path: root/TODO

TODO list for libguestfs
======================================================================

This list contains random ideas and musings on features we could add
to libguestfs in future.

   - RWMJ

Python bindings
---------------

Ideas for the Python bindings:
https://www.redhat.com/archives/fedora-virt/2009-April/msg00114.html

FTP server or FUSE?
-------------------

Originally we had intended to implement an NFS server inside the
appliance, which would allow the guest filesystems to be mounted on
the host, and large changes to be made.  We eventually rejected the
idea of using NFS, partly because it requires root to mount
filesystems in the host, and partly because of problems handling UID
mappings between host and guest filesystem.

Then we look at implementing an FTP server instead.  FTP clients are
widely available for many languages, don't require root, and don't
have any UID mapping problems.  However there is the problem of
getting the TCP connection into the guest, and that FTP requires a
secondary data connection either in or out of the guest (the NFS
situation is even more dire).

Thirdly we looked at implementing a FUSE-based filesystem.  This is
plausible - it could be implemented just by adding the additional FUSE
operations to the standard guestfs(3) API, and then implementing a
simple FUSE daemon.  (The FUSE website has some very helpful
documentation and examples).  I [RWMJ] am not particularly convinced
that a FUSE-based filesystem would really be useful to anyone, but am
prepared to accept patches if someone does all the work.

See also the mountlo project:
http://sourceforge.net/project/showfiles.php?group_id=121684&package_id=150116

BufferIn
--------

BufferIn should turn into <char *, int> and simple strings in other
languages that can handle 8 bit clean strings.

Limit on transfers would still be 2MB for these types.
 - then implement write-file properly

febootstrap / debootstrap inside appliance
------------------------------------------

This was originally proposed as a way to install new operating systems
in the appliance.  However no one has come up with a workable
solution.

Haskell bindings
----------------

Complete the Haskell bindings (see discussion on haskell-cafe).

Complete bind tests
-------------------

Complete the bind tests - must test the return values and error cases.

virt-inspector - make libvirt XML
---------------------------------

It should be possible to generate libvirt XML from virt-inspector
data, at least partially.  This would be just another output type so:

 virt-inspector --libvirt guest.img

Note that recent versions of libvirt/virt-install allow guests to be
imported, so this is not so useful any more.

"Standalone/local mode"
-----------------------

Instead of running guestfsd (the daemon) inside qemu, there should be
an option to just run guestfsd directly.

The architecture in this mode would look like:

     +------------------+
     | main program     |
     |------------------|
     | libguestfs       |
     +--------^---------+
          |   | reply
      cmd |   |
     +----v-------------+
     | guestfsd         |
     +------------------+

Notes:

(1) This only makes sense if we are running as root.

(2) There is no console / kernel messages in this configuration, but
we might consider capturing stderr from the daemon.

(3) guestfs_config and guestfs_add_drive become no-ops.

Obviously in this configuration, commands are run directly on the
local machine's disks.  You could just run the commands themselves
directly, but libguestfs provides a convenient API and language
bindings.  Also deals with tricky stuff like parsing the output of the
LVM commands.  Also we get to leverage other code such as
virt-inspector.

This is mainly useful from live CDs, ie. virt-p2v.

Should we bother having the daemon at all and just link the guestfsd
code directly into libguestfs?

PPC problems
------------

[This section should be filed as bugs, but no one seems to care for
PPC hosts and the hardware is rapidly becoming obsolete]

  ppc (32 bit) works with qemu from git, however there is no serial console

  ppc64 requires extra parameters:
    -M mac99 -cpu ppc64
  however it still fails:
    invalid/unsupported opcode: 01 - 01 - 1a (06301e83) 00000000018c2738 1
    invalid bits: 00400000 for opcode: 0b - 19 - 15 (2d746572) 0000000000009230

  no serial console in ppc or ppc64 because no one can tell us what
  console=ttyXX option to use

Supermin appliance to febootstrap
---------------------------------

Supermin appliance functionality should be moved into febootstrap.

Ideas for extra commands
------------------------

  General glibc / core programs:
    chgrp
    dd (?)
    utime / utimes / futimes / futimens / l..
    more mk*temp calls
    trunc[ate??]

  ext2 properties:
    chattr
    lsattr
    badblocks
    blkid
    debugfs
    dumpe2fs
    e2image
    e2undo
    filefrag
    findfs
    logsave
    mklost+found

  SELinux:
    chcat
    restorecon
    ch???

  Oddball:
    pivot_root
    fts(3) / ftw(3)

Other initrd-* commands
-----------------------

Such as:

initrd-extract
initrd-replace

Simple editing of configuration files
-------------------------------------

Some easy non-Augeas methods to edit configuration files.
I'm thinking:

  replace /etc/file key value

which would look in /etc/file for any instances of

  key=...
  key ...
  key:...

and replace them with

  key=value
  key value
  key:value

That would solve about 50% of reconfiguration needs, and for the
rest you'd use Augeas, 'download'+'upload' or 'edit'.

RWMJ: I had a go at implementing this, but it's quite error-prone to
do this sort of editing inside the C-based daemon code.  It's far
better to do it with Augeas, or else to use an external language like
Perl.

Quick Perl scripts
------------------

Currently we can't do Perl "one-liners".  ie. The current syntax for
any short Perl one-liner would be:

  perl -MSys::Guestfs -e '$g = Sys::Guestfs->new(); $g->add_drive ("foo"); $g->launch; $g->wait_ready; $g->mount ("/dev/sda1", "/"); ....'

You can see we're well beyond a single line just getting to the point
of adding drives and mounting.

First suggestion:

 $h = create ($filename, \"/dev/sda1\" => \"/\");

 $h = create ([$file1, $file2], \"/dev/sda1\" => \"/\");

To mount read-only, add C<ro =E<gt> 1> like this:

 $h = create ($filename, \"/dev/sda1\" => \"/\", ro => 1);

which is equivalent to the following sequence of calls:

 $h = Sys::Guestfs->new ();
 $h->set_autosync (1);
 $h->add_drive_ro ($filename);
 $h->launch ();
 $h->wait_ready ();
 $h->mount_ro (\"/dev/sda1\", \"/\");

Command-line form would be:

 perl -MSys::Guestfs=:all -e '$_=create("guest.img", "/dev/sda1" => "/"); $_->cat ("/etc/fstab");'

That's not brief enough for one-liners, so we could have an extra
autogenerated module which creates a Sys::Guestfs handle singleton
(the handle is an implicit global variable as in guestfish), eg:

 perl -MSys::Guestfs::One -e 'inspect("guest.img"); cat ("/etc/fstab");'

How would editing files work?

ntfsclone
---------

Useful imaging tool:
http://man.linux-ntfs.org/ntfsclone.8.html

Standard images
---------------

Equip guestfish with some standard images that it can load
quickly, eg:

  load ext2

Maybe it's better to create these on the fly?