[lxc-devel] [PATCH 0/2 v4] Update absolute paths for overlay and aufs mounts

[Christian Brauner]

Changes v4:
(1) When searching for substrings with strstr() also check for q >= lend to
    ensure that we limit our search to the current line.

+       if ((!(q = strstr(p, " overlay")) || q >= lend) && (!(q = strstr(p, " aufs")) || q >= lend))
+               goto next;
+	if (!(q = strstr(p, olddir)) || (q >= lend))
+               goto next;

(2) Simplify clone_update_unexp_ovl_paths() by using gotos.
(3) Fix indentation in update_ovl_paths().
(4) Replace old_work also when old_upper is not present:

        if (tmp_mnt_entry)
                new_mnt_entry = lxc_string_replace(old_work, new_work, tmp_mnt_entry);
+	else
+	        new_mnt_entry = lxc_string_replace(old_work, new_work, mnt_entry);

Changes v3:
(1) Better names for functions: update_union_mount_entry_paths() becomes
    update_ovl_paths() and clone_update_unexp_ovl_dir() becomes
    clone_update_unexp_ovl_paths().
(2) Use the stricter check

                if (p >= lend)
                        continue;

   in clone_update_unexp_ovl_paths().

(3) Insert comment into update_ovl_paths() that lxc_conf->unexpanded_config
    needs to be updated separately from lxc_conf->mount_list.

Changes v2:
(1) Fix calculations in update_unexp_ovl_dir(). (The function was modelled after
    update_unexp_hooks() and I'm pretty sure that things are wrong there too and
    need a thorough check but I'm in the Alps for the weekend so this will have
    to wait...)
    Most noticeably the calculation when olddirlen >= newdirlen becomes:

                memmove(q + newdirlen, q + newdirlen + diff,
                        strlen(q) - newdirlen - diff + 1);

    and int the else-branch it becomes:

                memmove(new + poffset + newdirlen,
                        new + poffset + olddirlen,
                        oldlen - poffset - olddirlen + 1);

    The call to realloc() becomes:

                new = realloc(conf->unexpanded_config, newlen + 1);

    and we *need* to set:

                conf->unexpanded_alloced = newlen + 1;

Changes:
(1) Make updating lxc_conf->mnt_list and lxc_conf->unexpanded_config independent
    of each other so that users can include overlay mounts from other files.
(2) Update lxc_conf->unexpanded_config by using a separate function
    clone_update_unexp_ovl_dir() in confile.c.
(3) Move various temporary variables inside the lxc_list_for_each(iterator,
    &lxc_conf->mount_list) {*/ do stuff */} per Serge's request.
(4) Use uniform exit strategy when the function fails or succeeds.

Christian Brauner (3):
  Add clone_update_unexp_ovl_paths() function
  Update absolute paths for overlay and aufs mounts
  Fix wrong calculations in clone_update_unexp_hooks()

 src/lxc/confile.c      | 126 ++++++++++++++++++++++++++++++++++++++++++++-----
 src/lxc/confile.h      |   3 ++
 src/lxc/lxccontainer.c | 100 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 216 insertions(+), 13 deletions(-)

-- 
2.6.2