1 /* snd_card_plugin.c
2 ** Copyright (c) 2019, The Linux Foundation.
3 **
4 ** Redistribution and use in source and binary forms, with or without
5 ** modification, are permitted provided that the following conditions are
6 ** met:
7 ** * Redistributions of source code must retain the above copyright
8 ** notice, this list of conditions and the following disclaimer.
9 ** * Redistributions in binary form must reproduce the above
10 ** copyright notice, this list of conditions and the following
11 ** disclaimer in the documentation and/or other materials provided
12 ** with the distribution.
13 ** * Neither the name of The Linux Foundation nor the names of its
14 ** contributors may be used to endorse or promote products derived
15 ** from this software without specific prior written permission.
16 **
17 ** THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
18 ** WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
19 ** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
20 ** ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
21 ** BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 ** CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 ** SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
24 ** BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25 ** WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
26 ** OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
27 ** IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 **/
29
30 #include "snd_card_plugin.h"
31
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <errno.h>
35
36 #define SND_DLSYM(h, p, s, err) \
37 do { \
38 err = 0; \
39 p = dlsym(h, s); \
40 if (!p) \
41 err = -ENODEV; \
42 } while(0)
43
snd_utils_get_int(struct snd_node * node,const char * prop,int * val)44 int snd_utils_get_int(struct snd_node *node, const char *prop, int *val)
45 {
46 if (!node || !node->card_node || !node->dev_node)
47 return SND_NODE_TYPE_HW;
48
49 return node->ops->get_int(node->dev_node, prop, val);
50 }
51
snd_utils_get_str(struct snd_node * node,const char * prop,char ** val)52 int snd_utils_get_str(struct snd_node *node, const char *prop, char **val)
53 {
54 if (!node || !node->card_node || !node->dev_node)
55 return SND_NODE_TYPE_HW;
56
57 return node->ops->get_str(node->dev_node, prop, val);
58 }
59
snd_utils_close_dev_node(struct snd_node * node)60 void snd_utils_close_dev_node(struct snd_node *node)
61 {
62 if (!node)
63 return;
64
65 if (node->card_node)
66 node->ops->close_card(node->card_node);
67
68 if (node->dl_hdl)
69 dlclose(node->dl_hdl);
70
71 free(node);
72 }
73
snd_utils_get_node_type(struct snd_node * node)74 enum snd_node_type snd_utils_get_node_type(struct snd_node *node)
75 {
76 int val = SND_NODE_TYPE_HW;
77
78 if (!node || !node->card_node || !node->dev_node)
79 return SND_NODE_TYPE_HW;
80
81 node->ops->get_int(node->dev_node, "type", &val);
82
83 return val;
84 }
85
snd_utils_resolve_symbols(struct snd_node * node)86 static int snd_utils_resolve_symbols(struct snd_node *node)
87 {
88 void *dl = node->dl_hdl;
89 int err;
90 SND_DLSYM(dl, node->ops, "snd_card_ops", err);
91 return err;
92 }
93
snd_utils_open_dev_node(unsigned int card,unsigned int device,int dev_type)94 static struct snd_node *snd_utils_open_dev_node(unsigned int card,
95 unsigned int device,
96 int dev_type)
97 {
98 struct snd_node *node;
99 int rc = 0;
100
101 node = calloc(1, sizeof(*node));
102 if (!node)
103 return NULL;
104
105 node->dl_hdl = dlopen("libsndcardparser.so", RTLD_NOW);
106 if (!node->dl_hdl) {
107 goto err_dl_open;
108 }
109
110 rc = snd_utils_resolve_symbols(node);
111 if (rc < 0)
112 goto err_resolve_symbols;
113
114 node->card_node = node->ops->open_card(card);
115 if (!node->card_node)
116 goto err_resolve_symbols;
117
118 if (dev_type == NODE_PCM) {
119 node->dev_node = node->ops->get_pcm(node->card_node, device);
120 } else {
121 node->dev_node = node->ops->get_mixer(node->card_node);
122 }
123
124 if (!node->dev_node)
125 goto err_get_node;
126
127 return node;
128
129 err_get_node:
130 node->ops->close_card(node->card_node);
131
132 err_resolve_symbols:
133 dlclose(node->dl_hdl);
134
135 err_dl_open:
136 free(node);
137 return NULL;
138 }
139
snd_utils_open_pcm(unsigned int card,unsigned int device)140 struct snd_node* snd_utils_open_pcm(unsigned int card,
141 unsigned int device)
142 {
143 return snd_utils_open_dev_node(card, device, NODE_PCM);
144 }
145
snd_utils_open_mixer(unsigned int card)146 struct snd_node* snd_utils_open_mixer(unsigned int card)
147 {
148 return snd_utils_open_dev_node(card, 0, NODE_MIXER);
149 }
150