unable to use sys_calls (like open etc.) in module code

mushudubi · 01-03-2006, 02:48 AM

Hi,
when trying to program kernel module I can't use sys_calls like open(), read() etc. in my code.
I include the following files:

#define __KERNEL_SYSCALLS__
#include <linux/version.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/smp_lock.h>
#include <linux/sched.h>
#include <linux/unistd.h>
#include <linux/string.h>
#include <linux/file.h>
#include <asm/uaccess.h>
#include <linux/proc_fs.h>
#include <asm/errno.h>
#include <asm/io.h>

my Makefile looks like this:

obj-m += my_code.o
all:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) cleans:

and when I do make the following warning is shown:
"warning: implicit declaration of function `open'"
--------------------------------------------------

How can I overcome this?
I am using FEDORA core 2.6.11

thanks.

foo_bar_foo · 01-03-2006, 10:04 PM

i think there might be a way to use userspace syscalls inside the kernel but it's wastefull
better to use internal functions like

Code:

#include < linux/fs.h>
struct file *fp;
fp = filp_open("/some/file", O_RDONLY, 0);
filp_close(fp, NULL);

how to figure it out is look in fs/open.c at sys_open() to see how it's implemented and there you find

Code:

struct file *f = filp_open(tmp, flags, mode);

there you go
couldn't be easier