drivers/acpi/namespace/nssearch.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nssearch - Namespace 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
  45 #include <acpi/acpi.h>
  46 #include <acpi/acnamesp.h>
  47
  48
  49 #define _COMPONENT          ACPI_NAMESPACE
  50          ACPI_MODULE_NAME    ("nssearch")
  51
  52 /* Local prototypes */
  53
  54 static acpi_status
  55 acpi_ns_search_parent_tree (
  56         u32                             target_name,
  57         struct acpi_namespace_node      *node,
  58         acpi_object_type                type,
  59         struct acpi_namespace_node      **return_node);
  60
  61
  62 /*******************************************************************************
  63  *
  64  * FUNCTION:    acpi_ns_search_node
  65  *
  66  * PARAMETERS:  target_name     - Ascii ACPI name to search for
  67  *              Node            - Starting node where search will begin
  68  *              Type            - Object type to match
  69  *              return_node     - Where the matched Named obj is returned
  70  *
  71  * RETURN:      Status
  72  *
  73  * DESCRIPTION: Search a single level of the namespace.  Performs a
  74  *              simple search of the specified level, and does not add
  75  *              entries or search parents.
  76  *
  77  *
  78  *      Named object lists are built (and subsequently dumped) in the
  79  *      order in which the names are encountered during the namespace load;
  80  *
  81  *      All namespace searching is linear in this implementation, but
  82  *      could be easily modified to support any improved search
  83  *      algorithm.  However, the linear search was chosen for simplicity
  84  *      and because the trees are small and the other interpreter
  85  *      execution overhead is relatively high.
  86  *
  87  ******************************************************************************/
  88
  89 acpi_status
  90 acpi_ns_search_node (
  91         u32                             target_name,
  92         struct acpi_namespace_node      *node,
  93         acpi_object_type                type,
  94         struct acpi_namespace_node      **return_node)
  95 {
  96         struct acpi_namespace_node      *next_node;
  97
  98
  99         ACPI_FUNCTION_TRACE ("ns_search_node");
 100
 101
 102 #ifdef ACPI_DEBUG_OUTPUT
 103         if (ACPI_LV_NAMES & acpi_dbg_level) {
 104                 char                        *scope_name;
 105
 106                 scope_name = acpi_ns_get_external_pathname (node);
 107                 if (scope_name) {
 108                         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 109                                 "Searching %s (%p) For [%4.4s] (%s)\n",
 110                                 scope_name, node, (char *) &target_name,
 111                                 acpi_ut_get_type_name (type)));
 112
 113                         ACPI_MEM_FREE (scope_name);
 114                 }
 115         }
 116 #endif
 117
 118         /*
 119          * Search for name at this namespace level, which is to say that we
 120          * must search for the name among the children of this object
 121          */
 122         next_node = node->child;
 123         while (next_node) {
 124                 /* Check for match against the name */
 125
 126                 if (next_node->name.integer == target_name) {
 127                         /* Resolve a control method alias if any */
 128
 129                         if (acpi_ns_get_type (next_node) == ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 130                                 next_node = ACPI_CAST_PTR (struct acpi_namespace_node, next_node->object);
 131                         }
 132
 133                         /*
 134                          * Found matching entry.
 135                          */
 136                         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 137                                 "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
 138                                 (char *) &target_name, acpi_ut_get_type_name (next_node->type),
 139                                 next_node, acpi_ut_get_node_name (node), node));
 140
 141                         *return_node = next_node;
 142                         return_ACPI_STATUS (AE_OK);
 143                 }
 144
 145                 /*
 146                  * The last entry in the list points back to the parent,
 147                  * so a flag is used to indicate the end-of-list
 148                  */
 149                 if (next_node->flags & ANOBJ_END_OF_PEER_LIST) {
 150                         /* Searched entire list, we are done */
 151
 152                         break;
 153                 }
 154
 155                 /* Didn't match name, move on to the next peer object */
 156
 157                 next_node = next_node->peer;
 158         }
 159
 160         /* Searched entire namespace level, not found */
 161
 162         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 163                 "Name [%4.4s] (%s) not found in search in scope [%4.4s] %p first child %p\n",
 164                 (char *) &target_name, acpi_ut_get_type_name (type),
 165                 acpi_ut_get_node_name (node), node, node->child));
 166
 167         return_ACPI_STATUS (AE_NOT_FOUND);
 168 }
 169
 170
 171 /*******************************************************************************
 172  *
 173  * FUNCTION:    acpi_ns_search_parent_tree
 174  *
 175  * PARAMETERS:  target_name     - Ascii ACPI name to search for
 176  *              Node            - Starting node where search will begin
 177  *              Type            - Object type to match
 178  *              return_node     - Where the matched Node is returned
 179  *
 180  * RETURN:      Status
 181  *
 182  * DESCRIPTION: Called when a name has not been found in the current namespace
 183  *              level.  Before adding it or giving up, ACPI scope rules require
 184  *              searching enclosing scopes in cases identified by acpi_ns_local().
 185  *
 186  *              "A name is located by finding the matching name in the current
 187  *              name space, and then in the parent name space. If the parent
 188  *              name space does not contain the name, the search continues
 189  *              recursively until either the name is found or the name space
 190  *              does not have a parent (the root of the name space).  This
 191  *              indicates that the name is not found" (From ACPI Specification,
 192  *              section 5.3)
 193  *
 194  ******************************************************************************/
 195
 196 static acpi_status
 197 acpi_ns_search_parent_tree (
 198         u32                             target_name,
 199         struct acpi_namespace_node      *node,
 200         acpi_object_type                type,
 201         struct acpi_namespace_node      **return_node)
 202 {
 203         acpi_status                     status;
 204         struct acpi_namespace_node      *parent_node;
 205
 206
 207         ACPI_FUNCTION_TRACE ("ns_search_parent_tree");
 208
 209
 210         parent_node = acpi_ns_get_parent_node (node);
 211
 212         /*
 213          * If there is no parent (i.e., we are at the root) or type is "local",
 214          * we won't be searching the parent tree.
 215          */
 216         if (!parent_node) {
 217                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 218                         (char *) &target_name));
 219                 return_ACPI_STATUS (AE_NOT_FOUND);
 220         }
 221
 222         if (acpi_ns_local (type)) {
 223                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 224                         "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 225                         (char *) &target_name, acpi_ut_get_type_name (type)));
 226                 return_ACPI_STATUS (AE_NOT_FOUND);
 227         }
 228
 229         /* Search the parent tree */
 230
 231         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 232                 "Searching parent [%4.4s] for [%4.4s]\n",
 233                 acpi_ut_get_node_name (parent_node), (char *) &target_name));
 234
 235         /*
 236          * Search parents until target is found or we have backed up to the root
 237          */
 238         while (parent_node) {
 239                 /*
 240                  * Search parent scope.  Use TYPE_ANY because we don't care about the
 241                  * object type at this point, we only care about the existence of
 242                  * the actual name we are searching for.  Typechecking comes later.
 243                  */
 244                 status = acpi_ns_search_node (target_name, parent_node,
 245                                   ACPI_TYPE_ANY, return_node);
 246                 if (ACPI_SUCCESS (status)) {
 247                         return_ACPI_STATUS (status);
 248                 }
 249
 250                 /*
 251                  * Not found here, go up another level
 252                  * (until we reach the root)
 253                  */
 254                 parent_node = acpi_ns_get_parent_node (parent_node);
 255         }
 256
 257         /* Not found in parent tree */
 258
 259         return_ACPI_STATUS (AE_NOT_FOUND);
 260 }
 261
 262
 263 /*******************************************************************************
 264  *
 265  * FUNCTION:    acpi_ns_search_and_enter
 266  *
 267  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 268  *              walk_state          - Current state of the walk
 269  *              Node                - Starting node where search will begin
 270  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 271  *                                    Otherwise,search only.
 272  *              Type                - Object type to match
 273  *              Flags               - Flags describing the search restrictions
 274  *              return_node         - Where the Node is returned
 275  *
 276  * RETURN:      Status
 277  *
 278  * DESCRIPTION: Search for a name segment in a single namespace level,
 279  *              optionally adding it if it is not found.  If the passed
 280  *              Type is not Any and the type previously stored in the
 281  *              entry was Any (i.e. unknown), update the stored type.
 282  *
 283  *              In ACPI_IMODE_EXECUTE, search only.
 284  *              In other modes, search and add if not found.
 285  *
 286  ******************************************************************************/
 287
 288 acpi_status
 289 acpi_ns_search_and_enter (
 290         u32                             target_name,
 291         struct acpi_walk_state          *walk_state,
 292         struct acpi_namespace_node      *node,
 293         acpi_interpreter_mode           interpreter_mode,
 294         acpi_object_type                type,
 295         u32                             flags,
 296         struct acpi_namespace_node      **return_node)
 297 {
 298         acpi_status                     status;
 299         struct acpi_namespace_node      *new_node;
 300
 301
 302         ACPI_FUNCTION_TRACE ("ns_search_and_enter");
 303
 304
 305         /* Parameter validation */
 306
 307         if (!node || !target_name || !return_node) {
 308                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
 309                         "Null param: Node %p Name %X return_node %p\n",
 310                         node, target_name, return_node));
 311
 312                 ACPI_REPORT_ERROR (("ns_search_and_enter: Null parameter\n"));
 313                 return_ACPI_STATUS (AE_BAD_PARAMETER);
 314         }
 315
 316         /* Name must consist of printable characters */
 317
 318         if (!acpi_ut_valid_acpi_name (target_name)) {
 319                 ACPI_REPORT_ERROR (("ns_search_and_enter: Bad character in ACPI Name: %X\n",
 320                         target_name));
 321                 return_ACPI_STATUS (AE_BAD_CHARACTER);
 322         }
 323
 324         /* Try to find the name in the namespace level specified by the caller */
 325
 326         *return_node = ACPI_ENTRY_NOT_FOUND;
 327         status = acpi_ns_search_node (target_name, node, type, return_node);
 328         if (status != AE_NOT_FOUND) {
 329                 /*
 330                  * If we found it AND the request specifies that a find is an error,
 331                  * return the error
 332                  */
 333                 if ((status == AE_OK) &&
 334                         (flags & ACPI_NS_ERROR_IF_FOUND)) {
 335                         status = AE_ALREADY_EXISTS;
 336                 }
 337
 338                 /*
 339                  * Either found it or there was an error
 340                  * -- finished either way
 341                  */
 342                 return_ACPI_STATUS (status);
 343         }
 344
 345         /*
 346          * The name was not found.  If we are NOT performing the first pass
 347          * (name entry) of loading the namespace, search the parent tree (all the
 348          * way to the root if necessary.) We don't want to perform the parent
 349          * search when the namespace is actually being loaded.  We want to perform
 350          * the search when namespace references are being resolved (load pass 2)
 351          * and during the execution phase.
 352          */
 353         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 354                 (flags & ACPI_NS_SEARCH_PARENT)) {
 355                 /*
 356                  * Not found at this level - search parent tree according to the
 357                  * ACPI specification
 358                  */
 359                 status = acpi_ns_search_parent_tree (target_name, node, type, return_node);
 360                 if (ACPI_SUCCESS (status)) {
 361                         return_ACPI_STATUS (status);
 362                 }
 363         }
 364
 365         /*
 366          * In execute mode, just search, never add names.  Exit now.
 367          */
 368         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 369                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 370                         "%4.4s Not found in %p [Not adding]\n",
 371                         (char *) &target_name, node));
 372
 373                 return_ACPI_STATUS (AE_NOT_FOUND);
 374         }
 375
 376         /* Create the new named object */
 377
 378         new_node = acpi_ns_create_node (target_name);
 379         if (!new_node) {
 380                 return_ACPI_STATUS (AE_NO_MEMORY);
 381         }
 382
 383         /* Install the new object into the parent's list of children */
 384
 385         acpi_ns_install_node (walk_state, node, new_node, type);
 386         *return_node = new_node;
 387
 388         return_ACPI_STATUS (AE_OK);
 389 }
 390