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# This code is stolen directly from lxd-images, for expediency's sake.
import atexit
import hashlib
import io
import json
import os
import shutil
import subprocess
import tarfile
import tempfile
import uuid
def find_on_path(command):
"""Is command on the executable search path?"""
if 'PATH' not in os.environ:
return False
path = os.environ['PATH']
for element in path.split(os.pathsep):
if not element:
continue
filename = os.path.join(element, command)
if os.path.isfile(filename) and os.access(filename, os.X_OK):
return True
return False
class Busybox(object):
workdir = None
def __init__(self):
# Create our workdir
self.workdir = tempfile.mkdtemp()
def cleanup(self):
if self.workdir:
shutil.rmtree(self.workdir)
def create_tarball(self, split=False):
xz = "pxz" if find_on_path("pxz") else "xz"
destination_tar = os.path.join(self.workdir, "busybox.tar")
target_tarball = tarfile.open(destination_tar, "w:")
if split:
destination_tar_rootfs = os.path.join(self.workdir,
"busybox.rootfs.tar")
target_tarball_rootfs = tarfile.open(destination_tar_rootfs, "w:")
metadata = {'architecture': os.uname()[4],
'creation_date': int(os.stat("/bin/busybox").st_ctime),
'properties': {
'os': "Busybox",
'architecture': os.uname()[4],
'description': "Busybox %s" % os.uname()[4],
'name': "busybox-%s" % os.uname()[4],
# Don't overwrite actual busybox images.
'obfuscate': str(uuid.uuid4()), },
}
# Add busybox
with open("/bin/busybox", "rb") as fd:
busybox_file = tarfile.TarInfo()
busybox_file.size = os.stat("/bin/busybox").st_size
busybox_file.mode = 0o755
if split:
busybox_file.name = "bin/busybox"
target_tarball_rootfs.addfile(busybox_file, fd)
else:
busybox_file.name = "rootfs/bin/busybox"
target_tarball.addfile(busybox_file, fd)
# Add symlinks
busybox = subprocess.Popen(["/bin/busybox", "--list-full"],
stdout=subprocess.PIPE,
universal_newlines=True)
busybox.wait()
for path in busybox.stdout.read().split("\n"):
if not path.strip():
continue
symlink_file = tarfile.TarInfo()
symlink_file.type = tarfile.SYMTYPE
symlink_file.linkname = "/bin/busybox"
if split:
symlink_file.name = "%s" % path.strip()
target_tarball_rootfs.addfile(symlink_file)
else:
symlink_file.name = "rootfs/%s" % path.strip()
target_tarball.addfile(symlink_file)
# Add directories
for path in ("dev", "mnt", "proc", "root", "sys", "tmp"):
directory_file = tarfile.TarInfo()
directory_file.type = tarfile.DIRTYPE
if split:
directory_file.name = "%s" % path
target_tarball_rootfs.addfile(directory_file)
else:
directory_file.name = "rootfs/%s" % path
target_tarball.addfile(directory_file)
# Add the metadata file
metadata_yaml = json.dumps(metadata, sort_keys=True,
indent=4, separators=(',', ': '),
ensure_ascii=False).encode('utf-8') + b"\n"
metadata_file = tarfile.TarInfo()
metadata_file.size = len(metadata_yaml)
metadata_file.name = "metadata.yaml"
target_tarball.addfile(metadata_file,
io.BytesIO(metadata_yaml))
# Add an /etc/inittab; this is to work around:
# http://lists.busybox.net/pipermail/busybox/2015-November/083618.html
# Basically, since there are some hardcoded defaults that misbehave, we
# just pass an empty inittab so those aren't applied, and then busybox
# doesn't spin forever.
inittab = tarfile.TarInfo()
inittab.size = 1
inittab.name = "/rootfs/etc/inittab"
target_tarball.addfile(inittab, io.BytesIO(b"\n"))
target_tarball.close()
if split:
target_tarball_rootfs.close()
# Compress the tarball
r = subprocess.call([xz, "-9", destination_tar])
if r:
raise Exception("Failed to compress: %s" % destination_tar)
if split:
r = subprocess.call([xz, "-9", destination_tar_rootfs])
if r:
raise Exception("Failed to compress: %s" %
destination_tar_rootfs)
return destination_tar + ".xz", destination_tar_rootfs + ".xz"
else:
return destination_tar + ".xz"
def create_busybox_image():
busybox = Busybox()
atexit.register(busybox.cleanup)
path = busybox.create_tarball()
with open(path, "rb") as fd:
fingerprint = hashlib.sha256(fd.read()).hexdigest()
return path, fingerprint
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