From 280a9b13d28b9f581259ba3aa8affb2f049f05a0 Mon Sep 17 00:00:00 2001
From: Toni Uhlig <matzeton@googlemail.com>
Date: Wed, 5 Sep 2018 19:39:12 +0200
Subject: - Makefile should not create symlinks if they exist already - uid/gid
 set to 0/0 in CPIO archive - provide the debian qemu-ifup script (used if
 /etc/qemu-ifup does not exist) - image-reinstall deletes the initramfs but
 leaves all other targets intact

Signed-off-by: Toni Uhlig <matzeton@googlemail.com>
---
 Makefile                   | 17 ++++++++++-------
 scripts/qemu-ifup          | 43 +++++++++++++++++++++++++++++++++++++++++++
 skeleton/root/.placeholder |  0
 3 files changed, 53 insertions(+), 7 deletions(-)
 create mode 100755 scripts/qemu-ifup
 create mode 100644 skeleton/root/.placeholder

diff --git a/Makefile b/Makefile
index c087f39..f88f458 100644
--- a/Makefile
+++ b/Makefile
@@ -109,8 +109,8 @@ $(MUSL_TARGET):
 	cd '$(MUSL_BUILD_DIR)' && (test -r ./config.mak || ./configure --prefix='$(ROOTFS_DIR)/usr')
 	make -C '$(MUSL_BUILD_DIR)' -j$(BUILDJOBS) ARCH='$(ARCH)' V=1 all
 	make -C '$(MUSL_BUILD_DIR)' -j$(BUILDJOBS) ARCH='$(ARCH)' install
-	ln -sr '$(ROOTFS_DIR)/usr/lib' '$(ROOTFS_DIR)/lib' || true
-	ln -sr '$(ROOTFS_DIR)/lib/libc.so' '$(ROOTFS_DIR)/lib/ld-musl-$(ARCH).so.1' || true
+	test -e '$(ROOTFS_DIR)/lib' || ln -sr '$(ROOTFS_DIR)/usr/lib' '$(ROOTFS_DIR)/lib'
+	test -e '$(ROOTFS_DIR)/lib/ld-musl-$(ARCH).so.1' || ln -sr '$(ROOTFS_DIR)/lib/libc.so' '$(ROOTFS_DIR)/lib/ld-musl-$(ARCH).so.1'
 
 $(BUSYBOX_TARGET):
 	cp -v '$(CFG_DIR)/busybox.config' '$(BUSYBOX_BUILD_DIR)/.config'
@@ -128,9 +128,9 @@ build: extract $(LINUX_TARGET) $(MUSL_TARGET) $(BUSYBOX_TARGET)
 
 $(INITRD_TARGET):
 	cp -v '$(SCRIPT_DIR)/init.rootfs' '$(ROOTFS_DIR)/init'
-	cp -rfvTp '$(SKEL_DIR)' '$(ROOTFS_DIR)'
-	chmod 0755 '$(ROOTFS_DIR)/init'
-	cd '$(ROOTFS_DIR)' && find . -print0 | cpio --null -ov --format=newc | gzip -9 > '$(INITRD_TARGET)'
+	chmod 0755                        '$(ROOTFS_DIR)/init'
+	cp -rfvTp '$(SKEL_DIR)'           '$(ROOTFS_DIR)'
+	cd '$(ROOTFS_DIR)' && find . -print0 | cpio --owner 0:0 --null -ov --format=newc | gzip -9 > '$(INITRD_TARGET)'
 
 image: build $(INITRD_TARGET)
 
@@ -146,7 +146,8 @@ image-rebuild: force-remove
 	rm -rf '$(ROOTFS_DIR)'
 	$(DO_BUILD)
 
-image-reinstall: force-remove
+image-reinstall:
+	rm -f '$(INITRD_TARGET)'
 	$(DO_BUILD)
 
 image-repack:
@@ -155,7 +156,8 @@ image-repack:
 
 net:
 	sudo ip tuntap add linux-qemu-test mode tap
-	sudo /etc/qemu-ifup linux-qemu-test
+	test -x /etc/qemu-ifup && sudo /etc/qemu-ifup linux-qemu-test
+	test -x /etc/qemu-ifup || sudo scripts/qemu-ifup linux-qemu-test
 
 qemu: image
 	qemu-system-$(ARCH) -kernel '$(LINUX_BUILD_DIR)/arch/$(ARCH)/boot/bzImage' -initrd '$(INITRD_TARGET)' -enable-kvm -vga qxl -display sdl
@@ -174,6 +176,7 @@ qemu-net: image
 	qemu-system-$(ARCH) -kernel '$(LINUX_BUILD_DIR)/arch/$(ARCH)/boot/bzImage' -initrd '$(INITRD_TARGET)' -enable-kvm -vga qxl -display sdl \
 		-net nic,macaddr=$(NET_HWADDR) -net tap,ifname=linux-qemu-test,br=$(NET_BRIDGE),script=no,downscript=no -append 'net $(if $(NET_IP4),ip4)'
 
+# printf '%*s%-10s - %s\n' '20' 'COMMAND' '' 'HELP'
 define HELP_PREFIX
 	@echo "\t make $1\t- $2"
 endef
diff --git a/scripts/qemu-ifup b/scripts/qemu-ifup
new file mode 100755
index 0000000..20c10de
--- /dev/null
+++ b/scripts/qemu-ifup
@@ -0,0 +1,43 @@
+#! /bin/sh
+# Script to bring a network (tap) device for qemu up.
+# The idea is to add the tap device to the same bridge
+# as we have default routing to.
+
+
+# in order to be able to find brctl
+PATH=$PATH:/sbin:/usr/sbin
+ip=$(which ip)
+
+if [ -n "$ip" ]; then
+   ip link set "$1" up
+else
+   brctl=$(which brctl)
+   if [ ! "$ip" -o ! "$brctl" ]; then
+     echo "W: $0: not doing any bridge processing: neither ip nor brctl utility not found" >&2
+     exit 0
+   fi
+   ifconfig "$1" 0.0.0.0 up
+fi
+
+switch=$(ip route ls | \
+    awk '/^default / {
+          for(i=0;i<NF;i++) { if ($i == "dev") { print $(i+1); next; } }
+         }'
+        )
+
+# only add the interface to default-route bridge if we
+# have such interface (with default route) and if that
+# interface is actually a bridge.
+# It is possible to have several default routes too
+for br in $switch; do
+    if [ -d /sys/class/net/$br/bridge/. ]; then
+        if [ -n "$ip" ]; then
+          ip link set "$1" master "$br"
+        else
+          brctl addif $br "$1"
+        fi
+        exit	# exit with status of the previous command
+    fi
+done
+
+echo "W: $0: no bridge for guest interface found" >&2
diff --git a/skeleton/root/.placeholder b/skeleton/root/.placeholder
new file mode 100644
index 0000000..e69de29
-- 
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