syncdaemon: load xattrs from libc on-demand

This reduces startup time for invocations other than master / slave role
(kind of which now proliferates glusterd)

Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Anand Avati <avati@gluster.com>

BUG: 2780 (geo-replication operations take too much time to complete)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2780

1 files changed, 63 insertions, 0 deletions

diff --git a/xlators/features/marker/utils/syncdaemon/libcxattr.py b/xlators/features/marker/utils/syncdaemon/libcxattr.py
new file mode 100644
index 00000000000..907a16c7802
--- /dev/null
+++ b/xlators/features/marker/utils/syncdaemon/libcxattr.py
@@ -0,0 +1,63 @@
+import os
+from ctypes import *
+from ctypes.util import find_library
+
+class Xattr(object):
+
+    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):
+        size = cls.llistxattr(path)
+        if size  == -1:
+            raise_oserr()
+        return cls.llistxattr(path, size)
+
+
+