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