1 /***
2 This file is part of PulseAudio.
3
4 Copyright 2008 Colin Guthrie
5
6 PulseAudio is free software; you can redistribute it and/or modify
7 it under the terms of the GNU Lesser General Public License as published
8 by the Free Software Foundation; either version 2.1 of the License,
9 or (at your option) any later version.
10
11 PulseAudio is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public License
17 along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
18 ***/
19
20 #ifdef HAVE_CONFIG_H
21 #include <config.h>
22 #endif
23
24 #include <pulse/xmalloc.h>
25
26 #include <pulsecore/core.h>
27 #include <pulsecore/core-util.h>
28 #include <pulsecore/i18n.h>
29 #include <pulsecore/sink.h>
30 #include <pulsecore/modargs.h>
31 #include <pulsecore/log.h>
32
33 PA_MODULE_AUTHOR("Colin Guthrie");
34 PA_MODULE_DESCRIPTION(_("Always keeps at least one sink loaded even if it's a null one"));
35 PA_MODULE_VERSION(PACKAGE_VERSION);
36 PA_MODULE_LOAD_ONCE(true);
37 PA_MODULE_USAGE(
38 "sink_name=<name of sink>");
39
40 #define DEFAULT_SINK_NAME "auto_null"
41
42 static const char* const valid_modargs[] = {
43 "sink_name",
44 NULL,
45 };
46
47 struct userdata {
48 uint32_t null_module;
49 bool ignore;
50 char *sink_name;
51 };
52
load_null_sink_if_needed(pa_core * c,pa_sink * sink,struct userdata * u)53 static void load_null_sink_if_needed(pa_core *c, pa_sink *sink, struct userdata* u) {
54 pa_sink *target;
55 uint32_t idx;
56 char *t;
57 pa_module *m;
58
59 pa_assert(c);
60 pa_assert(u);
61
62 if (u->null_module != PA_INVALID_INDEX)
63 return; /* We've already got a null-sink loaded */
64
65 /* Loop through all sinks and check to see if we have *any*
66 * sinks. Ignore the sink passed in (if it's not null), and
67 * don't count filter sinks. */
68 PA_IDXSET_FOREACH(target, c->sinks, idx)
69 if (!sink || ((target != sink) && !pa_sink_is_filter(target)))
70 break;
71
72 if (target)
73 return;
74
75 pa_log_debug("Autoloading null-sink as no other sinks detected.");
76
77 u->ignore = true;
78
79 t = pa_sprintf_malloc("sink_name=%s sink_properties='device.description=\"%s\"'", u->sink_name,
80 _("Dummy Output"));
81 pa_module_load(&m, c, "module-null-sink", t);
82 u->null_module = m ? m->index : PA_INVALID_INDEX;
83 pa_xfree(t);
84
85 u->ignore = false;
86
87 if (!m)
88 pa_log_warn("Unable to load module-null-sink");
89 }
90
put_hook_callback(pa_core * c,pa_sink * sink,void * userdata)91 static pa_hook_result_t put_hook_callback(pa_core *c, pa_sink *sink, void* userdata) {
92 struct userdata *u = userdata;
93
94 pa_assert(c);
95 pa_assert(sink);
96 pa_assert(u);
97
98 /* This is us detecting ourselves on load... just ignore this. */
99 if (u->ignore)
100 return PA_HOOK_OK;
101
102 /* There's no point in doing anything if the core is shut down anyway */
103 if (c->state == PA_CORE_SHUTDOWN)
104 return PA_HOOK_OK;
105
106 /* Auto-loaded null-sink not active, so ignoring newly detected sink. */
107 if (u->null_module == PA_INVALID_INDEX)
108 return PA_HOOK_OK;
109
110 /* This is us detecting ourselves on load in a different way... just ignore this too. */
111 if (sink->module && sink->module->index == u->null_module)
112 return PA_HOOK_OK;
113
114 /* We don't count filter sinks since they need a real sink */
115 if (pa_sink_is_filter(sink))
116 return PA_HOOK_OK;
117
118 pa_log_info("A new sink has been discovered. Unloading null-sink.");
119
120 pa_module_unload_request_by_index(c, u->null_module, true);
121 u->null_module = PA_INVALID_INDEX;
122
123 return PA_HOOK_OK;
124 }
125
unlink_hook_callback(pa_core * c,pa_sink * sink,void * userdata)126 static pa_hook_result_t unlink_hook_callback(pa_core *c, pa_sink *sink, void* userdata) {
127 struct userdata *u = userdata;
128
129 pa_assert(c);
130 pa_assert(sink);
131 pa_assert(u);
132
133 /* First check to see if it's our own null-sink that's been removed... */
134 if (u->null_module != PA_INVALID_INDEX && sink->module && sink->module->index == u->null_module) {
135 pa_log_debug("Autoloaded null-sink removed");
136 u->null_module = PA_INVALID_INDEX;
137 return PA_HOOK_OK;
138 }
139
140 /* There's no point in doing anything if the core is shut down anyway */
141 if (c->state == PA_CORE_SHUTDOWN)
142 return PA_HOOK_OK;
143
144 load_null_sink_if_needed(c, sink, u);
145
146 return PA_HOOK_OK;
147 }
148
pa__init(pa_module * m)149 int pa__init(pa_module*m) {
150 pa_modargs *ma = NULL;
151 struct userdata *u;
152
153 pa_assert(m);
154
155 if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
156 pa_log("Failed to parse module arguments");
157 return -1;
158 }
159
160 m->userdata = u = pa_xnew(struct userdata, 1);
161 u->sink_name = pa_xstrdup(pa_modargs_get_value(ma, "sink_name", DEFAULT_SINK_NAME));
162 pa_module_hook_connect(m, &m->core->hooks[PA_CORE_HOOK_SINK_PUT], PA_HOOK_LATE, (pa_hook_cb_t) put_hook_callback, u);
163 pa_module_hook_connect(m, &m->core->hooks[PA_CORE_HOOK_SINK_UNLINK], PA_HOOK_EARLY, (pa_hook_cb_t) unlink_hook_callback, u);
164 u->null_module = PA_INVALID_INDEX;
165 u->ignore = false;
166
167 pa_modargs_free(ma);
168
169 load_null_sink_if_needed(m->core, NULL, u);
170
171 return 0;
172 }
173
pa__done(pa_module * m)174 void pa__done(pa_module*m) {
175 struct userdata *u;
176
177 pa_assert(m);
178
179 if (!(u = m->userdata))
180 return;
181
182 if (u->null_module != PA_INVALID_INDEX && m->core->state != PA_CORE_SHUTDOWN)
183 pa_module_unload_request_by_index(m->core, u->null_module, true);
184
185 pa_xfree(u->sink_name);
186 pa_xfree(u);
187 }
188