// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/*******************************************************************************
 *
 * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
 *
 ******************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"
#include "amlcode.h"
#include "acnamesp.h"
#include "acdispat.h"

#ifdef ACPI_ASL_COMPILER
#include "acdisasm.h"
#endif

#define _COMPONENT          ACPI_NAMESPACE
ACPI_MODULE_NAME("nsaccess")

/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_root_initialize
 *
 * PARAMETERS:  None
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Allocate and initialize the default root named objects
 *
 * MUTEX:       Locks namespace for entire execution
 *
 ******************************************************************************/
acpi_status acpi_ns_root_initialize(void)
{
        acpi_status status;
        const struct acpi_predefined_names *init_val = NULL;
        struct acpi_namespace_node *new_node;
        struct acpi_namespace_node *prev_node = NULL;
        union acpi_operand_object *obj_desc;
        acpi_string val = NULL;

        ACPI_FUNCTION_TRACE(ns_root_initialize);

        status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /*
         * The global root ptr is initially NULL, so a non-NULL value indicates
         * that acpi_ns_root_initialize() has already been called; just return.
         */
        if (acpi_gbl_root_node) {
                status = AE_OK;
                goto unlock_and_exit;
        }

        /*
         * Tell the rest of the subsystem that the root is initialized
         * (This is OK because the namespace is locked)
         */
        acpi_gbl_root_node = &acpi_gbl_root_node_struct;

        /* Enter the predefined names in the name table */

        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "Entering predefined entries into namespace\n"));

        /*
         * Create the initial (default) namespace.
         * This namespace looks like something similar to this:
         *
         *   ACPI Namespace (from Namespace Root):
         *    0  _GPE Scope        00203160 00
         *    0  _PR_ Scope        002031D0 00
         *    0  _SB_ Device       00203240 00 Notify Object: 0020ADD8
         *    0  _SI_ Scope        002032B0 00
         *    0  _TZ_ Device       00203320 00
         *    0  _REV Integer      00203390 00 = 0000000000000002
         *    0  _OS_ String       00203488 00 Len 14 "Microsoft Windows NT"
         *    0  _GL_ Mutex        00203580 00 Object 002035F0
         *    0  _OSI Method       00203678 00 Args 1 Len 0000 Aml 00000000
         */
        for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {
                status = AE_OK;

                /* _OSI is optional for now, will be permanent later */

                if (!strcmp(init_val->name, "_OSI")
                    && !acpi_gbl_create_osi_method) {
                        continue;
                }

                /*
                 * Create, init, and link the new predefined name
                 * Note: No need to use acpi_ns_lookup here because all the
                 * predefined names are at the root level. It is much easier to
                 * just create and link the new node(s) here.
                 */
                new_node =
                    ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_namespace_node));
                if (!new_node) {
                        status = AE_NO_MEMORY;
                        goto unlock_and_exit;
                }

                ACPI_COPY_NAMESEG(new_node->name.ascii, init_val->name);
                new_node->descriptor_type = ACPI_DESC_TYPE_NAMED;
                new_node->type = init_val->type;

                if (!prev_node) {
                        acpi_gbl_root_node_struct.child = new_node;
                } else {
                        prev_node->peer = new_node;
                }

                new_node->parent = &acpi_gbl_root_node_struct;
                prev_node = new_node;

                /*
                 * Name entered successfully. If entry in pre_defined_names[] specifies
                 * an initial value, create the initial value.
                 */
                if (init_val->val) {
                        status = acpi_os_predefined_override(init_val, &val);
                        if (ACPI_FAILURE(status)) {
                                ACPI_ERROR((AE_INFO,
                                            "Could not override predefined %s",
                                            init_val->name));
                        }

                        if (!val) {
                                val = init_val->val;
                        }

                        /*
                         * Entry requests an initial value, allocate a
                         * descriptor for it.
                         */
                        obj_desc =
                            acpi_ut_create_internal_object(init_val->type);
                        if (!obj_desc) {
                                status = AE_NO_MEMORY;
                                goto unlock_and_exit;
                        }

                        /*
                         * Convert value string from table entry to
                         * internal representation. Only types actually
                         * used for initial values are implemented here.
                         */
                        switch (init_val->type) {
                        case ACPI_TYPE_METHOD:

                                obj_desc->method.param_count =
                                    (u8) ACPI_TO_INTEGER(val);
                                obj_desc->common.flags |= AOPOBJ_DATA_VALID;

#if defined (ACPI_ASL_COMPILER)

                                /* Save the parameter count for the iASL compiler */

                                new_node->value = obj_desc->method.param_count;
#else
                                /* Mark this as a very SPECIAL method (_OSI) */

                                obj_desc->method.info_flags =
                                    ACPI_METHOD_INTERNAL_ONLY;
                                obj_desc->method.dispatch.implementation =
                                    acpi_ut_osi_implementation;
#endif
                                break;

                        case ACPI_TYPE_INTEGER:

                                obj_desc->integer.value = ACPI_TO_INTEGER(val);
                                break;

                        case ACPI_TYPE_STRING:

                                /* Build an object around the static string */

                                obj_desc->string.length = (u32)strlen(val);
                                obj_desc->string.pointer = val;
                                obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
                                break;

                        case ACPI_TYPE_MUTEX:

                                obj_desc->mutex.node = new_node;
                                obj_desc->mutex.sync_level =
                                    (u8) (ACPI_TO_INTEGER(val) - 1);

                                /* Create a mutex */

                                status =
                                    acpi_os_create_mutex(&obj_desc->mutex.
                                                         os_mutex);
                                if (ACPI_FAILURE(status)) {
                                        acpi_ut_remove_reference(obj_desc);
                                        goto unlock_and_exit;
                                }

                                /* Special case for ACPI Global Lock */

                                if (strcmp(init_val->name, "_GL_") == 0) {
                                        acpi_gbl_global_lock_mutex = obj_desc;

                                        /* Create additional counting semaphore for global lock */

                                        status =
                                            acpi_os_create_semaphore(1, 0,
                                                                     &acpi_gbl_global_lock_semaphore);
                                        if (ACPI_FAILURE(status)) {
                                                acpi_ut_remove_reference
                                                    (obj_desc);
                                                goto unlock_and_exit;
                                        }
                                }
                                break;

                        default:

                                ACPI_ERROR((AE_INFO,
                                            "Unsupported initial type value 0x%X",
                                            init_val->type));
                                acpi_ut_remove_reference(obj_desc);
                                obj_desc = NULL;
                                continue;
                        }

                        /* Store pointer to value descriptor in the Node */

                        status = acpi_ns_attach_object(new_node, obj_desc,
                                                       obj_desc->common.type);

                        /* Remove local reference to the object */

                        acpi_ut_remove_reference(obj_desc);
                }
        }

unlock_and_exit:
        (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);

        /* Save a handle to "_GPE", it is always present */

        if (ACPI_SUCCESS(status)) {
                status = acpi_ns_get_node(NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
                                          &acpi_gbl_fadt_gpe_device);
        }

        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_lookup
 *
 * PARAMETERS:  scope_info      - Current scope info block
 *              pathname        - Search pathname, in internal format
 *                                (as represented in the AML stream)
 *              type            - Type associated with name
 *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
 *              flags           - Flags describing the search restrictions
 *              walk_state      - Current state of the walk
 *              return_node     - Where the Node is placed (if found
 *                                or created successfully)
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Find or enter the passed name in the name space.
 *              Log an error if name not found in Exec mode.
 *
 * MUTEX:       Assumes namespace is locked.
 *
 ******************************************************************************/

acpi_status
acpi_ns_lookup(union acpi_generic_state *scope_info,
               char *pathname,
               acpi_object_type type,
               acpi_interpreter_mode interpreter_mode,
               u32 flags,
               struct acpi_walk_state *walk_state,
               struct acpi_namespace_node **return_node)
{
        acpi_status status;
        char *path = pathname;
        char *external_path;
        struct acpi_namespace_node *prefix_node;
        struct acpi_namespace_node *current_node = NULL;
        struct acpi_namespace_node *this_node = NULL;
        u32 num_segments;
        u32 num_carats;
        acpi_name simple_name;
        acpi_object_type type_to_check_for;
        acpi_object_type this_search_type;
        u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
        u32 local_flags;
        acpi_interpreter_mode local_interpreter_mode;

        ACPI_FUNCTION_TRACE(ns_lookup);

        if (!return_node) {
                return_ACPI_STATUS(AE_BAD_PARAMETER);
        }

        local_flags = flags &
            ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
              ACPI_NS_SEARCH_PARENT);
        *return_node = ACPI_ENTRY_NOT_FOUND;
        acpi_gbl_ns_lookup_count++;

        if (!acpi_gbl_root_node) {
                return_ACPI_STATUS(AE_NO_NAMESPACE);
        }

        /* Get the prefix scope. A null scope means use the root scope */

        if ((!scope_info) || (!scope_info->scope.node)) {
                ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                  "Null scope prefix, using root node (%p)\n",
                                  acpi_gbl_root_node));

                prefix_node = acpi_gbl_root_node;
        } else {
                prefix_node = scope_info->scope.node;
                if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
                    ACPI_DESC_TYPE_NAMED) {
                        ACPI_ERROR((AE_INFO, "%p is not a namespace node [%s]",
                                    prefix_node,
                                    acpi_ut_get_descriptor_name(prefix_node)));
                        return_ACPI_STATUS(AE_AML_INTERNAL);
                }

                if (!(flags & ACPI_NS_PREFIX_IS_SCOPE)) {
                        /*
                         * This node might not be a actual "scope" node (such as a
                         * Device/Method, etc.)  It could be a Package or other object
                         * node. Backup up the tree to find the containing scope node.
                         */
                        while (!acpi_ns_opens_scope(prefix_node->type) &&
                               prefix_node->type != ACPI_TYPE_ANY) {
                                prefix_node = prefix_node->parent;
                        }
                }
        }

        /* Save type. TBD: may be no longer necessary */

        type_to_check_for = type;

        /*
         * Begin examination of the actual pathname
         */
        if (!pathname) {

                /* A Null name_path is allowed and refers to the root */

                num_segments = 0;
                this_node = acpi_gbl_root_node;
                path = "";

                ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                  "Null Pathname (Zero segments), Flags=%X\n",
                                  flags));
        } else {
                /*
                 * Name pointer is valid (and must be in internal name format)
                 *
                 * Check for scope prefixes:
                 *
                 * As represented in the AML stream, a namepath consists of an
                 * optional scope prefix followed by a name segment part.
                 *
                 * If present, the scope prefix is either a Root Prefix (in
                 * which case the name is fully qualified), or one or more
                 * Parent Prefixes (in which case the name's scope is relative
                 * to the current scope).
                 */
                if (*path == (u8) AML_ROOT_PREFIX) {

                        /* Pathname is fully qualified, start from the root */

                        this_node = acpi_gbl_root_node;
                        search_parent_flag = ACPI_NS_NO_UPSEARCH;

                        /* Point to name segment part */

                        path++;

                        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                          "Path is absolute from root [%p]\n",
                                          this_node));
                } else {
                        /* Pathname is relative to current scope, start there */

                        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                          "Searching relative to prefix scope [%4.4s] (%p)\n",
                                          acpi_ut_get_node_name(prefix_node),
                                          prefix_node));

                        /*
                         * Handle multiple Parent Prefixes (carat) by just getting
                         * the parent node for each prefix instance.
                         */
                        this_node = prefix_node;
                        num_carats = 0;
                        while (*path == (u8) AML_PARENT_PREFIX) {

                                /* Name is fully qualified, no search rules apply */

                                search_parent_flag = ACPI_NS_NO_UPSEARCH;

                                /*
                                 * Point past this prefix to the name segment
                                 * part or the next Parent Prefix
                                 */
                                path++;

                                /* Backup to the parent node */

                                num_carats++;
                                this_node = this_node->parent;
                                if (!this_node) {
                                        /*
                                         * Current scope has no parent scope. Externalize
                                         * the internal path for error message.
                                         */
                                        status =
                                            acpi_ns_externalize_name
                                            (ACPI_UINT32_MAX, pathname, NULL,
                                             &external_path);
                                        if (ACPI_SUCCESS(status)) {
                                                ACPI_ERROR((AE_INFO,
                                                            "%s: Path has too many parent prefixes (^)",
                                                            external_path));

                                                ACPI_FREE(external_path);
                                        }

                                        return_ACPI_STATUS(AE_NOT_FOUND);
                                }
                        }

                        if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
                                ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                                  "Search scope is [%4.4s], path has %u carat(s)\n",
                                                  acpi_ut_get_node_name
                                                  (this_node), num_carats));
                        }
                }

                /*
                 * Determine the number of ACPI name segments in this pathname.
                 *
                 * The segment part consists of either:
                 *  - A Null name segment (0)
                 *  - A dual_name_prefix followed by two 4-byte name segments
                 *  - A multi_name_prefix followed by a byte indicating the
                 *      number of segments and the segments themselves.
                 *  - A single 4-byte name segment
                 *
                 * Examine the name prefix opcode, if any, to determine the number of
                 * segments.
                 */
                switch (*path) {
                case 0:
                        /*
                         * Null name after a root or parent prefixes. We already
                         * have the correct target node and there are no name segments.
                         */
                        num_segments = 0;
                        type = this_node->type;

                        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                          "Prefix-only Pathname (Zero name segments), Flags=%X\n",
                                          flags));
                        break;

                case AML_DUAL_NAME_PREFIX:

                        /* More than one name_seg, search rules do not apply */

                        search_parent_flag = ACPI_NS_NO_UPSEARCH;

                        /* Two segments, point to first name segment */

                        num_segments = 2;
                        path++;

                        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                          "Dual Pathname (2 segments, Flags=%X)\n",
                                          flags));
                        break;

                case AML_MULTI_NAME_PREFIX:

                        /* More than one name_seg, search rules do not apply */

                        search_parent_flag = ACPI_NS_NO_UPSEARCH;

                        /* Extract segment count, point to first name segment */

                        path++;
                        num_segments = (u32) (u8) * path;
                        path++;

                        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                          "Multi Pathname (%u Segments, Flags=%X)\n",
                                          num_segments, flags));
                        break;

                default:
                        /*
                         * Not a Null name, no Dual or Multi prefix, hence there is
                         * only one name segment and Pathname is already pointing to it.
                         */
                        num_segments = 1;

                        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                          "Simple Pathname (1 segment, Flags=%X)\n",
                                          flags));
                        break;
                }

                ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
        }

        /*
         * Search namespace for each segment of the name. Loop through and
         * verify (or add to the namespace) each name segment.
         *
         * The object type is significant only at the last name
         * segment. (We don't care about the types along the path, only
         * the type of the final target object.)
         */
        this_search_type = ACPI_TYPE_ANY;
        current_node = this_node;

        while (num_segments && current_node) {
                num_segments--;
                if (!num_segments) {

                        /* This is the last segment, enable typechecking */

                        this_search_type = type;

                        /*
                         * Only allow automatic parent search (search rules) if the caller
                         * requested it AND we have a single, non-fully-qualified name_seg
                         */
                        if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
                            (flags & ACPI_NS_SEARCH_PARENT)) {
                                local_flags |= ACPI_NS_SEARCH_PARENT;
                        }

                        /* Set error flag according to caller */

                        if (flags & ACPI_NS_ERROR_IF_FOUND) {
                                local_flags |= ACPI_NS_ERROR_IF_FOUND;
                        }

                        /* Set override flag according to caller */

                        if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
                                local_flags |= ACPI_NS_OVERRIDE_IF_FOUND;
                        }
                }

                /* Handle opcodes that create a new name_seg via a full name_path */

                local_interpreter_mode = interpreter_mode;
                if ((flags & ACPI_NS_PREFIX_MUST_EXIST) && (num_segments > 0)) {

                        /* Every element of the path must exist (except for the final name_seg) */

                        local_interpreter_mode = ACPI_IMODE_EXECUTE;
                }

                /* Extract one ACPI name from the front of the pathname */

                ACPI_MOVE_32_TO_32(&simple_name, path);

                /* Try to find the single (4 character) ACPI name */

                status =
                    acpi_ns_search_and_enter(simple_name, walk_state,
                                             current_node,
                                             local_interpreter_mode,
                                             this_search_type, local_flags,
                                             &this_node);
                if (ACPI_FAILURE(status)) {
                        if (status == AE_NOT_FOUND) {
#if !defined ACPI_ASL_COMPILER  /* Note: iASL reports this error by itself, not needed here */
                                if (flags & ACPI_NS_PREFIX_MUST_EXIST) {
                                        acpi_os_printf(ACPI_MSG_BIOS_ERROR
                                                       "Object does not exist: %4.4s\n",
                                                       &simple_name);
                                }
#endif
                                /* Name not found in ACPI namespace */

                                ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
                                                  "Name [%4.4s] not found in scope [%4.4s] %p\n",
                                                  (char *)&simple_name,
                                                  (char *)&current_node->name,
                                                  current_node));
                        }
#ifdef ACPI_EXEC_APP
                        if ((status == AE_ALREADY_EXISTS) &&
                            (this_node->flags & ANOBJ_NODE_EARLY_INIT)) {
                                this_node->flags &= ~ANOBJ_NODE_EARLY_INIT;
                                status = AE_OK;
                        }
#endif

#ifdef ACPI_ASL_COMPILER
                        /*
                         * If this ACPI name already exists within the namespace as an
                         * external declaration, then mark the external as a conflicting
                         * declaration and proceed to process the current node as if it did
                         * not exist in the namespace. If this node is not processed as
                         * normal, then it could cause improper namespace resolution
                         * by failing to open a new scope.
                         */
                        if (acpi_gbl_disasm_flag &&
                            (status == AE_ALREADY_EXISTS) &&
                            ((this_node->flags & ANOBJ_IS_EXTERNAL) ||
                             (walk_state
                              && walk_state->opcode == AML_EXTERNAL_OP))) {
                                this_node->flags &= ~ANOBJ_IS_EXTERNAL;
                                this_node->type = (u8)this_search_type;
                                if (walk_state->opcode != AML_EXTERNAL_OP) {
                                        acpi_dm_mark_external_conflict
                                            (this_node);
                                }
                                break;
                        }
#endif

                        *return_node = this_node;
                        return_ACPI_STATUS(status);
                }

                /* More segments to follow? */

                if (num_segments > 0) {
                        /*
                         * If we have an alias to an object that opens a scope (such as a
                         * device or processor), we need to dereference the alias here so
                         * that we can access any children of the original node (via the
                         * remaining segments).
                         */
                        if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
                                if (!this_node->object) {
                                        return_ACPI_STATUS(AE_NOT_EXIST);
                                }

                                if (acpi_ns_opens_scope
                                    (((struct acpi_namespace_node *)
                                      this_node->object)->type)) {
                                        this_node =
                                            (struct acpi_namespace_node *)
                                            this_node->object;
                                }
                        }
                }

                /* Special handling for the last segment (num_segments == 0) */

                else {
                        /*
                         * Sanity typecheck of the target object:
                         *
                         * If 1) This is the last segment (num_segments == 0)
                         *    2) And we are looking for a specific type
                         *       (Not checking for TYPE_ANY)
                         *    3) Which is not an alias
                         *    4) Which is not a local type (TYPE_SCOPE)
                         *    5) And the type of target object is known (not TYPE_ANY)
                         *    6) And target object does not match what we are looking for
                         *
                         * Then we have a type mismatch. Just warn and ignore it.
                         */
                        if ((type_to_check_for != ACPI_TYPE_ANY) &&
                            (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
                            (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
                            && (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
                            && (this_node->type != ACPI_TYPE_ANY)
                            && (this_node->type != type_to_check_for)) {

                                /* Complain about a type mismatch */

                                ACPI_WARNING((AE_INFO,
                                              "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
                                              ACPI_CAST_PTR(char, &simple_name),
                                              acpi_ut_get_type_name(this_node->
                                                                    type),
                                              acpi_ut_get_type_name
                                              (type_to_check_for)));
                        }

                        /*
                         * If this is the last name segment and we are not looking for a
                         * specific type, but the type of found object is known, use that
                         * type to (later) see if it opens a scope.
                         */
                        if (type == ACPI_TYPE_ANY) {
                                type = this_node->type;
                        }
                }

                /* Point to next name segment and make this node current */

                path += ACPI_NAMESEG_SIZE;
                current_node = this_node;
        }

        /* Always check if we need to open a new scope */

        if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
                /*
                 * If entry is a type which opens a scope, push the new scope on the
                 * scope stack.
                 */
                if (acpi_ns_opens_scope(type)) {
                        status =
                            acpi_ds_scope_stack_push(this_node, type,
                                                     walk_state);
                        if (ACPI_FAILURE(status)) {
                                return_ACPI_STATUS(status);
                        }
                }
        }
#ifdef ACPI_EXEC_APP
        if (flags & ACPI_NS_EARLY_INIT) {
                this_node->flags |= ANOBJ_NODE_EARLY_INIT;
        }
#endif

        *return_node = this_node;
        return_ACPI_STATUS(AE_OK);
}