+my %trusted;
+sub is_trusted_config {
+ my $config=shift; # must be abs_pathed already
+
+ # We always trust ~/.mrconfig.
+ return 1 if $config eq abs_path($HOME_MR_CONFIG);
+
+ return 1 if $trust_all;
+
+ my $trustfile=$ENV{HOME}."/.mrtrust";
+
+ if (! %trusted) {
+ $trusted{$HOME_MR_CONFIG}=1;
+ if (open (TRUST, "<", $trustfile)) {
+ while (<TRUST>) {
+ chomp;
+ s/^~\//$ENV{HOME}\//;
+ my $d=abs_path($_);
+ $trusted{$d}=1 if defined $d;
+ }
+ close TRUST;
+ }
+ }
+
+ return $trusted{$config};
+}
+
+
+sub is_trusted_repo {
+ my $repo=shift;
+
+ # Tightly limit what is allowed in a repo name.
+ # No ../, no absolute paths, and no unusual filenames
+ # that might try to escape to the shell.
+ return $repo =~ /^[-_.+\/A-Za-z0-9]+$/ &&
+ $repo !~ /\.\./ && $repo !~ /^\//;
+}
+
+sub is_trusted_checkout {
+ my $command=shift;
+
+ # To determine if the command is safe, compare it with the
+ # *_trusted_checkout config settings. Those settings are
+ # templates for allowed commands, so make sure that each word
+ # of the command matches the corresponding word of the template.
+
+ my @words;
+ foreach my $word (split(' ', $command)) {
+ # strip quoting
+ if ($word=~/^'(.*)'$/) {
+ $word=$1;
+ }
+ elsif ($word=~/^"(.*)"$/) {
+ $word=$1;
+ }
+
+ push @words, $word;
+ }
+
+ foreach my $key (grep { /_trusted_checkout$/ }
+ keys %{$config{''}{DEFAULT}}) {
+ my @twords=split(' ', $config{''}{DEFAULT}{$key});
+ next if @words > @twords;
+
+ my $match=1;
+ my $url;
+ for (my $c=0; $c < @twords && $match; $c++) {
+ if ($twords[$c] eq '$url') {
+ # Match all the typical characters found in
+ # urls, plus @ which svn can use. Note
+ # that the "url" might also be a local
+ # directory.
+ $match=(
+ defined $words[$c] &&
+ $words[$c] =~ /^[-_.+:@\/A-Za-z0-9]+$/
+ );
+ $url=$words[$c];
+ }
+ elsif ($twords[$c] eq '$repo') {
+ # If a repo is not specified, assume it
+ # will be the last path component of the
+ # url, or something derived from it, and
+ # check that.
+ if (! defined $words[$c] && defined $url) {
+ ($words[$c])=$url=~/\/([^\/]+)\/?$/;
+ }
+
+ $match=(
+ defined $words[$c] &&
+ is_trusted_repo($words[$c])
+ );
+ }
+ elsif (defined $words[$c] && $words[$c]=~/^($twords[$c])$/) {
+ $match=1;
+ }
+ else {
+ $match=0;
+ }
+ }
+ return 1 if $match;
+ }
+
+ return 0;
+}
+