first commit for chrg

2025-08-16 22:58:22 +08:00
commit 52a3ed5862
2306 changed files with 1021208 additions and 0 deletions
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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;
+
+    /* 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 */
+    }
+
+    rt_enter_critical();
+
+    /* find in module list */
+    module = dlmodule_find(fullpath);
+
+    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);