github.com/StackPointCloud/packer@v0.10.2-0.20180716202532-b28098e0f79b/builder/amazon/chroot/communicator.go (about)

     1  package chroot
     2  
     3  import (
     4  	"bytes"
     5  	"fmt"
     6  	"io"
     7  	"io/ioutil"
     8  	"log"
     9  	"os"
    10  	"os/exec"
    11  	"path/filepath"
    12  	"strings"
    13  	"syscall"
    14  
    15  	"github.com/hashicorp/packer/packer"
    16  )
    17  
    18  // Communicator is a special communicator that works by executing
    19  // commands locally but within a chroot.
    20  type Communicator struct {
    21  	Chroot     string
    22  	CmdWrapper CommandWrapper
    23  }
    24  
    25  func (c *Communicator) Start(cmd *packer.RemoteCmd) error {
    26  	command, err := c.CmdWrapper(
    27  		fmt.Sprintf("chroot %s /bin/sh -c \"%s\"", c.Chroot, cmd.Command))
    28  	if err != nil {
    29  		return err
    30  	}
    31  
    32  	localCmd := ShellCommand(command)
    33  	localCmd.Stdin = cmd.Stdin
    34  	localCmd.Stdout = cmd.Stdout
    35  	localCmd.Stderr = cmd.Stderr
    36  	log.Printf("Executing: %s %#v", localCmd.Path, localCmd.Args)
    37  	if err := localCmd.Start(); err != nil {
    38  		return err
    39  	}
    40  
    41  	go func() {
    42  		exitStatus := 0
    43  		if err := localCmd.Wait(); err != nil {
    44  			if exitErr, ok := err.(*exec.ExitError); ok {
    45  				exitStatus = 1
    46  
    47  				// There is no process-independent way to get the REAL
    48  				// exit status so we just try to go deeper.
    49  				if status, ok := exitErr.Sys().(syscall.WaitStatus); ok {
    50  					exitStatus = status.ExitStatus()
    51  				}
    52  			}
    53  		}
    54  
    55  		log.Printf(
    56  			"Chroot execution exited with '%d': '%s'",
    57  			exitStatus, cmd.Command)
    58  		cmd.SetExited(exitStatus)
    59  	}()
    60  
    61  	return nil
    62  }
    63  
    64  func (c *Communicator) Upload(dst string, r io.Reader, fi *os.FileInfo) error {
    65  	dst = filepath.Join(c.Chroot, dst)
    66  	log.Printf("Uploading to chroot dir: %s", dst)
    67  	tf, err := ioutil.TempFile("", "packer-amazon-chroot")
    68  	if err != nil {
    69  		return fmt.Errorf("Error preparing shell script: %s", err)
    70  	}
    71  	defer os.Remove(tf.Name())
    72  
    73  	if _, err := io.Copy(tf, r); err != nil {
    74  		return err
    75  	}
    76  
    77  	cpCmd, err := c.CmdWrapper(fmt.Sprintf("cp %s %s", tf.Name(), dst))
    78  	if err != nil {
    79  		return err
    80  	}
    81  
    82  	return ShellCommand(cpCmd).Run()
    83  }
    84  
    85  func (c *Communicator) UploadDir(dst string, src string, exclude []string) error {
    86  	// If src ends with a trailing "/", copy from "src/." so that
    87  	// directory contents (including hidden files) are copied, but the
    88  	// directory "src" is omitted.  BSD does this automatically when
    89  	// the source contains a trailing slash, but linux does not.
    90  	if src[len(src)-1] == '/' {
    91  		src = src + "."
    92  	}
    93  
    94  	// TODO: remove any file copied if it appears in `exclude`
    95  	chrootDest := filepath.Join(c.Chroot, dst)
    96  
    97  	log.Printf("Uploading directory '%s' to '%s'", src, chrootDest)
    98  	cpCmd, err := c.CmdWrapper(fmt.Sprintf("cp -R '%s' %s", src, chrootDest))
    99  	if err != nil {
   100  		return err
   101  	}
   102  
   103  	var stderr bytes.Buffer
   104  	cmd := ShellCommand(cpCmd)
   105  	cmd.Env = append(cmd.Env, "LANG=C")
   106  	cmd.Env = append(cmd.Env, os.Environ()...)
   107  	cmd.Stderr = &stderr
   108  	err = cmd.Run()
   109  	if err == nil {
   110  		return err
   111  	}
   112  
   113  	if strings.Contains(stderr.String(), "No such file") {
   114  		// This just means that the directory was empty. Just ignore it.
   115  		return nil
   116  	}
   117  
   118  	return err
   119  }
   120  
   121  func (c *Communicator) DownloadDir(src string, dst string, exclude []string) error {
   122  	return fmt.Errorf("DownloadDir is not implemented for amazon-chroot")
   123  }
   124  
   125  func (c *Communicator) Download(src string, w io.Writer) error {
   126  	src = filepath.Join(c.Chroot, src)
   127  	log.Printf("Downloading from chroot dir: %s", src)
   128  	f, err := os.Open(src)
   129  	if err != nil {
   130  		return err
   131  	}
   132  	defer f.Close()
   133  
   134  	if _, err := io.Copy(w, f); err != nil {
   135  		return err
   136  	}
   137  
   138  	return nil
   139  }