drivers/acpi/acpica/nsnames.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsnames - Name manipulation and search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2016, 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         return_PTR(name_buffer);
  74 }
  75
  76 /*******************************************************************************
  77  *
  78  * FUNCTION:    acpi_ns_get_pathname_length
  79  *
  80  * PARAMETERS:  node        - Namespace node
  81  *
  82  * RETURN:      Length of path, including prefix
  83  *
  84  * DESCRIPTION: Get the length of the pathname string for this node
  85  *
  86  ******************************************************************************/
  87
  88 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
  89 {
  90         acpi_size size;
  91
  92         ACPI_FUNCTION_ENTRY();
  93
  94         size = acpi_ns_build_normalized_path(node, NULL, 0, FALSE);
  95         return (size);
  96 }
  97
  98 /*******************************************************************************
  99  *
 100  * FUNCTION:    acpi_ns_handle_to_pathname
 101  *
 102  * PARAMETERS:  target_handle           - Handle of named object whose name is
 103  *                                        to be found
 104  *              buffer                  - Where the pathname is returned
 105  *              no_trailing             - Remove trailing '_' for each name
 106  *                                        segment
 107  *
 108  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 109  *
 110  * DESCRIPTION: Build and return a full namespace pathname
 111  *
 112  ******************************************************************************/
 113
 114 acpi_status
 115 acpi_ns_handle_to_pathname(acpi_handle target_handle,
 116                            struct acpi_buffer *buffer, u8 no_trailing)
 117 {
 118         acpi_status status;
 119         struct acpi_namespace_node *node;
 120         acpi_size required_size;
 121
 122         ACPI_FUNCTION_TRACE_PTR(ns_handle_to_pathname, target_handle);
 123
 124         node = acpi_ns_validate_handle(target_handle);
 125         if (!node) {
 126                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 127         }
 128
 129         /* Determine size required for the caller buffer */
 130
 131         required_size =
 132             acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
 133         if (!required_size) {
 134                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 135         }
 136
 137         /* Validate/Allocate/Clear caller buffer */
 138
 139         status = acpi_ut_initialize_buffer(buffer, required_size);
 140         if (ACPI_FAILURE(status)) {
 141                 return_ACPI_STATUS(status);
 142         }
 143
 144         /* Build the path in the caller buffer */
 145
 146         (void)acpi_ns_build_normalized_path(node, buffer->pointer,
 147                                             required_size, no_trailing);
 148         if (ACPI_FAILURE(status)) {
 149                 return_ACPI_STATUS(status);
 150         }
 151
 152         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
 153                           (char *)buffer->pointer, (u32) required_size));
 154         return_ACPI_STATUS(AE_OK);
 155 }
 156
 157 /*******************************************************************************
 158  *
 159  * FUNCTION:    acpi_ns_build_normalized_path
 160  *
 161  * PARAMETERS:  node        - Namespace node
 162  *              full_path   - Where the path name is returned
 163  *              path_size   - Size of returned path name buffer
 164  *              no_trailing - Remove trailing '_' from each name segment
 165  *
 166  * RETURN:      Return 1 if the AML path is empty, otherwise returning (length
 167  *              of pathname + 1) which means the 'FullPath' contains a trailing
 168  *              null.
 169  *
 170  * DESCRIPTION: Build and return a full namespace pathname.
 171  *              Note that if the size of 'FullPath' isn't large enough to
 172  *              contain the namespace node's path name, the actual required
 173  *              buffer length is returned, and it should be greater than
 174  *              'PathSize'. So callers are able to check the returning value
 175  *              to determine the buffer size of 'FullPath'.
 176  *
 177  ******************************************************************************/
 178
 179 u32
 180 acpi_ns_build_normalized_path(struct acpi_namespace_node *node,
 181                               char *full_path, u32 path_size, u8 no_trailing)
 182 {
 183         u32 length = 0, i;
 184         char name[ACPI_NAME_SIZE];
 185         u8 do_no_trailing;
 186         char c, *left, *right;
 187         struct acpi_namespace_node *next_node;
 188
 189         ACPI_FUNCTION_TRACE_PTR(ns_build_normalized_path, node);
 190
 191 #define ACPI_PATH_PUT8(path, size, byte, length)    \
 192         do {                                            \
 193                 if ((length) < (size))                      \
 194                 {                                           \
 195                         (path)[(length)] = (byte);              \
 196                 }                                           \
 197                 (length)++;                                 \
 198         } while (0)
 199
 200         /*
 201          * Make sure the path_size is correct, so that we don't need to
 202          * validate both full_path and path_size.
 203          */
 204         if (!full_path) {
 205                 path_size = 0;
 206         }
 207
 208         if (!node) {
 209                 goto build_trailing_null;
 210         }
 211
 212         next_node = node;
 213         while (next_node && next_node != acpi_gbl_root_node) {
 214                 if (next_node != node) {
 215                         ACPI_PATH_PUT8(full_path, path_size,
 216                                        AML_DUAL_NAME_PREFIX, length);
 217                 }
 218
 219                 ACPI_MOVE_32_TO_32(name, &next_node->name);
 220                 do_no_trailing = no_trailing;
 221                 for (i = 0; i < 4; i++) {
 222                         c = name[4 - i - 1];
 223                         if (do_no_trailing && c != '_') {
 224                                 do_no_trailing = FALSE;
 225                         }
 226                         if (!do_no_trailing) {
 227                                 ACPI_PATH_PUT8(full_path, path_size, c, length);
 228                         }
 229                 }
 230
 231                 next_node = next_node->parent;
 232         }
 233
 234         ACPI_PATH_PUT8(full_path, path_size, AML_ROOT_PREFIX, length);
 235
 236         /* Reverse the path string */
 237
 238         if (length <= path_size) {
 239                 left = full_path;
 240                 right = full_path + length - 1;
 241
 242                 while (left < right) {
 243                         c = *left;
 244                         *left++ = *right;
 245                         *right-- = c;
 246                 }
 247         }
 248
 249         /* Append the trailing null */
 250
 251 build_trailing_null:
 252         ACPI_PATH_PUT8(full_path, path_size, '\0', length);
 253
 254 #undef ACPI_PATH_PUT8
 255
 256         return_UINT32(length);
 257 }
 258
 259 /*******************************************************************************
 260  *
 261  * FUNCTION:    acpi_ns_get_normalized_pathname
 262  *
 263  * PARAMETERS:  node            - Namespace node whose pathname is needed
 264  *              no_trailing     - Remove trailing '_' from each name segment
 265  *
 266  * RETURN:      Pointer to storage containing the fully qualified name of
 267  *              the node, In external format (name segments separated by path
 268  *              separators.)
 269  *
 270  * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
 271  *              for error and debug statements. All trailing '_' will be
 272  *              removed from the full pathname if 'NoTrailing' is specified..
 273  *
 274  ******************************************************************************/
 275
 276 char *acpi_ns_get_normalized_pathname(struct acpi_namespace_node *node,
 277                                       u8 no_trailing)
 278 {
 279         char *name_buffer;
 280         acpi_size size;
 281
 282         ACPI_FUNCTION_TRACE_PTR(ns_get_normalized_pathname, node);
 283
 284         /* Calculate required buffer size based on depth below root */
 285
 286         size = acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
 287         if (!size) {
 288                 return_PTR(NULL);
 289         }
 290
 291         /* Allocate a buffer to be returned to caller */
 292
 293         name_buffer = ACPI_ALLOCATE_ZEROED(size);
 294         if (!name_buffer) {
 295                 ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
 296                 return_PTR(NULL);
 297         }
 298
 299         /* Build the path in the allocated buffer */
 300
 301         (void)acpi_ns_build_normalized_path(node, name_buffer, size,
 302                                             no_trailing);
 303
 304         return_PTR(name_buffer);
 305 }