trunk/tests/kernel/probe.c

   1 /* probe.c
   2  *
   3  * Loads a function at a marker call site.
   4  *
   5  * (C) Copyright 2006 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/marker.h>
  12 #include <linux/module.h>
  13 #include <linux/kallsyms.h>
  14
  15 /* function to install */
  16 #define DO_MARK1_FORMAT "%d"
  17 void do_mark1(const char *format, ...)
  18 {
  19         va_list ap;
  20         int value;
  21
  22         va_start(ap, format);
  23         value = va_arg(ap, int);
  24         printk("value is %d\n", value);
  25
  26         va_end(ap);
  27 }
  28
  29 void do_mark2(const char *format, ...)
  30 {
  31         va_list ap;
  32
  33         va_start(ap, format);
  34         vprintk(format, ap);
  35         va_end(ap);
  36         printk("\n");
  37 }
  38
  39 #define DO_MARK3_FORMAT "%d %s %s"
  40 void do_mark3(const char *format, ...)
  41 {
  42         va_list ap;
  43         int value;
  44         const char *s1, *s2;
  45
  46         va_start(ap, format);
  47         value = va_arg(ap, int);
  48         s1 = va_arg(ap, const char*);
  49         s2 = va_arg(ap, const char *);
  50
  51         printk("value is %d %s %s\n",
  52                 value, s1, s2);
  53         va_end(ap);
  54 }
  55
  56 int init_module(void)
  57 {
  58         int result;
  59         result = marker_set_probe("subsys_mark1", DO_MARK1_FORMAT,
  60                         (marker_probe_func*)do_mark1);
  61         if(!result) goto end;
  62         result = marker_set_probe("subsys_mark2", NULL,
  63                         (marker_probe_func*)do_mark2);
  64         if(!result) goto cleanup1;
  65         result = marker_set_probe("subsys_mark3", DO_MARK3_FORMAT,
  66                         (marker_probe_func*)do_mark3);
  67         if(!result) goto cleanup2;
  68
  69         return 0;
  70
  71 cleanup2:
  72         marker_remove_probe((marker_probe_func*)do_mark2);
  73 cleanup1:
  74         marker_remove_probe((marker_probe_func*)do_mark1);
  75 end:
  76         return -EPERM;
  77 }
  78
  79 void cleanup_module(void)
  80 {
  81         marker_remove_probe((marker_probe_func*)do_mark1);
  82         marker_remove_probe((marker_probe_func*)do_mark2);
  83         marker_remove_probe((marker_probe_func*)do_mark3);
  84 }
  85
  86 MODULE_LICENSE("GPL");
  87 MODULE_AUTHOR("Mathieu Desnoyers");
  88 MODULE_DESCRIPTION("Probe");