cgroups: refactor cgroup handling

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>

This replaces the constructor implementation of cgroup handling with a simpler,
thread-safe on-demand model of cgroup driver initialization.
Making the cgroup initialization code run in a constructor means that each time
the shared library gets mapped the cgroup parsing code gets run. That's
unnecessary overhead.
It also feels to me that this is only accidently thread-safe because
constructors are only run once. But should threads actually end up manipulating
or freeing memory that is file-global to cgfsng.c we'd be screwed. Now, I might
be wrong here but the cleaner implementation is to allocate a cgroup driver on
demand whenever we need it.
Take the chance and rework the cgroup_ops interface to make the functions it
wants to have implemented a lot cleaner.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

coverity: #1425802

Resource leak
Signed-off-by: Simos Xenitellis <simos.lists@googlemail.com>

Fixed resource leak in is_wlan() at network.c

Fixed resource leak in userns_exec_full()

capabilities: raise ambient capabilities

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Suggested-by: Jonathan Calmels <jcalmels@nvidia.com>

config: allow read-write /sys in user namespace

coverity

coverity: #1425844

Unprivileged containers can safely mount /sys as read-write. This also allows
systemd-udevd to be started in unprivileged containers.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Resource leak
Signed-off-by: Simos Xenitellis <simos.lists@googlemail.com>

Resource leak
Signed-off-by: Simos Xenitellis <simos.lists@googlemail.com>

Resource leak
Signed-off-by: Simos Xenitellis <simos.lists@googlemail.com>

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

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

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

Update Japanese man pages

fix "kB" to "KB", and tweak description. Update for commit 6d276edc and
6d276edc .
Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>

Update for commit 4160ef02Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>

tools: s/strncpy()/memcpy()/g

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

This reverts commit 2ec47d51.

First, I forgot to actually replace strncpy() with strlcpy(). Second, we don't
want to \0-terminate since this is an abstract unix socket and this is not
required. Instead, let's simply use memcpy() which is more correct and also
silences gcc-8.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

tools: s/strncpy()/strlcpy()/g

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

tree-wide: s/strncpy()/strlcpy()/g 

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>

support case ignored suffix for sizes

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

suffix of console max size and console buffer max size
Signed-off-by: l00355512 <liuhao27@huawei.com>

gcc-8: silence

The additional \0-byte space added is not needed since IFNAMSIZ needs to
include the \0-byte.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

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

confile: satisfy gcc-8