mirror of https://github.com/k3s-io/k3s
101 lines
3.8 KiB
Go
101 lines
3.8 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package sysctl
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import (
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"io/ioutil"
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"path"
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"strconv"
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"strings"
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)
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const (
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sysctlBase = "/proc/sys"
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// VMOvercommitMemory refers to the sysctl variable responsible for defining
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// the memory over-commit policy used by kernel.
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VMOvercommitMemory = "vm/overcommit_memory"
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// VMPanicOnOOM refers to the sysctl variable responsible for defining
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// the OOM behavior used by kernel.
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VMPanicOnOOM = "vm/panic_on_oom"
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// KernelPanic refers to the sysctl variable responsible for defining
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// the timeout after a panic for the kernel to reboot.
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KernelPanic = "kernel/panic"
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// KernelPanicOnOops refers to the sysctl variable responsible for defining
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// the kernel behavior when an oops or BUG is encountered.
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KernelPanicOnOops = "kernel/panic_on_oops"
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// RootMaxKeys refers to the sysctl variable responsible for defining
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// the maximum number of keys that the root user (UID 0 in the root user namespace) may own.
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RootMaxKeys = "kernel/keys/root_maxkeys"
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// RootMaxBytes refers to the sysctl variable responsible for defining
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// the maximum number of bytes of data that the root user (UID 0 in the root user namespace)
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// can hold in the payloads of the keys owned by root.
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RootMaxBytes = "kernel/keys/root_maxbytes"
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// VMOvercommitMemoryAlways represents that kernel performs no memory over-commit handling.
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VMOvercommitMemoryAlways = 1
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// VMPanicOnOOMInvokeOOMKiller represents that kernel calls the oom_killer function when OOM occurs.
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VMPanicOnOOMInvokeOOMKiller = 0
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// KernelPanicOnOopsAlways represents that kernel panics on kernel oops.
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KernelPanicOnOopsAlways = 1
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// KernelPanicRebootTimeout is the timeout seconds after a panic for the kernel to reboot.
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KernelPanicRebootTimeout = 10
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// RootMaxKeysSetting is the maximum number of keys that the root user (UID 0 in the root user namespace) may own.
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// Needed since docker creates a new key per container.
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RootMaxKeysSetting = 1000000
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// RootMaxBytesSetting is the maximum number of bytes of data that the root user (UID 0 in the root user namespace)
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// can hold in the payloads of the keys owned by root.
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// Allocate 25 bytes per key * number of MaxKeys.
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RootMaxBytesSetting = RootMaxKeysSetting * 25
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)
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// Interface is an injectable interface for running sysctl commands.
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type Interface interface {
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// GetSysctl returns the value for the specified sysctl setting
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GetSysctl(sysctl string) (int, error)
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// SetSysctl modifies the specified sysctl flag to the new value
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SetSysctl(sysctl string, newVal int) error
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}
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// New returns a new Interface for accessing sysctl
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func New() Interface {
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return &procSysctl{}
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}
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// procSysctl implements Interface by reading and writing files under /proc/sys
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type procSysctl struct {
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}
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// GetSysctl returns the value for the specified sysctl setting
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func (*procSysctl) GetSysctl(sysctl string) (int, error) {
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data, err := ioutil.ReadFile(path.Join(sysctlBase, sysctl))
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if err != nil {
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return -1, err
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}
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val, err := strconv.Atoi(strings.Trim(string(data), " \n"))
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if err != nil {
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return -1, err
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}
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return val, nil
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}
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// SetSysctl modifies the specified sysctl flag to the new value
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func (*procSysctl) SetSysctl(sysctl string, newVal int) error {
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return ioutil.WriteFile(path.Join(sysctlBase, sysctl), []byte(strconv.Itoa(newVal)), 0640)
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}
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