Subject: Re: bug#6555: stat enhancement

From: Pádraig Brady <[email-masked]>
Date: Thu, 19 Aug 2010 00:45:37 +0100

On 13/08/10 04:01, A Burgie wrote:
> I have received confirmation of the completion of my exciting
> paperwork.  I can send the PDF for proof but at this point all of the
> legal stuff should be handled.

I updated the patch further, adding a test,
and fixing a small mem leak in print_stat().
However I'm wary about pushing as I'm worried
about bypassing most of the logic from df::show_point().
I.E. do we lose anything by not using read_file_system_list()?

cheers,
Pádraig.
>From 8f61cca9325d54fbc7ef30d23394d0f3a536dd1f Mon Sep 17 00:00:00 2001
From: Aaron Burgemeister <[email-masked]>
Date: Thu, 15 Jul 2010 19:54:49 -0600
Subject: [PATCH] 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): Using the new module,
output the mount point for the new %m format directive.
(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
* 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
---
 NEWS                   |    3 +
 THANKS                 |    1 +
 doc/coreutils.texi     |    1 +
 po/POTFILES.in         |    1 +
 src/Makefile.am        |    4 ++
 src/df.c               |   91 +--------------------------------------
 src/find-mount-point.c |  113 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/find-mount-point.h |   17 +++++++
 src/stat.c             |   13 ++++++
 tests/Makefile.am      |    1 +
 tests/misc/stat-mount  |   27 +++++++++++
 11 files changed, 182 insertions(+), 90 deletions(-)
 create mode 100644 src/find-mount-point.c
 create mode 100644 src/find-mount-point.h
 create mode 100755 tests/misc/stat-mount

diff --git a/NEWS b/NEWS
index ae7b839..bece07b 100644
--- a/NEWS
+++ b/NEWS
@@ -24,6 +24,9 @@ GNU coreutils NEWS                                    -*- outline -*-
 
   sort now supports -d, -f, -i, -R, and -V in any combination.
 
+  stat now accepts the %m format directive to output
+  the mount point for a file.
+
 ** Changes in behavior
 
   du now uses less than half as much memory when operating on trees
diff --git a/THANKS b/THANKS
index 34b95f1..c368a2c 100644
--- a/THANKS
+++ b/THANKS
@@ -8,6 +8,7 @@ the bug-report mailing list (as seen on last line of e.g., cp --help).
 
 ???                                 [email-masked]
 A Costa                             [email-masked]
+Aaron Burgemeister                  [email-masked]
 Aaron Hawley                        [email-masked]
 Achim Blumensath                    [email-masked]
 Adam Jimerson                       [email-masked]
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 7eedec7..1453f30 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -10685,6 +10685,7 @@ The valid @var{format} directives for files with @option{--format} and
 @item %G - Group name of owner
 @item %h - Number of hard links
 @item %i - Inode number
+@item %m - Mount point
 @item %n - File name
 @item %N - Quoted file name with dereference if symbolic link
 @item %o - I/O block size
diff --git a/po/POTFILES.in b/po/POTFILES.in
index be20f4c..673a7d9 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -61,6 +61,7 @@ src/expand.c
 src/expr.c
 src/factor.c
 src/false.c
+src/find-mount-point.c
 src/fmt.c
 src/fold.c
 src/getlimits.c
diff --git a/src/Makefile.am b/src/Makefile.am
index 1a19fa6..00c7ff7 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -145,6 +145,7 @@ noinst_HEADERS =	\
   copy.h		\
   cp-hash.h		\
   dircolors.h		\
+  find-mount-point.h	\
   fs.h			\
   group-list.h		\
   ls.h			\
@@ -478,6 +479,9 @@ rm_SOURCES = rm.c remove.c
 mkdir_SOURCES = mkdir.c prog-fprintf.c
 rmdir_SOURCES = rmdir.c prog-fprintf.c
 
+df_SOURCES = df.c find-mount-point.c
+stat_SOURCES = stat.c find-mount-point.c
+
 uname_SOURCES = uname.c uname-uname.c
 arch_SOURCES = uname.c uname-arch.c
 nproc_SOURCES = nproc.c
diff --git a/src/df.c b/src/df.c
index 76622fb..97b1637 100644
--- a/src/df.c
+++ b/src/df.c
@@ -29,8 +29,7 @@
 #include "human.h"
 #include "mountlist.h"
 #include "quote.h"
-#include "save-cwd.h"
-#include "xgetcwd.h"
+#include "find-mount-point.h"
 
 /* The official name of this program (e.g., no `g' prefix).  */
 #define PROGRAM_NAME "df"
@@ -522,94 +521,6 @@ show_dev (char const *disk, char const *mount_point,
   putchar ('\n');
 }
 
-/* Return the root mountpoint of the file system on which FILE exists, in
-   malloced storage.  FILE_STAT should be the result of stating FILE.
-   Give a diagnostic and return NULL if unable to determine the mount point.
-   Exit if unable to restore current working directory.  */
-static char *
-find_mount_point (const char *file, const struct stat *file_stat)
-{
-  struct saved_cwd cwd;
-  struct stat last_stat;
-  char *mp = NULL;		/* The malloced mount point.  */
-
-  if (save_cwd (&cwd) != 0)
-    {
-      error (0, errno, _("cannot get current directory"));
-      return NULL;
-    }
-
-  if (S_ISDIR (file_stat->st_mode))
-    /* FILE is a directory, so just chdir there directly.  */
-    {
-      last_stat = *file_stat;
-      if (chdir (file) < 0)
-        {
-          error (0, errno, _("cannot change to directory %s"), quote (file));
-          return NULL;
-        }
-    }
-  else
-    /* FILE is some other kind of file; use its directory.  */
-    {
-      char *xdir = dir_name (file);
-      char *dir;
-      ASSIGN_STRDUPA (dir, xdir);
-      free (xdir);
-
-      if (chdir (dir) < 0)
-        {
-          error (0, errno, _("cannot change to directory %s"), quote (dir));
-          return NULL;
-        }
-
-      if (stat (".", &last_stat) < 0)
-        {
-          error (0, errno, _("cannot stat current directory (now %s)"),
-                 quote (dir));
-          goto done;
-        }
-    }
-
-  /* Now walk up FILE's parents until we find another file system or /,
-     chdiring as we go.  LAST_STAT holds stat information for the last place
-     we visited.  */
-  while (true)
-    {
-      struct stat st;
-      if (stat ("..", &st) < 0)
-        {
-          error (0, errno, _("cannot stat %s"), quote (".."));
-          goto done;
-        }
-      if (st.st_dev != last_stat.st_dev || st.st_ino == last_stat.st_ino)
-        /* cwd is the mount point.  */
-        break;
-      if (chdir ("..") < 0)
-        {
-          error (0, errno, _("cannot change to directory %s"), quote (".."));
-          goto done;
-        }
-      last_stat = st;
-    }
-
-  /* Finally reached a mount point, see what it's called.  */
-  mp = xgetcwd ();
-
-done:
-  /* Restore the original cwd.  */
-  {
-    int save_errno = errno;
-    if (restore_cwd (&cwd) != 0)
-      error (EXIT_FAILURE, errno,
-             _("failed to return to initial working directory"));
-    free_cwd (&cwd);
-    errno = save_errno;
-  }
-
-  return mp;
-}
-
 /* If DISK corresponds to a mount point, show its usage
    and return true.  Otherwise, return false.  */
 static bool
diff --git a/src/find-mount-point.c b/src/find-mount-point.c
new file mode 100644
index 0000000..f3a2074
--- /dev/null
+++ b/src/find-mount-point.c
@@ -0,0 +1,113 @@
+/* find-mount-point.c -- find the root mount point for a file.
+   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/>.  */
+
+#include <config.h>
+#include <sys/types.h>
+
+#include "system.h"
+#include "error.h"
+#include "quote.h"
+#include "save-cwd.h"
+#include "xgetcwd.h"
+#include "find-mount-point.h"
+
+/* Return the root mountpoint of the file system on which FILE exists, in
+   malloced storage.  FILE_STAT should be the result of stating FILE.
+   Give a diagnostic and return NULL if unable to determine the mount point.
+   Exit if unable to restore current working directory.  */
+extern char *
+find_mount_point (const char *file, const struct stat *file_stat)
+{
+  struct saved_cwd cwd;
+  struct stat last_stat;
+  char *mp = NULL;		/* The malloced mount point.  */
+
+  if (save_cwd (&cwd) != 0)
+    {
+      error (0, errno, _("cannot get current directory"));
+      return NULL;
+    }
+
+  if (S_ISDIR (file_stat->st_mode))
+    /* FILE is a directory, so just chdir there directly.  */
+    {
+      last_stat = *file_stat;
+      if (chdir (file) < 0)
+        {
+          error (0, errno, _("cannot change to directory %s"), quote (file));
+          return NULL;
+        }
+    }
+  else
+    /* FILE is some other kind of file; use its directory.  */
+    {
+      char *xdir = dir_name (file);
+      char *dir;
+      ASSIGN_STRDUPA (dir, xdir);
+      free (xdir);
+
+      if (chdir (dir) < 0)
+        {
+          error (0, errno, _("cannot change to directory %s"), quote (dir));
+          return NULL;
+        }
+
+      if (stat (".", &last_stat) < 0)
+        {
+          error (0, errno, _("cannot stat current directory (now %s)"),
+                 quote (dir));
+          goto done;
+        }
+    }
+
+  /* Now walk up FILE's parents until we find another file system or /,
+     chdiring as we go.  LAST_STAT holds stat information for the last place
+     we visited.  */
+  while (true)
+    {
+      struct stat st;
+      if (stat ("..", &st) < 0)
+        {
+          error (0, errno, _("cannot stat %s"), quote (".."));
+          goto done;
+        }
+      if (st.st_dev != last_stat.st_dev || st.st_ino == last_stat.st_ino)
+        /* cwd is the mount point.  */
+        break;
+      if (chdir ("..") < 0)
+        {
+          error (0, errno, _("cannot change to directory %s"), quote (".."));
+          goto done;
+        }
+      last_stat = st;
+    }
+
+  /* Finally reached a mount point, see what it's called.  */
+  mp = xgetcwd ();
+
+done:
+  /* Restore the original cwd.  */
+  {
+    int save_errno = errno;
+    if (restore_cwd (&cwd) != 0)
+      error (EXIT_FAILURE, errno,
+             _("failed to return to initial working directory"));
+    free_cwd (&cwd);
+    errno = save_errno;
+  }
+
+  return mp;
+}
diff --git a/src/find-mount-point.h b/src/find-mount-point.h
new file mode 100644
index 0000000..49be9ba
--- /dev/null
+++ b/src/find-mount-point.h
@@ -0,0 +1,17 @@
+/* find-mount-point.h -- find the root mount point for a file.
+   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/>.  */
+
+extern char* find_mount_point (const char *, const struct stat *);
diff --git a/src/stat.c b/src/stat.c
index c3730f0..a75b83e 100644
--- a/src/stat.c
+++ b/src/stat.c
@@ -68,6 +68,7 @@
 #include "quotearg.h"
 #include "stat-time.h"
 #include "strftime.h"
+#include "find-mount-point.h"
 
 #if USE_STATVFS
 # define STRUCT_STATVFS struct statvfs
@@ -612,6 +613,7 @@ print_stat (char *pformat, size_t prefix_len, char m,
   struct stat *statbuf = (struct stat *) data;
   struct passwd *pw_ent;
   struct group *gw_ent;
+  char *mp;
   bool fail = false;
 
   switch (m)
@@ -679,6 +681,16 @@ print_stat (char *pformat, size_t prefix_len, char m,
     case 't':
       out_uint_x (pformat, prefix_len, major (statbuf->st_rdev));
       break;
+    case 'm':
+      mp = find_mount_point (filename, statbuf);
+      if (mp)
+        {
+          out_string (pformat, prefix_len, mp);
+          free (mp);
+        }
+      else
+        fail = true;
+      break;
     case 'T':
       out_uint_x (pformat, prefix_len, minor (statbuf->st_rdev));
       break;
@@ -1025,6 +1037,7 @@ The valid format sequences for files (without --file-system):\n\
       fputs (_("\
   %h   Number of hard links\n\
   %i   Inode number\n\
+  %m   Mount point\n\
   %n   File name\n\
   %N   Quoted file name with dereference if symbolic link\n\
   %o   I/O block size\n\
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 4aa93bf..5619d0b 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 0000000..99e29cb
--- /dev/null
+++ b/tests/misc/stat-mount
@@ -0,0 +1,27 @@
+#!/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/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+
+
+df_mnt=$(df -P . | sed -n '2s/.* \([^ ]*$\)/\1/p')
+stat_mnt=$(stat -c%m .)
+
+test "$df_mnt" = "$stat_mnt" || fail=1
+
+Exit $fail
-- 
1.6.2.5