feat: initial commit

internal/agent/terminal.go

@@ -0,0 +1,54 @@
+package agent
+
+import (
+	"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 the shell attached to a new PTY. The agent runs as root
+// (systemd User=root), so this is a root shell by design.
+func StartPTY() (*PTY, error) {
+	shell := "/bin/bash"
+	if _, err := os.Stat(shell); err != nil {
+		shell = "/bin/sh"
+	}
+	cmd := exec.Command(shell, "-l")
+	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
+}