+}
+
+# figure out which repos to act on
+sub selectrepos {
+ my @repos;
+ foreach my $repo (repolist()) {
+ my $topdir=$repo->{topdir};
+ my $subdir=$repo->{subdir};
+
+ next if $subdir eq 'DEFAULT';
+ my $dir=($subdir =~/^\//) ? $subdir : $topdir.$subdir;
+ my $d=$directory;
+ $dir.="/" unless $dir=~/\/$/;
+ $d.="/" unless $d=~/\/$/;
+ next if $dir ne $d && $dir !~ /^\Q$d\E/;
+ if (defined $max_depth) {
+ my @a=split('/', $dir);
+ my @b=split('/', $d);
+ do { } while (@a && @b && shift(@a) eq shift(@b));
+ next if @a > $max_depth || @b > $max_depth;
+ }
+ push @repos, [$dir, $topdir, $subdir];
+ }
+ if (! @repos) {
+ # fallback to find a leaf repo
+ foreach my $repo (reverse repolist()) {
+ my $topdir=$repo->{topdir};
+ my $subdir=$repo->{subdir};
+
+ next if $subdir eq 'DEFAULT';
+ my $dir=($subdir =~/^\//) ? $subdir : $topdir.$subdir;
+ my $d=$directory;
+ $dir.="/" unless $dir=~/\/$/;
+ $d.="/" unless $d=~/\/$/;
+ if ($d=~/^\Q$dir\E/) {
+ push @repos, [$dir, $topdir, $subdir];
+ last;
+ }
+ }
+ $no_chdir=1;
+ }
+ return @repos;
+}
+
+sub expandenv {
+ my $val=shift;
+
+
+ if ($val=~/\$/) {
+ $val=`echo "$val"`;
+ chomp $val;
+ }
+
+ return $val;
+}
+
+my %trusted;
+sub is_trusted_config {
+ my $config=shift; # must be abs_pathed already
+
+ # We always trust ~/.mrconfig.
+ return 1 if $config eq abs_path("$ENV{HOME}/.mrconfig");
+
+ my $trustfile=$ENV{HOME}."/.mrtrust";
+
+ if (! -e $trustfile) {
+ print "mr: Assuming $config is trusted.\n";
+ print "mr: For better security, you are encouraged to create ~/.mrtrust\n";
+ print "mr: and list all trusted mrconfig files in it.\n";
+ return 1;
+ }
+
+ if (! %trusted) {
+ $trusted{"$ENV{HOME}/.mrconfig"}=1;
+ open (TRUST, "<", $trustfile) || die "$trustfile: $!";
+ while (<TRUST>) {
+ chomp;
+ s/^~\//$ENV{HOME}\//;
+ $trusted{abs_path($_)}=1;
+ }
+ 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] && $twords[$c] eq $words[$c]) {
+ $match=1;
+ }
+ else {
+ $match=0;
+ }
+ }
+ return 1 if $match;
+ }
+
+ return 0;
+}