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1 | /* |
2 | * This file is part of DisOrder |
3 | * Copyright (C) 2005, 2006, 2007 Richard Kettlewell |
4 | * |
5 | * This program is free software; you can redistribute it and/or modify |
6 | * it under the terms of the GNU General Public License as published by |
7 | * the Free Software Foundation; either version 2 of the License, or |
8 | * (at your option) any later version. |
9 | * |
10 | * This program is distributed in the hope that it will be useful, but |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | * General Public License for more details. |
14 | * |
15 | * You should have received a copy of the GNU General Public License |
16 | * along with this program; if not, write to the Free Software |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
18 | * USA |
19 | */ |
20 | /** @file server/speaker-command.c |
21 | * @brief Support for @ref BACKEND_COMMAND */ |
22 | |
23 | #include <config.h> |
24 | #include "types.h" |
25 | |
26 | #include <unistd.h> |
27 | #include <poll.h> |
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28 | #include <errno.h> |
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29 | |
30 | #include "configuration.h" |
31 | #include "syscalls.h" |
32 | #include "log.h" |
33 | #include "speaker-protocol.h" |
34 | #include "speaker.h" |
35 | |
36 | /** @brief Pipe to subprocess |
37 | * |
38 | * This is the file descriptor to write to for @ref BACKEND_COMMAND. |
39 | */ |
40 | static int cmdfd = -1; |
41 | |
42 | /** @brief poll array slot for @ref cmdfd |
43 | * |
44 | * Set by command_beforepoll(). |
45 | */ |
46 | static int cmdfd_slot; |
47 | |
48 | /** @brief Start the subprocess for @ref BACKEND_COMMAND */ |
49 | static void fork_cmd(void) { |
50 | pid_t cmdpid; |
51 | int pfd[2]; |
52 | if(cmdfd != -1) close(cmdfd); |
53 | xpipe(pfd); |
54 | cmdpid = xfork(); |
55 | if(!cmdpid) { |
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56 | exitfn = _exit; |
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57 | signal(SIGPIPE, SIG_DFL); |
58 | xdup2(pfd[0], 0); |
59 | close(pfd[0]); |
60 | close(pfd[1]); |
61 | execl("/bin/sh", "sh", "-c", config->speaker_command, (char *)0); |
62 | fatal(errno, "error execing /bin/sh"); |
63 | } |
64 | close(pfd[0]); |
65 | cmdfd = pfd[1]; |
66 | D(("forked cmd %d, fd = %d", cmdpid, cmdfd)); |
67 | } |
68 | |
69 | /** @brief Command backend initialization */ |
70 | static void command_init(void) { |
71 | info("selected command backend"); |
72 | fork_cmd(); |
73 | } |
74 | |
75 | /** @brief Play to a subprocess */ |
76 | static size_t command_play(size_t frames) { |
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77 | size_t bytes = frames * bpf; |
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78 | int written_bytes; |
79 | |
80 | written_bytes = write(cmdfd, playing->buffer + playing->start, bytes); |
81 | D(("actually play %zu bytes, wrote %d", |
82 | bytes, written_bytes)); |
83 | if(written_bytes < 0) { |
84 | switch(errno) { |
85 | case EPIPE: |
86 | error(0, "hmm, command died; trying another"); |
87 | fork_cmd(); |
88 | return 0; |
89 | case EAGAIN: |
90 | return 0; |
91 | default: |
92 | fatal(errno, "error writing to subprocess"); |
93 | } |
94 | } else |
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95 | return written_bytes / bpf; |
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96 | } |
97 | |
98 | /** @brief Update poll array for writing to subprocess */ |
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99 | static void command_beforepoll(int attribute((unused)) *timeoutp) { |
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100 | /* We send sample data to the subprocess as fast as it can accept it. |
101 | * This isn't ideal as pause latency can be very high as a result. */ |
102 | if(cmdfd >= 0) |
103 | cmdfd_slot = addfd(cmdfd, POLLOUT); |
104 | } |
105 | |
106 | /** @brief Process poll() results for subprocess play */ |
107 | static int command_ready(void) { |
108 | if(fds[cmdfd_slot].revents & (POLLOUT | POLLERR)) |
109 | return 1; |
110 | else |
111 | return 0; |
112 | } |
113 | |
114 | const struct speaker_backend command_backend = { |
115 | BACKEND_COMMAND, |
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116 | 0, |
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117 | command_init, |
118 | 0, /* activate */ |
119 | command_play, |
120 | 0, /* deactivate */ |
121 | command_beforepoll, |
122 | command_ready |
123 | }; |
124 | |
125 | /* |
126 | Local Variables: |
127 | c-basic-offset:2 |
128 | comment-column:40 |
129 | fill-column:79 |
130 | indent-tabs-mode:nil |
131 | End: |
132 | */ |