1#!/usr/bin/env python3 2# Copyright 2013 The Chromium Authors 3# Use of this source code is governed by a BSD-style license that can be 4# found in the LICENSE file. 5 6description = """ 7Make a symlink and optionally touch a file (to handle dependencies). 8""" 9usage = "%prog [options] source[ source ...] linkname" 10epilog = """\ 11A symlink to source is created at linkname. If multiple sources are specified, 12then linkname is assumed to be a directory, and will contain all the links to 13the sources (basenames identical to their source). 14 15On Windows, this will use hard links (mklink /H) to avoid requiring elevation. 16This means that if the original is deleted and replaced, the link will still 17have the old contents. 18""" 19 20import errno 21import optparse 22import os.path 23import shutil 24import subprocess 25import sys 26 27 28def Main(argv): 29 parser = optparse.OptionParser(usage=usage, description=description, 30 epilog=epilog) 31 parser.add_option('-f', '--force', action='store_true') 32 parser.add_option('--touch') 33 34 options, args = parser.parse_args(argv[1:]) 35 if len(args) < 2: 36 parser.error('at least two arguments required.') 37 38 target = args[-1] 39 sources = args[:-1] 40 for s in sources: 41 t = os.path.join(target, os.path.basename(s)) 42 if len(sources) == 1 and not os.path.isdir(target): 43 t = target 44 t = os.path.expanduser(t) 45 if os.path.realpath(t) == os.path.realpath(s): 46 continue 47 try: 48 # N.B. Python 2.x does not have os.symlink for Windows. 49 # Python 3 has os.symlink for Windows, but requires either the admin- 50 # granted privilege SeCreateSymbolicLinkPrivilege or, as of Windows 10 51 # 1703, that Developer Mode be enabled. Hard links and junctions do not 52 # require any extra privileges to create. 53 if os.name == 'nt': 54 # mklink does not tolerate /-delimited path names. 55 t = t.replace('/', '\\') 56 s = s.replace('/', '\\') 57 # N.B. This tool only handles file hardlinks, not directory junctions. 58 subprocess.check_output(['cmd.exe', '/c', 'mklink', '/H', t, s], 59 stderr=subprocess.STDOUT) 60 else: 61 os.symlink(s, t) 62 except OSError as e: 63 if e.errno == errno.EEXIST and options.force: 64 if os.path.isdir(t): 65 shutil.rmtree(t, ignore_errors=True) 66 else: 67 os.remove(t) 68 os.symlink(s, t) 69 else: 70 raise 71 except subprocess.CalledProcessError as e: 72 # Since subprocess.check_output does not return an easily checked error 73 # number, in the 'force' case always assume it is 'file already exists' 74 # and retry. 75 if options.force: 76 if os.path.isdir(t): 77 shutil.rmtree(t, ignore_errors=True) 78 else: 79 os.remove(t) 80 subprocess.check_output(e.cmd, stderr=subprocess.STDOUT) 81 else: 82 raise 83 84 85 if options.touch: 86 os.makedirs(os.path.dirname(options.touch), exist_ok=True) 87 with open(options.touch, 'w'): 88 pass 89 90 91if __name__ == '__main__': 92 sys.exit(Main(sys.argv)) 93