tools: allow lxc-attach to undefined containers

cgroups: enable container without CAP_SYS_ADMIN

In case cgroup namespaces are supported but we do not have CAP_SYS_ADMIN we
need to mount cgroups for the container. This patch enables both privileged and
unprivileged containers without CAP_SYS_ADMIN.

Closes #1737.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

lxc-debian improvements

This avoids the dance of updating the list of valid releases every time
Debian makes a new release.

It also fixes the following bug: even though lxc-debian will default to
creating containers of the latest stable by querying the archive, it
won't allow you to explicitly request `stable` because the current list
of valid releases don't include it.

Last, but not least, avoid hitting the mirror in the case the desired
release is one of the ones we know will always be there, i.e. stable,
testing, sid, and unstable.
Signed-off-by: Antonio Terceiro <terceiro@debian.org>

Doing that confuses locale generation. lxc-ubuntu does the same check
Signed-off-by: Antonio Terceiro <terceiro@debian.org>

Call lxc_config_define_load from lxc_execute again

Fix typo in lxc-net script

Signed-off-by: Jordan Webb <jordemort@github.com>

Signed-off-by: adrian5 <adrian5@users.noreply.github.com>

Signed-off-by: Jordan Webb <jordemort@github.com>

For example the following sequence is expected to work:

lxc-start -n containerName -f /path/to/conf \
-s 'lxc.id_map = u 0 100000 65536' \
-s 'lxc.id_map = g 0 100000 65536' \
-s 'lxc.rootfs = /path/to/rootfs' \
-s 'lxc.init_cmd = /path/to/initcmd'

lxc-attach -n containerName

Closes #984.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

lxc-debian: allow creating `testing` and `unstable`

Being able to create `testing` containers, regardless of what's the name
of the next stable, is useful in several contexts, included but not
limited to testing purposes. i.e. one won't need to explicitly switch to
`bullseye` once `buster` is released to be able to continue tracking
`testing`. While we are at it, let's also enable `unstable`, which is
exactly the same as `sid`, but there is no reason for not being able to.
Signed-off-by: Antonio Terceiro <terceiro@debian.org>

ringbuffer: implement efficient and performant ringbuffer

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Closes #1857.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Closes #1857.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Closes #1857.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

liblxc will use a ringbuffer implementation that employs mmap()ed memory.
Specifically, the ringbuffer will create an anonymous memory mapping twice the
requested size for the ringbuffer. Afterwards, an in-memory file the requested
size for the ringbuffer will be created. This in-memory file will then be
memory mapped twice into the previously established anonymous memory mapping
thereby effectively splitting the anoymous memory mapping in two halves of
equal size.  This will allow the ringbuffer to get rid of any complex boundary
and wrap-around calculation logic. Since the underlying physical memory is the
same in both halves of the memory mapping only a single memcpy() call for both
reads and writes from and to the ringbuffer is needed.

Design Notes:
- Since we're using MAP_FIXED memory mappings to map the same in-memory file
  twice into the anonymous memory mapping the kernel requires us to always
  operate on properly aligned pages. To guarantee proper page aligment the size
  of the ringbuffer must always be a muliple of the kernel's page size. This
  also implies that the minimum size of the ringbuffer must be at least equal to
  one page size. This additional requirement is reasonably unproblematic.
  First, any ringbuffer smaller than the size of a single page is very likely
  useless since the standard page size on linux is 4096 bytes.
- Because liblxc is not able to predict the output a user is going to produce
  (e.g. users could cat binary files onto the console) and because the
  ringbuffer is located in a hotpath and needs to be as performant as possible
  liblxc will not parse the buffer.

Use Case:
The ringbuffer is needed by liblxc in order to safely log the output of write
intensive callers that produce unpredictable output or unpredictable amounts of
output. The console output created by a booting system and the user is one of
those cases. Allowing a container to log the console's output to a file it
would be possible for a malicious user to fill up the host filesystem by
producing random ouput on the container's console if quota support is either
not enabled or not available for the underlying filesystem. Using a ringbuffer
is a reliable and secure way to ensure a fixed-size log.

Closes #1857.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Fix start of Sabayon unprivileged containers

Problem happens for image with systemd >=233.
Minor fix for mirrors list.
Signed-off-by: Geaaru <geaaru@gmail.com>

fix build failures on x32

Change locale "en-US.UTF-8" to "en_US.UTF-8"

This template would always add "en-US.UTF-8" to the end of the container's locale.gen, which in turn confused locale-gen.
Signed-off-by: Fridtjof Mund <fridtjofmund@gmail.com>

log: bugfixes

Assuming a particular width of a type (or equivalence with "long") doesn't
work everywhere.  On new architectures, LFS/etc is enabled by default,
making rlim_t same as rlim64_t even if long is only 32-bit.

Not sure how you handle too big values -- you may want to re-check the
strtoull part.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>

Both of struct timespec fields are 64-bit on any new architecture, even
32-bit ones.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>

The kernel only allows 4k writes to most files in /proc including {g,u}id_map
so let's not try to write partial mappings. (This will obviously become a lot
more relevant when my patch to extend the idmap limit in the kernel is merged.)
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

lxccontainer: preserve ABI compatibility