src/cdrom/linux/SDL_syscdrom.c - third_party/sdl - Git at Google

 /*
     SDL - Simple DirectMedia Layer
     Copyright (C) 1997-2009 Sam Lantinga

     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.

     This library 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.  See the GNU
     Lesser General Public License for more details.

     You should have received a copy of the GNU Lesser General Public
     License along with this library; if not, write to the Free Software
     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

     Sam Lantinga
     slouken@libsdl.org
 */
 #include "SDL_config.h"

 #ifdef SDL_CDROM_LINUX

 /* Functions for system-level CD-ROM audio control */

 #include <string.h>	/* For strerror() */
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/ioctl.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <unistd.h>
 #ifdef __LINUX__
 #ifdef HAVE_LINUX_VERSION_H
 /* linux 2.6.9 workaround */
 #include <linux/version.h>
 #if LINUX_VERSION_CODE == KERNEL_VERSION(2,6,9)
 #include <asm/types.h>
 #define __le64 __u64
 #define __le32 __u32
 #define __le16 __u16
 #define __be64 __u64
 #define __be32 __u32
 #define __be16 __u16
 #endif /* linux 2.6.9 workaround */
 #endif /* HAVE_LINUX_VERSION_H */
 #include <linux/cdrom.h>
 #endif
 #ifdef __SVR4
 #include <sys/cdio.h>
 #endif

 /* Define this to use the alternative getmntent() code */
 #ifndef __SVR4
 #define USE_MNTENT
 #endif

 #ifdef USE_MNTENT
 #if defined(__USLC__)
 #include <sys/mntent.h>
 #else
 #include <mntent.h>
 #endif

 #ifndef _PATH_MNTTAB
 #ifdef MNTTAB
 #define _PATH_MNTTAB	MNTTAB
 #else
 #define _PATH_MNTTAB	"/etc/fstab"
 #endif
 #endif /* !_PATH_MNTTAB */

 #ifndef _PATH_MOUNTED
 #define _PATH_MOUNTED	"/etc/mtab"
 #endif /* !_PATH_MOUNTED */

 #ifndef MNTTYPE_CDROM
 #define MNTTYPE_CDROM	"iso9660"
 #endif
 #ifndef MNTTYPE_SUPER
 #define MNTTYPE_SUPER	"supermount"
 #endif
 #endif /* USE_MNTENT */

 #include "SDL_cdrom.h"
 #include "../SDL_syscdrom.h"


 /* The maximum number of CD-ROM drives we'll detect */
 #define MAX_DRIVES	16

 /* A list of available CD-ROM drives */
 static char *SDL_cdlist[MAX_DRIVES];
 static dev_t SDL_cdmode[MAX_DRIVES];

 /* The system-dependent CD control functions */
 static const char *SDL_SYS_CDName(int drive);
 static int SDL_SYS_CDOpen(int drive);
 static int SDL_SYS_CDGetTOC(SDL_CD *cdrom);
 static CDstatus SDL_SYS_CDStatus(SDL_CD *cdrom, int *position);
 static int SDL_SYS_CDPlay(SDL_CD *cdrom, int start, int length);
 static int SDL_SYS_CDPause(SDL_CD *cdrom);
 static int SDL_SYS_CDResume(SDL_CD *cdrom);
 static int SDL_SYS_CDStop(SDL_CD *cdrom);
 static int SDL_SYS_CDEject(SDL_CD *cdrom);
 static void SDL_SYS_CDClose(SDL_CD *cdrom);

 /* Some ioctl() errno values which occur when the tray is empty */
 #ifndef ENOMEDIUM
 #define ENOMEDIUM ENOENT
 #endif
 #define ERRNO_TRAYEMPTY(errno)	\
 	((errno == EIO)    || (errno == ENOENT) || \
 	 (errno == EINVAL) || (errno == ENOMEDIUM))

 /* Check a drive to see if it is a CD-ROM */
 static int CheckDrive(char *drive, char *mnttype, struct stat *stbuf)
 {
 	int is_cd, cdfd;
 	struct cdrom_subchnl info;

 	/* If it doesn't exist, return -1 */
 	if ( stat(drive, stbuf) < 0 ) {
 		return(-1);
 	}

 	/* If it does exist, verify that it's an available CD-ROM */
 	is_cd = 0;
 	if ( S_ISCHR(stbuf->st_mode) || S_ISBLK(stbuf->st_mode) ) {
 		cdfd = open(drive, (O_RDONLY|O_NONBLOCK), 0);
 		if ( cdfd >= 0 ) {
 			info.cdsc_format = CDROM_MSF;
 			/* Under Linux, EIO occurs when a disk is not present.
 			 */
 			if ( (ioctl(cdfd, CDROMSUBCHNL, &info) == 0) ||
 						ERRNO_TRAYEMPTY(errno) ) {
 				is_cd = 1;
 			}
 			close(cdfd);
 		}
 #ifdef USE_MNTENT
 		/* Even if we can't read it, it might be mounted */
 		else if ( mnttype && (SDL_strcmp(mnttype, MNTTYPE_CDROM) == 0) ) {
 			is_cd = 1;
 		}
 #endif
 	}
 	return(is_cd);
 }

 /* Add a CD-ROM drive to our list of valid drives */
 static void AddDrive(char *drive, struct stat *stbuf)
 {
 	int i;

 	if ( SDL_numcds < MAX_DRIVES ) {
 		/* Check to make sure it's not already in our list.
 	 	   This can happen when we see a drive via symbolic link.
 		 */
 		for ( i=0; i<SDL_numcds; ++i ) {
 			if ( stbuf->st_rdev == SDL_cdmode[i] ) {
 #ifdef DEBUG_CDROM
   fprintf(stderr, "Duplicate drive detected: %s == %s\n", drive, SDL_cdlist[i]);
 #endif
 				return;
 			}
 		}

 		/* Add this drive to our list */
 		i = SDL_numcds;
 		SDL_cdlist[i] = SDL_strdup(drive);
 		if ( SDL_cdlist[i] == NULL ) {
 			SDL_OutOfMemory();
 			return;
 		}
 		SDL_cdmode[i] = stbuf->st_rdev;
 		++SDL_numcds;
 #ifdef DEBUG_CDROM
   fprintf(stderr, "Added CD-ROM drive: %s\n", drive);
 #endif
 	}
 }

 #ifdef USE_MNTENT
 static void CheckMounts(const char *mtab)
 {
 	FILE *mntfp;
 	struct mntent *mntent;
 	struct stat stbuf;

 	mntfp = setmntent(mtab, "r");
 	if ( mntfp != NULL ) {
 		char *tmp;
 		char *mnt_type;
 		size_t mnt_type_len;
 		char *mnt_dev;
 		size_t mnt_dev_len;

 		while ( (mntent=getmntent(mntfp)) != NULL ) {
 			mnt_type_len = SDL_strlen(mntent->mnt_type) + 1;
 			mnt_type = SDL_stack_alloc(char, mnt_type_len);
 			if (mnt_type == NULL)
 				continue;  /* maybe you'll get lucky next time. */

 			mnt_dev_len = SDL_strlen(mntent->mnt_fsname) + 1;
 			mnt_dev = SDL_stack_alloc(char, mnt_dev_len);
 			if (mnt_dev == NULL) {
 				SDL_stack_free(mnt_type);
 				continue;
 			}

 			SDL_strlcpy(mnt_type, mntent->mnt_type, mnt_type_len);
 			SDL_strlcpy(mnt_dev, mntent->mnt_fsname, mnt_dev_len);

 			/* Handle "supermount" filesystem mounts */
 			if ( SDL_strcmp(mnt_type, MNTTYPE_SUPER) == 0 ) {
 				tmp = SDL_strstr(mntent->mnt_opts, "fs=");
 				if ( tmp ) {
 					SDL_stack_free(mnt_type);
 					mnt_type = SDL_strdup(tmp + SDL_strlen("fs="));
 					if ( mnt_type ) {
 						tmp = SDL_strchr(mnt_type, ',');
 						if ( tmp ) {
 							*tmp = '\0';
 						}
 					}
 				}
 				tmp = SDL_strstr(mntent->mnt_opts, "dev=");
 				if ( tmp ) {
 					SDL_stack_free(mnt_dev);
 					mnt_dev = SDL_strdup(tmp + SDL_strlen("dev="));
 					if ( mnt_dev ) {
 						tmp = SDL_strchr(mnt_dev, ',');
 						if ( tmp ) {
 							*tmp = '\0';
 						}
 					}
 				}
 			}
 			if ( SDL_strcmp(mnt_type, MNTTYPE_CDROM) == 0 ) {
 #ifdef DEBUG_CDROM
   fprintf(stderr, "Checking mount path from %s: %s mounted on %s of %s\n",
 	mtab, mnt_dev, mntent->mnt_dir, mnt_type);
 #endif
 				if (CheckDrive(mnt_dev, mnt_type, &stbuf) > 0) {
 					AddDrive(mnt_dev, &stbuf);
 				}
 			}
 			SDL_stack_free(mnt_dev);
 			SDL_stack_free(mnt_type);
 		}
 		endmntent(mntfp);
 	}
 }
 #endif /* USE_MNTENT */

 int  SDL_SYS_CDInit(void)
 {
 	/* checklist: /dev/cdrom, /dev/hd?, /dev/scd? /dev/sr? */
 	static char *checklist[] = {
 		"cdrom", "?a hd?", "?0 scd?", "?0 sr?", NULL
 	};
 	char *SDLcdrom;
 	int i, j, exists;
 	char drive[32];
 	struct stat stbuf;

 	/* Fill in our driver capabilities */
 	SDL_CDcaps.Name = SDL_SYS_CDName;
 	SDL_CDcaps.Open = SDL_SYS_CDOpen;
 	SDL_CDcaps.GetTOC = SDL_SYS_CDGetTOC;
 	SDL_CDcaps.Status = SDL_SYS_CDStatus;
 	SDL_CDcaps.Play = SDL_SYS_CDPlay;
 	SDL_CDcaps.Pause = SDL_SYS_CDPause;
 	SDL_CDcaps.Resume = SDL_SYS_CDResume;
 	SDL_CDcaps.Stop = SDL_SYS_CDStop;
 	SDL_CDcaps.Eject = SDL_SYS_CDEject;
 	SDL_CDcaps.Close = SDL_SYS_CDClose;

 	/* Look in the environment for our CD-ROM drive list */
 	SDLcdrom = SDL_getenv("SDL_CDROM");	/* ':' separated list of devices */
 	if ( SDLcdrom != NULL ) {
 		char *cdpath, *delim;
 		size_t len = SDL_strlen(SDLcdrom)+1;
 		cdpath = SDL_stack_alloc(char, len);
 		if ( cdpath != NULL ) {
 			SDL_strlcpy(cdpath, SDLcdrom, len);
 			SDLcdrom = cdpath;
 			do {
 				delim = SDL_strchr(SDLcdrom, ':');
 				if ( delim ) {
 					*delim++ = '\0';
 				}
 #ifdef DEBUG_CDROM
   fprintf(stderr, "Checking CD-ROM drive from SDL_CDROM: %s\n", SDLcdrom);
 #endif
 				if ( CheckDrive(SDLcdrom, NULL, &stbuf) > 0 ) {
 					AddDrive(SDLcdrom, &stbuf);
 				}
 				if ( delim ) {
 					SDLcdrom = delim;
 				} else {
 					SDLcdrom = NULL;
 				}
 			} while ( SDLcdrom );
 			SDL_stack_free(cdpath);
 		}

 		/* If we found our drives, there's nothing left to do */
 		if ( SDL_numcds > 0 ) {
 			return(0);
 		}
 	}

 #ifdef USE_MNTENT
 	/* Check /dev/cdrom first :-) */
 	if (CheckDrive("/dev/cdrom", NULL, &stbuf) > 0) {
 		AddDrive("/dev/cdrom", &stbuf);
 	}

 	/* Now check the currently mounted CD drives */
 	CheckMounts(_PATH_MOUNTED);

 	/* Finally check possible mountable drives in /etc/fstab */
 	CheckMounts(_PATH_MNTTAB);

 	/* If we found our drives, there's nothing left to do */
 	if ( SDL_numcds > 0 ) {
 		return(0);
 	}
 #endif /* USE_MNTENT */

 	/* Scan the system for CD-ROM drives.
 	   Not always 100% reliable, so use the USE_MNTENT code above first.
 	 */
 	for ( i=0; checklist[i]; ++i ) {
 		if ( checklist[i][0] == '?' ) {
 			char *insert;
 			exists = 1;
 			for ( j=checklist[i][1]; exists; ++j ) {
 				SDL_snprintf(drive, SDL_arraysize(drive), "/dev/%s", &checklist[i][3]);
 				insert = SDL_strchr(drive, '?');
 				if ( insert != NULL ) {
 					*insert = j;
 				}
 #ifdef DEBUG_CDROM
   fprintf(stderr, "Checking possible CD-ROM drive: %s\n", drive);
 #endif
 				switch (CheckDrive(drive, NULL, &stbuf)) {
 					/* Drive exists and is a CD-ROM */
 					case 1:
 						AddDrive(drive, &stbuf);
 						break;
 					/* Drive exists, but isn't a CD-ROM */
 					case 0:
 						break;
 					/* Drive doesn't exist */
 					case -1:
 						exists = 0;
 						break;
 				}
 			}
 		} else {
 			SDL_snprintf(drive, SDL_arraysize(drive), "/dev/%s", checklist[i]);
 #ifdef DEBUG_CDROM
   fprintf(stderr, "Checking possible CD-ROM drive: %s\n", drive);
 #endif
 			if ( CheckDrive(drive, NULL, &stbuf) > 0 ) {
 				AddDrive(drive, &stbuf);
 			}
 		}
 	}
 	return(0);
 }

 /* General ioctl() CD-ROM command function */
 static int SDL_SYS_CDioctl(int id, int command, void *arg)
 {
 	int retval;

 	retval = ioctl(id, command, arg);
 	if ( retval < 0 ) {
 		SDL_SetError("ioctl() error: %s", strerror(errno));
 	}
 	return(retval);
 }

 static const char *SDL_SYS_CDName(int drive)
 {
 	return(SDL_cdlist[drive]);
 }

 static int SDL_SYS_CDOpen(int drive)
 {
 	return(open(SDL_cdlist[drive], (O_RDONLY|O_NONBLOCK), 0));
 }

 static int SDL_SYS_CDGetTOC(SDL_CD *cdrom)
 {
 	struct cdrom_tochdr toc;
 	int i, okay;
 	struct cdrom_tocentry entry;

 	okay = 0;
 	if ( SDL_SYS_CDioctl(cdrom->id, CDROMREADTOCHDR, &toc) == 0 ) {
 		cdrom->numtracks = toc.cdth_trk1-toc.cdth_trk0+1;
 		if ( cdrom->numtracks > SDL_MAX_TRACKS ) {
 			cdrom->numtracks = SDL_MAX_TRACKS;
 		}
 		/* Read all the track TOC entries */
 		for ( i=0; i<=cdrom->numtracks; ++i ) {
 			if ( i == cdrom->numtracks ) {
 				cdrom->track[i].id = CDROM_LEADOUT;
 			} else {
 				cdrom->track[i].id = toc.cdth_trk0+i;
 			}
 			entry.cdte_track = cdrom->track[i].id;
 			entry.cdte_format = CDROM_MSF;
 			if ( SDL_SYS_CDioctl(cdrom->id, CDROMREADTOCENTRY,
 								&entry) < 0 ) {
 				break;
 			} else {
 				if ( entry.cdte_ctrl & CDROM_DATA_TRACK ) {
 					cdrom->track[i].type = SDL_DATA_TRACK;
 				} else {
 					cdrom->track[i].type = SDL_AUDIO_TRACK;
 				}
 				cdrom->track[i].offset = MSF_TO_FRAMES(
 						entry.cdte_addr.msf.minute,
 						entry.cdte_addr.msf.second,
 						entry.cdte_addr.msf.frame);
 				cdrom->track[i].length = 0;
 				if ( i > 0 ) {
 					cdrom->track[i-1].length =
 						cdrom->track[i].offset-
 						cdrom->track[i-1].offset;
 				}
 			}
 		}
 		if ( i == (cdrom->numtracks+1) ) {
 			okay = 1;
 		}
 	}
 	return(okay ? 0 : -1);
 }

 /* Get CD-ROM status */
 static CDstatus SDL_SYS_CDStatus(SDL_CD *cdrom, int *position)
 {
 	CDstatus status;
 	struct cdrom_tochdr toc;
 	struct cdrom_subchnl info;

 	info.cdsc_format = CDROM_MSF;
 	if ( ioctl(cdrom->id, CDROMSUBCHNL, &info) < 0 ) {
 		if ( ERRNO_TRAYEMPTY(errno) ) {
 			status = CD_TRAYEMPTY;
 		} else {
 			status = CD_ERROR;
 		}
 	} else {
 		switch (info.cdsc_audiostatus) {
 			case CDROM_AUDIO_INVALID:
 			case CDROM_AUDIO_NO_STATUS:
 				/* Try to determine if there's a CD available */
 				if (ioctl(cdrom->id, CDROMREADTOCHDR, &toc)==0)
 					status = CD_STOPPED;
 				else
 					status = CD_TRAYEMPTY;
 				break;
 			case CDROM_AUDIO_COMPLETED:
 				status = CD_STOPPED;
 				break;
 			case CDROM_AUDIO_PLAY:
 				status = CD_PLAYING;
 				break;
 			case CDROM_AUDIO_PAUSED:
 				/* Workaround buggy CD-ROM drive */
 				if ( info.cdsc_trk == CDROM_LEADOUT ) {
 					status = CD_STOPPED;
 				} else {
 					status = CD_PAUSED;
 				}
 				break;
 			default:
 				status = CD_ERROR;
 				break;
 		}
 	}
 	if ( position ) {
 		if ( status == CD_PLAYING || (status == CD_PAUSED) ) {
 			*position = MSF_TO_FRAMES(
 					info.cdsc_absaddr.msf.minute,
 					info.cdsc_absaddr.msf.second,
 					info.cdsc_absaddr.msf.frame);
 		} else {
 			*position = 0;
 		}
 	}
 	return(status);
 }

 /* Start play */
 static int SDL_SYS_CDPlay(SDL_CD *cdrom, int start, int length)
 {
 	struct cdrom_msf playtime;

 	FRAMES_TO_MSF(start,
 	   &playtime.cdmsf_min0, &playtime.cdmsf_sec0, &playtime.cdmsf_frame0);
 	FRAMES_TO_MSF(start+length,
 	   &playtime.cdmsf_min1, &playtime.cdmsf_sec1, &playtime.cdmsf_frame1);
 #ifdef DEBUG_CDROM
   fprintf(stderr, "Trying to play from %d:%d:%d to %d:%d:%d\n",
 	playtime.cdmsf_min0, playtime.cdmsf_sec0, playtime.cdmsf_frame0,
 	playtime.cdmsf_min1, playtime.cdmsf_sec1, playtime.cdmsf_frame1);
 #endif
 	return(SDL_SYS_CDioctl(cdrom->id, CDROMPLAYMSF, &playtime));
 }

 /* Pause play */
 static int SDL_SYS_CDPause(SDL_CD *cdrom)
 {
 	return(SDL_SYS_CDioctl(cdrom->id, CDROMPAUSE, 0));
 }

 /* Resume play */
 static int SDL_SYS_CDResume(SDL_CD *cdrom)
 {
 	return(SDL_SYS_CDioctl(cdrom->id, CDROMRESUME, 0));
 }

 /* Stop play */
 static int SDL_SYS_CDStop(SDL_CD *cdrom)
 {
 	return(SDL_SYS_CDioctl(cdrom->id, CDROMSTOP, 0));
 }

 /* Eject the CD-ROM */
 static int SDL_SYS_CDEject(SDL_CD *cdrom)
 {
 	return(SDL_SYS_CDioctl(cdrom->id, CDROMEJECT, 0));
 }

 /* Close the CD-ROM handle */
 static void SDL_SYS_CDClose(SDL_CD *cdrom)
 {
 	close(cdrom->id);
 }

 void SDL_SYS_CDQuit(void)
 {
 	int i;

 	if ( SDL_numcds > 0 ) {
 		for ( i=0; i<SDL_numcds; ++i ) {
 			SDL_free(SDL_cdlist[i]);
 		}
 		SDL_numcds = 0;
 	}
 }

 #endif /* SDL_CDROM_LINUX */
	/*
	SDL - Simple DirectMedia Layer
	Copyright (C) 1997-2009 Sam Lantinga

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.

	This library 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. See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public
	License along with this library; if not, write to the Free Software
	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

	Sam Lantinga
	slouken@libsdl.org
	*/
	#include "SDL_config.h"

	#ifdef SDL_CDROM_LINUX

	/* Functions for system-level CD-ROM audio control */

	#include <string.h> /* For strerror() */
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <sys/ioctl.h>
	#include <fcntl.h>
	#include <errno.h>
	#include <unistd.h>
	#ifdef __LINUX__
	#ifdef HAVE_LINUX_VERSION_H
	/* linux 2.6.9 workaround */
	#include <linux/version.h>
	#if LINUX_VERSION_CODE == KERNEL_VERSION(2,6,9)
	#include <asm/types.h>
	#define __le64 __u64
	#define __le32 __u32
	#define __le16 __u16
	#define __be64 __u64
	#define __be32 __u32
	#define __be16 __u16
	#endif /* linux 2.6.9 workaround */
	#endif /* HAVE_LINUX_VERSION_H */
	#include <linux/cdrom.h>
	#endif
	#ifdef __SVR4
	#include <sys/cdio.h>
	#endif

	/* Define this to use the alternative getmntent() code */
	#ifndef __SVR4
	#define USE_MNTENT
	#endif

	#ifdef USE_MNTENT
	#if defined(__USLC__)
	#include <sys/mntent.h>
	#else
	#include <mntent.h>
	#endif

	#ifndef _PATH_MNTTAB
	#ifdef MNTTAB
	#define _PATH_MNTTAB MNTTAB
	#else
	#define _PATH_MNTTAB "/etc/fstab"
	#endif
	#endif /* !_PATH_MNTTAB */

	#ifndef _PATH_MOUNTED
	#define _PATH_MOUNTED "/etc/mtab"
	#endif /* !_PATH_MOUNTED */

	#ifndef MNTTYPE_CDROM
	#define MNTTYPE_CDROM "iso9660"
	#endif
	#ifndef MNTTYPE_SUPER
	#define MNTTYPE_SUPER "supermount"
	#endif
	#endif /* USE_MNTENT */

	#include "SDL_cdrom.h"
	#include "../SDL_syscdrom.h"


	/* The maximum number of CD-ROM drives we'll detect */
	#define MAX_DRIVES 16

	/* A list of available CD-ROM drives */
	static char *SDL_cdlist[MAX_DRIVES];
	static dev_t SDL_cdmode[MAX_DRIVES];

	/* The system-dependent CD control functions */
	static const char *SDL_SYS_CDName(int drive);
	static int SDL_SYS_CDOpen(int drive);
	static int SDL_SYS_CDGetTOC(SDL_CD *cdrom);
	static CDstatus SDL_SYS_CDStatus(SDL_CD cdrom, int position);
	static int SDL_SYS_CDPlay(SDL_CD *cdrom, int start, int length);
	static int SDL_SYS_CDPause(SDL_CD *cdrom);
	static int SDL_SYS_CDResume(SDL_CD *cdrom);
	static int SDL_SYS_CDStop(SDL_CD *cdrom);
	static int SDL_SYS_CDEject(SDL_CD *cdrom);
	static void SDL_SYS_CDClose(SDL_CD *cdrom);

	/* Some ioctl() errno values which occur when the tray is empty */
	#ifndef ENOMEDIUM
	#define ENOMEDIUM ENOENT
	#endif
	#define ERRNO_TRAYEMPTY(errno) \
	((errno == EIO) \|\| (errno == ENOENT) \|\| \
	(errno == EINVAL) \|\| (errno == ENOMEDIUM))

	/* Check a drive to see if it is a CD-ROM */
	static int CheckDrive(char drive, char mnttype, struct stat *stbuf)
	{
	int is_cd, cdfd;
	struct cdrom_subchnl info;

	/* If it doesn't exist, return -1 */
	if ( stat(drive, stbuf) < 0 ) {
	return(-1);
	}

	/* If it does exist, verify that it's an available CD-ROM */
	is_cd = 0;
	if ( S_ISCHR(stbuf->st_mode) \|\| S_ISBLK(stbuf->st_mode) ) {
	cdfd = open(drive, (O_RDONLY\|O_NONBLOCK), 0);
	if ( cdfd >= 0 ) {
	info.cdsc_format = CDROM_MSF;
	/* Under Linux, EIO occurs when a disk is not present.
	*/
	if ( (ioctl(cdfd, CDROMSUBCHNL, &info) == 0) \|\|
	ERRNO_TRAYEMPTY(errno) ) {
	is_cd = 1;
	}
	close(cdfd);
	}
	#ifdef USE_MNTENT
	/* Even if we can't read it, it might be mounted */
	else if ( mnttype && (SDL_strcmp(mnttype, MNTTYPE_CDROM) == 0) ) {
	is_cd = 1;
	}
	#endif
	}
	return(is_cd);
	}

	/* Add a CD-ROM drive to our list of valid drives */
	static void AddDrive(char drive, struct stat stbuf)
	{
	int i;

	if ( SDL_numcds < MAX_DRIVES ) {
	/* Check to make sure it's not already in our list.
	This can happen when we see a drive via symbolic link.
	*/
	for ( i=0; i<SDL_numcds; ++i ) {
	if ( stbuf->st_rdev == SDL_cdmode[i] ) {
	#ifdef DEBUG_CDROM
	fprintf(stderr, "Duplicate drive detected: %s == %s\n", drive, SDL_cdlist[i]);
	#endif
	return;
	}
	}

	/* Add this drive to our list */
	i = SDL_numcds;
	SDL_cdlist[i] = SDL_strdup(drive);
	if ( SDL_cdlist[i] == NULL ) {
	SDL_OutOfMemory();
	return;
	}
	SDL_cdmode[i] = stbuf->st_rdev;
	++SDL_numcds;
	#ifdef DEBUG_CDROM
	fprintf(stderr, "Added CD-ROM drive: %s\n", drive);
	#endif
	}
	}

	#ifdef USE_MNTENT
	static void CheckMounts(const char *mtab)
	{
	FILE *mntfp;
	struct mntent *mntent;
	struct stat stbuf;

	mntfp = setmntent(mtab, "r");
	if ( mntfp != NULL ) {
	char *tmp;
	char *mnt_type;
	size_t mnt_type_len;
	char *mnt_dev;
	size_t mnt_dev_len;

	while ( (mntent=getmntent(mntfp)) != NULL ) {
	mnt_type_len = SDL_strlen(mntent->mnt_type) + 1;
	mnt_type = SDL_stack_alloc(char, mnt_type_len);
	if (mnt_type == NULL)
	continue; /* maybe you'll get lucky next time. */

	mnt_dev_len = SDL_strlen(mntent->mnt_fsname) + 1;
	mnt_dev = SDL_stack_alloc(char, mnt_dev_len);
	if (mnt_dev == NULL) {
	SDL_stack_free(mnt_type);
	continue;
	}

	SDL_strlcpy(mnt_type, mntent->mnt_type, mnt_type_len);
	SDL_strlcpy(mnt_dev, mntent->mnt_fsname, mnt_dev_len);

	/* Handle "supermount" filesystem mounts */
	if ( SDL_strcmp(mnt_type, MNTTYPE_SUPER) == 0 ) {
	tmp = SDL_strstr(mntent->mnt_opts, "fs=");
	if ( tmp ) {
	SDL_stack_free(mnt_type);
	mnt_type = SDL_strdup(tmp + SDL_strlen("fs="));
	if ( mnt_type ) {
	tmp = SDL_strchr(mnt_type, ',');
	if ( tmp ) {
	*tmp = '\0';
	}
	}
	}
	tmp = SDL_strstr(mntent->mnt_opts, "dev=");
	if ( tmp ) {
	SDL_stack_free(mnt_dev);
	mnt_dev = SDL_strdup(tmp + SDL_strlen("dev="));
	if ( mnt_dev ) {
	tmp = SDL_strchr(mnt_dev, ',');
	if ( tmp ) {
	*tmp = '\0';
	}
	}
	}
	}
	if ( SDL_strcmp(mnt_type, MNTTYPE_CDROM) == 0 ) {
	#ifdef DEBUG_CDROM
	fprintf(stderr, "Checking mount path from %s: %s mounted on %s of %s\n",
	mtab, mnt_dev, mntent->mnt_dir, mnt_type);
	#endif
	if (CheckDrive(mnt_dev, mnt_type, &stbuf) > 0) {
	AddDrive(mnt_dev, &stbuf);
	}
	}
	SDL_stack_free(mnt_dev);
	SDL_stack_free(mnt_type);
	}
	endmntent(mntfp);
	}
	}
	#endif /* USE_MNTENT */

	int SDL_SYS_CDInit(void)
	{
	/* checklist: /dev/cdrom, /dev/hd?, /dev/scd? /dev/sr? */
	static char *checklist[] = {
	"cdrom", "?a hd?", "?0 scd?", "?0 sr?", NULL
	};
	char *SDLcdrom;
	int i, j, exists;
	char drive[32];
	struct stat stbuf;

	/* Fill in our driver capabilities */
	SDL_CDcaps.Name = SDL_SYS_CDName;
	SDL_CDcaps.Open = SDL_SYS_CDOpen;
	SDL_CDcaps.GetTOC = SDL_SYS_CDGetTOC;
	SDL_CDcaps.Status = SDL_SYS_CDStatus;
	SDL_CDcaps.Play = SDL_SYS_CDPlay;
	SDL_CDcaps.Pause = SDL_SYS_CDPause;
	SDL_CDcaps.Resume = SDL_SYS_CDResume;
	SDL_CDcaps.Stop = SDL_SYS_CDStop;
	SDL_CDcaps.Eject = SDL_SYS_CDEject;
	SDL_CDcaps.Close = SDL_SYS_CDClose;

	/* Look in the environment for our CD-ROM drive list */
	SDLcdrom = SDL_getenv("SDL_CDROM"); /* ':' separated list of devices */
	if ( SDLcdrom != NULL ) {
	char cdpath, delim;
	size_t len = SDL_strlen(SDLcdrom)+1;
	cdpath = SDL_stack_alloc(char, len);
	if ( cdpath != NULL ) {
	SDL_strlcpy(cdpath, SDLcdrom, len);
	SDLcdrom = cdpath;
	do {
	delim = SDL_strchr(SDLcdrom, ':');
	if ( delim ) {
	*delim++ = '\0';
	}
	#ifdef DEBUG_CDROM
	fprintf(stderr, "Checking CD-ROM drive from SDL_CDROM: %s\n", SDLcdrom);
	#endif
	if ( CheckDrive(SDLcdrom, NULL, &stbuf) > 0 ) {
	AddDrive(SDLcdrom, &stbuf);
	}
	if ( delim ) {
	SDLcdrom = delim;
	} else {
	SDLcdrom = NULL;
	}
	} while ( SDLcdrom );
	SDL_stack_free(cdpath);
	}

	/* If we found our drives, there's nothing left to do */
	if ( SDL_numcds > 0 ) {
	return(0);
	}
	}

	#ifdef USE_MNTENT
	/* Check /dev/cdrom first :-) */
	if (CheckDrive("/dev/cdrom", NULL, &stbuf) > 0) {
	AddDrive("/dev/cdrom", &stbuf);
	}

	/* Now check the currently mounted CD drives */
	CheckMounts(_PATH_MOUNTED);

	/* Finally check possible mountable drives in /etc/fstab */
	CheckMounts(_PATH_MNTTAB);

	/* If we found our drives, there's nothing left to do */
	if ( SDL_numcds > 0 ) {
	return(0);
	}
	#endif /* USE_MNTENT */

	/* Scan the system for CD-ROM drives.
	Not always 100% reliable, so use the USE_MNTENT code above first.
	*/
	for ( i=0; checklist[i]; ++i ) {
	if ( checklist[i][0] == '?' ) {
	char *insert;
	exists = 1;
	for ( j=checklist[i][1]; exists; ++j ) {
	SDL_snprintf(drive, SDL_arraysize(drive), "/dev/%s", &checklist[i][3]);
	insert = SDL_strchr(drive, '?');
	if ( insert != NULL ) {
	*insert = j;
	}
	#ifdef DEBUG_CDROM
	fprintf(stderr, "Checking possible CD-ROM drive: %s\n", drive);
	#endif
	switch (CheckDrive(drive, NULL, &stbuf)) {
	/* Drive exists and is a CD-ROM */
	case 1:
	AddDrive(drive, &stbuf);
	break;
	/* Drive exists, but isn't a CD-ROM */
	case 0:
	break;
	/* Drive doesn't exist */
	case -1:
	exists = 0;
	break;
	}
	}
	} else {
	SDL_snprintf(drive, SDL_arraysize(drive), "/dev/%s", checklist[i]);
	#ifdef DEBUG_CDROM
	fprintf(stderr, "Checking possible CD-ROM drive: %s\n", drive);
	#endif
	if ( CheckDrive(drive, NULL, &stbuf) > 0 ) {
	AddDrive(drive, &stbuf);
	}
	}
	}
	return(0);
	}

	/* General ioctl() CD-ROM command function */
	static int SDL_SYS_CDioctl(int id, int command, void *arg)
	{
	int retval;

	retval = ioctl(id, command, arg);
	if ( retval < 0 ) {
	SDL_SetError("ioctl() error: %s", strerror(errno));
	}
	return(retval);
	}

	static const char *SDL_SYS_CDName(int drive)
	{
	return(SDL_cdlist[drive]);
	}

	static int SDL_SYS_CDOpen(int drive)
	{
	return(open(SDL_cdlist[drive], (O_RDONLY\|O_NONBLOCK), 0));
	}

	static int SDL_SYS_CDGetTOC(SDL_CD *cdrom)
	{
	struct cdrom_tochdr toc;
	int i, okay;
	struct cdrom_tocentry entry;

	okay = 0;
	if ( SDL_SYS_CDioctl(cdrom->id, CDROMREADTOCHDR, &toc) == 0 ) {
	cdrom->numtracks = toc.cdth_trk1-toc.cdth_trk0+1;
	if ( cdrom->numtracks > SDL_MAX_TRACKS ) {
	cdrom->numtracks = SDL_MAX_TRACKS;
	}
	/* Read all the track TOC entries */
	for ( i=0; i<=cdrom->numtracks; ++i ) {
	if ( i == cdrom->numtracks ) {
	cdrom->track[i].id = CDROM_LEADOUT;
	} else {
	cdrom->track[i].id = toc.cdth_trk0+i;
	}
	entry.cdte_track = cdrom->track[i].id;
	entry.cdte_format = CDROM_MSF;
	if ( SDL_SYS_CDioctl(cdrom->id, CDROMREADTOCENTRY,
	&entry) < 0 ) {
	break;
	} else {
	if ( entry.cdte_ctrl & CDROM_DATA_TRACK ) {
	cdrom->track[i].type = SDL_DATA_TRACK;
	} else {
	cdrom->track[i].type = SDL_AUDIO_TRACK;
	}
	cdrom->track[i].offset = MSF_TO_FRAMES(
	entry.cdte_addr.msf.minute,
	entry.cdte_addr.msf.second,
	entry.cdte_addr.msf.frame);
	cdrom->track[i].length = 0;
	if ( i > 0 ) {
	cdrom->track[i-1].length =
	cdrom->track[i].offset-
	cdrom->track[i-1].offset;
	}
	}
	}
	if ( i == (cdrom->numtracks+1) ) {
	okay = 1;
	}
	}
	return(okay ? 0 : -1);
	}

	/* Get CD-ROM status */
	static CDstatus SDL_SYS_CDStatus(SDL_CD cdrom, int position)
	{
	CDstatus status;
	struct cdrom_tochdr toc;
	struct cdrom_subchnl info;

	info.cdsc_format = CDROM_MSF;
	if ( ioctl(cdrom->id, CDROMSUBCHNL, &info) < 0 ) {
	if ( ERRNO_TRAYEMPTY(errno) ) {
	status = CD_TRAYEMPTY;
	} else {
	status = CD_ERROR;
	}
	} else {
	switch (info.cdsc_audiostatus) {
	case CDROM_AUDIO_INVALID:
	case CDROM_AUDIO_NO_STATUS:
	/* Try to determine if there's a CD available */
	if (ioctl(cdrom->id, CDROMREADTOCHDR, &toc)==0)
	status = CD_STOPPED;
	else
	status = CD_TRAYEMPTY;
	break;
	case CDROM_AUDIO_COMPLETED:
	status = CD_STOPPED;
	break;
	case CDROM_AUDIO_PLAY:
	status = CD_PLAYING;
	break;
	case CDROM_AUDIO_PAUSED:
	/* Workaround buggy CD-ROM drive */
	if ( info.cdsc_trk == CDROM_LEADOUT ) {
	status = CD_STOPPED;
	} else {
	status = CD_PAUSED;
	}
	break;
	default:
	status = CD_ERROR;
	break;
	}
	}
	if ( position ) {
	if ( status == CD_PLAYING \|\| (status == CD_PAUSED) ) {
	*position = MSF_TO_FRAMES(
	info.cdsc_absaddr.msf.minute,
	info.cdsc_absaddr.msf.second,
	info.cdsc_absaddr.msf.frame);
	} else {
	*position = 0;
	}
	}
	return(status);
	}

	/* Start play */
	static int SDL_SYS_CDPlay(SDL_CD *cdrom, int start, int length)
	{
	struct cdrom_msf playtime;

	FRAMES_TO_MSF(start,
	&playtime.cdmsf_min0, &playtime.cdmsf_sec0, &playtime.cdmsf_frame0);
	FRAMES_TO_MSF(start+length,
	&playtime.cdmsf_min1, &playtime.cdmsf_sec1, &playtime.cdmsf_frame1);
	#ifdef DEBUG_CDROM
	fprintf(stderr, "Trying to play from %d:%d:%d to %d:%d:%d\n",
	playtime.cdmsf_min0, playtime.cdmsf_sec0, playtime.cdmsf_frame0,
	playtime.cdmsf_min1, playtime.cdmsf_sec1, playtime.cdmsf_frame1);
	#endif
	return(SDL_SYS_CDioctl(cdrom->id, CDROMPLAYMSF, &playtime));
	}

	/* Pause play */
	static int SDL_SYS_CDPause(SDL_CD *cdrom)
	{
	return(SDL_SYS_CDioctl(cdrom->id, CDROMPAUSE, 0));
	}

	/* Resume play */
	static int SDL_SYS_CDResume(SDL_CD *cdrom)
	{
	return(SDL_SYS_CDioctl(cdrom->id, CDROMRESUME, 0));
	}

	/* Stop play */
	static int SDL_SYS_CDStop(SDL_CD *cdrom)
	{
	return(SDL_SYS_CDioctl(cdrom->id, CDROMSTOP, 0));
	}

	/* Eject the CD-ROM */
	static int SDL_SYS_CDEject(SDL_CD *cdrom)
	{
	return(SDL_SYS_CDioctl(cdrom->id, CDROMEJECT, 0));
	}

	/* Close the CD-ROM handle */
	static void SDL_SYS_CDClose(SDL_CD *cdrom)
	{
	close(cdrom->id);
	}

	void SDL_SYS_CDQuit(void)
	{
	int i;

	if ( SDL_numcds > 0 ) {
	for ( i=0; i<SDL_numcds; ++i ) {
	SDL_free(SDL_cdlist[i]);
	}
	SDL_numcds = 0;
	}
	}

	#endif /* SDL_CDROM_LINUX */