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67 lines
2.0 KiB
67 lines
2.0 KiB
// Copyright 2019 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "brillo/scoped_mount_namespace.h"
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#include <fcntl.h>
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#include <sched.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <string>
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#include <utility>
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#include <base/posix/eintr_wrapper.h>
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#include <base/strings/stringprintf.h>
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namespace {
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constexpr char kCurrentMountNamespacePath[] = "/proc/self/ns/mnt";
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} // anonymous namespace
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namespace brillo {
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ScopedMountNamespace::ScopedMountNamespace(base::ScopedFD mount_namespace_fd)
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: mount_namespace_fd_(std::move(mount_namespace_fd)) {}
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ScopedMountNamespace::~ScopedMountNamespace() {
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PLOG_IF(ERROR, setns(mount_namespace_fd_.get(), CLONE_NEWNS) != 0)
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<< "Ignoring failure to restore original mount namespace";
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}
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// static
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std::unique_ptr<ScopedMountNamespace> ScopedMountNamespace::CreateForPid(
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pid_t pid) {
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std::string ns_path = base::StringPrintf("/proc/%d/ns/mnt", pid);
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return CreateFromPath(base::FilePath(ns_path));
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}
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// static
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std::unique_ptr<ScopedMountNamespace> ScopedMountNamespace::CreateFromPath(
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const base::FilePath& ns_path) {
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base::ScopedFD original_mount_namespace_fd(
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HANDLE_EINTR(open(kCurrentMountNamespacePath, O_RDONLY)));
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if (!original_mount_namespace_fd.is_valid()) {
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PLOG(ERROR) << "Failed to open original mount namespace FD at "
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<< kCurrentMountNamespacePath;
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return nullptr;
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}
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base::ScopedFD mount_namespace_fd(
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HANDLE_EINTR(open(ns_path.value().c_str(), O_RDONLY)));
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if (!mount_namespace_fd.is_valid()) {
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PLOG(ERROR) << "Failed to open mount namespace FD at " << ns_path.value();
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return nullptr;
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}
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if (setns(mount_namespace_fd.get(), CLONE_NEWNS) != 0) {
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PLOG(ERROR) << "Failed to enter mount namespace at " << ns_path.value();
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return nullptr;
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}
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return std::make_unique<ScopedMountNamespace>(
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std::move(original_mount_namespace_fd));
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}
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} // namespace brillo
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