/*
|
* Copyright (c) 2017 Facebook, Inc.
|
* Copyright (c) 2017 VMware, Inc.
|
*
|
* 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.
|
*/
|
|
#include <fcntl.h>
|
#include <sched.h>
|
#include <sys/stat.h>
|
#include <string>
|
|
#include "ns_guard.h"
|
|
// TODO: Remove this when CentOS 6 support is not needed anymore
|
#include "setns.h"
|
|
ProcMountNS::ProcMountNS(int pid) : target_ino_(0) {
|
if (pid < 0)
|
return;
|
|
std::string target_path = "/proc/" + std::to_string(pid) + "/ns/mnt";
|
ebpf::FileDesc target_fd(open(target_path.c_str(), O_RDONLY));
|
ebpf::FileDesc self_fd(open("/proc/self/ns/mnt", O_RDONLY));
|
|
if (self_fd < 0 || target_fd < 0)
|
return;
|
|
struct stat self_stat, target_stat;
|
if (fstat(self_fd, &self_stat) != 0)
|
return;
|
if (fstat(target_fd, &target_stat) != 0)
|
return;
|
|
target_ino_ = target_stat.st_ino;
|
if (self_stat.st_ino == target_stat.st_ino)
|
// Both current and target Process are in same mount namespace
|
return;
|
|
self_fd_ = std::move(self_fd);
|
target_fd_ = std::move(target_fd);
|
}
|
|
ProcMountNSGuard::ProcMountNSGuard(ProcMountNS *mount_ns)
|
: mount_ns_instance_(nullptr), mount_ns_(mount_ns), entered_(false) {
|
init();
|
}
|
|
ProcMountNSGuard::ProcMountNSGuard(int pid)
|
: mount_ns_instance_(pid > 0 ? new ProcMountNS(pid) : nullptr),
|
mount_ns_(mount_ns_instance_.get()),
|
entered_(false) {
|
init();
|
}
|
|
void ProcMountNSGuard::init() {
|
if (!mount_ns_ || mount_ns_->self() < 0 || mount_ns_->target() < 0)
|
return;
|
|
if (setns(mount_ns_->target(), CLONE_NEWNS) == 0)
|
entered_ = true;
|
}
|
|
ProcMountNSGuard::~ProcMountNSGuard() {
|
if (mount_ns_ && entered_ && mount_ns_->self() >= 0)
|
setns(mount_ns_->self(), CLONE_NEWNS);
|
}
|
