/**************************************************************************** * libs/libc/dlfcn/lib_dlclose.c * * Copyright (C) 2017 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #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); /* 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 */ 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 * 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 }