OpenTTD
extmidi.cpp
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1 /* $Id: extmidi.cpp 26556 2014-05-03 20:21:01Z rubidium $ */
2 
3 /*
4  * This file is part of OpenTTD.
5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
8  */
9 
12 #include "../stdafx.h"
13 #include "../debug.h"
14 #include "../string_func.h"
15 #include "../sound/sound_driver.hpp"
16 #include "../video/video_driver.hpp"
17 #include "../gfx_func.h"
18 #include "extmidi.h"
19 #include <fcntl.h>
20 #include <sys/types.h>
21 #include <sys/wait.h>
22 #include <unistd.h>
23 #include <signal.h>
24 #include <sys/stat.h>
25 #include <errno.h>
26 
27 #include "../safeguards.h"
28 
29 #ifndef EXTERNAL_PLAYER
30 
31 #define EXTERNAL_PLAYER "timidity"
32 #endif
33 
36 
37 const char *MusicDriver_ExtMidi::Start(const char * const * parm)
38 {
39  if (strcmp(VideoDriver::GetInstance()->GetName(), "allegro") == 0 ||
40  strcmp(SoundDriver::GetInstance()->GetName(), "allegro") == 0) {
41  return "the extmidi driver does not work when Allegro is loaded.";
42  }
43 
44  const char *command = GetDriverParam(parm, "cmd");
45  if (StrEmpty(command)) command = EXTERNAL_PLAYER;
46 
47  this->command = stredup(command);
48  this->song[0] = '\0';
49  this->pid = -1;
50  return NULL;
51 }
52 
54 {
55  free(command);
56  this->song[0] = '\0';
57  this->DoStop();
58 }
59 
60 void MusicDriver_ExtMidi::PlaySong(const char *filename)
61 {
62  strecpy(this->song, filename, lastof(this->song));
63  this->DoStop();
64 }
65 
67 {
68  this->song[0] = '\0';
69  this->DoStop();
70 }
71 
73 {
74  if (this->pid != -1 && waitpid(this->pid, NULL, WNOHANG) == this->pid) {
75  this->pid = -1;
76  }
77  if (this->pid == -1 && this->song[0] != '\0') this->DoPlay();
78  return this->pid != -1;
79 }
80 
82 {
83  DEBUG(driver, 1, "extmidi: set volume not implemented");
84 }
85 
86 void MusicDriver_ExtMidi::DoPlay()
87 {
88  this->pid = fork();
89  switch (this->pid) {
90  case 0: {
91  close(0);
92  int d = open("/dev/null", O_RDONLY);
93  if (d != -1 && dup2(d, 1) != -1 && dup2(d, 2) != -1) {
94  #if defined(MIDI_ARG)
95  execlp(this->command, "extmidi", MIDI_ARG, this->song, (char*)0);
96  #else
97  execlp(this->command, "extmidi", this->song, (char*)0);
98  #endif
99  }
100  _exit(1);
101  }
102 
103  case -1:
104  DEBUG(driver, 0, "extmidi: couldn't fork: %s", strerror(errno));
105  /* FALL THROUGH */
106 
107  default:
108  this->song[0] = '\0';
109  break;
110  }
111 }
112 
113 void MusicDriver_ExtMidi::DoStop()
114 {
115  if (this->pid <= 0) return;
116 
117  /* First try to gracefully stop for about five seconds;
118  * 5 seconds = 5000 milliseconds, 10 ms per cycle => 500 cycles. */
119  for (int i = 0; i < 500; i++) {
120  kill(this->pid, SIGTERM);
121  if (waitpid(this->pid, NULL, WNOHANG) == this->pid) {
122  /* It has shut down, so we are done */
123  this->pid = -1;
124  return;
125  }
126  /* Wait 10 milliseconds. */
127  CSleep(10);
128  }
129 
130  DEBUG(driver, 0, "extmidi: gracefully stopping failed, trying the hard way");
131  /* Gracefully stopping failed. Do it the hard way
132  * and wait till the process finally died. */
133  kill(this->pid, SIGKILL);
134  waitpid(this->pid, NULL, 0);
135  this->pid = -1;
136 }