68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
|
/*
|
||
|
|
* Here's a sample kernel module showing the use of jprobes to dump
|
||
|
|
* the arguments of _do_fork().
|
||
|
|
*
|
||
|
|
* For more information on theory of operation of jprobes, see
|
||
|
|
* Documentation/kprobes.txt
|
||
|
|
*
|
||
|
|
* Build and insert the kernel module as done in the kprobe example.
|
||
|
|
* You will see the trace data in /var/log/messages and on the
|
||
|
|
* console whenever _do_fork() is invoked to create a new process.
|
||
|
|
* (Some messages may be suppressed if syslogd is configured to
|
||
|
|
* eliminate duplicate messages.)
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/module.h>
|
||
|
|
#include <linux/kprobes.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Jumper probe for _do_fork.
|
||
|
|
* Mirror principle enables access to arguments of the probed routine
|
||
|
|
* from the probe handler.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* Proxy routine having the same arguments as actual _do_fork() routine */
|
||
|
|
static long j_do_fork(unsigned long clone_flags, unsigned long stack_start,
|
||
|
|
unsigned long stack_size, int __user *parent_tidptr,
|
||
|
|
int __user *child_tidptr, unsigned long tls)
|
||
|
|
{
|
||
|
|
pr_info("jprobe: clone_flags = 0x%lx, stack_start = 0x%lx "
|
||
|
|
"stack_size = 0x%lx\n", clone_flags, stack_start, stack_size);
|
||
|
|
|
||
|
|
/* Always end with a call to jprobe_return(). */
|
||
|
|
jprobe_return();
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct jprobe my_jprobe = {
|
||
|
|
.entry = j_do_fork,
|
||
|
|
.kp = {
|
||
|
|
.symbol_name = "_do_fork",
|
||
|
|
},
|
||
|
|
};
|
||
|
|
|
||
|
|
static int __init jprobe_init(void)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
ret = register_jprobe(&my_jprobe);
|
||
|
|
if (ret < 0) {
|
||
|
|
pr_err("register_jprobe failed, returned %d\n", ret);
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
pr_info("Planted jprobe at %p, handler addr %p\n",
|
||
|
|
my_jprobe.kp.addr, my_jprobe.entry);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __exit jprobe_exit(void)
|
||
|
|
{
|
||
|
|
unregister_jprobe(&my_jprobe);
|
||
|
|
pr_info("jprobe at %p unregistered\n", my_jprobe.kp.addr);
|
||
|
|
}
|
||
|
|
|
||
|
|
module_init(jprobe_init)
|
||
|
|
module_exit(jprobe_exit)
|
||
|
|
MODULE_LICENSE("GPL");
|