bug#12339: Bug: rm -fr . doesn't dir depth first deletion yet it is documented to do so.

[Jim Meyering]

Paul Eggert wrote:

> I was about to suggest the following, on GNU/Linux:
>
>   # Don't do this unless you know what you're doing!
>   rm -fr /proc/self/cwd/
>
> Except it doesn't work!  Not even if I append '.':
>
>   $ mkdir /tmp/victim
>   $ cd /tmp/victim
>   $ touch foo
>   $ rm -fr /proc/self/cwd/
>   rm: cannot remove `/proc/self/cwd': Too many levels of symbolic links
>   $ rm -fr /proc/self/cwd/.
>   rm: cannot remove directory: `/proc/self/cwd/.'
>   $ ls
>   foo
>
> Aren't these bugs, at least?

With the following patch, I see new behavior.
It's an improvement, but we're still not there:

    $ mkdir -p d/e/f; ln -s d s; rm -r s/
    rm: cannot remove 's/': Not a directory
    [Exit 1]
    $ find
    .
    ./s
    ./d

Notice how it did traverse s/ into d/, and removed d/e and d/e/f.
The only problem is that when it attempted to remove the command-line
specified "s/", unlinkat (AT_FDCWD, "s/", AT_REMOVEDIR) failed:

    unlinkat(4, "d", 0)                     = 0
    unlinkat(5, "f", AT_REMOVEDIR)          = 0
    unlinkat(4, "e", AT_REMOVEDIR)          = 0
    unlinkat(AT_FDCWD, "s/", AT_REMOVEDIR)  = -1 ENOTDIR (Not a directory)
    rm: cannot remove 's/': Not a directory
    +++ exited with 1 +++

Now, this looks like a problem with unlinkat.

Debating whether to add a test.
Just writing the above, I know the answer.  I will add a test.

==================================================================
>From 958c553a84d37bdd8669ae68bfc8c4d4c5e7d2e1 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Tue, 4 Sep 2012 14:40:11 +0200
Subject: [PATCH] rm: avoid bogus diagnostic for a slash-decorated
 symlink-to-dir

These commands would evoke an invalid diagnostic:
    $ mkdir d && ln -s d s && env rm -r s/
    rm: cannot remove 's': Too many levels of symbolic links
remove.c was stripping trailing slashes from "s/" before passing
the name to "rm".  But a trailing slash may change the semantics,
and thus should not be stripped.
* src/remove.c (rm_fts): Do not strip trailing slashes.
* tests/rm/v-slash.sh: Adapt to new expected output.
* gnulib: Update to latest, for an improved fts.c that merely
normalizes trailing slashes.
Reported by Paul Eggert in discussion of http://bugs.gnu.org/12339
---
 gnulib              | 2 +-
 src/remove.c        | 3 ---
 tests/rm/v-slash.sh | 2 +-
 3 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/gnulib b/gnulib
index 68f693f..3a9002d 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 68f693ff1db33bf24695f0f42c62e7801966fd06
+Subproject commit 3a9002d3cc63da7110f133b1040d2d2b0aad8305
diff --git a/src/remove.c b/src/remove.c
index 69faae6..847a5cc 100644
--- a/src/remove.c
+++ b/src/remove.c
@@ -433,9 +433,6 @@ rm_fts (FTS *fts, FTSENT *ent, struct rm_options const *x)
       /* Perform checks that can apply only for command-line arguments.  */
       if (ent->fts_level == FTS_ROOTLEVEL)
         {
-          if (strip_trailing_slashes (ent->fts_path))
-            ent->fts_pathlen = strlen (ent->fts_path);
-
           /* If the basename of a command line argument is "." or "..",
              diagnose it and do nothing more with that argument.  */
           if (dot_or_dotdot (last_component (ent->fts_accpath)))
diff --git a/tests/rm/v-slash.sh b/tests/rm/v-slash.sh
index 504f4ff..ec77bd0 100755
--- a/tests/rm/v-slash.sh
+++ b/tests/rm/v-slash.sh
@@ -26,7 +26,7 @@ touch a/x || framework_failure_
 rm --verbose -r a/// > out || fail=1
 cat <<\EOF > exp || fail=1
 removed 'a/x'
-removed directory: 'a'
+removed directory: 'a/'
 EOF

 compare exp out || fail=1
--
1.7.12.176.g3fc0e4c