// Copyright (C) 2023 Opsmate, Inc. // // This Source Code Form is subject to the terms of the Mozilla // Public License, v. 2.0. If a copy of the MPL was not distributed // with this file, You can obtain one at http://mozilla.org/MPL/2.0/. // // This software is distributed WITHOUT A WARRANTY OF ANY KIND. // See the Mozilla Public License for details. package monitor import ( "bytes" "context" "errors" "fmt" "io/fs" "os" "os/exec" "path/filepath" "strings" "sync" "time" ) var stdoutMu sync.Mutex type notification struct { environ []string summary string text string } func (s *FilesystemState) notify(ctx context.Context, notif *notification) error { if s.Stdout { writeToStdout(notif) } if len(s.Email) > 0 { if err := sendEmail(ctx, s.Email, notif); err != nil { return err } } if s.Script != "" { if err := execScript(ctx, s.Script, notif); err != nil { return err } } if s.ScriptDir != "" { if err := execScriptDir(ctx, s.ScriptDir, notif); err != nil { return err } } return nil } func writeToStdout(notif *notification) { stdoutMu.Lock() defer stdoutMu.Unlock() os.Stdout.WriteString(notif.text + "\n") } func sendEmail(ctx context.Context, to []string, notif *notification) error { stdin := new(bytes.Buffer) stderr := new(bytes.Buffer) fmt.Fprintf(stdin, "To: %s\n", strings.Join(to, ", ")) fmt.Fprintf(stdin, "Subject: [certspotter] %s\n", notif.summary) fmt.Fprintf(stdin, "Date: %s\n", time.Now().Format(mailDateFormat)) fmt.Fprintf(stdin, "Message-ID: <%s>\n", generateMessageID()) fmt.Fprintf(stdin, "Mime-Version: 1.0\n") fmt.Fprintf(stdin, "Content-Type: text/plain; charset=US-ASCII\n") fmt.Fprintf(stdin, "X-Mailer: certspotter\n") fmt.Fprintf(stdin, "\n") fmt.Fprint(stdin, notif.text) args := []string{"-i", "--"} args = append(args, to...) sendmail := exec.CommandContext(ctx, sendmailPath(), args...) sendmail.Stdin = stdin sendmail.Stderr = stderr if err := sendmail.Run(); err == nil { return nil } else if ctx.Err() != nil { return ctx.Err() } else if exitErr, isExitError := err.(*exec.ExitError); isExitError && exitErr.Exited() { return fmt.Errorf("error sending email to %v: sendmail failed with exit code %d and error %q", to, exitErr.ExitCode(), strings.TrimSpace(stderr.String())) } else { return fmt.Errorf("error sending email to %v: %w", to, err) } } func execScript(ctx context.Context, scriptName string, notif *notification) error { stderr := new(bytes.Buffer) cmd := exec.CommandContext(ctx, scriptName) cmd.Env = os.Environ() cmd.Env = append(cmd.Env, notif.environ...) cmd.Stderr = stderr if err := cmd.Run(); err == nil { return nil } else if ctx.Err() != nil { return ctx.Err() } else if exitErr, isExitError := err.(*exec.ExitError); isExitError && exitErr.Exited() { return fmt.Errorf("script %q exited with code %d and error %q", scriptName, exitErr.ExitCode(), strings.TrimSpace(stderr.String())) } else if isExitError { return fmt.Errorf("script %q terminated by signal with error %q", scriptName, strings.TrimSpace(stderr.String())) } else { return fmt.Errorf("error executing script: %w", err) } } func execScriptDir(ctx context.Context, dirPath string, notif *notification) error { dirents, err := os.ReadDir(dirPath) if errors.Is(err, fs.ErrNotExist) { return nil } else if err != nil { return fmt.Errorf("error executing scripts in directory %q: %w", dirPath, err) } for _, dirent := range dirents { if strings.HasPrefix(dirent.Name(), ".") { continue } scriptPath := filepath.Join(dirPath, dirent.Name()) info, err := os.Stat(scriptPath) if errors.Is(err, fs.ErrNotExist) { continue } else if err != nil { return fmt.Errorf("error executing %q in directory %q: %w", dirent.Name(), dirPath, err) } else if info.Mode().IsRegular() && isExecutable(info.Mode()) { if err := execScript(ctx, scriptPath, notif); err != nil { return err } } } return nil } func isExecutable(mode os.FileMode) bool { return mode&0111 != 0 }