[sonic_installer] Refactor sonic_installer code (sonic-net#953)

Add a new Bootloader abstraction.
This makes it easier to add bootloader specific behavior while keeping
the main logic identical.
It is also a step that will ease the introduction of secureboot which
relies on bootloader specific behaviors.

Shuffle code around to get rid of the hacky if/else all over the place.
There are now 3 bootloader classes
 - AbootBootloader
 - GrubBootloader
 - UbootBootloader

There was almost no logic change in any of the implementations.
Only the AbootBootloader saw some small improvements.
More will follow in subsequent changes.

setup.py

@@ -49,6 +49,7 @@
  'pddf_ledutil',
  'show',
  'sonic_installer',
+ 'sonic_installer.bootloader',
  'sonic-utilities-tests',
  'undebug',
  'utilities_common',

sonic_installer/bootloader/__init__.py

@@ -0,0 +1,16 @@
+
+from .aboot import AbootBootloader
+from .grub import GrubBootloader
+from .uboot import UbootBootloader
+
+BOOTLOADERS = [
+ AbootBootloader,
+ GrubBootloader,
+ UbootBootloader,
+]
+
+def get_bootloader():
+ for bootloaderCls in BOOTLOADERS:
+ if bootloaderCls.detect():
+ return bootloaderCls()
+ raise RuntimeError('Bootloader could not be detected')

sonic_installer/bootloader/aboot.py

@@ -0,0 +1,125 @@
+"""
+Bootloader implementation for Aboot used on Arista devices
+"""
+
+import collections
+import os
+import re
+import subprocess
+
+import click
+
+from ..common import (
+ HOST_PATH,
+ IMAGE_DIR_PREFIX,
+ IMAGE_PREFIX,
+ run_command,
+)
+from .bootloader import Bootloader
+
+_secureboot = None
+def isSecureboot():
+ global _secureboot
+ if _secureboot is None:
+ with open('/proc/cmdline') as f:
+ m = re.search(r"secure_boot_enable=[y1]", f.read())
+ _secureboot = bool(m)
+ return _secureboot
+
+class AbootBootloader(Bootloader):
+
+ NAME = 'aboot'
+ BOOT_CONFIG_PATH = os.path.join(HOST_PATH, 'boot-config')
+ DEFAULT_IMAGE_PATH = '/tmp/sonic_image.swi'
+
+ def _boot_config_read(self, path=BOOT_CONFIG_PATH):
+ config = collections.OrderedDict()
+ with open(path) as f:
+ for line in f.readlines():
+ line = line.strip()
+ if not line or line.startswith('#') or '=' not in line:
+ continue
+ key, value = line.split('=', 1)
+ config[key] = value
+ return config
+
+ def _boot_config_write(self, config, path=BOOT_CONFIG_PATH):
+ with open(path, 'w') as f:
+ f.write(''.join('%s=%s\n' % (k, v) for k, v in config.items()))
+
+ def _boot_config_set(self, **kwargs):
+ path = kwargs.pop('path', self.BOOT_CONFIG_PATH)
+ config = self._boot_config_read(path=path)
+ for key, value in kwargs.items():
+ config[key] = value
+ self._boot_config_write(config, path=path)
+
+ def _swi_image_path(self, image):
+ image_dir = image.replace(IMAGE_PREFIX, IMAGE_DIR_PREFIX)
+ if isSecureboot():
+ return 'flash:%s/sonic.swi' % image_dir
+ return 'flash:%s/.sonic-boot.swi' % image_dir
+
+ def get_current_image(self):
+ with open('/proc/cmdline') as f:
+ current = re.search(r"loop=/*(\S+)/", f.read()).group(1)
+ return current.replace(IMAGE_DIR_PREFIX, IMAGE_PREFIX)
+
+ def get_installed_images(self):
+ images = []
+ for filename in os.listdir(HOST_PATH):
+ if filename.startswith(IMAGE_DIR_PREFIX):
+ images.append(filename.replace(IMAGE_DIR_PREFIX, IMAGE_PREFIX))
+ return images
+
+ def get_next_image(self):
+ config = self._boot_config_read()
+ match = re.search(r"flash:/*(\S+)/", config['SWI'])
+ return match.group(1).replace(IMAGE_DIR_PREFIX, IMAGE_PREFIX)
+
+ def set_default_image(self, image):
+ image_path = self._swi_image_path(image)
+ self._boot_config_set(SWI=image_path, SWI_DEFAULT=image_path)
+ return True
+
+ def set_next_image(self, image):
+ image_path = self._swi_image_path(image)
+ self._boot_config_set(SWI=image_path)
+ return True
+
+ def install_image(self, image_path):
+ run_command("/usr/bin/unzip -od /tmp %s boot0" % image_path)
+ run_command("swipath=%s target_path=/host sonic_upgrade=1 . /tmp/boot0" % image_path)
+
+ def remove_image(self, image):
+ nextimage = self.get_next_image()
+ current = self.get_current_image()
+ if image == nextimage:
+ image_path = self._swi_image_path(current)
+ self._boot_config_set(SWI=image_path, SWI_DEFAULT=image_path)
+ click.echo("Set next and default boot to current image %s" % current)
+
+ image_dir = image.replace(IMAGE_PREFIX, IMAGE_DIR_PREFIX)
+ click.echo('Removing image root filesystem...')
+ subprocess.call(['rm','-rf', os.path.join(HOST_PATH, image_dir)])
+ click.echo('Image removed')
+
+ def get_binary_image_version(self, image_path):
+ try:
+ version = subprocess.check_output(['/usr/bin/unzip', '-qop', image_path, '.imagehash'])
+ except subprocess.CalledProcessError:
+ return None
+ return IMAGE_PREFIX + version.strip()
+
+ def verify_binary_image(self, image_path):
+ try:
+ subprocess.check_call(['/usr/bin/unzip', '-tq', image_path])
+ # TODO: secureboot check signature
+ except subprocess.CalledProcessError:
+ return False
+ return True
+
+ @classmethod
+ def detect(cls):
+ with open('/proc/cmdline') as f:
+ return 'Aboot=' in f.read()

sonic_installer/bootloader/bootloader.py

@@ -0,0 +1,50 @@
+"""
+Abstract Bootloader class
+"""
+
+class Bootloader(object):
+
+ NAME = None
+ DEFAULT_IMAGE_PATH = None
+
+ def get_current_image(self):
+ """returns name of the current image"""
+ raise NotImplementedError
+
+ def get_next_image(self):
+ """returns name of the next image"""
+ raise NotImplementedError
+
+ def get_installed_images(self):
+ """returns list of installed images"""
+ raise NotImplementedError
+
+ def set_default_image(self, image):
+ """set default image to boot from"""
+ raise NotImplementedError
+
+ def set_next_image(self, image):
+ """set next image to boot from"""
+ raise NotImplementedError
+
+ def install_image(self, image_path):
+ """install new image"""
+ raise NotImplementedError
+
+ def remove_image(self, image):
+ """remove existing image"""
+ raise NotImplementedError
+
+ def get_binary_image_version(self, image_path):
+ """returns the version of the image"""
+ raise NotImplementedError
+
+ def verify_binary_image(self, image_path):
+ """verify that the image is supported by the bootloader"""
+ raise NotImplementedError
+
+ @classmethod
+ def detect(cls):
+ """returns True if the bootloader is in use"""
+ return False
+

sonic_installer/bootloader/grub.py

@@ -0,0 +1,86 @@
+"""
+Bootloader implementation for grub based platforms
+"""
+
+import os
+import re
+import subprocess
+
+import click
+
+from ..common import (
+ HOST_PATH,
+ IMAGE_DIR_PREFIX,
+ IMAGE_PREFIX,
+ run_command,
+)
+from .onie import OnieInstallerBootloader
+
+class GrubBootloader(OnieInstallerBootloader):
+
+ NAME = 'grub'
+
+ def get_installed_images(self):
+ images = []
+ config = open(HOST_PATH + '/grub/grub.cfg', 'r')
+ for line in config:
+ if line.startswith('menuentry'):
+ image = line.split()[1].strip("'")
+ if IMAGE_PREFIX in image:
+ images.append(image)
+ config.close()
+ return images
+
+ def get_next_image(self):
+ images = self.get_installed_images()
+ grubenv = subprocess.check_output(["/usr/bin/grub-editenv", HOST_PATH + "/grub/grubenv", "list"])
+ m = re.search(r"next_entry=(\d+)", grubenv)
+ if m:
+ next_image_index = int(m.group(1))
+ else:
+ m = re.search(r"saved_entry=(\d+)", grubenv)
+ if m:
+ next_image_index = int(m.group(1))
+ else:
+ next_image_index = 0
+ return images[next_image_index]
+
+ def set_default_image(self, image):
+ images = self.get_installed_images()
+ command = 'grub-set-default --boot-directory=' + HOST_PATH + ' ' + str(images.index(image))
+ run_command(command)
+ return True
+
+ def set_next_image(self, image):
+ images = self.get_installed_images()
+ command = 'grub-reboot --boot-directory=' + HOST_PATH + ' ' + str(images.index(image))
+ run_command(command)
+ return True
+
+ def install_image(self, image_path):
+ run_command("bash " + image_path)
+ run_command('grub-set-default --boot-directory=' + HOST_PATH + ' 0')
+
+ def remove_image(self, image):
+ click.echo('Updating GRUB...')
+ config = open(HOST_PATH + '/grub/grub.cfg', 'r')
+ old_config = config.read()
+ menuentry = re.search("menuentry '" + image + "[^}]*}", old_config).group()
+ config.close()
+ config = open(HOST_PATH + '/grub/grub.cfg', 'w')
+ # remove menuentry of the image in grub.cfg
+ config.write(old_config.replace(menuentry, ""))
+ config.close()
+ click.echo('Done')
+
+ image_dir = image.replace(IMAGE_PREFIX, IMAGE_DIR_PREFIX)
+ click.echo('Removing image root filesystem...')
+ subprocess.call(['rm','-rf', HOST_PATH + '/' + image_dir])
+ click.echo('Done')
+
+ run_command('grub-set-default --boot-directory=' + HOST_PATH + ' 0')
+ click.echo('Image removed')
+
+ @classmethod
+ def detect(cls):
+ return os.path.isfile(os.path.join(HOST_PATH, 'grub/grub.cfg'))

sonic_installer/bootloader/onie.py

@@ -0,0 +1,48 @@
+"""
+Common logic for bootloaders using an ONIE installer image
+"""
+
+import os
+import re
+import signal
+import subprocess
+
+from ..common import (
+ IMAGE_DIR_PREFIX,
+ IMAGE_PREFIX,
+)
+from .bootloader import Bootloader
+
+# Needed to prevent "broken pipe" error messages when piping
+# output of multiple commands using subprocess.Popen()
+def default_sigpipe():
+ signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+
+class OnieInstallerBootloader(Bootloader): # pylint: disable=abstract-method
+
+ DEFAULT_IMAGE_PATH = '/tmp/sonic_image'
+
+ def get_current_image(self):
+ cmdline = open('/proc/cmdline', 'r')
+ current = re.search(r"loop=(\S+)/fs.squashfs", cmdline.read()).group(1)
+ cmdline.close()
+ return current.replace(IMAGE_DIR_PREFIX, IMAGE_PREFIX)
+
+ def get_binary_image_version(self, image_path):
+ """returns the version of the image"""
+ p1 = subprocess.Popen(["cat", "-v", image_path], stdout=subprocess.PIPE, preexec_fn=default_sigpipe)
+ p2 = subprocess.Popen(["grep", "-m 1", "^image_version"], stdin=p1.stdout, stdout=subprocess.PIPE, preexec_fn=default_sigpipe)
+ p3 = subprocess.Popen(["sed", "-n", r"s/^image_version=\"\(.*\)\"$/\1/p"], stdin=p2.stdout, stdout=subprocess.PIPE, preexec_fn=default_sigpipe)
+
+ stdout = p3.communicate()[0]
+ p3.wait()
+ version_num = stdout.rstrip('\n')
+
+ # If we didn't read a version number, this doesn't appear to be a valid SONiC image file
+ if not version_num:
+ return None
+
+ return IMAGE_PREFIX + version_num
+
+ def verify_binary_image(self, image_path):
+ return os.path.isfile(image_path)