github.com/containerd/containerd@v22.0.0-20200918172823-438c87b8e050+incompatible/cmd/ctr/commands/shim/io_unix.go (about)

     1  // +build !windows
     2  
     3  /*
     4     Copyright The containerd Authors.
     5  
     6     Licensed under the Apache License, Version 2.0 (the "License");
     7     you may not use this file except in compliance with the License.
     8     You may obtain a copy of the License at
     9  
    10         http://www.apache.org/licenses/LICENSE-2.0
    11  
    12     Unless required by applicable law or agreed to in writing, software
    13     distributed under the License is distributed on an "AS IS" BASIS,
    14     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    15     See the License for the specific language governing permissions and
    16     limitations under the License.
    17  */
    18  
    19  package shim
    20  
    21  import (
    22  	gocontext "context"
    23  	"io"
    24  	"os"
    25  	"sync"
    26  
    27  	"github.com/containerd/fifo"
    28  	"golang.org/x/sys/unix"
    29  )
    30  
    31  var bufPool = sync.Pool{
    32  	New: func() interface{} {
    33  		buffer := make([]byte, 32<<10)
    34  		return &buffer
    35  	},
    36  }
    37  
    38  func prepareStdio(stdin, stdout, stderr string, console bool) (wg *sync.WaitGroup, err error) {
    39  	wg = &sync.WaitGroup{}
    40  	ctx := gocontext.Background()
    41  
    42  	f, err := fifo.OpenFifo(ctx, stdin, unix.O_WRONLY|unix.O_CREAT|unix.O_NONBLOCK, 0700)
    43  	if err != nil {
    44  		return nil, err
    45  	}
    46  	defer func(c io.Closer) {
    47  		if err != nil {
    48  			c.Close()
    49  		}
    50  	}(f)
    51  	go func(w io.WriteCloser) {
    52  		p := bufPool.Get().(*[]byte)
    53  		defer bufPool.Put(p)
    54  		io.CopyBuffer(w, os.Stdin, *p)
    55  		w.Close()
    56  	}(f)
    57  
    58  	f, err = fifo.OpenFifo(ctx, stdout, unix.O_RDONLY|unix.O_CREAT|unix.O_NONBLOCK, 0700)
    59  	if err != nil {
    60  		return nil, err
    61  	}
    62  	defer func(c io.Closer) {
    63  		if err != nil {
    64  			c.Close()
    65  		}
    66  	}(f)
    67  	wg.Add(1)
    68  	go func(r io.ReadCloser) {
    69  		io.Copy(os.Stdout, r)
    70  		r.Close()
    71  		wg.Done()
    72  	}(f)
    73  
    74  	f, err = fifo.OpenFifo(ctx, stderr, unix.O_RDONLY|unix.O_CREAT|unix.O_NONBLOCK, 0700)
    75  	if err != nil {
    76  		return nil, err
    77  	}
    78  	defer func(c io.Closer) {
    79  		if err != nil {
    80  			c.Close()
    81  		}
    82  	}(f)
    83  	if !console {
    84  		wg.Add(1)
    85  		go func(r io.ReadCloser) {
    86  			io.Copy(os.Stderr, r)
    87  			r.Close()
    88  			wg.Done()
    89  		}(f)
    90  	}
    91  
    92  	return wg, nil
    93  }