From ec3be7d441b7bc1888186c05db6e6b46abe63879 Mon Sep 17 00:00:00 2001
From: Rob Austein <sra@hactrn.net>
Date: Fri, 18 Sep 2015 01:38:53 -0400
Subject: MUTEX callbacks via ctypes.  Beware of Garbage Collector.

---
 scripts/py11-test.py | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 71 insertions(+), 1 deletion(-)

(limited to 'scripts')

diff --git a/scripts/py11-test.py b/scripts/py11-test.py
index 8e189e3..a5e9c88 100644
--- a/scripts/py11-test.py
+++ b/scripts/py11-test.py
@@ -2,6 +2,7 @@
 # doodles figuring out what else py11 should be automating for us.
 
 from py11 import *
+from struct import pack, unpack
 
 def show_token(i, t, strip = True):
   print "Token in slot #%d:" % i
@@ -66,7 +67,76 @@ ec_curve_oid_p521 = "".join(chr(i) for i in (0x06, 0x05, 0x2b, 0x81, 0x04, 0x00,
 
 p11 = PKCS11("./libpkcs11.so")
 
-p11.C_Initialize(CKF_OS_LOCKING_OK)
+if False:
+  print "Not using MUTEXes at all"
+  p11.C_Initialize()
+
+elif True:
+  print "Using OS MUTEXes"
+  p11.C_Initialize(CKF_OS_LOCKING_OK)
+
+else:
+  print "Using our own pseudo-MUTEXes"
+
+  # This class probably belongs in the library.
+
+  class Mutexes(object):
+
+    format = "=L"
+    length = len(pack(format, 0))
+
+    def __init__(self, verbose = True, flags = 0):
+      self.init_args = (flags, self.create, self.destroy, self.lock, self.unlock)
+      self.next_mutex = 0
+      self.mutexes = {}
+      self.verbose = verbose
+
+    def find(self):
+      if len(self.mutexes) > 0xFFFFFFFF:
+        raise RuntimeError
+      while self.next_mutex in self.mutexes:
+        self.next_mutex = (self.next_mutex + 1) & 0xFFFFFFFF
+
+    def encode(self, n):
+      return (CK_BYTE * self.length)(*pack(self.format, n))
+
+    def decode(self, m):
+      return unpack(self.format, m[:self.length])[0]
+
+    def create(self, mm):
+      self.find()
+      if self.verbose:
+        print "Creating mutex", self.next_mutex
+      m = self.encode(self.next_mutex)
+      self.mutexes[self.next_mutex] = [False, m]
+      mm[0] = m
+      return CKR_OK
+
+    def destroy(self, m):
+      mutex = self.decode(m)
+      if self.verbose:
+        print "Destroying mutex", mutex
+      del self.mutexes[mutex]
+      return CKR_OK
+
+    def lock(self, m):
+      mutex = self.decode(m)
+      if self.verbose:
+        print "Locking mutex", mutex
+      self.mutexes[mutex][0] = True
+      return CKR_OK
+
+    def unlock(self, m):
+      mutex = self.decode(m)
+      if self.verbose:
+        print "Unlocking mutex", mutex
+      self.mutexes[mutex][0] = False
+      return CKR_OK
+
+  mutexes = Mutexes()
+  p11.C_Initialize(*mutexes.init_args)
+
+# Dun with MUTEX insanit and C_Initialize() call
 
 slots = p11.C_GetSlotList()
 
-- 
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