1 /*-
2 * Copyright (c) 2007-2008 John Birrell <jb@FreeBSD.org>
3 * All rights reserved.
4 *
5 * 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: releng/9.2/sys/kern/kern_dtrace.c 249132 2013-04-05 08:22:11Z mav $");
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 #include <sys/sysctl.h>
41
42 #define KDTRACE_PROC_SIZE 64
43 #define KDTRACE_THREAD_SIZE 256
44
45 FEATURE(kdtrace_hooks,
46 "Kernel DTrace hooks which are required to load DTrace kernel modules");
47
48 static MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks");
49
50 /* Return the DTrace process data size compiled in the kernel hooks. */
51 size_t
52 kdtrace_proc_size()
53 {
54
55 return (KDTRACE_PROC_SIZE);
56 }
57
58 static void
59 kdtrace_proc_ctor(void *arg __unused, struct proc *p)
60 {
61
62 p->p_dtrace = malloc(KDTRACE_PROC_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
63 }
64
65 static void
66 kdtrace_proc_dtor(void *arg __unused, struct proc *p)
67 {
68
69 if (p->p_dtrace != NULL) {
70 free(p->p_dtrace, M_KDTRACE);
71 p->p_dtrace = NULL;
72 }
73 }
74
75 /* Return the DTrace thread data size compiled in the kernel hooks. */
76 size_t
77 kdtrace_thread_size()
78 {
79
80 return (KDTRACE_THREAD_SIZE);
81 }
82
83 static void
84 kdtrace_thread_ctor(void *arg __unused, struct thread *td)
85 {
86
87 td->td_dtrace = malloc(KDTRACE_THREAD_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
88 }
89
90 static void
91 kdtrace_thread_dtor(void *arg __unused, struct thread *td)
92 {
93
94 if (td->td_dtrace != NULL) {
95 free(td->td_dtrace, M_KDTRACE);
96 td->td_dtrace = NULL;
97 }
98 }
99
100 /*
101 * Initialise the kernel DTrace hooks.
102 */
103 static void
104 init_dtrace(void *dummy __unused)
105 {
106
107 EVENTHANDLER_REGISTER(process_ctor, kdtrace_proc_ctor, NULL,
108 EVENTHANDLER_PRI_ANY);
109 EVENTHANDLER_REGISTER(process_dtor, kdtrace_proc_dtor, NULL,
110 EVENTHANDLER_PRI_ANY);
111 EVENTHANDLER_REGISTER(thread_ctor, kdtrace_thread_ctor, NULL,
112 EVENTHANDLER_PRI_ANY);
113 EVENTHANDLER_REGISTER(thread_dtor, kdtrace_thread_dtor, NULL,
114 EVENTHANDLER_PRI_ANY);
115 }
116
117 SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL);
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