2017-01-22 16:14:18 +01:00
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/****************************************************************************
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2019-02-09 21:09:28 +01:00
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* libs/libc/dlfcn/lib_dlsym.c
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2017-01-22 16:14:18 +01:00
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*
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2021-03-02 15:54:21 +01:00
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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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2017-01-22 16:14:18 +01:00
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*
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2021-03-02 15:54:21 +01:00
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* http://www.apache.org/licenses/LICENSE-2.0
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2017-01-22 16:14:18 +01:00
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*
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2021-03-02 15:54:21 +01:00
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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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2017-01-22 16:14:18 +01:00
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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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2019-02-09 21:09:28 +01:00
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#include <dlfcn.h>
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2021-05-18 08:59:14 +02:00
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#include <assert.h>
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2021-05-14 04:45:57 +02:00
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#include <debug.h>
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2017-01-29 20:03:53 +01:00
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#include <errno.h>
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2017-01-22 16:14:18 +01:00
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2017-01-22 22:33:19 +01:00
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#include <nuttx/module.h>
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2017-01-29 20:03:53 +01:00
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#include <nuttx/symtab.h>
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#include <nuttx/lib/modlib.h>
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: dlgetsym
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*
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* Description:
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* dlgetsym() implements dlsym() for the PROTECTED build.
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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 insmod().
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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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* See dlsym().
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*
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****************************************************************************/
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#ifdef CONFIG_BUILD_PROTECTED
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static inline FAR const void *dlgetsym(FAR void *handle,
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FAR const char *name)
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{
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FAR struct module_s *modp = (FAR struct module_s *)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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serr("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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serr("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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if (symbol == NULL)
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{
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2019-01-26 18:39:05 +01:00
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serr("ERROR: Failed to find symbol in symbol \"%s\" in table\n", name);
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2017-01-29 20:03:53 +01:00
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err = ENOENT;
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goto errout_with_lock;
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}
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2019-01-26 18:39:05 +01:00
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/* Return the address within the module associated with the symbol */
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2017-01-29 20:03:53 +01:00
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modlib_registry_unlock();
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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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#endif
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2017-01-22 22:33:19 +01:00
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2017-01-22 16:14:18 +01:00
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: dlsym
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*
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* Description:
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* dlsym() allows a process to obtain the address of a symbol defined
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* within an object made accessible through a dlopen() call. handle is the
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* value returned from a call to dlopen() (and which has not since been
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* released via a call to dlclose()), name is the symbol's name as a
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* character string.
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*
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* dlsym() will search for the named symbol in all objects loaded
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* automatically as a result of loading the object referenced by handle
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* (see dlopen()). Load ordering is used in dlsym() operations upon the
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* global symbol object. The symbol resolution algorithm used will be
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* dependency order as described in dlopen().
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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 dlopen().
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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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* If handle does not refer to a valid object opened by dlopen(), or if
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* the named symbol cannot be found within any of the objects associated
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* with handle, dlsym() will return NULL. More detailed diagnostic
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* information will be available through dlerror().
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*
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* Reference: OpenGroup.org
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*
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****************************************************************************/
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FAR void *dlsym(FAR void *handle, FAR const char *name)
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{
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2017-01-22 22:33:19 +01:00
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#if defined(CONFIG_BUILD_FLAT)
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/* In the FLAT build, a shared library is essentially the same as a kernel
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* module.
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*/
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return (FAR void *)modsym(handle, name);
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#elif defined(CONFIG_BUILD_PROTECTED)
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/* The PROTECTED build is equivalent to the FLAT build EXCEPT that there
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2017-01-29 14:52:44 +01:00
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* must be two copies of the module logic: One residing in kernel
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2017-01-22 22:33:19 +01:00
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* space and using the kernel symbol table and one residing in user space
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* using the user space symbol table.
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*
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2017-01-29 20:03:53 +01:00
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* dlgetsem() is essentially a clone of modsym().
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2017-01-22 22:33:19 +01:00
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*/
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2017-01-29 20:03:53 +01:00
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return (FAR void *)dlgetsym(handle, name);
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2017-01-22 22:33:19 +01:00
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#else /* if defined(CONFIG_BUILD_KERNEL) */
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/* The KERNEL build is considerably more complex: In order to be shared,
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* the .text portion of the module must be (1) build for PIC/PID operation
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* and (2) must like in a shared memory region accessible from all
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* processes. The .data/.bss portion of the module must be allocated in
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* the user space of each process, but must lie at the same virtual address
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* so that it can be referenced from the one copy of the text in the shared
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* memory region.
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*/
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2017-01-22 16:14:18 +01:00
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#warning Missing logic
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return NULL;
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2017-01-22 22:33:19 +01:00
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#endif
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2017-01-29 14:52:44 +01:00
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}
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