90 lines
2.8 KiB
Go
90 lines
2.8 KiB
Go
package codespaces
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"os"
|
|
"os/exec"
|
|
"strconv"
|
|
"strings"
|
|
)
|
|
|
|
// Shell runs an interactive secure shell over an existing
|
|
// port-forwarding session. It runs until the shell is terminated
|
|
// (including by cancellation of the context).
|
|
func Shell(ctx context.Context, log logger, sshArgs []string, port int, destination string, usingCustomPort bool) error {
|
|
cmd, connArgs, err := newSSHCommand(ctx, port, destination, sshArgs)
|
|
if err != nil {
|
|
return fmt.Errorf("failed to create ssh command: %w", err)
|
|
}
|
|
|
|
if usingCustomPort {
|
|
log.Println("Connection Details: ssh " + destination + " " + strings.Join(connArgs, " "))
|
|
}
|
|
|
|
return cmd.Run()
|
|
}
|
|
|
|
// NewRemoteCommand returns an exec.Cmd that will securely run a shell
|
|
// command on the remote machine.
|
|
func NewRemoteCommand(ctx context.Context, tunnelPort int, destination string, sshArgs ...string) (*exec.Cmd, error) {
|
|
cmd, _, err := newSSHCommand(ctx, tunnelPort, destination, sshArgs)
|
|
return cmd, err
|
|
}
|
|
|
|
// newSSHCommand populates an exec.Cmd to run a command (or if blank,
|
|
// an interactive shell) over ssh.
|
|
func newSSHCommand(ctx context.Context, port int, dst string, cmdArgs []string) (*exec.Cmd, []string, error) {
|
|
connArgs := []string{"-p", strconv.Itoa(port), "-o", "NoHostAuthenticationForLocalhost=yes"}
|
|
|
|
// The ssh command syntax is: ssh [flags] user@host command [args...]
|
|
// There is no way to specify the user@host destination as a flag.
|
|
// Unfortunately, that means we need to know which user-provided words are
|
|
// SSH flags and which are command arguments so that we can place
|
|
// them before or after the destination, and that means we need to know all
|
|
// the flags and their arities.
|
|
cmdArgs, command, err := parseSSHArgs(cmdArgs)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
|
|
cmdArgs = append(cmdArgs, connArgs...)
|
|
cmdArgs = append(cmdArgs, "-C") // Compression
|
|
cmdArgs = append(cmdArgs, dst) // user@host
|
|
|
|
if command != nil {
|
|
cmdArgs = append(cmdArgs, command...)
|
|
}
|
|
|
|
cmd := exec.CommandContext(ctx, "ssh", cmdArgs...)
|
|
cmd.Stdout = os.Stdout
|
|
cmd.Stdin = os.Stdin
|
|
cmd.Stderr = os.Stderr
|
|
|
|
return cmd, connArgs, nil
|
|
}
|
|
|
|
// parseSSHArgs parses SSH arguments into two distinct slices of flags and command.
|
|
// It returns an error if a unary flag is provided without an argument.
|
|
func parseSSHArgs(args []string) (cmdArgs, command []string, err error) {
|
|
for i := 0; i < len(args); i++ {
|
|
arg := args[i]
|
|
|
|
// if we've started parsing the command, set it to the rest of the args
|
|
if !strings.HasPrefix(arg, "-") {
|
|
command = args[i:]
|
|
break
|
|
}
|
|
|
|
cmdArgs = append(cmdArgs, arg)
|
|
if len(arg) == 2 && strings.Contains("bcDeFIiLlmOopRSWw", arg[1:2]) {
|
|
if i++; i == len(args) {
|
|
return nil, nil, fmt.Errorf("ssh flag: %s requires an argument", arg)
|
|
}
|
|
|
|
cmdArgs = append(cmdArgs, args[i])
|
|
}
|
|
}
|
|
|
|
return cmdArgs, command, nil
|
|
}
|