From 58034aa68fd45ba3ff8bbb554d2cdef6ac31de17 Mon Sep 17 00:00:00 2001
From: Ondrej Oprala <ooprala@redhat.com>
Date: Wed, 8 Aug 2012 15:24:05 +0200
Subject: [PATCH] du: Fix an issue with bogus warnings on bind-mounted
 directories

* NEWS: Mention the fix.
* src/du.c: Add a function to read+stat mount points
and properly check cyclic directory entries.
---
 NEWS     |  3 +++
 gnulib   |  2 +-
 src/du.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/NEWS b/NEWS
index ca4568a..8f85c2b 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,9 @@ GNU coreutils NEWS                                    -*- outline -*-
 
 ** Bug fixes
 
+  du no longer emits bogus warnings when traversing bind-mounted
+  directory cycles.
+
   cksum now prints checksums atomically so that concurrent
   processes will not intersperse their output.
   [the bug dates back to the initial implementation]
diff --git a/gnulib b/gnulib
index 39cedf6..696aa74 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 39cedf6f427350ac47118d231c05a7b73b609f89
+Subproject commit 696aa74b38f8c109c21e4c01194faab53fb4cefc
diff --git a/src/du.c b/src/du.c
index 7333941..b915320 100644
--- a/src/du.c
+++ b/src/du.c
@@ -27,6 +27,7 @@
 #include <getopt.h>
 #include <sys/types.h>
 #include <assert.h>
+#include <mntent.h>
 #include "system.h"
 #include "argmatch.h"
 #include "argv-iter.h"
@@ -60,9 +61,14 @@ extern bool fts_debug;
 # define FTS_CROSS_CHECK(Fts)
 #endif
 
+#define MTAB "/etc/mtab"
+
 /* A set of dev/ino pairs.  */
 static struct di_set *di_set;
 
+/* A hash table for mount points. */
+static struct di_set *di_mnt;
+
 /* Keep track of the preceding "level" (depth in hierarchy)
    from one call of process_file to the next.  */
 static size_t prev_level;
@@ -333,11 +339,11 @@ Mandatory arguments to long options are mandatory for short options too.\n\
   exit (status);
 }
 
-/* Try to insert the INO/DEV pair into the global table, HTAB.
+/* Try to insert the INO/DEV pair into the di_set table.
    Return true if the pair is successfully inserted,
    false if the pair is already in the table.  */
 static bool
-hash_ins (ino_t ino, dev_t dev)
+hash_ins (struct di_set *di_set, ino_t ino, dev_t dev)
 {
   int inserted = di_set_insert (di_set, dev, ino);
   if (inserted < 0)
@@ -461,7 +467,7 @@ process_file (FTS *fts, FTSENT *ent)
       if (excluded
           || (! opt_count_all
               && (hash_all || (! S_ISDIR (sb->st_mode) && 1 < sb->st_nlink))
-              && ! hash_ins (sb->st_ino, sb->st_dev)))
+              && ! hash_ins (di_set, sb->st_ino, sb->st_dev)))
         {
           /* If ignoring a directory in preorder, skip its children.
              Ignore the next fts_read output too, as it's a postorder
@@ -476,6 +482,17 @@ process_file (FTS *fts, FTSENT *ent)
           return true;
         }
 
+      /*Check if dir is already in the mount table */
+      if (S_ISDIR (sb->st_mode))
+        {
+          if (di_set_lookup (di_mnt, sb->st_dev, sb->st_ino))
+            {
+              fts_set (fts, ent, FTS_SKIP);
+              error (0, 0, _("mount point %s already traversed"), quote (file));
+              return false;
+            }
+        }
+
       switch (info)
         {
         case FTS_D:
@@ -623,6 +640,29 @@ du_files (char **files, int bit_flags)
   return ok;
 }
 
+/* Fill the di_mnt table with dev/ino pairs
+ * of mount points  */
+
+static void
+fill_mount_table (void)
+{
+  FILE *mtab_fp;
+  struct mntent *mnt_ent;
+  struct stat *buf;
+  buf = xmalloc (sizeof *buf);
+
+  mtab_fp = setmntent (MTAB, "r");
+
+  while (mnt_ent = getmntent (mtab_fp))
+    {
+      if (!stat (mnt_ent->mnt_dir, buf))
+        hash_ins (di_mnt, buf->st_ino, buf->st_dev);
+    }
+
+  free (buf);
+  endmntent (mtab_fp);
+}
+
 int
 main (int argc, char **argv)
 {
@@ -922,6 +962,13 @@ main (int argc, char **argv)
     xalloc_die ();
 
   /* Initialize the set of dev,inode pairs.  */
+
+  di_mnt = di_set_alloc ();
+  if (!di_mnt)
+    xalloc_die ();
+
+  fill_mount_table ();
+
   di_set = di_set_alloc ();
   if (!di_set)
     xalloc_die ();
@@ -1002,6 +1049,7 @@ main (int argc, char **argv)
 
   argv_iter_free (ai);
   di_set_free (di_set);
+  di_set_free (di_mnt);
 
   if (files_from && (ferror (stdin) || fclose (stdin) != 0) && ok)
     error (EXIT_FAILURE, 0, _("error reading %s"), quote (files_from));
-- 
1.7.11.2