aliases, to actually do what it was supposed to do, and not just
come close by accident. (How broken this was, while still seeming
to work perfectly most of the time was truly amazing!)
This corrects the behaviour of an alias defined with a blank char
as the last of its value, to correctly do an alias lookup on the
word that follows the alias.
cope with the changes made in the previous revision, in an
attempt to avoid bit rot.
Untested (uncompiled) - though it should work.
NFC: this change doesn't get compiled, let alone used.
(a normal builtin, though those are not genrally an issue for
this problem, or a special builtin that has been prefixed by "command")
make sure that we discard any pending input that might have been
queued up, but not yet processed.
We had the mechanism to fix this from when expansion of PS1 etc
was added (which has a similar problem to deal with) - all taken
from FreeBSD - but did not bother to use it here until now...
This fixes an error detected by newly added ATF tests of the eval
builtin, where
eval 'syntax error
another command'
would go ahead and evaluate "another command" which should not
happen (note: only when there was a \n between the two).
Standard C says that free should be a no-op for a NULL pointer, so
we don't need an extra function to do this.
While here, add an XXX about a wrong sounding comment
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...
The SYNOPSIS for "readonly -q" cannot have the -q be
optional ... Also harmonise the output appearance with
that of the export command.
wiz: have at it...
readonly -q VAR...
readonly -p VAR...
export -q [-x] VAR...
export -p [-x] VAR...
all available only in !SMALL shells - and while here, limit
"export -x" to full sized shells as well.
Also, do a better job of arg checking and validating of the
export and readonly commands (which is really just one built-in)
and of issuing error messages when something bogus is detected.
Since these commands are special builtin commands, any error
causes shell exit (for non-interactive shells).
var=foo; readonly var=new
now fails.
If var was already set, an attempt to make it readonly, and assign it
a new value at the same time, failed - the readonly flag was set too soon.
Pointed out by Martijn Dekker (thanks).
Also, while here, add a couple of comments.
Implement parameter and arithmetic expansion of $ENV
before using it as the name of a file from which to
read startup commands for the shell. This continues
to happen for all interactive shells, and non-interactive
shells for which the posix option is not set (-o posix).
On any actual error, or if an attempt is made to use
command substitution, then the value of ENV is used
unchanged as the file name.
The expansion complies with POSIX XCU 2.5.3, though that
only requires parameter expansion - arithmetic expansion
is an extension (but for us, it is much easier to do, than
not to do, and it allows some weird stuff, if you're so
inclined....) Note that there is no ~ expansion (use $HOME).
update to mkinit.sh (to 1.10).
Or more correctly, revert & fix - turns out that there was an off by one
(failure to adjust for other changes -- in a value printed by debug mode
trace output).
NFC.
uses printf for simplicity).
This script runs using the build host's shell, and echo, and so must
deal with all of the absurdity that different versions of echo dumb
upon us.
This is the underlying cause of the linux build failure that gson@ reported.
some versions of liux) - DEBUG mode change: Delete a (relatively new)
trace point (temporarily anyway) which mkinit (a script run using the
host's /bin/sh) apparently cannot handle correctly on (some release of)
linux (it is fine with the NetBSD shell).
I don't know which linux version has a shell with this problem
(or whether it is a mkinit issue that only works by fluke on NetBSD)
Problem reported by gson@
were added to sh ... in other shells, setting such a variable
(for most of them) causes it to lose its special properties,
and act the same as any other variable. I had assumed that
was just implementor laziness... I was wrong.
From now on the NetBSD shell will act like the others, and if vars
like HOSTNAME (and SECONDS, etc) are used as variables in a script
or whatever, they will act just like normal variables (and unless
this happens when they have been made local, or as a variable-assignment
as a prefix to a command, the special properties they would have had
otherwise are lost for the remainder of the life of the (sub-)shell
in which the variables were set).
Importing a value from the environment counts as setting the
value for this purpose (so if HOSTNAME is set in the environment,
the value there will be the value $HOSTNAME expands to).
The two exceptions to this are LINENO and RANDOM. RANDOM
needs to be able to be set to (re-)set its seed. LINENO needs to
be able to be set (at least in the "local" command) to achieve
the desired functionality. It is unlikely that any (sane) script
is going to want to use those two as normal vars however.
While here, fix a minor bug in popping local vars (fn return) that need
to notify the shell of changes in value (like PATH).
Change sh(1) to reflect this alteration. Also add doc of the
(forgotten) magic var EUSER (which has been there since the others
were added), and add a few more vars (which are documented
in other places in sh(1) - like ENV) into the defined or used
variable list (as well as wherever else they appear).
XXX pullup -8
as traps that issue break/continue/return to cause the loop/function
executing when the trap occurred to break/continue/return, and
generating the correct exit code from the shell including when a
signal is caught, but the trap handler for it exits.
All that from FreeBSD.
Also make
T=$(trap)
work as it is supposed to (also trap -p).
For now this is handled by the same technique as $(jobs) - rather
than clearing the traps in subshells, just mark them invalid, and
then whenever they're invalid, clear them before executing anything
other than the special blessed "trap" command. Eventually we will
handle these using non-subshell command substitution instead (not
creating a subshell environ when the commands in a command-sub alter
nothing in the environment).
intended (and as documented) rather than how it has been behaving
(which was not very rational.) Since it is unlikely that anyone
is using this, the change should be mostly invisible.
While here, a couple of other minor cleanups:
. One call of geteuid() is enough in choose_ps1()
. Fix a typo in a comment
. Improve appearance (whitspace changes) in find_var()
to fix the (unusual) idiom "${1+$@}" (the quotes are part of it).
This seems to have broken about 5 or 6 years ago (somewhere
between -6 and -7), I believe.
Note this is not the same as "$@" and also not the same as ${1+"$@"}
(much more common idioms) which both worked.
Also attempt to deal with "" more correctly, especially when it
appears adjacent to "$@" (or one of the similar constructs.)
This stuff is still all as ugly and hackish (and fragile) as is
possible to imagine, but in an effort to allow some of the weirdness
to eventually go away, the parser output has been made more
regular and all quoted (parts of) words always now start with
CTLQUOTEMARK and end with CTLQUOTEEND regardless of where the
quotes appear.
This allows us to tell the difference between """$@" and "$@"
which was impossible before - yet they are required to generate
different output when there are no args (when "$@" simply vanishes).
Needless to say that change had ramifications all over the place.
To simplify any similar change in the future, there are some new
macros that can generally be used to detect the "noise" data when
processing words, rather than open coding that every time (which
meant that there would *always* be one which missed getting
updated...)
Several other bugs (of my making, and older ones) are also fixed.
The aim is that (aside from anything that is detecting the cases
that were broken before - which were all unlikely uses of sh
syntax) these changes should have no external visible impact.
Sure...
to have them, they should work as documented, not cause core
dumps, reference after free, incorrect replacements, failing
to implement alias after alias, ...
The big comment that ended:
This is a good idea ------- ***NOT***
and the hack it was describing are gone.
Note that most of this was from original CVS version 1.1
code (ie: came from the original import, even before 4.4-Lite
was merged. That is, May 1994. And no-one in 24.5 years
noticed (or at least complained about) all the bugs (or at
least, most of them)).
With these changes, aliases ought to work (if you can call it
that) as they are expected to by POSIX. Now if only we could
get POSIX to delete them (or make them optional)...
Changes partly inspired by similar changes made by FreeBSD,
(as was the previous change to alias.c, forgot ack in commit
log for that one, apologies) but done a little differently,
and perhaps with a slightly better outcome.
to the main handler, rather than wherever the parent shell would go.
nb: not needed for vfork(), after vfork() we never go that path - which
is good or we'd be corrupting the parent's handler.
This allows the child to always exit (when it should) rather than being
caught up doing something else (and while it would eventually exit, the
status would be incorrect in some cases).
One test is:
sh -c 'trap "(! :) && echo BUG || echo nobug" EXIT'
from Martijn Dekker
Fix from FreeBSD (missed earlier).
XXX - 2b part of the 48875 pullup to -8
since this code was first imported (May 1994) (ie: before 4.4-Lite)
There is (much) more coming soon (the big ugly comment is going away).
This one has been separated out, as it can easily cause sh
core dumps, so needs:
XXX pullup-8
(the other changes to aliases probably will not get that.)
what it actually does (makearg would have been an alternative).
While here, notice the one remaining place where it should have been
used, but was left open coded, and consume that one.
NFCI.
for the purposes of any redirects it might have -- ie: as posix
requires, make the redirects appear to have been executed in a subshell
environment, so if one fails, aside from a diagnositc msg, all the
running script sees is a command that failed ($? != 0), rather
that having the shell exit which used to happen (the empty command was
being treated as a special builtin).
Continue to treat the empty command as special for the purposes of
var assigns it might contain (those are not executed in a sub-shell
and persist) - an error there (eg: assigning to a readonly var) will
continue to cause the shell (non-interactive shell) to exit.
This makes the NetBSD shell behave like all other (reasonably modern)
shells - fix method (not the implementation, details differ) taken from
FreeBSD who fixed this back in early 2010. Problem pointed out
in (non-list) mail by Martijn Dekker.
first implemented in response to PR bin/4966 (PR Feb 1998, fix Feb 1999).
The file named should not be truncated.
No other shell truncates the file (<> was added to FreeBSD sh in Oct 2000,
and did not include O_TRUNC) and POSIX certainly does not suggest that
should happen (just that the file is to be created if it does not exist.)
Bug pointed out in off-list e-mail by Martijn Dekker
"command" should not be executed. (The issue affects multi-line
eval strings only - ie: commands after the next \n are not skipped).
Bug noted by Martijn Dekker in off-list e-mail.
Fix from FreeBSD:
src/bin/sh/eval.c: Revision 272983 Sun Oct 12 13:12:06 2014 UTC by jilles
to hide meta-characters in the result when the expansion was
in (double) quotes, and so should not be further processed.
Most of this has been OK for a long while, but \ needs hiding
as well, which complicates things, as \ cannot simply be hidden
in the syntax tables as one of the group of random special characters.
This was fixed earlier for simple variable expansions, but
every variety has its own code path ($var uses different code
than $n which is different than $(...), which is different
again from ~ expansions, and also from what $'...' produces).
This could be fixed by moving them all to a common code path,
but that's harder than it seems. The form in which the data
is made available differs, so one common routine would need
a whole bunch of different "get the next char or indicate end"
methods - probably via passing in an accessor function.
That's all a lot of churn, and would probably slow the shell.
Instead, just make macros for doing the standard tests, and
use those instead of open coding (differently) each time.
This way some of the code paths don't end up forgetting to
handle '\' (which is different than all the others).
This removes one optimisation ... when no escaping is needed
(like just $var (unquoted) where magic chars (think '*') in
the value are intended to remain magic), the code avoided doing
two tests for each char ("do we need escapes" and "is this char
one that needs escaping") by choosing two different syntax
tables (choice made outside the loop) - one of which never
returns the magic "needs escaping" result, and the other does
when appropriate, and then just avoiding the "do we need escapes"
test for each character processed. Then when '\' was fixed,
there needed to be another test for it, as it cannot (for other
reasons) be the same as all the others for which "this char
need escaping" is true. So that added a 2nd test for each char...
Not all the code paths were updated. Hence the bugs...
nb: this is all rarely seen in the wild, so it is no big
surprised that no-one ever noticed.
Now the "use two different syntax tables" is gone (the two
returned the same for '\' which is why '\' needed special
processing) - and in order to avoid two tests for each
char (plus the \ test) we duplicate the loops, one of which
tests each char to see if it needs an escape, the 2nd just
copies them. This should be faster in the "no escapes"
code path (though that is not the point) and perhaps also
in the "escapes needed" path (no indirect reference to
the syntax table - though that would probably be in a
register) but makes the code slightly bigger. For /bin/sh
the text segment (on amd64) has grown by 48 bytes. But
it still uses the same number of 512 byte pages (and hence
also any bigger page size). The resulting file size
(/bin/sh) is identical before and after. So is /rescue/sh
(or /rescue/anything-else).
prompts to exit when they're done, rather than forcing them to
turn into interactive shells and start reading input ...
Completes a part of the previous changes (just 10+ weeks late...)
Should fix the prompt expansion issue reported by Caóc on
current-users.
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.
definitions (just to avoid any temptation to ever use them again).
Update a comment which would make no sense without following the
preceding comment which is being deleted with the macros it describes.
While here, remove another comment that referred to events that have
long past as if they were still to come. Also a grammatical comment
correction - paragraphs start with capital letters...
NFC (even with DEBUG defined).
the ancient DEBUG TRACE() method, to the newer CTRACE() et. al.)
that turns out never really needed committing - the mechanism, and
the code that obsoleted it, were committed together (May 2017).
[It was useful to me while getting to that state...]
NFC. Not even with DEBUG shells.
and use whatever works for the sh running this script. Previously
we were using the (broken, and incorrect) method that worked in
old broken NetBSD sh's (and some others) and not the method that
works with the current (fixed) /bin/sh and other correct shells
(like bash). (For an exotic reason, in the particular use case,
both methods work with ksh93, but it is also generally correct).
This hasn't really mattered, as the difference is only significant
(only causes actual issues - the build fails) when compiling with DEBUG
enabled, which is something that most sane humans would never do, if they
want to retain that sanity.
The problem was detected by Patrick Welche when looking for an
unrelated problem, which was once considered to be a possible sh
problem, but turned out to be something entirely different.
XXX pullup -8
(which has redirects, and so is included in -x output) use the -x/+x
setting that existed when the comoound started, so if the state of
xtrace changes during the command we don't end up with just half of
the -x output (either the intro, or the conclusion, depending on
which way the change happened). [this also happens to avoid a core
dump in the previous code, but that could have been done other ways,
this way actually simplifies things (less code)]
kre