Convert munge-symlinks to python.

diff --git a/support/munge-symlinks b/support/munge-symlinks
index 3e5f3ad2a9276fe755d0ea0d60ab33d06e6c83ab..e7a5474167d231c1a89586a351c9ee8300e94cf3 100755 (executable)
--- a/support/munge-symlinks
+++ b/support/munge-symlinks
@@ -1,60 +1,71 @@
-#!/usr/bin/env perl
+#!/usr/bin/env python3
 # This script will either prefix all symlink values with the string
 # "/rsyncd-munged/" or remove that prefix.
 
-use strict;
-use Getopt::Long;
-
-my $SYMLINK_PREFIX = '/rsyncd-munged/';
-
-my $munge_opt;
-
-&GetOptions(
-    'munge' => sub { $munge_opt = 1 },
-    'unmunge' => sub { $munge_opt = 0 },
-    'all' => \( my $all_opt ),
-    'help|h' => \( my $help_opt ),
-) or &usage;
-
-&usage if $help_opt || !defined $munge_opt;
-
-my $munged_re = $all_opt ? qr/^($SYMLINK_PREFIX)+(?=.)/ : qr/^$SYMLINK_PREFIX(?=.)/;
-
-push(@ARGV, '.') unless @ARGV;
-
-open(PIPE, '-|', 'find', @ARGV, '-type', 'l') or die $!;
-
-while (<PIPE>) {
-    chomp;
-    my $lnk = readlink($_) or next;
-    if ($munge_opt) {
-       next if !$all_opt && $lnk =~ /$munged_re/;
-       $lnk =~ s/^/$SYMLINK_PREFIX/;
-    } else {
-       next unless $lnk =~ s/$munged_re//;
-    }
-    if (!unlink($_)) {
-       warn "Unable to unlink symlink: $_ ($!)\n";
-    } elsif (!symlink($lnk, $_)) {
-       warn "Unable to recreate symlink: $_ -> $lnk ($!)\n";
-    } else {
-       print "$_ -> $lnk\n";
-    }
-}
-
-close PIPE;
-exit;
-
-sub usage
-{
-    die <<EOT;
-Usage: munge-symlinks --munge|--unmunge [--all] [DIR|SYMLINK...]
-
---munge      Add the $SYMLINK_PREFIX prefix to symlinks if not already
-             present, or always when combined with --all.
---unmunge    Remove one $SYMLINK_PREFIX prefix from symlinks or all
-             such prefixes with --all.
-
-See the "munge symlinks" option in the rsyncd.conf manpage for more details.
-EOT
-}
+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