/* * 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 jdo_fork(unsigned long clone_flags, unsigned long stack_start, struct pt_regs *regs, unsigned long stack_size, int __user *parent_tidptr, int __user *child_tidptr) { printk(KERN_INFO "jprobe: clone_flags = 0x%lx, stack_size = 0x%lx," " regs = 0x%p\n", clone_flags, stack_size, regs); /* Always end with a call to jprobe_return(). */ jprobe_return(); return 0; } static struct jprobe my_jprobe = { .entry = jdo_fork, .kp = { .symbol_name = "do_fork", }, }; static int __init jprobe_init(void) { int ret; ret = register_jprobe(&my_jprobe); if (ret < 0) { printk(KERN_INFO "register_jprobe failed, returned %d\n", ret); return -1; } printk(KERN_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); printk(KERN_INFO "jprobe at %p unregistered\n", my_jprobe.kp.addr); } module_init(jprobe_init) module_exit(jprobe_exit) MODULE_LICENSE("GPL");