Fix installation of vbox guest additions.

Credits for this idea go to @myhro who suggested emulating uname.

I cleaned his changes up somewhat and moved the script into a
separate file to make things easier to look at.

I did a test build of wheezy with my changes and the modules were
installed correctly.

root@localhost:/home/vagrant# dkms status
vboxguest, 4.3.20, 3.2.0-4-amd64, x86_64: installed

root@localhost:/home/vagrant# lsmod | egrep ^vbox
vboxsf                 33359  0
vboxvideo              12437  0
vboxguest             162115  1 vboxsf

bootstrapvz/providers/virtualbox/assets/install_guest_additions.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+function uname {
+  if [[ $1 == '-r' ]]; then
+    echo "KERNEL_VERSION"
+    return 0
+  elif [[ $1 == '-m' ]]; then
+    echo "KERNEL_ARCH"
+    return 0
+  else
+    $(which uname) $@
+  fi
+}
+export -f uname
+
+INSTALL_SCRIPT --nox11

bootstrapvz/providers/virtualbox/tasks/guest_additions.py

@@ -2,6 +2,9 @@ from bootstrapvz.base import Task
 from bootstrapvz.common import phases
 from bootstrapvz.common.tasks.packages import InstallPackages
 from bootstrapvz.common.exceptions import TaskError
+import os
+
+assets = os.path.normpath(os.path.join(os.path.dirname(__file__), '../assets'))
 
 
 class CheckGuestAdditionsPath(Task):
@@ -10,7 +13,6 @@ class CheckGuestAdditionsPath(Task):
 
 	@classmethod
 	def run(cls, info):
-		import os.path
 		guest_additions_path = info.manifest.provider['guest_additions']
 		if not os.path.exists(guest_additions_path):
 			msg = 'The file {file} does not exist.'.format(file=guest_additions_path)
@@ -27,12 +29,19 @@ class AddGuestAdditionsPackages(Task):
 		info.packages.add('bzip2')
 		info.packages.add('build-essential')
 		info.packages.add('dkms')
+
 		kernel_headers_pkg = 'linux-headers-'
 		if info.manifest.system['architecture'] == 'i386':
+			arch = 'i686'
 			kernel_headers_pkg += '686-pae'
 		else:
+			arch = 'x86_64'
 			kernel_headers_pkg += 'amd64'
 		info.packages.add(kernel_headers_pkg)
+		info.kernel = {
+			'arch': arch,
+			'headers_pkg': kernel_headers_pkg,
+		}
 
 
 class InstallGuestAdditions(Task):
@@ -42,19 +51,35 @@ class InstallGuestAdditions(Task):
 
 	@classmethod
 	def run(cls, info):
-		import os
+		from bootstrapvz.common.tools import log_call, log_check_call
+		for line in log_check_call(['chroot', info.root, 'apt-cache', 'show', info.kernel['headers_pkg']]):
+			key, value = line.split(':')
+			if key.strip() == 'Depends':
+				kernel_version = value.strip().split('linux-headers-')[-1]
+				break
+
 		guest_additions_path = info.manifest.provider['guest_additions']
 		mount_dir = 'mnt/guest_additions'
 		mount_path = os.path.join(info.root, mount_dir)
 		os.mkdir(mount_path)
 		root = info.volume.partition_map.root
 		root.add_mount(guest_additions_path, mount_path, ['-o', 'loop'])
-
                 install_script = os.path.join('/', mount_dir, 'VBoxLinuxAdditions.run')
+                install_wrapper_name = 'install_guest_additions.sh'
+                install_wrapper = open(os.path.join(assets, install_wrapper_name)) \
+                        .read() \
+                        .replace("KERNEL_VERSION", kernel_version) \
+                        .replace("KERNEL_ARCH", info.kernel['arch']) \
+                        .replace("INSTALL_SCRIPT", install_script)
+		install_wrapper_path = os.path.join(info.root, install_wrapper_name)
+		with open(install_wrapper_path, 'w') as f:
+			f.write(install_wrapper + '\n')
+
 		# Don't check the return code of the scripts here, because 1 not necessarily means they have failed
-		from bootstrapvz.common.tools import log_call
+		log_call(['chroot', info.root, 'bash', '/' + install_wrapper_name])
-		log_call(['chroot', info.root, install_script, '--nox11'])
+
 		# VBoxService process could be running, as it is not affected by DisableDaemonAutostart
 		log_call(['chroot', info.root, 'service', 'vboxadd-service', 'stop'])
 		root.remove_mount(mount_path)
 		os.rmdir(mount_path)
+		os.remove(install_wrapper_path)