FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_dtrace.c

     /*-
      * Copyright (c) 2007-2008 John Birrell <jb@FreeBSD.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/10.0/sys/kern/kern_dtrace.c 227293 2011-11-07 06:44:47Z ed $");
    
    #include "opt_kdb.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/eventhandler.h>
    #include <sys/kdb.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/proc.h>
    #include <sys/dtrace_bsd.h>
    #include <sys/sysctl.h>
    
    #define KDTRACE_PROC_SIZE       64
    #define KDTRACE_THREAD_SIZE     256
    
    FEATURE(kdtrace_hooks,
        "Kernel DTrace hooks which are required to load DTrace kernel modules");
    
    static MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks");
    
    /* Return the DTrace process data size compiled in the kernel hooks. */
    size_t
    kdtrace_proc_size()
    {
    
            return (KDTRACE_PROC_SIZE);
    }
    
    static void
    kdtrace_proc_ctor(void *arg __unused, struct proc *p)
    {
    
            p->p_dtrace = malloc(KDTRACE_PROC_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
    }
    
    static void
    kdtrace_proc_dtor(void *arg __unused, struct proc *p)
    {
    
            if (p->p_dtrace != NULL) {
                    free(p->p_dtrace, M_KDTRACE);
                    p->p_dtrace = NULL;
            }
    }
    
    /* Return the DTrace thread data size compiled in the kernel hooks. */
    size_t
    kdtrace_thread_size()
    {
    
            return (KDTRACE_THREAD_SIZE);
    }
    
    static void
    kdtrace_thread_ctor(void *arg __unused, struct thread *td)
    {
    
            td->td_dtrace = malloc(KDTRACE_THREAD_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
    }
    
    static void
    kdtrace_thread_dtor(void *arg __unused, struct thread *td)
    {
    
            if (td->td_dtrace != NULL) {
                    free(td->td_dtrace, M_KDTRACE);
                    td->td_dtrace = NULL;
            }
    }
    
   /*
    *  Initialise the kernel DTrace hooks.
    */
   static void
   init_dtrace(void *dummy __unused)
   {
   
           EVENTHANDLER_REGISTER(process_ctor, kdtrace_proc_ctor, NULL,
               EVENTHANDLER_PRI_ANY);
           EVENTHANDLER_REGISTER(process_dtor, kdtrace_proc_dtor, NULL,
               EVENTHANDLER_PRI_ANY);
           EVENTHANDLER_REGISTER(thread_ctor, kdtrace_thread_ctor, NULL,
               EVENTHANDLER_PRI_ANY);
           EVENTHANDLER_REGISTER(thread_dtor, kdtrace_thread_dtor, NULL,
               EVENTHANDLER_PRI_ANY);
   }
   
   SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL);

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