1 files changed, 65 insertions, 0 deletions
diff --git a/tools/python/xen/xend/uuid.py b/tools/python/xen/xend/uuid.py
new file mode 100644
index 0000000000..096fef7f9f
--- /dev/null
+++ b/tools/python/xen/xend/uuid.py
@@ -0,0 +1,65 @@
+"""Universal(ly) Unique Identifiers (UUIDs).
+"""
+import commands
+import random
+
+def uuidgen(random=True):
+    """Generate a UUID using the command uuidgen.
+
+    If random is true (default) generates a random uuid.
+    If random is false generates a time-based uuid.
+    """
+    cmd = "uuidgen"
+    if random:
+        cmd += " -r"
+    else:
+        cmd += " -t"
+    return commands.getoutput(cmd)
+
+class UuidFactoryUuidgen:
+
+    """A uuid factory using uuidgen."""
+
+    def __init__(self):
+        pass
+
+    def getUuid(self):
+        return uuidgen()
+
+class UuidFactoryRandom:
+
+    """A random uuid factory."""
+
+    def __init__(self):
+        f = file("/dev/urandom", "r")
+        seed = f.read(16)
+        f.close()
+        self.rand = random.Random(seed)
+
+    def randBytes(self, n):
+        return [ self.rand.randint(0, 255) for i in range(0, n) ]
+
+    def getUuid(self):
+        bytes = self.randBytes(16)
+        # Encode the variant.
+        bytes[6] = (bytes[6] & 0x0f) | 0x40
+        bytes[8] = (bytes[8] & 0x3f) | 0x80
+        f = "%02x"
+        return ( "-".join([f*4, f*2, f*2, f*2, f*6]) % tuple(bytes) )
+
+def getFactory():
+    """Get the factory to use for creating uuids.
+    This is so it's easy to change the uuid factory.
+    For example, for testing we might want repeatable uuids
+    rather than the random ones we normally use.
+    """
+    global uuidFactory
+    try:
+        uuidFactory
+    except:
+        #uuidFactory = UuidFactoryUuidgen()
+        uuidFactory = UuidFactoryRandom()
+    return uuidFactory
+
+def getUuid():
+    return getFactory().getUuid()