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ca1a482e9e
SSH catches SIGTERM, tears down its connection, then exits with platform-specific exit code.
124 lines
2.6 KiB
Go
124 lines
2.6 KiB
Go
package sshbytestream
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import (
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"fmt"
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"io"
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"os"
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"runtime"
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"syscall"
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"github.com/zrepl/zrepl/util"
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)
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type Error struct {
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Stderr []byte
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WaitErr error
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}
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func (e Error) Error() string {
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return fmt.Sprintf("ssh command failed with error: %v. stderr:\n%s\n", e.WaitErr, e.Stderr)
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}
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type SSHTransport struct {
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Host string
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User string
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Port uint16
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IdentityFile string
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SSHCommand string
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Options []string
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}
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var SSHCommand string = "ssh"
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var SSHServerAliveInterval uint = 60
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func Incoming() (wc io.ReadWriteCloser, err error) {
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// derivce ReadWriteCloser from stdin & stdout
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return IncomingReadWriteCloser{}, nil
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}
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type IncomingReadWriteCloser struct{}
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func (f IncomingReadWriteCloser) Read(p []byte) (n int, err error) {
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return os.Stdin.Read(p)
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}
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func (f IncomingReadWriteCloser) Write(p []byte) (n int, err error) {
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return os.Stdout.Write(p)
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}
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func (f IncomingReadWriteCloser) Close() (err error) {
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if err = os.Stdin.Close(); err != nil {
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return
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}
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if err = os.Stdout.Close(); err != nil {
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return
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}
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return
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}
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type OutgoingSSHByteStream struct {
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c *util.IOCommand
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}
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func Outgoing(remote SSHTransport) (s OutgoingSSHByteStream, err error) {
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sshArgs := make([]string, 0, 2*len(remote.Options)+4)
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sshArgs = append(sshArgs,
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"-p", fmt.Sprintf("%d", remote.Port),
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"-q",
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"-i", remote.IdentityFile,
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"-o", "BatchMode=yes",
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"-o", fmt.Sprintf("ServerAliveInterval=%d", SSHServerAliveInterval),
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)
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for _, option := range remote.Options {
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sshArgs = append(sshArgs, "-o", option)
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}
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sshArgs = append(sshArgs, fmt.Sprintf("%s@%s", remote.User, remote.Host))
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var sshCommand = SSHCommand
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if len(remote.SSHCommand) > 0 {
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sshCommand = SSHCommand
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}
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if s.c, err = util.NewIOCommand(sshCommand, sshArgs, util.IOCommandStderrBufSize); err != nil {
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return
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}
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// Clear environment of cmd, ssh shall not rely on SSH_AUTH_SOCK, etc.
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s.c.Cmd.Env = []string{}
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err = s.c.Start()
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return
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}
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func (s OutgoingSSHByteStream) Read(p []byte) (n int, err error) {
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return s.c.Read(p)
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}
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func (s OutgoingSSHByteStream) Write(p []byte) (n int, err error) {
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return s.c.Write(p)
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}
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func (s OutgoingSSHByteStream) Close() (err error) {
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err = s.c.Close()
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if err == nil || s.c.ExitResult == nil {
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return
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}
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// SSH catches SIGTERM and has different exit codes on different platforms
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ws := s.c.ExitResult.WaitStatus
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switch runtime.GOOS {
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case "linux":
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if ws.ExitStatus() == 128+int(syscall.SIGTERM) { // OpenSSH_7.5p1, OpenSSL 1.1.0f 25 May 2017 Arch Linux
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err = nil
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}
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case "freebsd": // OpenSSH_7.2p2, OpenSSL 1.0.2k-freebsd 26 Jan 2017
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if ws.ExitStatus() == 255 {
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err = nil
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}
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default: // TODO
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}
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return
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}
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