drivers/acpi/namespace/nsnames.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsnames - Name manipulation and search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2005, 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 /* Local prototypes */
  52 static void
  53 acpi_ns_build_external_path(struct acpi_namespace_node *node,
  54                             acpi_size size, char *name_buffer);
  55
  56 /*******************************************************************************
  57  *
  58  * FUNCTION:    acpi_ns_build_external_path
  59  *
  60  * PARAMETERS:  Node            - NS node whose pathname is needed
  61  *              Size            - Size of the pathname
  62  *              *name_buffer    - Where to return the pathname
  63  *
  64  * RETURN:      Places the pathname into the name_buffer, in external format
  65  *              (name segments separated by path separators)
  66  *
  67  * DESCRIPTION: Generate a full pathaname
  68  *
  69  ******************************************************************************/
  70
  71 static void
  72 acpi_ns_build_external_path(struct acpi_namespace_node *node,
  73                             acpi_size size, char *name_buffer)
  74 {
  75         acpi_size index;
  76         struct acpi_namespace_node *parent_node;
  77
  78         ACPI_FUNCTION_NAME("ns_build_external_path");
  79
  80         /* Special case for root */
  81
  82         index = size - 1;
  83         if (index < ACPI_NAME_SIZE) {
  84                 name_buffer[0] = AML_ROOT_PREFIX;
  85                 name_buffer[1] = 0;
  86                 return;
  87         }
  88
  89         /* Store terminator byte, then build name backwards */
  90
  91         parent_node = node;
  92         name_buffer[index] = 0;
  93
  94         while ((index > ACPI_NAME_SIZE) && (parent_node != acpi_gbl_root_node)) {
  95                 index -= ACPI_NAME_SIZE;
  96
  97                 /* Put the name into the buffer */
  98
  99                 ACPI_MOVE_32_TO_32((name_buffer + index), &parent_node->name);
 100                 parent_node = acpi_ns_get_parent_node(parent_node);
 101
 102                 /* Prefix name with the path separator */
 103
 104                 index--;
 105                 name_buffer[index] = ACPI_PATH_SEPARATOR;
 106         }
 107
 108         /* Overwrite final separator with the root prefix character */
 109
 110         name_buffer[index] = AML_ROOT_PREFIX;
 111
 112         if (index != 0) {
 113                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 114                                   "Could not construct pathname; index=%X, size=%X, Path=%s\n",
 115                                   (u32) index, (u32) size, &name_buffer[size]));
 116         }
 117
 118         return;
 119 }
 120
 121 #ifdef ACPI_DEBUG_OUTPUT
 122 /*******************************************************************************
 123  *
 124  * FUNCTION:    acpi_ns_get_external_pathname
 125  *
 126  * PARAMETERS:  Node            - Namespace node whose pathname is needed
 127  *
 128  * RETURN:      Pointer to storage containing the fully qualified name of
 129  *              the node, In external format (name segments separated by path
 130  *              separators.)
 131  *
 132  * DESCRIPTION: Used for debug printing in acpi_ns_search_table().
 133  *
 134  ******************************************************************************/
 135
 136 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
 137 {
 138         char *name_buffer;
 139         acpi_size size;
 140
 141         ACPI_FUNCTION_TRACE_PTR("ns_get_external_pathname", node);
 142
 143         /* Calculate required buffer size based on depth below root */
 144
 145         size = acpi_ns_get_pathname_length(node);
 146
 147         /* Allocate a buffer to be returned to caller */
 148
 149         name_buffer = ACPI_MEM_CALLOCATE(size);
 150         if (!name_buffer) {
 151                 ACPI_REPORT_ERROR(("ns_get_table_pathname: allocation failure\n"));
 152                 return_PTR(NULL);
 153         }
 154
 155         /* Build the path in the allocated buffer */
 156
 157         acpi_ns_build_external_path(node, size, name_buffer);
 158         return_PTR(name_buffer);
 159 }
 160 #endif
 161
 162 /*******************************************************************************
 163  *
 164  * FUNCTION:    acpi_ns_get_pathname_length
 165  *
 166  * PARAMETERS:  Node        - Namespace node
 167  *
 168  * RETURN:      Length of path, including prefix
 169  *
 170  * DESCRIPTION: Get the length of the pathname string for this node
 171  *
 172  ******************************************************************************/
 173
 174 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
 175 {
 176         acpi_size size;
 177         struct acpi_namespace_node *next_node;
 178
 179         ACPI_FUNCTION_ENTRY();
 180
 181         /*
 182          * Compute length of pathname as 5 * number of name segments.
 183          * Go back up the parent tree to the root
 184          */
 185         size = 0;
 186         next_node = node;
 187
 188         while (next_node && (next_node != acpi_gbl_root_node)) {
 189                 size += ACPI_PATH_SEGMENT_LENGTH;
 190                 next_node = acpi_ns_get_parent_node(next_node);
 191         }
 192
 193         if (!size) {
 194                 size = 1;       /* Root node case */
 195         }
 196
 197         return (size + 1);      /* +1 for null string terminator */
 198 }
 199
 200 /*******************************************************************************
 201  *
 202  * FUNCTION:    acpi_ns_handle_to_pathname
 203  *
 204  * PARAMETERS:  target_handle           - Handle of named object whose name is
 205  *                                        to be found
 206  *              Buffer                  - Where the pathname is returned
 207  *
 208  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 209  *
 210  * DESCRIPTION: Build and return a full namespace pathname
 211  *
 212  ******************************************************************************/
 213
 214 acpi_status
 215 acpi_ns_handle_to_pathname(acpi_handle target_handle,
 216                            struct acpi_buffer * buffer)
 217 {
 218         acpi_status status;
 219         struct acpi_namespace_node *node;
 220         acpi_size required_size;
 221
 222         ACPI_FUNCTION_TRACE_PTR("ns_handle_to_pathname", target_handle);
 223
 224         node = acpi_ns_map_handle_to_node(target_handle);
 225         if (!node) {
 226                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 227         }
 228
 229         /* Determine size required for the caller buffer */
 230
 231         required_size = acpi_ns_get_pathname_length(node);
 232
 233         /* Validate/Allocate/Clear caller buffer */
 234
 235         status = acpi_ut_initialize_buffer(buffer, required_size);
 236         if (ACPI_FAILURE(status)) {
 237                 return_ACPI_STATUS(status);
 238         }
 239
 240         /* Build the path in the caller buffer */
 241
 242         acpi_ns_build_external_path(node, required_size, buffer->pointer);
 243
 244         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
 245                           (char *)buffer->pointer, (u32) required_size));
 246         return_ACPI_STATUS(AE_OK);
 247 }