Makefile pour le module du noyau Linux?
Je viens de lire Le Module du Noyau Linux-Guide de Programmation et de et est resté coincé sur caractère pilotes de périphériques exemple.
Makefiles pour les exemples précédents ont été fournis, mais pas pour celui-ci, donc je vais essayer de faire un:
obj-m += chardev.o
all:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
clean:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
La sortie que j'obtiens est:
maciej@jadwiga:~/Projects/os/chardev$ make
make -C /lib/modules/2.6.26-2-686/build M=/home/maciej/Projects/os/chardev modules
make[1]: Entering directory `/usr/src/linux-headers-2.6.26-2-686'
CC [M] /home/maciej/Projects/os/chardev/chardev.o
/home/maciej/Projects/os/chardev/chardev.c: In function ‘cleanup_module’:
/home/maciej/Projects/os/chardev/chardev.c:72: error: void value not ignored as it ought to be
make[2]: *** [/home/maciej/Projects/os/chardev/chardev.o] Error 1
make[1]: *** [_module_/home/maciej/Projects/os/chardev] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-2.6.26-2-686'
make: *** [all] Error 2
Quelqu'un peut-il aider?
Le fichier que je veux compiler:
/*
* chardev.c: Creates a read-only char device that says how many times
* you've read from the dev file
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <asm/uaccess.h> /* for put_user */
/*
* Prototypes - this would normally go in a .h file
*/
int init_module(void);
void cleanup_module(void);
static int device_open(struct inode *, struct file *);
static int device_release(struct inode *, struct file *);
static ssize_t device_read(struct file *, char *, size_t, loff_t *);
static ssize_t device_write(struct file *, const char *, size_t, loff_t *);
#define SUCCESS 0
#define DEVICE_NAME "chardev" /* Dev name as it appears in /proc/devices */
#define BUF_LEN 80 /* Max length of the message from the device */
/*
* Global variables are declared as static, so are global within the file.
*/
static int Major; /* Major number assigned to our device driver */
static int Device_Open = 0; /* Is device open?
* Used to prevent multiple access to device */
static char msg[BUF_LEN]; /* The msg the device will give when asked */
static char *msg_Ptr;
static struct file_operations fops = {
.read = device_read,
.write = device_write,
.open = device_open,
.release = device_release
};
/*
* This function is called when the module is loaded
*/
int init_module(void)
{
Major = register_chrdev(0, DEVICE_NAME, &fops);
if (Major < 0) {
printk(KERN_ALERT "Registering char device failed with %d\n", Major);
return Major;
}
printk(KERN_INFO "I was assigned major number %d. To talk to\n", Major);
printk(KERN_INFO "the driver, create a dev file with\n");
printk(KERN_INFO "'mknod /dev/%s c %d 0'.\n", DEVICE_NAME, Major);
printk(KERN_INFO "Try various minor numbers. Try to cat and echo to\n");
printk(KERN_INFO "the device file.\n");
printk(KERN_INFO "Remove the device file and module when done.\n");
return SUCCESS;
}
/*
* This function is called when the module is unloaded
*/
void cleanup_module(void)
{
/*
* Unregister the device
*/
int ret = unregister_chrdev(Major, DEVICE_NAME);
if (ret < 0)
printk(KERN_ALERT "Error in unregister_chrdev: %d\n", ret);
}
/*
* Methods
*/
/*
* Called when a process tries to open the device file, like
* "cat /dev/mycharfile"
*/
static int device_open(struct inode *inode, struct file *file)
{
static int counter = 0;
if (Device_Open)
return -EBUSY;
Device_Open++;
sprintf(msg, "I already told you %d times Hello world!\n", counter++);
msg_Ptr = msg;
try_module_get(THIS_MODULE);
return SUCCESS;
}
/*
* Called when a process closes the device file.
*/
static int device_release(struct inode *inode, struct file *file)
{
Device_Open--; /* We're now ready for our next caller */
/*
* Decrement the usage count, or else once you opened the file, you'll
* never get get rid of the module.
*/
module_put(THIS_MODULE);
return 0;
}
/*
* Called when a process, which already opened the dev file, attempts to
* read from it.
*/
static ssize_t device_read(struct file *filp, /* see include/linux/fs.h */
char *buffer, /* buffer to fill with data */
size_t length, /* length of the buffer */
loff_t * offset)
{
/*
* Number of bytes actually written to the buffer
*/
int bytes_read = 0;
/*
* If we're at the end of the message,
* return 0 signifying end of file
*/
if (*msg_Ptr == 0)
return 0;
/*
* Actually put the data into the buffer
*/
while (length && *msg_Ptr) {
/*
* The buffer is in the user data segment, not the kernel
* segment so "*" assignment won't work. We have to use
* put_user which copies data from the kernel data segment to
* the user data segment.
*/
put_user(*(msg_Ptr++), buffer++);
length--;
bytes_read++;
}
/*
* Most read functions return the number of bytes put into the buffer
*/
return bytes_read;
}
/*
* Called when a process writes to dev file: echo "hi" > /dev/hello
*/
static ssize_t
device_write(struct file *filp, const char *buff, size_t len, loff_t * off)
{
printk(KERN_ALERT "Sorry, this operation isn't supported.\n");
return -EINVAL;
}
OriginalL'auteur matcheek | 2010-11-09
Vous devez vous connecter pour publier un commentaire.
Alors vous êtes en saisissant la valeur de retour d'une fonction qui n'en ont pas.
omg, c'est un exemple de l'officiel LKM tutoriel, aucune des lignes ont été changé par moi.
Ressemble à la fonction changé en 2007. Supprimer l'affectation de
ret
et les 2 lignes après.Vous avez besoin de l'appel à
unregister_chrdev()
. Suppression de l'attribution.OriginalL'auteur Ignacio Vazquez-Abrams
en fait le pilote est chargé par la macro MODULE_INIT(my_init);
ici "my_init" peut être spécifiée par l'utilisateur de la fonction et de
MUDULE_EXIT(my_cleanup);
ici my_exit peut être spécifiée par l'utilisateur de la fonction . ces deux macros sont manquants dans le code ci-dessus.
Makefile:
le obj-m += chardev.o doit être remplacé par obj-m := chardev.o.
Je suis aussi un débutant de LLD. Si une erreur est il s'il vous plaît laissez-moi savoir.
OriginalL'auteur ranganath
Parce que la fonction unregister_chrdev() ne retourne pas de valeur. C'est un lien utile. http://forum.kernelnewbies.org/read.php?17,1114
OriginalL'auteur Lam Hai Son