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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" | |
37 | ||
38 | /** @brief Pipe to subprocess */ | |
39 | static int command_fd; | |
40 | ||
41 | /** @brief Child process ID */ | |
42 | static pid_t command_pid; | |
43 | ||
44 | static const char *const command_options[] = { | |
45 | "command", | |
46 | NULL | |
47 | }; | |
48 | ||
49 | /** @brief Close pipe and wait for subprocess to terminate */ | |
50 | static void command_wait(void) { | |
51 | int w; | |
52 | pid_t rc; | |
53 | char *ws; | |
54 | ||
55 | close(command_fd); | |
56 | while((rc = waitpid(command_pid, &w, 0) < 0 && errno == EINTR)) | |
57 | ; | |
58 | if(rc < 0) | |
59 | fatal(errno, "waitpid"); | |
60 | if(w) { | |
61 | ws = wstat(w); | |
62 | error(0, "command subprocess %s", ws); | |
63 | xfree(ws); | |
64 | } | |
65 | } | |
66 | ||
67 | /** @brief Create subprocess */ | |
68 | static void command_open(void) { | |
69 | int pfd[2]; | |
70 | const char *command; | |
71 | ||
72 | if(!(command = uaudio_get("command"))) | |
73 | fatal(0, "'command' not set"); | |
74 | xpipe(pfd); | |
75 | command_pid = xfork(); | |
76 | if(!command_pid) { | |
77 | exitfn = _exit; | |
78 | signal(SIGPIPE, SIG_DFL); | |
79 | xdup2(pfd[0], 0); | |
80 | close(pfd[0]); | |
81 | close(pfd[1]); | |
82 | /* TODO it would be nice to set some environment variables given the sample | |
83 | * format. The original intended model is that you adapt DisOrder to the | |
84 | * command you run but it'd be nice to support the opposite. */ | |
85 | execl("/bin/sh", "sh", "-c", command, (char *)0); | |
86 | fatal(errno, "error executing /bin/sh"); | |
87 | } | |
88 | close(pfd[0]); | |
e03eb69e | 89 | command_fd = pfd[1]; |
e8c185c3 RK |
90 | } |
91 | ||
92 | /** @brief Send audio data to subprocess */ | |
93 | static size_t command_play(void *buffer, size_t nsamples) { | |
ec57f6c9 | 94 | uaudio_schedule_synchronize(); |
e8c185c3 RK |
95 | const size_t bytes = nsamples * uaudio_sample_size; |
96 | int written = write(command_fd, buffer, bytes); | |
97 | if(written < 0) { | |
98 | switch(errno) { | |
99 | case EINTR: | |
100 | return 0; /* will retry */ | |
101 | case EPIPE: | |
102 | error(0, "audio command subprocess terminated"); | |
103 | command_wait(); | |
104 | command_open(); | |
105 | return 0; /* will retry */ | |
106 | default: | |
107 | fatal(errno, "error writing to audio command subprocess"); | |
108 | } | |
109 | } | |
ec57f6c9 RK |
110 | const size_t written_samples = written / uaudio_sample_size; |
111 | uaudio_schedule_update(written_samples); | |
112 | return written_samples; | |
e8c185c3 RK |
113 | } |
114 | ||
115 | static void command_start(uaudio_callback *callback, | |
116 | void *userdata) { | |
117 | command_open(); | |
ec57f6c9 | 118 | uaudio_schedule_init(); |
e8c185c3 RK |
119 | uaudio_thread_start(callback, |
120 | userdata, | |
121 | command_play, | |
122 | uaudio_channels, | |
123 | 4096 / uaudio_sample_size); | |
124 | } | |
125 | ||
126 | static void command_stop(void) { | |
127 | uaudio_thread_stop(); | |
128 | command_wait(); | |
129 | } | |
130 | ||
131 | static void command_activate(void) { | |
ec57f6c9 | 132 | uaudio_schedule_reactivated = 1; |
e8c185c3 RK |
133 | uaudio_thread_activate(); |
134 | } | |
135 | ||
136 | static void command_deactivate(void) { | |
137 | uaudio_thread_deactivate(); | |
138 | } | |
139 | ||
140 | const struct uaudio uaudio_command = { | |
141 | .name = "command", | |
142 | .options = command_options, | |
143 | .start = command_start, | |
144 | .stop = command_stop, | |
145 | .activate = command_activate, | |
146 | .deactivate = command_deactivate | |
147 | }; | |
148 | ||
149 | /* | |
150 | Local Variables: | |
151 | c-basic-offset:2 | |
152 | comment-column:40 | |
153 | fill-column:79 | |
154 | indent-tabs-mode:nil | |
155 | End: | |
156 | */ |