runqemu: Add network bridge support

Qemu supports attaching the virtual machine to an existing network
bridge interface via the qemu-bridge-helper program (as long as the
system is correctly configured to give the user permissions). Add
support for runqemu to do this also via the "bridge=<INTERFACE>"
argument. Note that for this to work correctly, the host
qemu-bridge-helper must be used, not the one that might have been built
by qemu-native. In order for qemu to correctly find this program, a
qemu-oe-bridge-helper program has been added to qemu-helper-native, and
runqemu will use this helper as the bridge helper. The helper will look
for the host qemu-bridge-helper first by looking in the
QEMU_BRIDGE_HELPER environment variable, then by search common paths
where the helper is installed.

(From OE-Core rev: 9e7b38c61c6b84b7f137c733ac5da9414025693d)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/meta/recipes-devtools/qemu/qemu-helper/qemu-oe-bridge-helper b/meta/recipes-devtools/qemu/qemu-helper/qemu-oe-bridge-helper
new file mode 100755
index 0000000000..f057d4eef0
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu-helper/qemu-oe-bridge-helper
@@ -0,0 +1,25 @@
+#! /bin/sh
+# Copyright 2020 Garmin Ltd. or its subsidiaries
+#
+# SPDX-License-Identifier: GPL-2.0
+#
+# Attempts to find and exec the host qemu-bridge-helper program
+
+# If the QEMU_BRIDGE_HELPER variable is set by the user, exec it.
+if [ -n "$QEMU_BRIDGE_HELPER" ]; then
+    exec "$QEMU_BRIDGE_HELPER" "$@"
+fi
+
+# Search common paths for the helper program
+BN="qemu-bridge-helper"
+PATHS="/usr/libexec/ /usr/lib/qemu/"
+
+for p in $PATHS; do
+    if [ -e "$p/$BN" ]; then
+        exec "$p/$BN" "$@"
+    fi
+done
+
+echo "$BN not found!" > /dev/stderr
+exit 1
+