drivers/acpi/namespace/nsnames.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsnames - Name manipulation and search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2008, 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 <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:      Status
  60  *              Places the pathname into the name_buffer, in external format
  61  *              (name segments separated by path separators)
  62  *
  63  * DESCRIPTION: Generate a full pathaname
  64  *
  65  ******************************************************************************/
  66 acpi_status
  67 acpi_ns_build_external_path(struct acpi_namespace_node *node,
  68                             acpi_size size, char *name_buffer)
  69 {
  70         acpi_size index;
  71         struct acpi_namespace_node *parent_node;
  72
  73         ACPI_FUNCTION_ENTRY();
  74
  75         /* Special case for root */
  76
  77         index = size - 1;
  78         if (index < ACPI_NAME_SIZE) {
  79                 name_buffer[0] = AML_ROOT_PREFIX;
  80                 name_buffer[1] = 0;
  81                 return (AE_OK);
  82         }
  83
  84         /* Store terminator byte, then build name backwards */
  85
  86         parent_node = node;
  87         name_buffer[index] = 0;
  88
  89         while ((index > ACPI_NAME_SIZE) && (parent_node != acpi_gbl_root_node)) {
  90                 index -= ACPI_NAME_SIZE;
  91
  92                 /* Put the name into the buffer */
  93
  94                 ACPI_MOVE_32_TO_32((name_buffer + index), &parent_node->name);
  95                 parent_node = acpi_ns_get_parent_node(parent_node);
  96
  97                 /* Prefix name with the path separator */
  98
  99                 index--;
 100                 name_buffer[index] = ACPI_PATH_SEPARATOR;
 101         }
 102
 103         /* Overwrite final separator with the root prefix character */
 104
 105         name_buffer[index] = AML_ROOT_PREFIX;
 106
 107         if (index != 0) {
 108                 ACPI_ERROR((AE_INFO,
 109                             "Could not construct external pathname; index=%X, size=%X, Path=%s",
 110                             (u32) index, (u32) size, &name_buffer[size]));
 111
 112                 return (AE_BAD_PARAMETER);
 113         }
 114
 115         return (AE_OK);
 116 }
 117
 118 /*******************************************************************************
 119  *
 120  * FUNCTION:    acpi_ns_get_external_pathname
 121  *
 122  * PARAMETERS:  Node            - Namespace node whose pathname is needed
 123  *
 124  * RETURN:      Pointer to storage containing the fully qualified name of
 125  *              the node, In external format (name segments separated by path
 126  *              separators.)
 127  *
 128  * DESCRIPTION: Used for debug printing in acpi_ns_search_table().
 129  *
 130  ******************************************************************************/
 131
 132 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
 133 {
 134         acpi_status status;
 135         char *name_buffer;
 136         acpi_size size;
 137
 138         ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);
 139
 140         /* Calculate required buffer size based on depth below root */
 141
 142         size = acpi_ns_get_pathname_length(node);
 143         if (!size) {
 144                 return_PTR(NULL);
 145         }
 146
 147         /* Allocate a buffer to be returned to caller */
 148
 149         name_buffer = ACPI_ALLOCATE_ZEROED(size);
 150         if (!name_buffer) {
 151                 ACPI_ERROR((AE_INFO, "Allocation failure"));
 152                 return_PTR(NULL);
 153         }
 154
 155         /* Build the path in the allocated buffer */
 156
 157         status = acpi_ns_build_external_path(node, size, name_buffer);
 158         if (ACPI_FAILURE(status)) {
 159                 ACPI_FREE(name_buffer);
 160                 return_PTR(NULL);
 161         }
 162
 163         return_PTR(name_buffer);
 164 }
 165
 166 /*******************************************************************************
 167  *
 168  * FUNCTION:    acpi_ns_get_pathname_length
 169  *
 170  * PARAMETERS:  Node        - Namespace node
 171  *
 172  * RETURN:      Length of path, including prefix
 173  *
 174  * DESCRIPTION: Get the length of the pathname string for this node
 175  *
 176  ******************************************************************************/
 177
 178 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
 179 {
 180         acpi_size size;
 181         struct acpi_namespace_node *next_node;
 182
 183         ACPI_FUNCTION_ENTRY();
 184
 185         /*
 186          * Compute length of pathname as 5 * number of name segments.
 187          * Go back up the parent tree to the root
 188          */
 189         size = 0;
 190         next_node = node;
 191
 192         while (next_node && (next_node != acpi_gbl_root_node)) {
 193                 if (ACPI_GET_DESCRIPTOR_TYPE(next_node) != ACPI_DESC_TYPE_NAMED) {
 194                         ACPI_ERROR((AE_INFO,
 195                                     "Invalid Namespace Node (%p) while traversing namespace",
 196                                     next_node));
 197                         return 0;
 198                 }
 199                 size += ACPI_PATH_SEGMENT_LENGTH;
 200                 next_node = acpi_ns_get_parent_node(next_node);
 201         }
 202
 203         if (!size) {
 204                 size = 1;       /* Root node case */
 205         }
 206
 207         return (size + 1);      /* +1 for null string terminator */
 208 }
 209
 210 /*******************************************************************************
 211  *
 212  * FUNCTION:    acpi_ns_handle_to_pathname
 213  *
 214  * PARAMETERS:  target_handle           - Handle of named object whose name is
 215  *                                        to be found
 216  *              Buffer                  - Where the pathname is returned
 217  *
 218  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 219  *
 220  * DESCRIPTION: Build and return a full namespace pathname
 221  *
 222  ******************************************************************************/
 223
 224 acpi_status
 225 acpi_ns_handle_to_pathname(acpi_handle target_handle,
 226                            struct acpi_buffer * buffer)
 227 {
 228         acpi_status status;
 229         struct acpi_namespace_node *node;
 230         acpi_size required_size;
 231
 232         ACPI_FUNCTION_TRACE_PTR(ns_handle_to_pathname, target_handle);
 233
 234         node = acpi_ns_map_handle_to_node(target_handle);
 235         if (!node) {
 236                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 237         }
 238
 239         /* Determine size required for the caller buffer */
 240
 241         required_size = acpi_ns_get_pathname_length(node);
 242         if (!required_size) {
 243                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 244         }
 245
 246         /* Validate/Allocate/Clear caller buffer */
 247
 248         status = acpi_ut_initialize_buffer(buffer, required_size);
 249         if (ACPI_FAILURE(status)) {
 250                 return_ACPI_STATUS(status);
 251         }
 252
 253         /* Build the path in the caller buffer */
 254
 255         status =
 256             acpi_ns_build_external_path(node, required_size, buffer->pointer);
 257         if (ACPI_FAILURE(status)) {
 258                 return_ACPI_STATUS(status);
 259         }
 260
 261         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
 262                           (char *)buffer->pointer, (u32) required_size));
 263         return_ACPI_STATUS(AE_OK);
 264 }