Use sys_open from kernel level

Question

Hi i am having some trouble using sys_open.At this point i am starting to think that i am doing something wrong with the arguments of the functions. An example of how i use it:

fd = sys_open("file.txt" , O_WRONLY | O_CREAT, 0);
sys_write(fd, "test\n", strlen("test\n"));
sys_fsync(fd);
sys_fdatasync(fd);
sys_close(fd);

fd value is a non negative integer (0). Every single one of the functions returns 0 so i guess they are executed corectly.Except sys_write. Every time that i go to find the file after i write on it i can never find it any idea maybe something on my code is wrong?

Answer 1

The sys_ family of functions for Linux are considered deprecated now . However, for the purposes of this question, sys_open is a user-level function that calls the open syscall, which then calls the kernel level do_sys_open() , the latter two defined in fs/open.c . So to open files from within the kernel you should stick to kernel level functions and not user-level functions.

Here are some answers about opening files at the kernel level, some of which are deprecated as well, so be aware.