src/patches/suse-2.6.27.31/patches.apparmor/d_namespace_path.diff

   1 From: Andreas Gruenbacher <agruen@suse.de>
   2 Subject: Add d_namespace_path() to compute namespace relative pathnames
   3
   4 In AppArmor, we are interested in pathnames relative to the namespace root.
   5 This is the same as d_path() except for the root where the search ends. Add
   6 a function for computing the namespace-relative path.
   7
   8 Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
   9 Signed-off-by: John Johansen <jjohansen@suse.de>
  10
  11 ---
  12  fs/namespace.c        |   30 ++++++++++++++++++++++++++++++
  13  include/linux/mount.h |    2 ++
  14  2 files changed, 32 insertions(+)
  15
  16 --- a/fs/namespace.c
  17 +++ b/fs/namespace.c
  18 @@ -2357,3 +2357,33 @@ void put_mnt_ns(struct mnt_namespace *ns
  19         kfree(ns);
  20  }
  21  EXPORT_SYMBOL(put_mnt_ns);
  22 +
  23 +char *d_namespace_path(struct dentry *dentry, struct vfsmount *vfsmnt,
  24 +                      char *buf, int buflen)
  25 +{
  26 +       struct path root, tmp, ns_root = { };
  27 +       struct path path = { .mnt = vfsmnt, .dentry = dentry };
  28 +       char *res;
  29 +
  30 +       read_lock(&current->fs->lock);
  31 +       root = current->fs->root;
  32 +       path_get(&current->fs->root);
  33 +       read_unlock(&current->fs->lock);
  34 +       spin_lock(&vfsmount_lock);
  35 +       if (root.mnt)
  36 +               ns_root.mnt = mntget(root.mnt->mnt_ns->root);
  37 +       if (ns_root.mnt)
  38 +               ns_root.dentry = dget(ns_root.mnt->mnt_root);
  39 +       spin_unlock(&vfsmount_lock);
  40 +       tmp = ns_root;
  41 +       res = __d_path(&path, &tmp, buf, buflen,
  42 +                      D_PATH_FAIL_DELETED | D_PATH_DISCONNECT);
  43 +       path_put(&root);
  44 +       path_put(&ns_root);
  45 +
  46 +       /* Prevent empty path for lazily unmounted filesystems. */
  47 +       if (!IS_ERR(res) && *res == '\0')
  48 +               *--res = '.';
  49 +       return res;
  50 +}
  51 +EXPORT_SYMBOL(d_namespace_path);
  52 --- a/include/linux/mount.h
  53 +++ b/include/linux/mount.h
  54 @@ -137,4 +137,6 @@ extern void mark_mounts_for_expiry(struc
  55  extern spinlock_t vfsmount_lock;
  56  extern dev_t name_to_dev_t(char *name);
  57
  58 +extern char *d_namespace_path(struct dentry *, struct vfsmount *, char *, int);
  59 +
  60  #endif /* _LINUX_MOUNT_H */