github.com/containerd/Containerd@v1.4.13/runtime/v1/shim/service_linux.go (about)

     1  /*
     2     Copyright The containerd Authors.
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package shim
    18  
    19  import (
    20  	"context"
    21  	"io"
    22  	"sync"
    23  	"syscall"
    24  
    25  	"github.com/containerd/console"
    26  	"github.com/containerd/fifo"
    27  	"github.com/pkg/errors"
    28  )
    29  
    30  type linuxPlatform struct {
    31  	epoller *console.Epoller
    32  }
    33  
    34  func (p *linuxPlatform) CopyConsole(ctx context.Context, console console.Console, stdin, stdout, stderr string, wg *sync.WaitGroup) (console.Console, error) {
    35  	if p.epoller == nil {
    36  		return nil, errors.New("uninitialized epoller")
    37  	}
    38  
    39  	epollConsole, err := p.epoller.Add(console)
    40  	if err != nil {
    41  		return nil, err
    42  	}
    43  	var cwg sync.WaitGroup
    44  
    45  	if stdin != "" {
    46  		in, err := fifo.OpenFifo(ctx, stdin, syscall.O_RDONLY, 0)
    47  		if err != nil {
    48  			return nil, err
    49  		}
    50  		cwg.Add(1)
    51  		go func() {
    52  			cwg.Done()
    53  			bp := bufPool.Get().(*[]byte)
    54  			defer bufPool.Put(bp)
    55  			io.CopyBuffer(epollConsole, in, *bp)
    56  			// we need to shutdown epollConsole when pipe broken
    57  			epollConsole.Shutdown(p.epoller.CloseConsole)
    58  			epollConsole.Close()
    59  		}()
    60  	}
    61  
    62  	outw, err := fifo.OpenFifo(ctx, stdout, syscall.O_WRONLY, 0)
    63  	if err != nil {
    64  		return nil, err
    65  	}
    66  	outr, err := fifo.OpenFifo(ctx, stdout, syscall.O_RDONLY, 0)
    67  	if err != nil {
    68  		return nil, err
    69  	}
    70  	wg.Add(1)
    71  	cwg.Add(1)
    72  	go func() {
    73  		cwg.Done()
    74  		p := bufPool.Get().(*[]byte)
    75  		defer bufPool.Put(p)
    76  		io.CopyBuffer(outw, epollConsole, *p)
    77  		outw.Close()
    78  		outr.Close()
    79  		wg.Done()
    80  	}()
    81  	cwg.Wait()
    82  	return epollConsole, nil
    83  }
    84  
    85  func (p *linuxPlatform) ShutdownConsole(ctx context.Context, cons console.Console) error {
    86  	if p.epoller == nil {
    87  		return errors.New("uninitialized epoller")
    88  	}
    89  	epollConsole, ok := cons.(*console.EpollConsole)
    90  	if !ok {
    91  		return errors.Errorf("expected EpollConsole, got %#v", cons)
    92  	}
    93  	return epollConsole.Shutdown(p.epoller.CloseConsole)
    94  }
    95  
    96  func (p *linuxPlatform) Close() error {
    97  	return p.epoller.Close()
    98  }
    99  
   100  // initialize a single epoll fd to manage our consoles. `initPlatform` should
   101  // only be called once.
   102  func (s *Service) initPlatform() error {
   103  	if s.platform != nil {
   104  		return nil
   105  	}
   106  	epoller, err := console.NewEpoller()
   107  	if err != nil {
   108  		return errors.Wrap(err, "failed to initialize epoller")
   109  	}
   110  	s.platform = &linuxPlatform{
   111  		epoller: epoller,
   112  	}
   113  	go epoller.Wait()
   114  	return nil
   115  }