Fix a bug in the built-in echo in /bin/sh reported in private mail by
Oguz <oguzismailuysal@gmail.com>

If echo detects an I/O error, it does exit(1) (that's fine) but then
the next echo also does exit(1) even without any errors of its own,
and every following echo writing to stdout does the same thing.

eg:

echo foo >&- ; echo $?; echo $?; ( echo $( echo $?; echo $?) ; echo $? )
1
1
1 1
1

The first echo writes nothing (stdout is closed) but does exit(1).
The second echo writes "1" (correct, the exit status of the previous
echo) and should exit(0) - but doesn't. This pattern continues...

While here, conform to the POSIX requirement on echo (and many other
standard utilities, but definitely not all) that when the utility
does exit(>0) a message must be written to stderr (and vice versa
in many cases). Our echo (as shown above) did the exit(1) part
when it detected the I/O error, but no message is sent to stderr.
Fix that while we're here.

Similar changes are required for /bin/echo (coming soon), and
/usr/bin/printf (which is also the sh builtin printf) - except
currently that one kind of conforms, as it ignores errors writing
to stdout (as do large numbers of other utilities). For many
programs that's kind of acceptable, but where the sole purpose of
the program is to write to stdout, it really isn't. Also to be
fixed soon.

branches: 1.15.6; 1.15.12;
Make arg parsing in kill POSIX compatible with POSIX (XBD 2.12) by
parsing the way getopt(3) would, if only it could handle the (required)
-signumber and -signame options. This adds two "features" to kill,
-ssigname and -lstatus now work (ie: one word with all of the '-', the
option letter, and its value) and "--" also now works (kill -- -pid1 pid2
will not attempt to send the pid1 signal to pid2, but rather SIGTERM
to the pid1 process group and pid2). It is still the case that (apart
from --) at most 1 option is permitted (-l, -s, -signame, or -signumber.)

Note that we now have an ambiguity, -sname might mean "-s name" or
send the signal "sname" - if one of those turns out to be valid, that
will be accepted, otherwise the error message will indicate that "sname"
is not a valid signal name, not that "name" is not. Keeping the "-s"
and signal name as separate words avoids this issue.

Also caution: should someone be weird enough to define a new signal
name (as in the part after SIG) which is almost the same name as an
existing name that starts with 'S' by adding an extra 'S' prepended
(eg: adding a SIGSSYS) then the ambiguity problem becomes much worse.
In that case "kill -ssys" will be resolved in favour of the "-s"
flag being used (the more modern syntax) and would send a SIGSYS, rather
that a SIGSSYS. So don't do that.

While here, switch to using signalname(3) (bye bye NSIG, et. al.), add
some constipation, and show a little pride in formatting the signal names
for "kill -l" (and in the usage when appropriate -- same routine.) Respect
COLUMNS (POSIX XBD 8.3) as primary specification of the width (terminal width,
not number of columns to print) for kill -l, a very small value for COLUMNS
will cause kill -l output to list signals one per line, a very large
value will cause them all to be listed on one line.) (eg: "COLUMNS=1 kill -l")

TODO: the signal printing for "trap -l" and that for "kill -l"
should be switched to use a common routine (for the sh builtin versions.)

All changes of relevance here are to bin/kill - the (minor) changes to bin/sh
are only to properly expose the builtin version of getenv(3) so the builtin
version of kill can use it (ie: make its prototype available.)

branches: 1.14.8;
Avoid warning by using gcc'ism

output.c output.h: expose OUTPUT_ERR (flag for an exposed flags variable)
bltin.h: support ferror()
echo.c: use ferror() to fail on output write errors

Another piece of PR bin/39574.

* define SHELL_BUILTIN, which other headers may use to hide some of their
symbols if appropriate. For example, error.h will use it to hide
declarations that should not be seen by external builtins such as printf.
* The shell's outfmt() function returns void, but the standard fprintf()
function returns int. Similarly for several other functions that are
redefined via macros in bltin.h. Add a _RETURN_INT macro to do the
necessary conversion.
* Delete some declarations that appear in error.h.
* Add comments on some #else/#endif lines.

branches: 1.11.16;
Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22249, verified by myself.

Fixes from David Laight:
- ansification
- format of output of jobs command (etc)
- job identiers %+, %- etc
- $? and $(...)
- correct quoting of output of set, export -p and readonly -p
- differentiation between nornal and 'posix special' builtins
- correct behaviour (posix) for errors on builtins and special builtins
- builtin printf and kill
- set -o debug (if compiled with DEBUG)
- cd src obj (as ksh - too useful to do without)
- unset -e name, remove non-readonly variable from export list.
(so I could unset -e PS1 before running the test shell...)

Fix compiler warnings.

PR/2808: Add a definition for warnx() (from FreeBSD; currently unused)

branches: 1.7.6;
convert to new RCS id conventions.

Add RCS ids.

sync with 4.4lite

Add RCS identifiers.

changed "Id" to "Header" for rcsids

added rcs ids to all files

branches: 1.1.1;
Initial revision

branches: 1.14.6;
Remove workaround for ancient HTML generation code.

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22249, verified by myself.

Generate <>& symbolically. I'm avoiding .../dist/... directories for now.

Punctuation nit.

Whitespace nits.

More and more .Os cleanups. .Os is defined in the tmac.doc-common file,
so we shouldn't override it with versions in the manpages. Many more to
come.

PR/2808: Use .Nm macro properly. (from FreeBSD)

branches: 1.7.6;
convert to new RCS id conventions.

Add RCS ids.

sync with 4.4lite

Add RCS identifiers.

changed "Id" to "Header" for rcsids

added rcs ids to all files

branches: 1.1.1;
Initial revision

Fix a bug in the built-in echo in /bin/sh reported in private mail by
Oguz <oguzismailuysal@gmail.com>

If echo detects an I/O error, it does exit(1) (that's fine) but then
the next echo also does exit(1) even without any errors of its own,
and every following echo writing to stdout does the same thing.

eg:

echo foo >&- ; echo $?; echo $?; ( echo $( echo $?; echo $?) ; echo $? )
1
1
1 1
1

The first echo writes nothing (stdout is closed) but does exit(1).
The second echo writes "1" (correct, the exit status of the previous
echo) and should exit(0) - but doesn't. This pattern continues...

While here, conform to the POSIX requirement on echo (and many other
standard utilities, but definitely not all) that when the utility
does exit(>0) a message must be written to stderr (and vice versa
in many cases). Our echo (as shown above) did the exit(1) part
when it detected the I/O error, but no message is sent to stderr.
Fix that while we're here.

Similar changes are required for /bin/echo (coming soon), and
/usr/bin/printf (which is also the sh builtin printf) - except
currently that one kind of conforms, as it ignores errors writing
to stdout (as do large numbers of other utilities). For many
programs that's kind of acceptable, but where the sole purpose of
the program is to write to stdout, it really isn't. Also to be
fixed soon.

branches: 1.14.62; 1.14.68;
output.c output.h: expose OUTPUT_ERR (flag for an exposed flags variable)
bltin.h: support ferror()
echo.c: use ferror() to fail on output write errors

Another piece of PR bin/39574.

use __RCSID()

branches: 1.12.10; 1.12.16;
remove obsolete register declarations

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22249, verified by myself.

Spell output with two ts.

Fixes from David Laight:
- ansification
- format of output of jobs command (etc)
- job identiers %+, %- etc
- $? and $(...)
- correct quoting of output of set, export -p and readonly -p
- differentiation between nornal and 'posix special' builtins
- correct behaviour (posix) for errors on builtins and special builtins
- builtin printf and kill
- set -o debug (if compiled with DEBUG)
- cd src obj (as ksh - too useful to do without)
- unset -e name, remove non-readonly variable from export list.
(so I could unset -e PS1 before running the test shell...)

Fix problems that gcc -Wall found (from Todd Miller, OpenBSD)

branches: 1.7.6;
convert to new RCS id conventions.

Add RCS ids.

sync with 4.4lite

Add RCS identifiers.

changed "Id" to "Header" for rcsids

added rcs ids to all files

branches: 1.1.1;
Initial revision