Quoting Stéphane Graber (stgra...@ubuntu.com):
> This introduces a new add_devices() call to the python API.
>
> Parameters:
> - path => Mandatory, path to a character or block device on the host
> - destpath => Optional, alternative path inside the container
>
> The function will allow the node in the container's devices cgroup and
> then create the entry in the container.
>
> Signed-off-by: Stéphane Graber <stgra...@ubuntu.com>
> ---
> src/python-lxc/lxc/__init__.py | 61
> ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 61 insertions(+)
>
> diff --git a/src/python-lxc/lxc/__init__.py b/src/python-lxc/lxc/__init__.py
> index 4da3d41..c572e10 100644
> --- a/src/python-lxc/lxc/__init__.py
> +++ b/src/python-lxc/lxc/__init__.py
> @@ -25,6 +25,7 @@ import _lxc
> import glob
> import os
> import subprocess
> +import stat
> import tempfile
> import time
> import warnings
> @@ -149,6 +150,66 @@ class Container(_lxc.Container):
> _lxc.Container.__init__(self, name)
> self.network = ContainerNetworkList(self)
>
> + def add_device(self, path, destpath=None):
> + """
> + Add device to running container.
> + """
> +
> + if not destpath:
> + destpath = path
> +
> + if not os.path.exists(path):
> + return False
> +
> + # Lookup the source
> + path_stat = os.stat(path)
> + mode = stat.S_IMODE(path_stat.st_mode)
> +
> + # Lookup the cgroup
> + cgroup_path = None
> + with open("/proc/%s/cgroup" % self.init_pid, "r") as fd:
> + for line in fd:
> + if ":devices:" in line:
> + cgroup_path = line.split(":")[-1].strip()
> + break
> + else:
> + return False
> +
> + # Lookup the cgroup mount point
> + cgroup = None
> + with open("/proc/mounts", "r") as fd:
> + for line in fd:
> + mount = line.split()
> + if (mount[2] == "cgroup" and "devices" in mount[3]
> + and os.path.exists("%s/%s" % (mount[1],
> cgroup_path))):
> + cgroup = "%s/%s" % (mount[1], cgroup_path)
> + break
The cgroup tweaking should be done using generic code. Maybe it's
time to add those to the c api...
> + if not os.path.exists(cgroup):
> + return False
> +
> + # Allow the target
> + with open("%s/devices.allow" % cgroup, "a") as fd:
> + if stat.S_ISBLK(path_stat.st_mode):
> + fd.write("b %s:%s rwm" % (int(path_stat.st_rdev / 256),
> + int(path_stat.st_rdev % 256)))
> + elif stat.S_ISCHR(path_stat.st_mode):
> + fd.write("c %s:%s rwm" % (int(path_stat.st_rdev / 256),
> + int(path_stat.st_rdev % 256)))
> +
> + # Create the target
> + rootfs = "/proc/%s/root/" % self.init_pid
> + container_path = "%s/%s" % (rootfs, destpath)
> +
> + if os.path.exists(container_path):
> + os.remove(container_path)
> +
> + os.mknod(container_path, path_stat.st_mode, path_stat.st_rdev)
> + os.chmod(container_path, mode)
> + os.chown(container_path, 0, 0)
This brings up an interesting question of persistence. The device node
will be persistent if using static /dev, not with autodev. The cgroup
settings are not saved here that I can see.
Do we want persistence to be an option? If so we could optionally save
the cgroup settings and add a new config file entry for device entries
to add in the case of autodev. HOWEVER, there will also be cases where
the device being added can change its major:minor between container
startups. In which case we have deeper problems (and need to bind to
a uuid or lspci/lsusb device descriptor or something).
> + return True
> +
> def append_config_item(self, key, value):
> """
> Append 'value' to 'key', assuming 'key' is a list.
> --
> 1.8.0
>
>
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