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 "../core/alloc_func.hpp"
  16 #include "../sound/sound_driver.hpp"
  17 #include "../video/video_driver.hpp"
  18 #include "../gfx_func.h"
  19 #include "extmidi.h"
  20 #include <fcntl.h>
  21 #include <sys/types.h>
  22 #include <sys/wait.h>
  23 #include <unistd.h>
  24 #include <signal.h>
  25 #include <sys/stat.h>
  26 #include <errno.h>
  27
  28 #include "../safeguards.h"
  29
  30 #ifndef EXTERNAL_PLAYER
  31 /** The default external midi player. */
  32 #define EXTERNAL_PLAYER "timidity"
  33 #endif
  34
  35 /** Factory for the midi player that uses external players. */
  36 static FMusicDriver_ExtMidi iFMusicDriver_ExtMidi;
  37
  38 const char *MusicDriver_ExtMidi::Start(const char * const * parm)
  39 {
  40         if (strcmp(VideoDriver::GetInstance()->GetName(), "allegro") == 0 ||
  41                         strcmp(SoundDriver::GetInstance()->GetName(), "allegro") == 0) {
  42                 return "the extmidi driver does not work when Allegro is loaded.";
  43         }
  44
  45         const char *command = GetDriverParam(parm, "cmd");
  46 #ifndef MIDI_ARG
  47         if (StrEmpty(command)) command = EXTERNAL_PLAYER;
  48 #else
  49         if (StrEmpty(command)) command = EXTERNAL_PLAYER " " MIDI_ARG;
  50 #endif
  51
  52         /* Count number of arguments, but include 3 extra slots: 1st for command, 2nd for song title, and 3rd for terminating NULL. */
  53         uint num_args = 3;
  54         for (const char *t = command; *t != '\0'; t++) if (*t == ' ') num_args++;
  55
  56         this->params = CallocT<char *>(num_args);
  57         this->params[0] = stredup(command);
  58
  59         /* Replace space with \0 and add next arg to params */
  60         uint p = 1;
  61         while (true) {
  62                 this->params[p] = strchr(this->params[p - 1], ' ');
  63                 if (this->params[p] == NULL) break;
  64
  65                 this->params[p][0] = '\0';
  66                 this->params[p]++;
  67                 p++;
  68         }
  69
  70         /* Last parameter is the song file. */
  71         this->params[p] = this->song;
  72
  73         this->song[0] = '\0';
  74         this->pid = -1;
  75         return NULL;
  76 }
  77
  78 void MusicDriver_ExtMidi::Stop()
  79 {
  80         free(params[0]);
  81         free(params);
  82         this->song[0] = '\0';
  83         this->DoStop();
  84 }
  85
  86 void MusicDriver_ExtMidi::PlaySong(const char *filename)
  87 {
  88         strecpy(this->song, filename, lastof(this->song));
  89         this->DoStop();
  90 }
  91
  92 void MusicDriver_ExtMidi::StopSong()
  93 {
  94         this->song[0] = '\0';
  95         this->DoStop();
  96 }
  97
  98 bool MusicDriver_ExtMidi::IsSongPlaying()
  99 {
 100         if (this->pid != -1 && waitpid(this->pid, NULL, WNOHANG) == this->pid) {
 101                 this->pid = -1;
 102         }
 103         if (this->pid == -1 && this->song[0] != '\0') this->DoPlay();
 104         return this->pid != -1;
 105 }
 106
 107 void MusicDriver_ExtMidi::SetVolume(byte vol)
 108 {
 109         DEBUG(driver, 1, "extmidi: set volume not implemented");
 110 }
 111
 112 void MusicDriver_ExtMidi::DoPlay()
 113 {
 114         this->pid = fork();
 115         switch (this->pid) {
 116                 case 0: {
 117                         close(0);
 118                         int d = open("/dev/null", O_RDONLY);
 119                         if (d != -1 && dup2(d, 1) != -1 && dup2(d, 2) != -1) {
 120                                 execvp(this->params[0], this->params);
 121                         }
 122                         _exit(1);
 123                 }
 124
 125                 case -1:
 126                         DEBUG(driver, 0, "extmidi: couldn't fork: %s", strerror(errno));
 127                         FALLTHROUGH;
 128
 129                 default:
 130                         this->song[0] = '\0';
 131                         break;
 132         }
 133 }
 134
 135 void MusicDriver_ExtMidi::DoStop()
 136 {
 137         if (this->pid <= 0) return;
 138
 139         /* First try to gracefully stop for about five seconds;
 140          * 5 seconds = 5000 milliseconds, 10 ms per cycle => 500 cycles. */
 141         for (int i = 0; i < 500; i++) {
 142                 kill(this->pid, SIGTERM);
 143                 if (waitpid(this->pid, NULL, WNOHANG) == this->pid) {
 144                         /* It has shut down, so we are done */
 145                         this->pid = -1;
 146                         return;
 147                 }
 148                 /* Wait 10 milliseconds. */
 149                 CSleep(10);
 150         }
 151
 152         DEBUG(driver, 0, "extmidi: gracefully stopping failed, trying the hard way");
 153         /* Gracefully stopping failed. Do it the hard way
 154          * and wait till the process finally died. */
 155         kill(this->pid, SIGKILL);
 156         waitpid(this->pid, NULL, 0);
 157         this->pid = -1;
 158 }