diff --git a/tools/exec_util.py b/tools/exec_util.py
index 6d7677d1c..b644bb4a8 100644
--- a/tools/exec_util.py
+++ b/tools/exec_util.py
@@ -2,6 +2,7 @@
 # reserved. Use of this source code is governed by a BSD-style license that
 # can be found in the LICENSE file
 
+from __future__ import absolute_import
 from subprocess import Popen, PIPE
 import sys
 
@@ -32,8 +33,9 @@ def exec_cmd(cmd, path, input_string=None):
           shell=(sys.platform == 'win32'))
       out, err = process.communicate(input=input_string)
       ret = process.returncode
-  except IOError, (errno, strerror):
+  except IOError as e:
+    (errno, strerror) = e.args
     raise
   except:
     raise
-  return {'out': out, 'err': err, 'ret': ret}
+  return {'out': out.decode(), 'err': err.decode(), 'ret': ret}
diff --git a/tools/file_util.py b/tools/file_util.py
index edc382ba2..3c55a9924 100644
--- a/tools/file_util.py
+++ b/tools/file_util.py
@@ -2,6 +2,7 @@
 # reserved. Use of this source code is governed by a BSD-style license that
 # can be found in the LICENSE file.
 
+from __future__ import absolute_import
 from glob import iglob
 import os
 import shutil
@@ -19,7 +20,8 @@ def read_file(name, normalize=True):
       # normalize line endings
       data = data.replace("\r\n", "\n")
     return data
-  except IOError, (errno, strerror):
+  except IOError as e:
+    (errno, strerror) = e.args
     sys.stderr.write('Failed to read file ' + name + ': ' + strerror)
     raise
   else:
@@ -32,7 +34,8 @@ def write_file(name, data):
     f = open(name, 'w')
     # write the data
     f.write(data)
-  except IOError, (errno, strerror):
+  except IOError as e:
+    (errno, strerror) = e.args
     sys.stderr.write('Failed to write file ' + name + ': ' + strerror)
     raise
   else:
@@ -55,7 +58,8 @@ def copy_file(src, dst, quiet=True):
     shutil.copy2(src, dst)
     if not quiet:
       sys.stdout.write('Transferring ' + src + ' file.\n')
-  except IOError, (errno, strerror):
+  except IOError as e:
+    (errno, strerror) = e.args
     sys.stderr.write('Failed to copy file from ' + src + ' to ' + dst + ': ' +
                      strerror)
     raise
@@ -67,7 +71,8 @@ def move_file(src, dst, quiet=True):
     shutil.move(src, dst)
     if not quiet:
       sys.stdout.write('Moving ' + src + ' file.\n')
-  except IOError, (errno, strerror):
+  except IOError as e:
+    (errno, strerror) = e.args
     sys.stderr.write('Failed to move file from ' + src + ' to ' + dst + ': ' +
                      strerror)
     raise
@@ -90,7 +95,8 @@ def remove_file(name, quiet=True):
       os.remove(name)
       if not quiet:
         sys.stdout.write('Removing ' + name + ' file.\n')
-  except IOError, (errno, strerror):
+  except IOError as e:
+    (errno, strerror) = e.args
     sys.stderr.write('Failed to remove file ' + name + ': ' + strerror)
     raise
 
@@ -102,7 +108,8 @@ def copy_dir(src, dst, quiet=True):
     shutil.copytree(src, dst)
     if not quiet:
       sys.stdout.write('Transferring ' + src + ' directory.\n')
-  except IOError, (errno, strerror):
+  except IOError as e:
+    (errno, strerror) = e.args
     sys.stderr.write('Failed to copy directory from ' + src + ' to ' + dst +
                      ': ' + strerror)
     raise
@@ -115,7 +122,8 @@ def remove_dir(name, quiet=True):
       shutil.rmtree(name)
       if not quiet:
         sys.stdout.write('Removing ' + name + ' directory.\n')
-  except IOError, (errno, strerror):
+  except IOError as e:
+    (errno, strerror) = e.args
     sys.stderr.write('Failed to remove directory ' + name + ': ' + strerror)
     raise
 
@@ -127,7 +135,8 @@ def make_dir(name, quiet=True):
       if not quiet:
         sys.stdout.write('Creating ' + name + ' directory.\n')
       os.makedirs(name)
-  except IOError, (errno, strerror):
+  except IOError as e:
+    (errno, strerror) = e.args
     sys.stderr.write('Failed to create directory ' + name + ': ' + strerror)
     raise
 
diff --git a/tools/git_util.py b/tools/git_util.py
index 79db0455e..3a3abb441 100644
--- a/tools/git_util.py
+++ b/tools/git_util.py
@@ -2,6 +2,7 @@
 # reserved. Use of this source code is governed by a BSD-style license that
 # can be found in the LICENSE file
 
+from __future__ import absolute_import
 from exec_util import exec_cmd
 import os
 import sys
@@ -130,7 +131,7 @@ def git_apply_patch_file(patch_path, patch_dir):
   if sys.platform == 'win32':
     # Convert the patch to Unix line endings. This is necessary to avoid
     # whitespace errors with git apply.
-    patch_string = patch_string.replace('\r\n', '\n')
+    patch_string = patch_string.replace(b'\r\n', b'\n')
 
   # Git apply fails silently if not run relative to a respository root.
   if not is_checkout(patch_dir):
diff --git a/tools/patcher.py b/tools/patcher.py
index 942d21160..0ac98ea91 100644
--- a/tools/patcher.py
+++ b/tools/patcher.py
@@ -2,6 +2,7 @@
 # reserved. Use of this source code is governed by a BSD-style license that
 # can be found in the LICENSE file.
 
+from __future__ import absolute_import
 import pickle
 from optparse import OptionParser
 import os
@@ -54,7 +55,7 @@ def apply_patch_config():
 
   # Parse the configuration file.
   scope = {}
-  execfile(config_file, scope)
+  exec (compile(open(config_file, "rb").read(), config_file, 'exec'), scope)
   patches = scope["patches"]
 
   results = {'apply': 0, 'skip': 0, 'fail': 0}