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NAME
setterm - build a Stream on a tty line
SYNOPSIS
setterm [ -t TERMNAME ]
setterm -x NAME
setterm -v
AVAILABILITY
SUNWale
DESCRIPTION
Setterm is used to build a STREAMS configuration on a tty
line. It expects to be called with stdin, stdout, and
stderr all attached to a terminal line, though it will usu-
ally work if only standard input is connected to a terminal
line. It will normally be called with some kind of line
discipline already pushed onto the line, since getty needs
to push a line discipline that can be used by login.
If invoked with no arguments, setterm looks at the user's
environment for a $TERM variable. If none is found, setterm
exits, since it needs the $TERM information to do any
further processing. If the -t option is given with an argu-
ment, the next argument (TERMNAME) is taken to be the name
of a terminal type. The terminal name is looked up in the
terminfo(4) database and the field "devt" (if one exists) is
extracted from the entry. If there is no "devt" field, the
terminal is assumed to be ASCII, requiring no additional
processing, and setterm will then print the message "Device
is ASCII" and exit.
Setterm then runs the commands in its configuration file
associated with the "devt" field in the terminfo(4) entry.
If the -t option is not given, or if there are no command
line arguments, then it is an error for no entry to match.
In that case setterm exits with an error message.
If the -x option is given, the following argument (NAME) is
taken to be a "devt" field appearing in the configuration
file. The terminfo(4) entry is not looked up, but the argu-
ment is used instead. The matching entry in the configura-
tion file is executed unconditionally; therefore the -x
option should be used with caution. The -x option is most
useful for testing modules, and in switching between confi-
gurations dynamically, or for overriding the default entry
for a particular "devt" type. The following "devt" fields
are registered in each locale's configuration file:
Chinese/PRC locale (locale name = "zh")
GenericEUC|EUC For EUC terminal
ASCII For ASCII terminal
Error For recovery from error in set-
term execution
sane For reset of STREAMS
Chinese/Taiwan locale (locale name = "zh_TW" / "zh_TW.BIG5")
big5 For Big-5 terminal
GenericEUC|EUC For EUC terminal
ASCII For ASCII terminal
Error For recovery from error in set-
term execution
sane For reset of STREAMS
Japanese locale (locale name = "ja")
JapanPCK|PCK|JapanSJIS|SJIS
For PCK (Shift-JIS) terminal
JapanNewJIS7|NewJIS7 For 7Bit new JIS terminal
JapanOldJIS7|OldJIS7 For 7Bit old JIS terminal
JapanNewJIS8|NewJIS8 For 8Bit new JIS terminal
JapanOldJIS8|OldJIS8 For 8Bit old JIS terminal
GenericEUC|JapanEUC|EUC For EUC terminal
ASCII For ASCII terminal
Error For recovery from error in set-
term execution
sane For reset of STREAMS
Japanese locale (locale name = "ja_JP.PCK")
JapanPCK|PCK|JapanSJIS|SJIS
For PCK (Shift-JIS) terminal
JapanNewJIS7|NewJIS7 For 7Bit new JIS terminal
JapanOldJIS7|OldJIS7 For 7Bit old JIS terminal
JapanNewJIS8|NewJIS8 For 8Bit new JIS terminal
JapanOldJIS8|OldJIS8 For 8Bit old JIS terminal
GenericEUC|JapanEUC|EUC For EUC terminal
ASCII For ASCII terminal
Error For recovery from error in set-
term execution
sane For reset of STREAMS
Korean locale (locale name = "ko")
KoreanPACK|PACK For Packed code terminal (KS C
5601-1987)
KoreanJOHAP|JOHAP For Combination code terminal
(KS C 5601-1992)
GenericEUC|EUC For EUC (Wansung) terminal
ASCII For ASCII terminal
Error For recovery from error in
setterm execution
sane For reset of STREAMS
Korean locale (locale name = "ko.UTF-8")
U8|u8|UTF-8|utf-8 For UTF-8 (of KS C 5700) termi-
nal
KoreanU8EUC|KU8EUC For EUC (Wansung) terminal
KoreanU8JOHAP|KU8JOHAP For Combination code terminal
(KS C 5601-1992)
GenericEUC|EUC For EUC (Wansung) terminal
without UTF-8 code conversion
ASCII For ASCII terminal
Error For recovery from error in set-
term execution
sane For reset of STREAMS
The -v option is used to verify that the contents of the
configuration file are correct. It prints debugging output
for each entry in the configuration file, but does not per-
form any of the actions. It is only used for syntactic
verification of configurations.
If the "devt" field is present for the given terminal, its
value is used in searching the configuration file for an
appropriate entry. The line in the configuration file is
parsed and the actions carried out by setterm.
If the user's environment contains the variable $SETTLIB, it
is taken to be the pathname of a file to use as the confi-
guration file instead of the default configuration file,
allowing per-user customization.
For languages requiring dictionary modules or other special-
ized processing capability the "run" command can be used to
send appropriate ioctl(2) commands and do special purpose
(i.e. language dependent) processing once the Stream has
been built, or appropriate modules pushed. Programs run via
the "run" command for this purpose, generally residing in
the setterm library, are known as initialization programs.
As distributed, the setterm configuration file comes with a
few examples, and the format should be self-explanatory.
Lines beginning with "#" (in the first column only) are
ignored as comments.
COMMAND LANGUAGE
The setterm command language is very simple. Each entry
occupies a single logical line in the configuration file.
Newlines may be escaped with a backslash so that entries may
be spread over several physical lines for ease of editing.
Each entry consists of an identifying word (which normally
matches a "devt" entry of the terminfo(4) database) and a
list of actions. Each action is separated by whitespace
(spaces, tabs, or escaped newlines). A "word" is defined as
a block of alpha-numeric or special printing characters con-
taining no whitespace or control characters.
An action consists of a command word, which may be followed
by a single argument word. The argument word is separated
from the command word by either a comma or whitespace.
An argument word must not contain any spaces or tabs, but
may have internal delimiters, such as colons and commas.
For example:
Acceptable: A=ldterm:eldterm,ld0:eld0
Unacceptable: A = ldterm: eldterm , ld0:eld0
The following commands are recognized. "NAME", "NAMELIST",
"MOD1", and "MOD2", indicate the names of modules; "NAMEL-
IST" indicates one or more of module names separated (with
no space) by a vertical bar ("|" symbol); "CMD" indicates a
shell command line; "VAR" indicates a single letter variable
name from "A" through "F"; "WORDLIST" indicates a special
wordlist for the "select" command:
cmd Arguments Action(s)
pop none pop one module
popto NAMELIST pop until it encounters one of
modules in NAMELIST or there is no
more to pop
popall none pop all modules
throw none save termio(7) settings
catch none restore termio(7) settings
push NAME push module name
run { CMD } run command line between {}
set VAR set VAR to name of top module
if VAR=NAME?MOD1:MOD2 if the value of VAR is equal
to NAME, then push MOD1, else
push MOD2
test VAR=NAME set VAR to
NAME if the module "NAME" is in the
STREAM
select VAR=WORDLIST test "VAR" against the left
word of each pair in "WORDLIST";
push the first right word that matches
Some special words are recognized for the "if", "test" and
"select" commands. These words are:
END stop processing and exit
NUL do nothing
POP pop a module rather than pushing
ELSE as first of a pair in a WORDLIST,
match any value including a NULL string
The argument to an "if" command, as shown above, has the
following meaning: if the value of the given variable
matches the literal module name "NAME", then the action
"MOD1" is taken, otherwise the action "MOD2" is taken. If
no alternate action is desired, the colon and "MOD2" may be
elided. The action for a module name is, by default, to
push it. If the module name is one of the special names,
then the action associated with the special name is taken.
An "ELSE" keyword may not appear in a "test" or "if" com-
mand. The "END" keyword may not appear as the value to test
a variable against, but only as an action to take on a
match.
The "WORDLIST" for a "select" command is a variable name, an
equal sign, then a list of word pairs of the form
"WORD.WORD". Each word pair is separated from the others by
a comma. Thus, a whole "select" command might look like:
select A=eld0:ld0epld:ppld,ELSE:ld0
The "ELSE" keyword cannot, of course be used as the right
word of a pair, nor can the "END" keyword be used as the
left word of a pair; "NUL" can be either.
The "run" command is exceptional in that its argument may
contain spaces between the curly braces. An action for a
"run" command might be:
run { /usr/share/lib/setterm/a_prog an_arg }
Commands invoked through the "run" command should reside in
the directory /usr/share/lib/setterm, though this is not
required. They should not require too many arguments as
they are intended to be very specialized. In general, they
perform any device- or language-dependent processing on
behalf of setterm, which has no language-dependent process-
ing capability.
If setterm was invoked with the -t option, then programs
invoked through the "run" command will have their environ-
ment $TERM variable replaced with the terminal name indi-
cated in the argument to the -t option.
The "throw" command saves the termio(7) settings of the tty.
They can be restored (presumably after the line discipline
or other module has changed) through the "catch" command.
These are useful for switching line disciplines, when both
the old and new line disciplines support, as a minimum, the
termio(7) interface. If a "catch" is done without a prior
"throw", then the command line "stty sane" will be done
instead of the "catch" (useful for restoring badly messed up
Streams); thus a "catch" with no throw is equivalent to
"run{stty sane}". Two "throw" cannot be done without a
"catch" between them.
EXAMPLES
The following example shows how a complete entry might look
in the configuration file:
#
# Japanese 7-bit JIS terminal
JapanJIS7|JIS7throw\
popto zs|mcp|mti|ptem\
push jconv7\
push ldterm\
push ttcompat\
catch
#
This entry can be invoked with,
% setterm -x JIS7
As noted, the escaped newlines are necessary since the entry
must be all on a single logical line. Escaped newlines are
treated as single space characters.
The "devt" label in the configuration file may optionally be
a list of words separated (with no spaces) by a vertical bar
("|" symbol). In this case, each one is scanned by setterm
for a match when looking for an entry in the file; if any
word of the "|" separated list matches, that entry is used.
There is an extra variable, "T", which when set with the set
command, takes on a generic device name. When this variable
is set, a call to ttyname(3) on file descriptor zero is
issued by setterm. The resulting device name is stripped of
any trailing ASCII digits (i.e., 0-9), and the result
becomes the value of the "T" variable. This is useful if
specialized processing is necessary for different device
types or drivers, for example if the console requires
special-purpose processing. Actual device names, such as
"/dev/tty33" are turned into names such as "/dev/tty".
Beware that names containing no trailing digits cannot be
stripped of them, so that "/dev/console" remains just that.
An example of usage might be:
set T select T=/dev/console:this,/dev/tty:that,ELSE:other
LIMITATIONS
Currently, the maximum size of a single "action" entry is
limited to 2047 bytes. The number of items in a "select"
list is limited to 30. Setterm unfortunately cannot be used
to build multiplexing configurations. The "run" command may
help where multiplexing configurations are required. Set-
term will neither save nor restore termio(7) settings,
except through "throw" and "catch".
Error reporting is minimal; all errors are fatal. Inability
to pop a module is not an error, since it may signal the
"bottom" of the STREAM.
The configuration file is scanned sequentially, and only the
first entry found for a particular "devt" is executed.
CAVEATS
Since all errors are fatal, the user could be left with an
extremely "raw" terminal configuration, or worse, with a
completely useless configuration from which there is no
escape except by logging out (if any input is possible at
all!). "Throw", "catch", and tests for existence of a rea-
sonable top-level module should help reduce these possibili-
ties. Rigorous testing of new entries under varying condi-
tions is recommended. It is also recommended that a "sane"
entry of some type be inserted into the configuration file
for use with the -x option.
Setterm uses its standard input file (file descriptor zero)
for all ioctl(2) calls to the terminal. Therefore, if the
terminal should hang (for example if all modules have been
popped but it is impossible to push anything, or in the
event of a module hangup or failure) it is possible to run
setterm from another terminal (assuming appropriate permis-
sions) with standard input redirected to the errant terminal
line. For example, if tty12 is hung due to a module prob-
lem, "setterm-x ... < /dev/tty12" should clear the problem.
Beware of infinite recursion when calling setterm recur-
sively (i.,e., when "run { setterm ... }" from within an
entry; setterm cannot detect infinite recursion.
FILES
/usr/share/lib/setterm setterm library
/usr/share/lib/setterm/locale/conf.file
default configuration file
/usr/share/lib/setterm/NOTES
explanation and notes on format
SEE ALSO
getty(1M), tic(1M), terminfo(4), streamio(7), termio(7)
Documentation on various local modules
BUGS
A missing "}" to a "run" command may not be caught by the
parser, which is relatively crude. This can result in bad
arguments to commands, without the syntax error being
caught.
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