drivers/acpi/acpica/nsnames.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsnames - Name manipulation and search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2012, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include "accommon.h"
  46 #include "amlcode.h"
  47 #include "acnamesp.h"
  48
  49 #define _COMPONENT          ACPI_NAMESPACE
  50 ACPI_MODULE_NAME("nsnames")
  51
  52 /*******************************************************************************
  53  *
  54  * FUNCTION:    acpi_ns_build_external_path
  55  *
  56  * PARAMETERS:  Node            - NS node whose pathname is needed
  57  *              Size            - Size of the pathname
  58  *              *name_buffer    - Where to return the pathname
  59  *
  60  * RETURN:      Status
  61  *              Places the pathname into the name_buffer, in external format
  62  *              (name segments separated by path separators)
  63  *
  64  * DESCRIPTION: Generate a full pathaname
  65  *
  66  ******************************************************************************/
  67 acpi_status
  68 acpi_ns_build_external_path(struct acpi_namespace_node *node,
  69                             acpi_size size, char *name_buffer)
  70 {
  71         acpi_size index;
  72         struct acpi_namespace_node *parent_node;
  73
  74         ACPI_FUNCTION_ENTRY();
  75
  76         /* Special case for root */
  77
  78         index = size - 1;
  79         if (index < ACPI_NAME_SIZE) {
  80                 name_buffer[0] = AML_ROOT_PREFIX;
  81                 name_buffer[1] = 0;
  82                 return (AE_OK);
  83         }
  84
  85         /* Store terminator byte, then build name backwards */
  86
  87         parent_node = node;
  88         name_buffer[index] = 0;
  89
  90         while ((index > ACPI_NAME_SIZE) && (parent_node != acpi_gbl_root_node)) {
  91                 index -= ACPI_NAME_SIZE;
  92
  93                 /* Put the name into the buffer */
  94
  95                 ACPI_MOVE_32_TO_32((name_buffer + index), &parent_node->name);
  96                 parent_node = parent_node->parent;
  97
  98                 /* Prefix name with the path separator */
  99
 100                 index--;
 101                 name_buffer[index] = ACPI_PATH_SEPARATOR;
 102         }
 103
 104         /* Overwrite final separator with the root prefix character */
 105
 106         name_buffer[index] = AML_ROOT_PREFIX;
 107
 108         if (index != 0) {
 109                 ACPI_ERROR((AE_INFO,
 110                             "Could not construct external pathname; index=%u, size=%u, Path=%s",
 111                             (u32) index, (u32) size, &name_buffer[size]));
 112
 113                 return (AE_BAD_PARAMETER);
 114         }
 115
 116         return (AE_OK);
 117 }
 118
 119 /*******************************************************************************
 120  *
 121  * FUNCTION:    acpi_ns_get_external_pathname
 122  *
 123  * PARAMETERS:  Node            - Namespace node whose pathname is needed
 124  *
 125  * RETURN:      Pointer to storage containing the fully qualified name of
 126  *              the node, In external format (name segments separated by path
 127  *              separators.)
 128  *
 129  * DESCRIPTION: Used for debug printing in acpi_ns_search_table().
 130  *
 131  ******************************************************************************/
 132
 133 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
 134 {
 135         acpi_status status;
 136         char *name_buffer;
 137         acpi_size size;
 138
 139         ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);
 140
 141         /* Calculate required buffer size based on depth below root */
 142
 143         size = acpi_ns_get_pathname_length(node);
 144         if (!size) {
 145                 return_PTR(NULL);
 146         }
 147
 148         /* Allocate a buffer to be returned to caller */
 149
 150         name_buffer = ACPI_ALLOCATE_ZEROED(size);
 151         if (!name_buffer) {
 152                 ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
 153                 return_PTR(NULL);
 154         }
 155
 156         /* Build the path in the allocated buffer */
 157
 158         status = acpi_ns_build_external_path(node, size, name_buffer);
 159         if (ACPI_FAILURE(status)) {
 160                 ACPI_FREE(name_buffer);
 161                 return_PTR(NULL);
 162         }
 163
 164         return_PTR(name_buffer);
 165 }
 166
 167 /*******************************************************************************
 168  *
 169  * FUNCTION:    acpi_ns_get_pathname_length
 170  *
 171  * PARAMETERS:  Node        - Namespace node
 172  *
 173  * RETURN:      Length of path, including prefix
 174  *
 175  * DESCRIPTION: Get the length of the pathname string for this node
 176  *
 177  ******************************************************************************/
 178
 179 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
 180 {
 181         acpi_size size;
 182         struct acpi_namespace_node *next_node;
 183
 184         ACPI_FUNCTION_ENTRY();
 185
 186         /*
 187          * Compute length of pathname as 5 * number of name segments.
 188          * Go back up the parent tree to the root
 189          */
 190         size = 0;
 191         next_node = node;
 192
 193         while (next_node && (next_node != acpi_gbl_root_node)) {
 194                 if (ACPI_GET_DESCRIPTOR_TYPE(next_node) != ACPI_DESC_TYPE_NAMED) {
 195                         ACPI_ERROR((AE_INFO,
 196                                     "Invalid Namespace Node (%p) while traversing namespace",
 197                                     next_node));
 198                         return 0;
 199                 }
 200                 size += ACPI_PATH_SEGMENT_LENGTH;
 201                 next_node = next_node->parent;
 202         }
 203
 204         if (!size) {
 205                 size = 1;       /* Root node case */
 206         }
 207
 208         return (size + 1);      /* +1 for null string terminator */
 209 }
 210
 211 /*******************************************************************************
 212  *
 213  * FUNCTION:    acpi_ns_handle_to_pathname
 214  *
 215  * PARAMETERS:  target_handle           - Handle of named object whose name is
 216  *                                        to be found
 217  *              Buffer                  - Where the pathname is returned
 218  *
 219  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 220  *
 221  * DESCRIPTION: Build and return a full namespace pathname
 222  *
 223  ******************************************************************************/
 224
 225 acpi_status
 226 acpi_ns_handle_to_pathname(acpi_handle target_handle,
 227                            struct acpi_buffer * buffer)
 228 {
 229         acpi_status status;
 230         struct acpi_namespace_node *node;
 231         acpi_size required_size;
 232
 233         ACPI_FUNCTION_TRACE_PTR(ns_handle_to_pathname, target_handle);
 234
 235         node = acpi_ns_validate_handle(target_handle);
 236         if (!node) {
 237                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 238         }
 239
 240         /* Determine size required for the caller buffer */
 241
 242         required_size = acpi_ns_get_pathname_length(node);
 243         if (!required_size) {
 244                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 245         }
 246
 247         /* Validate/Allocate/Clear caller buffer */
 248
 249         status = acpi_ut_initialize_buffer(buffer, required_size);
 250         if (ACPI_FAILURE(status)) {
 251                 return_ACPI_STATUS(status);
 252         }
 253
 254         /* Build the path in the caller buffer */
 255
 256         status =
 257             acpi_ns_build_external_path(node, required_size, buffer->pointer);
 258         if (ACPI_FAILURE(status)) {
 259                 return_ACPI_STATUS(status);
 260         }
 261
 262         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
 263                           (char *)buffer->pointer, (u32) required_size));
 264         return_ACPI_STATUS(AE_OK);
 265 }