virtual-appliance/scripts/build-kernel

130 lines
3.2 KiB
Python
Executable File

#!/usr/bin/env python
"""Build the latest kernel but only if need be"""
import os
import shutil
import subprocess
EMERGE = os.environ['EMERGE'].split()
USEPKG = os.environ['USEPKG'].split()
def get_latest_available_kernel():
kernel = os.environ['KERNEL']
package_name = 'sys-kernel/{}'.format(kernel)
popen = subprocess.Popen(
['portageq', 'best_visible', '/', package_name],
stdout=subprocess.PIPE,
)
cpv = popen.stdout.read().decode().strip()
return cpv.rpartition('-')[2]
def get_current_kernel():
"""what kernel does /boot/vmlinuz point to"""
vmlinuz = '/boot/vmlinuz'
if not os.path.islink(vmlinuz):
return None
filename = os.path.basename(os.path.realpath(vmlinuz))
assert filename.startswith('vmlinuz')
part_after_vmlinuz = filename[8:]
# may have "-gentoo" or whatever in the name
version = part_after_vmlinuz.rpartition('-')[0]
return version
def install_kernel_package():
kernel = os.environ['KERNEL']
package_name = 'sys-kernel/{}'.format(kernel)
cmd = EMERGE + USEPKG + ['--oneshot', '--noreplace', package_name]
subprocess.check_call(cmd)
def copy_kernel_config():
filename = '/root/kernel.config'
shutil.copy(filename, '/usr/src/linux/.config')
def build_kernel():
makeopts = os.environ.get('MAKEOPTS', '')
subprocess.check_call([
'make', '-C', '/usr/src/linux', 'MAKEOPTS=' + makeopts, 'oldconfig'
])
subprocess.check_call([
'make', '-C', '/usr/src/linux', 'MAKEOPTS=' + makeopts
])
def remove_old_kernels():
kernel_files = ['vmlinuz-', 'System.map-', 'config-']
for filename in os.listdir('/boot'):
for kernel_file in kernel_files:
if filename.startswith(kernel_file):
path = os.path.join('/boot', filename)
os.unlink(path)
if os.path.exists('/boot/vmlinuz'):
os.unlink('/boot/vmlinuz')
shutil.rmtree('/lib/modules', ignore_errors=True)
def install_kernel():
makeopts = os.environ.get('MAKEOPTS', '')
subprocess.check_call([
'make', '-C', '/usr/src/linux', 'MAKEOPTS=' + makeopts, 'install',
'modules_install'
])
# create the symlink. /sbin/installkernel claims this is not used on
# "modern" distributions and doesn't create it (unless it already
# exists). I still do this however.
for filename in os.listdir('/boot'):
if filename.startswith('vmlinuz-'):
os.symlink(filename, '/boot/vmlinuz')
break
else:
raise Exception('Could not find installed kernel')
def uninstall_kernel_package():
subprocess.check_call([
'make', '-C', '/usr/src/linux', 'distclean'
])
subprocess.check_call(EMERGE + USEPKG + ['--depclean', '--with-bdeps=n'])
def backup_kernel_config():
shutil.copy('/usr/src/linux/.config', '/root/kernel.config')
def main():
latest_kernel = get_latest_available_kernel()
current_kernel = get_current_kernel()
if current_kernel == latest_kernel:
return
install_kernel_package()
copy_kernel_config()
build_kernel()
remove_old_kernels()
install_kernel()
backup_kernel_config()
uninstall_kernel_package()
main()