-#!/usr/bin/env python
-# Copyright (c) 2013 The Chromium Authors. All rights reserved.
+#!/usr/bin/env python3
+# Copyright 2013 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
-"""Make a symlink and optionally touch a file (to handle dependencies).
-
-Usage:
- symlink.py [options] sources... target
-
-A sym link to source is created at target. If multiple sources are specfied,
-then target is assumed to be a directory, and will contain all the links to
+description = """
+Make a symlink and optionally touch a file (to handle dependencies).
+"""
+usage = "%prog [options] source[ source ...] linkname"
+epilog = """\
+A symlink to source is created at linkname. If multiple sources are specified,
+then linkname is assumed to be a directory, and will contain all the links to
the sources (basenames identical to their source).
+
+On Windows, this will use hard links (mklink /H) to avoid requiring elevation.
+This means that if the original is deleted and replaced, the link will still
+have the old contents.
"""
import errno
import optparse
import os.path
import shutil
+import subprocess
import sys
def Main(argv):
- parser = optparse.OptionParser()
+ parser = optparse.OptionParser(usage=usage, description=description,
+ epilog=epilog)
parser.add_option('-f', '--force', action='store_true')
parser.add_option('--touch')
if len(sources) == 1 and not os.path.isdir(target):
t = target
t = os.path.expanduser(t)
- if os.path.realpath(t) == s:
+ if os.path.realpath(t) == os.path.realpath(s):
continue
try:
- os.symlink(s, t)
- except OSError, e:
+ # N.B. Python 2.x does not have os.symlink for Windows.
+ # Python 3 has os.symlink for Windows, but requires either the admin-
+ # granted privilege SeCreateSymbolicLinkPrivilege or, as of Windows 10
+ # 1703, that Developer Mode be enabled. Hard links and junctions do not
+ # require any extra privileges to create.
+ if os.name == 'nt':
+ # mklink does not tolerate /-delimited path names.
+ t = t.replace('/', '\\')
+ s = s.replace('/', '\\')
+ # N.B. This tool only handles file hardlinks, not directory junctions.
+ subprocess.check_output(['cmd.exe', '/c', 'mklink', '/H', t, s],
+ stderr=subprocess.STDOUT)
+ else:
+ os.symlink(s, t)
+ except OSError as e:
if e.errno == errno.EEXIST and options.force:
if os.path.isdir(t):
shutil.rmtree(t, ignore_errors=True)
os.symlink(s, t)
else:
raise
+ except subprocess.CalledProcessError as e:
+ # Since subprocess.check_output does not return an easily checked error
+ # number, in the 'force' case always assume it is 'file already exists'
+ # and retry.
+ if options.force:
+ if os.path.isdir(t):
+ shutil.rmtree(t, ignore_errors=True)
+ else:
+ os.remove(t)
+ subprocess.check_output(e.cmd, stderr=subprocess.STDOUT)
+ else:
+ raise
if options.touch:
- with open(options.touch, 'w') as f:
+ os.makedirs(os.path.dirname(options.touch), exist_ok=True)
+ with open(options.touch, 'w'):
pass