drivers/acpi/namespace/nsnames.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsnames - Name manipulation and search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2006, 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_ENTRY();
  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_REPORT_ERROR(("Could not construct pathname; index=%X, size=%X, Path=%s\n", (u32) index, (u32) size, &name_buffer[size]));
 114         }
 115
 116         return;
 117 }
 118
 119 #ifdef ACPI_DEBUG_OUTPUT
 120 /*******************************************************************************
 121  *
 122  * FUNCTION:    acpi_ns_get_external_pathname
 123  *
 124  * PARAMETERS:  Node            - Namespace node whose pathname is needed
 125  *
 126  * RETURN:      Pointer to storage containing the fully qualified name of
 127  *              the node, In external format (name segments separated by path
 128  *              separators.)
 129  *
 130  * DESCRIPTION: Used for debug printing in acpi_ns_search_table().
 131  *
 132  ******************************************************************************/
 133
 134 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
 135 {
 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
 145         /* Allocate a buffer to be returned to caller */
 146
 147         name_buffer = ACPI_MEM_CALLOCATE(size);
 148         if (!name_buffer) {
 149                 ACPI_REPORT_ERROR(("Allocation failure\n"));
 150                 return_PTR(NULL);
 151         }
 152
 153         /* Build the path in the allocated buffer */
 154
 155         acpi_ns_build_external_path(node, size, name_buffer);
 156         return_PTR(name_buffer);
 157 }
 158 #endif
 159
 160 /*******************************************************************************
 161  *
 162  * FUNCTION:    acpi_ns_get_pathname_length
 163  *
 164  * PARAMETERS:  Node        - Namespace node
 165  *
 166  * RETURN:      Length of path, including prefix
 167  *
 168  * DESCRIPTION: Get the length of the pathname string for this node
 169  *
 170  ******************************************************************************/
 171
 172 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
 173 {
 174         acpi_size size;
 175         struct acpi_namespace_node *next_node;
 176
 177         ACPI_FUNCTION_ENTRY();
 178
 179         /*
 180          * Compute length of pathname as 5 * number of name segments.
 181          * Go back up the parent tree to the root
 182          */
 183         size = 0;
 184         next_node = node;
 185
 186         while (next_node && (next_node != acpi_gbl_root_node)) {
 187                 size += ACPI_PATH_SEGMENT_LENGTH;
 188                 next_node = acpi_ns_get_parent_node(next_node);
 189         }
 190
 191         if (!size) {
 192                 size = 1;       /* Root node case */
 193         }
 194
 195         return (size + 1);      /* +1 for null string terminator */
 196 }
 197
 198 /*******************************************************************************
 199  *
 200  * FUNCTION:    acpi_ns_handle_to_pathname
 201  *
 202  * PARAMETERS:  target_handle           - Handle of named object whose name is
 203  *                                        to be found
 204  *              Buffer                  - Where the pathname is returned
 205  *
 206  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 207  *
 208  * DESCRIPTION: Build and return a full namespace pathname
 209  *
 210  ******************************************************************************/
 211
 212 acpi_status
 213 acpi_ns_handle_to_pathname(acpi_handle target_handle,
 214                            struct acpi_buffer * buffer)
 215 {
 216         acpi_status status;
 217         struct acpi_namespace_node *node;
 218         acpi_size required_size;
 219
 220         ACPI_FUNCTION_TRACE_PTR("ns_handle_to_pathname", target_handle);
 221
 222         node = acpi_ns_map_handle_to_node(target_handle);
 223         if (!node) {
 224                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 225         }
 226
 227         /* Determine size required for the caller buffer */
 228
 229         required_size = acpi_ns_get_pathname_length(node);
 230
 231         /* Validate/Allocate/Clear caller buffer */
 232
 233         status = acpi_ut_initialize_buffer(buffer, required_size);
 234         if (ACPI_FAILURE(status)) {
 235                 return_ACPI_STATUS(status);
 236         }
 237
 238         /* Build the path in the caller buffer */
 239
 240         acpi_ns_build_external_path(node, required_size, buffer->pointer);
 241
 242         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
 243                           (char *)buffer->pointer, (u32) required_size));
 244         return_ACPI_STATUS(AE_OK);
 245 }