symlink.py (2846B)
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 6 description = """ 7 Make a symlink. 8 """ 9 usage = "%prog [options] source[ source ...] linkname" 10 epilog = """\ 11 A symlink to source is created at linkname. If multiple sources are specified, 12 then linkname is assumed to be a directory, and will contain all the links to 13 the sources (basenames identical to their source). 14 15 On Windows, this will use hard links (mklink /H) to avoid requiring elevation. 16 This means that if the original is deleted and replaced, the link will still 17 have the old contents. 18 """ 19 20 import errno 21 import optparse 22 import os 23 import shutil 24 import subprocess 25 import sys 26 27 28 def Main(argv): 29 parser = optparse.OptionParser(usage=usage, description=description, 30 epilog=epilog) 31 parser.add_option('-f', '--force', action='store_true') 32 33 options, args = parser.parse_args(argv[1:]) 34 if len(args) < 2: 35 parser.error('at least two arguments required.') 36 37 target = args[-1] 38 sources = args[:-1] 39 for s in sources: 40 t = os.path.join(target, os.path.basename(s)) 41 if len(sources) == 1 and not os.path.isdir(target): 42 t = target 43 t = os.path.expanduser(t) 44 if os.path.realpath(t) == os.path.realpath(s): 45 continue 46 try: 47 # N.B. Python 2.x does not have os.symlink for Windows. 48 # Python 3 has os.symlink for Windows, but requires either the admin- 49 # granted privilege SeCreateSymbolicLinkPrivilege or, as of Windows 10 50 # 1703, that Developer Mode be enabled. Hard links and junctions do not 51 # require any extra privileges to create. 52 if os.name == 'nt': 53 # mklink does not tolerate /-delimited path names. 54 t = t.replace('/', '\\') 55 s = s.replace('/', '\\') 56 # N.B. This tool only handles file hardlinks, not directory junctions. 57 subprocess.check_output(['cmd.exe', '/c', 'mklink', '/H', t, s], 58 stderr=subprocess.STDOUT) 59 else: 60 os.symlink(s, t) 61 except OSError as e: 62 if e.errno == errno.EEXIST and options.force: 63 if os.path.isdir(t): 64 shutil.rmtree(t, ignore_errors=True) 65 else: 66 os.remove(t) 67 os.symlink(s, t) 68 else: 69 raise 70 except subprocess.CalledProcessError as e: 71 # Since subprocess.check_output does not return an easily checked error 72 # number, in the 'force' case always assume it is 'file already exists' 73 # and retry. 74 if options.force: 75 if os.path.isdir(t): 76 shutil.rmtree(t, ignore_errors=True) 77 else: 78 os.remove(t) 79 subprocess.check_output(e.cmd, stderr=subprocess.STDOUT) 80 else: 81 raise 82 83 84 if __name__ == '__main__': 85 sys.exit(Main(sys.argv))