1 /*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20 */
21 #include "../SDL_internal.h"
22
23 /* Get the name of the audio device we use for output */
24
25 #if SDL_AUDIO_DRIVER_NETBSD || SDL_AUDIO_DRIVER_OSS || SDL_AUDIO_DRIVER_SUNAUDIO
26
27 #include <fcntl.h>
28 #include <sys/types.h>
29 #include <sys/stat.h>
30 #include <unistd.h> /* For close() */
31
32 #include "SDL_stdinc.h"
33 #include "SDL_audiodev_c.h"
34
35 #ifndef _PATH_DEV_DSP
36 #if defined(__NETBSD__) || defined(__OPENBSD__)
37 #define _PATH_DEV_DSP "/dev/audio"
38 #else
39 #define _PATH_DEV_DSP "/dev/dsp"
40 #endif
41 #endif
42 #ifndef _PATH_DEV_DSP24
43 #define _PATH_DEV_DSP24 "/dev/sound/dsp"
44 #endif
45 #ifndef _PATH_DEV_AUDIO
46 #define _PATH_DEV_AUDIO "/dev/audio"
47 #endif
48
49 static void
test_device(const int iscapture,const char * fname,int flags,int (* test)(int fd))50 test_device(const int iscapture, const char *fname, int flags, int (*test) (int fd))
51 {
52 struct stat sb;
53 if ((stat(fname, &sb) == 0) && (S_ISCHR(sb.st_mode))) {
54 const int audio_fd = open(fname, flags | O_CLOEXEC, 0);
55 if (audio_fd >= 0) {
56 const int okay = test(audio_fd);
57 close(audio_fd);
58 if (okay) {
59 static size_t dummyhandle = 0;
60 dummyhandle++;
61 SDL_assert(dummyhandle != 0);
62
63 /* Note that spec is NULL; while we are opening the device
64 * endpoint here, the endpoint does not provide any mix format
65 * information, making this information inaccessible at
66 * enumeration time
67 */
68 SDL_AddAudioDevice(iscapture, fname, NULL, (void *) (uintptr_t) dummyhandle);
69 }
70 }
71 }
72 }
73
74 static int
test_stub(int fd)75 test_stub(int fd)
76 {
77 return 1;
78 }
79
80 static void
SDL_EnumUnixAudioDevices_Internal(const int iscapture,const int classic,int (* test)(int))81 SDL_EnumUnixAudioDevices_Internal(const int iscapture, const int classic, int (*test)(int))
82 {
83 const int flags = iscapture ? OPEN_FLAGS_INPUT : OPEN_FLAGS_OUTPUT;
84 const char *audiodev;
85 char audiopath[1024];
86
87 if (test == NULL)
88 test = test_stub;
89
90 /* Figure out what our audio device is */
91 if (((audiodev = SDL_getenv("SDL_PATH_DSP")) == NULL) &&
92 ((audiodev = SDL_getenv("AUDIODEV")) == NULL)) {
93 if (classic) {
94 audiodev = _PATH_DEV_AUDIO;
95 } else {
96 struct stat sb;
97
98 /* Added support for /dev/sound/\* in Linux 2.4 */
99 if (((stat("/dev/sound", &sb) == 0) && S_ISDIR(sb.st_mode))
100 && ((stat(_PATH_DEV_DSP24, &sb) == 0)
101 && S_ISCHR(sb.st_mode))) {
102 audiodev = _PATH_DEV_DSP24;
103 } else {
104 audiodev = _PATH_DEV_DSP;
105 }
106 }
107 }
108 test_device(iscapture, audiodev, flags, test);
109
110 if (SDL_strlen(audiodev) < (sizeof(audiopath) - 3)) {
111 int instance = 0;
112 while (instance <= 64) {
113 SDL_snprintf(audiopath, SDL_arraysize(audiopath),
114 "%s%d", audiodev, instance);
115 instance++;
116 test_device(iscapture, audiopath, flags, test);
117 }
118 }
119 }
120
121 void
SDL_EnumUnixAudioDevices(const int classic,int (* test)(int))122 SDL_EnumUnixAudioDevices(const int classic, int (*test)(int))
123 {
124 SDL_EnumUnixAudioDevices_Internal(SDL_TRUE, classic, test);
125 SDL_EnumUnixAudioDevices_Internal(SDL_FALSE, classic, test);
126 }
127
128 #endif /* Audio driver selection */
129
130 /* vi: set ts=4 sw=4 expandtab: */
131