Cannot compile gnutls (ftp problem)

[tobiasBora]

Issue description

Hello,

Nix downloads the gnutls sources using ftp (I guess that it's the only way to bootstrap TLS). However, curl cannot download this ftp files, while wget has no problem at all. Because of that gnutls cannot be installed, and my raspberry installation is quite useless.

Steps to reproduce

Try to install gnutls, or a program that need gnutls on a system that do not have binary for it (like my raspberry). It will fail with a timeout during the downloading of the file ftp://ftp.gnutls.org/gcrypt/gnutls/v3.5/gnutls-3.5.15.tar.xz. The problem seems to be that curl cannot download this ftp file (while wget success... why ?).

$ curl ftp://ftp.gnutls.org/gcrypt/gnutls/v3.5/gnutls-3.5.15.tar.xz -O out.tar.xz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:--  0:00:20 --:--:--     0^C


$ wget ftp://ftp.gnutls.org/gcrypt/gnutls/v3.5/gnutls-3.5.15.tar.xz
--2017-11-28 19:31:21--  ftp://ftp.gnutls.org/gcrypt/gnutls/v3.5/gnutls-3.5.15.tar.xz
           => « gnutls-3.5.15.tar.xz.4 »
Résolution de ftp.gnutls.org (ftp.gnutls.org)… 217.69.76.55
Connexion à ftp.gnutls.org (ftp.gnutls.org)|217.69.76.55|:21… connecté.
Ouverture de session en tant que anonymous… Session établie.
==> SYST ... terminé.    ==> PWD ... terminé.
==> TYPE I ... terminé.  ==> CWD (1) /gcrypt/gnutls/v3.5 ... terminé.
==> SIZE gnutls-3.5.15.tar.xz ... 7238928
==> PASV ... terminé.    ==> RETR gnutls-3.5.15.tar.xz ... terminé.
Taille : 7238928 (6,9M) (non certifiée)

gnutls-3.5.15.tar.xz.4                100%[======================================================================>]   6,90M  2,26MB/s    ds 3,1s    

2017-11-28 19:31:24 (2,26 MB/s) - « gnutls-3.5.15.tar.xz.4 » sauvegardé [7238928]

Technical details

 - system: `"armv6l-linux"`
 - host os: `Linux 4.9.41, NixOS, 18.03.git.66b63d2f5a (Impala)`
 - multi-user?: `no`
 - sandbox: `yes`
 - version: `nix-env (Nix) 1.11.15`
 - channels(root): `"nixos-18.03.git.66b63d2f5a"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs`

[vcunat]

Ah, right, I had already contacted the site administrator. As a fallback, I suppose we can switch to http(s) URLs.

[vcunat]

As a quick workaround, run

nix-prefetch-url http://www.gnupg.org/ftp/gcrypt/gnutls/v3.5/gnutls-3.5.15.tar.xz

and then resume whatever nix operations you wanted.

[tobiasBora]

Thank you very much for the workaround !

And I don't know if it can help, but I tried to debug it, and I found where is the "problem". Here are the commands that curl send (you can try them using telnet ftp.gnutls.org ftp):

USER anonymous
PASS ftp@example.com
PWD
CWD gcrypt
CWD gnutls
CWD v3.5
PASV

And nothing happened after PASV. BUT, if you add a single command PWD before the PASV, it works great:

USER anonymous
PASS ftp@example.com
PWD
CWD gcrypt
CWD gnutls
CWD v3.5
PWD
PASV

[tobiasBora]

Just a question, let us imagine that a website just have ftp, then nix-prefetch-urlwon't work. Can I manually download the file, and add it somehow in the archive files ?

[vcunat]

(1) it does work with ftp:// normally for me; (2) you can use file://.

[tobiasBora]

Ok thanks. I tried to speak with people from curl in IRC:

interesting. I just tried, and it works with --ftp-method nocwd and --ftp-method singlecwd, but not withmulticwd, which IIRC is there because not having that breaks some servers...

Maybe it can help somehow to get a working version, but it may be possible that it break other servers... No idea if it's possible to choose this option only for this specific package.