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1 /***
2   This file is part of PulseAudio.
3 
4   Copyright 2004-2008 Lennart Poettering
5   Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
6 
7   PulseAudio is free software; you can redistribute it and/or modify
8   it under the terms of the GNU Lesser General Public License as published
9   by the Free Software Foundation; either version 2 of the License,
10   or (at your option) any later version.
11 
12   PulseAudio is distributed in the hope that it will be useful, but
13   WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15   General Public License for more details.
16 
17   You should have received a copy of the GNU Lesser General Public License
18   along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
19 ***/
20 
21 #ifdef HAVE_CONFIG_H
22 #include <config.h>
23 #endif
24 
25 #include <stdlib.h>
26 #include <stdio.h>
27 #include <errno.h>
28 #include <unistd.h>
29 
30 #include <pulse/rtclock.h>
31 #include <pulse/timeval.h>
32 #include <pulse/util.h>
33 #include <pulse/xmalloc.h>
34 
35 #include <pulsecore/core-util.h>
36 #include <pulsecore/log.h>
37 #include <pulsecore/macro.h>
38 #include <pulsecore/modargs.h>
39 #include <pulsecore/module.h>
40 #include <pulsecore/rtpoll.h>
41 #include <pulsecore/source.h>
42 #include <pulsecore/thread-mq.h>
43 #include <pulsecore/thread.h>
44 
45 PA_MODULE_AUTHOR("Lennart Poettering & Marc-Andre Lureau");
46 PA_MODULE_DESCRIPTION("Clocked NULL source");
47 PA_MODULE_VERSION(PACKAGE_VERSION);
48 PA_MODULE_LOAD_ONCE(false);
49 PA_MODULE_USAGE(
50         "format=<sample format> "
51         "channels=<number of channels> "
52         "rate=<sample rate> "
53         "source_name=<name of source> "
54         "channel_map=<channel map> "
55         "description=<description for the source> ");
56 
57 #define DEFAULT_SOURCE_NAME "source.null"
58 #define MAX_LATENCY_USEC (PA_USEC_PER_SEC * 2)
59 #define MIN_LATENCY_USEC (500)
60 
61 struct userdata {
62     pa_core *core;
63     pa_module *module;
64     pa_source *source;
65 
66     pa_thread *thread;
67     pa_thread_mq thread_mq;
68     pa_rtpoll *rtpoll;
69 
70     size_t block_size;
71 
72     pa_usec_t block_usec;
73     pa_usec_t timestamp;
74 };
75 
76 static const char* const valid_modargs[] = {
77     "rate",
78     "format",
79     "channels",
80     "source_name",
81     "channel_map",
82     "description",
83     NULL
84 };
85 
source_process_msg(pa_msgobject * o,int code,void * data,int64_t offset,pa_memchunk * chunk)86 static int source_process_msg(pa_msgobject *o, int code, void *data, int64_t offset, pa_memchunk *chunk) {
87     struct userdata *u = PA_SOURCE(o)->userdata;
88 
89     switch (code) {
90         case PA_SOURCE_MESSAGE_GET_LATENCY: {
91             pa_usec_t now;
92 
93             now = pa_rtclock_now();
94             *((int64_t*) data) = (int64_t)now - (int64_t)u->timestamp;
95 
96             return 0;
97         }
98     }
99 
100     return pa_source_process_msg(o, code, data, offset, chunk);
101 }
102 
103 /* Called from the IO thread. */
source_set_state_in_io_thread_cb(pa_source * s,pa_source_state_t new_state,pa_suspend_cause_t new_suspend_cause)104 static int source_set_state_in_io_thread_cb(pa_source *s, pa_source_state_t new_state, pa_suspend_cause_t new_suspend_cause) {
105     struct userdata *u;
106 
107     pa_assert(s);
108     pa_assert_se(u = s->userdata);
109 
110     if (s->thread_info.state == PA_SOURCE_SUSPENDED || s->thread_info.state == PA_SOURCE_INIT) {
111         if (PA_SOURCE_IS_OPENED(new_state))
112             u->timestamp = pa_rtclock_now();
113     }
114 
115     return 0;
116 }
117 
source_update_requested_latency_cb(pa_source * s)118 static void source_update_requested_latency_cb(pa_source *s) {
119     struct userdata *u;
120 
121     pa_source_assert_ref(s);
122     u = s->userdata;
123     pa_assert(u);
124 
125     u->block_usec = pa_source_get_requested_latency_within_thread(s);
126     if (u->block_usec == (pa_usec_t)-1)
127         u->block_usec = u->source->thread_info.max_latency;
128 }
129 
thread_func(void * userdata)130 static void thread_func(void *userdata) {
131     struct userdata *u = userdata;
132     bool timer_elapsed = false;
133     size_t max_block_size;
134 
135     pa_assert(u);
136 
137     pa_log_debug("Thread starting up");
138 
139     if (u->core->realtime_scheduling)
140         pa_thread_make_realtime(u->core->realtime_priority);
141 
142     pa_thread_mq_install(&u->thread_mq);
143 
144     max_block_size = pa_frame_align(pa_mempool_block_size_max(u->core->mempool), &u->source->sample_spec);
145     u->timestamp = pa_rtclock_now();
146 
147     for (;;) {
148         int ret;
149 
150         /* Generate some null data */
151         if (PA_SOURCE_IS_OPENED(u->source->thread_info.state)) {
152             pa_usec_t now;
153             pa_memchunk chunk;
154 
155             now = pa_rtclock_now();
156 
157             if (timer_elapsed && (chunk.length = pa_usec_to_bytes(now - u->timestamp, &u->source->sample_spec)) > 0) {
158 
159                 chunk.length = PA_MIN(max_block_size, chunk.length);
160 
161                 chunk.memblock = pa_memblock_new(u->core->mempool, chunk.length);
162                 chunk.index = 0;
163                 pa_silence_memchunk(&chunk, &u->source->sample_spec);
164                 pa_source_post(u->source, &chunk);
165                 pa_memblock_unref(chunk.memblock);
166 
167                 u->timestamp += pa_bytes_to_usec(chunk.length, &u->source->sample_spec);
168             }
169 
170             pa_rtpoll_set_timer_absolute(u->rtpoll, u->timestamp + u->block_usec);
171         } else
172             pa_rtpoll_set_timer_disabled(u->rtpoll);
173 
174         /* Hmm, nothing to do. Let's sleep */
175         if ((ret = pa_rtpoll_run(u->rtpoll)) < 0)
176             goto fail;
177 
178         timer_elapsed = pa_rtpoll_timer_elapsed(u->rtpoll);
179 
180         if (ret == 0)
181             goto finish;
182     }
183 
184 fail:
185     /* If this was no regular exit from the loop we have to continue
186      * processing messages until we received PA_MESSAGE_SHUTDOWN */
187     pa_asyncmsgq_post(u->thread_mq.outq, PA_MSGOBJECT(u->core), PA_CORE_MESSAGE_UNLOAD_MODULE, u->module, 0, NULL, NULL);
188     pa_asyncmsgq_wait_for(u->thread_mq.inq, PA_MESSAGE_SHUTDOWN);
189 
190 finish:
191     pa_log_debug("Thread shutting down");
192 }
193 
pa__init(pa_module * m)194 int pa__init(pa_module*m) {
195     struct userdata *u = NULL;
196     pa_sample_spec ss;
197     pa_channel_map map;
198     pa_modargs *ma = NULL;
199     pa_source_new_data data;
200 
201     pa_assert(m);
202 
203     if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
204         pa_log("Failed to parse module arguments.");
205         goto fail;
206     }
207 
208     ss = m->core->default_sample_spec;
209     map = m->core->default_channel_map;
210     if (pa_modargs_get_sample_spec_and_channel_map(ma, &ss, &map, PA_CHANNEL_MAP_DEFAULT) < 0) {
211         pa_log("Invalid sample format specification or channel map");
212         goto fail;
213     }
214 
215     m->userdata = u = pa_xnew0(struct userdata, 1);
216     u->core = m->core;
217     u->module = m;
218     u->rtpoll = pa_rtpoll_new();
219 
220     if (pa_thread_mq_init(&u->thread_mq, m->core->mainloop, u->rtpoll) < 0) {
221         pa_log("pa_thread_mq_init() failed.");
222         goto fail;
223     }
224 
225     pa_source_new_data_init(&data);
226     data.driver = __FILE__;
227     data.module = m;
228     pa_source_new_data_set_name(&data, pa_modargs_get_value(ma, "source_name", DEFAULT_SOURCE_NAME));
229     pa_source_new_data_set_sample_spec(&data, &ss);
230     pa_source_new_data_set_channel_map(&data, &map);
231     pa_proplist_sets(data.proplist, PA_PROP_DEVICE_DESCRIPTION, pa_modargs_get_value(ma, "description", "Null Input"));
232     pa_proplist_sets(data.proplist, PA_PROP_DEVICE_CLASS, "abstract");
233 
234     u->source = pa_source_new(m->core, &data, PA_SOURCE_LATENCY | PA_SOURCE_DYNAMIC_LATENCY);
235     pa_source_new_data_done(&data);
236 
237     if (!u->source) {
238         pa_log("Failed to create source object.");
239         goto fail;
240     }
241 
242     u->source->parent.process_msg = source_process_msg;
243     u->source->set_state_in_io_thread = source_set_state_in_io_thread_cb;
244     u->source->update_requested_latency = source_update_requested_latency_cb;
245     u->source->userdata = u;
246 
247     pa_source_set_asyncmsgq(u->source, u->thread_mq.inq);
248     pa_source_set_rtpoll(u->source, u->rtpoll);
249 
250     pa_source_set_latency_range(u->source, MIN_LATENCY_USEC, MAX_LATENCY_USEC);
251     u->block_usec = u->source->thread_info.max_latency;
252 
253     u->source->thread_info.max_rewind =
254         pa_usec_to_bytes(u->block_usec, &u->source->sample_spec);
255 
256     if (!(u->thread = pa_thread_new("null-source", thread_func, u))) {
257         pa_log("Failed to create thread.");
258         goto fail;
259     }
260 
261     pa_source_put(u->source);
262 
263     pa_modargs_free(ma);
264 
265     return 0;
266 
267 fail:
268     if (ma)
269         pa_modargs_free(ma);
270 
271     pa__done(m);
272 
273     return -1;
274 }
275 
pa__done(pa_module * m)276 void pa__done(pa_module*m) {
277     struct userdata *u;
278 
279     pa_assert(m);
280 
281     if (!(u = m->userdata))
282         return;
283 
284     if (u->source)
285         pa_source_unlink(u->source);
286 
287     if (u->thread) {
288         pa_asyncmsgq_send(u->thread_mq.inq, NULL, PA_MESSAGE_SHUTDOWN, NULL, 0, NULL);
289         pa_thread_free(u->thread);
290     }
291 
292     pa_thread_mq_done(&u->thread_mq);
293 
294     if (u->source)
295         pa_source_unref(u->source);
296 
297     if (u->rtpoll)
298         pa_rtpoll_free(u->rtpoll);
299 
300     pa_xfree(u);
301 }
302