path: root/sys/cddl/dev/dtnfsclient/dtnfsclient.c

/*-
 * Copyright (c) 2009 Robert N. M. Watson
 * All rights reserved.
 *
 * This software was developed at the University of Cambridge Computer
 * Laboratory with support from a grant from Google, Inc.
 *
 * 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("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>

#include <sys/dtrace.h>
#include <sys/dtrace_bsd.h>

#include <nfs/nfsproto.h>

/*
 * dtnfsclient is a DTrace provider that tracks the intent to perform RPCs
 * in the NFS client.  This is not quite the same as RPCs, because NFS may
 * issue multiple RPC transactions in the event that authentication fails,
 * there's a jukebox error, etc.  However, it cleanly represents the logical
 * layer between RPC transmission and vnode/vfs operations, providing access
 * to state linking the two.
 */

static int	dtnfsclient_unload(void);
static void	dtnfsclient_getargdesc(void *, dtrace_id_t, void *,
		    dtrace_argdesc_t *);
static void	dtnfsclient_provide(void *, dtrace_probedesc_t *);
static void	dtnfsclient_destroy(void *, dtrace_id_t, void *);
static void	dtnfsclient_enable(void *, dtrace_id_t, void *);
static void	dtnfsclient_disable(void *, dtrace_id_t, void *);
static void	dtnfsclient_load(void *);

static dtrace_pattr_t dtnfsclient_attr = {
{ DTRACE_STABILITY_STABLE, DTRACE_STABILITY_STABLE, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_STABLE, DTRACE_STABILITY_STABLE, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_STABLE, DTRACE_STABILITY_STABLE, DTRACE_CLASS_COMMON },
};

struct dtnfsclient_rpc {
	char		*nr_v3_name;
	char		*nr_v2_name;	/* Or NULL if none. */

	/*
	 * IDs for the start and done cases, for both NFSv2 and NFSv3.
	 */
	uint32_t	 nr_v2_id_start, nr_v2_id_done;
	uint32_t	 nr_v3_id_start, nr_v3_id_done;
};

/*
 * This table is indexed by NFSv3 procedure number, but also used for NFSv2
 * procedure names.
 */
static struct dtnfsclient_rpc	dtnfsclient_rpcs[NFS_NPROCS] = {
	{ "null", "null" },
	{ "getattr", "getattr" },
	{ "setattr", "setattr" },
	{ "lookup", "lookup" },
	{ "access" },
	{ "readlink", "readlink" },
	{ "read", "read" },
	{ "write", "write" },
	{ "create", "create" },
	{ "mkdir", "mkdir" },
	{ "symlink", "symlink" },
	{ "mknod" },
	{ "remove", "remove" },
	{ "rmdir", "rmdir" },
	{ "rename", "rename" },
	{ "link", "link" },
	{ "readdir", "readdir" },
	{ "readdirplus" },
	{ "fsstat", "statfs" },
	{ "fsinfo" },
	{ "pathconf" },
	{ "commit" },
	{ "noop" },
};

static char	*dtnfsclient_v2modulename = "nfs2";
static char	*dtnfsclient_v3modulename = "nfs3";

static char	*dtnfsclient_start = "start";
static char	*dtnfsclient_done = "done";

static dtrace_pops_t dtnfsclient_pops = {
	dtnfsclient_provide,
	NULL,
	dtnfsclient_enable,
	dtnfsclient_disable,
	NULL,
	NULL,
	dtnfsclient_getargdesc,
	NULL,
	NULL,
	dtnfsclient_destroy
};

static dtrace_provider_id_t	dtnfsclient_id;

/*
 * When tracing on a procedure is enabled, the DTrace ID for the event is
 * stored in one of these two NFS client-allocated arrays; 0 indicates that
 * the event is not being traced so probes should not be called.
 *
 * For simplicity, we allocate both v2 and v3 arrays as NFS_NPROCS, and the
 * v2 array is simply sparse.
 */
extern uint32_t			nfsclient_nfs2_start_probes[NFS_NPROCS];
extern uint32_t			nfsclient_nfs2_done_probes[NFS_NPROCS];

extern uint32_t			nfsclient_nfs3_start_probes[NFS_NPROCS];
extern uint32_t			nfsclient_nfs3_done_probes[NFS_NPROCS];

/*
 * Look up a DTrace probe ID to see if it's associated with a "done" event --
 * if so, we will return a fourth argument type of "int".
 */
static int
dtnfs23_isdoneprobe(dtrace_id_t id)
{
	int i;

	for (i = 0; i < NFS_NPROCS; i++) {
		if (dtnfsclient_rpcs[i].nr_v3_id_done == id ||
		    dtnfsclient_rpcs[i].nr_v2_id_done == id)
			return (1);
	}
	return (0);
}

static void
dtnfsclient_getargdesc(void *arg, dtrace_id_t id, void *parg,
    dtrace_argdesc_t *desc)
{
	const char *p = NULL;

	switch (desc->dtargd_ndx) {
	case 0:
		p = "struct vnode *";
		break;
	case 1:
		p = "struct mbuf *";
		break;
	case 2:
		p = "struct ucred *";
		break;
	case 3:
		p = "int";
		break;
	case 4:
		if (dtnfs23_isdoneprobe(id)) {
			p = "int";
			break;
		}
		/* FALLSTHROUGH */
	default:
		desc->dtargd_ndx = DTRACE_ARGNONE;
		break;
	}
	if (p != NULL)
		strlcpy(desc->dtargd_native, p, sizeof(desc->dtargd_native));
}

static void
dtnfsclient_provide(void *arg, dtrace_probedesc_t *desc)
{
	int i;

	if (desc != NULL)
		return;

	/*
	 * First, register NFSv2 RPC procedures; note sparseness check for
	 * each slot in the NFSv3 procnum-indexed array.
	 */
	for (i = 0; i < NFS_NPROCS; i++) {
		if (dtnfsclient_rpcs[i].nr_v2_name != NULL &&
		    dtrace_probe_lookup(dtnfsclient_id,
		    dtnfsclient_v2modulename, dtnfsclient_rpcs[i].nr_v2_name,
		    dtnfsclient_start) == 0) {
			dtnfsclient_rpcs[i].nr_v2_id_start =
			    dtrace_probe_create(dtnfsclient_id,
			    dtnfsclient_v2modulename,
			    dtnfsclient_rpcs[i].nr_v2_name,
			    dtnfsclient_start, 0,
			    &nfsclient_nfs2_start_probes[i]);
		}
		if (dtnfsclient_rpcs[i].nr_v2_name != NULL &&
		    dtrace_probe_lookup(dtnfsclient_id,
		    dtnfsclient_v2modulename, dtnfsclient_rpcs[i].nr_v2_name,
		    dtnfsclient_done) == 0) {
			dtnfsclient_rpcs[i].nr_v2_id_done = 
			    dtrace_probe_create(dtnfsclient_id,
			    dtnfsclient_v2modulename,
			    dtnfsclient_rpcs[i].nr_v2_name,
			    dtnfsclient_done, 0,
			    &nfsclient_nfs2_done_probes[i]);
		}
	}

	/*
	 * Now, register NFSv3 RPC procedures.
	 */
	for (i = 0; i < NFS_NPROCS; i++) {
		if (dtrace_probe_lookup(dtnfsclient_id,
		    dtnfsclient_v3modulename, dtnfsclient_rpcs[i].nr_v3_name,
		    dtnfsclient_start) == 0) {
			dtnfsclient_rpcs[i].nr_v3_id_start =
			    dtrace_probe_create(dtnfsclient_id,
			    dtnfsclient_v3modulename,
			    dtnfsclient_rpcs[i].nr_v3_name,
			    dtnfsclient_start, 0,
			    &nfsclient_nfs3_start_probes[i]);
		}
		if (dtrace_probe_lookup(dtnfsclient_id,
		    dtnfsclient_v3modulename, dtnfsclient_rpcs[i].nr_v3_name,
		    dtnfsclient_done) == 0) {
			dtnfsclient_rpcs[i].nr_v3_id_done = 
			    dtrace_probe_create(dtnfsclient_id,
			    dtnfsclient_v3modulename,
			    dtnfsclient_rpcs[i].nr_v3_name,
			    dtnfsclient_done, 0,
			    &nfsclient_nfs3_done_probes[i]);
		}
	}
}

static void
dtnfsclient_destroy(void *arg, dtrace_id_t id, void *parg)
{
}

static void
dtnfsclient_enable(void *arg, dtrace_id_t id, void *parg)
{
	uint32_t *p = parg;

	*p = id;
}

static void
dtnfsclient_disable(void *arg, dtrace_id_t id, void *parg)
{
	uint32_t *p = parg;

	*p = 0;
}

static void
dtnfsclient_load(void *dummy)
{

	if (dtrace_register("nfsclient", &dtnfsclient_attr,
	    DTRACE_PRIV_USER, NULL, &dtnfsclient_pops, NULL,
	    &dtnfsclient_id) != 0)
		return;

	dtrace_nfsclient_nfs23_start_probe =
	    (dtrace_nfsclient_nfs23_start_probe_func_t)dtrace_probe;
	dtrace_nfsclient_nfs23_done_probe =
	    (dtrace_nfsclient_nfs23_done_probe_func_t)dtrace_probe;
}


static int
dtnfsclient_unload()
{
	int error = 0;

	dtrace_nfsclient_nfs23_start_probe = NULL;
	dtrace_nfsclient_nfs23_done_probe = NULL;

	if ((error = dtrace_unregister(dtnfsclient_id)) != 0)
		return (error);

	return (error);
}

static int
dtnfsclient_modevent(module_t mod __unused, int type, void *data __unused)
{
	int error = 0;

	switch (type) {
	case MOD_LOAD:
		break;

	case MOD_UNLOAD:
		break;

	case MOD_SHUTDOWN:
		break;

	default:
		error = EOPNOTSUPP;
		break;
	}

	return (error);
}

SYSINIT(dtnfsclient_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
    dtnfsclient_load, NULL);
SYSUNINIT(dtnfsclient_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
    dtnfsclient_unload, NULL);

DEV_MODULE(dtnfsclient, dtnfsclient_modevent, NULL);
MODULE_VERSION(dtnfsclient, 1);
MODULE_DEPEND(dtnfsclient, dtrace, 1, 1, 1);
MODULE_DEPEND(dtnfsclient, opensolaris, 1, 1, 1);