/// <summary>
/// Combines the exception data into a single generic message string.
/// </summary>
/// <param name="nativeMethodName">Name of the native API method which returned the error code.</param>
/// <param name="errorCode">Native error code of this exception.</param>
/// <param name="errno">Value of errno.</param>
/// <param name="errnoString">The string representation of errno.</param>
private static string BuildExceptionMessageString(string nativeMethodName, NativeErrorCodes errorCode, long errno, string errnoString)
{
string prefix = $"Error in {nativeMethodName}: ";
string functionErrnoSuffix = $"() failed with errno = {errnoString} [{errno}].";
return(prefix + errorCode switch
{
NativeErrorCodes.NATIVE_ERROR_OPEN_FAILED => prefix + "open" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_FSTAT_FAILED => prefix + "fstat" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_GET_ACL_FAILED => prefix + "acl_get_fd" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_GET_ACL_ENTRY_FAILED => prefix + "acl_get_entry" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_GET_ACL_ENTRY_TAG_TYPE_FAILED => prefix + "acl_get_tag_type" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_GET_ACL_ENTRY_QUALIFIER_FAILED => prefix + "acl_get_qualifier" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_GET_ACL_ENTRY_PERMSET_FAILED => prefix + "acl_get_permset" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_GET_ACL_ENTRY_PERM_FAILED => prefix + "acl_get_perm" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_CHOWN_FAILED => prefix + "fchown" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_CHMOD_FAILED => prefix + "fchmod" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_INIT_ACL_FAILED => prefix + "acl_init" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_CREATE_ACL_ENTRY_FAILED => prefix + "acl_create_entry" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_INVALID_TAG_TYPE => prefix + "The given entry tag type was invalid.",
NativeErrorCodes.NATIVE_ERROR_SET_ACL_ENTRY_TAG_TYPE_FAILED => prefix + "acl_set_tag_type" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_SET_ACL_ENTRY_QUALIFIER_FAILED => prefix + "acl_set_qualifier" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_CLEAR_ACL_ENTRY_PERMS_FAILED => prefix + "acl_clear_perms" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_ADD_ACL_ENTRY_PERM_FAILED => prefix + "acl_add_perm" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_VALIDATE_ACL_FAILED => prefix + "acl_valid" + functionErrnoSuffix,
NativeErrorCodes.NATIVE_ERROR_SET_ACL_FAILED => prefix + "acl_set_file" + functionErrnoSuffix,
_ => "Unknown native error.",
});
/// <summary>
/// Creates a new exception from the given native error code and errno value, using the given exception message.
/// </summary>
/// <param name="nativeFunctionName">Name of the native API method which returned the error code.</param>
/// <param name="errorCode">Native error code of this exception.</param>
/// <param name="errno">Value of errno (or 0, if not applicable).</param>
/// <param name="errnoString">The string representation of errno (if applicable).</param>
/// <param name="message">The exception message to display.</param>
protected NativeException(string nativeMethodName, NativeErrorCodes errorCode, long errno, string errnoString, string message)
: base(message)
{
NativeMethodName = nativeMethodName;
ErrorCode = errorCode;
Errno = errno;
ErrnoString = errnoString;
}
/// <inheritdoc />
/// <exception cref="UnauthorizedAccessException">Thrown when trying to open or modify a file/directory without having sufficient access permissions.</exception>
/// <exception cref="FileNotFoundException">Thrown when a file/directory or parts of its path cannot be found.</exception>
/// <exception cref="ArgumentException">Thrown when the provided ACL is invalid.</exception>
/// <exception cref="NativeException">Generic exception thrown when a native method fails, and the error was not covered by one of the other possible exceptions. This exception is also always included as the <see cref="Exception.InnerException"/>.</exception>
public void SetPermissionData(string fileName, int setDefaultAcl, ref NativePermissionDataContainer dataContainer, AccessControlListEntry[] entries)
{
// Ensure exclusive access to native functions
lock (_nativeFunctionsLock)
{
// Make sure the meta data object is valid
dataContainer.AclSize = entries.Length;
// Set permissions and ACL
NativeErrorCodes err = SetFilePermissionDataAndAcl(fileName, setDefaultAcl, ref dataContainer, entries);
if (err != NativeErrorCodes.NATIVE_ERROR_SUCCESS)
{
// Throw suitable exceptions
var nativeException = RetrieveErrnoAndBuildException(nameof(SetFilePermissionDataAndAcl), err, out var _, out var errnoSymbolic);
switch (err)
{
// Handle certain special exception cases
case NativeErrorCodes.NATIVE_ERROR_OPEN_FAILED when errnoSymbolic == Errno.EACCES:
throw new UnauthorizedAccessException($"Could not open \"{fileName}\" for reading.", nativeException);
case NativeErrorCodes.NATIVE_ERROR_OPEN_FAILED when errnoSymbolic == Errno.ENOENT:
throw new FileNotFoundException($"Could not open \"{fileName}\" for reading.", nativeException);
case NativeErrorCodes.NATIVE_ERROR_CHOWN_FAILED when errnoSymbolic == Errno.EPERM:
throw new UnauthorizedAccessException($"Permission denied when using fchown() on \"{fileName}\".", nativeException);
case NativeErrorCodes.NATIVE_ERROR_CHMOD_FAILED when errnoSymbolic == Errno.EPERM:
throw new UnauthorizedAccessException($"Permission denied when using fchmod() on \"{fileName}\".", nativeException);
case NativeErrorCodes.NATIVE_ERROR_VALIDATE_ACL_FAILED when errnoSymbolic == Errno.EINVAL:
throw new ArgumentException($"The given ACL is invalid.", nativeException);
case NativeErrorCodes.NATIVE_ERROR_SET_ACL_FAILED when errnoSymbolic == Errno.EINVAL:
throw new ArgumentException($"Could not assign ACL to file \"{fileName}\" using acl_set_fd().", nativeException);
case NativeErrorCodes.NATIVE_ERROR_SET_ACL_FAILED when errnoSymbolic == Errno.EPERM:
throw new UnauthorizedAccessException($"Permission denied when assigning ACL using acl_set_fd() on \"{fileName}\".", nativeException);
// Unhandled case, just throw generic exception directly
default:
throw nativeException;
}
}
}
}
/// <inheritdoc />
/// <exception cref="UnauthorizedAccessException">Thrown when trying to open a file/directory without having sufficient access permissions.</exception>
/// <exception cref="FileNotFoundException">Thrown when a file/directory or parts of its path cannot be found.</exception>
/// <exception cref="NativeException">Generic exception thrown when a native method fails, and the error was not covered by one of the other possible exceptions. This exception is also always included as the <see cref="Exception.InnerException"/>.</exception>
public AccessControlListEntry[] GetPermissionData(string fileName, int loadDefaultAcl, out NativePermissionDataContainer dataContainer)
{
// Ensure exclusive access to native functions
lock (_nativeFunctionsLock)
{
// Read permission data and retrieve ACL size
NativeErrorCodes err = OpenFileAndReadPermissionData(fileName, loadDefaultAcl, out dataContainer);
if (err != NativeErrorCodes.NATIVE_ERROR_SUCCESS)
{
// Throw suitable exceptions
var nativeException = RetrieveErrnoAndBuildException(nameof(OpenFileAndReadPermissionData), err, out var _, out var errnoSymbolic);
switch (err)
{
// Handle certain special exception cases
case NativeErrorCodes.NATIVE_ERROR_OPEN_FAILED when errnoSymbolic == Errno.EACCES:
throw new UnauthorizedAccessException($"Could not open \"{fileName}\" for reading.", nativeException);
case NativeErrorCodes.NATIVE_ERROR_OPEN_FAILED when errnoSymbolic == Errno.ENOENT:
throw new FileNotFoundException($"Could not open \"{fileName}\" for reading.", nativeException);
// Unhandled case, just throw generic exception directly
default:
throw nativeException;
}
}
// Read ACL
AccessControlListEntry[] acl = new AccessControlListEntry[dataContainer.AclSize];
err = ReadFileAclAndClose(acl);
if (err != NativeErrorCodes.NATIVE_ERROR_SUCCESS)
{
throw RetrieveErrnoAndBuildException(nameof(ReadFileAclAndClose), err, out var _, out var _);
}
return(acl);
}
}
/// <summary>
/// Creates a new exception from the given native error code and errno value.
/// </summary>
/// <param name="nativeFunctionName">Name of the native API method which returned the error code.</param>
/// <param name="errorCode">Native error code of this exception.</param>
/// <param name="errno">Value of errno (or 0, if not applicable).</param>
/// <param name="errnoString">The string representation of errno (if applicable).</param>
internal NativeException(string nativeMethodName, NativeErrorCodes errorCode, long errno, string errnoString)
: this(nativeMethodName, errorCode, errno, errnoString, BuildExceptionMessageString(nativeMethodName, errorCode, errno, errnoString))
{
}
/// <summary>
/// Retrieves the error information from the native implementation and constructs a new <see cref="NativeException"/> object, that can be thrown afterwards.
/// </summary>
/// <param name="nativeMethodName">Name of the native API method which returned the error code.</param>
/// <param name="errorCode">The error code returned by the native API method.</param>
/// <param name="errnoResolvable">This will tell whether the retrieved errno could be resolved into a symbolic representation.</param>
/// <param name="errnoSymbolic">This will hold the symbolic value of the retrieved errno; check the <paramref name="errnoResolvable"/> parameter beforehand!</param>
private NativeException RetrieveErrnoAndBuildException(string nativeMethodName, NativeErrorCodes errorCode, out bool errnoResolvable, out Errno errnoSymbolic)
{
// Retrieve errno
var errnoStringBuffer = new StringBuilder(256);
long errno = GetLastErrnoValue(errnoStringBuffer, errnoStringBuffer.Capacity);
// Try to resolve to symbolic representation
errnoResolvable = NativeConvert.TryToErrno((int)errno, out errnoSymbolic);
// Create native exception object
return(new NativeException(nativeMethodName, errorCode, errno, (errnoResolvable ? errnoSymbolic.ToString() + ", " : "") + errnoStringBuffer.ToString()));
}
