Hack for Windows users to compensate for Graphviz "feature".

Recent versions of Graphviz no longer set the PATH variable on Windows.
Hence Scyther can fail to find dot.exe even though Graphviz was appropriately
installed.

This patch is a hack to try and locate dot.exe in the more common locations.
We currently have a hardcoded search through:

  C:\Program Files\Graphviz*
  C:\Program Files (x86)\Graphviz*

This is clearly fragile. Obviously, nobody should be solving Graphviz' problem
in such an ugly way. Change drives or languages and it stops working.

Until Graphviz provides at least an alternative environment variable (GVPATH?)
this hack will help the bulk of our users to get things up and running smoothly.

gui/Gui/Makeimage.py

@@ -31,6 +31,7 @@ from subprocess import Popen, PIPE
 
 """ Import scyther components """
 from Scyther import Misc as MiscScyther
+from Scyther import FindDot
 
 """ Import scyther-gui components """
 import Temporary
@@ -124,12 +125,15 @@ def makeImageDot(dotdata,attackthread=None):
         type = "png"
         ext = ".png"
 
+    # Retrieve dot command path
+    dotcommand = FindDot.findDot()
+
     # command to write to temporary file
     (fd2,fpname2) = Temporary.tempcleaned(ext)
     f = os.fdopen(fd2,'w')
 
     # Set up command
-    cmd = "dot -T%s" % (type)
+    cmd = "%s -T%s" % (dotcommand,type)
 
     # execute command
     p = Popen(cmd, shell=True, stdin=PIPE, stdout=PIPE)

gui/Scyther/FindDot.py

@@ -0,0 +1,129 @@
+"""
+	Scyther : An automatic verifier for security protocols.
+	Copyright (C) 2007-2013 Cas Cremers
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to the Free Software
+	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+"""
+
+#
+# FindDot.py
+#
+# Since version 2.31, GraphViz no longer sets the PATH environment variable on Windows.
+# The sole reason of existence for this file is to solve this issue automatically if possible.
+
+#---------------------------------------------------------------------------
+""" Import externals """
+import sys
+import os
+#---------------------------------------------------------------------------
+""" Import internals """
+import Misc
+#---------------------------------------------------------------------------
+
+DOTLOCATION = None
+
+#---------------------------------------------------------------------------
+
+def testDot(fpath):
+
+    try:
+        cmd = "%s -V" % (fpath)
+        (sts,sout,serr) = Misc.safeCommandOutput(cmd)
+        if sts != -1:
+            if "version" in sout + serr:
+                return True
+    except:
+        pass
+    
+    return False
+
+#---------------------------------------------------------------------------
+
+def scanPrefix(pf,name):
+
+    if pf.endswith("*"):
+        import glob
+
+        gl = glob.glob(pf)
+        for pf in gl:
+            for root,dirs,files in os.walk(pf):
+                for d in dirs:
+                    npf = os.path.join(root,d)
+                    res = scanPrefix(npf,name)
+                    if res != None:
+                        return res
+
+        return None
+
+    fpath = os.path.join(pf,name)
+    if len(pf) > 0:
+        fpath = "\"%s\"" % (fpath)
+    if testDot(fpath) == True:
+        return fpath
+
+    return None
+
+
+def scanLocations():
+    if sys.platform.startswith("win"):
+        prefixes = ["", \
+                    "C:\Program Files\Graphviz*", \
+                    "C:\Program Files (x86)\Graphviz*" ]
+        name = "dot.exe"
+    else:
+        prefixes = [""]
+        name = "dot"
+
+    for pf in prefixes:
+        path = scanPrefix(pf,name)
+        if path != None:
+            return path
+
+    return None
+    
+#---------------------------------------------------------------------------
+
+def findDot():
+    global DOTLOCATION
+
+    # Cache the results
+    if DOTLOCATION != None:
+        return DOTLOCATION
+
+    DOTLOCATION = scanLocations()
+    if DOTLOCATION == None:
+        Misc.panic("""
+Could not find the required 'dot' program, which is part of the Graphviz suite.
+Please install it from http://www.graphviz.org/
+
+Ubuntu users: install the 'graphviz' package.
+
+Windows users: make sure that Graphviz is installed and 
+   that the location of the 'dot' program is in
+   the PATH environment variable.
+
+Restarting your system may be needed for Scyther to locate any newly installed
+programs.
+        """)
+    return DOTLOCATION
+
+#---------------------------------------------------------------------------
+
+if __name__ == '__main__':
+    Misc.panic(findDot())
+
+#---------------------------------------------------------------------------
+
+# vim: set ts=4 sw=4 et list lcs=tab\:>-:

gui/scyther-gui.py

@@ -230,24 +230,9 @@ def CheckRequirements():
     """ Check for any required programs """
 
     """ We need 'dot', in the graphviz package """
-    failed = False
-    try:
-        (sts,sout,serr) = Misc.safeCommandOutput("dot -V")
-        output = (sout + serr).lower()
-        if output.find("graphviz") == -1:
-            failed = True
-    except OSError, ImportError:
-        failed = True
-    if failed:
-        Misc.panic("""
-Could not find the required 'dot' program, which is part of the graphviz suite.
-Please install it from http://www.graphviz.org/
+    from Scyther import FindDot
 
-Ubuntu users: install the 'graphviz' package.
-
-Restarting your system may be needed for Scyther to locate any newly installed
-programs.
-""")
+    FindDot.findDot()   # If Graphviz is not found, this function will call panic to complain.
 
 #---------------------------------------------------------------------------