72 lines
1.9 KiB
Go
72 lines
1.9 KiB
Go
package agent
|
|
|
|
import (
|
|
"fmt"
|
|
"os"
|
|
"os/exec"
|
|
|
|
"github.com/creack/pty"
|
|
)
|
|
|
|
// PTY is a pseudo-terminal running an interactive login shell.
|
|
type PTY struct {
|
|
cmd *exec.Cmd
|
|
f *os.File
|
|
}
|
|
|
|
// StartPTY launches a login shell attached to a new PTY. With user empty (or
|
|
// equal to the agent's own user) it is the agent's shell - root by default,
|
|
// since the agent runs as a root systemd service. Any other user is entered via
|
|
// `su -l`, which only a root agent can do without a password.
|
|
func StartPTY(user string) (*PTY, error) {
|
|
var cmd *exec.Cmd
|
|
if user == "" || user == currentUser() {
|
|
cmd = exec.Command(defaultShell(), "-l")
|
|
} else {
|
|
if !validUserName(user) {
|
|
return nil, fmt.Errorf("недопустимое имя пользователя %q", user)
|
|
}
|
|
if os.Geteuid() != 0 {
|
|
return nil, fmt.Errorf("агент запущен от %s и не может открыть сессию от %s", currentUser(), user)
|
|
}
|
|
if !userExists(user) {
|
|
return nil, fmt.Errorf("пользователь %s не найден", user)
|
|
}
|
|
su, err := exec.LookPath("su")
|
|
if err != nil {
|
|
return nil, fmt.Errorf("su не найден: %w", err)
|
|
}
|
|
cmd = exec.Command(su, "-l", user)
|
|
}
|
|
cmd.Env = append(os.Environ(), "TERM=xterm-256color")
|
|
f, err := pty.Start(cmd)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return &PTY{cmd: cmd, f: f}, nil
|
|
}
|
|
|
|
// Read reads terminal output.
|
|
func (p *PTY) Read(b []byte) (int, error) { return p.f.Read(b) }
|
|
|
|
// Write writes keystrokes to the terminal.
|
|
func (p *PTY) Write(b []byte) (int, error) { return p.f.Write(b) }
|
|
|
|
// Resize changes the terminal window size.
|
|
func (p *PTY) Resize(cols, rows uint16) {
|
|
if cols == 0 || rows == 0 {
|
|
return
|
|
}
|
|
_ = pty.Setsize(p.f, &pty.Winsize{Rows: rows, Cols: cols})
|
|
}
|
|
|
|
// Close terminates the shell and releases the PTY.
|
|
func (p *PTY) Close() error {
|
|
err := p.f.Close()
|
|
if p.cmd.Process != nil {
|
|
_ = p.cmd.Process.Kill()
|
|
}
|
|
_ = p.cmd.Wait()
|
|
return err
|
|
}
|