kern_dtrace.c revision 211613 
1251777Sgrehan/*-
2251777Sgrehan * Copyright (c) 2007-2008 John Birrell <jb@FreeBSD.org>
3251777Sgrehan * All rights reserved.
4251777Sgrehan *
5251777Sgrehan * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/kern/kern_dtrace.c 211613 2010-08-22 11:08:18Z rpaulo $");
29
30#include "opt_kdb.h"
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/eventhandler.h>
35#include <sys/kdb.h>
36#include <sys/kernel.h>
37#include <sys/malloc.h>
38#include <sys/proc.h>
39#include <sys/dtrace_bsd.h>
40
41#define KDTRACE_PROC_SIZE	64
42#define KDTRACE_PROC_ZERO	8
43#define	KDTRACE_THREAD_SIZE	256
44#define	KDTRACE_THREAD_ZERO	64
45
46MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks");
47
48/* Return the DTrace process data size compiled in the kernel hooks. */
49size_t
50kdtrace_proc_size()
51{
52
53	return (KDTRACE_PROC_SIZE);
54}
55
56static void
57kdtrace_proc_ctor(void *arg __unused, struct proc *p)
58{
59	p->p_dtrace = malloc(KDTRACE_PROC_SIZE, M_KDTRACE, M_WAITOK);
60
61	bzero(p->p_dtrace, KDTRACE_PROC_ZERO);
62}
63
64static void
65kdtrace_proc_dtor(void *arg __unused, struct proc *p)
66{
67
68	if (p->p_dtrace != NULL) {
69		free(p->p_dtrace, M_KDTRACE);
70		p->p_dtrace = NULL;
71	}
72}
73
74/* Return the DTrace thread data size compiled in the kernel hooks. */
75size_t
76kdtrace_thread_size()
77{
78	return (KDTRACE_THREAD_SIZE);
79}
80
81static void
82kdtrace_thread_ctor(void *arg __unused, struct thread *td)
83{
84	td->td_dtrace = malloc(KDTRACE_THREAD_SIZE, M_KDTRACE, M_WAITOK);
85
86	bzero(td->td_dtrace, KDTRACE_THREAD_ZERO);
87}
88
89static void
90kdtrace_thread_dtor(void *arg __unused, struct thread *td)
91{
92
93	if (td->td_dtrace != NULL) {
94		free(td->td_dtrace, M_KDTRACE);
95		td->td_dtrace = NULL;
96	}
97}
98
99/*
100 *  Initialise the kernel DTrace hooks.
101 */
102static void
103init_dtrace(void *dummy __unused)
104{
105
106	EVENTHANDLER_REGISTER(process_ctor, kdtrace_proc_ctor, NULL,
107	    EVENTHANDLER_PRI_ANY);
108	EVENTHANDLER_REGISTER(process_dtor, kdtrace_proc_dtor, NULL,
109	    EVENTHANDLER_PRI_ANY);
110	EVENTHANDLER_REGISTER(thread_ctor, kdtrace_thread_ctor, NULL,
111	    EVENTHANDLER_PRI_ANY);
112	EVENTHANDLER_REGISTER(thread_dtor, kdtrace_thread_dtor, NULL,
113	    EVENTHANDLER_PRI_ANY);
114}
115
116SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL);
117