kernel hello world

Author: d-grossman

linux_kernel/Makefile

@@ -0,0 +1,7 @@
+obj-m += hello_world_d-grossman.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

linux_kernel/hello_world_d-grossman.c

@@ -0,0 +1,84 @@
+/*
+language: c
+env: 
+author: d-grossman
+github:
+
+
+*/
+
+
+/*
+make
+insmod hello_world_d-grossman
+ls /proc/hello_world
+cat /proc/hello_world
+rmmod hello_world_d-grossman
+
+*/
+
+
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#define procfs_msg "Hello World\n"
+#define procfs_name "hello_world"
+#define procfs_parent NULL
+#define procfs_perms 0644
+
+static struct proc_dir_entry *hello_world_file;
+
+static int
+hello_world_show (struct seq_file *m, void *v)
+{
+  seq_printf (m, "%s\n", procfs_msg);
+
+  return 0;
+}
+
+static int
+hello_world_open (struct inode *inode, struct file *file)
+{
+  return single_open (file, hello_world_show, NULL);
+}
+
+static const struct file_operations hello_world_fops = {
+  .owner = THIS_MODULE,
+  .open = hello_world_open,
+  .read = seq_read,
+  .llseek = seq_lseek,
+  .release = single_release,
+};
+
+static int __init
+hello_world_init (void)
+{
+  hello_world_file =
+    proc_create (procfs_name, procfs_perms, procfs_parent, &hello_world_fops);
+
+  if (!hello_world_file)
+    {
+      return -ENOMEM;
+    }
+
+  return 0;
+}
+
+static void __exit
+hello_world_exit (void)
+{
+  remove_proc_entry ("hello_world", procfs_parent);
+}
+
+module_init (hello_world_init);
+module_exit (hello_world_exit);
+
+MODULE_LICENSE ("GPL");
+MODULE_AUTHOR ("d-grossman");
+MODULE_DESCRIPTION ("procfs hello world");