lionsoul2014/ip2region · error

open xdb file `%s`: %w

Error message

open xdb file `%s`: %w

What it means

VerifyFromFile opens the xdb file read-only before delegating to Verify; if os.OpenFile fails, the OS error is wrapped with the file path as "open xdb file `%s`: %w". This is a path/permission problem, not a data-format problem.

Source

Thrown at binding/golang/xdb/util.go:180

	// to sure that the MaxFilePointer does no overflow
	stat, err := handle.Stat()
	if err != nil {
		return fmt.Errorf("file stat: %w", err)
	}

	maxFilePtr := (int64(1) << (runtimePtrBytes * 8)) - 1
	if stat.Size() > maxFilePtr {
		return fmt.Errorf("xdb file exceeds the maximum supported bytes: %d", maxFilePtr)
	}

	return nil
}

// VerifyFromFile check Verify for details
func VerifyFromFile(dbFile string) error {
	handle, err := os.OpenFile(dbFile, os.O_RDONLY, 0600)
	if err != nil {
		return fmt.Errorf("open xdb file `%s`: %w", dbFile, err)
	}
	defer handle.Close()

	return Verify(handle)
}

// LoadHeader load the header info from the specified handle
func LoadHeader(handle io.ReadSeeker) (*Header, error) {
	_, err := handle.Seek(0, 0)
	if err != nil {
		return nil, fmt.Errorf("seek to the header: %w", err)
	}

	var buff = make([]byte, HeaderInfoLength)
	rLen, err := handle.Read(buff)
	if err != nil {
		return nil, err
	}

View on GitHub (pinned to c1a1fc7d59)

Solutions

1. Print the resolved absolute path and check it exists with os.Stat before calling VerifyFromFile
2. Fix file permissions (chmod/chown) or run as a user with read access
3. Fix the path/environment variable pointing at the xdb file, including packaging the file in the image
4. Confirm the path is a file, not a directory

Example fix

// before
err := xdb.VerifyFromFile(os.Getenv("XDB_PATH")) // open xdb file ``: no such file or directory
// after
xdbPath := os.Getenv("XDB_PATH")
if xdbPath == "" { xdbPath = "./ip2region.xdb" }
if _, err := os.Stat(xdbPath); err != nil { log.Fatalf("xdb not found at %s", xdbPath) }
err = xdb.VerifyFromFile(xdbPath)

func resolveXDB(path string) (string, error) {
    abs, err := filepath.Abs(path)
    if err != nil { return "", err }
    info, err := os.Stat(abs)
    if err != nil { return "", fmt.Errorf("xdb %s: %w", abs, err) }
    if info.IsDir() { return "", fmt.Errorf("%s is a directory", abs) }
    f, err := os.OpenFile(abs, os.O_RDONLY, 0600)
    if err != nil { return "", err }
    f.Close()
    return abs, nil
}

if err := xdb.VerifyFromFile(dbPath); err != nil {
    var pe *os.PathError
    if errors.As(err, &pe) {
        return fmt.Errorf("cannot open xdb %s: %v (check path/permissions)", pe.Path, pe.Err)
    }
    return err
}

When it happens

Trigger: VerifyFromFile("/path/ip2region.xdb") with a nonexistent path (ENOENT), no read permission (EACCES), the path being a directory (EISDIR), or a bad symlink.

Common situations: Wrong relative path because the working directory differs in deployment; missing xdb file in a container image; running the service as a user without read access; typo'd environment variable for the db path.

Understand the failure class

Background: "open() failed", "failed to open file", "cannot create file" — what a file open error means and how to fix it — this error's family across 42 libraries.

Related errors

• file stat: %w
• invalid ip address: %s
• length of the two ips are not the same
• IPSub(%s, %s): %w
• loading header: %w

AI-assisted analysis of lionsoul2014/ip2region@c1a1fc7d59 (2026-09-02). Data as JSON: /api/errors/9355330145468d71. Report an issue: GitHub.