java-native-access/jna · error · IOException

errno: " + Native.getLastError()

Error message

errno: " + Native.getLastError()

What it means

Generic errno sentinel thrown by the ExtAttr helpers when the FreeBSD extattr_syscall(2) call (list/get/set) returns -1. The real cause is in the appended errno value — e.g. ENOATTR (attribute not found), ENOENT (bad path), EPERM/EACCES (not owner or no permission on the filesystem), or ENOTSUP (filesystem without extended attributes, e.g. UFS without ACL support).

Solutions

1. Read the errno in the message and map it: 2 = ENOENT (check path), 87/ENOATTR = missing attribute, 13 = EACCES (permissions)
2. Verify the filesystem supports extended attributes and the process owns the file or runs with privileges
3. Use l* variants / correct EXTATTR namespace if the attribute lives in a different namespace

When it happens

Trigger: Thrown at contrib/platform/src/com/sun/jna/platform/bsd/ExtAttrUtil.java:44 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of java-native-access/jna@d036ad9781 (2026-09-12). Data as JSON: /api/errors/7dc36df3ba076923. Report an issue: GitHub.

Appendix: source

Thrown at contrib/platform/src/com/sun/jna/platform/bsd/ExtAttrUtil.java:44

import static java.util.Collections.*;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;

import com.sun.jna.Native;
import com.sun.jna.platform.unix.LibCAPI.size_t;

public class ExtAttrUtil {

    public static List<String> list(String path) throws IOException {
        // get required buffer size
        long bufferLength = ExtAttr.INSTANCE.extattr_list_file(path, ExtAttr.EXTATTR_NAMESPACE_USER, null, new size_t(0)).longValue();

        if (bufferLength < 0) {
            throw new IOException("errno: " + Native.getLastError());
        }

        if (bufferLength == 0) {
            return emptyList();
        }

        ByteBuffer buffer = ByteBuffer.allocate((int) bufferLength);
        long valueLength = ExtAttr.INSTANCE.extattr_list_file(path, ExtAttr.EXTATTR_NAMESPACE_USER, buffer, new size_t(bufferLength)).longValue();

        if (valueLength < 0) {
            throw new IOException("errno: " + Native.getLastError());
        }

        return decodeStringList(buffer);
    }

    public static ByteBuffer get(String path, String name) throws IOException {
        // get required buffer size

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