stat: add %m to output the mount point for a file

* src/find-mount-point.c: A new file refactoring
find_mount_point() out from df.c
* src/find-mount-point.h: Likewise.
* src/df.c: Use the new find-mount-point module.
* src/stat.c (print_stat): Handle the new %m format.
(find_bind_mount): A new function to
return the bind mount for a file if any.
(out_mount_mount): Print the bind mount for a file, or else
the standard mount point given by the find-mount-point module.
(usage): Document the %m format directive.
* src/Makefile.am: Reference the refactored find-mount-point.c
* po/POTFILES.in: Add find_mount_point.c to the translation list
* doc/coreutils.texi (stat invocation): Document %m,
and how it may differ from the mount point that df outputs.
* test/misc/stat-mount: A new test to correlate mount points
output from df and stat.
* tests/Makefile.am: Reference the new test.
* NEWS: Mention the new feature
* THANKS: Add the author

Signed-off-by: Pádraig Brady <P@draigBrady.com>

2 files changed, 32 insertions, 0 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 4aa93bf9e..5619d0b76 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -241,6 +241,7 @@ TESTS =						\
   misc/split-l					\
   misc/stat-fmt					\
   misc/stat-hyphen				\
+  misc/stat-mount				\
   misc/stat-printf				\
   misc/stat-slash				\
   misc/stdbuf					\
diff --git a/tests/misc/stat-mount b/tests/misc/stat-mount
new file mode 100755
index 000000000..c1c43d49c
--- /dev/null
+++ b/tests/misc/stat-mount
@@ -0,0 +1,31 @@
+#!/bin/sh
+# Test stat -c%m
+
+# Copyright (C) 2010 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 <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+
+# Note we assume that the current directory is not bind mounted
+# (as then, stat and df may have different results).
+# This should be the case given the directory is temporary
+# for the duration of the test.
+
+df_mnt=$(df -P . | sed -n '2s/.* \([^ ]*$\)/\1/p')
+stat_mnt=$(stat -c%m .)
+
+test "$df_mnt" = "$stat_mnt" || fail=1
+
+Exit $fail