nuttx/libs/libc/dlfcn/lib_dlclose.c

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/****************************************************************************
* libs/libc/dlfcn/lib_dlclose.c
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <dlfcn.h>
#include <errno.h>
#include <nuttx/module.h>
#include <nuttx/lib/modlib.h>
#include "libc.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: dlremove
*
* Description:
* Remove a previously installed shared library from memory.
*
* Input Parameters:
* handle - The shared library handle previously returned by dlopen().
*
* Returned Value:
* Zero (OK) on success. On any failure, -1 (ERROR) is returned the
* errno value is set appropriately.
*
****************************************************************************/
#ifdef CONFIG_BUILD_PROTECTED
static inline int dlremove(FAR void *handle)
{
FAR struct module_s *modp = (FAR struct module_s *)handle;
int ret;
DEBUGASSERT(modp != NULL);
/* Get exclusive access to the module registry */
modlib_registry_lock();
/* Verify that the module is in the registry */
ret = modlib_registry_verify(modp);
if (ret < 0)
{
serr("ERROR: Failed to verify module: %d\n", ret);
goto errout_with_lock;
}
#if CONFIG_MODLIB_MAXDEPEND > 0
/* Refuse to remove any module that other modules may depend upon. */
if (modp->dependents > 0)
{
serr("ERROR: Module has dependents: %d\n", modp->dependents);
ret = -EBUSY;
goto errout_with_lock;
}
#endif
/* Is there an uninitializer? */
if (modp->modinfo.uninitializer != NULL)
{
/* Try to uninitialize the module */
ret = modp->modinfo.uninitializer(modp->modinfo.arg);
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/* Did the module successfully uninitialize? */
if (ret < 0)
{
serr("ERROR: Failed to uninitialize the module: %d\n", ret);
goto errout_with_lock;
}
/* Nullify so that the uninitializer cannot be called again */
modp->modinfo.uninitializer = NULL;
#if defined(CONFIG_FS_PROCFS) && !defined(CONFIG_FS_PROCFS_EXCLUDE_MODULE)
modp->initializer = NULL;
modp->modinfo.arg = NULL;
modp->modinfo.exports = NULL;
modp->modinfo.nexports = 0;
#endif
}
/* Release resources held by the module */
if (modp->alloc != NULL)
{
/* Free the module memory */
lib_free((FAR void *)modp->alloc);
/* Nullify so that the memory cannot be freed again */
modp->alloc = NULL;
#if defined(CONFIG_FS_PROCFS) && !defined(CONFIG_FS_PROCFS_EXCLUDE_MODULE)
modp->textsize = 0;
modp->datasize = 0;
#endif
}
/* Remove the module from the registry */
ret = modlib_registry_del(modp);
if (ret < 0)
{
serr("ERROR: Failed to remove the module from the registry: %d\n", ret);
goto errout_with_lock;
}
#if CONFIG_MODLIB_MAXDEPEND > 0
/* Eliminate any dependencies that this module has on other modules */
(void)modlib_undepend(modp);
#endif
modlib_registry_unlock();
/* And free the registry entry */
lib_free(modp);
return OK;
errout_with_lock:
modlib_registry_unlock();
set_errno(-ret);
return ERROR;
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: dlclose
*
* Description:
* dlclose() is used to inform the system that the object referenced by a
* handle returned from a previous dlopen() invocation is no longer needed
* by the application.
*
* The use of dlclose() reflects a statement of intent on the part of the
* process, but does not create any requirement upon the implementation,
* such as removal of the code or symbols referenced by handle. Once an
* object has been closed using dlclose() an application should assume
* that its symbols are no longer available to dlsym(). All objects loaded
* automatically as a result of invoking dlopen() on the referenced object
* are also closed.
*
* Although a dlclose() operation is not required to remove structures
* from an address space, neither is an implementation prohibited from
* doing so. The only restriction on such a removal is that no object will
* be removed to which references have been relocated, until or unless all
* such references are removed. For instance, an object that had been
* loaded with a dlopen() operation specifying the RTLD_GLOBAL flag might
* provide a target for dynamic relocations performed in the processing of
* other objects - in such environments, an application may assume that no
* relocation, once made, will be undone or remade unless the object
* requiring the relocation has itself been removed.
*
* Input Parameters:
* handle - The opaque, non-NULL value returned by a previous successful
* call to dlopen().
*
* Returned Value:
* If the referenced object was successfully closed, dlclose() returns 0.
* If the object could not be closed, or if handle does not refer to an
* open object, dlclose() returns a non-zero value. More detailed
* diagnostic information will be available through dlerror().
*
* Reference: OpenGroup.org
*
****************************************************************************/
int dlclose(FAR void *handle)
{
#if defined(CONFIG_BUILD_FLAT)
/* In the FLAT build, a shared library is essentially the same as a kernel
* module.
*/
return rmmod(handle);
#elif defined(CONFIG_BUILD_PROTECTED)
/* The PROTECTED build is equivalent to the FLAT build EXCEPT that there
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* must be two copies of the module logic: One residing in kernel
* space and using the kernel symbol table and one residing in user space
* using the user space symbol table.
*
* dlremove() is essentially a clone of rmmod().
*/
return dlremove(handle);
#else /* if defined(CONFIG_BUILD_KERNEL) */
/* The KERNEL build is considerably more complex: In order to be shared,
* the .text portion of the module must be (1) build for PIC/PID operation
* and (2) must like in a shared memory region accessible from all
* processes. The .data/.bss portion of the module must be allocated in
* the user space of each process, but must lie at the same virtual address
* so that it can be referenced from the one copy of the text in the shared
* memory region.
*/
#warning Missing logic
return -ENOSYS;
#endif
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}