abs(pid)) and indicate that -- is (strictly) needed if the first pid arg
(there often is only one) is negative - though this implementation works
without it if a signal to send has been explicitly given, but whereas
'kill 1234" is valid (send SIGTERM to pid 1234) "kill -1234" will generate
a usage error from the attempt to send signal 1234 to nothing, to send
SIGTERM to pgrp 1234 it needs to be "kill -- -1234" (or "kill -s term -1234").
While here do a couple of markup improvements, and allow for the
possibility that users might be running the builtin kill from some
shell other than csh or sh.
That means we cannot use (pid_t)-1 as an error indicator, as that's a
valid pid to use (described as working in kill(1) - yet it wasn't working
in /bin/kill (nor sh's builtin kill, which is essentially the same code).
This is even required to work by POSIX.
So change processnum() (the parser/validator for the pid args) to take
a pointer to a pid_t and return the pid that way, leaving the return value
of the (now int) function to indicate just ok/error. While here, fix
the validation a little ('' is no longer an accepted alias for 0) and in
case of an error from kill(2) have the error message indicate whether the
kill was targeted at a pid of a pgrp.
environment, rather than the nicer layout that is normally used.
Note this applies to /bin/kill only, the builtin kill in sh uses its
"posix" option for the same purpose, the one in csh only ever uses
POSIX format.
kill and sh were merged so that the shell (for trap -l) and
kill (for kill -l) can use the same routine, and site that function
in the shell, rather than in kill (use the code that is in kill as
the basis for that routine). This allows access to sh internals,
and in particular to the posix option, so the builtin kill can
operate in posix mode where the standard requires just a single
character (space of newline) between successive signal names (and
we prefer nicely aligned columns instead)..
In a SMALL shell, use the ancient sh printsignals routine instead,
it is smaller (and very much dumber).
/bin/kill still uses the routine that is in its source, and is
not posix compliant. A task for some other day...
and one in (the included from bin/kill) kill.c and use just
the one in kill.c (which is amended slightly so it can work
the way that trap.c needs it to work). This one is chosen as
it was a much nicer implementation, and because while kill is
always built into the shell, kill also exists without the shell.
Leave the old implementation #if 0'd in trap.c (but updated to
match the calling convention of the one in kill.c) - for now.
Delete references of sys_signame[] from sh/trap.c and along with
that several uses of NSIG (unfortunately, there are still more)
and replace them with the newer libc functional interfaces.
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.)
Unfortunately only the source code for the compiler is present for that
release. The v2 archive is missing the manuals & only contains a some of the
commands.
Switch to v3 and reference manual category eight.
If stdout is a tty, use vis(3) to print any filenames to prevent garbage
from being printed if the filename contains control- or other non-printable
characters.
While here, sprinkle some EXIT_FAILURE and NOTREACHED where appropriate.
- 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...)
christos