drivers/acpi/namespace/nssearch.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nssearch - Namespace search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2006, 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 #include <acpi/acpi.h>
  45 #include <acpi/acnamesp.h>
  46
  47 #define _COMPONENT          ACPI_NAMESPACE
  48 ACPI_MODULE_NAME("nssearch")
  49
  50 /* Local prototypes */
  51 static acpi_status
  52 acpi_ns_search_parent_tree(u32 target_name,
  53                            struct acpi_namespace_node *node,
  54                            acpi_object_type type,
  55                            struct acpi_namespace_node **return_node);
  56
  57 /*******************************************************************************
  58  *
  59  * FUNCTION:    acpi_ns_search_node
  60  *
  61  * PARAMETERS:  target_name     - Ascii ACPI name to search for
  62  *              Node            - Starting node where search will begin
  63  *              Type            - Object type to match
  64  *              return_node     - Where the matched Named obj is returned
  65  *
  66  * RETURN:      Status
  67  *
  68  * DESCRIPTION: Search a single level of the namespace.  Performs a
  69  *              simple search of the specified level, and does not add
  70  *              entries or search parents.
  71  *
  72  *
  73  *      Named object lists are built (and subsequently dumped) in the
  74  *      order in which the names are encountered during the namespace load;
  75  *
  76  *      All namespace searching is linear in this implementation, but
  77  *      could be easily modified to support any improved search
  78  *      algorithm.  However, the linear search was chosen for simplicity
  79  *      and because the trees are small and the other interpreter
  80  *      execution overhead is relatively high.
  81  *
  82  ******************************************************************************/
  83
  84 acpi_status
  85 acpi_ns_search_node(u32 target_name,
  86                     struct acpi_namespace_node *node,
  87                     acpi_object_type type,
  88                     struct acpi_namespace_node **return_node)
  89 {
  90         struct acpi_namespace_node *next_node;
  91
  92         ACPI_FUNCTION_TRACE("ns_search_node");
  93
  94 #ifdef ACPI_DEBUG_OUTPUT
  95         if (ACPI_LV_NAMES & acpi_dbg_level) {
  96                 char *scope_name;
  97
  98                 scope_name = acpi_ns_get_external_pathname(node);
  99                 if (scope_name) {
 100                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 101                                           "Searching %s (%p) For [%4.4s] (%s)\n",
 102                                           scope_name, node, ACPI_CAST_PTR(char,
 103                                                                           &target_name),
 104                                           acpi_ut_get_type_name(type)));
 105
 106                         ACPI_MEM_FREE(scope_name);
 107                 }
 108         }
 109 #endif
 110
 111         /*
 112          * Search for name at this namespace level, which is to say that we
 113          * must search for the name among the children of this object
 114          */
 115         next_node = node->child;
 116         while (next_node) {
 117                 /* Check for match against the name */
 118
 119                 if (next_node->name.integer == target_name) {
 120                         /* Resolve a control method alias if any */
 121
 122                         if (acpi_ns_get_type(next_node) ==
 123                             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 124                                 next_node =
 125                                     ACPI_CAST_PTR(struct acpi_namespace_node,
 126                                                   next_node->object);
 127                         }
 128
 129                         /*
 130                          * Found matching entry.
 131                          */
 132                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 133                                           "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
 134                                           ACPI_CAST_PTR(char, &target_name),
 135                                           acpi_ut_get_type_name(next_node->
 136                                                                 type),
 137                                           next_node,
 138                                           acpi_ut_get_node_name(node), node));
 139
 140                         *return_node = next_node;
 141                         return_ACPI_STATUS(AE_OK);
 142                 }
 143
 144                 /*
 145                  * The last entry in the list points back to the parent,
 146                  * so a flag is used to indicate the end-of-list
 147                  */
 148                 if (next_node->flags & ANOBJ_END_OF_PEER_LIST) {
 149                         /* Searched entire list, we are done */
 150
 151                         break;
 152                 }
 153
 154                 /* Didn't match name, move on to the next peer object */
 155
 156                 next_node = next_node->peer;
 157         }
 158
 159         /* Searched entire namespace level, not found */
 160
 161         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 162                           "Name [%4.4s] (%s) not found in search in scope [%4.4s] %p first child %p\n",
 163                           ACPI_CAST_PTR(char, &target_name),
 164                           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  * FUNCTION:    acpi_ns_search_parent_tree
 173  *
 174  * PARAMETERS:  target_name     - Ascii ACPI name to search for
 175  *              Node            - Starting node where search will begin
 176  *              Type            - Object type to match
 177  *              return_node     - Where the matched Node is returned
 178  *
 179  * RETURN:      Status
 180  *
 181  * DESCRIPTION: Called when a name has not been found in the current namespace
 182  *              level.  Before adding it or giving up, ACPI scope rules require
 183  *              searching enclosing scopes in cases identified by acpi_ns_local().
 184  *
 185  *              "A name is located by finding the matching name in the current
 186  *              name space, and then in the parent name space. If the parent
 187  *              name space does not contain the name, the search continues
 188  *              recursively until either the name is found or the name space
 189  *              does not have a parent (the root of the name space).  This
 190  *              indicates that the name is not found" (From ACPI Specification,
 191  *              section 5.3)
 192  *
 193  ******************************************************************************/
 194
 195 static acpi_status
 196 acpi_ns_search_parent_tree(u32 target_name,
 197                            struct acpi_namespace_node *node,
 198                            acpi_object_type type,
 199                            struct acpi_namespace_node **return_node)
 200 {
 201         acpi_status status;
 202         struct acpi_namespace_node *parent_node;
 203
 204         ACPI_FUNCTION_TRACE("ns_search_parent_tree");
 205
 206         parent_node = acpi_ns_get_parent_node(node);
 207
 208         /*
 209          * If there is no parent (i.e., we are at the root) or type is "local",
 210          * we won't be searching the parent tree.
 211          */
 212         if (!parent_node) {
 213                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 214                                   ACPI_CAST_PTR(char, &target_name)));
 215                 return_ACPI_STATUS(AE_NOT_FOUND);
 216         }
 217
 218         if (acpi_ns_local(type)) {
 219                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 220                                   "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 221                                   ACPI_CAST_PTR(char, &target_name),
 222                                   acpi_ut_get_type_name(type)));
 223                 return_ACPI_STATUS(AE_NOT_FOUND);
 224         }
 225
 226         /* Search the parent tree */
 227
 228         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 229                           "Searching parent [%4.4s] for [%4.4s]\n",
 230                           acpi_ut_get_node_name(parent_node),
 231                           ACPI_CAST_PTR(char, &target_name)));
 232
 233         /*
 234          * Search parents until target is found or we have backed up to the root
 235          */
 236         while (parent_node) {
 237                 /*
 238                  * Search parent scope.  Use TYPE_ANY because we don't care about the
 239                  * object type at this point, we only care about the existence of
 240                  * the actual name we are searching for.  Typechecking comes later.
 241                  */
 242                 status = acpi_ns_search_node(target_name, parent_node,
 243                                              ACPI_TYPE_ANY, return_node);
 244                 if (ACPI_SUCCESS(status)) {
 245                         return_ACPI_STATUS(status);
 246                 }
 247
 248                 /*
 249                  * Not found here, go up another level
 250                  * (until we reach the root)
 251                  */
 252                 parent_node = acpi_ns_get_parent_node(parent_node);
 253         }
 254
 255         /* Not found in parent tree */
 256
 257         return_ACPI_STATUS(AE_NOT_FOUND);
 258 }
 259
 260 /*******************************************************************************
 261  *
 262  * FUNCTION:    acpi_ns_search_and_enter
 263  *
 264  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 265  *              walk_state          - Current state of the walk
 266  *              Node                - Starting node where search will begin
 267  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 268  *                                    Otherwise,search only.
 269  *              Type                - Object type to match
 270  *              Flags               - Flags describing the search restrictions
 271  *              return_node         - Where the Node is returned
 272  *
 273  * RETURN:      Status
 274  *
 275  * DESCRIPTION: Search for a name segment in a single namespace level,
 276  *              optionally adding it if it is not found.  If the passed
 277  *              Type is not Any and the type previously stored in the
 278  *              entry was Any (i.e. unknown), update the stored type.
 279  *
 280  *              In ACPI_IMODE_EXECUTE, search only.
 281  *              In other modes, search and add if not found.
 282  *
 283  ******************************************************************************/
 284
 285 acpi_status
 286 acpi_ns_search_and_enter(u32 target_name,
 287                          struct acpi_walk_state *walk_state,
 288                          struct acpi_namespace_node *node,
 289                          acpi_interpreter_mode interpreter_mode,
 290                          acpi_object_type type,
 291                          u32 flags, struct acpi_namespace_node **return_node)
 292 {
 293         acpi_status status;
 294         struct acpi_namespace_node *new_node;
 295
 296         ACPI_FUNCTION_TRACE("ns_search_and_enter");
 297
 298         /* Parameter validation */
 299
 300         if (!node || !target_name || !return_node) {
 301                 ACPI_ERROR((AE_INFO,
 302                             "Null param: Node %p Name %X return_node %p",
 303                             node, target_name, return_node));
 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_ERROR((AE_INFO, "Bad character in ACPI Name: %X",
 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) && (flags & ACPI_NS_ERROR_IF_FOUND)) {
 325                         status = AE_ALREADY_EXISTS;
 326                 }
 327
 328                 /*
 329                  * Either found it or there was an error
 330                  * -- finished either way
 331                  */
 332                 return_ACPI_STATUS(status);
 333         }
 334
 335         /*
 336          * The name was not found.  If we are NOT performing the first pass
 337          * (name entry) of loading the namespace, search the parent tree (all the
 338          * way to the root if necessary.) We don't want to perform the parent
 339          * search when the namespace is actually being loaded.  We want to perform
 340          * the search when namespace references are being resolved (load pass 2)
 341          * and during the execution phase.
 342          */
 343         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 344             (flags & ACPI_NS_SEARCH_PARENT)) {
 345                 /*
 346                  * Not found at this level - search parent tree according to the
 347                  * ACPI specification
 348                  */
 349                 status =
 350                     acpi_ns_search_parent_tree(target_name, node, type,
 351                                                return_node);
 352                 if (ACPI_SUCCESS(status)) {
 353                         return_ACPI_STATUS(status);
 354                 }
 355         }
 356
 357         /*
 358          * In execute mode, just search, never add names.  Exit now.
 359          */
 360         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 361                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 362                                   "%4.4s Not found in %p [Not adding]\n",
 363                                   ACPI_CAST_PTR(char, &target_name), node));
 364
 365                 return_ACPI_STATUS(AE_NOT_FOUND);
 366         }
 367
 368         /* Create the new named object */
 369
 370         new_node = acpi_ns_create_node(target_name);
 371         if (!new_node) {
 372                 return_ACPI_STATUS(AE_NO_MEMORY);
 373         }
 374
 375         /* Install the new object into the parent's list of children */
 376
 377         acpi_ns_install_node(walk_state, node, new_node, type);
 378         *return_node = new_node;
 379
 380         return_ACPI_STATUS(AE_OK);
 381 }