common/tnf/tnf.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


/*
 * tnf driver - provides probe control and kernel trace buffer access
 * to the user programs prex and tnfxtract.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/file.h>
#include <sys/cmn_err.h>
#include <sys/fcntl.h>
#include <sys/uio.h>
#include <sys/kmem.h>
#include <sys/cred.h>
#include <sys/mman.h>
#include <sys/errno.h>
#include <sys/stat.h>
#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/modctl.h>
#include <sys/tnf.h>
#include <sys/debug.h>
#include <sys/devops.h>
#include <vm/as.h>
#include <vm/seg_kp.h>
#include <sys/tnf_probe.h>
#include <sys/kobj.h>

#include "tnf_buf.h"
#include "tnf_types.h"
#include "tnf_trace.h"

#ifndef NPROBE

/*
 * Each probe is independently put in the kernel, prex uses
 * __tnf_probe_list_head and __tnf_tag_list_head as pointers to linked list
 * for probes and static tnf_tag_data_t, respectively.
 * tnf used the elf relocation record to build a separate linked list for
 * the probes and tnf_tag_data_t. We will describe how the linked list for
 * __tnf_tag_list_head is made, the probe list is very similar.
 * During the dynamic relocation(in uts/sparc/krtld/kobj_reloc.c),
 * the &__tnf_tag_version_1(the first member in tnf_tag_data_t data struct)
 * (and since it is a global variable which was never defined) will be filled
 * with 0. The following code in kobj_reloc.c will get the address of current
 * __tnf_tag_list_head and put it in value_p:
 *   #define TAG_MARKER_SYMBOL       "__tnf_tag_version_1"
 *   if (strcmp(symname, TAG_MARKER_SYMBOL) == 0) {
 *       *addend_p = 0;
 *       *value_p = (Addr) __tnf_tag_list_head; (value_p points to list head)
 *       __tnf_tag_list_head = (void *)*offset_p;(list head is the next record)
 *       return (0);
 *   }
 *
 * the function do_reloc(in the kobj_reloc.c) will put vlaue_p into
 * &__tnf_tag_version_1
 * Now the &__tnf_tag_version_1 points to the last list head
 * and __tnf_tag_list_head points to the new list head.
 * This is equivalent to attatch a node at the beginning of the list.
 *
 */
extern tnf_probe_control_t *__tnf_probe_list_head;
extern tnf_tag_data_t *__tnf_tag_list_head;
extern int tnf_changed_probe_list;

static int tnf_attach(dev_info_t *, ddi_attach_cmd_t);
static int tnf_detach(dev_info_t *, ddi_detach_cmd_t);
static int tnf_info(dev_info_t *, ddi_info_cmd_t, void *, void **);
static int tnf_open(dev_t *, int, int, struct cred *);
static int tnf_close(dev_t, int, int, struct cred *);
#ifdef UNUSED
static int tnf_mmap(dev_t, off_t, int);
#endif
static int tnf_ioctl(dev_t, int, intptr_t, int, struct cred *, int *);
#ifdef UNUSED
static int tnf_prop_op(dev_t, dev_info_t *, ddi_prop_op_t,
    int, char *, caddr_t, int *);
#endif
static dev_info_t *tnf_devi;

static struct {
    int     tnf_probe_count;
    boolean_t   tnf_pidfilter_mode;
    boolean_t   ctldev_is_open;
    int     mapdev_open_count;
    kmutex_t    tnf_mtx;
} tnf_drv_state = { 0, B_FALSE, B_FALSE, 0 };

static int tnf_getmaxprobe(caddr_t, int);
static int tnf_getprobevals(caddr_t, int);
static int tnf_getprobestring(caddr_t, int);
static int tnf_setprobevals(caddr_t, int);
static int tnf_getstate(caddr_t, int);
static int tnf_allocbuf(intptr_t);
static int tnf_deallocbuf(void);
static int tnf_settracing(int);
static int tnf_pidfilterset(int);
static int tnf_pidfilterget(caddr_t, int);
static int tnf_getpidstate(caddr_t, int);
static int tnf_setpidstate(int, pid_t, int);
static int tnf_getheader(caddr_t, int);
static int tnf_getblock(caddr_t, int);
static int tnf_getfwzone(caddr_t, int);

static void *tnf_test_1(void *, tnf_probe_control_t *, tnf_probe_setup_t *);
static void *tnf_test_2(void *, tnf_probe_control_t *, tnf_probe_setup_t *);

#define TNFCTL_MINOR 0
#define TNFMAP_MINOR 1

struct cb_ops   tnf_cb_ops = {
    tnf_open,       /* open */
    tnf_close,      /* close */
    nodev,          /* strategy */
    nodev,          /* print */
    nodev,          /* dump */
    nodev,          /* read */
    nodev,          /* write */
    tnf_ioctl,      /* ioctl */
    nodev,          /* devmap */
    nodev,          /* mmap */
    nodev,          /* segmap */
    nochpoll,       /* poll */
    ddi_prop_op,        /* prop_op */
    0,          /* streamtab  */
    D_NEW | D_MP        /* Driver compatibility flag */
};

struct dev_ops  tnf_ops = {
    DEVO_REV,       /* devo_rev, */
    0,          /* refcnt  */
    tnf_info,       /* info */
    nulldev,        /* identify */
    nulldev,        /* probe */
    tnf_attach,     /* attach */
    tnf_detach,     /* detach */
    nodev,          /* reset */
    &tnf_cb_ops,        /* driver operations */
    (struct bus_ops *)0,    /* no bus operations */
    NULL,           /* power */
    ddi_quiesce_not_needed,     /* quiesce */
};

extern struct mod_ops mod_driverops;

static struct modldrv modldrv = {
    &mod_driverops,
    "kernel probes driver",
    &tnf_ops,
};

static struct modlinkage modlinkage = {
    MODREV_1,
    (void *)&modldrv,
    NULL
};

int
_init()
{
    register int error;

    mutex_init(&tnf_drv_state.tnf_mtx, NULL, MUTEX_DEFAULT, NULL);

    if ((error = mod_install(&modlinkage)) != 0) {
        mutex_destroy(&tnf_drv_state.tnf_mtx);
        return (error);
    }

    /* Give t0 a tpdp */
    if (!t0.t_tnf_tpdp)
        t0.t_tnf_tpdp = kmem_zalloc(sizeof (tnf_ops_t), KM_SLEEP);
    /* Initialize tag system */
    tnf_tag_core_init();
    tnf_tag_trace_init();
    tnf_changed_probe_list = 1;
    return (0);
}

int
_fini()
{
    /* Not safe to unload this module, currently */
    return (EBUSY);
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&modlinkage, modinfop));
}

/* ARGSUSED */
static int
tnf_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
{
    register int error;

    switch (infocmd) {
    case DDI_INFO_DEVT2DEVINFO:
        *result = (void *)tnf_devi;
        error = DDI_SUCCESS;
        break;
    case DDI_INFO_DEVT2INSTANCE:
        *result = (void *)0;
        error = DDI_SUCCESS;
        break;
    default:
        error = DDI_FAILURE;
    }
    return (error);
}

static int
tnf_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
    if (cmd != DDI_ATTACH)
        return (DDI_FAILURE);
    if ((ddi_create_minor_node(devi, "tnfctl", S_IFCHR, TNFCTL_MINOR,
        DDI_PSEUDO, NULL) == DDI_FAILURE) ||
        (ddi_create_minor_node(devi, "tnfmap", S_IFCHR, TNFMAP_MINOR,
        DDI_PSEUDO, NULL) == DDI_FAILURE)) {
        ddi_remove_minor_node(devi, NULL);
        return (DDI_FAILURE);
    }
    tnf_devi = devi;
    return (DDI_SUCCESS);
}

static int
tnf_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
    if (cmd != DDI_DETACH)
        return (DDI_FAILURE);
    ddi_remove_minor_node(devi, NULL);
    return (DDI_SUCCESS);
}

/*
 * property operations. Return the size of the kernel trace buffer.  We
 * only handle size property requests.  Others are passed on.
 */
#ifdef UNUSED
static int
tnf_prop_op(dev_t dev, dev_info_t *di, ddi_prop_op_t prop,
    int m, char *name, caddr_t valuep, int *lengthp)
{
    int length, *retbuf, size;

    if (strcmp(name, "size") == 0) {

        /* Don't need tnf_mtx, since mapdev_open_count > 0 */
        size = tnf_trace_file_size;

        length = *lengthp;      /* get caller's length */
        *lengthp = sizeof (int);    /* set caller's length */

        switch (prop) {

        case PROP_LEN:
            return (DDI_PROP_SUCCESS);

        case PROP_LEN_AND_VAL_ALLOC:
            retbuf = kmem_alloc(sizeof (int),
                (m & DDI_PROP_CANSLEEP) ? KM_SLEEP : KM_NOSLEEP);
            if (retbuf == NULL)
                return (DDI_PROP_NO_MEMORY);
            *(int **)valuep = retbuf;   /* set caller's buf */
            *retbuf = size;
            return (DDI_PROP_SUCCESS);

        case PROP_LEN_AND_VAL_BUF:
            if (length < sizeof (int))
                return (DDI_PROP_BUF_TOO_SMALL);
            *(int *)valuep = size;
            return (DDI_PROP_SUCCESS);
        }
    }
    return (ddi_prop_op(dev, dip, prop, m, name, valuep, lengthp));
}
#endif

/* ARGSUSED */
static int
tnf_open(dev_t *devp, int flag, int otyp, struct cred *cred)
{
    int err = 0;
    mutex_enter(&tnf_drv_state.tnf_mtx);
    if (getminor(*devp) == TNFCTL_MINOR) {
        if (tnf_drv_state.ctldev_is_open)
            err = EBUSY;
        else {
            tnf_drv_state.ctldev_is_open = B_TRUE;
            /* stop autounloading -- XXX temporary */
            modunload_disable();
        }
    } else {
        /* ASSERT(getminor(*devp) == TNFMAP_MINOR) */
        ++tnf_drv_state.mapdev_open_count;
    }
    mutex_exit(&tnf_drv_state.tnf_mtx);
    return (err);
}

/* ARGSUSED */
static int
tnf_close(dev_t dev, int flag, int otyp, struct cred *cred)
{
    if (getminor(dev) == TNFCTL_MINOR) {
        /*
         * Request the reenablement of autounloading
         */
        modunload_enable();
        tnf_drv_state.ctldev_is_open = B_FALSE;
    } else {
        /* ASSERT(getminor(dev) == TNFMAP_MINOR) */
        /*
         * Unconditionally zero the open count since close()
         * is called when last client closes the device.
         */
        tnf_drv_state.mapdev_open_count = 0;
    }
    return (0);
}

/*
 * return the address of the image referenced by dev.
 *
 * 1191344: aliasing problem on VAC machines.  It could be made to
 * work by ensuring that tnf_buf is allocated on a vac_size boundary.
 */
#ifdef UNUSED
/*ARGSUSED*/
static int
tnf_mmap(dev_t dev, off_t off, int prot)
{
    register caddr_t addr;
    register caddr_t pg_offset;

    if (getminor(dev) != TNFMAP_MINOR)
        return (-1);
    if (tnf_buf == 0 || off >= tnf_trace_file_size) {
        return (-1);
    }

    addr = tnf_buf;
    pg_offset = (caddr_t)((ulong_t)addr + (ulong_t)off);
    return ((int)hat_getpfnum(kas.a_hat, pg_offset));
}
#endif

/*ARGSUSED4*/
static int
tnf_ioctl(dev_t dev, int cmd, intptr_t arg, int mode,
    cred_t *credp, int *rvalp)
{
    int filterval = 1;

    if ((mode & FMODELS) != FNATIVE)
        return (ENOTSUP);

    if (getminor(dev) != TNFCTL_MINOR &&
        cmd != TIFIOCGSTATE &&
        cmd != TIFIOCGHEADER &&
        cmd != TIFIOCGBLOCK &&
        cmd != TIFIOCGFWZONE)
        return (EINVAL);

    switch (cmd) {
    case TIFIOCGMAXPROBE:
        return (tnf_getmaxprobe((caddr_t)arg, mode));
    case TIFIOCGPROBEVALS:
        return (tnf_getprobevals((caddr_t)arg, mode));
    case TIFIOCGPROBESTRING:
        return (tnf_getprobestring((caddr_t)arg, mode));
    case TIFIOCSPROBEVALS:
        return (tnf_setprobevals((caddr_t)arg, mode));
    case TIFIOCGSTATE:
        return (tnf_getstate((caddr_t)arg, mode));
    case TIFIOCALLOCBUF:
        return (tnf_allocbuf(arg));
    case TIFIOCDEALLOCBUF:
        return (tnf_deallocbuf());
    case TIFIOCSTRACING:
        /* LINTED cast from 64-bit integer to 32-bit integer */
        return (tnf_settracing((int)arg));
    case TIFIOCSPIDFILTER:
        /* LINTED cast from 64-bit integer to 32-bit integer */
        return (tnf_pidfilterset((int)arg));
    case TIFIOCGPIDSTATE:
        return (tnf_getpidstate((caddr_t)arg, mode));
    case TIFIOCSPIDOFF:
        filterval = 0;
        /*FALLTHROUGH*/
    case TIFIOCSPIDON:
        /* LINTED cast from 64-bit integer to 32-bit integer */
        return (tnf_setpidstate(filterval, (pid_t)arg, mode));
    case TIFIOCPIDFILTERGET:
        return (tnf_pidfilterget((caddr_t)arg, mode));
    case TIFIOCGHEADER:
        return (tnf_getheader((caddr_t)arg, mode));
    case TIFIOCGBLOCK:
        return (tnf_getblock((caddr_t)arg, mode));
    case TIFIOCGFWZONE:
        return (tnf_getfwzone((caddr_t)arg, mode));
    default:
        return (EINVAL);
    }
}

/*
 * ioctls
 */

static int
tnf_getmaxprobe(caddr_t arg, int mode)
{
    tnf_probe_control_t *p;
    /*
     * XXX Still not right for module unload -- just counting
     * the probes is not enough
     */
    if (tnf_changed_probe_list) {
        mutex_enter(&mod_lock);
        tnf_changed_probe_list = 0;
        tnf_drv_state.tnf_probe_count = 0;
        for (p = (tnf_probe_control_t *)__tnf_probe_list_head;
            p != 0; p = p->next)
            ++tnf_drv_state.tnf_probe_count;
        mutex_exit(&mod_lock);
    }
    if (ddi_copyout((caddr_t)&tnf_drv_state.tnf_probe_count,
        arg, sizeof (tnf_drv_state.tnf_probe_count), mode))
        return (EFAULT);
    return (0);
}

static int
tnf_getprobevals(caddr_t arg, int mode)
{
    tnf_probevals_t probebuf;
    tnf_probe_control_t *p;
    int i, retval = 0;

    if (ddi_copyin(arg, (caddr_t)&probebuf, sizeof (probebuf), mode))
        return (EFAULT);

    mutex_enter(&mod_lock);
    for (i = 1, p = (tnf_probe_control_t *)__tnf_probe_list_head;
        p != NULL && i != probebuf.probenum;
        ++i, p = p->next)
        ;
    if (p == NULL)
        retval = ENOENT;
    else {
        probebuf.enabled = (p->test_func != NULL);
        probebuf.traced = (p->probe_func == tnf_trace_commit);
        /* LINTED assignment of 64-bit integer to 32-bit integer */
        probebuf.attrsize = strlen(p->attrs) + 1;
        if (ddi_copyout((caddr_t)&probebuf,
            arg, sizeof (probebuf), mode))
            retval = EFAULT;
    }
    mutex_exit(&mod_lock);
    return (retval);
}

static int
tnf_getprobestring(caddr_t arg, int mode)
{
    tnf_probevals_t probebuf;
    tnf_probe_control_t *p;
    int i, retval = 0;

    if (ddi_copyin(arg, (caddr_t)&probebuf, sizeof (probebuf), mode))
        return (EFAULT);

    mutex_enter(&mod_lock);
    for (i = 1, p = (tnf_probe_control_t *)__tnf_probe_list_head;
        p != NULL && i != probebuf.probenum;
        ++i, p = p->next)
        ;
    if (p == NULL)
        retval = ENOENT;
    else if (ddi_copyout((caddr_t)p->attrs,
        arg, strlen(p->attrs) + 1, mode))
        retval = EFAULT;
    mutex_exit(&mod_lock);
    return (retval);
}

static int
tnf_setprobevals(caddr_t arg, int mode)
{
    tnf_probevals_t probebuf;
    tnf_probe_control_t *p;
    int i, retval = 0;

    if (ddi_copyin(arg, (caddr_t)&probebuf, sizeof (probebuf), mode))
        return (EFAULT);

    mutex_enter(&mod_lock);
    for (i = 1, p = (tnf_probe_control_t *)__tnf_probe_list_head;
        p != NULL && i != probebuf.probenum;
        ++i, p = p->next)
        ;
    if (p == NULL)
        retval = ENOENT;
    else {
        /*
         * First do trace, then enable.
         * Set test_func last.
         */
        if (probebuf.traced)
            p->probe_func = tnf_trace_commit;
        else
            p->probe_func = tnf_trace_rollback;
        if (probebuf.enabled) {
            p->alloc_func = tnf_trace_alloc;
            /* this must be set last */
            if (tnf_drv_state.tnf_pidfilter_mode)
                p->test_func = tnf_test_2;
            else
                p->test_func = tnf_test_1;
        } else
            p->test_func = NULL;
    }
    mutex_exit(&mod_lock);
    return (retval);
}

static int
tnf_getstate(caddr_t arg, int mode)
{
    tifiocstate_t   tstate;
    proc_t      *procp;

    if (tnf_buf == NULL) {
        tstate.buffer_state = TIFIOCBUF_NONE;
        tstate.buffer_size = 0;
    } else {
        switch (tnfw_b_state & ~TNFW_B_STOPPED) {
        case TNFW_B_RUNNING:
            tstate.buffer_state = TIFIOCBUF_OK;
            break;
        case TNFW_B_NOBUFFER:
            tstate.buffer_state = TIFIOCBUF_UNINIT;
            break;
        case TNFW_B_BROKEN:
            tstate.buffer_state = TIFIOCBUF_BROKEN;
            break;
        }
        /* LINTED assignment of 64-bit integer to 32-bit integer */
        tstate.buffer_size = tnf_trace_file_size;
    }
    tstate.trace_stopped = tnfw_b_state & TNFW_B_STOPPED;
    tstate.pidfilter_mode = tnf_drv_state.tnf_pidfilter_mode;
    tstate.pidfilter_size = 0;

    mutex_enter(&pidlock);
    for (procp = practive; procp != NULL; procp = procp->p_next)
        if (PROC_IS_FILTER(procp))
            tstate.pidfilter_size++;
    mutex_exit(&pidlock);

    if (ddi_copyout((caddr_t)&tstate, arg, sizeof (tstate), mode))
        return (EFAULT);
    return (0);
}

static int
tnf_allocbuf(intptr_t arg)
{
    size_t bufsz;

    if (tnf_buf != NULL)
        return (EBUSY);

    bufsz = roundup((size_t)arg, PAGESIZE);
    /*
     * Validate size
     * XXX Take kernel VM into consideration as well
     */
    /* bug fix #4057599 if (bufsz > (physmem << PAGESHIFT) / 2) */
    if (btop(bufsz) > (physmem / 2))
        return (ENOMEM);
    if (bufsz < TNF_TRACE_FILE_MIN)
        bufsz = TNF_TRACE_FILE_MIN;

#if TNF_USE_KMA
    tnf_buf = kmem_zalloc(bufsz, KM_SLEEP);
#else
    /* LINTED cast from 64-bit integer to 32-bit intege */
    tnf_buf = segkp_get(segkp, (int)bufsz,
        KPD_ZERO | KPD_LOCKED | KPD_NO_ANON);
#endif
    if (tnf_buf == NULL)
        return (ENOMEM);

    tnf_trace_file_size = bufsz;
    tnf_trace_init();
    return (0);
}

/*
 * Process a "deallocate buffer" ioctl request.  Tracing must be turned
 * off.  We must clear references to the buffer from the tag sites;
 * invalidate all threads' notions of block ownership; make sure nobody
 * is executing a probe (they might have started before tracing was
 * turned off); and free the buffer.
 */
static int
tnf_deallocbuf(void)
{
    tnf_ops_t *tpdp;
    kthread_t *t;
    tnf_probe_control_t *probep;
    tnf_tag_data_t *tagp;

    if (tnf_drv_state.mapdev_open_count > 0 || tnf_tracing_active)
        return (EBUSY);
    if (tnf_buf == NULL)
        return (ENOMEM);

    /*
     * Make sure nobody is executing a probe.
     * (They could be if they got started while
     * tnf_tracing_active was still on.)  Grab
     * pidlock, and check the busy flag in all
     * TPDP's.
     */
    mutex_enter(&pidlock);
    t = curthread;
    do {
        if (t->t_tnf_tpdp != NULL) {
        /* LINTED pointer cast may result in improper alignment */
            tpdp = (tnf_ops_t *)t->t_tnf_tpdp;
            if (LOCK_HELD(&tpdp->busy)) {
                mutex_exit(&pidlock);
                return (EBUSY);
            }
            tpdp->wcb.tnfw_w_pos.tnfw_w_block = NULL;
            tpdp->wcb.tnfw_w_tag_pos.tnfw_w_block = NULL;
            tpdp->schedule.record_p = NULL;
        }
        t = t->t_next;
    } while (t != curthread);
    mutex_exit(&pidlock);

    /*
     * Zap all references to the buffer we're freeing.
     * Grab mod_lock while walking list to keep it
     * consistent.
     */
    mutex_enter(&mod_lock);
    tagp = (tnf_tag_data_t *)__tnf_tag_list_head;
    while (tagp != NULL) {
        tagp->tag_index = 0;
        tagp = (tnf_tag_data_t *)tagp->tag_version;
    }
    probep = (tnf_probe_control_t *)__tnf_probe_list_head;
    while (probep != NULL) {
        probep->index = 0;
        probep = probep->next;
    }
    mutex_exit(&mod_lock);

    tnfw_b_state = TNFW_B_NOBUFFER | TNFW_B_STOPPED;
#if TNF_USE_KMA
    kmem_free(tnf_buf, tnf_trace_file_size);
#else
    segkp_release(segkp, tnf_buf);
#endif
    tnf_buf = NULL;

    return (0);
}

static int
tnf_settracing(int arg)
{
    if (arg)
        if (tnf_buf == NULL)
            return (ENOMEM);
        else
            tnf_trace_on();
    else
        tnf_trace_off();

#ifdef _TNF_SPEED_TEST
#define NITER   255
    {
        int i;

        for (i = 0; i < NITER; i++)
            TNF_PROBE_0(tnf_speed_0, "tnf", /* CSTYLED */);
        for (i = 0; i < NITER; i++)
            TNF_PROBE_1(tnf_speed_1, "tnf", /* CSTYLED */,
                tnf_long,   long,   i);
        for (i = 0; i < NITER; i++)
            TNF_PROBE_2(tnf_speed_2, "tnf", /* CSTYLED */,
                tnf_long,   long1,  i,
                tnf_long,   long2,  i);
    }
#endif /* _TNF_SPEED_TEST */

    return (0);
}

static int
tnf_getpidstate(caddr_t arg, int mode)
{
    int err = 0;
    pid_t   pid;
    proc_t  *procp;
    int result;

    if (ddi_copyin(arg, (caddr_t)&pid, sizeof (pid), mode))
        return (EFAULT);

    mutex_enter(&pidlock);
    if ((procp = prfind(pid)) != NULL)
        result = PROC_IS_FILTER(procp);
    else
        err = ESRCH;
    mutex_exit(&pidlock);

    if (!err)
        if (ddi_copyout((caddr_t)&result, (caddr_t)arg,
            sizeof (result), mode))
            return (EFAULT);
    return (err);
}

/*ARGSUSED*/
static int
tnf_setpidstate(int filterval, pid_t pid, int mode)
{
    int err = 0;
    proc_t  *procp;

    mutex_enter(&pidlock);
    if ((procp = prfind(pid)) != NULL)
        if (filterval)
            PROC_FILTER_SET(procp);
        else
            PROC_FILTER_CLR(procp);
    else
        err = ESRCH;
    mutex_exit(&pidlock);

    return (err);
}

static int
tnf_pidfilterset(int mode)
{
    tnf_probe_control_t *p;
    tnf_probe_test_func_t   func;

    tnf_drv_state.tnf_pidfilter_mode = mode;

    /* Establish correct test func for each probe */
    if (mode)
        func = tnf_test_2;
    else
        func = tnf_test_1;

    mutex_enter(&mod_lock);
    p = (tnf_probe_control_t *)__tnf_probe_list_head;
    while (p != NULL) {
        if (p->test_func != NULL)
            p->test_func = func;
        p = p->next;
    }
    mutex_exit(&mod_lock);

    return (0);
}

static int
tnf_pidfilterget(caddr_t dest, int mode)
{
    int err = 0;
    int filtercount = 0;
    size_t  sz;
    pid_t   *filterbuf, *bufp;
    proc_t  *procp;

    /* Count how many processes in filter set (upper bound) */
    mutex_enter(&pidlock);
    for (procp = practive; procp != NULL; procp = procp->p_next)
        if (PROC_IS_FILTER(procp))
            filtercount++;
    mutex_exit(&pidlock);

    /* Allocate temp space to hold filter set (upper bound) */
    sz = sizeof (pid_t) * (filtercount + 1);
    filterbuf = kmem_zalloc(sz, KM_SLEEP);

    /*
     * NOTE: The filter set cannot grow between the first and
     * second acquisitions of pidlock.  This is currently true
     * because:
     *  1. /dev/tnfctl is exclusive open, so all driver
     *     control operations, including changing the filter
     *     set and this code, are effectively single-threaded.
     *  2. There is no in-kernel API to manipulate the filter
     *     set (i.e. toggle the on/off bit in a proc struct).
     *  3. The proc filter bit is not inherited across a fork()
     *     operation; the child starts with the bit off.
     * If any of these assumptions is invalidated, a possible
     * solution is to check whether we're overflowing the allocated
     * filterbuf below, and back out and restart from the beginning
     * if so.
     *
     * The code below handles the case when the filter set shrinks
     * due to processes exiting.
     */

    /* Fill in filter set */
    bufp = filterbuf + 1;   /* first word is for count */
    filtercount = 0;    /* recomputed below */
    mutex_enter(&pidlock);
    for (procp = practive; procp != NULL; procp = procp->p_next) {
        if (PROC_IS_FILTER(procp)) {
            filtercount++;
            *bufp++ = procp->p_pid;
        }
    }
    mutex_exit(&pidlock);

    /* Set filtercount */
    *filterbuf = (pid_t)filtercount;

    /* Copy out result */
    if (ddi_copyout((caddr_t)filterbuf, dest, sz, mode))
        err = EFAULT;

    /* Free temp space */
    kmem_free(filterbuf, sz);

    return (err);
}

static int
tnf_getheader(caddr_t arg, int mode)
{
    if (tnf_buf == NULL)
        return (ENOMEM);
    if (ddi_copyout(tnf_buf, arg, TNF_BLOCK_SIZE, mode))
        return (EFAULT);
    return (0);
}

static int
tnf_getblock(caddr_t arg, int mode)
{
    int     err = 0;
    tifiocgblock_t  parms;
    caddr_t     area;
    tnf_block_header_t  *blk;

    if (tnf_buf == NULL)
        return (ENOMEM);
    if (ddi_copyin(arg, (caddr_t)&parms, sizeof (parms), mode))
        return (EFAULT);
    area = tnf_buf + TNF_DIRECTORY_SIZE +
        parms.block_num * TNF_BLOCK_SIZE;
    if (area < tnf_buf + TNF_DIRECTORY_SIZE ||
        area >= tnf_buf + tnf_trace_file_size)
        return (EFAULT);
    /* LINTED pointer cast */
    blk = (tnf_block_header_t *)area;
    /*
     * B-lock the block while we're reading
     */
    if (!lock_try(&blk->B_lock))
        return (EBUSY);
    if (ddi_copyout(area, parms.dst_addr, TNF_BLOCK_SIZE, mode))
        err = EFAULT;
    lock_clear(&blk->B_lock);
    return (err);
}

static int
tnf_getfwzone(caddr_t arg, int mode)
{
    tifiocgfw_t parms;

    if (tnf_buf == NULL)
        return (ENOMEM);
    if (ddi_copyin(arg, (caddr_t)&parms, sizeof (parms), mode))
        return (EFAULT);
    if (ddi_copyout(tnf_buf + TNF_BLOCK_SIZE + parms.start *
        sizeof (tnf_ref32_t), (caddr_t)parms.dst_addr,
        parms.slots * (int)(sizeof (tnf_ref32_t)), mode))
        return (EFAULT);
    return (0);
}

/*ARGSUSED*/
static void *
tnf_test_1(void *tpdp, tnf_probe_control_t *probe_p, tnf_probe_setup_t *sp)
{
    tpdp = (void *)curthread->t_tnf_tpdp;
    if (tpdp != NULL)
        return (tnf_trace_alloc((tnf_ops_t *)tpdp, probe_p, sp));
    return (NULL);
}

/*ARGSUSED*/
static void *
tnf_test_2(void *tpdp, tnf_probe_control_t *probe_p, tnf_probe_setup_t *sp)
{
    tpdp = (void *)curthread->t_tnf_tpdp;
    if (tpdp != NULL && PROC_IS_FILTER(curproc))
        return (tnf_trace_alloc((tnf_ops_t *)tpdp, probe_p, sp));
    return (NULL);
}

#endif /* !NPROBE */