Procfs hello world

12 Oct 2011 Fuck you world... I will learn kernel, getting payed or not!!


Here is a simple procfs hello world


The source (proc2.c)

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>

static struct proc_dir_entry *proc_file;

int procfile_read(char *buf, char **buf_location, off_t offset,
 int buf_len, int *eof, void *data)
{
 return sprintf(buf, "Hello Word\n"); 
}

#define PROC_FILE_NAME "hello"
int init_module()
{
 proc_file = create_proc_entry(PROC_FILE_NAME, 0644, NULL);
 if (!proc_file) { 
  remove_proc_entry(PROC_FILE_NAME, NULL);
  return -ENOMEM;
 } 
 proc_file->read_proc = procfile_read;
 proc_file->mode = 0644;
 proc_file->uid = 0;
 proc_file->gid = 0;
 proc_file->size = 37;
 return 0;
}


void cleanup_module()
{
 remove_proc_entry(PROC_FILE_NAME, NULL);
}

The Makefile

obj-m += proc2.o

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

Compiling and running

Cheers :-P