[pulseaudio-discuss] [PATCH 5/6] protocol-native: Add signal receiving capability
Georg Chini
georg at chini.tk
Sat Aug 19 15:48:05 UTC 2017
This patch extends the client subscription API, so that signals sent from
PulseAudio can be processed. Within PulseAudio, a signal can be emitted
using pa_signal_post(). The interface can be used to notify the client of
events that are not covered by the subscription API (for example a button
press event on a bluetooth headset).
Setting up signal notification is very similar to using subscriptions.
First the client needs to subscribe with pa_context_subscribe_signals()
and then sets up a signal handler using pa_context_set_signal_callback().
The signal handler will receive three arguments in addition to the usual
context and userdata:
sender - string that specifies the origin of the signal
signal - string that specifies the type of the signal
signal_parameters - optional string for additional information
---
PROTOCOL | 3 ++
src/map-file | 2 ++
src/pulse/def.h | 4 +++
src/pulse/internal.h | 2 ++
src/pulse/subscribe.c | 66 +++++++++++++++++++++++++++++++++++++----
src/pulse/subscribe.h | 9 ++++++
src/pulsecore/core-messages.c | 23 ++++++++++++++
src/pulsecore/core-messages.h | 11 +++++++
src/pulsecore/core.h | 1 +
src/pulsecore/native-common.h | 1 +
src/pulsecore/pdispatch.c | 1 +
src/pulsecore/protocol-native.c | 57 +++++++++++++++++++++++++++++++++++
12 files changed, 174 insertions(+), 6 deletions(-)
diff --git a/PROTOCOL b/PROTOCOL
index ccd3cd2c..e9337e27 100644
--- a/PROTOCOL
+++ b/PROTOCOL
@@ -427,6 +427,9 @@ Added new command for communication with objects.
PA_COMMAND_SEND_OBJECT_MESSAGE:
sends a message to an object that registered a named message handler
+Added signal subscription functions. Clients can now subscribe to signals
+that PulseAudio sends.
+
#### If you just changed the protocol, read this
## module-tunnel depends on the sink/source/sink-input/source-input protocol
## internals, so if you changed these, you might have broken module-tunnel.
diff --git a/src/map-file b/src/map-file
index 4e78c1f9..83301eba 100644
--- a/src/map-file
+++ b/src/map-file
@@ -111,8 +111,10 @@ pa_context_set_source_volume_by_index;
pa_context_set_source_volume_by_name;
pa_context_set_state_callback;
pa_context_set_subscribe_callback;
+pa_context_set_signal_callback;
pa_context_stat;
pa_context_subscribe;
+pa_context_subscribe_signals;
pa_context_suspend_sink_by_index;
pa_context_suspend_sink_by_name;
pa_context_suspend_source_by_index;
diff --git a/src/pulse/def.h b/src/pulse/def.h
index 680bdc98..a26f2385 100644
--- a/src/pulse/def.h
+++ b/src/pulse/def.h
@@ -599,6 +599,9 @@ typedef enum pa_subscription_event_type {
PA_SUBSCRIPTION_EVENT_REMOVE = 0x0020U,
/**< An object was removed */
+ PA_SUBSCRIPTION_EVENT_SIGNAL = 0x0040U,
+ /** A signal was issued */
+
PA_SUBSCRIPTION_EVENT_TYPE_MASK = 0x0030U
/**< A mask to extract the event operation from an event value */
@@ -634,6 +637,7 @@ typedef enum pa_subscription_event_type {
#define PA_SUBSCRIPTION_EVENT_NEW PA_SUBSCRIPTION_EVENT_NEW
#define PA_SUBSCRIPTION_EVENT_CHANGE PA_SUBSCRIPTION_EVENT_CHANGE
#define PA_SUBSCRIPTION_EVENT_REMOVE PA_SUBSCRIPTION_EVENT_REMOVE
+#define PA_SUBSCRIPTION_EVENT_SIGNAL PA_SUBSCRIPTION_EVENT_SIGNAL
#define PA_SUBSCRIPTION_EVENT_TYPE_MASK PA_SUBSCRIPTION_EVENT_TYPE_MASK
/** \endcond */
diff --git a/src/pulse/internal.h b/src/pulse/internal.h
index 01d2b6e4..7d024cb1 100644
--- a/src/pulse/internal.h
+++ b/src/pulse/internal.h
@@ -89,6 +89,8 @@ struct pa_context {
void *subscribe_userdata;
pa_context_event_cb_t event_callback;
void *event_userdata;
+ pa_context_signal_cb_t signal_callback;
+ void *signal_userdata;
pa_mempool *mempool;
diff --git a/src/pulse/subscribe.c b/src/pulse/subscribe.c
index e7cce2e3..d9fd2e65 100644
--- a/src/pulse/subscribe.c
+++ b/src/pulse/subscribe.c
@@ -32,7 +32,6 @@
void pa_command_subscribe_event(pa_pdispatch *pd, uint32_t command, uint32_t tag, pa_tagstruct *t, void *userdata) {
pa_context *c = userdata;
pa_subscription_event_type_t e;
- uint32_t idx;
pa_assert(pd);
pa_assert(command == PA_COMMAND_SUBSCRIBE_EVENT);
@@ -42,15 +41,39 @@ void pa_command_subscribe_event(pa_pdispatch *pd, uint32_t command, uint32_t tag
pa_context_ref(c);
- if (pa_tagstruct_getu32(t, &e) < 0 ||
- pa_tagstruct_getu32(t, &idx) < 0 ||
- !pa_tagstruct_eof(t)) {
+ if (pa_tagstruct_getu32(t, &e) < 0) {
pa_context_fail(c, PA_ERR_PROTOCOL);
goto finish;
}
- if (c->subscribe_callback)
- c->subscribe_callback(c, e, idx, c->subscribe_userdata);
+ if (e != PA_SUBSCRIPTION_EVENT_SIGNAL) {
+ uint32_t idx;
+
+ if (pa_tagstruct_getu32(t, &idx) < 0 ||
+ !pa_tagstruct_eof(t)) {
+ pa_context_fail(c, PA_ERR_PROTOCOL);
+ goto finish;
+ }
+
+ if (c->subscribe_callback)
+ c->subscribe_callback(c, e, idx, c->subscribe_userdata);
+
+ } else {
+ const char *sender;
+ const char *signal;
+ const char *signal_info;
+
+ if (pa_tagstruct_gets(t, &sender) < 0 ||
+ pa_tagstruct_gets(t, &signal) < 0 ||
+ pa_tagstruct_gets(t, &signal_info) < 0 ||
+ !pa_tagstruct_eof(t)) {
+ pa_context_fail(c, PA_ERR_PROTOCOL);
+ goto finish;
+ }
+
+ if (c->signal_callback)
+ c->signal_callback(c, sender, signal, signal_info, c->signal_userdata);
+ }
finish:
pa_context_unref(c);
@@ -86,3 +109,34 @@ void pa_context_set_subscribe_callback(pa_context *c, pa_context_subscribe_cb_t
c->subscribe_callback = cb;
c->subscribe_userdata = userdata;
}
+
+void pa_context_set_signal_callback(pa_context *c, pa_context_signal_cb_t cb, void *userdata) {
+ pa_assert(c);
+ pa_assert(PA_REFCNT_VALUE(c) >= 1);
+
+ if (c->state == PA_CONTEXT_TERMINATED || c->state == PA_CONTEXT_FAILED)
+ return;
+
+ c->signal_callback = cb;
+ c->signal_userdata = userdata;
+}
+
+pa_operation* pa_context_subscribe_signals(pa_context *c, uint64_t signal_mask, pa_context_success_cb_t cb, void *userdata) {
+ pa_operation *o;
+ pa_tagstruct *t;
+ uint32_t tag;
+
+ pa_assert(c);
+ pa_assert(PA_REFCNT_VALUE(c) >= 1);
+
+ PA_CHECK_VALIDITY_RETURN_NULL(c, c->state == PA_CONTEXT_READY, PA_ERR_BADSTATE);
+
+ o = pa_operation_new(c, NULL, (pa_operation_cb_t) cb, userdata);
+
+ t = pa_tagstruct_command(c, PA_COMMAND_SUBSCRIBE_SIGNALS, &tag);
+ pa_tagstruct_putu64(t, signal_mask);
+ pa_pstream_send_tagstruct(c->pstream, t);
+ pa_pdispatch_register_reply(c->pdispatch, tag, DEFAULT_TIMEOUT, pa_context_simple_ack_callback, pa_operation_ref(o), (pa_free_cb_t) pa_operation_unref);
+
+ return o;
+}
diff --git a/src/pulse/subscribe.h b/src/pulse/subscribe.h
index b43c8ea4..d4e03411 100644
--- a/src/pulse/subscribe.h
+++ b/src/pulse/subscribe.h
@@ -72,12 +72,21 @@ PA_C_DECL_BEGIN
/** Subscription event callback prototype */
typedef void (*pa_context_subscribe_cb_t)(pa_context *c, pa_subscription_event_type_t t, uint32_t idx, void *userdata);
+/** Signal event callback prototype */
+typedef void (*pa_context_signal_cb_t)(pa_context *c, const char *sender, const char *signal, const char *signal_info, void *userdata);
+
/** Enable event notification */
pa_operation* pa_context_subscribe(pa_context *c, pa_subscription_mask_t m, pa_context_success_cb_t cb, void *userdata);
+/** Enable signal notification */
+pa_operation* pa_context_subscribe_signals(pa_context *c, uint64_t signal_mask, pa_context_success_cb_t cb, void *userdata);
+
/** Set the context specific call back function that is called whenever the state of the daemon changes */
void pa_context_set_subscribe_callback(pa_context *c, pa_context_subscribe_cb_t cb, void *userdata);
+/** Set the context specific call back function that is called whenever pulseaudio sends a signal */
+void pa_context_set_signal_callback(pa_context *c, pa_context_signal_cb_t cb, void *userdata);
+
PA_C_DECL_END
#endif
diff --git a/src/pulsecore/core-messages.c b/src/pulsecore/core-messages.c
index eca1e6cf..2132a8e4 100644
--- a/src/pulsecore/core-messages.c
+++ b/src/pulsecore/core-messages.c
@@ -137,3 +137,26 @@ char *pa_core_message_handler_list(pa_core *c) {
return pa_strbuf_to_string_free(buf);
}
+
+/* Send a signal */
+void pa_signal_post(pa_core *c, const char *sender, uint64_t facility, const char *signal, const char *signal_parameters) {
+ pa_signal_descriptor *sd;
+
+ pa_assert(sender);
+ pa_assert(facility);
+ pa_assert(signal);
+
+ sd = pa_xnew(pa_signal_descriptor, 1);
+ sd->sender = pa_xstrdup(sender);
+ sd->facility = facility;
+ sd->signal = pa_xstrdup(signal);
+ sd->parameters = pa_xstrdup(signal_parameters);
+
+ if (pa_hook_fire(&c->hooks[PA_CORE_HOOK_SEND_SIGNAL], sd) != PA_HOOK_OK)
+ pa_log_warn("Sending signal %s from %s failed", signal, sender);
+
+ pa_xfree(sd->sender);
+ pa_xfree(sd->signal);
+ pa_xfree(sd->parameters);
+ pa_xfree(sd);
+}
diff --git a/src/pulsecore/core-messages.h b/src/pulsecore/core-messages.h
index 8e78e35e..70fb113c 100644
--- a/src/pulsecore/core-messages.h
+++ b/src/pulsecore/core-messages.h
@@ -39,6 +39,17 @@ typedef int (*pa_core_message_handler_cb_t)(
char **response,
void *userdata);
+/* Structure to pass signal information */
+typedef struct pa_signal_descriptor {
+ char *sender;
+ char *signal;
+ char *parameters;
+ uint64_t facility;
+} pa_signal_descriptor;
+
+/* Send a signal */
+void pa_signal_post(pa_core *c, const char *sender, uint64_t facility, const char *signal, const char *signal_parameters);
+
/* Handler registration */
void pa_core_message_handler_register(pa_core *c, const char *recipient_name, const char *description, pa_core_message_handler_cb_t cb, void *userdata);
void pa_core_message_handler_unregister(pa_core *c, const char *recipient_name);
diff --git a/src/pulsecore/core.h b/src/pulsecore/core.h
index bc8a371e..f578d07f 100644
--- a/src/pulsecore/core.h
+++ b/src/pulsecore/core.h
@@ -138,6 +138,7 @@ typedef enum pa_core_hook {
PA_CORE_HOOK_SAMPLE_CACHE_NEW,
PA_CORE_HOOK_SAMPLE_CACHE_CHANGED,
PA_CORE_HOOK_SAMPLE_CACHE_UNLINK,
+ PA_CORE_HOOK_SEND_SIGNAL,
PA_CORE_HOOK_MAX
} pa_core_hook_t;
diff --git a/src/pulsecore/native-common.h b/src/pulsecore/native-common.h
index c24dd666..06c7c576 100644
--- a/src/pulsecore/native-common.h
+++ b/src/pulsecore/native-common.h
@@ -71,6 +71,7 @@ enum {
PA_COMMAND_GET_SAMPLE_INFO,
PA_COMMAND_GET_SAMPLE_INFO_LIST,
PA_COMMAND_SUBSCRIBE,
+ PA_COMMAND_SUBSCRIBE_SIGNALS,
PA_COMMAND_SET_SINK_VOLUME,
PA_COMMAND_SET_SINK_INPUT_VOLUME,
diff --git a/src/pulsecore/pdispatch.c b/src/pulsecore/pdispatch.c
index 52970f58..22ea90c5 100644
--- a/src/pulsecore/pdispatch.c
+++ b/src/pulsecore/pdispatch.c
@@ -85,6 +85,7 @@ static const char *command_names[PA_COMMAND_MAX] = {
[PA_COMMAND_GET_SOURCE_OUTPUT_INFO] = "GET_SOURCE_OUTPUT_INFO",
[PA_COMMAND_GET_SOURCE_OUTPUT_INFO_LIST] = "GET_SOURCE_OUTPUT_INFO_LIST",
[PA_COMMAND_SUBSCRIBE] = "SUBSCRIBE",
+ [PA_COMMAND_SUBSCRIBE_SIGNALS] = "SUBSCRIBE_SIGNALS",
[PA_COMMAND_SET_SINK_VOLUME] = "SET_SINK_VOLUME",
[PA_COMMAND_SET_SINK_INPUT_VOLUME] = "SET_SINK_INPUT_VOLUME",
diff --git a/src/pulsecore/protocol-native.c b/src/pulsecore/protocol-native.c
index 6a09fd8b..b796f871 100644
--- a/src/pulsecore/protocol-native.c
+++ b/src/pulsecore/protocol-native.c
@@ -55,6 +55,7 @@
#include <pulsecore/sample-util.h>
#include <pulsecore/creds.h>
#include <pulsecore/core-util.h>
+#include <pulsecore/core-messages.h>
#include <pulsecore/ipacl.h>
#include <pulsecore/thread-mq.h>
#include <pulsecore/mem.h>
@@ -187,6 +188,7 @@ struct pa_native_connection {
pa_idxset *record_streams, *output_streams;
uint32_t rrobin_index;
pa_subscription *subscription;
+ uint64_t signal_mask;
pa_time_event *auth_timeout_event;
pa_srbchannel *srbpending;
};
@@ -204,6 +206,8 @@ struct pa_native_protocol {
pa_hook hooks[PA_NATIVE_HOOK_MAX];
pa_hashmap *extensions;
+
+ pa_hook_slot *signal_hook_slot;
};
enum {
@@ -3722,6 +3726,26 @@ static void command_subscribe(pa_pdispatch *pd, uint32_t command, uint32_t tag,
pa_pstream_send_simple_ack(c->pstream, tag);
}
+static void command_signal_subscribe(pa_pdispatch *pd, uint32_t command, uint32_t tag, pa_tagstruct *t, void *userdata) {
+ pa_native_connection *c = PA_NATIVE_CONNECTION(userdata);
+ uint64_t m;
+
+ pa_native_connection_assert_ref(c);
+ pa_assert(t);
+
+ if (pa_tagstruct_getu64(t, &m) < 0 ||
+ !pa_tagstruct_eof(t)) {
+ protocol_error(c);
+ return;
+ }
+
+ CHECK_VALIDITY(c->pstream, c->authorized, tag, PA_ERR_ACCESS);
+
+ c->signal_mask = m;
+
+ pa_pstream_send_simple_ack(c->pstream, tag);
+}
+
static void command_set_volume(
pa_pdispatch *pd,
uint32_t command,
@@ -4915,6 +4939,7 @@ static const pa_pdispatch_cb_t command_table[PA_COMMAND_MAX] = {
[PA_COMMAND_GET_SAMPLE_INFO_LIST] = command_get_info_list,
[PA_COMMAND_GET_SERVER_INFO] = command_get_server_info,
[PA_COMMAND_SUBSCRIBE] = command_subscribe,
+ [PA_COMMAND_SUBSCRIBE_SIGNALS] = command_signal_subscribe,
[PA_COMMAND_SET_SINK_VOLUME] = command_set_volume,
[PA_COMMAND_SET_SINK_INPUT_VOLUME] = command_set_volume,
@@ -5263,6 +5288,33 @@ void pa_native_protocol_disconnect(pa_native_protocol *p, pa_module *m) {
native_connection_unlink(c);
}
+static pa_hook_result_t native_protocol_signal_hook(pa_core *core, pa_signal_descriptor *sd, pa_native_protocol *p) {
+ pa_native_connection *c;
+ uint32_t idx;
+
+ pa_assert(p);
+ pa_assert(sd);
+
+ PA_IDXSET_FOREACH(c, p->connections, idx) {
+ if (sd->facility & c->signal_mask) {
+ pa_tagstruct *t;
+
+ pa_native_connection_assert_ref(c);
+
+ t = pa_tagstruct_new();
+ pa_tagstruct_putu32(t, PA_COMMAND_SUBSCRIBE_EVENT);
+ pa_tagstruct_putu32(t, (uint32_t) -1);
+ pa_tagstruct_putu32(t, PA_SUBSCRIPTION_EVENT_SIGNAL);
+ pa_tagstruct_puts(t, sd->sender);
+ pa_tagstruct_puts(t, sd->signal);
+ pa_tagstruct_puts(t, sd->parameters);
+ pa_pstream_send_tagstruct(c->pstream, t);
+ }
+ }
+
+ return PA_HOOK_OK;
+}
+
static pa_native_protocol* native_protocol_new(pa_core *c) {
pa_native_protocol *p;
pa_native_hook_t h;
@@ -5281,6 +5333,8 @@ static pa_native_protocol* native_protocol_new(pa_core *c) {
for (h = 0; h < PA_NATIVE_HOOK_MAX; h++)
pa_hook_init(&p->hooks[h], p);
+ p->signal_hook_slot = pa_hook_connect(&c->hooks[PA_CORE_HOOK_SEND_SIGNAL], PA_HOOK_NORMAL, (pa_hook_cb_t) native_protocol_signal_hook, p);
+
pa_assert_se(pa_shared_set(c, "native-protocol", p) >= 0);
return p;
@@ -5321,6 +5375,9 @@ void pa_native_protocol_unref(pa_native_protocol *p) {
pa_strlist_free(p->servers);
+ if (p->signal_hook_slot)
+ pa_hook_slot_free(p->signal_hook_slot);
+
for (h = 0; h < PA_NATIVE_HOOK_MAX; h++)
pa_hook_done(&p->hooks[h]);
--
2.11.0
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