server/deb_kernel.py

#!/usr/bin/python
#
# Copyright 2007 Google Inc. Released under the GPL v2

"""This module defines the Kernel class

	Kernel: an os kernel
"""

__author__ = """mbligh@google.com (Martin J. Bligh),
poirier@google.com (Benjamin Poirier),
stutsman@google.com (Ryan Stutsman)"""


import os
import os.path
import time
import urllib

import kernel
import errors
import utils


class DEBKernel(kernel.Kernel):
	"""This class represents a .deb pre-built kernel.

	It is used to obtain a built kernel and install it on a Host.

	Implementation details:
	This is a leaf class in an abstract class hierarchy, it must
	implement the unimplemented methods in parent classes.
	"""
	def __init__(self):
		super(DEBKernel, self).__init__()


	def install(self, host, **kwargs):
		"""Install a kernel on the remote host.
		
		This will also invoke the guest's bootloader to set this
		kernel as the default kernel.
		
		Args:
			host: the host on which to install the kernel
			[kwargs]: remaining keyword arguments will be passed 
				to Bootloader.add_kernel()
		
		Raises:
			AutoservError: no package has yet been obtained. Call
				DEBKernel.get() with a .deb package.
		"""
		if self.source_material is None:
			raise AutoservError("A kernel must first be \
			specified via get()")
		
		remote_tmpdir = host.get_tmp_dir()
		basename = os.path.basename(self.source_material)
		remote_filename = os.path.join(remote_tmpdir, basename)
		host.send_file(self.source_material, remote_filename)
		host.run('dpkg -i "%s"' % (utils.sh_escape(remote_filename),))
		host.run('mkinitramfs -o "%s" "%s"' % (
			utils.sh_escape(self.get_initrd_name()), 
			utils.sh_escape(self.get_version()),))
		
		host.bootloader.add_kernel(self.get_image_name(), 
			initrd=self.get_initrd_name(), **kwargs)
	
	def get_version(self):
		"""Get the version of the kernel to be installed.
		
		Returns:
			The version string, as would be returned 
			by 'make kernelrelease'.
		
		Raises:
			AutoservError: no package has yet been obtained. Call
				DEBKernel.get() with a .deb package.
		"""
		if self.source_material is None:
			raise AutoservError("A kernel must first be \
			specified via get()")
		
		retval= utils.run('dpkg-deb -f "%s" version' % 
			utils.sh_escape(self.source_material),)
		return retval.stdout.strip()
	
	def get_image_name(self):
		"""Get the name of the kernel image to be installed.
		
		Returns:
			The full path to the kernel image file as it will be 
			installed on the host.
		
		Raises:
			AutoservError: no package has yet been obtained. Call
				DEBKernel.get() with a .deb package.
		"""
		return "/boot/vmlinuz-%s" % (self.get_version(),)
	
	def get_initrd_name(self):
		"""Get the name of the initrd file to be installed.
		
		Returns:
			The full path to the initrd file as it will be 
			installed on the host. If the package includes no 
			initrd file, None is returned
		
		Raises:
			AutoservError: no package has yet been obtained. Call
				DEBKernel.get() with a .deb package.
		"""
		if self.source_material is None:
			raise AutoservError("A kernel must first be \
			specified via get()")
		
		return "/boot/initrd.img-%s" % (self.get_version(),)