drivers/acpi/namespace/nsnames.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsnames - Name manipulation and search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2007, R. Byron Moore
   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 <acpi/amlcode.h>
  46 #include <acpi/acnamesp.h>
  47
  48 #define _COMPONENT          ACPI_NAMESPACE
  49 ACPI_MODULE_NAME("nsnames")
  50
  51 /*******************************************************************************
  52  *
  53  * FUNCTION:    acpi_ns_build_external_path
  54  *
  55  * PARAMETERS:  Node            - NS node whose pathname is needed
  56  *              Size            - Size of the pathname
  57  *              *name_buffer    - Where to return the pathname
  58  *
  59  * RETURN:      Places the pathname into the name_buffer, in external format
  60  *              (name segments separated by path separators)
  61  *
  62  * DESCRIPTION: Generate a full pathaname
  63  *
  64  ******************************************************************************/
  65 void
  66 acpi_ns_build_external_path(struct acpi_namespace_node *node,
  67                             acpi_size size, char *name_buffer)
  68 {
  69         acpi_size index;
  70         struct acpi_namespace_node *parent_node;
  71
  72         ACPI_FUNCTION_ENTRY();
  73
  74         /* Special case for root */
  75
  76         index = size - 1;
  77         if (index < ACPI_NAME_SIZE) {
  78                 name_buffer[0] = AML_ROOT_PREFIX;
  79                 name_buffer[1] = 0;
  80                 return;
  81         }
  82
  83         /* Store terminator byte, then build name backwards */
  84
  85         parent_node = node;
  86         name_buffer[index] = 0;
  87
  88         while ((index > ACPI_NAME_SIZE) && (parent_node != acpi_gbl_root_node)) {
  89                 index -= ACPI_NAME_SIZE;
  90
  91                 /* Put the name into the buffer */
  92
  93                 ACPI_MOVE_32_TO_32((name_buffer + index), &parent_node->name);
  94                 parent_node = acpi_ns_get_parent_node(parent_node);
  95
  96                 /* Prefix name with the path separator */
  97
  98                 index--;
  99                 name_buffer[index] = ACPI_PATH_SEPARATOR;
 100         }
 101
 102         /* Overwrite final separator with the root prefix character */
 103
 104         name_buffer[index] = AML_ROOT_PREFIX;
 105
 106         if (index != 0) {
 107                 ACPI_ERROR((AE_INFO,
 108                             "Could not construct pathname; index=%X, size=%X, Path=%s",
 109                             (u32) index, (u32) size, &name_buffer[size]));
 110         }
 111
 112         return;
 113 }
 114
 115 #ifdef ACPI_DEBUG_OUTPUT
 116 /*******************************************************************************
 117  *
 118  * FUNCTION:    acpi_ns_get_external_pathname
 119  *
 120  * PARAMETERS:  Node            - Namespace node whose pathname is needed
 121  *
 122  * RETURN:      Pointer to storage containing the fully qualified name of
 123  *              the node, In external format (name segments separated by path
 124  *              separators.)
 125  *
 126  * DESCRIPTION: Used for debug printing in acpi_ns_search_table().
 127  *
 128  ******************************************************************************/
 129
 130 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
 131 {
 132         char *name_buffer;
 133         acpi_size size;
 134
 135         ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);
 136
 137         /* Calculate required buffer size based on depth below root */
 138
 139         size = acpi_ns_get_pathname_length(node);
 140
 141         /* Allocate a buffer to be returned to caller */
 142
 143         name_buffer = ACPI_ALLOCATE_ZEROED(size);
 144         if (!name_buffer) {
 145                 ACPI_ERROR((AE_INFO, "Allocation failure"));
 146                 return_PTR(NULL);
 147         }
 148
 149         /* Build the path in the allocated buffer */
 150
 151         acpi_ns_build_external_path(node, size, name_buffer);
 152         return_PTR(name_buffer);
 153 }
 154 #endif
 155
 156 /*******************************************************************************
 157  *
 158  * FUNCTION:    acpi_ns_get_pathname_length
 159  *
 160  * PARAMETERS:  Node        - Namespace node
 161  *
 162  * RETURN:      Length of path, including prefix
 163  *
 164  * DESCRIPTION: Get the length of the pathname string for this node
 165  *
 166  ******************************************************************************/
 167
 168 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
 169 {
 170         acpi_size size;
 171         struct acpi_namespace_node *next_node;
 172
 173         ACPI_FUNCTION_ENTRY();
 174
 175         /*
 176          * Compute length of pathname as 5 * number of name segments.
 177          * Go back up the parent tree to the root
 178          */
 179         size = 0;
 180         next_node = node;
 181
 182         while (next_node && (next_node != acpi_gbl_root_node)) {
 183                 size += ACPI_PATH_SEGMENT_LENGTH;
 184                 next_node = acpi_ns_get_parent_node(next_node);
 185         }
 186
 187         if (!size) {
 188                 size = 1;       /* Root node case */
 189         }
 190
 191         return (size + 1);      /* +1 for null string terminator */
 192 }
 193
 194 /*******************************************************************************
 195  *
 196  * FUNCTION:    acpi_ns_handle_to_pathname
 197  *
 198  * PARAMETERS:  target_handle           - Handle of named object whose name is
 199  *                                        to be found
 200  *              Buffer                  - Where the pathname is returned
 201  *
 202  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 203  *
 204  * DESCRIPTION: Build and return a full namespace pathname
 205  *
 206  ******************************************************************************/
 207
 208 acpi_status
 209 acpi_ns_handle_to_pathname(acpi_handle target_handle,
 210                            struct acpi_buffer * buffer)
 211 {
 212         acpi_status status;
 213         struct acpi_namespace_node *node;
 214         acpi_size required_size;
 215
 216         ACPI_FUNCTION_TRACE_PTR(ns_handle_to_pathname, target_handle);
 217
 218         node = acpi_ns_map_handle_to_node(target_handle);
 219         if (!node) {
 220                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 221         }
 222
 223         /* Determine size required for the caller buffer */
 224
 225         required_size = acpi_ns_get_pathname_length(node);
 226
 227         /* Validate/Allocate/Clear caller buffer */
 228
 229         status = acpi_ut_initialize_buffer(buffer, required_size);
 230         if (ACPI_FAILURE(status)) {
 231                 return_ACPI_STATUS(status);
 232         }
 233
 234         /* Build the path in the caller buffer */
 235
 236         acpi_ns_build_external_path(node, required_size, buffer->pointer);
 237
 238         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
 239                           (char *)buffer->pointer, (u32) required_size));
 240         return_ACPI_STATUS(AE_OK);
 241 }