kernel/drivers/acpi/acpica/nsnames.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsnames - Name manipulation and search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2015, 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_get_external_pathname
  55  *
  56  * PARAMETERS:  node            - Namespace node whose pathname is needed
  57  *
  58  * RETURN:      Pointer to storage containing the fully qualified name of
  59  *              the node, In external format (name segments separated by path
  60  *              separators.)
  61  *
  62  * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
  63  *              for error and debug statements.
  64  *
  65  ******************************************************************************/
  66 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
  67 {
  68         char *name_buffer;
  69
  70         ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);
  71
  72         name_buffer = acpi_ns_get_normalized_pathname(node, FALSE);
  73
  74         return_PTR(name_buffer);
  75 }
  76
  77 /*******************************************************************************
  78  *
  79  * FUNCTION:    acpi_ns_get_pathname_length
  80  *
  81  * PARAMETERS:  node        - Namespace node
  82  *
  83  * RETURN:      Length of path, including prefix
  84  *
  85  * DESCRIPTION: Get the length of the pathname string for this node
  86  *
  87  ******************************************************************************/
  88
  89 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
  90 {
  91         acpi_size size;
  92
  93         ACPI_FUNCTION_ENTRY();
  94
  95         size = acpi_ns_build_normalized_path(node, NULL, 0, FALSE);
  96
  97         return (size);
  98 }
  99
 100 /*******************************************************************************
 101  *
 102  * FUNCTION:    acpi_ns_handle_to_pathname
 103  *
 104  * PARAMETERS:  target_handle           - Handle of named object whose name is
 105  *                                        to be found
 106  *              buffer                  - Where the pathname is returned
 107  *              no_trailing             - Remove trailing '_' for each name
 108  *                                        segment
 109  *
 110  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 111  *
 112  * DESCRIPTION: Build and return a full namespace pathname
 113  *
 114  ******************************************************************************/
 115
 116 acpi_status
 117 acpi_ns_handle_to_pathname(acpi_handle target_handle,
 118                            struct acpi_buffer * buffer, u8 no_trailing)
 119 {
 120         acpi_status status;
 121         struct acpi_namespace_node *node;
 122         acpi_size required_size;
 123
 124         ACPI_FUNCTION_TRACE_PTR(ns_handle_to_pathname, target_handle);
 125
 126         node = acpi_ns_validate_handle(target_handle);
 127         if (!node) {
 128                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 129         }
 130
 131         /* Determine size required for the caller buffer */
 132
 133         required_size =
 134             acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
 135         if (!required_size) {
 136                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 137         }
 138
 139         /* Validate/Allocate/Clear caller buffer */
 140
 141         status = acpi_ut_initialize_buffer(buffer, required_size);
 142         if (ACPI_FAILURE(status)) {
 143                 return_ACPI_STATUS(status);
 144         }
 145
 146         /* Build the path in the caller buffer */
 147
 148         (void)acpi_ns_build_normalized_path(node, buffer->pointer,
 149                                             required_size, no_trailing);
 150         if (ACPI_FAILURE(status)) {
 151                 return_ACPI_STATUS(status);
 152         }
 153
 154         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
 155                           (char *)buffer->pointer, (u32) required_size));
 156         return_ACPI_STATUS(AE_OK);
 157 }
 158
 159 /*******************************************************************************
 160  *
 161  * FUNCTION:    acpi_ns_build_normalized_path
 162  *
 163  * PARAMETERS:  node        - Namespace node
 164  *              full_path   - Where the path name is returned
 165  *              path_size   - Size of returned path name buffer
 166  *              no_trailing - Remove trailing '_' from each name segment
 167  *
 168  * RETURN:      Return 1 if the AML path is empty, otherwise returning (length
 169  *              of pathname + 1) which means the 'FullPath' contains a trailing
 170  *              null.
 171  *
 172  * DESCRIPTION: Build and return a full namespace pathname.
 173  *              Note that if the size of 'FullPath' isn't large enough to
 174  *              contain the namespace node's path name, the actual required
 175  *              buffer length is returned, and it should be greater than
 176  *              'PathSize'. So callers are able to check the returning value
 177  *              to determine the buffer size of 'FullPath'.
 178  *
 179  ******************************************************************************/
 180
 181 u32
 182 acpi_ns_build_normalized_path(struct acpi_namespace_node *node,
 183                               char *full_path, u32 path_size, u8 no_trailing)
 184 {
 185         u32 length = 0, i;
 186         char name[ACPI_NAME_SIZE];
 187         u8 do_no_trailing;
 188         char c, *left, *right;
 189         struct acpi_namespace_node *next_node;
 190
 191         ACPI_FUNCTION_TRACE_PTR(ns_build_normalized_path, node);
 192
 193 #define ACPI_PATH_PUT8(path, size, byte, length)    \
 194         do {                                            \
 195                 if ((length) < (size))                      \
 196                 {                                           \
 197                         (path)[(length)] = (byte);              \
 198                 }                                           \
 199                 (length)++;                                 \
 200         } while (0)
 201
 202         /*
 203          * Make sure the path_size is correct, so that we don't need to
 204          * validate both full_path and path_size.
 205          */
 206         if (!full_path) {
 207                 path_size = 0;
 208         }
 209
 210         if (!node) {
 211                 goto build_trailing_null;
 212         }
 213
 214         next_node = node;
 215         while (next_node && next_node != acpi_gbl_root_node) {
 216                 if (next_node != node) {
 217                         ACPI_PATH_PUT8(full_path, path_size,
 218                                        AML_DUAL_NAME_PREFIX, length);
 219                 }
 220                 ACPI_MOVE_32_TO_32(name, &next_node->name);
 221                 do_no_trailing = no_trailing;
 222                 for (i = 0; i < 4; i++) {
 223                         c = name[4 - i - 1];
 224                         if (do_no_trailing && c != '_') {
 225                                 do_no_trailing = FALSE;
 226                         }
 227                         if (!do_no_trailing) {
 228                                 ACPI_PATH_PUT8(full_path, path_size, c, length);
 229                         }
 230                 }
 231                 next_node = next_node->parent;
 232         }
 233         ACPI_PATH_PUT8(full_path, path_size, AML_ROOT_PREFIX, length);
 234
 235         /* Reverse the path string */
 236
 237         if (length <= path_size) {
 238                 left = full_path;
 239                 right = full_path + length - 1;
 240                 while (left < right) {
 241                         c = *left;
 242                         *left++ = *right;
 243                         *right-- = c;
 244                 }
 245         }
 246
 247         /* Append the trailing null */
 248
 249 build_trailing_null:
 250         ACPI_PATH_PUT8(full_path, path_size, '\0', length);
 251
 252 #undef ACPI_PATH_PUT8
 253
 254         return_UINT32(length);
 255 }
 256
 257 /*******************************************************************************
 258  *
 259  * FUNCTION:    acpi_ns_get_normalized_pathname
 260  *
 261  * PARAMETERS:  node            - Namespace node whose pathname is needed
 262  *              no_trailing     - Remove trailing '_' from each name segment
 263  *
 264  * RETURN:      Pointer to storage containing the fully qualified name of
 265  *              the node, In external format (name segments separated by path
 266  *              separators.)
 267  *
 268  * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
 269  *              for error and debug statements. All trailing '_' will be
 270  *              removed from the full pathname if 'NoTrailing' is specified..
 271  *
 272  ******************************************************************************/
 273
 274 char *acpi_ns_get_normalized_pathname(struct acpi_namespace_node *node,
 275                                       u8 no_trailing)
 276 {
 277         char *name_buffer;
 278         acpi_size size;
 279
 280         ACPI_FUNCTION_TRACE_PTR(ns_get_normalized_pathname, node);
 281
 282         /* Calculate required buffer size based on depth below root */
 283
 284         size = acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
 285         if (!size) {
 286                 return_PTR(NULL);
 287         }
 288
 289         /* Allocate a buffer to be returned to caller */
 290
 291         name_buffer = ACPI_ALLOCATE_ZEROED(size);
 292         if (!name_buffer) {
 293                 ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
 294                 return_PTR(NULL);
 295         }
 296
 297         /* Build the path in the allocated buffer */
 298
 299         (void)acpi_ns_build_normalized_path(node, name_buffer, size,
 300                                             no_trailing);
 301
 302         return_PTR(name_buffer);
 303 }