drivers/acpi/acpica/nsnames.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsnames - Name manipulation and search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2013, 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 to obtain the full pathname to a namespace node, usually
 130  *              for error and debug statements.
 131  *
 132  ******************************************************************************/
 133
 134 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
 135 {
 136         acpi_status status;
 137         char *name_buffer;
 138         acpi_size size;
 139
 140         ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);
 141
 142         /* Calculate required buffer size based on depth below root */
 143
 144         size = acpi_ns_get_pathname_length(node);
 145         if (!size) {
 146                 return_PTR(NULL);
 147         }
 148
 149         /* Allocate a buffer to be returned to caller */
 150
 151         name_buffer = ACPI_ALLOCATE_ZEROED(size);
 152         if (!name_buffer) {
 153                 ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
 154                 return_PTR(NULL);
 155         }
 156
 157         /* Build the path in the allocated buffer */
 158
 159         status = acpi_ns_build_external_path(node, size, name_buffer);
 160         if (ACPI_FAILURE(status)) {
 161                 ACPI_FREE(name_buffer);
 162                 return_PTR(NULL);
 163         }
 164
 165         return_PTR(name_buffer);
 166 }
 167
 168 /*******************************************************************************
 169  *
 170  * FUNCTION:    acpi_ns_get_pathname_length
 171  *
 172  * PARAMETERS:  node        - Namespace node
 173  *
 174  * RETURN:      Length of path, including prefix
 175  *
 176  * DESCRIPTION: Get the length of the pathname string for this node
 177  *
 178  ******************************************************************************/
 179
 180 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
 181 {
 182         acpi_size size;
 183         struct acpi_namespace_node *next_node;
 184
 185         ACPI_FUNCTION_ENTRY();
 186
 187         /*
 188          * Compute length of pathname as 5 * number of name segments.
 189          * Go back up the parent tree to the root
 190          */
 191         size = 0;
 192         next_node = node;
 193
 194         while (next_node && (next_node != acpi_gbl_root_node)) {
 195                 if (ACPI_GET_DESCRIPTOR_TYPE(next_node) != ACPI_DESC_TYPE_NAMED) {
 196                         ACPI_ERROR((AE_INFO,
 197                                     "Invalid Namespace Node (%p) while traversing namespace",
 198                                     next_node));
 199                         return (0);
 200                 }
 201                 size += ACPI_PATH_SEGMENT_LENGTH;
 202                 next_node = next_node->parent;
 203         }
 204
 205         if (!size) {
 206                 size = 1;       /* Root node case */
 207         }
 208
 209         return (size + 1);      /* +1 for null string terminator */
 210 }
 211
 212 /*******************************************************************************
 213  *
 214  * FUNCTION:    acpi_ns_handle_to_pathname
 215  *
 216  * PARAMETERS:  target_handle           - Handle of named object whose name is
 217  *                                        to be found
 218  *              buffer                  - Where the pathname is returned
 219  *
 220  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 221  *
 222  * DESCRIPTION: Build and return a full namespace pathname
 223  *
 224  ******************************************************************************/
 225
 226 acpi_status
 227 acpi_ns_handle_to_pathname(acpi_handle target_handle,
 228                            struct acpi_buffer * buffer)
 229 {
 230         acpi_status status;
 231         struct acpi_namespace_node *node;
 232         acpi_size required_size;
 233
 234         ACPI_FUNCTION_TRACE_PTR(ns_handle_to_pathname, target_handle);
 235
 236         node = acpi_ns_validate_handle(target_handle);
 237         if (!node) {
 238                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 239         }
 240
 241         /* Determine size required for the caller buffer */
 242
 243         required_size = acpi_ns_get_pathname_length(node);
 244         if (!required_size) {
 245                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 246         }
 247
 248         /* Validate/Allocate/Clear caller buffer */
 249
 250         status = acpi_ut_initialize_buffer(buffer, required_size);
 251         if (ACPI_FAILURE(status)) {
 252                 return_ACPI_STATUS(status);
 253         }
 254
 255         /* Build the path in the caller buffer */
 256
 257         status =
 258             acpi_ns_build_external_path(node, required_size, buffer->pointer);
 259         if (ACPI_FAILURE(status)) {
 260                 return_ACPI_STATUS(status);
 261         }
 262
 263         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
 264                           (char *)buffer->pointer, (u32) required_size));
 265         return_ACPI_STATUS(AE_OK);
 266 }