +    bufferattr->minreq = (uint32_t) -1;
> +    bufferattr->maxlength = (uint32_t) -1;
> +    bufferattr->prebuf = (uint32_t) -1;
> +    bufferattr->tlength = (uint32_t) -1;
> +}
> +
> +static pa_proplist* tunnel_new_proplist(struct userdata *u) {
> +    pa_proplist *proplist = pa_proplist_new();
> +    pa_assert(proplist);
> +    pa_proplist_sets(proplist, PA_PROP_APPLICATION_NAME, "PulseAudio");
> +    pa_proplist_sets(proplist, PA_PROP_APPLICATION_ID, "org.PulseAudio.PulseAudio");
> +    pa_proplist_sets(proplist, PA_PROP_APPLICATION_VERSION, PACKAGE_VERSION);
> +    pa_init_proplist(proplist);
> +
> +    return proplist;
> +}
> +
> +static void stream_read_cb(pa_stream *s, size_t length, void *userdata) {
> +    struct userdata *u = userdata;
> +    u->new_data = true;
> +}
> +
> +/* called from io context to read samples from the stream into our source */
> +static void read_new_samples(struct userdata *u) {
> +    void *p;
> +    size_t read = 0;
> +    pa_memchunk memchunk;
> +
> +    pa_assert(u);
> +    u->new_data = false;
> +
> +    pa_memchunk_reset(&memchunk);
> +
> +    if (PA_UNLIKELY(!u->connected || pa_stream_get_state(u->stream) != PA_STREAM_READY))
> +        return;
> +
> +    read = pa_stream_readable_size(u->stream);
> +    if (PA_LIKELY(read > 0)) {
> +        if (PA_UNLIKELY(pa_stream_peek(u->stream, (const void**) &p, &read) != 0)) {

I think it would be better to declare p as const pointer to begin with,
so this cast would not be needed. The returned memory is owned by
pa_stream, so we should treat it as read-only, and thus const would be
appropriate.

That will probably make the compiler complain about giving a const
pointer to pa_memblock_new_fixed(), so a cast will be needed there, but
it's safe to do, because the memblock will be marked as read-only.

> +            pa_log("pa_stream_peek() failed: %s", pa_strerror(pa_context_errno(u->context)));
> +            u->thread_mainloop_api->quit(u->thread_mainloop_api, TUNNEL_THREAD_FAILED_MAINLOOP);
> +            return;
> +        }
> +
> +        memchunk.memblock = pa_memblock_new_fixed(u->module->core->mempool, p, read, true);

Before using p, you should check that it's not NULL. If you check the
pa_stream_peek() documentation, you'll find that the function may also
return a "hole", in which case p will be NULL. You should probably
generate silence if you receive a hole from pa_stream_peek().

> +        memchunk.length = read;
> +        memchunk.index = 0;
> +
> +        pa_source_post(u->source, &memchunk);
> +        pa_memblock_unref_fixed(memchunk.memblock);
> +
> +        pa_stream_drop(u->stream);
> +    }

I think the reading should be done in a loop, so that you read all
readable data in one go (there probably won't be more than one pass for
normal reads, though, but in case of holes there may be need for two
passes).

> +}
> +
> +static void thread_func(void *userdata) {
> +    struct userdata *u = userdata;
> +    pa_proplist *proplist;
> +
> +    pa_assert(u);
> +
> +    pa_log_debug("Thread starting up");
> +    pa_thread_mq_install(&u->thread_mq);
> +
> +    proplist = tunnel_new_proplist(u);
> +    u->context = pa_context_new_with_proplist(u->thread_mainloop_api,
> +                                              "PulseAudio",
> +                                              proplist);
> +    pa_proplist_free(proplist);
> +
> +    if (!u->context) {
> +        pa_log("Failed to create libpulse context");
> +        goto fail;
> +    }
> +
> +    pa_context_set_state_callback(u->context, context_state_cb, u);
> +    if (pa_context_connect(u->context,
> +                           u->remote_server,
> +                           PA_CONTEXT_NOAUTOSPAWN,
> +                           NULL) < 0) {
> +        pa_log("Failed to connect libpulse context");

It would be good to include the error from the context in the log
message.

> +        goto fail;
> +    }
> +
> +    for (;;) {
> +        int ret;
> +
> +        if (pa_mainloop_iterate(u->thread_mainloop, 1, &ret) < 0) {
> +            if (ret == 0)
> +                goto finish;
> +            else
> +                goto fail;
> +        }
> +
> +        if (u->new_data)
> +            read_new_samples(u);
> +    }
> +fail:
> +    pa_asyncmsgq_post(u->thread_mq.outq, PA_MSGOBJECT(u->module->core), PA_CORE_MESSAGE_UNLOAD_MODULE, u->module, 0, NULL, NULL);
> +    pa_asyncmsgq_wait_for(u->thread_mq.inq, PA_MESSAGE_SHUTDOWN);
> +
> +finish:
> +    if (u->stream) {
> +        pa_stream_disconnect(u->stream);
> +        pa_stream_unref(u->stream);
> +        u->stream = NULL;
> +    }
> +
> +    if (u->context) {
> +        pa_context_disconnect(u->context);
> +        pa_context_unref(u->context);
> +        u->context = NULL;
> +    }
> +
> +    pa_log_debug("Thread shutting down");
> +}
> +
> +static void stream_state_cb(pa_stream *stream, void *userdata) {
> +    struct userdata *u = userdata;
> +
> +    pa_assert(u);
> +
> +    switch (pa_stream_get_state(stream)) {
> +        case PA_STREAM_FAILED:
> +            pa_log_error("Stream failed.");

It would be good to include the error from the context in the log
message.

> +            u->connected = false;
> +            u->thread_mainloop_api->quit(u->thread_mainloop_api, TUNNEL_THREAD_FAILED_MAINLOOP);
> +            break;
> +        case PA_STREAM_TERMINATED:
> +            pa_log_debug("Stream terminated.");
> +            break;
> +        case PA_STREAM_READY:
> +            /* Only call our requested_latency_cb when requested_latency
> +             * changed between PA_STREAM_CREATING -> PA_STREAM_READY, because
> +             * we don't want to override the initial fragsize set by the server
> +             * without a good reason. */
> +            if (u->update_stream_bufferattr_after_connect)
> +                source_update_requested_latency_cb(u->source);
> +        default:
> +            break;

The default section is now used to handle the UNCONNECTED and CREATING
states. I would prefer handling all cases explicitly, and dropping the
default section.

> +    }
> +}
> +
> +static void context_state_cb(pa_context *c, void *userdata) {
> +    struct userdata *u = userdata;
> +    pa_assert(u);
> +
> +    switch (pa_context_get_state(c)) {
> +        case PA_CONTEXT_UNCONNECTED:
> +        case PA_CONTEXT_CONNECTING:
> +        case PA_CONTEXT_AUTHORIZING:
> +        case PA_CONTEXT_SETTING_NAME:
> +            break;
> +        case PA_CONTEXT_READY: {
> +            pa_proplist *proplist;
> +            pa_buffer_attr bufferattr;
> +            pa_usec_t requested_latency;
> +            const char *username = pa_get_user_name_malloc();
> +            const char *hostname = pa_get_host_name_malloc();

As the function names imply, the returned strings for username and
hostname are newly allocated, so you need to free them after use.

> +            /* TODO: old tunnel put here the remote source_name into stream name e.g. 'Null Output for lynxis at lazus' */
> +            char *stream_name = pa_sprintf_malloc(_("Tunnel for %s@%s"), username, hostname);
> +
> +            pa_log_debug("Connection successful. Creating stream.");
> +            pa_assert(!u->stream);
> +
> +            proplist = tunnel_new_proplist(u);
> +            u->stream = pa_stream_new_with_proplist(u->context,
> +                                                    stream_name,
> +                                                    &u->source->sample_spec,
> +                                                    &u->source->channel_map,
> +                                                    proplist);
> +            pa_proplist_free(proplist);
> +            pa_xfree(stream_name);
> +
> +            if (!u->stream) {
> +                pa_log_error("Could not create a stream.");

It would be good to include the error from the context in the log
message.

> +                u->thread_mainloop_api->quit(u->thread_mainloop_api, TUNNEL_THREAD_FAILED_MAINLOOP);
> +                return;
> +            }
> +
> +            requested_latency = pa_source_get_requested_latency_within_thread(u->source);
> +            if (requested_latency == (uint32_t) -1)
> +                requested_latency = u->source->thread_info.max_latency;
> +
> +            reset_bufferattr(&bufferattr);
> +            bufferattr.fragsize = pa_usec_to_bytes(requested_latency, &u->source->sample_spec);
> +
> +            pa_stream_set_state_callback(u->stream, stream_state_cb, userdata);
> +            pa_stream_set_read_callback(u->stream, stream_read_cb, userdata);
> +            if (pa_stream_connect_record(u->stream,
> +                                         u->remote_source_name,
> +                                         &bufferattr,
> +                                         PA_STREAM_INTERPOLATE_TIMING|PA_STREAM_DONT_MOVE|PA_STREAM_AUTO_TIMING_UPDATE) < 0) {
> +                pa_log_debug("Could not create stream.");

It would be good to include the error from the context in the log
message.

> +                u->thread_mainloop_api->quit(u->thread_mainloop_api, TUNNEL_THREAD_FAILED_MAINLOOP);
> +            }
> +            u->connected = true;
> +            break;
> +        }
> +        case PA_CONTEXT_FAILED:
> +            pa_log_debug("Context failed with err %s.", pa_strerror(pa_context_errno(u->context)));
> +            u->connected = false;
> +            u->thread_mainloop_api->quit(u->thread_mainloop_api, TUNNEL_THREAD_FAILED_MAINLOOP);
> +            break;
> +        case PA_CONTEXT_TERMINATED:
> +            pa_log_debug("Context terminated.");
> +            u->connected = false;
> +            u->thread_mainloop_api->quit(u->thread_mainloop_api, TUNNEL_THREAD_FAILED_MAINLOOP);
> +            break;
> +        default:
> +            break;

The default section is not useful, and prevents useful compiler warnings
about non-handled cases.

> +    }
> +}
> +
> +static void source_update_requested_latency_cb(pa_source *s) {
> +    struct userdata *u;
> +    pa_operation *operation;
> +    size_t nbytes;
> +    pa_usec_t block_usec;
> +    pa_buffer_attr bufferattr;
> +
> +    pa_source_assert_ref(s);
> +    pa_assert_se(u = s->userdata);
> +
> +    block_usec = pa_source_get_requested_latency_within_thread(s);
> +    if (block_usec == (pa_usec_t) -1)
> +        block_usec = s->thread_info.max_latency;
> +
> +    nbytes = pa_usec_to_bytes(block_usec, &s->sample_spec);
> +
> +    if (u->stream) {
> +        switch (pa_stream_get_state(u->stream)) {
> +            case PA_STREAM_READY:
> +                if (pa_stream_get_buffer_attr(u->stream)->fragsize == nbytes)
> +                    break;
> +
> +                reset_bufferattr(&bufferattr);
> +                bufferattr.fragsize = nbytes;
> +                if ((operation = pa_stream_set_buffer_attr(u->stream, &bufferattr, NULL, NULL)))
> +                    pa_operation_unref(operation);
> +                break;
> +            case PA_STREAM_CREATING:
> +                /* we have to delay our request until stream is ready */
> +                u->update_stream_bufferattr_after_connect = true;
> +                break;
> +            default:
> +                break;
> +        }
> +    }
> +}
> +
> +static int source_process_msg_cb(pa_msgobject *o, int code, void *data, int64_t offset, pa_memchunk *chunk) {
> +    struct userdata *u = PA_SOURCE(o)->userdata;
> +
> +    switch (code) {
> +        case PA_SOURCE_MESSAGE_GET_LATENCY: {
> +            int negative;
> +            pa_usec_t remote_latency;
> +
> +            if (!PA_SOURCE_IS_LINKED(u->source->thread_info.state)) {
> +                *((pa_usec_t*) data) = 0;
> +                return 0;
> +            }
> +
> +            if (!u->stream) {
> +                *((pa_usec_t*) data) = 0;
> +                return 0;
> +            }
> +
> +            if (pa_stream_get_state(u->stream) != PA_STREAM_READY) {
> +                *((pa_usec_t*) data) = 0;
> +                return 0;
> +            }
> +
> +            if (pa_stream_get_latency(u->stream, &remote_latency, &negative) < 0) {
> +                *((pa_usec_t*) data) = 0;
> +                return 0;
> +            }
> +
> +            *((pa_usec_t*) data) = remote_latency;

pa_stream_get_latency() can return a negative latency, in which case you
should return zero latency here.

> +            return 0;
> +        }
> +    }
> +    return pa_source_process_msg(o, code, data, offset, chunk);
> +}
> +
> +int pa__init(pa_module *m) {
> +    struct userdata *u = NULL;
> +    pa_modargs *ma = NULL;
> +    pa_source_new_data source_data;
> +    pa_sample_spec ss;
> +    pa_channel_map map;
> +    const char *remote_server = NULL;
> +    const char *source_name = NULL;
> +    char *default_source_name = NULL;
> +
> +    pa_assert(m);
> +
> +    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
> +        pa_log("Failed to parse module arguments.");
> +        goto fail;
> +    }
> +
> +    ss = m->core->default_sample_spec;
> +    map = m->core->default_channel_map;
> +    if (pa_modargs_get_sample_spec_and_channel_map(ma, &ss, &map, PA_CHANNEL_MAP_DEFAULT) < 0) {
> +        pa_log("Invalid sample format specification or channel map");
> +        goto fail;
> +    }
> +
> +    remote_server = pa_modargs_get_value(ma, "server", NULL);
> +    if (!remote_server) {
> +        pa_log("No server given!");
> +        goto fail;
> +    }
> +
> +    u = pa_xnew0(struct userdata, 1);
> +    u->module = m;
> +    m->userdata = u;
> +    u->remote_server = pa_xstrdup(remote_server);
> +    u->thread_mainloop = pa_mainloop_new();
> +    if (u->thread_mainloop == NULL) {
> +        pa_log("Failed to create mainloop");
> +        goto fail;
> +    }
> +    u->thread_mainloop_api = pa_mainloop_get_api(u->thread_mainloop);
> +    u->remote_source_name = pa_xstrdup(pa_modargs_get_value(ma, "source", NULL));
> +
> +    pa_thread_mq_init_thread_mainloop(&u->thread_mq, m->core->mainloop, u->thread_mainloop_api);
> +
> +    /* Create source */
> +    pa_source_new_data_init(&source_data);
> +    source_data.driver = __FILE__;
> +    source_data.module = m;
> +
> +    default_source_name = pa_sprintf_malloc("tunnel-source-new.%s", remote_server);
> +    source_name = pa_modargs_get_value(ma, "source_name", default_source_name);
> +
> +    pa_source_new_data_set_name(&source_data, source_name);
> +    pa_source_new_data_set_sample_spec(&source_data, &ss);
> +    pa_source_new_data_set_channel_map(&source_data, &map);
> +
> +    pa_proplist_sets(source_data.proplist, PA_PROP_DEVICE_CLASS, "sound");
> +    pa_proplist_setf(source_data.proplist,
> +                     PA_PROP_DEVICE_DESCRIPTION,
> +                     _("Tunnel to %s/%s"),
> +                     remote_server,
> +                     pa_strempty(u->remote_source_name));
> +
> +    if (pa_modargs_get_proplist(ma, "source_properties", source_data.proplist, PA_UPDATE_REPLACE) < 0) {
> +        pa_log("Invalid properties");
> +        pa_source_new_data_done(&source_data);
> +        goto fail;
> +    }
> +    if (!(u->source = pa_source_new(m->core, &source_data, PA_SOURCE_LATENCY | PA_SOURCE_DYNAMIC_LATENCY | PA_SOURCE_NETWORK))) {
> +        pa_log("Failed to create source.");
> +        pa_source_new_data_done(&source_data);
> +        goto fail;
> +    }
> +
> +    pa_source_new_data_done(&source_data);
> +    u->source->userdata = u;
> +    u->source->parent.process_msg = source_process_msg_cb;
> +    u->source->update_requested_latency = source_update_requested_latency_cb;
> +
> +    pa_source_set_asyncmsgq(u->source, u->thread_mq.inq);
> +
> +    if (!(u->thread = pa_thread_new("tunnel-source", thread_func, u))) {
> +        pa_log("Failed to create thread.");
> +        goto fail;
> +    }
> +
> +    pa_source_put(u->source);
> +    pa_modargs_free(ma);
> +    pa_xfree(default_source_name);
> +
> +    return 0;
> +
> +fail:
> +    if (ma)
> +        pa_modargs_free(ma);
> +
> +    if (default_source_name)
> +        pa_xfree(default_source_name);
> +
> +    pa__done(m);
> +
> +    return -1;
> +}
> +
> +void pa__done(pa_module *m) {
> +    struct userdata *u;
> +
> +    pa_assert(m);
> +
> +    if (!(u = m->userdata))
> +        return;
> +
> +    if (u->source)
> +        pa_source_unlink(u->source);
> +
> +    if (u->thread) {
> +        pa_asyncmsgq_send(u->thread_mq.inq, NULL, PA_MESSAGE_SHUTDOWN, NULL, 0, NULL);
> +        pa_thread_free(u->thread);
> +    }
> +
> +    pa_thread_mq_done(&u->thread_mq);

This will crash if u->thread_mq hasn't been initialized. The easiest way
to fix this is to move the initialization of thread_mq to happen a bit
earlier.

As a sidenote (only tangentially related to your patch), I think it
would be better if the allocation and initialization of thread_mq would
be done with the pa_foo_new() style instead of the pa_foo_init() style.
Having a pointer in userdata instead of embedding the struct directly
would make it possible to easily check whether the object has been
initialized or not.

-- 
Tanu



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