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/* probe-example.c
*
* Connects two functions to marker call sites.
*
* (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
*
* This file is released under the GPLv2.
* See the file COPYING for more details.
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/marker.h>
#include <asm/atomic.h>
struct probe_data {
const char *name;
const char *format;
marker_probe_func *probe_func;
};
void probe_subsystem_event(void *probe_data, void *call_data,
const char *format, va_list *args)
{
/* Declare args */
unsigned int value;
const char *mystr;
/* Assign args */
value = va_arg(*args, typeof(value));
mystr = va_arg(*args, typeof(mystr));
/* Call printk */
printk(KERN_INFO "Value %u, string %s\n", value, mystr);
/* or count, check rights, serialize data in a buffer */
}
atomic_t eventb_count = ATOMIC_INIT(0);
void probe_subsystem_eventb(void *probe_data, void *call_data,
const char *format, va_list *args)
{
/* Increment counter */
atomic_inc(&eventb_count);
}
static struct probe_data probe_array[] =
{
{ .name = "subsystem_event",
.format = "integer %d string %s",
.probe_func = probe_subsystem_event },
{ .name = "subsystem_eventb",
.format = MARK_NOARGS,
.probe_func = probe_subsystem_eventb },
};
static int __init probe_init(void)
{
int result;
int i;
for (i = 0; i < ARRAY_SIZE(probe_array); i++) {
result = marker_probe_register(probe_array[i].name,
probe_array[i].format,
probe_array[i].probe_func, &probe_array[i]);
if (result)
printk(KERN_INFO "Unable to register probe %s\n",
probe_array[i].name);
}
return 0;
}
static void __exit probe_fini(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(probe_array); i++)
marker_probe_unregister(probe_array[i].name,
probe_array[i].probe_func, &probe_array[i]);
printk(KERN_INFO "Number of event b : %u\n",
atomic_read(&eventb_count));
}
module_init(probe_init);
module_exit(probe_fini);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("SUBSYSTEM Probe");
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