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// Copyright 2018 Google LLC
//
// 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.
package boot
import (
"fmt"
"sync"
"syscall"
specs "github.com/opencontainers/runtime-spec/specs-go"
"gvisor.googlesource.com/gvisor/pkg/log"
"gvisor.googlesource.com/gvisor/pkg/sentry/limits"
)
// Mapping from linux resource names to limits.LimitType.
var fromLinuxResource = map[string]limits.LimitType{
"RLIMIT_AS": limits.AS,
"RLIMIT_CORE": limits.Core,
"RLIMIT_CPU": limits.CPU,
"RLIMIT_DATA": limits.Data,
"RLIMIT_FSIZE": limits.FileSize,
"RLIMIT_LOCKS": limits.Locks,
"RLIMIT_MEMLOCK": limits.MemoryLocked,
"RLIMIT_MSGQUEUE": limits.MessageQueueBytes,
"RLIMIT_NICE": limits.Nice,
"RLIMIT_NOFILE": limits.NumberOfFiles,
"RLIMIT_NPROC": limits.ProcessCount,
"RLIMIT_RSS": limits.Rss,
"RLIMIT_RTPRIO": limits.RealTimePriority,
"RLIMIT_RTTIME": limits.Rttime,
"RLIMIT_SIGPENDING": limits.SignalsPending,
"RLIMIT_STACK": limits.Stack,
}
func findName(lt limits.LimitType) string {
for k, v := range fromLinuxResource {
if v == lt {
return k
}
}
return "unknown"
}
var defaults defs
type defs struct {
mu sync.Mutex
set *limits.LimitSet
err error
}
func (d *defs) get() (*limits.LimitSet, error) {
d.mu.Lock()
defer d.mu.Unlock()
if d.err != nil {
return nil, d.err
}
if d.set == nil {
if err := d.initDefaults(); err != nil {
d.err = err
return nil, err
}
}
return d.set, nil
}
func (d *defs) initDefaults() error {
ls, err := limits.NewLinuxLimitSet()
if err != nil {
return err
}
// Set default limits based on what containers get by default, ex:
// $ docker run --rm debian prlimit
ls.SetUnchecked(limits.AS, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.Core, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.CPU, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.Data, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.FileSize, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.Locks, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.MemoryLocked, limits.Limit{Cur: 65536, Max: 65536})
ls.SetUnchecked(limits.MessageQueueBytes, limits.Limit{Cur: 819200, Max: 819200})
ls.SetUnchecked(limits.Nice, limits.Limit{Cur: 0, Max: 0})
ls.SetUnchecked(limits.NumberOfFiles, limits.Limit{Cur: 1048576, Max: 1048576})
ls.SetUnchecked(limits.ProcessCount, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.Rss, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.RealTimePriority, limits.Limit{Cur: 0, Max: 0})
ls.SetUnchecked(limits.Rttime, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.SignalsPending, limits.Limit{Cur: 0, Max: 0})
ls.SetUnchecked(limits.Stack, limits.Limit{Cur: 8388608, Max: limits.Infinity})
// Read host limits that directly affect the sandbox and adjust the defaults
// based on them.
for _, res := range []int{syscall.RLIMIT_FSIZE, syscall.RLIMIT_NOFILE} {
var hl syscall.Rlimit
if err := syscall.Getrlimit(res, &hl); err != nil {
return err
}
lt, ok := limits.FromLinuxResource[res]
if !ok {
return fmt.Errorf("unknown rlimit type %v", res)
}
hostLimit := limits.Limit{
Cur: limits.FromLinux(hl.Cur),
Max: limits.FromLinux(hl.Max),
}
defaultLimit := ls.Get(lt)
if hostLimit.Cur != limits.Infinity && hostLimit.Cur < defaultLimit.Cur {
log.Warningf("Host limit is lower than recommended, resource: %q, host: %d, recommended: %d", findName(lt), hostLimit.Cur, defaultLimit.Cur)
}
if hostLimit.Cur != defaultLimit.Cur || hostLimit.Max != defaultLimit.Max {
log.Infof("Setting limit from host, resource: %q {soft: %d, hard: %d}", findName(lt), hostLimit.Cur, hostLimit.Max)
ls.SetUnchecked(lt, hostLimit)
}
}
d.set = ls
return nil
}
func createLimitSet(spec *specs.Spec) (*limits.LimitSet, error) {
ls, err := defaults.get()
if err != nil {
return nil, err
}
// Then apply overwrites on top of defaults.
for _, rl := range spec.Process.Rlimits {
lt, ok := fromLinuxResource[rl.Type]
if !ok {
return nil, fmt.Errorf("unknown resource %q", rl.Type)
}
ls.SetUnchecked(lt, limits.Limit{
Cur: rl.Soft,
Max: rl.Hard,
})
}
return ls, nil
}
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