sys/kern/kern_dtrace.c

   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("$FreeBSD$");
  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
  46 MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks");
  47
  48 /* Return the DTrace process data size compiled in the kernel hooks. */
  49 size_t
  50 kdtrace_proc_size()
  51 {
  52         return(KDTRACE_PROC_SIZE);
  53 }
  54
  55 static void
  56 kdtrace_proc_ctor(void *arg __unused, struct proc *p)
  57 {
  58         p->p_dtrace = malloc(KDTRACE_PROC_SIZE, M_KDTRACE, M_WAITOK);
  59
  60         bzero(p->p_dtrace, KDTRACE_PROC_ZERO);
  61 }
  62
  63 static void
  64 kdtrace_proc_dtor(void *arg __unused, struct proc *p)
  65 {
  66         if (p->p_dtrace != NULL) {
  67                 free(p->p_dtrace, M_KDTRACE);
  68                 p->p_dtrace = NULL;
  69         }
  70 }
  71
  72 /* Return the DTrace thread data size compiled in the kernel hooks. */
  73 size_t
  74 kdtrace_thread_size()
  75 {
  76         return(KDTRACE_THREAD_SIZE);
  77 }
  78
  79 static void
  80 kdtrace_thread_ctor(void *arg __unused, struct thread *td)
  81 {
  82         td->td_dtrace = malloc(KDTRACE_THREAD_SIZE, M_KDTRACE, M_WAITOK);
  83
  84         bzero(td->td_dtrace, KDTRACE_THREAD_ZERO);
  85 }
  86
  87 static void
  88 kdtrace_thread_dtor(void *arg __unused, struct thread *td)
  89 {
  90         if (td->td_dtrace != NULL) {
  91                 free(td->td_dtrace, M_KDTRACE);
  92                 td->td_dtrace = NULL;
  93         }
  94 }
  95
  96 /*
  97  *  Initialise the kernel DTrace hooks.
  98  */
  99 static void
 100 init_dtrace(void *dummy __unused)
 101 {
 102         EVENTHANDLER_REGISTER(process_ctor, kdtrace_proc_ctor, NULL, EVENTHANDLER_PRI_ANY);
 103         EVENTHANDLER_REGISTER(process_dtor, kdtrace_proc_dtor, NULL, EVENTHANDLER_PRI_ANY);
 104         EVENTHANDLER_REGISTER(thread_ctor, kdtrace_thread_ctor, NULL, EVENTHANDLER_PRI_ANY);
 105         EVENTHANDLER_REGISTER(thread_dtor, kdtrace_thread_dtor, NULL, EVENTHANDLER_PRI_ANY);
 106 }
 107
 108 SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL);