1 files changed, 68 insertions, 0 deletions
diff --git a/tests/misc/readlink-fp-loop.sh b/tests/misc/readlink-fp-loop.sh
new file mode 100755
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--- /dev/null
+++ b/tests/misc/readlink-fp-loop.sh
@@ -0,0 +1,68 @@
+#!/bin/sh
+# readlink from 6.9 would fail with a false-positive symlink loop error
+
+# Copyright (C) 2007-2020 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ readlink pwd
+cwd=$(env pwd -P)
+
+# To trigger this bug, we have to construct a name/situation during
+# the resolution of which the code dereferences the same symlink (S)
+# two different times with no actual loop.  In addition, arrange
+# so that the second and fourth calls to readlink operate on S.
+
+ln -s s p        || framework_failure_
+ln -s d s        || framework_failure_
+mkdir d          || framework_failure_
+echo 2 > d/2     || framework_failure_
+ln -s ../s/2 d/1 || framework_failure_
+
+# With coreutils-6.9, this would fail with ELOOP.
+readlink -v -e p/1 > out || fail=1
+# readlink -e d/2 > exp || fail=1
+echo "$cwd/d/2" > exp || framework_failure_
+compare exp out || fail=1
+
+# Construct a real loop and make sure readlink still detects it.
+ln -sf ../s/1 d/2 || framework_failure_
+readlink -v -e p/1 2> out && fail=1
+readlink_msg=$(cat out)
+case $readlink_msg in
+  "readlink: p/1: "*) ;;
+  *) fail=1;;
+esac
+symlink_loop_msg=${readlink_msg#"readlink: p/1: "}
+
+# Exercise the hash table code.
+ln -nsf ../s/3 d/2 || framework_failure_
+ln -nsf ../p/4 d/3 || framework_failure_
+ln -nsf ../p/5 d/4 || framework_failure_
+ln -nsf ../p/6 d/5 || framework_failure_
+ln -nsf ../p/7 d/6 || framework_failure_
+ln -nsf ../p/8 d/7 || framework_failure_
+echo x > d/8       || framework_failure_
+readlink -v -e p/1 > out || fail=1
+echo "$cwd/d/8" > exp || framework_failure_
+compare exp out || fail=1
+
+# A trivial loop
+ln -s loop loop
+readlink -v -e loop 2> out && fail=1
+echo "readlink: loop: $symlink_loop_msg" > exp || framework_failure_
+compare exp out || fail=1
+
+Exit $fail