1 /**
2 * \file control/cards.c
3 * \brief Basic Soundcard Operations
4 * \author Jaroslav Kysela <perex@perex.cz>
5 * \date 1998-2001
6 */
7 /*
8 * Soundcard Operations - main file
9 * Copyright (c) 1998 by Jaroslav Kysela <perex@perex.cz>
10 *
11 *
12 * This library is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Lesser General Public License as
14 * published by the Free Software Foundation; either version 2.1 of
15 * the License, or (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Lesser General Public License for more details.
21 *
22 * You should have received a copy of the GNU Lesser General Public
23 * License along with this library; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 *
26 */
27
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <unistd.h>
31 #include <string.h>
32 #include <ctype.h>
33 #include <fcntl.h>
34 #include <sys/ioctl.h>
35 #include "control_local.h"
36
37 #ifndef DOC_HIDDEN
38 #define SND_FILE_CONTROL ALSA_DEVICE_DIRECTORY "controlC%i"
39 #define SND_FILE_LOAD ALOAD_DEVICE_DIRECTORY "aloadC%i"
40 #endif
41
snd_card_load2(const char * control)42 static int snd_card_load2(const char *control)
43 {
44 int open_dev;
45 snd_ctl_card_info_t info;
46
47 open_dev = snd_open_device(control, O_RDONLY);
48 if (open_dev >= 0) {
49 if (ioctl(open_dev, SNDRV_CTL_IOCTL_CARD_INFO, &info) < 0) {
50 int err = -errno;
51 close(open_dev);
52 return err;
53 }
54 close(open_dev);
55 return info.card;
56 } else {
57 return -errno;
58 }
59 }
60
snd_card_load1(int card)61 static int snd_card_load1(int card)
62 {
63 int res;
64 char control[sizeof(SND_FILE_CONTROL) + 10];
65
66 sprintf(control, SND_FILE_CONTROL, card);
67 res = snd_card_load2(control);
68 #ifdef SUPPORT_ALOAD
69 if (res < 0) {
70 char aload[sizeof(SND_FILE_LOAD) + 10];
71 sprintf(aload, SND_FILE_LOAD, card);
72 res = snd_card_load2(aload);
73 }
74 #endif
75 return res;
76 }
77
78 /**
79 * \brief Try to load the driver for a card.
80 * \param card Card index.
81 * \return 1 if driver is present, zero if driver is not present.
82 */
snd_card_load(int card)83 int snd_card_load(int card)
84 {
85 return !!(snd_card_load1(card) >= 0);
86 }
87
88 /**
89 * \brief Iterate over physical sound cards.
90 *
91 * This function takes the index of a physical sound card and sets it to the
92 * index of the next card. If index is -1, it is set to the index of the first
93 * card. After the last card, the index is set to -1.
94 *
95 * For example, if you have 2 sound cards (with index 0 and 1), the index will
96 * be modified as follows:
97 *
98 * - -1 --> 0
99 * - 0 --> 1
100 * - 1 --> -1
101 *
102 * This does not work for virtual sound cards.
103 *
104 * \param rcard Index of current card. The index of the next card is stored
105 * here.
106 * \result zero if success, otherwise a negative error code.
107 */
snd_card_next(int * rcard)108 int snd_card_next(int *rcard)
109 {
110 int card;
111
112 if (rcard == NULL)
113 return -EINVAL;
114 card = *rcard;
115 card = card < 0 ? 0 : card + 1;
116 for (; card < SND_MAX_CARDS; card++) {
117 if (snd_card_load(card)) {
118 *rcard = card;
119 return 0;
120 }
121 }
122 *rcard = -1;
123 return 0;
124 }
125
126 /**
127 * \brief Convert a card string to the card index.
128 *
129 * This works only for physical sound cards, not for virtual cards.
130 *
131 * \param string A string identifying the card.
132 * \return The index of the card. On error, a a negative error code
133 * is returned.
134 *
135 * The accepted formats for "string" are:
136 * - The index of the card (as listed in /proc/asound/cards), given as string
137 * - The ID of the card (as listed in /proc/asound/cards)
138 * - The control device name (like /dev/snd/controlC0)
139 */
snd_card_get_index(const char * string)140 int snd_card_get_index(const char *string)
141 {
142 int card, err;
143 snd_ctl_t *handle;
144 snd_ctl_card_info_t info;
145
146 if (!string || *string == '\0')
147 return -EINVAL;
148 if ((isdigit(*string) && *(string + 1) == 0) ||
149 (isdigit(*string) && isdigit(*(string + 1)) && *(string + 2) == 0)) {
150 /* We got an index */
151 if (sscanf(string, "%i", &card) != 1)
152 return -EINVAL;
153 if (card < 0 || card >= SND_MAX_CARDS)
154 return -EINVAL;
155 err = snd_card_load1(card);
156 if (err >= 0)
157 return card;
158 return err;
159 }
160 if (string[0] == '/')
161 /* We got a device name */
162 return snd_card_load2(string);
163 /* We got in ID */
164 for (card = 0; card < SND_MAX_CARDS; card++) {
165 #ifdef SUPPORT_ALOAD
166 if (! snd_card_load(card))
167 continue;
168 #endif
169 if (snd_ctl_hw_open(&handle, NULL, card, 0) < 0)
170 continue;
171 if (snd_ctl_card_info(handle, &info) < 0) {
172 snd_ctl_close(handle);
173 continue;
174 }
175 snd_ctl_close(handle);
176 if (!strcmp((const char *)info.id, string))
177 return card;
178 }
179 return -ENODEV;
180 }
181
182 /**
183 * \brief Obtain the card name.
184 *
185 * \param card The index of the card.
186 * \param name Result - card name corresponding to card index.
187 * \result zero if success, otherwise a negative error code
188 *
189 * The value returned in name is allocated with strdup and should be
190 * freed when no longer used.
191 */
snd_card_get_name(int card,char ** name)192 int snd_card_get_name(int card, char **name)
193 {
194 snd_ctl_t *handle;
195 snd_ctl_card_info_t info;
196 int err;
197
198 if (name == NULL)
199 return -EINVAL;
200 if ((err = snd_ctl_hw_open(&handle, NULL, card, 0)) < 0)
201 return err;
202 if ((err = snd_ctl_card_info(handle, &info)) < 0) {
203 snd_ctl_close(handle);
204 return err;
205 }
206 snd_ctl_close(handle);
207 *name = strdup((const char *)info.name);
208 if (*name == NULL)
209 return -ENOMEM;
210 return 0;
211 }
212
213 /**
214 * \brief Obtain the card long name.
215 * \param card Index of the card.
216 * \param name Result - card long name corresponding to card index.
217 * \result Zero if success, otherwise a negative error code.
218 *
219 * The value returned in name is allocated with strdup and should be
220 * freed when no longer used.
221 */
snd_card_get_longname(int card,char ** name)222 int snd_card_get_longname(int card, char **name)
223 {
224 snd_ctl_t *handle;
225 snd_ctl_card_info_t info;
226 int err;
227
228 if (name == NULL)
229 return -EINVAL;
230 if ((err = snd_ctl_hw_open(&handle, NULL, card, 0)) < 0)
231 return err;
232 if ((err = snd_ctl_card_info(handle, &info)) < 0) {
233 snd_ctl_close(handle);
234 return err;
235 }
236 snd_ctl_close(handle);
237 *name = strdup((const char *)info.longname);
238 if (*name == NULL)
239 return -ENOMEM;
240 return 0;
241 }
242