Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 104 insertions, 0 deletions

diff --git a/scripts/git-submodule.sh b/scripts/git-submodule.sh
new file mode 100755
index 000000000..e225d3a96
--- /dev/null
+++ b/scripts/git-submodule.sh
@@ -0,0 +1,104 @@
+#!/bin/sh
+#
+# This code is licensed under the GPL version 2 or later.  See
+# the COPYING file in the top-level directory.
+
+substat=".git-submodule-status"
+
+command=$1
+shift
+maybe_modules="$@"
+
+# if --with-git-submodules=ignore, do nothing
+test "$command" = "ignore" && exit 0
+
+test -z "$GIT" && GIT=git
+
+cd "$(dirname "$0")/.."
+
+update_error() {
+    echo "$0: $*"
+    echo
+    echo "Unable to automatically checkout GIT submodules '$modules'."
+    echo "If you require use of an alternative GIT binary (for example to"
+    echo "enable use of a transparent proxy), then please specify it by"
+    echo "running configure by with the '--with-git' argument. e.g."
+    echo
+    echo " $ ./configure --with-git='tsocks git'"
+    echo
+    echo "Alternatively you may disable automatic GIT submodule checkout"
+    echo "with:"
+    echo
+    echo " $ ./configure --with-git-submodules=validate"
+    echo
+    echo "and then manually update submodules prior to running make, with:"
+    echo
+    echo " $ scripts/git-submodule.sh update $modules"
+    echo
+    exit 1
+}
+
+validate_error() {
+    if test "$1" = "validate"; then
+        echo "GIT submodules checkout is out of date, and submodules"
+        echo "configured for validate only. Please run"
+        echo "  scripts/git-submodule.sh update $maybe_modules"
+        echo "from the source directory or call configure with"
+        echo "  --with-git-submodules=update"
+        echo "To disable GIT submodules validation, use"
+        echo "  --with-git-submodules=ignore"
+    fi
+    exit 1
+}
+
+modules=""
+for m in $maybe_modules
+do
+    $GIT submodule status $m 1> /dev/null 2>&1
+    if test $? = 0
+    then
+        modules="$modules $m"
+    else
+        echo "warn: ignoring non-existent submodule $m"
+    fi
+done
+
+if test -n "$maybe_modules" && ! test -e ".git"
+then
+    echo "$0: unexpectedly called with submodules but no git checkout exists"
+    exit 1
+fi
+
+case "$command" in
+status|validate)
+    if test -z "$maybe_modules"
+    then
+         test -s ${substat} && validate_error "$command" || exit 0
+    fi
+
+    test -f "$substat" || validate_error "$command"
+    for module in $modules; do
+        CURSTATUS=$($GIT submodule status $module)
+        OLDSTATUS=$(cat $substat | grep $module)
+        if test "$CURSTATUS" != "$OLDSTATUS"; then
+            validate_error "$command"
+        fi
+    done
+    exit 0
+    ;;
+update)
+    if test -z "$maybe_modules"
+    then
+        test -e $substat || touch $substat
+        exit 0
+    fi
+
+    $GIT submodule update --init $modules 1>/dev/null
+    test $? -ne 0 && update_error "failed to update modules"
+
+    $GIT submodule status $modules > "${substat}"
+    test $? -ne 0 && update_error "failed to save git submodule status" >&2
+    ;;
+esac
+
+exit 0