(Will push in a bit barring any objections)

lvm, btrfs, and zfs snapshots each do an ok job of handling deletions
for us - a btrfs snapshot does fine after the original is removed,
while zfs and lvm will both refuse to allow the original to be deleted
while the snapshot exists.

Overlayfs doesn't do this for us.  So, for overlayfs snapshots, track
the dependencies.

When c2 is created as an overlayfs snapshot of dir-backed c1, then

1. c2's lxc_rdepends file will contain

	c1_lxcpath
	c1_lxcname

2. c1's lxc_snapshots will contain "1"

c1 cannot be deleted so long as lxc_snapshots exists and contains
a non-zero number.

The contents of lxc_snapshots and lxc_rdepends are protected by
container_disk_lock() and at lxc_clone by the new container not yet
being accessible.

(Originally I was going to keep them in the container config, but the
problem with using $lxcpath/$name/config is that api users could end up
calling c->save_config() with a cached old value of snapshots/rdepends.)

Changelog:
	aug 21: check for fprintf and fclose failures
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Dwight Engen <dwight.engen@oracle.com>

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

This should also fix a memory leak, since we were freeing it under ifdef
but always allocating it.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

the previous 'patch_start' can be vastly simplified now that I better
understand what the bug was.  Instead of wrapping 'start', we only
need to ensure that /etc/init exists inside the overlayfs, so that the
directory that upstart watches is guaranteed to be in the overlay, not
the underlay.

The problem is described under bug 1213925.
Signed-off-by: Scott Moser <smoser@ubuntu.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

1. add cgroup_get_subsys_abspath() which returns the absolute
path for a subsystem mount, and use that where needed to actually
set cgroup values

2. cgroup_devices_has_{allow,deny}: don't mix int and boolean
values.  Also, accept 'a *:* rwm" as any whitelist entry for
has_allow().

3. subsys_lists_match(): fix an off-by-one error in calculating
updated oldlen.  (we need to keep the extra char for '\0')

4. return -1, not 0, if lxc_cgroup_attach fails to open
/proc/self/cgroup.
Signed-off-by: Ubuntu <ubuntu@ip-10-181-158-15.ec2.internal>

Adds the arch_to_personality function that looks up an architecture
and returns the corresponding personality. This may be used in
conjunction with the attach/attach_wait keyword argument.
Signed-off-by: Christian Seiler <christian@iwakd.de>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Christian Seiler <christian@iwakd.de>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

This fixes some minor bugs in the cgroup logic that made start and
attach fail (at least when all cgroup controllers were mounted
together).
Signed-off-by: Christian Seiler <christian@iwakd.de>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Christian Seiler <christian@iwakd.de>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Christian Seiler <christian@iwakd.de>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>

This adds a couple of missing includes, uses the local version of
getline on bionic and replaces getpwuid_r by getpwuid.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

We use confstr to grab the default PATH value. If it's not there, just
use a standard one with bin and sbin for /, /usr and /usr/local.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

initstate/random doesn't work on bionic, srand/rand works on everything,
so let's use that.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

The current Android NDK provides a clone() defintion that's identical to
eglibc's so we can drop the ifdef from that one.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Those two aren't always around (specifically on bionic), so add some
defines in case they aren't already defined.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

New code now uses getmntent_r so we need it exported so that it can be
used when building on bionic.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

The two functions are identical but strrchr also works on Bionic.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

This adds a local ifaddrs implementation to be used on Bionic or other C
libraries that don't come with a getifaddrs implementation.

This code was written by Kenneth MacKay and is under a two-clause BSD
license (copyright information in the file headers).
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

upstart depends on inotify, and overlayfs does not support inotify.

That means that the following results in 'tgt' not running. tgt is simply
used here as an example of a service that installs an upstart job and
starts it on package install.
 lxc-clone -s -B overlayfs -o source-precise-amd64 -n test1
 lxc-start -n test1
 ..
 apt-get install tgt

The change here is to modify /sbin/start inside the container so that when
something explicitly tries 'start', it results in an explicit call to
'initctl reload-configuration' so that upstart is aware of the newly
placed job.

Should overlayfs ever gain inotify support, this should still not cause
any harm.
Signed-off-by: Scott Moser <smoser@ubuntu.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

If you go to the trouble to request a -s (snapshot) clone of
a container which is dir backingstore, then you deserve an
overlayfs clone.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Because they are in probing functions.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

strdup and strndup still don't exist on bionic, so we need to do the
alloc() call ourselves or free the memory by hand.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Without this, make dist doesn't include it and LXC fails to build.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>