NAME

ttcompat - V7, 4BSD and XENIX STREAMS compatibility module

SYNOPSIS

#define BSD_COMP
#include <sys/stropts.h>
#include <sys/ioctl.h>
ioctl(fd, I_PUSH, "ttcompat");

DESCRIPTION

ttcompat is a STREAMS module that translates the ioctl calls supported by the older Version 7, 4BSD, and XENIX terminal drivers into the ioctl calls supported by the termio interface (see termio(4I)). All other messages pass through this module unchanged; the behavior of read and write calls is unchanged, as is the behavior of ioctl calls other than the ones supported by ttcompat.

This module can be automatically pushed onto a stream using the autopush mechanism when a terminal device is opened; it does not have to be explicitly pushed onto a stream. This module requires that the termios interface be supported by the modules and the application can push the driver downstream. The TCGETS, TCSETS, and TCSETSF ioctl calls must be supported. If any information set or fetched by those ioctl calls is not supported by the modules and driver downstream, some of the V7/4BSD/XENIX functions may not be supported. For example, if the CBAUD bits in the c_cflag field are not supported, the functions provided by the sg_ispeed and sg_ospeed fields of the sgttyb structure (see below) will not be supported. If the TCFLSH ioctl is not supported, the function provided by the TIOCFLUSH ioctl will not be supported. If the TCXONC ioctl is not supported, the functions provided by the TIOCSTOP and TIOCSTART ioctl calls will not be supported. If the TIOCMBIS and TIOCMBIC ioctl calls are not supported, the functions provided by the TIOCSDTR and TIOCCDTR ioctl calls will not be supported.

The basic ioctl calls use the sgttyb structure defined by <sys/ttold.h> (included by <sys/ioctl.h>):

struct   sgttyb   {
	char	sg_ispeed;
	char	sg_ospeed;
	char	sg_erase;
	char	sg_kill;
	int	sg_flags;
};

The sg_ispeed and sg_ospeed fields describe the input and output speeds of the device. If the speed set on the device is over B38400, then it is reported as B38400 for compatibility reasons. If it is set to B38400 and the current speed is over B38400, the change is ignored. See TIOCGETP and TIOCSETP below. The sg_erase and sg_kill fields of the argument structure specify the erase and kill characters respectively, and reflect the values in the VERASE and VKILL members of the c_cc field of the termios structure.

The sg_flags field of the argument structure contains several flags that determine the system's treatment of the terminal. They are mapped into flags in fields of the terminal state, represented by the termios structure.

Delay type 0 (NL0, TAB0, CR0, FF0, BS0) is always mapped into the equivalent delay type 0 in the c_oflag field of the termios structure. Other delay mappings are performed as follows:

If previous TIOCLSET or TIOCLBIS ioctl calls have not selected LITOUT or PASS8 mode, and if RAW mode is not selected, the ISTRIP flag is set in the c_iflag field of the termios structure, and the EVENP and ODDP flags control the parity of characters sent to the terminal and accepted from the terminal, as follows:

0 (neither EVENP nor ODDP)

EVENP

ODDP

EVENP|ODDP or ANYP

The RAW flag disables all output processing (the OPOST flag in the c_oflag field, and the XCASE and IEXTEN flags in the c_iflag field are cleared in the termios structure) and input processing (all flags in the c_iflag field other than the IXOFF and IXANY flags are cleared in the termios structure). Eight bits of data, with no parity bit are accepted on input and generated on output; the character size is set to CS8 and the PARENB and PARODD flags are cleared in the c_cflag field of the termios structure. The signal-generating and line-editing control characters are disabled by clearing the ISIG and ICANON flags in the c_iflag field of the termios structure.

The CRMOD flag turns input carriage return characters into linefeed characters, and output linefeed characters to be sent as a carriage return followed by a linefeed. The ICRNL flag in the c_iflag field, and the OPOST and ONLCR flags in the c_oflag field, are set in the termios structure.

The LCASE flag maps upper-case letters in the ASCII character set to their lower-case equivalents on input (the IUCLC flag is set in the c_iflag field), and maps lower-case letters in the ASCII character set to their upper-case equivalents on output (the OLCUC flag is set in the c_oflag field). Escape sequences are accepted on input, and generated on output, to handle certain ASCII characters not supported by older terminals (the XCASE flag is set in the c_lflag field).

Other flags are directly mapped to flags in the termios structure:

Another structure associated with each terminal specifies characters that are special in both the old Version 7 and the newer 4BSD terminal interfaces. The following structure is defined by <sys/ttold.h>:

struct   tchars   {


          char t_intrc;     /* interrupt */


          char t_quitc;     /* quit */


          char t_startc; /* start output */


          char t_stopc;     /* stop output */


          char t_eofc;        /* end-of-file */


          char t_brkc;        /* input delimiter (like nl) */


     };

XENIX defines the tchar structure as tc. The characters are mapped to members of the c_cc field of the termios structure as follows:

       tchars                c_cc index


       t_intrc               VINTR


       t_quitc               VQUIT


       t_startc              VSTART


       t_stopc               VSTOP


       t_eofc                VEOF


       t_brkc                VEOL

Also associated with each terminal is a local flag word (TIOCLSET and TIOCLGET), specifying flags supported by the new 4BSD terminal interface. Most of these flags are directly mapped to flags in the termios structure:

Each flag has a corresponding equivalent sg_flags value. The sg_flags definitions omit the leading "L"; for example, TIOCSETP with sg_flags set to TOSTOP is equivalent to TIOCLSET with LTOSTOP.

Another structure associated with each terminal is the ltchars structure which defines control characters for the new 4BSD terminal interface. Its structure is:

struct ltchars {


   char t_suspc;  /* stop process signal */


   char t_dsuspc; /* delayed stop process signal */


   char t_rprntc; /* reprint line */


   char t_flushc; /*flush output (toggles) */


   char t_werasc; /* word erase */


   char t_lnextc; /* literal next character */
};

The characters are mapped to members of the c_cc field of the termios structure as follows:

IOCTLS

ttcompat responds to the following ioctl calls. All others are passed to the module below.

TIOCGETP

TIOCEXCL

TIOCNXCL

TIOCSETP

TIOCSETN

TIOCHPCL

TIOCFLUSH

TIOCSBRK

TIOCCBRK

TIOCSDTR

TIOCCDTR

TIOCSTOP

TIOCSTART

TIOCGETC

TIOCSETC

TIOCLGET

TIOCLBIS

TIOCLBIC

TIOCLSET

TIOCGLTC

TIOCSLTC

FIORDCHK

FIONREAD

The following ioctls are returned as successful for the sake of compatibility. However, nothing significant is done (that is, the state of the terminal is not changed in any way, and no message is passed through to the underlying tty driver).

DIOCSETP
DIOCSETP
DIOCGETP
LDCLOSE
LDCHG
LDOPEN
LDGETT
LDSETT
TIOCGETD
TIOCSETD

The following old ioctls are not supported by ttcompat, but are supported by Solaris tty drivers. As with all ioctl not otherwise listed in this documentation, these are passed through to the underlying driver and are handled there.

TIOCREMOTE
TIOCGWINSZ
TIOCSWINSZ

The following ioctls are not supported by ttcompat, and are generally not supported by Solaris tty drivers. They are passed through, and the tty drivers return EINVAL.

LDSMAP
LDGMAP
LDNMAP
TIOCNOTTY
TIOCOUTQ

(Note: LDSMAP, LDGMAP, and LDNMAP are defined in <sys/termios.h>.)

SEE ALSO

ioctl(2), termios(3C), termio(4I), ldterm(4M)