[Python-checkins] python/dist/src/Lib os.py,1.77,1.78

[loewis at users.sourceforge.net]

Update of /cvsroot/python/python/dist/src/Lib
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv13928/Lib

Modified Files:
	os.py 
Log Message:
Patch #934711: Expose platform-specific entropy.


Index: os.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/os.py,v
retrieving revision 1.77
retrieving revision 1.78
diff -u -d -r1.77 -r1.78
--- os.py	8 Jun 2004 08:29:32 -0000	1.77
+++ os.py	29 Aug 2004 15:46:34 -0000	1.78
@@ -656,3 +656,24 @@
                      _make_statvfs_result)
 except NameError: # statvfs_result may not exist
     pass
+
+if not _exists("urandom"):
+    _urandomfd = None   
+    def urandom(n):
+        """urandom(n) -> str
+ 
+        Return a string of n random bytes suitable for cryptographic use.
+
+        """    
+        global _urandomfd
+        if not _urandomfd:
+            try:
+                _urandomfd = open("/dev/urandom", O_RDONLY)         
+            except:
+                _urandomfd = NotImplementedError
+        if _urandomfd is NotImplementedError:
+            raise NotImplementedError("/dev/urandom (or equivalent) not found")
+        bytes = ""
+        while len(bytes) < n:
+            bytes += read(_urandomfd, n - len(bytes))
+        return bytes