Xen devel - Apr 2008 - Re: Use PATH_MAX for pathname char arrays.

Hello,

Using PATH_MAX is not a good idea: POSIX says that that definition
is facultative, in case the system does not impose any limit on path
length.  Some systems may also set PATH_MAX to a quite high value, and
we would hence consume a lot of stack.

Samuel

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

If there are better alternatives I''d be happy to use them instead. But
we
already use PATH_MAX elsewhere in the tools, so this might be a
wider-ranging cleanup than you think. The original impetus for this change
was due to bugchecks applied in some cases by glibc''s realpath()
implementation. But actually is realpath() deprecated anyway?

 -- Keir

On 4/4/08 15:17, "Samuel Thibault"
<samuel.thibault@eu.citrix.com> wrote:
> Hello,
> 
> Using PATH_MAX is not a good idea: POSIX says that that definition
> is facultative, in case the system does not impose any limit on path
> length.  Some systems may also set PATH_MAX to a quite high value, and
> we would hence consume a lot of stack.
> 
> Samuel
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

Keir Fraser, le Fri 04 Apr 2008 15:30:52 +0100, a écrit
:
> If there are better alternatives I''d be happy to use them instead.
But we
> already use PATH_MAX elsewhere in the tools, so this might be a
> wider-ranging cleanup than you think.
That''s possible indeed, I''m just making sure we try to avoid
adding
others :)
> The original impetus for this change was due to bugchecks applied in
> some cases by glibc''s realpath() implementation.
> But actually is realpath() deprecated anyway?
Ah, right, realpath has a bad semantic indeed.  The intent of SUS is to
have it allocate the string if NULL is given, but that''s not
necessarily
implemented yet.  In the wild, I only know GNU/Hurd which doesn''t have
any PATH_MAX limit, and it happens that that one has the allocation
behavior.

Samuel

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel