[ipxe-devel] Backslash in chain scripts converted to %5c - escaping issue

Alex Davies alex at davz.net
Wed May 30 16:09:36 UTC 2012

Hi Oliver,

Thanks for your reply. Sadly, the DNS server is Windows and we can't
change it for this particular case (its a menu option for a Windows
installer - even though its pxelinux.0)

The escaping is happening within iPXE, I can see it in the error it
prints on the console as I boot.



On Wed, May 30, 2012 at 12:13 PM, Oliver Rath <rath at mglug.de> wrote:
> Hi Alex
> Am 30.05.2012 12:59, schrieb Oliver Rath:
>> [..]
>> Am 30.05.2012 12:42, schrieb Alex Davies:
>>> Hi All,
>>> If I enter iPXE shell and enter "chain \boot\x86\pxelinux.0",
>>> everything works - it pulls this file via TFTP from next-server.
>>> If I put the same string in a iPXE script and chain that via HTTP,
>>> there is an escaping issue (the slashes are converted to %5C). I have
>>> tried double slashing and adding quotes to no avail (these escape
>>> characters are simply converted too).
>>> Is there another way?
>> You can take i.e. the builtin tftp-server of dnsmasq (if you are using
>> i.e. linux as server). It converts all "\" to "/" in path by default.
>> Addtionally, in dnsmasq 2.61 exists the new --tftp-lowercase option,
>> which converts als chars to lowercase.
> Maybe ive read it not careful enough: It seems you are having a
> windows-based web-server on the other side? So it is really easy: forget
> the "\", you can set the directory in your webserver configuration so
> you dont need it set in ipxe. So say "chain pxelinux.0" and give the
> webserver the information where to find the file. Additionally, the
> directory-structure in URL is alsways done by "/", but every webserver
> can interpret it in ther right way, if you persist on the path.
> The only way you need "\" in the path is a windows-based tftp-server. In
> http-context you never will need it.
> Hth!
> Oliver
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Alex Davies

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