Current File : //usr/lib/python3/dist-packages/bcc/containers.py
# Copyright 2020 Kinvolk GmbH
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
def _cgroup_filter_func_writer(cgroupmap):
if not cgroupmap:
return """
static inline int _cgroup_filter() {
return 0;
}
"""
text = """
BPF_TABLE_PINNED("hash", u64, u64, cgroupset, 1024, "CGROUP_PATH");
static inline int _cgroup_filter() {
u64 cgroupid = bpf_get_current_cgroup_id();
return cgroupset.lookup(&cgroupid) == NULL;
}
"""
return text.replace('CGROUP_PATH', cgroupmap)
def _mntns_filter_func_writer(mntnsmap):
if not mntnsmap:
return """
static inline int _mntns_filter() {
return 0;
}
"""
text = """
#include <linux/nsproxy.h>
#include <linux/mount.h>
#include <linux/ns_common.h>
/* see mountsnoop.py:
* XXX: struct mnt_namespace is defined in fs/mount.h, which is private
* to the VFS and not installed in any kernel-devel packages. So, let's
* duplicate the important part of the definition. There are actually
* more members in the real struct, but we don't need them, and they're
* more likely to change.
*/
struct mnt_namespace {
// This field was removed in https://github.com/torvalds/linux/commit/1a7b8969e664d6af328f00fe6eb7aabd61a71d13
#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 11, 0)
atomic_t count;
#endif
struct ns_common ns;
};
/*
* To add mountsnoop support for --selector option, we need to call
* filter_by_containers().
* This function adds code which defines struct mnt_namespace.
* The problem is that this struct is also defined in mountsnoop BPF code.
* To avoid redefining it in mountnsoop code, we define
* MNT_NAMESPACE_DEFINED here.
* Then, in mountsnoop code, the struct mnt_namespace definition is guarded
* by:
* #ifndef MNT_NAMESPACE_DEFINED
* // ...
* #endif
*/
#define MNT_NAMESPACE_DEFINED
BPF_TABLE_PINNED("hash", u64, u32, mount_ns_set, 1024, "MOUNT_NS_PATH");
static inline int _mntns_filter() {
struct task_struct *current_task;
struct nsproxy *nsproxy;
struct mnt_namespace *mnt_ns;
unsigned int inum;
u64 ns_id;
current_task = (struct task_struct *)bpf_get_current_task();
if (bpf_probe_read_kernel(&nsproxy, sizeof(nsproxy), ¤t_task->nsproxy))
return 0;
if (bpf_probe_read_kernel(&mnt_ns, sizeof(mnt_ns), &nsproxy->mnt_ns))
return 0;
if (bpf_probe_read_kernel(&inum, sizeof(inum), &mnt_ns->ns.inum))
return 0;
ns_id = (u64) inum;
return mount_ns_set.lookup(&ns_id) == NULL;
}
"""
return text.replace('MOUNT_NS_PATH', mntnsmap)
def filter_by_containers(args):
filter_by_containers_text = """
static inline int container_should_be_filtered() {
return _cgroup_filter() || _mntns_filter();
}
"""
cgroupmap_text = _cgroup_filter_func_writer(args.cgroupmap)
mntnsmap_text = _mntns_filter_func_writer(args.mntnsmap)
return cgroupmap_text + mntnsmap_text + filter_by_containers_text
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