On 09/27/2014 07:47 PM, Chet Ramey wrote: > On 9/27/14, 8:49 PM, Eric Blake wrote: >> On 09/27/2014 05:59 PM, Chet Ramey wrote: >>> On 9/27/14, 4:29 PM, Eric Blake wrote: >>>> On 09/27/2014 12:53 PM, Chet Ramey wrote: > >>> We have an opportunity to close up a potential problem here, at least >>> with respect to function names containing `/'. >> >> As I said in a later mail, I'm now definitely leaning towards your >> desire to exclude '/', and may I also add '=', as two characters that >> will be blacklisted from valid function names both in the shell and >> during import/export, because they are just too risky. I haven't yet >> come up with any reason to blacklist any other non-metacharacter, and >> you already reject any metacharacter that requires quoting. > > I'm just going to include slash for right now, since `=' doesn't cause > any real problems, because you're effectively not able to export it with > the current version.
Bash is not able to export it _as a function_, and likewise, cannot
import it as a function. But the problem is that bash DOES try to
export it, and results in instead POLLUTING the child's namespace.
Consider this behavior in bash 4.3.24:
$ bash -c 'function a=b(){ echo oops;};export -f a=b;export a=hi; bash
-c "echo \$a"'
b=() { echo oops }
or in Fedora bash-4.2.48-2.fc20.x86_64:
$ bash -c 'function a=b(){ echo oops;};export -f a=b;export
BASH_FUNC_a=hi; bash -c "echo \$BASH_FUNC_a"'
b()=() { echo oops }
In both cases, your attempt to export an invalid function name ended up
clobbering a regular variable.
Please reconsider, and prohibit the use of = in function names both for
the 'function' keyword and on imports from the environment.
>
>
>>> Yeah, but what I was talking about was allowing non-identifiers as valid
>>> function names.
>>
>> Where does POSIX forbid the use of a non-identifier as a valid function
>> name?
>
> Yes, it's an application requirement. Regardless, all the versions of bash
> we're talking about here reject non-identifiers.
I'm still trying to find that line in the actual POSIX spec.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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