#!/usr/bin/env python3
# This script will either prefix all symlink values with the string
# "/rsyncd-munged/" or remove that prefix.
import os, sys, argparse
SYMLINK_PREFIX = '/rsyncd-munged/'
PREFIX_LEN = len(SYMLINK_PREFIX)
def main():
for arg in args.names:
if os.path.islink(arg):
process_one_arg(arg)
elif os.path.isdir(arg):
for fn in find_symlinks(arg):
process_one_arg(fn)
else:
print("Arg is not a symlink or a dir:", arg, file=sys.stderr)
def find_symlinks(path):
for entry in os.scandir(path):
if entry.is_symlink():
yield entry.path
elif entry.is_dir(follow_symlinks=False):
yield from find_symlinks(entry.path)
def process_one_arg(fn):
lnk = os.readlink(fn)
if args.unmunge:
if not lnk.startswith(SYMLINK_PREFIX):
return
lnk = lnk[PREFIX_LEN:]
while args.all and lnk.startswith(SYMLINK_PREFIX):
lnk = lnk[PREFIX_LEN:]
else:
if not args.all and lnk.startswith(SYMLINK_PREFIX):
return
lnk = SYMLINK_PREFIX + lnk
try:
os.unlink(fn)
except OSError as e:
print("Unable to unlink symlink:", str(e), file=sys.stderr)
return
try:
os.symlink(lnk, fn)
except OSError as e:
print("Unable to recreate symlink", fn, '->', lnk + ':', str(e), file=sys.stderr)
return
print(fn, '->', lnk)
if __name__ == '__main__':
our_desc = """\
Adds or removes the %s prefix to/from the start of each symlink's value.
When given the name of a directory, affects all the symlinks in that directory hierarchy.
""" % SYMLINK_PREFIX
epilog = 'See the "munge symlinks" option in the rsyncd.conf manpage for more details.'
parser = argparse.ArgumentParser(description=our_desc, epilog=epilog, add_help=False)
uniq_group = parser.add_mutually_exclusive_group()
uniq_group.add_argument('--munge', action='store_true', help="Add the prefix to symlinks (the default).")
uniq_group.add_argument('--unmunge', action='store_true', help="Remove the prefix from symlinks.")
parser.add_argument('--all', action='store_true', help="Always adds the prefix when munging (even if already munged) or removes multiple instances of the prefix when unmunging.")
parser.add_argument('--help', '-h', action='help', help="Output this help message and exit.")
parser.add_argument('names', metavar='NAME', nargs='+', help="One or more directories and/or symlinks to process.")
args = parser.parse_args()
main()
# vim: sw=4 et
