def copytree(src, dest, preserve=True):
'''Copy a tree of files using cp -a, thus preserving modes, timestamps,
links, acls, sparse files, xattrs, selinux contexts, etc.
If preserve is False, uses cp -R (useful for modeless filesystems)
raises CalledProcessError if copy fails.'''
logger.debug("copytree %s %s", src, dest)
cp = ["cp", "-a"
] if preserve else ["cp", "-R", "-L", "--preserve=timestamps"]
cp += [join(src, "."), os.path.abspath(dest)]
runcmd(cp)
def mkqemu_img(outfile, size, options=None):
'''use qemu-img to create a file of the given size.
options is a list of options passed to qemu-img
Default format is qcow2, override by passing "-f", fmt
in options.
'''
options = options or []
if "-f" not in options:
options.extend(["-f", "qcow2"])
runcmd(["qemu-img", "create"] + options + [outfile, str(size)])
def dm_attach(dev, size, name=None):
'''Attach a devicemapper device to the given device, with the given size.
If name is None, a random name will be chosen. Returns the device name.
raises CalledProcessError if dmsetup fails.'''
if name is None:
name = tempfile.mktemp(prefix="lorax.imgutils.", dir="")
runcmd([
"dmsetup", "create", name, "--table",
"0 %i linear %s 0" % (size / 512, dev)
])
return name
def mount_test(self):
"""Test the Mount context manager (requires loop)"""
with tempfile.NamedTemporaryFile(
prefix="lorax.test.disk.") as disk_img:
mksparse(disk_img.name, 42 * 1024**2)
runcmd([
"mkfs.ext4", "-L", "Anaconda", "-b", "4096", "-m", "0",
disk_img.name
])
with LoopDev(disk_img.name) as loopdev:
self.assertTrue(loopdev is not None)
with Mount(loopdev) as mnt:
self.assertTrue(mnt is not None)
def mount(dev, opts="", mnt=None):
'''Mount the given device at the given mountpoint, using the given opts.
opts should be a comma-separated string of mount options.
if mnt is none, a temporary directory will be created and its path will be
returned.
raises CalledProcessError if mount fails.'''
if mnt is None:
mnt = tempfile.mkdtemp(prefix="lorax.imgutils.")
logger.debug("make tmp mountdir %s", mnt)
cmd = ["mount"]
if opts:
cmd += ["-o", opts]
cmd += [dev, mnt]
runcmd(cmd)
return mnt
def umount(mnt, lazy=False, maxretry=3, retrysleep=1.0, delete=True):
'''Unmount the given mountpoint. If lazy is True, do a lazy umount (-l).
If the mount was a temporary dir created by mount, it will be deleted.
raises CalledProcessError if umount fails.'''
cmd = ["umount"]
if lazy: cmd += ["-l"]
cmd += [mnt]
count = 0
while maxretry > 0:
try:
rv = runcmd(cmd)
except CalledProcessError:
count += 1
if count == maxretry:
raise
logger.warning("failed to unmount %s. retrying (%d/%d)...", mnt,
count, maxretry)
if logger.getEffectiveLevel() <= logging.DEBUG:
fuser = execWithCapture("fuser", ["-vm", mnt])
logger.debug("fuser -vm:\n%s\n", fuser)
sleep(retrysleep)
else:
break
if delete and 'lorax.imgutils' in mnt:
os.rmdir(mnt)
logger.debug("remove tmp mountdir %s", mnt)
return (rv == 0)
def runcmd_test(self):
cmd = [
"python3", "-c",
"import sys; print('Theodor Seuss Geisel'); sys.exit(0)"
]
rc = runcmd(cmd)
self.assertEqual(rc, 0)
def loop_waitfor(loop_dev, outfile):
"""Make sure the loop device is attached to the outfile.
It seems that on rare occasions losetup can return before the /dev/loopX is
ready for use, causing problems with mkfs. This tries to make sure that the
loop device really is associated with the backing file before continuing.
Raise RuntimeError if it isn't setup after 5 tries.
"""
for _x in range(0, 5):
runcmd(["udevadm", "settle", "--timeout", "300"])
## XXX Note that losetup --list output can be truncated to 64 bytes in some
## situations. Don't use it to lookup backing file, go the other way
## and lookup the loop for the backing file. See util-linux lib/loopdev.c
## loopcxt_get_backing_file()
if get_loop_name(outfile) == os.path.basename(loop_dev):
return
# If this really is a race, give it some time to settle down
time.sleep(1)
raise RuntimeError("Unable to setup %s on %s" % (loop_dev, outfile))
def mkfsimage(fstype,
rootdir,
outfile,
size=None,
mkfsargs=None,
mountargs="",
graft=None):
'''Generic filesystem image creation function.
fstype should be a filesystem type - "mkfs.${fstype}" must exist.
graft should be a dict: {"some/path/in/image": "local/file/or/dir"};
if the path ends with a '/' it's assumed to be a directory.
Will raise CalledProcessError if something goes wrong.'''
mkfsargs = mkfsargs or []
graft = graft or {}
preserve = (fstype not in ("msdos", "vfat"))
if not size:
size = estimate_size(rootdir, graft, fstype)
with LoopDev(outfile, size) as loopdev:
try:
runcmd(["mkfs.%s" % fstype] + mkfsargs + [loopdev])
except CalledProcessError as e:
logger.error("mkfs exited with a non-zero return code: %d",
e.returncode)
logger.error(e.output)
sys.exit(e.returncode)
with Mount(loopdev, mountargs) as mnt:
if rootdir:
copytree(rootdir, mnt, preserve)
do_grafts(graft, mnt, preserve)
# Save information about filesystem usage
execWithRedirect("df", [mnt])
# Make absolutely sure that the data has been written
runcmd(["sync"])
def mkfakediskimg(disk_img):
"""Create a fake partitioned disk image
:param disk_img: Full path to a partitioned disk image
:type disk_img: str
:returns: True if it was successful, False if something went wrong
Include /boot, swap, and / partitions with fake kernel and /etc/passwd
"""
try:
mksparse(disk_img, 42 * 1024**2)
# Make a /boot, / and swap partitions on it
dev = parted.getDevice(disk_img)
disk = parted.freshDisk(dev, "gpt")
# (start, length, flags, name)
for start, length, flags, name in [
(1024**2, 1024**2, None, "boot"),
(2 * 1024**2, 2 * 1024**2, parted.PARTITION_SWAP, "swap"),
(4 * 1024**2, 38 * 1024**2, None, "root")
]:
geo = parted.Geometry(device=dev,
start=start // dev.sectorSize,
length=length // dev.sectorSize)
part = parted.Partition(disk=disk,
type=parted.PARTITION_NORMAL,
geometry=geo)
part.getPedPartition().set_name(name)
disk.addPartition(partition=part)
if flags:
part.setFlag(flags)
disk.commit()
os.sync()
except parted.PartedException:
return False
# Mount the disk's partitions
loop_devs = kpartx_disk_img(disk_img)
try:
# Format the partitions
runcmd(["mkfs.ext4", "/dev/mapper/" + loop_devs[0][0]])
runcmd(["mkswap", "/dev/mapper/" + loop_devs[1][0]])
runcmd(["mkfs.ext4", "/dev/mapper/" + loop_devs[2][0]])
# Mount the boot partition and make a fake kernel and initrd
boot_mnt = mount("/dev/mapper/" + loop_devs[0][0])
try:
mkfakebootdir(boot_mnt)
finally:
umount(boot_mnt)
# Mount the / partition and make a fake / filesystem with /etc/passwd
root_mnt = mount("/dev/mapper/" + loop_devs[2][0])
try:
mkfakerootdir(root_mnt)
finally:
umount(root_mnt)
except Exception:
return False
finally:
# Remove the disk's mounted partitions
runcmd(["kpartx", "-d", "-s", disk_img])
return True
def linktree(src, dst):
runcmd(["/bin/cp", "-alx", src, dst])