/usr/lib/python3/dist-packages/provisioningserver/boot/tftppath.py is in python3-maas-provisioningserver 2.0.0~beta3+bzr4941-0ubuntu1.
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# GNU Affero General Public License version 3 (see the file LICENSE).
"""Construct TFTP paths for boot files."""
__all__ = [
'compose_image_path',
'list_boot_images',
'list_subdirs',
'locate_tftp_path',
]
import errno
from itertools import chain
import os.path
from provisioningserver.drivers.osystem import (
BOOT_IMAGE_PURPOSE,
OperatingSystemRegistry,
)
from provisioningserver.import_images.boot_image_mapping import (
BootImageMapping,
)
from provisioningserver.import_images.helpers import ImageSpec
from provisioningserver.logger import get_maas_logger
maaslog = get_maas_logger("tftp")
def compose_image_path(osystem, arch, subarch, release, label):
"""Compose the TFTP path for a PXE kernel/initrd directory.
The path returned is relative to the TFTP root, as it would be
identified by clients on the network.
:param osystem: Operating system.
:param arch: Main machine architecture.
:param subarch: Sub-architecture, or "generic" if there is none.
:param release: Operating system release, e.g. "precise".
:param label: Release label, e.g. "release" or "alpha-2".
:return: Path for the corresponding image directory (containing a
kernel and initrd) as exposed over TFTP.
"""
# This is a TFTP path, not a local filesystem path, so hard-code the slash.
return '/'.join([osystem, arch, subarch, release, label])
def locate_tftp_path(path, tftproot):
"""Return the local filesystem path corresponding to `path`.
The return value gives the filesystem path where you'd have to put
a file if you wanted it made available over TFTP as `path`.
:param path: Path as used in the TFTP protocol for which you want the
local filesystem equivalent. Pass `None` to get the root of the TFTP
hierarchy.
:param tftproot: The TFTP root directory.
"""
if path is None:
return tftproot
return os.path.join(tftproot, path.lstrip('/'))
def is_visible_subdir(directory, subdir):
"""Is `subdir` a non-hidden sub-directory of `directory`?"""
if subdir.startswith('.'):
return False
else:
return os.path.isdir(os.path.join(directory, subdir))
def list_subdirs(directory):
"""Return a list of non-hidden directories in `directory`."""
return [
subdir
for subdir in os.listdir(directory)
if is_visible_subdir(directory, subdir)
]
def extend_path(directory, path):
"""Dig one directory level deeper on `os.path.join(directory, *path)`.
If `path` is a list of consecutive path elements drilling down from
`directory`, return a list of sub-directory paths leading one step
further down.
:param directory: Base directory that `path` is relative to.
:param path: A path to a subdirectory of `directory`, represented as
a list of path elements relative to `directory`.
:return: A list of paths that go one sub-directory level further
down from `path`.
"""
return [
path + [subdir]
for subdir in list_subdirs(os.path.join(directory, *path))]
def drill_down(directory, paths):
"""Find the extensions of `paths` one level deeper into the filesystem.
:param directory: Base directory that each path in `paths` is relative to.
:param paths: A list of "path lists." Each path list is a list of
path elements drilling down into the filesystem from `directory`.
:return: A list of paths, each of which drills one level deeper down into
the filesystem hierarchy than the originals in `paths`.
"""
return list(chain.from_iterable(
extend_path(directory, path) for path in paths))
def extract_metadata(metadata, params):
"""Examine the maas.meta file for any required metadata.
:param metadata: contents of the maas.meta file
:param params: A dict of path components for the image
(architecture, subarchitecture, release and label).
:return: a dict of name/value metadata pairs. Currently, only
"subarches" is extracted.
"""
mapping = BootImageMapping.load_json(metadata)
image = ImageSpec(
os=params["osystem"],
arch=params["architecture"],
subarch=params["subarchitecture"],
release=params["release"],
label=params["label"],
)
try:
# On upgrade from 1.5 to 1.6, the subarches does not exist in the
# maas.meta file . Without this catch boot images will fail to
# report until the boot images are imported again.
subarches = mapping.mapping[image]['subarches']
except KeyError:
return {}
return dict(supported_subarches=subarches)
def extract_image_params(path, maas_meta):
"""Represent a list of TFTP path elements as a list of boot-image dicts.
:param path: Tuple or list that consists of a full [osystem, architecture,
subarchitecture, release] that identify a kind of boot for which we
may need an image.
:param maas_meta: Contents of the maas.meta file. This may be an
empty string.
:return: A list of dicts, each of which may also include additional
items of meta-data that are not elements in the path, such as
"subarches".
"""
osystem, arch, subarch, release, label = path
osystem_obj = OperatingSystemRegistry.get_item(osystem, default=None)
if osystem_obj is None:
return []
purposes = osystem_obj.get_boot_image_purposes(
arch, subarch, release, label)
# Expand the path into a list of dicts, one for each boot purpose.
params = []
for purpose in purposes:
image = dict(
osystem=osystem, architecture=arch, subarchitecture=subarch,
release=release, label=label, purpose=purpose)
if purpose == BOOT_IMAGE_PURPOSE.XINSTALL:
xinstall_path, xinstall_type = osystem_obj.get_xinstall_parameters(
arch, subarch, release, label)
image['xinstall_path'] = xinstall_path
image['xinstall_type'] = xinstall_type
else:
image['xinstall_path'] = ''
image['xinstall_type'] = ''
params.append(image)
# Merge in the meta-data.
for image_dict in params:
metadata = extract_metadata(maas_meta, image_dict)
image_dict.update(metadata)
return params
def maas_meta_file_path(tftproot):
"""Return a string containing the full path to maas.meta."""
return os.path.join(tftproot, 'maas.meta')
def maas_meta_last_modified(tftproot):
"""Return time of last modification of maas.meta.
The time is the same as returned from getmtime() (seconds since epoch),
or None if the file doesn't exist.
:param tftproot: The TFTP root path.
"""
meta_file = maas_meta_file_path(tftproot)
try:
return os.path.getmtime(meta_file)
except OSError as e:
if e.errno == errno.ENOENT:
return None
raise
def list_boot_images(tftproot):
"""List the available boot images.
:param tftproot: TFTP root directory.
:return: A list of dicts, describing boot images as consumed by the
`report_boot_images` API call.
"""
# The sub-directories directly under tftproot, if they contain
# images, represent operating systems.
try:
potential_osystems = list_subdirs(tftproot)
except OSError as exception:
if exception.errno == errno.ENOENT:
# Directory does not exist, so return empty list.
maaslog.warning(
"No boot images have been imported from the region.")
return []
# Other error. Propagate.
raise
# Starting point for iteration: paths that contain only the
# top-level subdirectory of tftproot, i.e. the architecture name.
paths = [[subdir] for subdir in potential_osystems]
# Extend paths deeper into the filesystem, through the levels that
# represent architecture, sub-architecture, release, and label.
# Any directory that doesn't extend this deep isn't a boot image.
for level in ['arch', 'subarch', 'release', 'label']:
paths = drill_down(tftproot, paths)
# Get hold of image meta-data stored in the maas.meta file.
metadata = get_image_metadata(tftproot)
# Each path we find this way should be a boot image.
# This gets serialised to JSON, so we really have to return a list, not
# just any iterable.
return list(chain.from_iterable(
extract_image_params(path, metadata) for path in paths))
def get_image_metadata(tftproot):
meta_file_path = maas_meta_file_path(tftproot)
try:
with open(meta_file_path, "r", encoding="utf-8") as f:
metadata = f.read()
except IOError as e:
if e.errno != errno.ENOENT:
# Unexpected error, propagate.
raise
# No meta file (yet), it means no import has run so just skip
# it.
metadata = ""
return metadata
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