Re: Does struct qstr->name should be terminated ?

[Jerome de Vivie <jerome.devivie@free.fr>]

Bryan Henderson wrote:
>>>I'd think that it's treated as a nomral string in quite a few places, 
> 
> so
> 
>>>it needs to be NUL terminated. (But not searched the sources.)
>>
>>Why not?  It isn't hard to find.
>>
>>fs/dcache.c:703:        str[name->len] = 0;
> 
> 
> That's technically an area where it's treated like a normal string, but 

I thougth that qstr->name was not treated as a normal string and has
been design to speedup d_compare test with strncmp instead of strcmp.
That's why i never bother with the null termination caracter.

> not really relevant to the question (which is "what if I don't 
> nul-terminate the thing"?  Do you have an example handy of a strcmp() or 
> such that would fail if the NUL terminator were not there?

In  yourfs->d_lookup, you can reallocate qstr and pad d_name with random
caracters. After that, unexpected behavior could happen after a mv(1):
the VFS could increment qstr->len. The result is one more caracter for
some entries after a ls(1).