ttcompat(7) UNIX System V ttcompat(7)
NAME
ttcompat - V7, 4BSD and XENIX STREAMS compatibility module
SYNOPSIS
#include <sys/stream.h>
#include <sys/stropt.h>
#include <sys/ttcompat.h>
#include <sys/ttold.h>
ioctl(fd, IPUSH, "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(7)]. 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
ccflag field are not supported, the functions provided by the sgispeed
and sgospeed 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
struct sgttyb {
char sgispeed;
char sgospeed;
char sgerase;
char sgkill;
int sgflags;
};
The sgispeed and sgospeed fields describe the input and output speeds
of the device, and reflect the values in the ccflag field of the termios
structure. The sgerase and sgkill fields of the argument structure
specify the erase and kill characters respectively, and reflect the
values in the VERASE and VKILL members of the ccc field of the termios
structure.
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The sgflags 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
coflag field of the termios structure. Other delay mappings are
performed as follows:
sgflags coflag
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, the ISTRIP flag is set in
the ciflag 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 ccflag
field of the termios structure.
Even parity characters are to be generated on output and accepted on
input;
the flag is set in the ciflag field of the termios structure, the
character size is set to CS7 and the flag is set in the ccflag field
of the termios structure.
Odd parity characters are to be generated on output and accepted on
input; the flag is set in the
ciflag field, the character size is set to CS7 and the and flags are
set in the ccflag 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 ciflag field, the character size is set to
CS7 and the flag is set in the ccflag field of the termios structure.
The RAW flag disables all output processing (the OPOST flag in the
coflag field, and the XCASE flag in the clflag field, are cleared in
the termios structure) and input processing (all flags in the ciflag
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
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ttcompat(7) UNIX System V ttcompat(7)
and generated on output; the character size is set to CS8 and the PARENB
and PARODD flags are cleared in the ccflag field of the termios
structure. The signal-generating and line-editing control characters are
disabled by clearing the ISIG and ICANON flags in the clflag 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 ciflag field, and the OPOST and ONLCR
flags in the coflag 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
ciflag 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
coflag 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 clflag field).
Other flags are directly mapped to flags in the termios structure:
sgflags flags in termios structure
CBREAK complement of ICANON in clflag field
ECHO ECHO in clflag field
TANDEM IXOFF in ciflag field
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
struct tchars {
char tintrc; /* interrupt */
char tquitc; /* quit */
char tstartc; /* start output */
char tstopc; /* stop output */
char teofc; /* end-of-file */
char tbrkc; /* input delimiter (like nl) */
};
XENIX defines the tchar structure as tc. The characters are mapped to
members of the ccc field of the termios structure as follows:
tchars ccc index
tintrc VINTR
tquitc VQUIT
tstartc VSTART
tstopc VSTOP
teofc VEOF
tbrkc 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:
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local flags flags in termios structure
LCRTBS not supported
LPRTERA ECHOPRT in the clflag field
LCRTERA ECHOE in the clflag field
LTILDE not supported
LTOSTOP TOSTOP in the clflag field
LFLUSHO FLUSHO in the clflag field
LNOHANG CLOCAL in the ccflag field
LCRTKIL ECHOKE in the clflag field
LCTLECH CTLECH in the clflag field
LPENDIN PENDIN in the clflag field
LDECCTQ complement of IXANY in the ciflag field
LNOFLSH NOFLSH in the clflag field
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 tsuspc; /* stop process signal */
char tdsuspc; /* delayed stop process signal */
char trprntc; /* reprint line */
char tflushc; /* flush output (toggles) */
char twerasc; /* word erase */
char tlnextc; /* literal next character */
};
The characters are mapped to members of the ccc field of the termios
structure as follows:
ltchars ccc index
tsuspc VSUSP
tdsuspc VDSUSP
trprntc VREPRINT
tflushc VDISCARD
twerasc VWERASE
tlnextc VLNEXT
IOCTLS
ttcompat responds to the following ioctl calls. All others are passed to
the module below.
TIOCGETP The argument is a pointer to an sgttyb structure. The
current terminal state is fetched; the appropriate characters
in the terminal state are stored in that structure, as are
the input and output speeds. The values of the flags in the
sgflags field are derived from the flags in the terminal
state and stored in the structure.
TIOCEXCL Set ``exclusive-use'' mode; no further opens are permitted
until the file has been closed.
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TIOCNXCL Turn off ``exclusive-use'' mode.
TIOCSETP The argument is a pointer to an sgttyb structure. The
appropriate characters and input and output speeds in the
terminal state are set from the values in that structure, and
the flags in the terminal state are set to match the values
of the flags in the sgflags field of that structure. The
state is changed with a TCSETSF ioctl so that the interface
delays until output is quiescent, then throws away any unread
characters, before changing the modes.
TIOCSETN The argument is a pointer to an sgttyb structure. The
terminal state is changed as TIOCSETP would change it, but a
TCSETS ioctl is used, so that the interface neither delays
nor discards input.
TIOCHPCL The argument is ignored. The HUPCL flag is set in the
ccflag word of the terminal state.
TIOCFLUSH The argument is a pointer to an int variable. If its value
is zero, all characters waiting in input or output queues are
flushed. Otherwise, the value of the int is treated as the
logical OR of the FREAD and FWRITE flags defined by
<sys/file.h> ; if the FREAD bit is set, all characters
waiting in input queues are flushed, and if the FWRITE bit is
set, all characters waiting in output queues are flushed.
TIOCBRK The argument is ignored. The break bit is set for the
device.
TIOCCBRK The argument is ignored. The break bit is cleared for the
device.
TIOCSDTR The argument is ignored. The Data Terminal Ready bit is set
for the device.
TIOCCDTR The argument is ignored. The Data Terminal Ready bit is
cleared for the device.
TIOCSTOP The argument is ignored. Output is stopped as if the STOP
character had been typed.
TIOCSTART The argument is ignored. Output is restarted as if the START
character had been typed.
TIOCGETC The argument is a pointer to a tchars structure. The current
terminal state is fetched, and the appropriate characters in
the terminal state are stored in that structure.
TIOCSETC The argument is a pointer to a tchars structure. The values
of the appropriate characters in the terminal state are set
from the characters in that structure.
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TIOCLGET The argument is a pointer to an int. The current terminal
state is fetched, and the values of the local flags are
derived from the flags in the terminal state and stored in
the int pointed to by the argument.
TIOCLBIS The argument is a pointer to an int whose value is a mask
containing flags to be set in the local flags word. The
current terminal state is fetched, and the values of the
local flags are derived from the flags in the terminal state;
the specified flags are set, and the flags in the terminal
state are set to match the new value of the local flags word.
TIOCLBIC The argument is a pointer to an int whose value is a mask
containing flags to be cleared in the local flags word. The
current terminal state is fetched, and the values of the
local flags are derived from the flags in the terminal state;
the specified flags are cleared, and the flags in the
terminal state are set to match the new value of the local
flags word.
TIOCLSET The argument is a pointer to an int containing a new set of
local flags. The flags in the terminal state are set to
match the new value of the local flags word.
TIOCGLTC The argument is a pointer to an ltchars structure. The
values of the appropriate characters in the terminal state
are stored in that structure.
TIOCSLTC The argument is a pointer to an ltchars structure. The
values of the appropriate characters in the terminal state
are set from the characters in that structure.
FIORDCHK FIORDCHK returns the number of immediately readable
characters. The argument is ignored.
FIONREAD FIONREAD returns the number of immediately readable
characters in the int pointed to by the argument.
LDSMAP Calls the function emsetmap (tp, mp) if the function is
configured in the kernel.
LDGMAP Calls the function emgetmap (tp, mp) if the function is
configured in the kernel.
LDNMAP Calls the function emunmap (tp, mp) if the function is
configured in the kernel.
The following ioctls are returned as successful for the sake of
compatibility. However, nothing significant is done (i.e., the state of
the terminal is not changed in any way).
TIOCSETD LDOPEN
TIOCGETD LDCLOSE
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ttcompat(7) UNIX System V ttcompat(7)
DIOCSETP LDCHG
DIOCSETP LDSETT
DIIOGETP LDGETT
SEE ALSO
ioctl(2), termios(2), termio(7), ldterm(7)
NOTES
TIOCBRK and TIOCCBRK should be handled by the driver. FIONREAD and
FIORDCHK are handled in the stream head.
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