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   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_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
 118                 /* Check for match against the name */
 119
 120                 if (next_node->name.integer == target_name) {
 121
 122                         /* Resolve a control method alias if any */
 123
 124                         if (acpi_ns_get_type(next_node) ==
 125                             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 126                                 next_node =
 127                                     ACPI_CAST_PTR(struct acpi_namespace_node,
 128                                                   next_node->object);
 129                         }
 130
 131                         /*
 132                          * Found matching entry.
 133                          */
 134                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 135                                           "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
 136                                           ACPI_CAST_PTR(char, &target_name),
 137                                           acpi_ut_get_type_name(next_node->
 138                                                                 type),
 139                                           next_node,
 140                                           acpi_ut_get_node_name(node), node));
 141
 142                         *return_node = next_node;
 143                         return_ACPI_STATUS(AE_OK);
 144                 }
 145
 146                 /*
 147                  * The last entry in the list points back to the parent,
 148                  * so a flag is used to indicate the end-of-list
 149                  */
 150                 if (next_node->flags & ANOBJ_END_OF_PEER_LIST) {
 151
 152                         /* Searched entire list, we are done */
 153
 154                         break;
 155                 }
 156
 157                 /* Didn't match name, move on to the next peer object */
 158
 159                 next_node = next_node->peer;
 160         }
 161
 162         /* Searched entire namespace level, not found */
 163
 164         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 165                           "Name [%4.4s] (%s) not found in search in scope [%4.4s] %p first child %p\n",
 166                           ACPI_CAST_PTR(char, &target_name),
 167                           acpi_ut_get_type_name(type),
 168                           acpi_ut_get_node_name(node), node, node->child));
 169
 170         return_ACPI_STATUS(AE_NOT_FOUND);
 171 }
 172
 173 /*******************************************************************************
 174  *
 175  * FUNCTION:    acpi_ns_search_parent_tree
 176  *
 177  * PARAMETERS:  target_name     - Ascii ACPI name to search for
 178  *              Node            - Starting node where search will begin
 179  *              Type            - Object type to match
 180  *              return_node     - Where the matched Node is returned
 181  *
 182  * RETURN:      Status
 183  *
 184  * DESCRIPTION: Called when a name has not been found in the current namespace
 185  *              level.  Before adding it or giving up, ACPI scope rules require
 186  *              searching enclosing scopes in cases identified by acpi_ns_local().
 187  *
 188  *              "A name is located by finding the matching name in the current
 189  *              name space, and then in the parent name space. If the parent
 190  *              name space does not contain the name, the search continues
 191  *              recursively until either the name is found or the name space
 192  *              does not have a parent (the root of the name space).  This
 193  *              indicates that the name is not found" (From ACPI Specification,
 194  *              section 5.3)
 195  *
 196  ******************************************************************************/
 197
 198 static acpi_status
 199 acpi_ns_search_parent_tree(u32 target_name,
 200                            struct acpi_namespace_node *node,
 201                            acpi_object_type type,
 202                            struct acpi_namespace_node **return_node)
 203 {
 204         acpi_status status;
 205         struct acpi_namespace_node *parent_node;
 206
 207         ACPI_FUNCTION_TRACE("ns_search_parent_tree");
 208
 209         parent_node = acpi_ns_get_parent_node(node);
 210
 211         /*
 212          * If there is no parent (i.e., we are at the root) or type is "local",
 213          * we won't be searching the parent tree.
 214          */
 215         if (!parent_node) {
 216                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 217                                   ACPI_CAST_PTR(char, &target_name)));
 218                 return_ACPI_STATUS(AE_NOT_FOUND);
 219         }
 220
 221         if (acpi_ns_local(type)) {
 222                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 223                                   "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 224                                   ACPI_CAST_PTR(char, &target_name),
 225                                   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),
 234                           ACPI_CAST_PTR(char, &target_name)));
 235
 236         /*
 237          * Search parents until target is found or we have backed up to the root
 238          */
 239         while (parent_node) {
 240                 /*
 241                  * Search parent scope.  Use TYPE_ANY because we don't care about the
 242                  * object type at this point, we only care about the existence of
 243                  * the actual name we are searching for.  Typechecking comes later.
 244                  */
 245                 status = acpi_ns_search_node(target_name, parent_node,
 246                                              ACPI_TYPE_ANY, return_node);
 247                 if (ACPI_SUCCESS(status)) {
 248                         return_ACPI_STATUS(status);
 249                 }
 250
 251                 /*
 252                  * Not found here, go up another level
 253                  * (until we reach the root)
 254                  */
 255                 parent_node = acpi_ns_get_parent_node(parent_node);
 256         }
 257
 258         /* Not found in parent tree */
 259
 260         return_ACPI_STATUS(AE_NOT_FOUND);
 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(u32 target_name,
 290                          struct acpi_walk_state *walk_state,
 291                          struct acpi_namespace_node *node,
 292                          acpi_interpreter_mode interpreter_mode,
 293                          acpi_object_type type,
 294                          u32 flags, struct acpi_namespace_node **return_node)
 295 {
 296         acpi_status status;
 297         struct acpi_namespace_node *new_node;
 298
 299         ACPI_FUNCTION_TRACE("ns_search_and_enter");
 300
 301         /* Parameter validation */
 302
 303         if (!node || !target_name || !return_node) {
 304                 ACPI_ERROR((AE_INFO,
 305                             "Null param: Node %p Name %X return_node %p",
 306                             node, target_name, return_node));
 307                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 308         }
 309
 310         /* Name must consist of printable characters */
 311
 312         if (!acpi_ut_valid_acpi_name(target_name)) {
 313                 ACPI_ERROR((AE_INFO, "Bad character in ACPI Name: %X",
 314                             target_name));
 315                 return_ACPI_STATUS(AE_BAD_CHARACTER);
 316         }
 317
 318         /* Try to find the name in the namespace level specified by the caller */
 319
 320         *return_node = ACPI_ENTRY_NOT_FOUND;
 321         status = acpi_ns_search_node(target_name, node, type, return_node);
 322         if (status != AE_NOT_FOUND) {
 323                 /*
 324                  * If we found it AND the request specifies that a find is an error,
 325                  * return the error
 326                  */
 327                 if ((status == AE_OK) && (flags & ACPI_NS_ERROR_IF_FOUND)) {
 328                         status = AE_ALREADY_EXISTS;
 329                 }
 330
 331                 /*
 332                  * Either found it or there was an error
 333                  * -- finished either way
 334                  */
 335                 return_ACPI_STATUS(status);
 336         }
 337
 338         /*
 339          * The name was not found.  If we are NOT performing the first pass
 340          * (name entry) of loading the namespace, search the parent tree (all the
 341          * way to the root if necessary.) We don't want to perform the parent
 342          * search when the namespace is actually being loaded.  We want to perform
 343          * the search when namespace references are being resolved (load pass 2)
 344          * and during the execution phase.
 345          */
 346         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 347             (flags & ACPI_NS_SEARCH_PARENT)) {
 348                 /*
 349                  * Not found at this level - search parent tree according to the
 350                  * ACPI specification
 351                  */
 352                 status =
 353                     acpi_ns_search_parent_tree(target_name, node, type,
 354                                                return_node);
 355                 if (ACPI_SUCCESS(status)) {
 356                         return_ACPI_STATUS(status);
 357                 }
 358         }
 359
 360         /*
 361          * In execute mode, just search, never add names.  Exit now.
 362          */
 363         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 364                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 365                                   "%4.4s Not found in %p [Not adding]\n",
 366                                   ACPI_CAST_PTR(char, &target_name), node));
 367
 368                 return_ACPI_STATUS(AE_NOT_FOUND);
 369         }
 370
 371         /* Create the new named object */
 372
 373         new_node = acpi_ns_create_node(target_name);
 374         if (!new_node) {
 375                 return_ACPI_STATUS(AE_NO_MEMORY);
 376         }
 377
 378         /* Install the new object into the parent's list of children */
 379
 380         acpi_ns_install_node(walk_state, node, new_node, type);
 381         *return_node = new_node;
 382
 383         return_ACPI_STATUS(AE_OK);
 384 }