cdio(7I) Ioctl Requests cdio(7I)
NAME
cdio - CD-ROM control operations
SYNOPSIS
#include <sys/cdio.h>
DESCRIPTION
The set of ioctl(2) commands described below are used to perform audio and CD-ROM specific operations. Basic to these cdio ioctl requests
are the definitions in <sys/cdio.h>.
Several CD-ROM specific commands can report addresses either in LBA (Logical Block Address) format or in MSF (Minute, Second, Frame) for-
mat. The READ HEADER, READ SUBCHANNEL, and READ TABLE OF CONTENTS commands have this feature.
LBA format represents the logical block address for the CD-ROM absolute address field or for the offset from the beginning of the current
track expressed as a number of logical blocks in a CD-ROM track relative address field. MSF format represents the physical address written
on CD-ROM discs, expressed as a sector count relative to either the beginning of the medium or the beginning of the current track.
IOCTLS
The following I/O controls do not have any additional data passed into or received from them.
CDROMSTART
This ioctl() spins up the disc and seeks to the last address requested.
CDROMSTOP
This ioctl() spins down the disc.
CDROMPAUSE
This ioctl() pauses the current audio play operation.
CDROMRESUME
This ioctl() resumes the paused audio play operation.
CDROMEJECT
This ioctl() ejects the caddy with the disc.
CDROMCLOSETRAY
This ioctl() closes the caddy with the disc.
The following I/O controls require a pointer to the structure for that ioctl(), with data being passed into the ioctl().
CDROMPLAYMSF
This ioctl() command requests the drive to output the audio signals at the specified starting address and continue the audio play until
the specified ending address is detected. The address is in MSF format. The third argument of this ioctl() call is a pointer to the
type struct cdrom_msf.
/*
* definition of play audio msf structure
*/
struct cdrom_msf {
unsigned char cdmsf_min0; /* starting minute*/
unsigned char cdmsf_sec0; /* starting second*/
unsigned char cdmsf_frame0; /*starting frame*/
unsigned char cdmsf_min1; /* ending minute */
unsigned char cdmsf_sec1; /* ending second */
unsigned char cdmsf_frame1; /* ending frame */
};
The CDROMREADTOCENTRY ioctl request may be used to obtain the start time for a track. An approximation of the finish time can be
obtained by using the CDROMREADTOCENTRY ioctl request to retrieve the start time of the track following the current track.
The leadout track is the next consecutive track after the last audio track. Hence, the start time of the leadout track may be used as
the effective finish time of the last audio track.
CDROMPLAYTRKIND
This ioctl() command is similar to CDROMPLAYMSF. The starting and ending address is in track/index format. The third argument of the
ioctl() call is a pointer to the type struct cdrom_ti.
/*
* definition of play audio track/index structure
*/
struct cdrom_ti {
unsigned char cdti_trk0; /* starting track*/
unsigned char cdti_ind0; /* starting index*/
unsigned char cdti_trk1; /* ending track */
unsigned char cdti_ind1; /* ending index */
};
CDROMVOLCTRL
This ioctl() command controls the audio output level. The SCSI command allows the control of up to four channels. The current implemen-
tation of the supported CD-ROM drive only uses channel 0 and channel 1. The valid values of volume control are between 0x00 and 0xFF,
with a value of 0xFF indicating maximum volume. The third argument of the ioctl() call is a pointer to struct cdrom_volctrl which con-
tains the output volume values.
/*
* definition of audio volume control structure
*/
struct cdrom_volctrl {
unsigned char channel0;
unsigned char channel1;
unsigned char channel2;
unsigned char channel3;
};
The following I/O controls take a pointer that will have data returned to the user program from the CD-ROM driver.
CDROMREADTOCHDR
This ioctl() command returns the header of the table of contents (TOC). The header consists of the starting tracking number and the
ending track number of the disc. These two numbers are returned through a pointer of struct cdrom_tochdr. While the disc can start at
any number, all tracks between the first and last tracks are in contiguous ascending order.
/*
* definition of read toc header structure
*/
struct cdrom_tochdr {
unsigned char cdth_trk0; /* starting track*/
unsigned char cdth_trk1; /* ending track*/
};
CDROMREADTOCENTRY
This ioctl() command returns the information of a specified track. The third argument of the function call is a pointer to the type
struct cdrom_tocentry. The caller needs to supply the track number and the address format. This command will return a 4-bit adr
field, a 4-bit ctrl field, the starting address in MSF format or LBA format, and the data mode if the track is a data track. The ctrl
field specifies whether the track is data or audio.
/*
* definition of read toc entry structure
*/
struct cdrom_tocentry {
unsigned char cdte_track;
unsigned char cdte_adr :4;
unsigned char cdte_ctrl :4;
unsigned char cdte_format;
union {
struct {
unsigned char minute;
unsigned char second;
unsigned char frame;
} msf;
int lba;
} cdte_addr;
unsigned char cdte_datamode;
};
To get the information from the leadout track, the following value is appropriate for the cdte_track field:
CDROM_LEADOUT Leadout track
To get the information from the data track, the following value is appropriate for the cdte_ctrl field:
CDROM_DATA_TRACK Data track
The following values are appropriate for the cdte_format field:
CDROM_LBA LBA format
CDROM_MSF MSF format
CDROMSUBCHNL
This ioctl() command reads the Q sub-channel data of the current block. The subchannel data includes track number, index number, abso-
lute CD-ROM address, track relative CD-ROM address, control data and audio status. All information is returned through a pointer to
struct cdrom_subchnl. The caller needs to supply the address format for the returned address.
struct cdrom_subchnl {
unsigned char cdsc_format;
unsigned char cdsc_audiostatus;
unsigned char cdsc_adr: 4;
unsigned char cdsc_ctrl: 4;
unsigned char cdsc_trk;
unsigned char cdsc_ind;
union {
struct {
unsigned char minute;
unsigned char second;
unsigned char frame;
} msf;
int lba;
} cdsc_absaddr;
union {
struct {
unsigned char minute;
unsigned char second;
unsigned char frame;
} msf;
int lba;
} cdsc_reladdr;
};
The following values are valid for the audio status field returned from READ SUBCHANNEL command:
CDROM_AUDIO_INVALID Audio status not supported.
CDROM_AUDIO_PLAY Audio play operation in progress.
CDROM_AUDIO_PAUSED Audio play operation paused.
CDROM_AUDIO_COMPLETED Audio play successfully completed.
CDROM_AUDIO_ERROR Audio play stopped due to error.
CDROM_AUDIO_NO_STATUS No current audio status to return.
CDROMREADOFFSET
This ioctl() command returns the absolute CD-ROM address of the first track in the last session of a Multi-Session CD-ROM. The third
argument of the ioctl() call is a pointer to an int.
CDROMCDDA
This ioctl() command returns the CD-DA data or the subcode data. The third argument of the ioctl() call is a pointer to the type struct
cdrom_cdda. In addition to allocating memory and supplying its address, the caller needs to supply the starting address of the data,
the transfer length in terms of the number of blocks to be transferred, and the subcode options. The caller also needs to issue the
CDROMREADTOCENTRY ioctl() to find out which tracks contain CD-DA data before issuing this ioctl().
/*
* Definition of CD-DA structure
*/
struct cdrom_cdda {
unsigned int cdda_addr;
unsigned int cdda_length;
caddr_t cdda_data;
unsigned char cdda_subcode;
};
cdda_addr signifies the starting logical block address.
cdda_length signifies the transfer length in blocks. The length of the block depends on the cdda_subcode selection, which is explained
below.
To get the subcode information related to CD-DA data, the following values are appropriate for the cdda_subcode field:
CDROM_DA_NO_SUBCODE CD-DA data with no subcode.
CDROM_DA_SUBQ CD-DA data with sub Q code.
CDROM_DA_ALL_SUBCODE CD-DA data with all subcode.
CDROM_DA_SUBCODE_ONLY All subcode only.
To allocate the memory related to CD-DA and/or subcode data, the following values are appropriate for each data block transferred:
CD-DA data with no subcode 2352 bytes
CD-DA data with sub Q code 2368 bytes
CD-DA data with all subcode 2448 bytes
All subcode only 96 bytes
CDROMCDXA
This ioctl() command returns the CD-ROM XA (CD-ROM Extended Architecture) data according to CD-ROM XA format. The third argument of
the ioctl() call is a pointer to the type struct cdrom_cdxa. In addition to allocating memory and supplying its address, the caller
needs to supply the starting address of the data, the transfer length in terms of number of blocks, and the format. The caller also
needs to issue the CDROMREADTOCENTRY ioctl() to find out which tracks contain CD-ROM XA data before issuing this ioctl().
/*
* Definition of CD-ROM XA structure
*/
struct cdrom_cdxa {
unsigned int cdxa_addr;
unsigned int cdxa_length;
caddr_t cdxa_data;
unsigned char cdxa_format;
};
To get the proper CD-ROM XA data, the following values are appropriate for the cdxa_format field:
CDROM_XA_DATA CD-ROM XA data only
CDROM_XA_SECTOR_DATA CD-ROM XA all sector data
CDROM_XA_DATA_W_ERROR CD-ROM XA data with error flags data
To allocate the memory related to CD-ROM XA format, the following values are appropriate for each data block transferred:
CD-ROM XA data only 2048 bytes
CD-ROM XA all sector data 2352 bytes
CD-ROM XA data with error flags data 2646 bytes
CDROMSUBCODE
This ioctl() command returns raw subcode data (subcodes P ~ W are described in the "Red Book," see SEE ALSO) to the initiator while
the target is playing audio. The third argument of the ioctl() call is a pointer to the type struct cdrom_subcode. The caller needs
to supply the transfer length in terms of number of blocks and allocate memory for subcode data. The memory allocated should be a mul-
tiple of 96 bytes depending on the transfer length.
/*
* Definition of subcode structure
*/
struct cdrom_subcode {
unsigned int cdsc_length;
caddr_t cdsc_addr;
};
The next group of I/O controls get and set various CD-ROM drive parameters.
CDROMGBLKMODE
This ioctl() command returns the current block size used by the CD-ROM drive. The third argument of the ioctl() call is a pointer to
an integer.
CDROMSBLKMODE
This ioctl() command requests the CD-ROM drive to change from the current block size to the requested block size. The third argument
of the ioctl() call is an integer which contains the requested block size.
This ioctl() command operates in exclusive-use mode only. The caller must ensure that no other processes can operate on the same CD-
ROM device before issuing this ioctl(). read(2) behavior subsequent to this ioctl() remains the same: the caller is still constrained
to read the raw device on block boundaries and in block multiples.
To set the proper block size, the following values are appropriate:
CDROM_BLK_512 512 bytes
CDROM_BLK_1024 1024 bytes
CDROM_BLK_2048 2048 bytes
CDROM_BLK_2056 2056 bytes
CDROM_BLK_2336 2336 bytes
CDROM_BLK_2340 2340 bytes
CDROM_BLK_2352 2352 bytes
CDROM_BLK_2368 2368 bytes
CDROM_BLK_2448 2448 bytes
CDROM_BLK_2646 2646 bytes
CDROM_BLK_2647 2647 bytes
CDROMGDRVSPEED
This ioctl() command returns the current CD-ROM drive speed. The third argument of the ioctl() call is a pointer to an integer.
CDROMSDRVSPEED
This ioctl() command requests the CD-ROM drive to change the current drive speed to the requested drive speed. This speed setting is
only applicable when reading data areas. The third argument of the ioctl() is an integer which contains the requested drive speed.
To set the CD-ROM drive to the proper speed, the following values are appropriate:
CDROM_NORMAL_SPEED 150k/second
CDROM_DOUBLE_SPEED 300k/second
CDROM_QUAD_SPEED 600k/second
CDROM_MAXIMUM_SPEED 300k/second (2x drive) 600k/second (4x drive)
Note that these numbers are only accurate when reading 2048 byte blocks. The CD-ROM drive will automatically switch to normal speed
when playing audio tracks and will switch back to the speed setting when accessing data.
SEE ALSO
ioctl(2), read(2)
N. V. Phillips and Sony Corporation, System Description Compact Disc Digital Audio, ("Red Book").
N. V. Phillips and Sony Corporation, System Description of Compact Disc Read Only Memory, ("Yellow Book").
N. V. Phillips, Microsoft, and Sony Corporation, System Description CD-ROM XA, 1991.
Volume and File Structure of CD-ROM for Information Interchange, ISO 9660:1988(E).
SCSI-2 Standard, document X3T9.2/86-109
SCSI Multimedia Commands, Version 2 (MMC-2)
NOTES
The CDROMCDDA, CDROMCDXA, CDROMSUBCODE, CDROMGDRVSPEED, CDROMSDRVSPEED, and some of the block sizes in CDROMSBLKMODE are designed for new
Sun-supported CD-ROM drives and might not work on some of the older CD-ROM drives.
CDROMCDDA, CDROMCDXA and CDROMSUBCODE will return error if the transfer length exceeds valid limits as determined appropriate. Example: for
MMC-2 drives, length can not exceed 3 bytes (i.e. 0xffffff). The same restriction is enforced for older, pre-MMC-2 drives, as no limit was
published for these older drives (and 3 bytes is reasonable for all media). Note that enforcing this limit does not imply that values
passed in below this limit will actually be applicable for each and every piece of media.
The interface to this device is preliminary and subject to change in future releases. Programs should be written in a modular fashion so
that future changes can be easily incorporated.
SunOS 5.10 4 Oct 2001 cdio(7I)