kproc

diff --git a/kproc/Makefile b/kproc/Makefile
new file mode 100644 (file)
index 0000000..96b2aa4
--- /dev/null
+++ b/kproc/Makefile
@@ -0,0 +1,6 @@
+obj-m := kproc.o
+
+all:
+       make -C /lib/modules/$(shell uname -r)/build M=$(shell pwd) modules
+clean:
+       make -C /lib/modules/$(shell uname -r)/build M=$(shell pwd) clean
\ No newline at end of file

diff --git a/kproc/kproc.c b/kproc/kproc.c
new file mode 100644 (file)
index 0000000..701ed8e
--- /dev/null
+++ b/kproc/kproc.c
@@ -0,0 +1,111 @@
+#include <linux/init.h> 
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/types.h> 
+#include <linux/errno.h>  
+#include <linux/sched.h>
+#include <linux/sched/signal.h>
+
+#include <linux/fs.h>
+#include <linux/uaccess.h> 
+
+#include <linux/delay.h>
+#include <linux/workqueue.h>
+
+#include "kproc.h"
+
+#define DEVICE_NAME "kproc_f"
+
+static struct work_struct job;
+
+static int dev_major;
+static int device_open_counter = 0;
+static int work_done = 0;
+
+static void show_proc_context(char* buf){
+    unsigned int uid;
+    if(likely(in_task())){
+        uid = from_kuid(&init_user_ns, current_uid());
+        snprintf(buf, KPROC_BUFF_LEN, "kproc: ctx: process: uid: %u: pid: %d\n", uid, task_pid_nr(current));
+    } else {
+        snprintf(buf, KPROC_BUFF_LEN, "kproc: ctx: interrupt\n");
+    }
+}
+
+
+static int device_open(struct inode *inode, struct file *filp){
+  if (device_open_counter){
+    printk(KERN_INFO "not possible to open: already occupied: %d\n", device_open_counter);
+    return -EBUSY;
+  }
+  device_open_counter++;
+  printk(KERN_INFO "file opened: %d\n", device_open_counter);
+  try_module_get(THIS_MODULE);
+  return 0;
+}
+
+
+static int device_release(struct inode *inode, struct file *filp){
+  device_open_counter--;
+  printk(KERN_INFO "file closed: %d\n", device_open_counter);
+  module_put(THIS_MODULE);
+  return 0;
+}
+static ssize_t device_read(struct file *filp, char *buffer, size_t len, loff_t *offset){
+    char tmp_msg_buffer[KPROC_BUFF_LEN] = {0};
+    show_proc_context(tmp_msg_buffer);
+    ssize_t n = copy_to_user(buffer, tmp_msg_buffer, len);
+    (*offset) += len;
+    return KPROC_BUFF_LEN - n;
+}
+
+static ssize_t device_write(struct file *filp, const char *buf, size_t len, loff_t *offset){
+    printk(KERN_ALERT "kproc: write not allowed\n");
+    return -EINVAL;
+}
+
+static void job_handler(struct work_struct* work){
+    printk("kproc: job scheduled\n");
+    char tmp_msg_buffer[KPROC_BUFF_LEN] = {0};
+    while(!work_done){
+        show_proc_context(tmp_msg_buffer);
+        printk("kproc: job: %s\n", tmp_msg_buffer);
+        memset(tmp_msg_buffer, 0, KPROC_BUFF_LEN);
+        msleep(3000);
+    }
+    printk("kproc: job done\n");
+}
+
+static struct file_operations fops = {
+  .read = device_read,
+  .write = device_write,
+  .open = device_open,
+  .release = device_release
+};
+
+static int __init kproc_init(void){
+    dev_major = register_chrdev(0, DEVICE_NAME, &fops);
+    if (dev_major < 0) {
+        printk(KERN_ALERT "registering char device failed with %d\n", dev_major);
+        return dev_major;
+    }
+    INIT_WORK(&job, job_handler);
+    schedule_work(&job);
+    printk("kproc: hello\n");
+    return 0;
+}
+
+static void __exit kproc_exit(void){
+    work_done = 1;
+    printk("kproc: exit: waiting 5 seconds\n");
+    msleep(5000);
+    unregister_chrdev(dev_major, DEVICE_NAME);
+    printk("kproc: bye\n");
+}
+
+module_init(kproc_init);
+module_exit(kproc_exit);
+
+MODULE_LICENSE("GPL");
\ No newline at end of file

diff --git a/kproc/kproc.h b/kproc/kproc.h
new file mode 100644 (file)
index 0000000..0c7da2b
--- /dev/null
+++ b/kproc/kproc.h
@@ -0,0 +1,6 @@
+#ifndef _KPROC_H_
+#define _KPROC_H_
+
+#define KPROC_BUFF_LEN 128
+
+#endif
\ No newline at end of file

diff --git a/kproc/user/Makefile b/kproc/user/Makefile
new file mode 100644 (file)
index 0000000..421d819
--- /dev/null
+++ b/kproc/user/Makefile
@@ -0,0 +1,2 @@
+all:
+       gcc -g -o user.out user.c -lpthread
\ No newline at end of file

diff --git a/kproc/user/user.c b/kproc/user/user.c
new file mode 100644 (file)
index 0000000..f930ff3
--- /dev/null
+++ b/kproc/user/user.c
@@ -0,0 +1,4 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pthread.h>
\ No newline at end of file