Viewing file:  clcagefs.py (6.16 KB) -rw-r--r--
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#!/usr/bin/python
import os
import subprocess
CAGEFS_MP_FILENAME = '/etc/cagefs/cagefs.mp'
CAGEFSCTL_TOOL = '/usr/sbin/cagefsctl'
class CagefsMpConflict(Exception):
def __init__(self, new_item, existing_item):
self._msg = "Conflict in adding '%s' to %s because of pre-existing alternative specification: '%s'" \
% (new_item, CAGEFS_MP_FILENAME, existing_item)
def __str__(self):
return self._msg
class CagefsMpItem(object):
_PREFIX_LIST = '@!%';
_PREFIX_MOUNT_RW = '';
_PREFIX_MOUNT_RO = '!';
def __init__(self, arg):
"""Constructor
:param arg: Is either path to add to cagefs.mp or a raw line is read from cagefs.mp
:param prefix: The same as adding prefix '!' to arg before passing it to ctor"""
if arg[:1] == '#': # is a comment? then init as dummy
self._path_spec = None
elif arg.strip() == '': # init as dummy for empty lines
self._path_spec = None
else:
self._path_spec = arg
def mode(self, mode):
"Specify mode as in fluent constructor"
if self.prefix() == '@' and not mode is None:
self._path_spec = "%s,%03o" % (self._path_spec, mode)
return self
def __str__(self): return self._path_spec
def _add_slash(path):
if path == '':
return '/'
if (path[-1] != '/'):
return path + '/'
return path
_add_slash = staticmethod(_add_slash)
def pre_exist_in(self, another):
adopted = CagefsMpItem._adopt(another)
# overkill: just to keep strictly to comparing NULL objects principle
if self.is_dummy() or adopted.is_dummy():
return False
this_path = CagefsMpItem._add_slash(self.path())
test_preexist_in_path = CagefsMpItem._add_slash(adopted.path())
return this_path.startswith(test_preexist_in_path)
def is_compatible_by_prefix_with(self, existing):
adopted = CagefsMpItem._adopt(existing)
# overkill: just to keep strictly to comparing NULL objects principle
if self.is_dummy() or adopted.is_dummy():
return False
if self.prefix() == adopted.prefix():
return True
prefix_compatibility_map = { CagefsMpItem._PREFIX_MOUNT_RW : [CagefsMpItem._PREFIX_MOUNT_RO] }
null_options = []
return self.prefix() in prefix_compatibility_map.get(adopted.prefix(), null_options)
def is_dummy(self): return self._path_spec is None
def _adopt(x):
if isinstance(x, CagefsMpItem):
return x
else:
return CagefsMpItem(x)
_adopt = staticmethod(_adopt)
def _cut_off_mode(path_spec):
"""Cut off mode from path spec like @/var/run/screen,777
Only one comma per path spec is allowed ;-)"""
return path_spec.split(',')[0]
_cut_off_mode = staticmethod(_cut_off_mode)
def _cut_off_prefix(path_spec): return path_spec.lstrip(CagefsMpItem._PREFIX_LIST)
_cut_off_prefix = staticmethod(_cut_off_prefix)
def path(self):
return CagefsMpItem._cut_off_prefix(CagefsMpItem._cut_off_mode(self._path_spec))
def prefix(self):
if self._path_spec != self.path():
return self._path_spec[0]
else:
return ''
def is_cagefs_present():
return os.path.exists(CAGEFS_MP_FILENAME) and \
os.path.exists(CAGEFSCTL_TOOL)
def _mk_mount_dir_setup_perm(path, mode=0755, owner_id=None, group_id=None):
if not os.path.isdir(path):
os.mkdir(path)
if not mode is None:
os.chmod(path, mode)
if (not owner_id is None) and (not group_id is None):
os.chown(path, owner_id, group_id)
def setup_mount_dir_cagefs(path, added_by, mode=0755, owner_id=None, group_id=None, prefix=''):
'''Add mount point to /etc/cagefs/cagefs.mp
:param path: Directory path to be added in cagefs.mp and mounted
from within setup_mount_dir_cagefs().
If this directory does not exist, then it is created.
:param added_by: package or component, mount dir relates to, or whatever will
stay in cagefs.mp with "# added by..." comment
:param mode: If is not None: Regardless of whether directory exists or not prior this call,
it's permissions will be set to mode.
:param owner_id: If group_id is also provided along:
Regardless of whether directory exists or not prior this call,
it's owner id will be set to.
:param group_id: If owner_id is also provided along:
Regardless of whether directory exists or not prior this call,
it's group id will be set to.
:param prefix: Mount point prefix. Default is mount as RW.
Pass '!' to add read-only mount point.
Refer CageFS section at http://docs.cloudlinux.com/ for more options.
:returns: None
Propagates native EnvironmentError if no CageFS installed or something else goes wrong.
Raises CagefsMpConflict if path is already specified in cagefs.mp, but in a way which is opposite
to mount_as_readonly param.
'''
_mk_mount_dir_setup_perm(path, mode, owner_id, owner_id)
subprocess.call([CAGEFSCTL_TOOL, "--check-mp"])
# ^^
# Hereafter we will not care if there was
# 'no newline at the end of file'
cagefs_mp = open(CAGEFS_MP_FILENAME, "r+")
try:
new_item = CagefsMpItem(prefix + path).mode(mode)
trim_nl_iter = (file_line.rstrip() for file_line in cagefs_mp)
pre_exist_option = filter(lambda x: new_item.pre_exist_in(x), trim_nl_iter)
if not pre_exist_option:
cagefs_mp.seek(0, 2) # 2: seek to the end of file
# no newline is allowed
added_by = added_by.replace("\n", " ")
print >>cagefs_mp, "# next line is added by", added_by
print >>cagefs_mp, new_item
cagefs_mp.close()
subprocess.call([CAGEFSCTL_TOOL, "--remount-all"])
elif not new_item.is_compatible_by_prefix_with(pre_exist_option[-1]):
raise CagefsMpConflict(new_item, pre_exist_option[-1])
finally:
cagefs_mp.close()
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