github.com/mirantis/virtlet@v1.5.2-0.20191204181327-1659b8a48e9b/pkg/stream/utils.go (about)

     1  /*
     2  Copyright 2017 Mirantis
     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 stream
    18  
    19  import (
    20  	"fmt"
    21  	"io"
    22  	"io/ioutil"
    23  	"path/filepath"
    24  	"strings"
    25  )
    26  
    27  // DetachError is special error which returned in case of container detach.
    28  type DetachError struct{}
    29  
    30  func (DetachError) Error() string {
    31  	return "detached from container"
    32  }
    33  
    34  func getProcessEnvironment(pid int32) (map[string]string, error) {
    35  	envFile := filepath.Join("/proc", fmt.Sprint(pid), "environ")
    36  	all, err := ioutil.ReadFile(envFile)
    37  	if err != nil {
    38  		return nil, err
    39  	}
    40  	env := map[string]string{}
    41  
    42  	for _, v := range strings.Split(string(all), "\000") {
    43  		s := strings.SplitN(v, "=", 2)
    44  		key := s[0]
    45  		value := ""
    46  		if len(s) == 2 {
    47  			value = s[1]
    48  		}
    49  		env[key] = value
    50  	}
    51  	return env, nil
    52  }
    53  
    54  // CopyDetachable is similar to io.Copy but support a detach key sequence to break out.
    55  // based on https://github.com/kubernetes-incubator/cri-o/blob/master/utils/utils.go#L90
    56  func CopyDetachable(dst io.Writer, src io.Reader, keys []byte) (written int64, err error) {
    57  	if len(keys) == 0 {
    58  		// Default key : ^]
    59  		keys = []byte{29}
    60  	}
    61  
    62  	buf := make([]byte, 32*1024)
    63  	for {
    64  		nr, er := src.Read(buf)
    65  		if nr > 0 {
    66  			preservBuf := []byte{}
    67  			for i, key := range keys {
    68  				preservBuf = append(preservBuf, buf[0:nr]...)
    69  				if nr != 1 || buf[0] != key {
    70  					break
    71  				}
    72  				if i == len(keys)-1 {
    73  					return 0, nil
    74  				}
    75  				nr, er = src.Read(buf)
    76  			}
    77  			var nw int
    78  			var ew error
    79  			if len(preservBuf) > 0 {
    80  				nw, ew = dst.Write(preservBuf)
    81  				nr = len(preservBuf)
    82  			} else {
    83  				nw, ew = dst.Write(buf[0:nr])
    84  			}
    85  			if nw > 0 {
    86  				written += int64(nw)
    87  			}
    88  			if ew != nil {
    89  				err = ew
    90  				break
    91  			}
    92  			if nr != nw {
    93  				err = io.ErrShortWrite
    94  				break
    95  			}
    96  		}
    97  		if er != nil {
    98  			if er != io.EOF {
    99  				err = er
   100  			}
   101  			break
   102  		}
   103  	}
   104  	return written, err
   105  }