Move code finding native libraries to util.py.

ldx · ldx · commit 6c0752b2da58 · 2013-03-04T10:53:08.000+01:00
Now we use util.find_library() to find both system libraries and our
libxtwrapper.so.
diff --git a/iptc/ip4tc.py b/iptc/ip4tc.py
@@ -6,8 +6,8 @@
 import socket
 import struct
 import weakref
-import ctypes.util
 
+from util import find_library
 from xtables import (XT_INV_PROTO, NFPROTO_IPV4, XTablesError, xtables,
                      xt_align, xt_counters, xt_entry_target, xt_entry_match)
 
@@ -83,12 +83,7 @@ class IPTCError(Exception):
     """
 
 
-_libiptc_file = ctypes.util.find_library("ip4tc")
-if not _libiptc_file:
-    _libiptc_file = ctypes.util.find_library("iptc")
-if not _libiptc_file:
-    raise IPTCError("error: libiptc/libip4tc not found")
-_libiptc = ct.CDLL(_libiptc_file, use_errno=True)
+_libiptc = find_library("ip4tc", "iptc")  # old iptables versions use iptc
 
 
 class iptc(object):
diff --git a/iptc/ip6tc.py b/iptc/ip6tc.py
@@ -3,11 +3,10 @@
 import ctypes as ct
 import socket
 import weakref
-import ctypes.util
 
 from ip4tc import Rule, Table, IPTCError
+from util import find_library, load_kernel
 from xtables import (XT_INV_PROTO, NFPROTO_IPV6, xt_align, xt_counters)
-from util import load_kernel
 
 __all__ = ["Table6", "Rule6"]
 
@@ -82,10 +81,7 @@ class ip6t_entry(ct.Structure):
                 ("elems", ct.c_ubyte * 0)]       # the matches then the target
 
 
-_libiptc_file = ctypes.util.find_library("ip6tc")
-if not _libiptc_file:
-    raise IPTCError("error: libip6tc not found")
-_libiptc = ct.CDLL(_libiptc_file, use_errno=True)
+_libiptc = find_library("ip6tc", "iptc")  # old iptables versions use iptc
 
 
 class ip6tc(object):
diff --git a/iptc/util.py b/iptc/util.py
@@ -1,3 +1,5 @@
+import ctypes
+import ctypes.util
 from subprocess import Popen, PIPE
 
 
@@ -26,3 +28,39 @@ def load_kernel(name, exc_if_failed=False):
             err = err[:-1]
         if exc_if_failed:
             raise Exception(err)
+
+
+def _find_library(name):
+    p = ctypes.util.find_library(name)
+    if p:
+        lib = ctypes.CDLL(p, mode=ctypes.RTLD_GLOBAL)
+        return lib
+
+    # probably we have been installed in a virtualenv
+    import os
+    from distutils.sysconfig import get_python_lib
+    try:
+        lib = ctypes.CDLL(os.path.join(get_python_lib(), 'lib%s.so' % (name)),
+                          mode=ctypes.RTLD_GLOBAL)
+        return lib
+    except:
+        pass
+
+    import sys
+    for p in sys.path:
+        try:
+            lib = ctypes.CDLL(os.path.join(p, 'lib%s.so' % (name)),
+                              mode=ctypes.RTLD_GLOBAL)
+            return lib
+        except:
+            pass
+    return None
+
+
+def find_library(*names):
+    lib = None
+    for name in names:
+        lib = _find_library(name)
+        if lib is not None:
+            break
+    return lib
diff --git a/iptc/xtables.py b/iptc/xtables.py
@@ -1,10 +1,11 @@
 # -*- coding: utf-8 -*-
 
 import ctypes as ct
-import ctypes.util
 import weakref
 import version
 
+from util import find_library
+
 XT_INV_PROTO = 0x40  # invert the sense of PROTO
 
 NFPROTO_UNSPEC = 0
@@ -274,42 +275,14 @@ class XTablesError(Exception):
     """Raised when an xtables call fails for some reason."""
 
 
-_libc = ct.CDLL(ctypes.util.find_library("c"))
+_libc = find_library("c")
 _optind = ct.c_long.in_dll(_libc, "optind")
 _optarg = ct.c_char_p.in_dll(_libc, "optarg")
 
+_lib_xtables = find_library("xtables")
+
+_lib_xtwrapper = find_library("xtwrapper")
 
-_lib_xtables = ct.CDLL(ctypes.util.find_library("xtables"),
-                       mode=ct.RTLD_GLOBAL)
-
-
-def _get_library(name):
-    p = ctypes.util.find_library(name)
-    if p:
-        lib = ct.CDLL(p, mode=ct.RTLD_GLOBAL)
-        return lib
-
-    # probably we have been installed in a virtualenv
-    import os
-    from distutils.sysconfig import get_python_lib
-    try:
-        lib = ct.CDLL(os.path.join(get_python_lib(), 'lib%s.so' % (name)),
-                      mode=ct.RTLD_GLOBAL)
-        return lib
-    except:
-        pass
-
-    import sys
-    for p in sys.path:
-        try:
-            lib = ct.CDLL(os.path.join(p, 'lib%s.so' % (name)),
-                          mode=ct.RTLD_GLOBAL)
-            return lib
-        except:
-            pass
-    return None
-
-_lib_xtwrapper = _get_library("xtwrapper")
 _throw = _lib_xtwrapper.throw_exception
 
 _wrap_parse = _lib_xtwrapper.wrap_parse
