util/release/build-release: Update script

- Add more help text.
- Remove braces from variables where the variable is isolated.
- Remove --recurse-submodules from clone.  This breaks on old coreboot
- Add some whitespace between blocks.
- Fix all shellcheck warnings.
- Verify tar version and fail if it doesn't support --sort.

Change-Id: I4a49df99532d9a92a4a05bceff16f96a4fc3e205
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/16883
Tested-by: build bot (Jenkins)
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@googlemail.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/util/release/build-release b/util/release/build-release
index 11e7177..20fbfb6 100755
--- a/util/release/build-release
+++ b/util/release/build-release
@@ -3,10 +3,10 @@
 # ${GPG_KEY_ID}: gpg key id (if not don't sign)
 # ${USERNAME}: username (if not default to https)
 # ${COMMIT_ID}: commit id (if not master)
 set -e
@@ -16,32 +16,50 @@
 export LC_ALL LANG TZ
-if [ -z "${VERSION_NAME}" ] || [ "${VERSION_NAME}" = "--help" ]; then
+if [ -z "$VERSION_NAME" ] || [ "$VERSION_NAME" = "--help" ]; then
 	echo "usage: $0 <version> [commit id] [gpg key id] [username]"
-	echo "tags a new coreboot version and creates a tar archive"
+	echo "Tags a new coreboot version and creates a tar archive"
+	echo
+	echo "version:    New version name to tag the tree with"
+	echo "commit id:  check out this commit-id after cloning the coreboot tree"
+	echo "gpg key id: used to tag the version, and generate a gpg signature"
+	echo "username:   clone the tree using ssh://USERNAME - defaults to https://"
 	exit 1
+# Verify that tar supports --sort
+if ! tar --sort=name -cf /dev/null /dev/null 2>/dev/null ; then
+	echo "Error: The installed version of tar does not support --sort"
+	echo "       GNU tar version 1.28 or greater is required.  Exiting."
+	exit 1
 if [ -n "${USERNAME}" ]; then
-	git clone --recurse-submodules ssh://${USERNAME}@review.coreboot.org:29418/coreboot.git coreboot-${VERSION_NAME}
+	git clone "ssh://${USERNAME}@review.coreboot.org:29418/coreboot.git" "coreboot-${VERSION_NAME}"
-	git clone --recurse-submodules https://review.coreboot.org/coreboot.git coreboot-${VERSION_NAME}
+	git clone https://review.coreboot.org/coreboot.git "coreboot-${VERSION_NAME}"
-cd coreboot-${VERSION_NAME}
-if [ -n "${COMMIT_ID}" ]; then
-	git reset --hard ${COMMIT_ID}
+cd "coreboot-${VERSION_NAME}" || exit 1
+if [ -n "$COMMIT_ID" ]; then
+	git reset --hard "$COMMIT_ID"
 git submodule update --init --checkout
-if [ -n "${GPG_KEY_ID}" ]; then
-	git tag -a -s -u ${GPG_KEY_ID} --force ${VERSION_NAME} -m "coreboot version ${VERSION_NAME}"
+if [ -n "$GPG_KEY_ID" ]; then
+	git tag -a -s -u "$GPG_KEY_ID" --force "$VERSION_NAME" -m "coreboot version $VERSION_NAME"
-	git tag -a --force ${VERSION_NAME} -m "coreboot version ${VERSION_NAME}"
+	git tag -a --force "$VERSION_NAME" -m "coreboot version $VERSION_NAME"
-printf "${VERSION_NAME}-$(git log --pretty=%H|head -1)\n" > .coreboot-version
+printf "%s-%s\n" "$VERSION_NAME"  "$(git log --pretty=%H|head -1)" > .coreboot-version
 tstamp=$(git log --pretty=format:%ci -1)
 cd ..
-tar --sort=name --mtime="$tstamp" --owner=coreboot:1000 --group=coreboot:1000 --exclude-vcs --exclude=coreboot-${VERSION_NAME}/3rdparty/blobs -cvf - coreboot-${VERSION_NAME} |xz -9 > coreboot-${VERSION_NAME}.tar.xz
-tar --sort=name --mtime="$tstamp" --owner=coreboot:1000 --group=coreboot:1000 --exclude-vcs -cvf - coreboot-${VERSION_NAME}/3rdparty/blobs |xz -9 > coreboot-blobs-${VERSION_NAME}.tar.xz
+tar --sort=name --mtime="$tstamp" --owner=coreboot:1000 --group=coreboot:1000 --exclude-vcs --exclude="coreboot-${VERSION_NAME}/3rdparty/blobs" -cvf - "coreboot-${VERSION_NAME}" |xz -9 > "coreboot-${VERSION_NAME}.tar.xz"
+tar --sort=name --mtime="$tstamp" --owner=coreboot:1000 --group=coreboot:1000 --exclude-vcs -cvf - "coreboot-${VERSION_NAME}/3rdparty/blobs" |xz -9 > "coreboot-blobs-${VERSION_NAME}.tar.xz"
 if [ -n "${GPG_KEY_ID}" ]; then
-	gpg2 --armor --local-user ${GPG_KEY_ID} --output coreboot-${VERSION_NAME}.tar.xz.sig --detach-sig coreboot-${VERSION_NAME}.tar.xz
-	gpg2 --armor --local-user ${GPG_KEY_ID} --output coreboot-blobs-${VERSION_NAME}.tar.xz.sig --detach-sig coreboot-blobs-${VERSION_NAME}.tar.xz
+	gpg2 --armor --local-user "$GPG_KEY_ID" --output "coreboot-${VERSION_NAME}.tar.xz.sig" --detach-sig "coreboot-${VERSION_NAME}.tar.xz"
+	gpg2 --armor --local-user "$GPG_KEY_ID" --output "coreboot-blobs-${VERSION_NAME}.tar.xz.sig" --detach-sig "coreboot-blobs-${VERSION_NAME}.tar.xz"