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-rw-r--r--geo-replication/syncdaemon/libcxattr.py72
1 files changed, 72 insertions, 0 deletions
diff --git a/geo-replication/syncdaemon/libcxattr.py b/geo-replication/syncdaemon/libcxattr.py
new file mode 100644
index 0000000..f0a9d22
--- /dev/null
+++ b/geo-replication/syncdaemon/libcxattr.py
@@ -0,0 +1,72 @@
+import os
+from ctypes import *
+from ctypes.util import find_library
+
+class Xattr(object):
+ """singleton that wraps the extended attribues system
+ interface for python using ctypes
+
+ Just implement it to the degree we need it, in particular
+ - we need just the l*xattr variants, ie. we never want symlinks to be
+ followed
+ - don't need size discovery for getxattr, as we always know the exact
+ sizes we expect
+ """
+
+ libc = CDLL(find_library("libc"))
+
+ @classmethod
+ def geterrno(cls):
+ return c_int.in_dll(cls.libc, 'errno').value
+
+ @classmethod
+ def raise_oserr(cls):
+ errn = cls.geterrno()
+ raise OSError(errn, os.strerror(errn))
+
+ @classmethod
+ def _query_xattr(cls, path, siz, syscall, *a):
+ if siz:
+ buf = create_string_buffer('\0' * siz)
+ else:
+ buf = None
+ ret = getattr(cls.libc, syscall)(*((path,) + a + (buf, siz)))
+ if ret == -1:
+ cls.raise_oserr()
+ if siz:
+ return buf.raw[:ret]
+ else:
+ return ret
+
+ @classmethod
+ def lgetxattr(cls, path, attr, siz=0):
+ return cls._query_xattr( path, siz, 'lgetxattr', attr)
+
+ @classmethod
+ def llistxattr(cls, path, siz=0):
+ ret = cls._query_xattr(path, siz, 'llistxattr')
+ if isinstance(ret, str):
+ ret = ret.split('\0')
+ return ret
+
+ @classmethod
+ def lsetxattr(cls, path, attr, val):
+ ret = cls.libc.lsetxattr(path, attr, val, len(val), 0)
+ if ret == -1:
+ cls.raise_oserr()
+
+ @classmethod
+ def lremovexattr(cls, path, attr):
+ ret = cls.libc.lremovexattr(path, attr)
+ if ret == -1:
+ cls.raise_oserr()
+
+ @classmethod
+ def llistxattr_buf(cls, path):
+ """listxattr variant with size discovery"""
+ size = cls.llistxattr(path)
+ if size == -1:
+ cls.raise_oserr()
+ if size == 0:
+ return []
+ return cls.llistxattr(path, size)