github.com/nicocha30/gvisor-ligolo@v0.0.0-20230726075806-989fa2c0a413/pkg/shim/service_linux.go (about)

     1  // Copyright 2018 The containerd Authors.
     2  // Copyright 2018 The gVisor 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  //     https://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  //go:build linux
    17  // +build linux
    18  
    19  package shim
    20  
    21  import (
    22  	"context"
    23  	"fmt"
    24  	"io"
    25  	"sync"
    26  
    27  	"github.com/containerd/console"
    28  	"github.com/containerd/fifo"
    29  	"golang.org/x/sys/unix"
    30  )
    31  
    32  type linuxPlatform struct {
    33  	epoller *console.Epoller
    34  }
    35  
    36  func (p *linuxPlatform) CopyConsole(ctx context.Context, console console.Console, stdin, stdout, stderr string, wg *sync.WaitGroup) (console.Console, error) {
    37  	if p.epoller == nil {
    38  		return nil, fmt.Errorf("uninitialized epoller")
    39  	}
    40  
    41  	epollConsole, err := p.epoller.Add(console)
    42  	if err != nil {
    43  		return nil, err
    44  	}
    45  
    46  	if stdin != "" {
    47  		in, err := fifo.OpenFifo(context.Background(), stdin, unix.O_RDONLY|unix.O_NONBLOCK, 0)
    48  		if err != nil {
    49  			return nil, err
    50  		}
    51  		go func() {
    52  			p := bufPool.Get().(*[]byte)
    53  			defer bufPool.Put(p)
    54  			io.CopyBuffer(epollConsole, in, *p)
    55  		}()
    56  	}
    57  
    58  	outw, err := fifo.OpenFifo(ctx, stdout, unix.O_WRONLY, 0)
    59  	if err != nil {
    60  		return nil, err
    61  	}
    62  	outr, err := fifo.OpenFifo(ctx, stdout, unix.O_RDONLY, 0)
    63  	if err != nil {
    64  		return nil, err
    65  	}
    66  	wg.Add(1)
    67  	go func() {
    68  		p := bufPool.Get().(*[]byte)
    69  		defer bufPool.Put(p)
    70  		io.CopyBuffer(outw, epollConsole, *p)
    71  		epollConsole.Close()
    72  		outr.Close()
    73  		outw.Close()
    74  		wg.Done()
    75  	}()
    76  	return epollConsole, nil
    77  }
    78  
    79  func (p *linuxPlatform) ShutdownConsole(ctx context.Context, cons console.Console) error {
    80  	if p.epoller == nil {
    81  		return fmt.Errorf("uninitialized epoller")
    82  	}
    83  	epollConsole, ok := cons.(*console.EpollConsole)
    84  	if !ok {
    85  		return fmt.Errorf("expected EpollConsole, got %#v", cons)
    86  	}
    87  	return epollConsole.Shutdown(p.epoller.CloseConsole)
    88  }
    89  
    90  func (p *linuxPlatform) Close() error {
    91  	return p.epoller.Close()
    92  }
    93  
    94  // initialize a single epoll fd to manage our consoles. `initPlatform` should
    95  // only be called once.
    96  func (s *service) initPlatform() error {
    97  	if s.platform != nil {
    98  		return nil
    99  	}
   100  	epoller, err := console.NewEpoller()
   101  	if err != nil {
   102  		return fmt.Errorf("failed to initialize epoller: %w", err)
   103  	}
   104  	s.platform = &linuxPlatform{
   105  		epoller: epoller,
   106  	}
   107  	go epoller.Wait()
   108  	return nil
   109  }