X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=python%2Fovs%2Futil.py;h=cb0574bfcab5adac893684dec50b8239dfa2567a;hb=003ce655b7116d18c86a74c50391e54990346931;hp=aa4b9bc3dadb125bf5942b4265ae85cca029d564;hpb=a44d74d75294e358e501cc83fd35e6a5e50ebf0b;p=sliver-openvswitch.git

diff --git a/python/ovs/util.py b/python/ovs/util.py
index aa4b9bc3d..cb0574bfc 100644
--- a/python/ovs/util.py
+++ b/python/ovs/util.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2010, 2011 Nicira Networks
+# Copyright (c) 2010, 2011, 2012 Nicira, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,27 +17,77 @@ import os.path
 import sys
 
 PROGRAM_NAME = os.path.basename(sys.argv[0])
+EOF = -1
 
-def abs_file_name(dir, file_name):
+
+def abs_file_name(dir_, file_name):
     """If 'file_name' starts with '/', returns a copy of 'file_name'.
     Otherwise, returns an absolute path to 'file_name' considering it relative
-    to 'dir', which itself must be absolute.  'dir' may be None or the empty
+    to 'dir_', which itself must be absolute.  'dir_' may be None or the empty
     string, in which case the current working directory is used.
 
-    Returns None if 'dir' is null and getcwd() fails.
+    Returns None if 'dir_' is None and getcwd() fails.
 
     This differs from os.path.abspath() in that it will never change the
     meaning of a file name."""
     if file_name.startswith('/'):
         return file_name
     else:
-        if dir is None or dir == "":
+        if dir_ is None or dir_ == "":
             try:
-                dir = os.getcwd()
+                dir_ = os.getcwd()
             except OSError:
                 return None
 
-        if dir.endswith('/'):
-            return dir + file_name
+        if dir_.endswith('/'):
+            return dir_ + file_name
         else:
-            return "%s/%s" % (dir, file_name)
+            return "%s/%s" % (dir_, file_name)
+
+
+def ovs_retval_to_string(retval):
+    """Many OVS functions return an int which is one of:
+    - 0: no error yet
+    - >0: errno value
+    - EOF: end of file (not necessarily an error; depends on the function
+      called)
+
+    Returns the appropriate human-readable string."""
+
+    if not retval:
+        return ""
+    if retval > 0:
+        return os.strerror(retval)
+    if retval == EOF:
+        return "End of file"
+    return "***unknown return value: %s***" % retval
+
+
+def ovs_error(err_no, message, vlog=None):
+    """Prints 'message' on stderr and emits an ERROR level log message to
+    'vlog' if supplied.  If 'err_no' is nonzero, then it is formatted with
+    ovs_retval_to_string() and appended to the message inside parentheses.
+
+    'message' should not end with a new-line, because this function will add
+    one itself."""
+
+    err_msg = "%s: %s" % (PROGRAM_NAME, message)
+    if err_no:
+        err_msg += " (%s)" % ovs_retval_to_string(err_no)
+
+    sys.stderr.write("%s\n" % err_msg)
+    if vlog:
+        vlog.err(err_msg)
+
+
+def ovs_fatal(*args, **kwargs):
+    """Prints 'message' on stderr and emits an ERROR level log message to
+    'vlog' if supplied.  If 'err_no' is nonzero, then it is formatted with
+    ovs_retval_to_string() and appended to the message inside parentheses.
+    Then, terminates with exit code 1 (indicating a failure).
+
+    'message' should not end with a new-line, because this function will add
+    one itself."""
+
+    ovs_error(*args, **kwargs)
+    sys.exit(1)