ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/scripts/download-check-artifact.sh b/scripts/download-check-artifact.sh
new file mode 100755
index 0000000..bc0918b
--- /dev/null
+++ b/scripts/download-check-artifact.sh
@@ -0,0 +1,159 @@
+#!/usr/bin/env bash
+# Script to perform verified file downloads.
+# Exit codes:
+# 0 - File downloaded successfully and verified
+# 1 - Failed to download requested file
+# 2 - Failed to download sha256sums file
+# 3 - Failed to download sha256sums.gpg file
+# 4 - GnuPG is available but fails to verify the signature (missing pubkey, file integrity error, ...)
+# 5 - The checksums do not match
+# 6 - Unable to copy the requested file to its final destination
+# 254 - The script got interrupted by a signal
+# 255 - A suitable download or checksum utility is missing
+
+[ -n "$1" ] || {
+ echo "$0 - Download and verify build artifacts"
+ echo "Usage: $0 <url>" >&2
+ exit 1
+}
+
+finish() {
+ [ -e "/tmp/verify.$$" ] && {
+ echo "Cleaning up."
+ rm -r "/tmp/verify.$$"
+ }
+ exit "$1"
+}
+
+trap "finish 254" INT TERM
+
+destdir="$(pwd)"
+image_url="$1"
+image_file="${image_url##*/}"
+sha256_url="${image_url%/*}/sha256sums"
+gpgsig_url="${image_url%/*}/sha256sums.asc"
+keyserver_url="hkp://keyserver.ubuntu.com"
+
+# Find a suitable download utility
+if which curl >/dev/null; then
+ download() { curl --progress-bar -o "$1" "$2"; }
+elif which wget >/dev/null; then
+ download() { wget -O "$1" "$2"; }
+elif which fetch >/dev/null; then
+ download() { fetch -o "$1" "$2"; }
+else
+ echo "No suitable download utility found, cannot download files!" >&2
+ finish 255
+fi
+
+# Find a suitable checksum utility
+if which sha256sum >/dev/null; then
+ checksum() { sha256sum -c --ignore-missing "sha256sums"; }
+elif which shasum >/dev/null; then
+ checksum() {
+ local sum
+ sum="$(shasum -a 256 "$image_file")";
+ grep -xF "${sum%% *} *$image_file" "sha256sums";
+ }
+else
+ echo "No SHA256 checksum executable installed, cannot verify checksums!" >&2
+ finish 255
+fi
+
+# Check for gpg availability
+if which gpg >/dev/null; then
+ runpgp() { gpg "$@"; }
+else
+ runpgp() {
+ echo "WARNING: No GnuPG installed, cannot verify digital signature!" >&2
+ return 0
+ }
+fi
+
+tmpdir="$(mktemp -d)"
+cd "$tmpdir" || {
+ echo "Failed to create temporary directory!" >&2
+ finish 255
+}
+
+echo ""
+echo "1) Downloading artifact file"
+echo "========================="
+download "$image_file" "$image_url" || {
+ echo "Failed to download image file!" >&2
+ finish 1
+}
+
+echo ""
+echo "2) Downloading checksum file"
+echo "============================"
+download "sha256sums" "$sha256_url" || {
+ echo "Failed to download checksum file!" >&2
+ finish 2
+}
+
+echo ""
+echo "3) Downloading the GPG signature"
+echo "================================"
+download "sha256sums.gpg" "$gpgsig_url" || {
+ echo "Failed to download GPG signature!" >&2
+ finish 3
+}
+
+echo ""
+echo "4) Verifying GPG signature"
+echo "=========================="
+missing_key=$(runpgp --status-fd 1 --with-fingerprint --verify \
+ "sha256sums.gpg" "sha256sums" 2>/dev/null | sed -ne 's!^.* NO_PUBKEY !!p')
+
+if [ -n "$missing_key" ]; then
+ echo "The signature was signed by a public key with the id $missing_key" >&2
+ echo "which is not present on this system." >&2
+ echo "" >&2
+
+ echo "Provide a public keyserver url below or press enter to accept the" >&2
+ echo "default suggestion. Hit Ctrl-C to abort the operation." >&2
+ echo "" >&2
+
+ while true; do
+ printf 'Keyserver to use? [%s] > ' "$keyserver_url"
+ read -r url; case "${url:-$keyserver_url}" in
+ hkp://*)
+ gpg --keyserver "${url:-$keyserver_url}" --recv-keys "$missing_key" || {
+ echo "Failed to download public key." >&2
+ finish 7
+ }
+ break
+ ;;
+ *)
+ echo "Expecting a key server url in the form 'hkp://hostname'." >&2
+ ;;
+ esac
+ done
+fi
+
+runpgp --with-fingerprint --verify "sha256sums.gpg" "sha256sums" || {
+ echo "Failed to verify checksum file with GPG signature!" >&2
+ finish 4
+}
+
+echo ""
+echo "5) Verifying SHA256 checksum"
+echo "============================"
+checksum || {
+ echo "Checksums do not match!" >&2
+ finish 5
+}
+
+cp "$image_file" "$destdir/$image_file" || {
+ echo "Failed to write '$destdir/$image_file'" >&2
+ finish 6
+}
+
+echo ""
+echo "Verification done!"
+echo "=================="
+echo "Downloaded artifact placed in '$destdir/$image_file'."
+echo ""
+
+finish 0