samples/tracepoints/tracepoint-sample.c

   1 /* tracepoint-sample.c
   2  *
   3  * Executes a tracepoint when /proc/tracepoint-sample 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/sched.h>
  13 #include <linux/proc_fs.h>
  14 #include "tp-samples-trace.h"
  15
  16 DEFINE_TRACE(subsys_event);
  17 DEFINE_TRACE(subsys_eventb);
  18
  19 struct proc_dir_entry *pentry_sample;
  20
  21 static int my_open(struct inode *inode, struct file *file)
  22 {
  23         int i;
  24
  25         trace_subsys_event(inode, file);
  26         for (i = 0; i < 10; i++)
  27                 trace_subsys_eventb();
  28         return -EPERM;
  29 }
  30
  31 static const struct file_operations mark_ops = {
  32         .open = my_open,
  33         .llseek = noop_llseek,
  34 };
  35
  36 static int __init sample_init(void)
  37 {
  38         printk(KERN_ALERT "sample init\n");
  39         pentry_sample = proc_create("tracepoint-sample", 0444, NULL,
  40                 &mark_ops);
  41         if (!pentry_sample)
  42                 return -EPERM;
  43         return 0;
  44 }
  45
  46 static void __exit sample_exit(void)
  47 {
  48         printk(KERN_ALERT "sample exit\n");
  49         remove_proc_entry("tracepoint-sample", NULL);
  50 }
  51
  52 module_init(sample_init)
  53 module_exit(sample_exit)
  54
  55 MODULE_LICENSE("GPL");
  56 MODULE_AUTHOR("Mathieu Desnoyers");
  57 MODULE_DESCRIPTION("Tracepoint sample");