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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

This function safely parses an unsigned integer. On success it returns 0 and
stores the unsigned integer in @converted. On error it returns a negative
errno.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

If the file "/sys/devices/system/cpu/isolated" doesn't exist, we can't just
simply bail. We still need to check whether we need to copy the parents cpu
settings.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

- add more logging
- only write to cpuset.cpus if we really have to
- simplify cleanup on error and success
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

Move the user namespace at the first position in the array so that we always
attach to it first when iterating over the struct and using setns() to switch
namespaces. This especially affects lxc_attach(): Suppose you cloned a new user
namespace and mount namespace as an unprivileged user on the host and want to
setns() to the mount namespace. This requires you to attach to the user
namespace first otherwise the kernel will fail this check:

    if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
        !ns_capable(current_user_ns(), CAP_SYS_CHROOT) ||
        !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
    	return -EPERM;

in

    linux/fs/namespace.c:mntns_install().
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

Using custom structs in attach.c risks getting out of sync with the commonly
used ns_info[LXC_NS_MAX] struct and thus attaching to wrong namespaces. Switch
to using ns_info[LXC_NS_MAX].
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

- simply check /proc/self/ns
- improve SYSERROR() report
- use #define to prevent gcc & clang to use a VLA
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

It's much more appropriate there and makes start.{c,h} cleaner and leaner.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

Improve log and comments in a bunch of places to make it easier for us on bug
reports.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

- Allocating an error message that the caller must free seems pointless. We can
  just print the error message in preserve_ns() itself. This also allows us to
  avoid using the GNU extension asprintf().
- Improve lxc_preserve_ns(): By passing in NULL or "" as the second argument
  the function can now also be used to check whether namespaces are supported
  by the kernel.
- Use lxc_preserve_ns() in preserve_ns().
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

- So far we blindly called lxc_delete_network() to make sure that we deleted
  all network interfaces. This resulted in pointless netlink calls, especially
  when a container had multiple networks defined. Let's be smarter and have
  lxc_delete_network() return a boolean that indicates whether *all* configured
  networks have been deleted. If so, don't needlessly try to delete them again
  in start.c. This also decreases confusing error messages a user might see.

- When we receive -ENODEV from one of our lxc_netdev_delete_*() functions,
  let's assume that either the network device already got deleted or that it
  got moved to a different network namespace. Inform the user about this but do
  not report an error in this case.

- When we have explicitly deleted the host side of a veth pair let's
  immediately free(priv.veth_attr.pair) and NULL it, or
  memset(priv.veth_attr.pair, ...) the corresponding member so we don't
  needlessly try to destroy them again when we have to call
  lxc_delete_network() again in start.c
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

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

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

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

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

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

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

This allows to retrieve a file descriptor referring to a namespace.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

When we set LXC_DEBUG_CGFSNG=1 we print out info about detected cgroup
hierarchies. When there's no named cgroup mounted we need to make sure that we
don't try to index an unallocated pointer.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>