[Buildroot] [PATCH v2] download: fix file:// BR2_PRIMARY_SITE (download cache)

[Yann E. MORIN <yann.morin.1998@free.fr>]

Hollis, All,

On 2018-07-18 20:42 -0700, Hollis Blanchard spake thusly:
> As far as I can tell, wget is the only downloader currently usable with
> BR2_PRIMARY_SITE, and that doesn't work at all for file:// URLs. The symptoms
> are these:

Why do you need to have a primary that points to local files? Isn't it
sufficient to export BR2_DL_DIR and opint it to your local cache
instead?

Regards,
Yann E. MORIN.

> 	support/download/dl-wrapper -c '2.4.47' -d '/PATH/build/sw/source/attr' -D '/PATH/build/sw/source' -f 'attr-2.4.47.src.tar.gz' -H 'package/attr//attr.hash' -n 'attr-2.4.47' -N 'attr' -o '/PATH/build/sw/source/attr/attr-2.4.47.src.tar.gz'  -u file\|urlencode+file:///NFS/buildroot_dl_cache/attr -u file\|urlencode+file:///NFS/buildroot_dl_cache -u http+http://download.savannah.gnu.org/releases/attr -u http\|urlencode+http://sources.buildroot.net/attr -u http\|urlencode+http://sources.buildroot.net  -- 
> 	file:///NFS/buildroot_dl_cache/attr/attr-2.4.47.src.tar.gz: Unsupported scheme `file'.
> 	ERROR: attr-2.4.47.src.tar.gz has wrong sha256 hash:
> 	ERROR: expected: 25772f653ac5b2e3ceeb89df50e4688891e21f723c460636548971652af0a859
> 	ERROR: got     : e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
> 	ERROR: Incomplete download, or man-in-the-middle (MITM) attack
> 
> In the case of custom Linux kernel versions, this is fatal, because there isn't
> necessarily a hash file to indicate that wget's empty tarball is wrong.
> 
> This seems to have been broken by commit c8ef0c03b0b, because:
> 1. BR2_PRIMARY_SITE always appends "urlencode" (package/pkg-download.mk)
> 2. Anything with the "|urlencode" suffix in $uri will end up using wget due to
>    the backend case wildcarding.
> 3. The wget backend rejects file:/// URLs ("unsupported scheme"), and we end up
>    with an empty .tar.gz file in the downloads directory.
> 
> Fix that by shell-extracting the backend name from the left of "|". I'm not
> positive if all URLs will have a "|", so this code only looks for a "|" left of
> the "+".
> 
> Signed-off-by: Hollis Blanchard <hollis_blanchard@mentor.com>
> ---
>  support/download/dl-wrapper | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/support/download/dl-wrapper b/support/download/dl-wrapper
> index 8d6365e08d..610dcba5a5 100755
> --- a/support/download/dl-wrapper
> +++ b/support/download/dl-wrapper
> @@ -88,7 +88,8 @@ main() {
>      download_and_check=0
>      rc=1
>      for uri in "${uris[@]}"; do
> -        backend=${uri%%+*}
> +        backend_urlencode=${uri%%+*}
> +        backend=${backend_urlencode%|*}
>          case "${backend}" in
>              git|svn|cvs|bzr|file|scp|hg) ;;
>              *) backend="wget" ;;
> -- 
> 2.13.0
> 

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