2e113f6b9d
Two instances of the fetch-params.sh script running at once will result in corruption of the proving key and an error when the hashes are computed. This implements a lock to stop such a scenario from occurring. We also terminate and don't create the symlinks if the downloaded parameters fail the checksum command.
122 lines
3.5 KiB
Bash
Executable File
122 lines
3.5 KiB
Bash
Executable File
#!/bin/bash
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set -eu
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PARAMS_DIR="$HOME/.zcash-params"
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REGTEST_PKEY_NAME='z9-proving.key'
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REGTEST_VKEY_NAME='z9-verifying.key'
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REGTEST_PKEY_URL="https://z.cash/downloads/$REGTEST_PKEY_NAME"
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REGTEST_VKEY_URL="https://z.cash/downloads/$REGTEST_VKEY_NAME"
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REGTEST_DIR="$PARAMS_DIR/regtest"
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# This should have the same params as regtest. We use symlinks for now.
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TESTNET3_DIR="$PARAMS_DIR/testnet3"
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function fetch_params {
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local url="$1"
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local output="$2"
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local dlname="${output}.dl"
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if ! [ -f "$output" ]
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then
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echo "Retrieving: $url"
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# Note: --no-check-certificate should be ok, since we rely on
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# sha256 for integrity, and there's no confidentiality requirement.
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# Our website uses letsencrypt certificates which are not supported
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# by some wget installations, so we expect some cert failures.
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wget \
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--progress=dot:giga \
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--no-check-certificate \
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--output-document="$dlname" \
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--continue \
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"$url"
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# Only after successful download do we update the parameter load path:
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mv -v "$dlname" "$output"
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fi
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}
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# Use flock to prevent parallel execution.
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function lock() {
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local lockfile=/tmp/fetch_params.lock
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# create lock file
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eval "exec 200>/$lockfile"
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# acquire the lock
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flock -n 200 \
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&& return 0 \
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|| return 1
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}
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function exit_locked_error {
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echo "Only one instance of fetch-params.sh can be run at a time." >&2
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exit 1
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}
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function main() {
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lock fetch-params.sh \
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|| exit_locked_error
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cat <<EOF
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Zcash - fetch-params.sh
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EOF
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# Now create PARAMS_DIR and insert a README if necessary:
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if ! [ -d "$PARAMS_DIR" ]
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then
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mkdir -p "$PARAMS_DIR"
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README_PATH="$PARAMS_DIR/README"
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cat >> "$README_PATH" <<EOF
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This directory stores common Zcash zkSNARK parameters. Note that it is
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distinct from the daemon's -datadir argument because the parameters are
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large and may be shared across multiple distinct -datadir's such as when
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setting up test networks.
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EOF
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# This may be the first time the user's run this script, so give
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# them some info, especially about bandwidth usage:
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cat <<EOF
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This script will fetch the Zcash zkSNARK parameters and verify their
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integrity with sha256sum.
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The parameters are currently just under 911MB in size, so plan accordingly
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for your bandwidth constraints. If the files are already present and
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have the correct sha256sum, no networking is used.
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Creating params directory. For details about this directory, see:
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$README_PATH
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EOF
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fi
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mkdir -p "$REGTEST_DIR"
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fetch_params "$REGTEST_PKEY_URL" "$REGTEST_DIR/$REGTEST_PKEY_NAME"
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fetch_params "$REGTEST_VKEY_URL" "$REGTEST_DIR/$REGTEST_VKEY_NAME"
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cd "$PARAMS_DIR"
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# Now verify their hashes:
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echo 'Verifying parameter file integrity via sha256sum...'
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shasum -a 256 --check <<EOF
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226913bbdc48b70834f8e044d194ddb61c8e15329f67cdc6014f4e5ac11a82ab regtest/$REGTEST_PKEY_NAME
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4c151c562fce2cdee55ac0a0f8bd9454eb69e6a0db9a8443b58b770ec29b37f5 regtest/$REGTEST_VKEY_NAME
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EOF
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# Check the exit code of the shasum command:
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CHECKSUM_RESULT=$?
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if [ $CHECKSUM_RESULT -eq 0 ]; then
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echo 'Updating testnet3 symlinks to regtest parameters.'
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mkdir -p "$TESTNET3_DIR"
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ln -sf "../regtest/$REGTEST_PKEY_NAME" "$TESTNET3_DIR/$REGTEST_PKEY_NAME"
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ln -sf "../regtest/$REGTEST_VKEY_NAME" "$TESTNET3_DIR/$REGTEST_VKEY_NAME"
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else
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exit 1
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fi
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}
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main
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exit 0
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