libfetch ftp patch for less latency

[Dag-Erling Smørgrav]

Nate Lawson <nate at root.org> writes:
> To speed up pkg_add and other ftp command channel performance over slow
> links, change this:
>
>>>> PWD
> <<< 257 "/"
>>>> CWD pub
> <<< 250 Directory successfully changed.
>>>> CWD FreeBSD
> <<< 250 Directory successfully changed.
>>>> CWD ports
> <<< 250 Directory successfully changed.
>>>> CWD amd64
> <<< 250 Directory successfully changed.
>>>> CWD packages-6-stable
> <<< 250 Directory successfully changed.
>>>> CWD Latest
> <<< 250 Directory successfully changed.
>>>> MODE S
>
> Into this:
>
>>>> PWD
> <<< 257 "/"
>>>> CWD pub/FreeBSD/ports/amd64/packages-6-stable/Latest
> <<< 250 Directory successfully changed.

No.  This is a violation of the FTP protocol.

> All ftp servers I've ever seen support a full path when changing down
> dirs. This might be a DOS ftp server thing however.  In any case, if
> there is an error to the all-in-one CWD, the code reverts back to legacy
> behavior of multiple CWDs.

When the all-in-one CWD fails, you're SOL.  You have no idea what
state the server is in, and you have to start over.

DES
-- 
Dag-Erling Smørgrav - des at des.no