shadow1ng/fscan · error

portfinger_probe_file_empty

Error message

portfinger_probe_file_empty

What it means

parseProbesFromContent reads the probe database file and collects non-empty lines; if no lines were collected the file is considered empty and this error is returned during Init. It prevents initializing the port fingerprint engine with zero probes.

Solutions

1. Verify the probe file exists and contains probe lines (e.g. `wc -l probe.txt`), then re-supply it.
2. Re-download or restore the probe database from the upstream source.
3. Check Init's file path configuration — ensure it points at the real database, not an empty file.
4. Add a startup check that rejects zero-byte probe files with a clearer message.

Example fix

// before
err := pf.Init("/etc/app/probes.txt") // probes.txt is 0 bytes
// after
if info, err := os.Stat("/etc/app/probes.txt"); err != nil || info.Size() == 0 {
    return fmt.Errorf("probe database missing or empty")
}
err := pf.Init("/etc/app/probes.txt")

st, err := os.Stat(probePath)
if err != nil || st.Size() == 0 {
    return fmt.Errorf("probe file %s missing or empty", probePath)
}

if err := pf.Init(probePath); err != nil {
    if strings.Contains(err.Error(), "probe_file_empty") {
        return fmt.Errorf("probe database at %s is empty; restore it", probePath)
    }
    return err
}

When it happens

Trigger: Calling Init with a path to an empty probe file, or a file whose every line was skipped as blank during the read loop.

Common situations: Probe database downloaded incompletely, a file overwritten to zero bytes, wrong path pointing to an empty placeholder, or a failed update that truncated the database.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• portfinger_input_empty
• failed to create realtime backup file
• failed to create TXT file
• initialize http client
• local_pe_not_found

AI-assisted analysis of shadow1ng/fscan@95cc12e753 (2026-09-06). Data as JSON: /api/errors/75c38d9f2947af67. Report an issue: GitHub.

Appendix: source

Thrown at core/portfinger/probe_parser.go:184

// parseProbesFromContent 从内容解析探测器规则，返回错误替代 panic
func (v *VScan) parseProbesFromContent(content string) error {
	var probes []Probe
	var lines []string

	// 过滤注释和空行
	linesTemp := strings.Split(content, "\n")
	for _, lineTemp := range linesTemp {
		lineTemp = strings.TrimSpace(lineTemp)
		if lineTemp == "" || strings.HasPrefix(lineTemp, "#") {
			continue
		}
		lines = append(lines, lineTemp)
	}

	// 验证文件内容
	if len(lines) == 0 {
		return fmt.Errorf("%s", i18n.GetText("portfinger_probe_file_empty"))
	}

	// 检查Exclude指令
	excludeCount := 0
	for _, line := range lines {
		if strings.HasPrefix(line, "Exclude ") {
			excludeCount++
		}
		if excludeCount > 1 {
			return fmt.Errorf("%s", i18n.GetText("portfinger_probe_exclude_duplicate"))
		}
	}

	// 验证第一行格式
	firstLine := lines[0]
	if !strings.HasPrefix(firstLine, "Exclude ") && !strings.HasPrefix(firstLine, "Probe ") {
		return fmt.Errorf("%s", i18n.GetText("portfinger_probe_first_line_invalid"))
	}

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