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import errno
import glob
import shutil
import subprocess
import os.path
def join(*paths):
"""Like os.path.join but doesn't treat absolute RHS specially"""
return os.path.normpath("/".join(paths))
def relative(src, dest):
""" Return a relative path from src to dest.
>>> relative("/usr/bin", "/tmp/foo/bar")
../../tmp/foo/bar
>>> relative("/usr/bin", "/usr/lib")
../lib
>>> relative("/tmp", "/tmp/foo/bar")
foo/bar
"""
return os.path.relpath(dest, src)
def make_relative_symlink(path):
""" Convert an absolute symlink to a relative one """
if not os.path.islink(path):
return
link = os.readlink(path)
if not os.path.isabs(link):
return
# find the common ancestor directory
ancestor = path
depth = 0
while ancestor and not link.startswith(ancestor):
ancestor = ancestor.rpartition('/')[0]
depth += 1
if not ancestor:
print("make_relative_symlink() Error: unable to find the common ancestor of %s and its target" % path)
return
base = link.partition(ancestor)[2].strip('/')
while depth > 1:
base = "../" + base
depth -= 1
os.remove(path)
os.symlink(base, path)
def format_display(path, metadata):
""" Prepare a path for display to the user. """
rel = relative(metadata.getVar("TOPDIR", True), path)
if len(rel) > len(path):
return path
else:
return rel
def copytree(src, dst):
# We could use something like shutil.copytree here but it turns out to
# to be slow. It takes twice as long copying to an empty directory.
# If dst already has contents performance can be 15 time slower
# This way we also preserve hardlinks between files in the tree.
bb.utils.mkdirhier(dst)
cmd = 'tar -cf - -C %s -p . | tar -xf - -C %s' % (src, dst)
subprocess.check_output(cmd, shell=True, stderr=subprocess.STDOUT)
def copyhardlinktree(src, dst):
""" Make the hard link when possible, otherwise copy. """
bb.utils.mkdirhier(dst)
if os.path.isdir(src) and not len(os.listdir(src)):
return
if (os.stat(src).st_dev == os.stat(dst).st_dev):
# Need to copy directories only with tar first since cp will error if two
# writers try and create a directory at the same time
cmd = 'cd %s; find . -type d -print | tar -cf - -C %s -p --no-recursion --files-from - | tar -xf - -C %s' % (src, src, dst)
subprocess.check_output(cmd, shell=True, stderr=subprocess.STDOUT)
cmd = 'cd %s; find . -print0 | cpio --null -pdlu %s' % (src, dst)
subprocess.check_output(cmd, shell=True, stderr=subprocess.STDOUT)
else:
copytree(src, dst)
def remove(path, recurse=True):
"""Equivalent to rm -f or rm -rf"""
for name in glob.glob(path):
try:
os.unlink(name)
except OSError as exc:
if recurse and exc.errno == errno.EISDIR:
shutil.rmtree(name)
elif exc.errno != errno.ENOENT:
raise
def symlink(source, destination, force=False):
"""Create a symbolic link"""
try:
if force:
remove(destination)
os.symlink(source, destination)
except OSError as e:
if e.errno != errno.EEXIST or os.readlink(destination) != source:
raise
def find(dir, **walkoptions):
""" Given a directory, recurses into that directory,
returning all files as absolute paths. """
for root, dirs, files in os.walk(dir, **walkoptions):
for file in files:
yield os.path.join(root, file)
## realpath() related functions
def __is_path_below(file, root):
return (file + os.path.sep).startswith(root)
def __realpath_rel(start, rel_path, root, loop_cnt, assume_dir):
"""Calculates real path of symlink 'start' + 'rel_path' below
'root'; no part of 'start' below 'root' must contain symlinks. """
have_dir = True
for d in rel_path.split(os.path.sep):
if not have_dir and not assume_dir:
raise OSError(errno.ENOENT, "no such directory %s" % start)
if d == os.path.pardir: # '..'
if len(start) >= len(root):
# do not follow '..' before root
start = os.path.dirname(start)
else:
# emit warning?
pass
else:
(start, have_dir) = __realpath(os.path.join(start, d),
root, loop_cnt, assume_dir)
assert(__is_path_below(start, root))
return start
def __realpath(file, root, loop_cnt, assume_dir):
while os.path.islink(file) and len(file) >= len(root):
if loop_cnt == 0:
raise OSError(errno.ELOOP, file)
loop_cnt -= 1
target = os.path.normpath(os.readlink(file))
if not os.path.isabs(target):
tdir = os.path.dirname(file)
assert(__is_path_below(tdir, root))
else:
tdir = root
file = __realpath_rel(tdir, target, root, loop_cnt, assume_dir)
try:
is_dir = os.path.isdir(file)
except:
is_dir = false
return (file, is_dir)
def realpath(file, root, use_physdir = True, loop_cnt = 100, assume_dir = False):
""" Returns the canonical path of 'file' with assuming a
toplevel 'root' directory. When 'use_physdir' is set, all
preceding path components of 'file' will be resolved first;
this flag should be set unless it is guaranteed that there is
no symlink in the path. When 'assume_dir' is not set, missing
path components will raise an ENOENT error"""
root = os.path.normpath(root)
file = os.path.normpath(file)
if not root.endswith(os.path.sep):
# letting root end with '/' makes some things easier
root = root + os.path.sep
if not __is_path_below(file, root):
raise OSError(errno.EINVAL, "file '%s' is not below root" % file)
try:
if use_physdir:
file = __realpath_rel(root, file[(len(root) - 1):], root, loop_cnt, assume_dir)
else:
file = __realpath(file, root, loop_cnt, assume_dir)[0]
except OSError as e:
if e.errno == errno.ELOOP:
# make ELOOP more readable; without catching it, there will
# be printed a backtrace with 100s of OSError exceptions
# else
raise OSError(errno.ELOOP,
"too much recursions while resolving '%s'; loop in '%s'" %
(file, e.strerror))
raise
return file
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