inspektor-gadget

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// Copyright 2021 The Inspektor Gadget authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//     http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package netnsenter
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import (
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	"runtime"
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	"github.com/vishvananda/netns"
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	"github.com/inspektor-gadget/inspektor-gadget/pkg/utils/host"
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	netnsig "github.com/inspektor-gadget/inspektor-gadget/pkg/utils/netns"
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)
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func NetnsEnter(pid int, f func() error) error {
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	if pid == 0 {
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		return f()
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	}
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	// Lock the OS Thread so we don't accidentally switch namespaces
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	runtime.LockOSThread()
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	defer runtime.UnlockOSThread()
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	// Save the current network namespace
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	origns, _ := netns.Get()
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	defer origns.Close()
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	netnsHandle, err := netnsig.GetFromPidWithAltProcfs(pid, host.HostProcFs)
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	if err != nil {
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		return err
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	}
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	defer netnsHandle.Close()
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	err = netns.Set(netnsHandle)
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	if err != nil {
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		return err
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	}
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	// Switch back to the original namespace
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	defer netns.Set(origns)
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	return f()
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}
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