#include <sys/stream.h> #include <sys/stropts.h> #include <sys/ttold.h> #include <sys/ttcompat.h> #include <sys/filio.h>
ioctl( fd, I_PUSH, "ttcompat");
ttcompat is a STREAMS module that translates the ioctl calls supported by the older Version 4BSD, and XENIX terminal drivers into the ioctl calls supported by the termio interface (see termio(7I) ). 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>:
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, and reflect the values in the c_cflag field of the termios structure. 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 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:
- sg_flags
- c_oflag
- BS1
- BS1
- FF1
- VT1
- CR1
- CR2
- CR2
- CR3
- CR3
- not supported
- TAB1
- TAB1
- TAB2
- TAB2
- XTABS
- TAB3
- NL1
- ONLRET|CR1
- NL2
- NL1
If previous TIOCLSET or TIOCLBIS ioctl calls have not selected LITOUT or PASS8 mode, and if RAW mode is not selected, then 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.
Parity is not to be generated on output or checked on input. The character size is set to CS8 and the flag is cleared in the c_cflag field of the termios structure.
Even parity characters are to be generated on output and accepted on input. The flag is set in the c_iflag field of the termios structure, the character size is set to CS7 and the flag is set in the c_cflag field of the termios structure.
Odd parity characters are to be generated on output and accepted on input. The flag is set in the c_iflag field, the character size is set to CS7 and the flags are set in the c_cflag field of the termios structure.
Even parity characters are to be generated on output and characters of either parity are to be accepted on input. The flag is cleared in the c_iflag field, the character size is set to CS7 and the flag is set in the c_cflag field of the termios structure.
The RAW flag disables all output processing (the OPOST flag in the c_oflag field, and the XCASE flag in the c_lflag 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). 8 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_lflag field of the termios structure.
The CRMOD
flag turns input RETURN
characters into NEWLINE
characters,
and output and echoed NEWLINE
characters to be output as a 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:
in c_iflag field
- sg_flags
- flags in termios structure
- CBREAK
- complement of ICANON in c_lflag field
- ECHO
- ECHO in c_lflag field
- TANDEM
- IXOFF
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, specifying flags
supported by the new 4BSD
terminal interface. Most of these flags are
directly mapped to flags in the termios structure:
in the c_lflag field
- local flags
- flags in termios structure
- LCRTBS
- not supported
- LPRTERA
- ECHOPRT in the c_lflag field
- LCRTERA
- ECHOE in the c_lflag field
- LTILDE
- not supported
- LTOSTOP
- TOSTOP in the c_lflag field
- LFLUSHO
- FLUSHO in the c_lflag field
- LNOHANG
- CLOCAL in the c_cflag field
- LCRTKIL
- ECHOKE in the c_lflag field
- LCTLECH
- CTLECH in the c_lflag field
- LPENDIN
- PENDIN in the c_lflag field
- LDECCTQ
- complement of IXANY in the c_iflag field
- LNOFLSH
- NOFLSH
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:
- ltchars
- c_cc index
- t_suspc
- VSUSP
- t_dsuspc
- VDSUSP
- t_rprntc
- VREPRINT
- t_flushc
- VDISCARD
- t_werasc
- VWERASE
- t_lnextc
- VLNEXT
ttcompat responds to the following ioctl calls. All others are passed to the module below.
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).
TIOCSETD LDOPEN TIOCGETD LDCLOSE DIOCSETP LDCHG DIOCSETP LDSETT DIIOGETP LDGETT