github.com/metacubex/gvisor@v0.0.0-20240320004321-933faba989ec/pkg/shim/debug.go (about)

     1  // Copyright 2021 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     https://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package shim
    16  
    17  import (
    18  	"os"
    19  	"os/signal"
    20  	"runtime"
    21  	"sync"
    22  	"syscall"
    23  
    24  	"github.com/containerd/containerd/log"
    25  )
    26  
    27  var once sync.Once
    28  
    29  func setDebugSigHandler() {
    30  	once.Do(func() {
    31  		dumpCh := make(chan os.Signal, 1)
    32  		signal.Notify(dumpCh, syscall.SIGUSR2)
    33  		go func() {
    34  			buf := make([]byte, 10240)
    35  			for range dumpCh {
    36  				for {
    37  					n := runtime.Stack(buf, true)
    38  					if n >= len(buf) {
    39  						buf = make([]byte, 2*len(buf))
    40  						continue
    41  					}
    42  					log.L.Debugf("User requested stack trace:\n%s", buf[:n])
    43  				}
    44  			}
    45  		}()
    46  		log.L.Debugf("For full process dump run: kill -%d %d", syscall.SIGUSR2, os.Getpid())
    47  	})
    48  }