On 2010-10-15, Chris Torek <nos...@torek.net> wrote:
>>> On 2010-10-15, Grant Edwards <inva...@invalid.invalid> wrote:
>>>> How do you create a [Unix] file with a name that contains a NULL byte?
>
>>On 2010-10-15, Seebs <usenet-nos...@seebs.net> wrote:
>>> So far as I know, in canonical Unix, you don't -- the syscalls all work
>>> with something like C strings under the hood, meaning that no matter what
>>> path name you send, the first null byte actually terminates it.
>
> In article <i9a84m$rp...@reader1.panix.com> Grant Edwards
> <inva...@invalid.invalid> wrote:
>
>>Yes, all of the Unix syscalls use NULL-terminated path parameters (AKA
>>"C strings"). What I don't know is whether the underlying filesystem
>>code also uses NULL-terminated strings for filenames or if they have
>>explicit lengths. If the latter, there might be some way to bypass
>>the normal Unix syscalls and actually create a file with a NULL in its
>>name -- a file that then couldn't be accessed via the normal Unix
>>system calls. My _guess_ is that the underlying filesystem code in
>>most all Unices also uses NULL-terminated strings, but I haven't
>>looked yet.
>
> Multiple common on-disk formats (BSD's UFS variants and Linux's EXTs,
> for instance) use counted strings, so it is possible -- via disk
> corruption or similar -- to get "impossible" file names (those
> containing either an embedded NUL or an embedded '/').
That appeared it might be the case after a quick browsing of some of
the fs source code, but I wasn't sure.
> More notoriously, earlier versions of NFS could create files with
> embedded slashes when serving non-Unix clients. These were easily
> removed with the same non-Unix client, but not on the server! :-)
>
> None of this has anything to do with the original problem,
No, we left that track miles back...
--
Grant Edwards grant.b.edwards Yow! I'm having an
at emotional outburst!!
gmail.com
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