What causes "Could not list files in temp directory: {tempDir.getAbsolutePath()}" in NationalSecurityAgency/ghidra?

Check directory permissions (read + execute on the directory) for the current user.

NationalSecurityAgency/ghidra · warning · IOException

Could not list files in temp directory: {tempDir.getAbsolute

Error message

Could not list files in temp directory: {tempDir.getAbsolutePath()}

What it means

Thrown by deleteTemporaryDirectory when tempDir.listFiles() returns null. File.listFiles() returns null when the path is not a directory or when an I/O error occurs during listing. Since deleteTemporaryDirectory already checked tempDir.exists(), the most likely cause is a permission issue preventing directory enumeration, or the path was removed by another process between the exists check and the listFiles call.

Source

Thrown at Ghidra/Features/BSim/src/main/java/ghidra/features/bsim/query/ingest/BulkSignatures.java:1045

		if (dir.exists() == false) {
			if (dir.mkdir() == false) {
				throw new IOException("Unable to create temp directory: " + dir.getAbsolutePath());
			}
		}
		else if (dir.isDirectory() == false) {
			throw new IOException(dir.getAbsolutePath() + ": is not a directory");
		}
		dir = dir.getCanonicalFile();
		return dir;
	}

	private void deleteTemporaryDirectory(File tempDir) throws IOException {
		if (!tempDir.exists()) {
			return;
		}
		File[] listFiles = tempDir.listFiles();
		if (listFiles == null) {
			throw new IOException(
				"Could not list files in temp directory: " + tempDir.getAbsolutePath());
		}
		for (File listFile : listFiles) {
			if (!listFile.delete()) {
				throw new IOException(
					"Unable to delete temporary file: " + listFile.getAbsolutePath());
			}
		}
		if (!tempDir.delete()) {
			throw new IOException("Unable to delete temp directory: " + tempDir.getAbsolutePath());
		}
	}

	private class UpdateRepository extends IterateRepository {
		private File outdirectory;
		private String repo;
		private boolean overwrite;
		private DatabaseInformation info;

View on GitHub (pinned to d5f144c24d)

Solutions

Check directory permissions (read + execute on the directory) for the current user.
Use try-catch around deleteTemporaryDirectory and log the path — in cleanup contexts, best-effort deletion is often acceptable.
Ensure only one BSim process uses the same temp directory at a time.
Run with appropriate user privileges matching the process that created the temp files.

Example fix

// before
File[] listFiles = tempDir.listFiles();
if (listFiles == null) {
    throw new IOException("Could not list files in temp directory: " + tempDir.getAbsolutePath());
}

// after — best-effort cleanup with fallback
File[] listFiles = tempDir.listFiles();
if (listFiles == null) {
    if (!tempDir.delete()) {
        Msg.warn(this, "Could not list or delete temp directory: " + tempDir.getAbsolutePath());
    }
    return;
}

Defensive patterns

Strategy: validation

Validate before calling

// Check directory readability before attempting to list files
if (tempDir == null || !tempDir.exists()) {
    return; // nothing to clean
}
if (!tempDir.isDirectory()) {
    throw new IllegalStateException("Not a directory: " + tempDir.getAbsolutePath());
}
if (!tempDir.canRead()) {
    // Cannot enumerate — skip cleanup with a warning
    return;
}

Type guard

public static boolean isListableDirectory(File dir) {
    return dir != null && dir.isDirectory() && dir.canRead();
}

Try / catch

// Cleanup is best-effort — wrap in try-catch and continue
try {
    deleteTemporaryDirectory(tempDir);
} catch (IOException e) {
    // Log and continue — leftover temp files are non-fatal
    Msg.warn(BulkSignatures.class, "Temp cleanup failed: " + e.getMessage());
}

Prevention

Treat temp directory cleanup as best-effort — log failures instead of aborting.
Ensure directory permissions allow enumeration by the cleanup process.
Avoid concurrent processes sharing the same temp directory.
Run cleanup with the same user that created the temp files.

When it happens

Trigger: Calling deleteTemporaryDirectory on a path that exists but cannot be listed due to OS-level permission denial (no execute/read permission on the directory); a race condition where the directory is deleted by another process between the exists() and listFiles() calls; the path became a non-directory between checks.

Common situations: Running as a different user than the one that created the temp directory; SELinux or AppArmor blocking directory enumeration; a concurrent BSim run cleaning up the same temp directory; filesystem corruption on the temp volume.

Related errors

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/5d6789e7d30fc10f. Report an issue: GitHub.