src/music/extmidi.cpp

   1 /* $Id$ */
   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
  10 /** @file extmidi.cpp Playing music via an external player. */
  11
  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 /** The default external midi player. */
  31 #define EXTERNAL_PLAYER "timidity"
  32 #endif
  33
  34 /** Factory for the midi player that uses external players. */
  35 static FMusicDriver_ExtMidi iFMusicDriver_ExtMidi;
  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
  53 void MusicDriver_ExtMidi::Stop()
  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
  66 void MusicDriver_ExtMidi::StopSong()
  67 {
  68         this->song[0] = '\0';
  69         this->DoStop();
  70 }
  71
  72 bool MusicDriver_ExtMidi::IsSongPlaying()
  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
  81 void MusicDriver_ExtMidi::SetVolume(byte vol)
  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 }