samples/markers/marker-example.c

   1 /* marker-example.c
   2  *
   3  * Executes a marker when /proc/marker-example is opened.
   4  *
   5  * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
   6  *
   7  * This file is released under the GPLv2.
   8  * See the file COPYING for more details.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/marker.h>
  13 #include <linux/sched.h>
  14 #include <linux/proc_fs.h>
  15
  16 struct proc_dir_entry *pentry_example;
  17
  18 static int my_open(struct inode *inode, struct file *file)
  19 {
  20         int i;
  21
  22         trace_mark(subsystem_event, "%d %s", 123, "example string");
  23         for (i = 0; i < 10; i++)
  24                 trace_mark(subsystem_eventb, MARK_NOARGS);
  25         return -EPERM;
  26 }
  27
  28 static struct file_operations mark_ops = {
  29         .open = my_open,
  30 };
  31
  32 static int example_init(void)
  33 {
  34         printk(KERN_ALERT "example init\n");
  35         pentry_example = create_proc_entry("marker-example", 0444, NULL);
  36         if (pentry_example)
  37                 pentry_example->proc_fops = &mark_ops;
  38         else
  39                 return -EPERM;
  40         return 0;
  41 }
  42
  43 static void example_exit(void)
  44 {
  45         printk(KERN_ALERT "example exit\n");
  46         remove_proc_entry("marker-example", NULL);
  47 }
  48
  49 module_init(example_init)
  50 module_exit(example_exit)
  51
  52 MODULE_LICENSE("GPL");
  53 MODULE_AUTHOR("Mathieu Desnoyers");
  54 MODULE_DESCRIPTION("Marker example");