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e8c185c3 RK |
1 | /* |
2 | * This file is part of DisOrder. | |
3 | * Copyright (C) 2005, 2006, 2007, 2009 Richard Kettlewell | |
4 | * Portions (C) 2007 Mark Wooding | |
5 | * | |
6 | * This program is free software: you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation, either version 3 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | /** @file lib/uaudio-command.c | |
ec57f6c9 RK |
20 | * @brief Support for commmand backend |
21 | * | |
22 | * We use the code in @ref lib/uaudio-schedule.c to ensure that we write at | |
23 | * approximately the 'real' rate. For disorder-playrtp this isn't very useful | |
24 | * (thought it might reduce the size of various buffers downstream of us) but | |
25 | * when run from the speaker it means that pausing stands a chance of working. | |
26 | */ | |
e8c185c3 RK |
27 | #include "common.h" |
28 | ||
29 | #include <errno.h> | |
30 | #include <unistd.h> | |
31 | ||
32 | #include "syscalls.h" | |
33 | #include "log.h" | |
34 | #include "mem.h" | |
35 | #include "wstat.h" | |
36 | #include "uaudio.h" | |
ba70caca | 37 | #include "configuration.h" |
e8c185c3 RK |
38 | |
39 | /** @brief Pipe to subprocess */ | |
40 | static int command_fd; | |
41 | ||
42 | /** @brief Child process ID */ | |
43 | static pid_t command_pid; | |
44 | ||
b1f6ca8c RK |
45 | /** @brief Whether to suspend on pause */ |
46 | static int command_suspend_on_pause; | |
47 | ||
e8c185c3 RK |
48 | static const char *const command_options[] = { |
49 | "command", | |
287ad384 | 50 | "pause-mode", |
e8c185c3 RK |
51 | NULL |
52 | }; | |
53 | ||
54 | /** @brief Close pipe and wait for subprocess to terminate */ | |
55 | static void command_wait(void) { | |
56 | int w; | |
57 | pid_t rc; | |
58 | char *ws; | |
59 | ||
60 | close(command_fd); | |
61 | while((rc = waitpid(command_pid, &w, 0) < 0 && errno == EINTR)) | |
62 | ; | |
63 | if(rc < 0) | |
2e9ba080 | 64 | disorder_fatal(errno, "waitpid"); |
e8c185c3 RK |
65 | if(w) { |
66 | ws = wstat(w); | |
2e9ba080 | 67 | disorder_error(0, "command subprocess %s", ws); |
e8c185c3 RK |
68 | xfree(ws); |
69 | } | |
70 | } | |
71 | ||
72 | /** @brief Create subprocess */ | |
73 | static void command_open(void) { | |
74 | int pfd[2]; | |
75 | const char *command; | |
76 | ||
b50cfb8a | 77 | if(!(command = uaudio_get("command", NULL))) |
2e9ba080 | 78 | disorder_fatal(0, "'command' not set"); |
e8c185c3 RK |
79 | xpipe(pfd); |
80 | command_pid = xfork(); | |
81 | if(!command_pid) { | |
82 | exitfn = _exit; | |
83 | signal(SIGPIPE, SIG_DFL); | |
84 | xdup2(pfd[0], 0); | |
85 | close(pfd[0]); | |
86 | close(pfd[1]); | |
87 | /* TODO it would be nice to set some environment variables given the sample | |
88 | * format. The original intended model is that you adapt DisOrder to the | |
89 | * command you run but it'd be nice to support the opposite. */ | |
90 | execl("/bin/sh", "sh", "-c", command, (char *)0); | |
2e9ba080 | 91 | disorder_fatal(errno, "error executing /bin/sh"); |
e8c185c3 RK |
92 | } |
93 | close(pfd[0]); | |
e03eb69e | 94 | command_fd = pfd[1]; |
e8c185c3 RK |
95 | } |
96 | ||
97 | /** @brief Send audio data to subprocess */ | |
b1f6ca8c RK |
98 | static size_t command_play(void *buffer, size_t nsamples, unsigned flags) { |
99 | uaudio_schedule_sync(); | |
100 | /* If we're pausing and want that to be represented by stopping writing, we | |
101 | * just pretend */ | |
102 | if((flags & UAUDIO_PAUSED) && command_suspend_on_pause) | |
103 | return nsamples; | |
e8c185c3 RK |
104 | const size_t bytes = nsamples * uaudio_sample_size; |
105 | int written = write(command_fd, buffer, bytes); | |
106 | if(written < 0) { | |
107 | switch(errno) { | |
108 | case EINTR: | |
109 | return 0; /* will retry */ | |
110 | case EPIPE: | |
2e9ba080 | 111 | disorder_error(0, "audio command subprocess terminated"); |
e8c185c3 RK |
112 | command_wait(); |
113 | command_open(); | |
114 | return 0; /* will retry */ | |
115 | default: | |
2e9ba080 | 116 | disorder_fatal(errno, "error writing to audio command subprocess"); |
e8c185c3 RK |
117 | } |
118 | } | |
b1f6ca8c RK |
119 | /* TODO what if we write a partial sample? Actually reasonably unlikely but |
120 | * not impossible. Maybe someone who actually uses this backend should sort | |
121 | * it out. */ | |
ec57f6c9 | 122 | const size_t written_samples = written / uaudio_sample_size; |
b1f6ca8c | 123 | uaudio_schedule_sent(written_samples); |
ec57f6c9 | 124 | return written_samples; |
e8c185c3 RK |
125 | } |
126 | ||
127 | static void command_start(uaudio_callback *callback, | |
128 | void *userdata) { | |
287ad384 RK |
129 | const char *pausemode = uaudio_get("pause-mode", "silence"); |
130 | unsigned flags = 0; | |
131 | ||
132 | if(!strcmp(pausemode, "silence")) | |
b1f6ca8c | 133 | command_suspend_on_pause = 0; |
287ad384 | 134 | else if(!strcmp(pausemode, "suspend")) |
b1f6ca8c | 135 | command_suspend_on_pause = 1; |
287ad384 | 136 | else |
2e9ba080 | 137 | disorder_fatal(0, "unknown pause mode '%s'", pausemode); |
e8c185c3 | 138 | command_open(); |
ec57f6c9 | 139 | uaudio_schedule_init(); |
e8c185c3 RK |
140 | uaudio_thread_start(callback, |
141 | userdata, | |
142 | command_play, | |
143 | uaudio_channels, | |
63761c19 | 144 | 4096 / uaudio_sample_size, |
287ad384 | 145 | flags); |
e8c185c3 RK |
146 | } |
147 | ||
148 | static void command_stop(void) { | |
149 | uaudio_thread_stop(); | |
150 | command_wait(); | |
151 | } | |
152 | ||
ba70caca RK |
153 | static void command_configure(void) { |
154 | uaudio_set("command", config->speaker_command); | |
f75ab9d3 | 155 | uaudio_set("pause-mode", config->pause_mode); |
ba70caca RK |
156 | } |
157 | ||
e8c185c3 RK |
158 | const struct uaudio uaudio_command = { |
159 | .name = "command", | |
160 | .options = command_options, | |
161 | .start = command_start, | |
162 | .stop = command_stop, | |
b1f6ca8c RK |
163 | .activate = uaudio_thread_activate, |
164 | .deactivate = uaudio_thread_deactivate, | |
ba70caca | 165 | .configure = command_configure, |
e8c185c3 RK |
166 | }; |
167 | ||
168 | /* | |
169 | Local Variables: | |
170 | c-basic-offset:2 | |
171 | comment-column:40 | |
172 | fill-column:79 | |
173 | indent-tabs-mode:nil | |
174 | End: | |
175 | */ |