nix-super/scripts/nix-prefetch-url.in
2004-10-20 14:40:54 +00:00

52 lines
1.3 KiB
Text

#! @shell@ -e
url=$1
if test -z "$url"; then
echo "syntax: nix-prefetch-url URL" >&2
exit 1
fi
# !!! race
tmpPath1=@storedir@/nix-prefetch-url-$$
# Test whether we have write permission in the store. If not, fetch
# to /tmp and don't copy to the store. This is a hack to make this
# script at least work somewhat in setuid installations.
if ! touch $tmpPath1 2> /dev/null; then
echo "(cannot write to the store, result won't be cached)" >&2
dummyMode=1
tmpPath1=/tmp/nix-prefetch-url-$$ # !!! security?
fi
# Perform the checkout.
@curl@ --fail --location --max-redirs 20 "$url" > $tmpPath1
# Compute the hash.
hash=$(@bindir@/nix-hash --flat $tmpPath1)
echo "hash is $hash" >&2
# Rename it so that the fetchurl builder can find it.
if test "$dummyMode" != 1; then
tmpPath2=@storedir@/nix-prefetch-url-$hash
test -e $tmpPath2 || mv $tmpPath1 $tmpPath2 # !!! race
fi
# Create a Nix expression that does a fetchurl.
storeExpr=$( \
echo "(import @datadir@/nix/corepkgs/fetchurl) \
{url = $url; md5 = \"$hash\"; system = \"@system@\";}" \
| @bindir@/nix-instantiate -)
# Realise it.
finalPath=$(@bindir@/nix-store -qnB --force-realise $storeExpr)
echo "path is $finalPath" >&2
rm -rf $tmpPath1 $tmpPath2 || true
echo $hash
if test -n "$PRINT_PATH"; then
echo $finalPath
fi