drivers/acpi/namespace/nssearch.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nssearch - Namespace search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2004, 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, "Searching %s (%p) For [%4.4s] (%s)\n",
 100                                 scope_name, node, (char *) &target_name, acpi_ut_get_type_name (type)));
 101
 102                         ACPI_MEM_FREE (scope_name);
 103                 }
 104         }
 105 #endif
 106
 107         /*
 108          * Search for name at this namespace level, which is to say that we
 109          * must search for the name among the children of this object
 110          */
 111         next_node = node->child;
 112         while (next_node) {
 113                 /* Check for match against the name */
 114
 115                 if (next_node->name.integer == target_name) {
 116                         /* Resolve a control method alias if any */
 117
 118                         if (acpi_ns_get_type (next_node) == ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 119                                 next_node = ACPI_CAST_PTR (struct acpi_namespace_node, next_node->object);
 120                         }
 121
 122                         /*
 123                          * Found matching entry.
 124                          */
 125                         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 126                                 "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
 127                                 (char *) &target_name, acpi_ut_get_type_name (next_node->type),
 128                                 next_node, acpi_ut_get_node_name (node), node));
 129
 130                         *return_node = next_node;
 131                         return_ACPI_STATUS (AE_OK);
 132                 }
 133
 134                 /*
 135                  * The last entry in the list points back to the parent,
 136                  * so a flag is used to indicate the end-of-list
 137                  */
 138                 if (next_node->flags & ANOBJ_END_OF_PEER_LIST) {
 139                         /* Searched entire list, we are done */
 140
 141                         break;
 142                 }
 143
 144                 /* Didn't match name, move on to the next peer object */
 145
 146                 next_node = next_node->peer;
 147         }
 148
 149         /* Searched entire namespace level, not found */
 150
 151         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 152                 "Name [%4.4s] (%s) not found in search in scope [%4.4s] %p first child %p\n",
 153                 (char *) &target_name, acpi_ut_get_type_name (type),
 154                 acpi_ut_get_node_name (node), node, node->child));
 155
 156         return_ACPI_STATUS (AE_NOT_FOUND);
 157 }
 158
 159
 160 /*******************************************************************************
 161  *
 162  * FUNCTION:    acpi_ns_search_parent_tree
 163  *
 164  * PARAMETERS:  *target_name        - Ascii ACPI name to search for
 165  *              *Node               - Starting node where search will begin
 166  *              Type                - Object type to match
 167  *              **return_node       - Where the matched Named Obj is returned
 168  *
 169  * RETURN:      Status
 170  *
 171  * DESCRIPTION: Called when a name has not been found in the current namespace
 172  *              level.  Before adding it or giving up, ACPI scope rules require
 173  *              searching enclosing scopes in cases identified by acpi_ns_local().
 174  *
 175  *              "A name is located by finding the matching name in the current
 176  *              name space, and then in the parent name space. If the parent
 177  *              name space does not contain the name, the search continues
 178  *              recursively until either the name is found or the name space
 179  *              does not have a parent (the root of the name space).  This
 180  *              indicates that the name is not found" (From ACPI Specification,
 181  *              section 5.3)
 182  *
 183  ******************************************************************************/
 184
 185 static acpi_status
 186 acpi_ns_search_parent_tree (
 187         u32                             target_name,
 188         struct acpi_namespace_node      *node,
 189         acpi_object_type                type,
 190         struct acpi_namespace_node      **return_node)
 191 {
 192         acpi_status                     status;
 193         struct acpi_namespace_node      *parent_node;
 194
 195
 196         ACPI_FUNCTION_TRACE ("ns_search_parent_tree");
 197
 198
 199         parent_node = acpi_ns_get_parent_node (node);
 200
 201         /*
 202          * If there is no parent (i.e., we are at the root) or
 203          * type is "local", we won't be searching the parent tree.
 204          */
 205         if (!parent_node) {
 206                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 207                         (char *) &target_name));
 208                  return_ACPI_STATUS (AE_NOT_FOUND);
 209         }
 210
 211         if (acpi_ns_local (type)) {
 212                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 213                         "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 214                         (char *) &target_name, acpi_ut_get_type_name (type)));
 215                 return_ACPI_STATUS (AE_NOT_FOUND);
 216         }
 217
 218         /* Search the parent tree */
 219
 220         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES, "Searching parent for %4.4s\n", (char *) &target_name));
 221
 222         /*
 223          * Search parents until found the target or we have backed up to
 224          * the root
 225          */
 226         while (parent_node) {
 227                 /*
 228                  * Search parent scope.  Use TYPE_ANY because we don't care about the
 229                  * object type at this point, we only care about the existence of
 230                  * the actual name we are searching for.  Typechecking comes later.
 231                  */
 232                 status = acpi_ns_search_node (target_name, parent_node,
 233                                    ACPI_TYPE_ANY, return_node);
 234                 if (ACPI_SUCCESS (status)) {
 235                         return_ACPI_STATUS (status);
 236                 }
 237
 238                 /*
 239                  * Not found here, go up another level
 240                  * (until we reach the root)
 241                  */
 242                 parent_node = acpi_ns_get_parent_node (parent_node);
 243         }
 244
 245         /* Not found in parent tree */
 246
 247         return_ACPI_STATUS (AE_NOT_FOUND);
 248 }
 249
 250
 251 /*******************************************************************************
 252  *
 253  * FUNCTION:    acpi_ns_search_and_enter
 254  *
 255  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 256  *              walk_state          - Current state of the walk
 257  *              *Node               - Starting node where search will begin
 258  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 259  *                                    Otherwise,search only.
 260  *              Type                - Object type to match
 261  *              Flags               - Flags describing the search restrictions
 262  *              **return_node       - Where the Node is returned
 263  *
 264  * RETURN:      Status
 265  *
 266  * DESCRIPTION: Search for a name segment in a single namespace level,
 267  *              optionally adding it if it is not found.  If the passed
 268  *              Type is not Any and the type previously stored in the
 269  *              entry was Any (i.e. unknown), update the stored type.
 270  *
 271  *              In ACPI_IMODE_EXECUTE, search only.
 272  *              In other modes, search and add if not found.
 273  *
 274  ******************************************************************************/
 275
 276 acpi_status
 277 acpi_ns_search_and_enter (
 278         u32                             target_name,
 279         struct acpi_walk_state          *walk_state,
 280         struct acpi_namespace_node      *node,
 281         acpi_interpreter_mode           interpreter_mode,
 282         acpi_object_type                type,
 283         u32                             flags,
 284         struct acpi_namespace_node      **return_node)
 285 {
 286         acpi_status                     status;
 287         struct acpi_namespace_node      *new_node;
 288
 289
 290         ACPI_FUNCTION_TRACE ("ns_search_and_enter");
 291
 292
 293         /* Parameter validation */
 294
 295         if (!node || !target_name || !return_node) {
 296                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Null param: Node %p Name %X return_node %p\n",
 297                         node, target_name, return_node));
 298
 299                 ACPI_REPORT_ERROR (("ns_search_and_enter: Null parameter\n"));
 300                 return_ACPI_STATUS (AE_BAD_PARAMETER);
 301         }
 302
 303         /* Name must consist of printable characters */
 304
 305         if (!acpi_ut_valid_acpi_name (target_name)) {
 306                 ACPI_REPORT_ERROR (("ns_search_and_enter: Bad character in ACPI Name: %X\n",
 307                         target_name));
 308                 return_ACPI_STATUS (AE_BAD_CHARACTER);
 309         }
 310
 311         /* Try to find the name in the namespace level specified by the caller */
 312
 313         *return_node = ACPI_ENTRY_NOT_FOUND;
 314         status = acpi_ns_search_node (target_name, node, type, return_node);
 315         if (status != AE_NOT_FOUND) {
 316                 /*
 317                  * If we found it AND the request specifies that a find is an error,
 318                  * return the error
 319                  */
 320                 if ((status == AE_OK) &&
 321                         (flags & ACPI_NS_ERROR_IF_FOUND)) {
 322                         status = AE_ALREADY_EXISTS;
 323                 }
 324
 325                 /*
 326                  * Either found it or there was an error
 327                  * -- finished either way
 328                  */
 329                 return_ACPI_STATUS (status);
 330         }
 331
 332         /*
 333          * The name was not found.  If we are NOT performing the
 334          * first pass (name entry) of loading the namespace, search
 335          * the parent tree (all the way to the root if necessary.)
 336          * We don't want to perform the parent search when the
 337          * namespace is actually being loaded.  We want to perform
 338          * the search when namespace references are being resolved
 339          * (load pass 2) and during the execution phase.
 340          */
 341         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 342                 (flags & ACPI_NS_SEARCH_PARENT)) {
 343                 /*
 344                  * Not found at this level - search parent tree according
 345                  * to ACPI specification
 346                  */
 347                 status = acpi_ns_search_parent_tree (target_name, node,
 348                                  type, return_node);
 349                 if (ACPI_SUCCESS (status)) {
 350                         return_ACPI_STATUS (status);
 351                 }
 352         }
 353
 354         /*
 355          * In execute mode, just search, never add names.  Exit now.
 356          */
 357         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 358                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES, "%4.4s Not found in %p [Not adding]\n",
 359                         (char *) &target_name, node));
 360
 361                 return_ACPI_STATUS (AE_NOT_FOUND);
 362         }
 363
 364         /* Create the new named object */
 365
 366         new_node = acpi_ns_create_node (target_name);
 367         if (!new_node) {
 368                 return_ACPI_STATUS (AE_NO_MEMORY);
 369         }
 370
 371         /* Install the new object into the parent's list of children */
 372
 373         acpi_ns_install_node (walk_state, node, new_node, type);
 374         *return_node = new_node;
 375
 376         return_ACPI_STATUS (AE_OK);
 377 }
 378