nsxfobj.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

/*******************************************************************************
 *
 * Module Name: nsxfobj - Public interfaces to the ACPI subsystem
 *                         ACPI Object oriented interfaces
 *              $Revision: 95 $
 *
 ******************************************************************************/

/*
 *  Copyright (C) 2000, 2001 R. Byron Moore
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


#include "acpi.h"
#include "acinterp.h"
#include "acnamesp.h"
#include "acdispat.h"


#define _COMPONENT          ACPI_NAMESPACE
	 MODULE_NAME         ("nsxfobj")


/*******************************************************************************
 *
 * FUNCTION:    Acpi_evaluate_object
 *
 * PARAMETERS:  Handle              - Object handle (optional)
 *              *Pathname           - Object pathname (optional)
 *              **External_params   - List of parameters to pass to method,
 *                                    terminated by NULL.  May be NULL
 *                                    if no parameters are being passed.
 *              *Return_buffer      - Where to put method's return value (if
 *                                    any).  If NULL, no value is returned.
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Find and evaluate the given object, passing the given
 *              parameters if necessary.  One of "Handle" or "Pathname" must
 *              be valid (non-null)
 *
 ******************************************************************************/

acpi_status
acpi_evaluate_object (
	acpi_handle             handle,
	acpi_string             pathname,
	acpi_object_list        *external_params,
	acpi_buffer             *return_buffer)
{
	acpi_status             status;
	acpi_operand_object     **internal_params = NULL;
	acpi_operand_object     *internal_return_obj = NULL;
	u32                     buffer_space_needed;
	u32                     user_buffer_length;
	u32                     i;


	FUNCTION_TRACE ("Acpi_evaluate_object");


	/*
	 * If there are parameters to be passed to the object
	 * (which must be a control method), the external objects
	 * must be converted to internal objects
	 */
	if (external_params && external_params->count) {
		/*
		 * Allocate a new parameter block for the internal objects
		 * Add 1 to count to allow for null terminated internal list
		 */
		internal_params = ACPI_MEM_CALLOCATE ((external_params->count + 1) * sizeof (void *));
		if (!internal_params) {
			return_ACPI_STATUS (AE_NO_MEMORY);
		}


		/*
		 * Convert each external object in the list to an
		 * internal object
		 */
		for (i = 0; i < external_params->count; i++) {
			status = acpi_ut_copy_eobject_to_iobject (&external_params->pointer[i],
					 &internal_params[i]);

			if (ACPI_FAILURE (status)) {
				acpi_ut_delete_internal_object_list (internal_params);
				return_ACPI_STATUS (status);
			}
		}
		internal_params[external_params->count] = NULL;
	}


	/*
	 * Three major cases:
	 * 1) Fully qualified pathname
	 * 2) No handle, not fully qualified pathname (error)
	 * 3) Valid handle
	 */
	if ((pathname) &&
		(acpi_ns_valid_root_prefix (pathname[0]))) {
		/*
		 *  The path is fully qualified, just evaluate by name
		 */
		status = acpi_ns_evaluate_by_name (pathname, internal_params, &internal_return_obj);
	}

	else if (!handle) {
		/*
		 * A handle is optional iff a fully qualified pathname
		 * is specified.  Since we've already handled fully
		 * qualified names above, this is an error
		 */
		if (!pathname) {
			ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Both Handle and Pathname are NULL\n"));
		}

		else {
			ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Handle is NULL and Pathname is relative\n"));
		}

		status = AE_BAD_PARAMETER;
	}

	else {
		/*
		 * We get here if we have a handle -- and if we have a
		 * pathname it is relative.  The handle will be validated
		 * in the lower procedures
		 */
		if (!pathname) {
			/*
			 * The null pathname case means the handle is for
			 * the actual object to be evaluated
			 */
			status = acpi_ns_evaluate_by_handle (handle, internal_params, &internal_return_obj);
		}

		else {
		   /*
			* Both a Handle and a relative Pathname
			*/
			status = acpi_ns_evaluate_relative (handle, pathname, internal_params,
					 &internal_return_obj);
		}
	}


	/*
	 * If we are expecting a return value, and all went well above,
	 * copy the return value to an external object.
	 */

	if (return_buffer) {
		user_buffer_length = return_buffer->length;
		return_buffer->length = 0;

		if (internal_return_obj) {
			if (VALID_DESCRIPTOR_TYPE (internal_return_obj, ACPI_DESC_TYPE_NAMED)) {
				/*
				 * If we got an Node as a return object,
				 * this means the object we are evaluating
				 * has nothing interesting to return (such
				 * as a mutex, etc.)  We return an error
				 * because these types are essentially
				 * unsupported by this interface.  We
				 * don't check up front because this makes
				 * it easier to add support for various
				 * types at a later date if necessary.
				 */
				status = AE_TYPE;
				internal_return_obj = NULL; /* No need to delete an Node */
			}

			if (ACPI_SUCCESS (status)) {
				/*
				 * Find out how large a buffer is needed
				 * to contain the returned object
				 */
				status = acpi_ut_get_object_size (internal_return_obj,
						   &buffer_space_needed);
				if (ACPI_SUCCESS (status)) {
					/*
					 * Check if there is enough room in the
					 * caller's buffer
					 */
					if (user_buffer_length < buffer_space_needed) {
						/*
						 * Caller's buffer is too small, can't
						 * give him partial results fail the call
						 * but return the buffer size needed
						 */
						ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
							"Needed buffer size %X, received %X\n",
							buffer_space_needed, user_buffer_length));

						return_buffer->length = buffer_space_needed;
						status = AE_BUFFER_OVERFLOW;
					}

					else {
						/*
						 *  We have enough space for the object, build it
						 */
						status = acpi_ut_copy_iobject_to_eobject (internal_return_obj,
								  return_buffer);
						return_buffer->length = buffer_space_needed;
					}
				}
			}
		}
	}


	/* Delete the return and parameter objects */

	if (internal_return_obj) {
		/*
		 * Delete the internal return object. (Or at least
		 * decrement the reference count by one)
		 */
		acpi_ut_remove_reference (internal_return_obj);
	}

	/*
	 * Free the input parameter list (if we created one),
	 */
	if (internal_params) {
		/* Free the allocated parameter block */

		acpi_ut_delete_internal_object_list (internal_params);
	}

	return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_get_next_object
 *
 * PARAMETERS:  Type            - Type of object to be searched for
 *              Parent          - Parent object whose children we are getting
 *              Last_child      - Previous child that was found.
 *                                The NEXT child will be returned
 *              Ret_handle      - Where handle to the next object is placed
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Return the next peer object within the namespace.  If Handle is
 *              valid, Scope is ignored.  Otherwise, the first object within
 *              Scope is returned.
 *
 ******************************************************************************/

acpi_status
acpi_get_next_object (
	acpi_object_type        type,
	acpi_handle             parent,
	acpi_handle             child,
	acpi_handle             *ret_handle)
{
	acpi_status             status = AE_OK;
	acpi_namespace_node     *node;
	acpi_namespace_node     *parent_node = NULL;
	acpi_namespace_node     *child_node = NULL;


	/* Parameter validation */

	if (type > ACPI_TYPE_MAX) {
		return (AE_BAD_PARAMETER);
	}

	acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);

	/* If null handle, use the parent */

	if (!child) {
		/* Start search at the beginning of the specified scope */

		parent_node = acpi_ns_map_handle_to_node (parent);
		if (!parent_node) {
			status = AE_BAD_PARAMETER;
			goto unlock_and_exit;
		}
	}

	/* Non-null handle, ignore the parent */

	else {
		/* Convert and validate the handle */

		child_node = acpi_ns_map_handle_to_node (child);
		if (!child_node) {
			status = AE_BAD_PARAMETER;
			goto unlock_and_exit;
		}
	}


	/* Internal function does the real work */

	node = acpi_ns_get_next_node ((acpi_object_type8) type,
			   parent_node, child_node);
	if (!node) {
		status = AE_NOT_FOUND;
		goto unlock_and_exit;
	}

	if (ret_handle) {
		*ret_handle = acpi_ns_convert_entry_to_handle (node);
	}


unlock_and_exit:

	acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
	return (status);
}