Subject: bug#44889: [PATCH] rm: do not skip extra files when removal of empty directories fails

From: Nick Alcock <[email-masked]>
Date: Thu, 26 Nov 2020 14:35:17 +0000

From: Nishant Nayan <[email-masked]>

When removing a directory fails for some reason, and that directory
is empty, the rm_fts code gets the return value of the excise call
confused with the return value of its earlier call to prompt,
causing fts_skip_tree to be called repeatedly and the next file
that rm would otherwise have deleted to survive.

[nca: added commit log, test]

* src/remove.c (rm_fts): Only ever carry out one branch of the
rm -i failure path for directories, never both (a user cannot both
answer y and n to an rm -i prompt).
* tests/rm/empty-immutable-skip.sh: New root-only test.
* tests/local.mk: Add it.
* NEWS: Mention the bug fix.
---
 NEWS                             |  3 +++
 src/remove.c                     |  3 +--
 tests/local.mk                   |  1 +
 tests/rm/empty-immutable-skip.sh | 46 ++++++++++++++++++++++++++++++++
 4 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100755 tests/rm/empty-immutable-skip.sh

diff --git a/NEWS b/NEWS
index 61b5d42f6..ce40fc4ff 100644
--- a/NEWS
+++ b/NEWS
@@ -24,6 +24,9 @@ GNU coreutils NEWS                                    -*- outline -*-
   invalid combinations of case character classes.
   [bug introduced in coreutils-8.6]
 
+  rm no longer skips an extra file when the removal of an empty directory fails.
+  [introduced by the rewrite to make rm use fts in coreutils-8.0]
+
 ** Changes in behavior
 
   cp and install now default to copy-on-write (COW) if available.
diff --git a/src/remove.c b/src/remove.c
index 2d40c55cd..1150cf179 100644
--- a/src/remove.c
+++ b/src/remove.c
@@ -508,8 +508,7 @@ rm_fts (FTS *fts, FTSENT *ent, struct rm_options const *x)
             s = excise (fts, ent, x, true);
             fts_skip_tree (fts, ent);
           }
-
-        if (s != RM_OK)
+        else if (s != RM_OK)
           {
             mark_ancestor_dirs (ent);
             fts_skip_tree (fts, ent);
diff --git a/tests/local.mk b/tests/local.mk
index e1c4675c2..297760cc5 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -136,6 +136,7 @@ all_root_tests =				\
   tests/rm/no-give-up.sh			\
   tests/rm/one-file-system.sh			\
   tests/rm/read-only.sh				\
+  tests/rm/empty-immutable-skip.sh		\
   tests/tail-2/append-only.sh			\
   tests/tail-2/end-of-device.sh			\
   tests/touch/now-owned-by-other.sh
diff --git a/tests/rm/empty-immutable-skip.sh b/tests/rm/empty-immutable-skip.sh
new file mode 100755
index 000000000..e31417073
--- /dev/null
+++ b/tests/rm/empty-immutable-skip.sh
@@ -0,0 +1,46 @@
+#!/bin/sh
+# Ensure that rm does not skip extra files after hitting an empty immutable dir.
+# Requires root access to do chattr +i, as well as an ext[23] or xfs file system
+
+# Copyright (C) 2006-2020 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_ tail
+require_root_
+
+# These simple one-file operations are expected to work even in the
+# presence of this bug, and we need them to set up the rest of the test.
+chattr_i_works=1
+touch f
+chattr +i f 2>/dev/null || chattr_i_works=0
+rm f 2>/dev/null
+test -f f || chattr_i_works=0
+chattr -i f 2>/dev/null || chattr_i_works=0
+rm f 2>/dev/null || chattr_i_works=0
+test -f f && chattr_i_works=0
+
+if test $chattr_i_works = 0; then
+  skip_ "chattr +i doesn't work on this file system"
+fi
+
+mkdir empty
+touch x y
+chattr +i empty
+rm -rf empty x y
+{ test -f x || test -f y || test -f z; } && fail=1
+chattr -i empty
+
+Exit $fail
-- 
2.29.0.249.g249b51256f