borg/attic/platform_linux.pyx

144 lines
4.6 KiB
Cython

import os
import re
from stat import S_ISLNK
from attic.helpers import posix_acl_use_stored_uid_gid, user2uid, group2gid
API_VERSION = 2
cdef extern from "sys/types.h":
int ACL_TYPE_ACCESS
int ACL_TYPE_DEFAULT
cdef extern from "sys/acl.h":
ctypedef struct _acl_t:
pass
ctypedef _acl_t *acl_t
int acl_free(void *obj)
acl_t acl_get_file(const char *path, int type)
acl_t acl_set_file(const char *path, int type, acl_t acl)
acl_t acl_from_text(const char *buf)
char *acl_to_text(acl_t acl, ssize_t *len)
cdef extern from "acl/libacl.h":
int acl_extended_file(const char *path)
_comment_re = re.compile(' *#.*', re.M)
def acl_use_local_uid_gid(acl):
"""Replace the user/group field with the local uid/gid if possible
"""
entries = []
for entry in acl.decode('ascii').split('\n'):
if entry:
fields = entry.split(':')
if fields[0] == 'user' and fields[1]:
fields[1] = user2uid(fields[1], fields[3])
elif fields[0] == 'group' and fields[1]:
fields[1] = group2gid(fields[1], fields[3])
entries.append(':'.join(entry.split(':')[:3]))
return ('\n'.join(entries)).encode('ascii')
cdef acl_append_numeric_ids(acl):
"""Extend the "POSIX 1003.1e draft standard 17" format with an additional uid/gid field
"""
entries = []
for entry in _comment_re.sub('', acl.decode('ascii')).split('\n'):
if entry:
type, name, permission = entry.split(':')
if name and type == 'user':
entries.append(':'.join([type, name, permission, str(user2uid(name, name))]))
elif name and type == 'group':
entries.append(':'.join([type, name, permission, str(group2gid(name, name))]))
else:
entries.append(entry)
return ('\n'.join(entries)).encode('ascii')
cdef acl_numeric_ids(acl):
"""Replace the "POSIX 1003.1e draft standard 17" user/group field with uid/gid
"""
entries = []
for entry in _comment_re.sub('', acl.decode('ascii')).split('\n'):
if entry:
type, name, permission = entry.split(':')
if name and type == 'user':
uid = str(user2uid(name, name))
entries.append(':'.join([type, uid, permission, uid]))
elif name and type == 'group':
gid = str(group2gid(name, name))
entries.append(':'.join([type, gid, permission, gid]))
else:
entries.append(entry)
return ('\n'.join(entries)).encode('ascii')
def acl_get(path, item, st, numeric_owner=False):
"""Saves ACL Entries
If `numeric_owner` is True the user/group field is not preserved only uid/gid
"""
cdef acl_t default_acl = NULL
cdef acl_t access_acl = NULL
cdef char *default_text = NULL
cdef char *access_text = NULL
p = <bytes>os.fsencode(path)
if S_ISLNK(st.st_mode) or acl_extended_file(p) <= 0:
return
if numeric_owner:
converter = acl_numeric_ids
else:
converter = acl_append_numeric_ids
try:
access_acl = acl_get_file(p, ACL_TYPE_ACCESS)
if access_acl:
access_text = acl_to_text(access_acl, NULL)
if access_text:
item[b'acl_access'] = converter(access_text)
default_acl = acl_get_file(p, ACL_TYPE_DEFAULT)
if default_acl:
default_text = acl_to_text(default_acl, NULL)
if default_text:
item[b'acl_default'] = converter(default_text)
finally:
acl_free(default_text)
acl_free(default_acl)
acl_free(access_text)
acl_free(access_acl)
def acl_set(path, item, numeric_owner=False):
"""Restore ACL Entries
If `numeric_owner` is True the stored uid/gid is used instead
of the user/group names
"""
cdef acl_t access_acl = NULL
cdef acl_t default_acl = NULL
p = <bytes>os.fsencode(path)
if numeric_owner:
converter = posix_acl_use_stored_uid_gid
else:
converter = acl_use_local_uid_gid
access_text = item.get(b'acl_access')
default_text = item.get(b'acl_default')
if access_text:
try:
access_acl = acl_from_text(<bytes>converter(access_text))
if access_acl:
acl_set_file(p, ACL_TYPE_ACCESS, access_acl)
finally:
acl_free(access_acl)
if default_text:
try:
default_acl = acl_from_text(<bytes>converter(default_text))
if default_acl:
acl_set_file(p, ACL_TYPE_DEFAULT, default_acl)
finally:
acl_free(default_acl)