Correct an out-by-one error when earlying out ustar filenames that

are too long.  Filenames escaping this test are caught later on,
so the bug doesn't cause any breakage.

Document the correct ustar limitations in pax.  As I have no access
to the IEEE 1003.2 spec, I can only assume that the limitations
imposed are in fact correct.

Add regression tests for the filename limitations imposed by pax.

MFC after:	3 weeks

2 files changed, 99 insertions, 0 deletions

diff --git a/tools/regression/bin/pax/Makefile b/tools/regression/bin/pax/Makefile
new file mode 100644
index 0000000..dc1a317
--- /dev/null
+++ b/tools/regression/bin/pax/Makefile
@@ -0,0 +1,8 @@
+# $FreeBSD$
+
+test:
+	prove -vmw regress.t
+
+clean:
+	rm -rf ustar-pathnames-[12]
+	rm -f ustar.ok ustar.fail*
diff --git a/tools/regression/bin/pax/regress.t b/tools/regression/bin/pax/regress.t
new file mode 100755
index 0000000..7c392cb
--- /dev/null
+++ b/tools/regression/bin/pax/regress.t
@@ -0,0 +1,91 @@
+#! /usr/bin/perl
+#
+# $FreeBSD$
+
+use strict;
+use warnings;
+
+use Test::More tests => 6;
+use File::Path qw(rmtree mkpath);
+use Cwd;
+
+my $n = 0;
+sub create_file {
+    my $fn = shift;
+
+    $n++;
+    (my $dir = $fn) =~ s,/[^/]+$,,;
+    mkpath $dir;
+    open my $fd, ">", $fn or die "$fn: $!";
+    print $fd "file $n\n";
+}
+
+
+ustar_pathnames: { SKIP: {
+    # Prove that pax breaks up ustar pathnames properly
+
+    my $top = getcwd . "/ustar-pathnames-1";
+    skip "Current path is too long", 6 if length $top > 92;
+    rmtree $top;
+    my $subdir = "x" . "x" x (92 - length $top);
+    my $work94 = "$top/$subdir";
+    mkpath $work94;		# $work is 94 characters long
+
+    my $x49 = "x" x 49;
+    my $x50 = "x" x 50;
+    my $x60 = "x" x 60;
+    my $x95 = "x" x 95;
+
+    my @paths = (
+	"$work94/x099",		# 99 chars
+	"$work94/xx100",		# 100 chars
+	"$work94/xxx101",		# 101 chars
+	"$work94/$x49/${x50}x199",	# 199 chars
+	"$work94/$x49/${x50}xx200",	# 200 chars
+	"$work94/$x49/${x50}xxx201",	# 201 chars
+	"$work94/$x60/${x95}254",	# 254 chars
+	"$work94/$x60/${x95}x255",	# 255 chars
+    );
+
+    my @l = map { length } @paths;
+
+    my $n = 0;
+    create_file $_ for @paths;
+    system "pax -wf ustar.ok $work94";
+    ok($? == 0, "Wrote 'ustar.ok' containing files with lengths @l");
+
+    (my $orig = $top) =~ s,1$,2,;
+    rmtree $orig;
+    rename $top, $orig;
+
+    system "pax -rf ustar.ok";
+    ok($? == 0, "Restored 'ustar.ok' containing files with lengths @l");
+
+    system "diff -ru $orig $top";
+    ok($? == 0, "Restored files are identical");
+
+    rmtree $top;
+    rename $orig, $top;
+
+    # 256 chars (with components < 100 chars) should not work
+    push @paths, "$work94/x$x60/${x95}x256";	# 256 chars
+    push @l, length $paths[-1];
+    create_file $paths[-1];
+    system "pax -wf ustar.fail1 $work94";
+    ok($?, "Failed to write 'ustar.fail1' containing files with lengths @l");
+
+    # Components with 100 chars shouldn't work
+    unlink $paths[-1];
+    $paths[-1] = "$work94/${x95}xc100";		# 100 char filename
+    $l[-1] = length $paths[-1];
+    create_file $paths[-1];
+    system "pax -wf ustar.fail2 $work94";
+    ok($?, "Failed to write 'ustar.fail2' with a 100 char filename");
+
+    unlink $paths[-1];
+    $paths[-1] = "$work94/${x95}xc100/x";	# 100 char component
+    $l[-1] = length $paths[-1];
+    create_file $paths[-1];
+    system "pax -wf ustar.fail3 $work94";
+    ok($?, "Failed to write 'ustar.fail3' with a 100 char component");
+}}