github.com/coreos/mantle@v0.13.0/platform/util.go (about)

     1  // Copyright 2015 CoreOS, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package platform
    16  
    17  import (
    18  	"context"
    19  	"crypto/rand"
    20  	"crypto/rsa"
    21  	"fmt"
    22  	"os"
    23  
    24  	"golang.org/x/crypto/ssh"
    25  	"golang.org/x/crypto/ssh/terminal"
    26  )
    27  
    28  // Manhole connects os.Stdin, os.Stdout, and os.Stderr to an interactive shell
    29  // session on the Machine m. Manhole blocks until the shell session has ended.
    30  // If os.Stdin does not refer to a TTY, Manhole returns immediately with a nil
    31  // error.
    32  func Manhole(m Machine) error {
    33  	fd := int(os.Stdin.Fd())
    34  	if !terminal.IsTerminal(fd) {
    35  		return nil
    36  	}
    37  
    38  	tstate, _ := terminal.MakeRaw(fd)
    39  	defer terminal.Restore(fd, tstate)
    40  
    41  	client, err := m.SSHClient()
    42  	if err != nil {
    43  		return fmt.Errorf("SSH client failed: %v", err)
    44  	}
    45  
    46  	defer client.Close()
    47  
    48  	session, err := client.NewSession()
    49  	if err != nil {
    50  		return fmt.Errorf("SSH session failed: %v", err)
    51  	}
    52  
    53  	defer session.Close()
    54  
    55  	session.Stdin = os.Stdin
    56  	session.Stdout = os.Stdout
    57  	session.Stderr = os.Stderr
    58  
    59  	modes := ssh.TerminalModes{
    60  		ssh.TTY_OP_ISPEED: 115200,
    61  		ssh.TTY_OP_OSPEED: 115200,
    62  	}
    63  
    64  	cols, lines, err := terminal.GetSize(int(os.Stdin.Fd()))
    65  	if err != nil {
    66  		return err
    67  	}
    68  
    69  	if err = session.RequestPty(os.Getenv("TERM"), lines, cols, modes); err != nil {
    70  		return fmt.Errorf("failed to request pseudo terminal: %s", err)
    71  	}
    72  
    73  	if err := session.Shell(); err != nil {
    74  		return fmt.Errorf("failed to start shell: %s", err)
    75  	}
    76  
    77  	if err := session.Wait(); err != nil {
    78  		return fmt.Errorf("failed to wait for session: %s", err)
    79  	}
    80  
    81  	return nil
    82  }
    83  
    84  // Enable SELinux on a machine (skip on machines without SELinux support)
    85  func EnableSelinux(m Machine) error {
    86  	_, stderr, err := m.SSH("if type -P setenforce; then sudo setenforce 1; fi")
    87  	if err != nil {
    88  		return fmt.Errorf("Unable to enable SELinux: %s: %s", err, stderr)
    89  	}
    90  	return nil
    91  }
    92  
    93  // Reboots a machine, stopping ssh first.
    94  // Afterwards run CheckMachine to verify the system is back and operational.
    95  func StartReboot(m Machine) error {
    96  	// stop sshd so that commonMachineChecks will only work if the machine
    97  	// actually rebooted
    98  	out, stderr, err := m.SSH("sudo systemctl stop sshd.socket && sudo reboot")
    99  	if _, ok := err.(*ssh.ExitMissingError); ok {
   100  		// A terminated session is perfectly normal during reboot.
   101  		err = nil
   102  	}
   103  	if err != nil {
   104  		return fmt.Errorf("issuing reboot command failed: %s: %s: %s", out, err, stderr)
   105  	}
   106  	return nil
   107  }
   108  
   109  // RebootMachine will reboot a given machine, provided the machine's journal.
   110  func RebootMachine(m Machine, j *Journal) error {
   111  	if err := StartReboot(m); err != nil {
   112  		return fmt.Errorf("machine %q failed to begin rebooting: %v", m.ID(), err)
   113  	}
   114  	return StartMachine(m, j)
   115  }
   116  
   117  // StartMachine will start a given machine, provided the machine's journal.
   118  func StartMachine(m Machine, j *Journal) error {
   119  	if err := j.Start(context.TODO(), m); err != nil {
   120  		return fmt.Errorf("machine %q failed to start: %v", m.ID(), err)
   121  	}
   122  	if err := CheckMachine(context.TODO(), m); err != nil {
   123  		return fmt.Errorf("machine %q failed basic checks: %v", m.ID(), err)
   124  	}
   125  	if !m.RuntimeConf().NoEnableSelinux {
   126  		if err := EnableSelinux(m); err != nil {
   127  			return fmt.Errorf("machine %q failed to enable selinux: %v", m.ID(), err)
   128  		}
   129  	}
   130  	return nil
   131  }
   132  
   133  // GenerateFakeKey generates a SSH key pair, returns the public key, and
   134  // discards the private key. This is useful for droplets that don't need a
   135  // public key, since DO & Azure insists on requiring one.
   136  func GenerateFakeKey() (string, error) {
   137  	rsaKey, err := rsa.GenerateKey(rand.Reader, 2048)
   138  	if err != nil {
   139  		return "", err
   140  	}
   141  	sshKey, err := ssh.NewPublicKey(&rsaKey.PublicKey)
   142  	if err != nil {
   143  		return "", err
   144  	}
   145  	return string(ssh.MarshalAuthorizedKey(sshKey)), nil
   146  }