[Kernel] Change command line to const parameter and add system() function.

components/finsh/msh.c

@@ -180,7 +180,7 @@ static cmd_function_t msh_get_cmd(char *cmd, int size)
 #if defined(RT_USING_MODULE) && defined(RT_USING_DFS)
 /* Return 0 on module executed. Other value indicate error.
  */
-int msh_exec_module(char* cmd_line, int size)
+int msh_exec_module(const char* cmd_line, int size)
 {
     int ret;
     int fd = -1;
@@ -248,6 +248,11 @@ int msh_exec_module(char* cmd_line, int size)
     rt_free(pg_name);
     return ret;
 }
+
+int system(const char *command)
+{
+    return msh_exec_module(command, rt_strlen(command));
+}
 #endif
 
 static int _msh_exec_cmd(char* cmd, rt_size_t length, int *retp)
@@ -346,8 +351,8 @@ static int str_common(const char *str1, const char *str2)
 #ifdef RT_USING_DFS
 void msh_auto_complete_path(char *path)
 {
-    DIR* dir;
-    struct dirent *dirent;
+    DIR* dir = RT_NULL;
+    struct dirent *dirent = RT_NULL;
     char *full_path, *ptr, *index;
 
     full_path = (char*)rt_malloc(256);

include/rtthread.h

@@ -421,7 +421,7 @@ rt_module_t rt_module_load(const char *name, void *module_ptr);
 rt_err_t rt_module_unload(rt_module_t module);
 #ifdef RT_USING_DFS
 rt_module_t rt_module_open(const char *filename);
-rt_module_t rt_module_exec_cmd(const char *path, char* cmd_line, int size);
+rt_module_t rt_module_exec_cmd(const char *path, const char* cmd_line, int size);
 #endif
 void *rt_module_malloc(rt_size_t size);
 void *rt_module_realloc(void *ptr, rt_size_t size);

src/module.c

@@ -920,7 +920,7 @@ static void module_main_entry(void* parameter)
  *
  * @return the module object
  */
-rt_module_t rt_module_do_main(const char *name, void *module_ptr, char* cmd_line, int line_size)
+rt_module_t rt_module_do_main(const char *name, void *module_ptr, const char* cmd_line, int line_size)
 {
 	rt_module_t module;
 
@@ -1125,7 +1125,7 @@ rt_module_t rt_module_open(const char *path)
  *
  * @return the module object
  */
-rt_module_t rt_module_exec_cmd(const char *path, char* cmd_line, int size)
+rt_module_t rt_module_exec_cmd(const char *path, const char* cmd_line, int size)
 {
     struct stat s;
     int fd, length;