xref: /illumos-gate/usr/src/lib/fm/topo/libtopo/common/svc.c (revision d67944fbe3fa0b31893a7116a09b0718eecf6078)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * This provides the basic mechanisms (str2nvl and nvl2str) for dealing with
29  * the service schema.  The official version of a svc FMRI has the form:
30  *
31  * 	svc://[scope@][system-fqn]/service[:instance][@contract-id]
32  *
33  * Where 'service' is a slash-delimited list of names.  Of these fields, the
34  * scope, constract-id, and system-fqn are rarely used, leaving the much more
35  * common form such as:
36  *
37  * 	svc:///network/ssh:default
38  *
39  * Note that the SMF software typically uses a shorthard form, where the
40  * authority is elided (svc:/network/ssh:default).  As this module deals with
41  * FMA FMRIs, we only support fully specified FMRIs.
42  *
43  * This module does not support enumeration, but implements methods for FMRI
44  * state (present, unusable, service state, and replaced).
45  */
46 
47 #include <fm/topo_mod.h>
48 #include <fm/fmd_fmri.h>
49 #include <sys/fm/protocol.h>
50 #include <topo_method.h>
51 #include <topo_subr.h>
52 #include <alloca.h>
53 #include <assert.h>
54 #include <svc.h>
55 #include <strings.h>
56 #include <libscf.h>
57 
58 static int svc_fmri_nvl2str(topo_mod_t *, tnode_t *, topo_version_t,
59     nvlist_t *, nvlist_t **);
60 static int svc_fmri_str2nvl(topo_mod_t *, tnode_t *, topo_version_t,
61     nvlist_t *, nvlist_t **);
62 static int svc_fmri_present(topo_mod_t *, tnode_t *, topo_version_t,
63     nvlist_t *, nvlist_t **);
64 static int svc_fmri_replaced(topo_mod_t *, tnode_t *, topo_version_t,
65     nvlist_t *, nvlist_t **);
66 static int svc_fmri_service_state(topo_mod_t *, tnode_t *, topo_version_t,
67     nvlist_t *, nvlist_t **);
68 static int svc_fmri_unusable(topo_mod_t *, tnode_t *, topo_version_t,
69     nvlist_t *, nvlist_t **);
70 static int svc_enum(topo_mod_t *, tnode_t *, const char *, topo_instance_t,
71     topo_instance_t, void *, void *);
72 static void svc_release(topo_mod_t *, tnode_t *);
73 
74 static const topo_method_t svc_methods[] = {
75 	{ TOPO_METH_NVL2STR, TOPO_METH_NVL2STR_DESC, TOPO_METH_NVL2STR_VERSION,
76 	    TOPO_STABILITY_INTERNAL, svc_fmri_nvl2str },
77 	{ TOPO_METH_STR2NVL, TOPO_METH_STR2NVL_DESC, TOPO_METH_STR2NVL_VERSION,
78 	    TOPO_STABILITY_INTERNAL, svc_fmri_str2nvl },
79 	{ TOPO_METH_PRESENT, TOPO_METH_PRESENT_DESC, TOPO_METH_PRESENT_VERSION,
80 	    TOPO_STABILITY_INTERNAL, svc_fmri_present },
81 	{ TOPO_METH_REPLACED, TOPO_METH_REPLACED_DESC,
82 	    TOPO_METH_REPLACED_VERSION, TOPO_STABILITY_INTERNAL,
83 	    svc_fmri_replaced },
84 	{ TOPO_METH_SERVICE_STATE, TOPO_METH_SERVICE_STATE_DESC,
85 	    TOPO_METH_SERVICE_STATE_VERSION, TOPO_STABILITY_INTERNAL,
86 	    svc_fmri_service_state },
87 	{ TOPO_METH_UNUSABLE, TOPO_METH_UNUSABLE_DESC,
88 	    TOPO_METH_UNUSABLE_VERSION, TOPO_STABILITY_INTERNAL,
89 	    svc_fmri_unusable },
90 	{ NULL }
91 };
92 
93 static const topo_modops_t svc_ops =
94 	{ svc_enum, svc_release };
95 static const topo_modinfo_t svc_info =
96 	{ "svc", FM_FMRI_SCHEME_SVC, SVC_VERSION, &svc_ops };
97 
98 static int
99 svc_error(topo_mod_t *mod)
100 {
101 	switch (scf_error()) {
102 	case SCF_ERROR_NO_MEMORY:
103 		return (topo_mod_seterrno(mod, EMOD_NOMEM));
104 
105 	default:
106 		return (topo_mod_seterrno(mod, EMOD_UNKNOWN));
107 	}
108 }
109 
110 static scf_handle_t *
111 svc_get_handle(topo_mod_t *mod)
112 {
113 	scf_handle_t *hdl = topo_mod_getspecific(mod);
114 
115 	if (hdl != NULL)
116 		return (hdl);
117 
118 	if ((hdl = scf_handle_create(SCF_VERSION)) == NULL) {
119 		(void) svc_error(mod);
120 		return (NULL);
121 	}
122 
123 	if (scf_handle_bind(hdl) != 0) {
124 		scf_handle_destroy(hdl);
125 		(void) svc_error(mod);
126 		return (NULL);
127 	}
128 
129 	topo_mod_setspecific(mod, hdl);
130 
131 	return (hdl);
132 }
133 
134 int
135 svc_init(topo_mod_t *mod, topo_version_t version)
136 {
137 	if (version != SVC_VERSION)
138 		return (topo_mod_seterrno(mod, EMOD_VER_NEW));
139 
140 	if (topo_mod_register(mod, &svc_info, TOPO_VERSION) != 0) {
141 		topo_mod_dprintf(mod, "failed to register svc_info: "
142 		    "%s\n", topo_mod_errmsg(mod));
143 		return (-1);
144 	}
145 
146 	return (0);
147 }
148 
149 void
150 svc_fini(topo_mod_t *mod)
151 {
152 	scf_handle_t *hdl = topo_mod_getspecific(mod);
153 
154 	if (hdl != NULL)
155 		scf_handle_destroy(hdl);
156 
157 	topo_mod_unregister(mod);
158 }
159 
160 /*ARGSUSED*/
161 static int
162 svc_enum(topo_mod_t *mod, tnode_t *pnode, const char *name,
163     topo_instance_t min, topo_instance_t max, void *notused1, void *notused2)
164 {
165 	(void) topo_method_register(mod, pnode, svc_methods);
166 	return (0);
167 }
168 
169 static void
170 svc_release(topo_mod_t *mod, tnode_t *node)
171 {
172 	topo_method_unregister_all(mod, node);
173 }
174 
175 static boolean_t
176 svc_component_valid(const char *str)
177 {
178 	if (str == NULL)
179 		return (B_TRUE);
180 
181 	if (*str == '\0')
182 		return (B_FALSE);
183 
184 	if (strpbrk(str, "@/:") != NULL)
185 		return (B_FALSE);
186 
187 	return (B_TRUE);
188 }
189 
190 /*ARGSUSED*/
191 static int
192 svc_fmri_nvl2str(topo_mod_t *mod, tnode_t *node, topo_version_t version,
193     nvlist_t *nvl, nvlist_t **out)
194 {
195 	uint8_t scheme_version;
196 	char *scope = NULL;
197 	char *fqn = NULL;
198 	char *contract = NULL;
199 	char *instance = NULL;
200 	char *service;
201 	int err;
202 	char *buf = NULL;
203 	size_t buflen = 0;
204 	ssize_t size = 0;
205 	nvlist_t *fmristr;
206 
207 	if (version > TOPO_METH_NVL2STR_VERSION)
208 		return (topo_mod_seterrno(mod, EMOD_VER_NEW));
209 
210 	if (nvlist_lookup_uint8(nvl, FM_VERSION, &scheme_version) != 0 ||
211 	    scheme_version > FM_SVC_SCHEME_VERSION)
212 		return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
213 
214 	/*
215 	 * Check for optional members.
216 	 */
217 	err = nvlist_lookup_string(nvl, FM_FMRI_SVC_INSTANCE, &instance);
218 	if ((err != 0 && err != ENOENT) || !svc_component_valid(instance))
219 		return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
220 	err = nvlist_lookup_string(nvl, FM_FMRI_SVC_AUTH_SCOPE, &scope);
221 	if ((err != 0 && err != ENOENT) || !svc_component_valid(scope))
222 		return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
223 	err = nvlist_lookup_string(nvl, FM_FMRI_SVC_AUTH_SYSTEM_FQN, &fqn);
224 	if ((err != 0 && err != ENOENT) || !svc_component_valid(scope))
225 		return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
226 	err = nvlist_lookup_string(nvl, FM_FMRI_SVC_CONTRACT_ID, &contract);
227 	if ((err != 0 && err != ENOENT) || !svc_component_valid(contract))
228 		return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
229 
230 	/*
231 	 * Get the service name.
232 	 */
233 	if (nvlist_lookup_string(nvl, FM_FMRI_SVC_NAME, &service) != 0)
234 		return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
235 
236 	/*
237 	 * We make two passes through this code.  The first time through we
238 	 * calculate the size of buffer that we'll need, and the second time
239 	 * through we fill it in.
240 	 */
241 again:
242 	/*
243 	 * svc://[scope@][system-fqn]
244 	 */
245 	topo_fmristr_build(&size, buf, buflen, FM_FMRI_SCHEME_SVC,
246 	    NULL, "://");
247 	topo_fmristr_build(&size, buf, buflen, scope, NULL, "@");
248 	topo_fmristr_build(&size, buf, buflen, fqn, NULL, NULL);
249 
250 	/* svc path */
251 	if (*service == '\0')
252 		return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
253 
254 	topo_fmristr_build(&size, buf, buflen, service, "/", NULL);
255 
256 	/* [:instance][@contract-id] */
257 	topo_fmristr_build(&size, buf, buflen, instance, ":", NULL);
258 	topo_fmristr_build(&size, buf, buflen, contract, "@", NULL);
259 
260 	if (buf == NULL) {
261 		if ((buf = topo_mod_alloc(mod, size + 1)) == NULL)
262 			return (topo_mod_seterrno(mod, EMOD_NOMEM));
263 
264 		buflen = size + 1;
265 		size = 0;
266 		goto again;
267 	}
268 
269 	/*
270 	 * Construct the nvlist to return as the result.
271 	 */
272 	if (topo_mod_nvalloc(mod, &fmristr, NV_UNIQUE_NAME) != 0) {
273 		topo_mod_strfree(mod, buf);
274 		return (topo_mod_seterrno(mod, EMOD_NOMEM));
275 	}
276 
277 	if (nvlist_add_string(fmristr, "fmri-string", buf) != 0) {
278 		topo_mod_strfree(mod, buf);
279 		nvlist_free(fmristr);
280 		return (topo_mod_seterrno(mod, EMOD_NOMEM));
281 	}
282 	topo_mod_strfree(mod, buf);
283 	*out = fmristr;
284 
285 	return (0);
286 }
287 
288 /*ARGSUSED*/
289 static int
290 svc_fmri_str2nvl(topo_mod_t *mod, tnode_t *node, topo_version_t version,
291     nvlist_t *in, nvlist_t **out)
292 {
293 	nvlist_t *fmri;
294 	char *str, *loc, val;
295 
296 	if (version > TOPO_METH_STR2NVL_VERSION)
297 		return (topo_mod_seterrno(mod, EMOD_VER_NEW));
298 
299 	if (nvlist_lookup_string(in, "fmri-string", &str) != 0)
300 		return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
301 
302 	if (strncmp(str, "svc://", 6) != 0)
303 		return (topo_mod_seterrno(mod, EMOD_FMRI_MALFORM));
304 
305 	if (topo_mod_nvalloc(mod, &fmri, NV_UNIQUE_NAME) != 0)
306 		return (topo_mod_seterrno(mod, EMOD_NOMEM));
307 
308 	str += 6;
309 	if ((loc = strpbrk(str, "@/")) == NULL)
310 		goto malformed;
311 
312 	if (*loc == '@') {
313 		/* scope */
314 		*loc = '\0';
315 		if (!svc_component_valid(str)) {
316 			*loc = '@';
317 			goto malformed;
318 		}
319 
320 		if (nvlist_add_string(fmri, FM_FMRI_SVC_AUTH_SCOPE, str) != 0) {
321 			*loc = '@';
322 			goto nomem;
323 		}
324 
325 		*loc = '@';
326 		str = loc + 1;
327 		if ((loc = strchr(str, '/')) == NULL)
328 			goto malformed;
329 	}
330 
331 	if (loc != str) {
332 		/* system-fqn */
333 		*loc = '\0';
334 		if (!svc_component_valid(str)) {
335 			*loc = '/';
336 			goto malformed;
337 		}
338 
339 		if (nvlist_add_string(fmri, FM_FMRI_SVC_AUTH_SYSTEM_FQN,
340 		    str) != 0) {
341 			*loc = '/';
342 			goto nomem;
343 		}
344 
345 		*loc = '/';
346 	}
347 
348 	str = loc + 1;
349 	loc = strpbrk(str, ":@");
350 
351 	if (str[0] == '\0' || loc == str)
352 		goto malformed;
353 
354 	if (loc != NULL) {
355 		val = *loc;
356 		*loc = '\0';
357 	}
358 
359 	/* service name */
360 	if (nvlist_add_string(fmri, FM_FMRI_SVC_NAME, str) != 0) {
361 		if (loc != NULL)
362 			*loc = val;
363 		goto nomem;
364 	}
365 
366 	if (loc != NULL)
367 		*loc = val;
368 
369 	if (loc != NULL && *loc == ':') {
370 		/* instance */
371 		str = loc + 1;
372 		if (str[0] == '\0' || str[0] == '@')
373 			goto malformed;
374 
375 		loc = strchr(str, '@');
376 		if (loc != NULL)
377 			*loc = '\0';
378 
379 		if (nvlist_add_string(fmri, FM_FMRI_SVC_INSTANCE,
380 		    str) != 0) {
381 			if (loc != NULL)
382 				*loc = '@';
383 			goto nomem;
384 		}
385 
386 		if (loc != NULL)
387 			*loc = '@';
388 	}
389 
390 	if (loc != NULL) {
391 		/* contract-id */
392 		assert(*loc == '@');
393 		str = loc + 1;
394 		if (str[0] == '\0')
395 			goto malformed;
396 
397 		if (nvlist_add_string(fmri, FM_FMRI_SVC_CONTRACT_ID,
398 		    str) != 0) {
399 			goto nomem;
400 		}
401 	}
402 
403 	if (nvlist_add_uint8(fmri, FM_VERSION, FM_SVC_SCHEME_VERSION) != 0 ||
404 	    nvlist_add_string(fmri, FM_FMRI_SCHEME, FM_FMRI_SCHEME_SVC) != 0)
405 		goto nomem;
406 
407 	*out = fmri;
408 	return (0);
409 
410 malformed:
411 	nvlist_free(fmri);
412 	return (topo_mod_seterrno(mod, EMOD_FMRI_MALFORM));
413 
414 nomem:
415 	nvlist_free(fmri);
416 	return (topo_mod_seterrno(mod, EMOD_NOMEM));
417 }
418 
419 /*
420  * This common function is shared by all consumers (present, unusable, and
421  * service_state).  It returns one of the FMD_SERVICE_STATE_* states, where
422  * FMD_SERVICE_STATE_UNKNOWN means that the FMRI is not present.
423  */
424 static int
425 svc_get_state(topo_mod_t *mod, nvlist_t *fmri, boolean_t presence_only,
426     int *ret)
427 {
428 	scf_handle_t *hdl;
429 	uint8_t fmversion;
430 	char *instance, *name;
431 	scf_service_t *svc = NULL;
432 	scf_scope_t *scope = NULL;
433 	scf_instance_t *inst = NULL;
434 	scf_property_t *prop = NULL;
435 	scf_iter_t *iter = NULL;
436 	scf_value_t *val = NULL;
437 	scf_propertygroup_t *pg = NULL;
438 	int err, retval = 0;
439 	ssize_t len;
440 	char *state;
441 
442 	if ((hdl = svc_get_handle(mod)) == NULL)
443 		return (-1);
444 
445 	if (nvlist_lookup_uint8(fmri, FM_VERSION, &fmversion) != 0 ||
446 	    fmversion > FM_SVC_SCHEME_VERSION ||
447 	    nvlist_lookup_string(fmri, FM_FMRI_SVC_NAME, &name) != 0)
448 		return (topo_mod_seterrno(mod, EMOD_FMRI_MALFORM));
449 
450 	if ((svc = scf_service_create(hdl)) == NULL ||
451 	    (inst = scf_instance_create(hdl)) == NULL ||
452 	    (scope = scf_scope_create(hdl)) == NULL ||
453 	    (prop = scf_property_create(hdl)) == NULL ||
454 	    (iter = scf_iter_create(hdl)) == NULL ||
455 	    (pg = scf_pg_create(hdl)) == NULL ||
456 	    (val = scf_value_create(hdl)) == NULL)
457 		goto error;
458 
459 	if (scf_handle_get_scope(hdl, SCF_SCOPE_LOCAL, scope) != 0)
460 		goto error;
461 
462 	/*
463 	 * If we fail to get the service due to _DELETED or _NOT_FOUND, then we
464 	 * treat this as not present.
465 	 */
466 	if (scf_scope_get_service(scope, name, svc) != 0) {
467 		err = scf_error();
468 		if (err == SCF_ERROR_NOT_FOUND || err == SCF_ERROR_DELETED) {
469 			*ret = FMD_SERVICE_STATE_UNKNOWN;
470 			goto out;
471 		} else {
472 			goto error;
473 		}
474 	}
475 
476 	/*
477 	 * If there is no instance, then it is always present, and always
478 	 * usuable.
479 	 */
480 	if (nvlist_lookup_string(fmri, FM_FMRI_SVC_INSTANCE, &instance) != 0) {
481 		*ret = FMD_SERVICE_STATE_OK;
482 		goto out;
483 	}
484 
485 	/*
486 	 * Again, check for _DELETED or _NOT_FOUND.
487 	 */
488 	if (scf_service_get_instance(svc, instance, inst) != 0) {
489 		err = scf_error();
490 		if (err == SCF_ERROR_NOT_FOUND || err == SCF_ERROR_DELETED) {
491 			*ret = FMD_SERVICE_STATE_UNKNOWN;
492 			goto out;
493 		} else {
494 			goto error;
495 		}
496 	}
497 
498 	/*
499 	 * For presence, we are done.  Otherwise, we need to get the current
500 	 * state of the instance.
501 	 */
502 	if (presence_only) {
503 		*ret = FMD_SERVICE_STATE_OK;
504 		goto out;
505 	}
506 
507 	if (scf_instance_get_pg(inst, SCF_PG_RESTARTER, pg) != 0 ||
508 	    scf_pg_get_property(pg, SCF_PROPERTY_STATE, prop) != 0 ||
509 	    scf_iter_property_values(iter, prop) != 0 ||
510 	    scf_iter_next_value(iter, val) != 1)
511 		goto error;
512 
513 	if ((len = scf_value_get_astring(val, NULL, 0)) < 0)
514 		goto error;
515 
516 	state = alloca(len + 1);
517 	if (scf_value_get_astring(val, state, len + 1) < 0)
518 		goto error;
519 
520 	if (strcmp(state, SCF_STATE_STRING_MAINT) == 0)
521 		*ret = FMD_SERVICE_STATE_UNUSABLE;
522 	else if (strcmp(state, SCF_STATE_STRING_DEGRADED) == 0)
523 		*ret = FMD_SERVICE_STATE_DEGRADED;
524 	else
525 		*ret = FMD_SERVICE_STATE_OK;
526 	goto out;
527 
528 error:
529 	retval = -1;
530 out:
531 	scf_value_destroy(val);
532 	scf_pg_destroy(pg);
533 	scf_iter_destroy(iter);
534 	scf_property_destroy(prop);
535 	scf_instance_destroy(inst);
536 	scf_scope_destroy(scope);
537 	scf_service_destroy(svc);
538 	return (retval);
539 }
540 
541 /*ARGSUSED*/
542 static int
543 svc_fmri_present(topo_mod_t *mod, tnode_t *node, topo_version_t version,
544     nvlist_t *in, nvlist_t **out)
545 {
546 	int state;
547 
548 	if (version > TOPO_METH_PRESENT_VERSION)
549 		return (topo_mod_seterrno(mod, EMOD_VER_NEW));
550 
551 	if (svc_get_state(mod, in, B_TRUE, &state) != 0)
552 		return (-1);
553 
554 	if (topo_mod_nvalloc(mod, out, NV_UNIQUE_NAME) != 0)
555 		return (topo_mod_seterrno(mod, EMOD_NVL_INVAL));
556 	if (nvlist_add_uint32(*out, TOPO_METH_PRESENT_RET,
557 	    state != FMD_SERVICE_STATE_UNKNOWN) != 0) {
558 		nvlist_free(*out);
559 		return (topo_mod_seterrno(mod, EMOD_NVL_INVAL));
560 	}
561 
562 	return (0);
563 }
564 
565 /*ARGSUSED*/
566 static int
567 svc_fmri_replaced(topo_mod_t *mod, tnode_t *node, topo_version_t version,
568     nvlist_t *in, nvlist_t **out)
569 {
570 	int state;
571 
572 	if (version > TOPO_METH_REPLACED_VERSION)
573 		return (topo_mod_seterrno(mod, EMOD_VER_NEW));
574 
575 	if (svc_get_state(mod, in, B_TRUE, &state) != 0)
576 		return (-1);
577 
578 	if (topo_mod_nvalloc(mod, out, NV_UNIQUE_NAME) != 0)
579 		return (topo_mod_seterrno(mod, EMOD_NVL_INVAL));
580 	if (nvlist_add_uint32(*out, TOPO_METH_REPLACED_RET,
581 	    state == FMD_SERVICE_STATE_UNKNOWN ?
582 	    FMD_OBJ_STATE_NOT_PRESENT : FMD_OBJ_STATE_UNKNOWN) != 0) {
583 		nvlist_free(*out);
584 		return (topo_mod_seterrno(mod, EMOD_NVL_INVAL));
585 	}
586 
587 	return (0);
588 }
589 
590 /*ARGSUSED*/
591 static int
592 svc_fmri_service_state(topo_mod_t *mod, tnode_t *node, topo_version_t version,
593     nvlist_t *in, nvlist_t **out)
594 {
595 	int state;
596 
597 	if (version > TOPO_METH_SERVICE_STATE_VERSION)
598 		return (topo_mod_seterrno(mod, EMOD_VER_NEW));
599 
600 	if (svc_get_state(mod, in, B_FALSE, &state) != 0)
601 		return (-1);
602 
603 	if (topo_mod_nvalloc(mod, out, NV_UNIQUE_NAME) != 0)
604 		return (topo_mod_seterrno(mod, EMOD_NVL_INVAL));
605 	if (nvlist_add_uint32(*out, TOPO_METH_SERVICE_STATE_RET,
606 	    state) != 0) {
607 		nvlist_free(*out);
608 		return (topo_mod_seterrno(mod, EMOD_NVL_INVAL));
609 	}
610 
611 	return (0);
612 }
613 
614 /*ARGSUSED*/
615 static int
616 svc_fmri_unusable(topo_mod_t *mod, tnode_t *node, topo_version_t version,
617     nvlist_t *in, nvlist_t **out)
618 {
619 	int state;
620 
621 	if (version > TOPO_METH_UNUSABLE_VERSION)
622 		return (topo_mod_seterrno(mod, EMOD_VER_NEW));
623 
624 	if (svc_get_state(mod, in, B_FALSE, &state) != 0)
625 		return (-1);
626 
627 	if (topo_mod_nvalloc(mod, out, NV_UNIQUE_NAME) != 0)
628 		return (topo_mod_seterrno(mod, EMOD_NVL_INVAL));
629 	if (nvlist_add_uint32(*out, TOPO_METH_UNUSABLE_RET,
630 	    (state == FMD_SERVICE_STATE_UNKNOWN ||
631 	    state == FMD_SERVICE_STATE_UNUSABLE)) != 0) {
632 		nvlist_free(*out);
633 		return (topo_mod_seterrno(mod, EMOD_NVL_INVAL));
634 	}
635 
636 	return (0);
637 }
638