117 lines
3.9 KiB
C
117 lines
3.9 KiB
C
/****************************************************************************
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* libs/libc/modlib/modlib_getsymbol.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <assert.h>
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#include <debug.h>
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#include <errno.h>
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#include <nuttx/lib/modlib.h>
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#include <nuttx/symtab.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: modlib_getsymbol
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*
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* Description:
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* modlib_getsymbol() returns the address of a symbol defined within the
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* object that was previously made accessible through a modlib_getsymbol()
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* call. handle is the value returned from a call to modlib_insert() (and
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* which has not since been released via a call to modlib_remove()),
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* name is the symbol's name as a character string.
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*
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* The returned symbol address will remain valid until modlib_remove() is
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* called.
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*
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* Input Parameters:
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* handle - The opaque, non-NULL value returned by a previous successful
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* call to modlib_insert().
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* name - A pointer to the symbol name string.
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*
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* Returned Value:
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* The address associated with the symbol is returned on success.
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* If handle does not refer to a valid module opened by modlib_insert(),
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* or if the named modlib_symbol cannot be found within any of the objects
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* associated with handle, modlib_getsymbol() will return NULL and the
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* errno variable will be set appropriately.
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*
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* NOTE: This means that the address zero can never be a valid return
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* value.
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*
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****************************************************************************/
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FAR const void *modlib_getsymbol(FAR void *handle, FAR const char *name)
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{
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FAR struct module_s *modp = handle;
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FAR const struct symtab_s *symbol;
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int err;
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int ret;
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/* Verify that the module is in the registry */
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modlib_registry_lock();
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ret = modlib_registry_verify(modp);
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if (ret < 0)
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{
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berr("ERROR: Failed to verify module: %d\n", ret);
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err = -ret;
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goto errout_with_lock;
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}
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/* Does the module have a symbol table? */
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if (modp->modinfo.exports == NULL || modp->modinfo.nexports == 0)
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{
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berr("ERROR: Module has no symbol table\n");
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err = ENOENT;
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goto errout_with_lock;
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}
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/* Search the symbol table for the matching symbol */
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symbol = symtab_findbyname(modp->modinfo.exports, name,
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modp->modinfo.nexports);
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modlib_registry_unlock();
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if (symbol == NULL)
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{
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berr("ERROR: Failed to find symbol in symbol \"%s\" in table\n", name);
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set_errno(ENOENT);
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return NULL;
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}
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/* Return the address within the module associated with the symbol */
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DEBUGASSERT(symbol->sym_value != NULL);
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return symbol->sym_value;
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errout_with_lock:
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modlib_registry_unlock();
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set_errno(err);
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return NULL;
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}
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