common/dtrace/systrace.c

	systrace.c revision b9e93c10c0a2a4bb069d38bb311021a9478c4711
/*
 * 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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


#include <sys/dtrace.h>
#include <sys/systrace.h>
#include <sys/stat.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/atomic.h>

#define SYSTRACE_ARTIFICIAL_FRAMES  1

#define SYSTRACE_SHIFT          16
#define SYSTRACE_ISENTRY(x)     ((int)(x) >> SYSTRACE_SHIFT)
#define SYSTRACE_SYSNUM(x)      ((int)(x) & ((1 << SYSTRACE_SHIFT) - 1))
#define SYSTRACE_ENTRY(id)      ((1 << SYSTRACE_SHIFT) | (id))
#define SYSTRACE_RETURN(id)     (id)

#if ((1 << SYSTRACE_SHIFT) <= NSYSCALL)
#error 1 << SYSTRACE_SHIFT must exceed number of system calls
#endif

static dev_info_t *systrace_devi;
static dtrace_provider_id_t systrace_id;

static void
systrace_init(struct sysent *actual, systrace_sysent_t **interposed)
{
    systrace_sysent_t *sysent = *interposed;
    int i;

    if (sysent == NULL) {
        *interposed = sysent = kmem_zalloc(sizeof (systrace_sysent_t) *
            NSYSCALL, KM_SLEEP);
    }

    for (i = 0; i < NSYSCALL; i++) {
        struct sysent *a = &actual[i];
        systrace_sysent_t *s = &sysent[i];

        if (LOADABLE_SYSCALL(a) && !LOADED_SYSCALL(a))
            continue;

        if (a->sy_callc == dtrace_systrace_syscall)
            continue;

#ifdef _SYSCALL32_IMPL
        if (a->sy_callc == dtrace_systrace_syscall32)
            continue;
#endif

        s->stsy_underlying = a->sy_callc;
    }
}

/*ARGSUSED*/
static void
systrace_provide(void *arg, const dtrace_probedesc_t *desc)
{
    int i;

    if (desc != NULL)
        return;

    systrace_init(sysent, &systrace_sysent);
#ifdef _SYSCALL32_IMPL
    systrace_init(sysent32, &systrace_sysent32);
#endif

    for (i = 0; i < NSYSCALL; i++) {
        if (systrace_sysent[i].stsy_underlying == NULL)
            continue;

        if (dtrace_probe_lookup(systrace_id, NULL,
            syscallnames[i], "entry") != 0)
            continue;

        (void) dtrace_probe_create(systrace_id, NULL, syscallnames[i],
            "entry", SYSTRACE_ARTIFICIAL_FRAMES,
            (void *)((uintptr_t)SYSTRACE_ENTRY(i)));
        (void) dtrace_probe_create(systrace_id, NULL, syscallnames[i],
            "return", SYSTRACE_ARTIFICIAL_FRAMES,
            (void *)((uintptr_t)SYSTRACE_RETURN(i)));

        systrace_sysent[i].stsy_entry = DTRACE_IDNONE;
        systrace_sysent[i].stsy_return = DTRACE_IDNONE;
#ifdef _SYSCALL32_IMPL
        systrace_sysent32[i].stsy_entry = DTRACE_IDNONE;
        systrace_sysent32[i].stsy_return = DTRACE_IDNONE;
#endif
    }
}

/*ARGSUSED*/
static void
systrace_destroy(void *arg, dtrace_id_t id, void *parg)
{
    int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);

    /*
     * There's nothing to do here but assert that we have actually been
     * disabled.
     */
    if (SYSTRACE_ISENTRY((uintptr_t)parg)) {
        ASSERT(systrace_sysent[sysnum].stsy_entry == DTRACE_IDNONE);
#ifdef _SYSCALL32_IMPL
        ASSERT(systrace_sysent32[sysnum].stsy_entry == DTRACE_IDNONE);
#endif
    } else {
        ASSERT(systrace_sysent[sysnum].stsy_return == DTRACE_IDNONE);
#ifdef _SYSCALL32_IMPL
        ASSERT(systrace_sysent32[sysnum].stsy_return == DTRACE_IDNONE);
#endif
    }
}

/*ARGSUSED*/
static int
systrace_enable(void *arg, dtrace_id_t id, void *parg)
{
    int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);
    int enabled = (systrace_sysent[sysnum].stsy_entry != DTRACE_IDNONE ||
        systrace_sysent[sysnum].stsy_return != DTRACE_IDNONE);

    if (SYSTRACE_ISENTRY((uintptr_t)parg)) {
        systrace_sysent[sysnum].stsy_entry = id;
#ifdef _SYSCALL32_IMPL
        systrace_sysent32[sysnum].stsy_entry = id;
#endif
    } else {
        systrace_sysent[sysnum].stsy_return = id;
#ifdef _SYSCALL32_IMPL
        systrace_sysent32[sysnum].stsy_return = id;
#endif
    }

    if (enabled) {
        ASSERT(sysent[sysnum].sy_callc == dtrace_systrace_syscall);
        return (0);
    }

    (void) casptr(&sysent[sysnum].sy_callc,
        (void *)systrace_sysent[sysnum].stsy_underlying,
        (void *)dtrace_systrace_syscall);
#ifdef _SYSCALL32_IMPL
    (void) casptr(&sysent32[sysnum].sy_callc,
        (void *)systrace_sysent32[sysnum].stsy_underlying,
        (void *)dtrace_systrace_syscall32);
#endif
    return (0);
}

/*ARGSUSED*/
static void
systrace_disable(void *arg, dtrace_id_t id, void *parg)
{
    int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);
    int disable = (systrace_sysent[sysnum].stsy_entry == DTRACE_IDNONE ||
        systrace_sysent[sysnum].stsy_return == DTRACE_IDNONE);

    if (disable) {
        (void) casptr(&sysent[sysnum].sy_callc,
            (void *)dtrace_systrace_syscall,
            (void *)systrace_sysent[sysnum].stsy_underlying);

#ifdef _SYSCALL32_IMPL
        (void) casptr(&sysent32[sysnum].sy_callc,
            (void *)dtrace_systrace_syscall32,
            (void *)systrace_sysent32[sysnum].stsy_underlying);
#endif
    }

    if (SYSTRACE_ISENTRY((uintptr_t)parg)) {
        systrace_sysent[sysnum].stsy_entry = DTRACE_IDNONE;
#ifdef _SYSCALL32_IMPL
        systrace_sysent32[sysnum].stsy_entry = DTRACE_IDNONE;
#endif
    } else {
        systrace_sysent[sysnum].stsy_return = DTRACE_IDNONE;
#ifdef _SYSCALL32_IMPL
        systrace_sysent32[sysnum].stsy_return = DTRACE_IDNONE;
#endif
    }
}

static dtrace_pattr_t systrace_attr = {
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
};

static dtrace_pops_t systrace_pops = {
    systrace_provide,
    NULL,
    systrace_enable,
    systrace_disable,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    systrace_destroy
};

static int
systrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
    switch (cmd) {
    case DDI_ATTACH:
        break;
    case DDI_RESUME:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }

    systrace_probe = (void (*)())dtrace_probe;
    membar_enter();

    if (ddi_create_minor_node(devi, "systrace", S_IFCHR, 0,
        DDI_PSEUDO, NULL) == DDI_FAILURE ||
        dtrace_register("syscall", &systrace_attr, DTRACE_PRIV_USER, NULL,
        &systrace_pops, NULL, &systrace_id) != 0) {
        systrace_probe = systrace_stub;
        ddi_remove_minor_node(devi, NULL);
        return (DDI_FAILURE);
    }

    ddi_report_dev(devi);
    systrace_devi = devi;

    return (DDI_SUCCESS);
}

static int
systrace_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
    switch (cmd) {
    case DDI_DETACH:
        break;
    case DDI_SUSPEND:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }

    if (dtrace_unregister(systrace_id) != 0)
        return (DDI_FAILURE);

    ddi_remove_minor_node(devi, NULL);
    systrace_probe = systrace_stub;
    return (DDI_SUCCESS);
}

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

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

/*ARGSUSED*/
static int
systrace_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
{
    return (0);
}

static struct cb_ops systrace_cb_ops = {
    systrace_open,      /* open */
    nodev,          /* close */
    nulldev,        /* strategy */
    nulldev,        /* print */
    nodev,          /* dump */
    nodev,          /* read */
    nodev,          /* write */
    nodev,          /* ioctl */
    nodev,          /* devmap */
    nodev,          /* mmap */
    nodev,          /* segmap */
    nochpoll,       /* poll */
    ddi_prop_op,        /* cb_prop_op */
    0,          /* streamtab  */
    D_NEW | D_MP        /* Driver compatibility flag */
};

static struct dev_ops systrace_ops = {
    DEVO_REV,       /* devo_rev, */
    0,          /* refcnt  */
    systrace_info,      /* get_dev_info */
    nulldev,        /* identify */
    nulldev,        /* probe */
    systrace_attach,    /* attach */
    systrace_detach,    /* detach */
    nodev,          /* reset */
    &systrace_cb_ops,   /* driver operations */
    NULL,           /* bus operations */
    nodev,          /* dev power */
    ddi_quiesce_not_needed,     /* quiesce */
};

/*
 * Module linkage information for the kernel.
 */
static struct modldrv modldrv = {
    &mod_driverops,     /* module type (this is a pseudo driver) */
    "System Call Tracing",  /* name of module */
    &systrace_ops,      /* driver ops */
};

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

int
_init(void)
{
    return (mod_install(&modlinkage));
}

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

int
_fini(void)
{
    return (mod_remove(&modlinkage));
}