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/*
* Copyright (c) 2006-2024 RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2010-11-17 yi.qiu first version
*/
#include <rtthread.h>
#include <rtm.h>
#include <string.h>
#include "dlmodule.h"
#define MODULE_ROOT_DIR "/modules"
/**
* @brief dynamically load a shared library at runtime.
*
* @param filename the path to the shared library to load, which shouldn't be set to NULL.
* @param flags options for loading the shared library.
* @return void* on success, it returns a handle (a pointer) to the opened shared library, otherwise it returns NULL.
*
* @note This function is an API of POSIX standard, which is used for dynamically loading shared libraries at runtime.
* the function first tries to check if the module is already loaded, by finding module in module list.
* If module is found in memory (RT_NULL check fails), the reference count (nref) is incremented.
* Otherwise, dlmodule_load() will be called to load the module into memory.
* A handle (a pointer to the module) is returned at last, which can be used with other functions like dlsym().
*/
void* dlopen(const char *filename, int flags)
{
struct rt_dlmodule *module;
char *fullpath;
const char *def_path = MODULE_ROOT_DIR;
char module_name[RT_NAME_MAX];
/* check parameters */
RT_ASSERT(filename != RT_NULL);
if (filename[0] != '/') /* it's a relative path, prefix with MODULE_ROOT_DIR */
{
fullpath = rt_malloc(strlen(def_path) + strlen(filename) + 2);
/* join path and file name */
rt_snprintf(fullpath, strlen(def_path) + strlen(filename) + 2,
"%s/%s", def_path, filename);
}
else
{
fullpath = (char *)filename; /* absolute path, use it directly */
}
/* Extract module name from path (strip directory and extension)
* This matches the logic in _dlmodule_set_name() so that dlmodule_find()
* can properly locate already-loaded modules by their stored name.
*/
dlmodule_extract_name(fullpath, module_name, RT_NAME_MAX);
rt_enter_critical();
/* find in module list using the stripped module name */
module = dlmodule_find(module_name);
if (module != RT_NULL)
{
rt_exit_critical();
module->nref++;
}
else
{
rt_exit_critical();
module = dlmodule_load(fullpath);
}
if (fullpath != filename)
{
rt_free(fullpath);
}
return (void *)module;
}
RTM_EXPORT(dlopen);
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