Errors in making Kernel module

shaaraddalvi · 02-09-2013, 02:13 AM

I have a sample code for kernel module, which when I try to compile I am continuously getting errors.

Code:

/* 
 *  kbleds.c − Blink keyboard leds until the module is unloaded.
 */
#include <linux/module.h>
#include <linux/config.h>
#include <linux/init.h>
#include <linux/tty.h>          /* For fg_console, MAX_NR_CONSOLES */
#include <linux/kd.h>           /* For KDSETLED */
#include <linux/vt.h>
#include <linux/console_struct.h>       /* For vc_cons */
MODULE_DESCRIPTION("Example module illustrating the use of Keyboard LEDs.");
MODULE_AUTHOR("Daniele Paolo Scarpazza");
MODULE_LICENSE("GPL");
struct timer_list my_timer;
struct tty_driver *my_driver;
char kbledstatus = 0;
#define BLINK_DELAY   HZ/5
#define ALL_LEDS_ON   0x07
#define RESTORE_LEDS  0xFF
/*
 * Function my_timer_func blinks the keyboard LEDs periodically by invoking
 * command KDSETLED of ioctl() on the keyboard driver. To learn more on virtual 
 * terminal ioctl operations, please see file:
 *     /usr/src/linux/drivers/char/vt_ioctl.c, function vt_ioctl().
 *
 * The argument to KDSETLED is alternatively set to 7 (thus causing the led 
 * mode to be set to LED_SHOW_IOCTL, and all the leds are lit) and to 0xFF
 * (any value above 7 switches back the led mode to LED_SHOW_FLAGS, thus
 * the LEDs reflect the actual keyboard status).  To learn more on this, 
 * please see file:
 *     /usr/src/linux/drivers/char/keyboard.c, function setledstate().
 * 
 */
static void my_timer_func(unsigned long ptr)
{
        int *pstatus = (int *)ptr;
		if (*pstatus == ALL_LEDS_ON)
                *pstatus = RESTORE_LEDS;
        else
                *pstatus = ALL_LEDS_ON;
        (my_driver−>ioctl) (vc_cons[fg_console].d−>vc_tty, NULL, KDSETLED,
                            *pstatus);
        my_timer.expires = jiffies + BLINK_DELAY;
        add_timer(&my_timer);
}
static int __init kbleds_init(void)
{
        int i;
        printk(KERN_INFO "kbleds: loading\n");
        printk(KERN_INFO "kbleds: fgconsole is %x\n", fg_console);
        for (i = 0; i < MAX_NR_CONSOLES; i++) {
                if (!vc_cons[i].d)
                        break;
                printk(KERN_INFO "poet_atkm: console[%i/%i] #%i, tty %lx\n", i,
                       MAX_NR_CONSOLES, vc_cons[i].d−>vc_num,
                       (unsigned long)vc_cons[i].d−>vc_tty);
        }
        printk(KERN_INFO "kbleds: finished scanning consoles\n");
        my_driver = vc_cons[fg_console].d−>vc_tty−>driver;
        printk(KERN_INFO "kbleds: tty driver magic %x\n", my_driver−>magic);
        /*
         * Set up the LED blink timer the first time
         */
        init_timer(&my_timer);
        my_timer.function = my_timer_func;
        my_timer.data = (unsigned long)&kbledstatus;
        my_timer.expires = jiffies + BLINK_DELAY;
        add_timer(&my_timer);
        return 0;
}
static void __exit kbleds_cleanup(void)
{
        printk(KERN_INFO "kbleds: unloading...\n");
        del_timer(&my_timer);
        (my_driver−>ioctl) (vc_cons[fg_console].d−>vc_tty, NULL, KDSETLED,
                            RESTORE_LEDS);
}
module_init(kbleds_init);
module_exit(kbleds_cleanup);

Why does it say that config.h is not found??

knudfl · 02-09-2013, 02:55 AM

No "config.h" any more in a contemporary kernel.
But you can make one :

cd /usr/src///<linux>//include/linux/
# ln -s ../generated/autoconf.h config.h

shaaraddalvi · 02-09-2013, 03:35 AM

Thanks a lot!
Yes, that solved the problem of config.h not found, but now it is giving a bunch of errors like :

Code:

home/shaarad/Study/Linux/modtests/kbleds.c: In function ‘my_timer_func’:
/home/shaarad/Study/Linux/modtests/kbleds.c:42:9: error: stray ‘\342’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:42:9: error: stray ‘\210’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:42:9: error: stray ‘\222’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:42:23: error: ‘ioctl’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c:42:23: note: each undeclared identifier is reported only once for each function it appears in
/home/shaarad/Study/Linux/modtests/kbleds.c:42:39: error: ‘fg_console’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c:42:9: error: stray ‘\342’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:42:9: error: stray ‘\210’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:42:9: error: stray ‘\222’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:42:56: error: ‘vc_tty’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c: In function ‘kbleds_init’:
/home/shaarad/Study/Linux/modtests/kbleds.c:51:55: error: ‘fg_console’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c:56:24: error: stray ‘\342’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:56:24: error: stray ‘\210’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:56:24: error: stray ‘\222’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:56:57: error: ‘vc_num’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c:57:24: error: stray ‘\342’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:57:24: error: stray ‘\210’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:57:24: error: stray ‘\222’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:57:55: error: ‘vc_tty’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c:60:9: error: stray ‘\342’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:60:9: error: stray ‘\210’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:60:9: error: stray ‘\222’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:60:9: error: stray ‘\342’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:60:9: error: stray ‘\210’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:60:9: error: stray ‘\222’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:60:56: error: ‘driver’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c:61:9: error: stray ‘\342’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:61:9: error: stray ‘\210’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:61:9: error: stray ‘\222’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:61:72: error: ‘magic’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c: In function ‘kbleds_cleanup’:
/home/shaarad/Study/Linux/modtests/kbleds.c:76:9: error: stray ‘\342’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:76:9: error: stray ‘\210’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:76:9: error: stray ‘\222’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:76:23: error: ‘ioctl’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c:76:39: error: ‘fg_console’ undeclared (first use in this function)
/home/shaarad/Study/Linux/modtests/kbleds.c:76:9: error: stray ‘\342’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:76:9: error: stray ‘\210’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:76:9: error: stray ‘\222’ in program
/home/shaarad/Study/Linux/modtests/kbleds.c:76:56: error: ‘vc_tty’ undeclared (first use in this function)
make[2]: *** [/home/shaarad/Study/Linux/modtests/kbleds.o] Error 1
make[1]: *** [_module_/home/shaarad/Study/Linux/modtests] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-3.2.0-29-generic'
make: *** [all] Error 2

knudfl · 02-09-2013, 04:08 AM

? Looks like you found "kbleds.c" here ..
http://www.tldp.org/LDP/lkmpg/2.6/ht...g.html#AEN1201
.. Latest update was '18 May 2007' : It's old code.
Quote : "2007-05-18 ver 2.6.4" (( May work with kernel-2.6.4 ? ))

! And : kbleds.c is particularly buggy.

No luck with any kernel examples : 3.2.18 (gcc-4.5.2), 2.6.18 (gcc-4.1.2),
2.6.32 (gcc-4.4.6) at kbleds.c build.

-

bsat · 02-13-2013, 12:39 AM

here is the modified code for kernel version 3.7.5

http://tuxthink.blogspot.in/2013/02/...rsion-375.html

knudfl · 02-13-2013, 04:50 AM

# 5 : Thank you.

Looks like the new kbleds.c works OK for all kernel 3.x.x.
( A test was run with version 3.2.18 ).