kerne module

[tintu1212]

hi all,
i want to know how can i add or remove kernel module in application and also send me how to program.........pls help me........

[vedasolutions]

If i understand correctly, you want to know how to write an application which inserts and removes a module. I mean instead of using insmod and rmmod tools, you want to do that in the application. If my understanding is correct, you can try the following program.

#include <sys/mman.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <limits.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <string.h>


#define init_module(mod, len, opts) syscall(__NR_init_module, mod, len, opts)
#define delete_module(mod, flags) syscall(__NR_delete_module, mod, flags)

void* try_to_mmap_module(const char *filename, size_t *image_size_p)
{
void *image;
struct stat st;
int fd;

fd = open(filename, O_RDONLY);
if (fd < 0)
return NULL;

fstat(fd, &st);
image = NULL;
/* st.st_size is off_t, we can't just pass it to mmap */
if (st.st_size <= *image_size_p) {
size_t image_size = st.st_size;
image = mmap(NULL, image_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (image == MAP_FAILED) {
image = NULL;
} else {
/* Success. Report the size */
*image_size_p = image_size;
}
}
close(fd);
return image;
}


int main(void)
{
char *module = "module.ko";
size_t image_size;
char *image;
int rc;
char *options = "";
char mod[100]; // max module name

image_size = INT_MAX - 4095;
image = try_to_mmap_module(module, &image_size);
if (!image) {
printf("\nCannot mmap the module\n");
return 0;
}

rc = init_module(image, image_size, options);
if (rc < 0) {
perror("init_module");
}

munmap(image, image_size);

/*
* To remove the module, uncomment the following code
*/
// strncpy(mod, module, strlen(module) - 3);

// rc = delete_module(mod, 0);
// if (rc)
// perror("delete_module");
}

[tintu1212]

hi vedasolutions,
thank you for ur reply...i will check it ...........

[vedasolutions]

The programs mmaps the given module (module.ko). mmap will copy the module into the memory and returns its pointer. I am invoking a system call init_module using the syscall() function. For the system call I am giving the address of the module where it has been loaded and some other flags. delete_module is to invoke delete_module system call to remove the module. delete_module() takes the module name (without .ko) and removes the module.

[tintu1212]

thank u.............

[daark.child]

This article may help you with some of your questions.

[vedasolutions]

Use modprobe command. First copy your module into /lib/modules/$(shell uname -r)/kernel and type depmod command, like this:

$cp module.ko /lib/modules/$(shell uname -r)/kernel

$sudo depmod
$modprobe module (note no .ko here)

[tintu1212]

hi,

thank u...but how to know which modules are necessary & whichever unnecessary in that kernel....how to remove it?..& how to add some modules whenever we want?...how to know the modules interconnected with another one?...how it is automatically removed?..pls help me.......