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

[Hollis Blanchard]

Sorry, I need to respin this.

Hollis Blanchard
Mentor Graphics Emulation Division

On 07/18/2018 08:34 PM, Hollis Blanchard wrote:
> 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:
>
> 	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
>
> After a few failed attempts at using the download cache, dl-support downloads
> from the upstream source instead.
>
> 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 $uri will end up using wget due to
>     the backend case wildcarding.
> 3. The wget backend rejects file:/// URLs ("unsupported scheme"), and we end up
>     with an empty .tar.gz file in the downloads directory.
>
> Fix that by shell-extracting the backend name from the left of "|". I'm not
> positive if all URLs will have a "|", so this code only looks for a "|" left of
> the "+".
>
> Signed-off-by: Hollis Blanchard <hollis_blanchard at mentor.com>
> ---
>   support/download/dl-wrapper | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/support/download/dl-wrapper b/support/download/dl-wrapper
> index 8d6365e08d..610dcba5a5 100755
> --- a/support/download/dl-wrapper
> +++ b/support/download/dl-wrapper
> @@ -88,7 +88,8 @@ main() {
>       download_and_check=0
>       rc=1
>       for uri in "${uris[@]}"; do
> -        backend=${uri%+*}
> +        backend_urlencode=${uri%+*}
> +        backend=${backend_urlencode%|*}
>           case "${backend}" in
>               git|svn|cvs|bzr|file|scp|hg) ;;
>               *) backend="wget" ;;