xref: /freebsd/cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.c (revision 193d9e768ba63fcfb187cfd17f461f7d41345048)
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 2006 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 /*
27  * Copyright (c) 2013, Joyent, Inc.  All rights reserved.
28  */
29 
30 #include <sys/types.h>
31 #ifdef illumos
32 #include <sys/sysmacros.h>
33 #endif
34 
35 #include <assert.h>
36 #include <limits.h>
37 #include <strings.h>
38 #include <stdlib.h>
39 #ifdef illumos
40 #include <alloca.h>
41 #endif
42 #include <unistd.h>
43 #include <errno.h>
44 
45 #include <dt_provider.h>
46 #include <dt_module.h>
47 #include <dt_string.h>
48 #include <dt_list.h>
49 #include <dt_pid.h>
50 #include <dtrace.h>
51 
52 static dt_provider_t *
53 dt_provider_insert(dtrace_hdl_t *dtp, dt_provider_t *pvp, uint_t h)
54 {
55 	dt_list_append(&dtp->dt_provlist, pvp);
56 
57 	pvp->pv_next = dtp->dt_provs[h];
58 	dtp->dt_provs[h] = pvp;
59 	dtp->dt_nprovs++;
60 
61 	return (pvp);
62 }
63 
64 dt_provider_t *
65 dt_provider_lookup(dtrace_hdl_t *dtp, const char *name)
66 {
67 	uint_t h = dt_strtab_hash(name, NULL) % dtp->dt_provbuckets;
68 	dtrace_providerdesc_t desc;
69 	dt_provider_t *pvp;
70 
71 	for (pvp = dtp->dt_provs[h]; pvp != NULL; pvp = pvp->pv_next) {
72 		if (strcmp(pvp->pv_desc.dtvd_name, name) == 0)
73 			return (pvp);
74 	}
75 
76 	if (strisglob(name) || name[0] == '\0') {
77 		(void) dt_set_errno(dtp, EDT_NOPROV);
78 		return (NULL);
79 	}
80 
81 	bzero(&desc, sizeof (desc));
82 	(void) strlcpy(desc.dtvd_name, name, DTRACE_PROVNAMELEN);
83 
84 	if (dt_ioctl(dtp, DTRACEIOC_PROVIDER, &desc) == -1) {
85 		(void) dt_set_errno(dtp, errno == ESRCH ? EDT_NOPROV : errno);
86 		return (NULL);
87 	}
88 
89 	if ((pvp = dt_provider_create(dtp, name)) == NULL)
90 		return (NULL); /* dt_errno is set for us */
91 
92 	bcopy(&desc, &pvp->pv_desc, sizeof (desc));
93 	pvp->pv_flags |= DT_PROVIDER_IMPL;
94 	return (pvp);
95 }
96 
97 dt_provider_t *
98 dt_provider_create(dtrace_hdl_t *dtp, const char *name)
99 {
100 	dt_provider_t *pvp;
101 
102 	if ((pvp = dt_zalloc(dtp, sizeof (dt_provider_t))) == NULL)
103 		return (NULL);
104 
105 	(void) strlcpy(pvp->pv_desc.dtvd_name, name, DTRACE_PROVNAMELEN);
106 	pvp->pv_probes = dt_idhash_create(pvp->pv_desc.dtvd_name, NULL, 0, 0);
107 	pvp->pv_gen = dtp->dt_gen;
108 	pvp->pv_hdl = dtp;
109 
110 	if (pvp->pv_probes == NULL) {
111 		dt_free(dtp, pvp);
112 		(void) dt_set_errno(dtp, EDT_NOMEM);
113 		return (NULL);
114 	}
115 
116 	pvp->pv_desc.dtvd_attr.dtpa_provider = _dtrace_prvattr;
117 	pvp->pv_desc.dtvd_attr.dtpa_mod = _dtrace_prvattr;
118 	pvp->pv_desc.dtvd_attr.dtpa_func = _dtrace_prvattr;
119 	pvp->pv_desc.dtvd_attr.dtpa_name = _dtrace_prvattr;
120 	pvp->pv_desc.dtvd_attr.dtpa_args = _dtrace_prvattr;
121 
122 	return (dt_provider_insert(dtp, pvp,
123 	    dt_strtab_hash(name, NULL) % dtp->dt_provbuckets));
124 }
125 
126 void
127 dt_provider_destroy(dtrace_hdl_t *dtp, dt_provider_t *pvp)
128 {
129 	dt_provider_t **pp;
130 	uint_t h;
131 
132 	assert(pvp->pv_hdl == dtp);
133 
134 	h = dt_strtab_hash(pvp->pv_desc.dtvd_name, NULL) % dtp->dt_provbuckets;
135 	pp = &dtp->dt_provs[h];
136 
137 	while (*pp != NULL && *pp != pvp)
138 		pp = &(*pp)->pv_next;
139 
140 	assert(*pp != NULL && *pp == pvp);
141 	*pp = pvp->pv_next;
142 
143 	dt_list_delete(&dtp->dt_provlist, pvp);
144 	dtp->dt_nprovs--;
145 
146 	if (pvp->pv_probes != NULL)
147 		dt_idhash_destroy(pvp->pv_probes);
148 
149 	dt_node_link_free(&pvp->pv_nodes);
150 	dt_free(dtp, pvp->pv_xrefs);
151 	dt_free(dtp, pvp);
152 }
153 
154 int
155 dt_provider_xref(dtrace_hdl_t *dtp, dt_provider_t *pvp, id_t id)
156 {
157 	size_t oldsize = BT_SIZEOFMAP(pvp->pv_xrmax);
158 	size_t newsize = BT_SIZEOFMAP(dtp->dt_xlatorid);
159 
160 	assert(id >= 0 && id < dtp->dt_xlatorid);
161 
162 	if (newsize > oldsize) {
163 		ulong_t *xrefs = dt_zalloc(dtp, newsize);
164 
165 		if (xrefs == NULL)
166 			return (-1);
167 
168 		bcopy(pvp->pv_xrefs, xrefs, oldsize);
169 		dt_free(dtp, pvp->pv_xrefs);
170 
171 		pvp->pv_xrefs = xrefs;
172 		pvp->pv_xrmax = dtp->dt_xlatorid;
173 	}
174 
175 	BT_SET(pvp->pv_xrefs, id);
176 	return (0);
177 }
178 
179 static uint8_t
180 dt_probe_argmap(dt_node_t *xnp, dt_node_t *nnp)
181 {
182 	uint8_t i;
183 
184 	for (i = 0; nnp != NULL; i++) {
185 		if (nnp->dn_string != NULL &&
186 		    strcmp(nnp->dn_string, xnp->dn_string) == 0)
187 			break;
188 		else
189 			nnp = nnp->dn_list;
190 	}
191 
192 	return (i);
193 }
194 
195 static dt_node_t *
196 dt_probe_alloc_args(dt_provider_t *pvp, int argc)
197 {
198 	dt_node_t *args = NULL, *pnp = NULL, *dnp;
199 	int i;
200 
201 	for (i = 0; i < argc; i++, pnp = dnp) {
202 		if ((dnp = dt_node_xalloc(pvp->pv_hdl, DT_NODE_TYPE)) == NULL)
203 			return (NULL);
204 
205 		dnp->dn_link = pvp->pv_nodes;
206 		pvp->pv_nodes = dnp;
207 
208 		if (args == NULL)
209 			args = dnp;
210 		else
211 			pnp->dn_list = dnp;
212 	}
213 
214 	return (args);
215 }
216 
217 static size_t
218 dt_probe_keylen(const dtrace_probedesc_t *pdp)
219 {
220 	return (strlen(pdp->dtpd_mod) + 1 +
221 	    strlen(pdp->dtpd_func) + 1 + strlen(pdp->dtpd_name) + 1);
222 }
223 
224 static char *
225 dt_probe_key(const dtrace_probedesc_t *pdp, char *s)
226 {
227 	(void) snprintf(s, INT_MAX, "%s:%s:%s",
228 	    pdp->dtpd_mod, pdp->dtpd_func, pdp->dtpd_name);
229 	return (s);
230 }
231 
232 /*
233  * If a probe was discovered from the kernel, ask dtrace(7D) for a description
234  * of each of its arguments, including native and translated types.
235  */
236 static dt_probe_t *
237 dt_probe_discover(dt_provider_t *pvp, const dtrace_probedesc_t *pdp)
238 {
239 	dtrace_hdl_t *dtp = pvp->pv_hdl;
240 	char *name = dt_probe_key(pdp, alloca(dt_probe_keylen(pdp)));
241 
242 	dt_node_t *xargs, *nargs;
243 	dt_ident_t *idp;
244 	dt_probe_t *prp;
245 
246 	dtrace_typeinfo_t dtt;
247 	int i, nc, xc;
248 
249 	int adc = _dtrace_argmax;
250 	dtrace_argdesc_t *adv = alloca(sizeof (dtrace_argdesc_t) * adc);
251 	dtrace_argdesc_t *adp = adv;
252 
253 	assert(strcmp(pvp->pv_desc.dtvd_name, pdp->dtpd_provider) == 0);
254 	assert(pdp->dtpd_id != DTRACE_IDNONE);
255 
256 	dt_dprintf("discovering probe %s:%s id=%d\n",
257 	    pvp->pv_desc.dtvd_name, name, pdp->dtpd_id);
258 
259 	for (nc = -1, i = 0; i < adc; i++, adp++) {
260 		bzero(adp, sizeof (dtrace_argdesc_t));
261 		adp->dtargd_ndx = i;
262 		adp->dtargd_id = pdp->dtpd_id;
263 
264 		if (dt_ioctl(dtp, DTRACEIOC_PROBEARG, adp) != 0) {
265 			(void) dt_set_errno(dtp, errno);
266 			return (NULL);
267 		}
268 
269 		if (adp->dtargd_ndx == DTRACE_ARGNONE)
270 			break; /* all argument descs have been retrieved */
271 
272 		nc = MAX(nc, adp->dtargd_mapping);
273 	}
274 
275 	xc = i;
276 	nc++;
277 
278 	/*
279 	 * The pid provider believes in giving the kernel a break. No reason to
280 	 * give the kernel all the ctf containers that we're keeping ourselves
281 	 * just to get it back from it. So if we're coming from a pid provider
282 	 * probe and the kernel gave us no argument information we'll get some
283 	 * here. If for some crazy reason the kernel knows about our userland
284 	 * types then we just ignore this.
285 	 */
286 	if (xc == 0 && nc == 0 &&
287 	    strncmp(pvp->pv_desc.dtvd_name, "pid", 3) == 0) {
288 		nc = adc;
289 		dt_pid_get_types(dtp, pdp, adv, &nc);
290 		xc = nc;
291 	}
292 
293 	/*
294 	 * Now that we have discovered the number of native and translated
295 	 * arguments from the argument descriptions, allocate a new probe ident
296 	 * and corresponding dt_probe_t and hash it into the provider.
297 	 */
298 	xargs = dt_probe_alloc_args(pvp, xc);
299 	nargs = dt_probe_alloc_args(pvp, nc);
300 
301 	if ((xc != 0 && xargs == NULL) || (nc != 0 && nargs == NULL))
302 		return (NULL); /* dt_errno is set for us */
303 
304 	idp = dt_ident_create(name, DT_IDENT_PROBE,
305 	    DT_IDFLG_ORPHAN, pdp->dtpd_id, _dtrace_defattr, 0,
306 	    &dt_idops_probe, NULL, dtp->dt_gen);
307 
308 	if (idp == NULL) {
309 		(void) dt_set_errno(dtp, EDT_NOMEM);
310 		return (NULL);
311 	}
312 
313 	if ((prp = dt_probe_create(dtp, idp, 2,
314 	    nargs, nc, xargs, xc)) == NULL) {
315 		dt_ident_destroy(idp);
316 		return (NULL);
317 	}
318 
319 	dt_probe_declare(pvp, prp);
320 
321 	/*
322 	 * Once our new dt_probe_t is fully constructed, iterate over the
323 	 * cached argument descriptions and assign types to prp->pr_nargv[]
324 	 * and prp->pr_xargv[] and assign mappings to prp->pr_mapping[].
325 	 */
326 	for (adp = adv, i = 0; i < xc; i++, adp++) {
327 		if (dtrace_type_strcompile(dtp,
328 		    adp->dtargd_native, &dtt) != 0) {
329 			dt_dprintf("failed to resolve input type %s "
330 			    "for %s:%s arg #%d: %s\n", adp->dtargd_native,
331 			    pvp->pv_desc.dtvd_name, name, i + 1,
332 			    dtrace_errmsg(dtp, dtrace_errno(dtp)));
333 
334 			dtt.dtt_object = NULL;
335 			dtt.dtt_ctfp = NULL;
336 			dtt.dtt_type = CTF_ERR;
337 		} else {
338 			dt_node_type_assign(prp->pr_nargv[adp->dtargd_mapping],
339 			    dtt.dtt_ctfp, dtt.dtt_type,
340 			    dtt.dtt_flags & DTT_FL_USER ? B_TRUE : B_FALSE);
341 		}
342 
343 		if (dtt.dtt_type != CTF_ERR && (adp->dtargd_xlate[0] == '\0' ||
344 		    strcmp(adp->dtargd_native, adp->dtargd_xlate) == 0)) {
345 			dt_node_type_propagate(prp->pr_nargv[
346 			    adp->dtargd_mapping], prp->pr_xargv[i]);
347 		} else if (dtrace_type_strcompile(dtp,
348 		    adp->dtargd_xlate, &dtt) != 0) {
349 			dt_dprintf("failed to resolve output type %s "
350 			    "for %s:%s arg #%d: %s\n", adp->dtargd_xlate,
351 			    pvp->pv_desc.dtvd_name, name, i + 1,
352 			    dtrace_errmsg(dtp, dtrace_errno(dtp)));
353 
354 			dtt.dtt_object = NULL;
355 			dtt.dtt_ctfp = NULL;
356 			dtt.dtt_type = CTF_ERR;
357 		} else {
358 			dt_node_type_assign(prp->pr_xargv[i],
359 			    dtt.dtt_ctfp, dtt.dtt_type, B_FALSE);
360 		}
361 
362 		prp->pr_mapping[i] = adp->dtargd_mapping;
363 		prp->pr_argv[i] = dtt;
364 	}
365 
366 	return (prp);
367 }
368 
369 /*
370  * Lookup a probe declaration based on a known provider and full or partially
371  * specified module, function, and name.  If the probe is not known to us yet,
372  * ask dtrace(7D) to match the description and then cache any useful results.
373  */
374 dt_probe_t *
375 dt_probe_lookup(dt_provider_t *pvp, const char *s)
376 {
377 	dtrace_hdl_t *dtp = pvp->pv_hdl;
378 	dtrace_probedesc_t pd;
379 	dt_ident_t *idp;
380 	size_t keylen;
381 	char *key;
382 
383 	if (dtrace_str2desc(dtp, DTRACE_PROBESPEC_NAME, s, &pd) != 0)
384 		return (NULL); /* dt_errno is set for us */
385 
386 	keylen = dt_probe_keylen(&pd);
387 	key = dt_probe_key(&pd, alloca(keylen));
388 
389 	/*
390 	 * If the probe is already declared, then return the dt_probe_t from
391 	 * the existing identifier.  This could come from a static declaration
392 	 * or it could have been cached from an earlier call to this function.
393 	 */
394 	if ((idp = dt_idhash_lookup(pvp->pv_probes, key)) != NULL)
395 		return (idp->di_data);
396 
397 	/*
398 	 * If the probe isn't known, use the probe description computed above
399 	 * to ask dtrace(7D) to find the first matching probe.
400 	 */
401 	if (dt_ioctl(dtp, DTRACEIOC_PROBEMATCH, &pd) == 0)
402 		return (dt_probe_discover(pvp, &pd));
403 
404 	if (errno == ESRCH || errno == EBADF)
405 		(void) dt_set_errno(dtp, EDT_NOPROBE);
406 	else
407 		(void) dt_set_errno(dtp, errno);
408 
409 	return (NULL);
410 }
411 
412 dt_probe_t *
413 dt_probe_create(dtrace_hdl_t *dtp, dt_ident_t *idp, int protoc,
414     dt_node_t *nargs, uint_t nargc, dt_node_t *xargs, uint_t xargc)
415 {
416 	dt_module_t *dmp;
417 	dt_probe_t *prp;
418 	const char *p;
419 	uint_t i;
420 
421 	assert(idp->di_kind == DT_IDENT_PROBE);
422 	assert(idp->di_data == NULL);
423 
424 	/*
425 	 * If only a single prototype is given, set xargc/s to nargc/s to
426 	 * simplify subsequent use.  Note that we can have one or both of nargs
427 	 * and xargs be specified but set to NULL, indicating a void prototype.
428 	 */
429 	if (protoc < 2) {
430 		assert(xargs == NULL);
431 		assert(xargc == 0);
432 		xargs = nargs;
433 		xargc = nargc;
434 	}
435 
436 	if ((prp = dt_alloc(dtp, sizeof (dt_probe_t))) == NULL)
437 		return (NULL);
438 
439 	prp->pr_pvp = NULL;
440 	prp->pr_ident = idp;
441 
442 	p = strrchr(idp->di_name, ':');
443 	assert(p != NULL);
444 	prp->pr_name = p + 1;
445 
446 	prp->pr_nargs = nargs;
447 	prp->pr_nargv = dt_alloc(dtp, sizeof (dt_node_t *) * nargc);
448 	prp->pr_nargc = nargc;
449 	prp->pr_xargs = xargs;
450 	prp->pr_xargv = dt_alloc(dtp, sizeof (dt_node_t *) * xargc);
451 	prp->pr_xargc = xargc;
452 	prp->pr_mapping = dt_alloc(dtp, sizeof (uint8_t) * xargc);
453 	prp->pr_inst = NULL;
454 	prp->pr_argv = dt_alloc(dtp, sizeof (dtrace_typeinfo_t) * xargc);
455 	prp->pr_argc = xargc;
456 
457 	if ((prp->pr_nargc != 0 && prp->pr_nargv == NULL) ||
458 	    (prp->pr_xargc != 0 && prp->pr_xargv == NULL) ||
459 	    (prp->pr_xargc != 0 && prp->pr_mapping == NULL) ||
460 	    (prp->pr_argc != 0 && prp->pr_argv == NULL)) {
461 		dt_probe_destroy(prp);
462 		return (NULL);
463 	}
464 
465 	for (i = 0; i < xargc; i++, xargs = xargs->dn_list) {
466 		if (xargs->dn_string != NULL)
467 			prp->pr_mapping[i] = dt_probe_argmap(xargs, nargs);
468 		else
469 			prp->pr_mapping[i] = i;
470 
471 		prp->pr_xargv[i] = xargs;
472 
473 		if ((dmp = dt_module_lookup_by_ctf(dtp,
474 		    xargs->dn_ctfp)) != NULL)
475 			prp->pr_argv[i].dtt_object = dmp->dm_name;
476 		else
477 			prp->pr_argv[i].dtt_object = NULL;
478 
479 		prp->pr_argv[i].dtt_ctfp = xargs->dn_ctfp;
480 		prp->pr_argv[i].dtt_type = xargs->dn_type;
481 	}
482 
483 	for (i = 0; i < nargc; i++, nargs = nargs->dn_list)
484 		prp->pr_nargv[i] = nargs;
485 
486 	idp->di_data = prp;
487 	return (prp);
488 }
489 
490 void
491 dt_probe_declare(dt_provider_t *pvp, dt_probe_t *prp)
492 {
493 	assert(prp->pr_ident->di_kind == DT_IDENT_PROBE);
494 	assert(prp->pr_ident->di_data == prp);
495 	assert(prp->pr_pvp == NULL);
496 
497 	if (prp->pr_xargs != prp->pr_nargs)
498 		pvp->pv_flags &= ~DT_PROVIDER_INTF;
499 
500 	prp->pr_pvp = pvp;
501 	dt_idhash_xinsert(pvp->pv_probes, prp->pr_ident);
502 }
503 
504 void
505 dt_probe_destroy(dt_probe_t *prp)
506 {
507 	dt_probe_instance_t *pip, *pip_next;
508 	dtrace_hdl_t *dtp;
509 
510 	if (prp->pr_pvp != NULL)
511 		dtp = prp->pr_pvp->pv_hdl;
512 	else
513 		dtp = yypcb->pcb_hdl;
514 
515 	dt_node_list_free(&prp->pr_nargs);
516 	dt_node_list_free(&prp->pr_xargs);
517 
518 	dt_free(dtp, prp->pr_nargv);
519 	dt_free(dtp, prp->pr_xargv);
520 
521 	for (pip = prp->pr_inst; pip != NULL; pip = pip_next) {
522 		pip_next = pip->pi_next;
523 		dt_free(dtp, pip->pi_rname);
524 		dt_free(dtp, pip->pi_fname);
525 		dt_free(dtp, pip->pi_offs);
526 		dt_free(dtp, pip->pi_enoffs);
527 		dt_free(dtp, pip);
528 	}
529 
530 	dt_free(dtp, prp->pr_mapping);
531 	dt_free(dtp, prp->pr_argv);
532 	dt_free(dtp, prp);
533 }
534 
535 int
536 dt_probe_define(dt_provider_t *pvp, dt_probe_t *prp,
537     const char *fname, const char *rname, uint32_t offset, int isenabled)
538 {
539 	dtrace_hdl_t *dtp = pvp->pv_hdl;
540 	dt_probe_instance_t *pip;
541 	uint32_t **offs;
542 	uint_t *noffs, *maxoffs;
543 
544 	assert(fname != NULL);
545 
546 	for (pip = prp->pr_inst; pip != NULL; pip = pip->pi_next) {
547 		if (strcmp(pip->pi_fname, fname) == 0 &&
548 		    strcmp(pip->pi_rname, rname) == 0)
549 			break;
550 	}
551 
552 	if (pip == NULL) {
553 		if ((pip = dt_zalloc(dtp, sizeof (*pip))) == NULL)
554 			return (-1);
555 
556 		if ((pip->pi_offs = dt_zalloc(dtp, sizeof (uint32_t))) == NULL)
557 			goto nomem;
558 
559 		if ((pip->pi_enoffs = dt_zalloc(dtp,
560 		    sizeof (uint32_t))) == NULL)
561 			goto nomem;
562 
563 		if ((pip->pi_fname = strdup(fname)) == NULL)
564 			goto nomem;
565 
566 		if ((pip->pi_rname = strdup(rname)) == NULL)
567 			goto nomem;
568 
569 		pip->pi_noffs = 0;
570 		pip->pi_maxoffs = 1;
571 		pip->pi_nenoffs = 0;
572 		pip->pi_maxenoffs = 1;
573 
574 		pip->pi_next = prp->pr_inst;
575 
576 		prp->pr_inst = pip;
577 	}
578 
579 	if (isenabled) {
580 		offs = &pip->pi_enoffs;
581 		noffs = &pip->pi_nenoffs;
582 		maxoffs = &pip->pi_maxenoffs;
583 	} else {
584 		offs = &pip->pi_offs;
585 		noffs = &pip->pi_noffs;
586 		maxoffs = &pip->pi_maxoffs;
587 	}
588 
589 	if (*noffs == *maxoffs) {
590 		uint_t new_max = *maxoffs * 2;
591 		uint32_t *new_offs = dt_alloc(dtp, sizeof (uint32_t) * new_max);
592 
593 		if (new_offs == NULL)
594 			return (-1);
595 
596 		bcopy(*offs, new_offs, sizeof (uint32_t) * *maxoffs);
597 
598 		dt_free(dtp, *offs);
599 		*maxoffs = new_max;
600 		*offs = new_offs;
601 	}
602 
603 	dt_dprintf("defined probe %s %s:%s %s() +0x%x (%s)\n",
604 	    isenabled ? "(is-enabled)" : "",
605 	    pvp->pv_desc.dtvd_name, prp->pr_ident->di_name, fname, offset,
606 	    rname);
607 
608 	assert(*noffs < *maxoffs);
609 	(*offs)[(*noffs)++] = offset;
610 
611 	return (0);
612 
613 nomem:
614 	dt_free(dtp, pip->pi_fname);
615 	dt_free(dtp, pip->pi_enoffs);
616 	dt_free(dtp, pip->pi_offs);
617 	dt_free(dtp, pip);
618 	return (dt_set_errno(dtp, EDT_NOMEM));
619 }
620 
621 /*
622  * Lookup the dynamic translator type tag for the specified probe argument and
623  * assign the type to the specified node.  If the type is not yet defined, add
624  * it to the "D" module's type container as a typedef for an unknown type.
625  */
626 dt_node_t *
627 dt_probe_tag(dt_probe_t *prp, uint_t argn, dt_node_t *dnp)
628 {
629 	dtrace_hdl_t *dtp = prp->pr_pvp->pv_hdl;
630 	dtrace_typeinfo_t dtt;
631 	size_t len;
632 	char *tag;
633 
634 	len = snprintf(NULL, 0, "__dtrace_%s___%s_arg%u",
635 	    prp->pr_pvp->pv_desc.dtvd_name, prp->pr_name, argn);
636 
637 	tag = alloca(len + 1);
638 
639 	(void) snprintf(tag, len + 1, "__dtrace_%s___%s_arg%u",
640 	    prp->pr_pvp->pv_desc.dtvd_name, prp->pr_name, argn);
641 
642 	if (dtrace_lookup_by_type(dtp, DTRACE_OBJ_DDEFS, tag, &dtt) != 0) {
643 		dtt.dtt_object = DTRACE_OBJ_DDEFS;
644 		dtt.dtt_ctfp = DT_DYN_CTFP(dtp);
645 		dtt.dtt_type = ctf_add_typedef(DT_DYN_CTFP(dtp),
646 		    CTF_ADD_ROOT, tag, DT_DYN_TYPE(dtp));
647 
648 		if (dtt.dtt_type == CTF_ERR ||
649 		    ctf_update(dtt.dtt_ctfp) == CTF_ERR) {
650 			xyerror(D_UNKNOWN, "cannot define type %s: %s\n",
651 			    tag, ctf_errmsg(ctf_errno(dtt.dtt_ctfp)));
652 		}
653 	}
654 
655 	bzero(dnp, sizeof (dt_node_t));
656 	dnp->dn_kind = DT_NODE_TYPE;
657 
658 	dt_node_type_assign(dnp, dtt.dtt_ctfp, dtt.dtt_type, B_FALSE);
659 	dt_node_attr_assign(dnp, _dtrace_defattr);
660 
661 	return (dnp);
662 }
663 
664 /*ARGSUSED*/
665 static int
666 dt_probe_desc(dtrace_hdl_t *dtp, const dtrace_probedesc_t *pdp, void *arg)
667 {
668 	if (((dtrace_probedesc_t *)arg)->dtpd_id == DTRACE_IDNONE) {
669 		bcopy(pdp, arg, sizeof (dtrace_probedesc_t));
670 		return (0);
671 	}
672 
673 	return (1);
674 }
675 
676 dt_probe_t *
677 dt_probe_info(dtrace_hdl_t *dtp,
678     const dtrace_probedesc_t *pdp, dtrace_probeinfo_t *pip)
679 {
680 	int m_is_glob = pdp->dtpd_mod[0] == '\0' || strisglob(pdp->dtpd_mod);
681 	int f_is_glob = pdp->dtpd_func[0] == '\0' || strisglob(pdp->dtpd_func);
682 	int n_is_glob = pdp->dtpd_name[0] == '\0' || strisglob(pdp->dtpd_name);
683 
684 	dt_probe_t *prp = NULL;
685 	const dtrace_pattr_t *pap;
686 	dt_provider_t *pvp;
687 	dt_ident_t *idp;
688 
689 	/*
690 	 * Attempt to lookup the probe in our existing cache for this provider.
691 	 * If none is found and an explicit probe ID was specified, discover
692 	 * that specific probe and cache its description and arguments.
693 	 */
694 	if ((pvp = dt_provider_lookup(dtp, pdp->dtpd_provider)) != NULL) {
695 		size_t keylen = dt_probe_keylen(pdp);
696 		char *key = dt_probe_key(pdp, alloca(keylen));
697 
698 		if ((idp = dt_idhash_lookup(pvp->pv_probes, key)) != NULL)
699 			prp = idp->di_data;
700 		else if (pdp->dtpd_id != DTRACE_IDNONE)
701 			prp = dt_probe_discover(pvp, pdp);
702 	}
703 
704 	/*
705 	 * If no probe was found in our cache, convert the caller's partial
706 	 * probe description into a fully-formed matching probe description by
707 	 * iterating over up to at most two probes that match 'pdp'.  We then
708 	 * call dt_probe_discover() on the resulting probe identifier.
709 	 */
710 	if (prp == NULL) {
711 		dtrace_probedesc_t pd;
712 		int m;
713 
714 		bzero(&pd, sizeof (pd));
715 		pd.dtpd_id = DTRACE_IDNONE;
716 
717 		/*
718 		 * Call dtrace_probe_iter() to find matching probes.  Our
719 		 * dt_probe_desc() callback will produce the following results:
720 		 *
721 		 * m < 0 dtrace_probe_iter() found zero matches (or failed).
722 		 * m > 0 dtrace_probe_iter() found more than one match.
723 		 * m = 0 dtrace_probe_iter() found exactly one match.
724 		 */
725 		if ((m = dtrace_probe_iter(dtp, pdp, dt_probe_desc, &pd)) < 0)
726 			return (NULL); /* dt_errno is set for us */
727 
728 		if ((pvp = dt_provider_lookup(dtp, pd.dtpd_provider)) == NULL)
729 			return (NULL); /* dt_errno is set for us */
730 
731 		/*
732 		 * If more than one probe was matched, then do not report probe
733 		 * information if either of the following conditions is true:
734 		 *
735 		 * (a) The Arguments Data stability of the matched provider is
736 		 *	less than Evolving.
737 		 *
738 		 * (b) Any description component that is at least Evolving is
739 		 *	empty or is specified using a globbing expression.
740 		 *
741 		 * These conditions imply that providers that provide Evolving
742 		 * or better Arguments Data stability must guarantee that all
743 		 * probes with identical field names in a field of Evolving or
744 		 * better Name stability have identical argument signatures.
745 		 */
746 		if (m > 0) {
747 			if (pvp->pv_desc.dtvd_attr.dtpa_args.dtat_data <
748 			    DTRACE_STABILITY_EVOLVING) {
749 				(void) dt_set_errno(dtp, EDT_UNSTABLE);
750 				return (NULL);
751 			}
752 
753 
754 			if (pvp->pv_desc.dtvd_attr.dtpa_mod.dtat_name >=
755 			    DTRACE_STABILITY_EVOLVING && m_is_glob) {
756 				(void) dt_set_errno(dtp, EDT_UNSTABLE);
757 				return (NULL);
758 			}
759 
760 			if (pvp->pv_desc.dtvd_attr.dtpa_func.dtat_name >=
761 			    DTRACE_STABILITY_EVOLVING && f_is_glob) {
762 				(void) dt_set_errno(dtp, EDT_UNSTABLE);
763 				return (NULL);
764 			}
765 
766 			if (pvp->pv_desc.dtvd_attr.dtpa_name.dtat_name >=
767 			    DTRACE_STABILITY_EVOLVING && n_is_glob) {
768 				(void) dt_set_errno(dtp, EDT_UNSTABLE);
769 				return (NULL);
770 			}
771 		}
772 
773 		/*
774 		 * If we matched a probe exported by dtrace(7D), then discover
775 		 * the real attributes.  Otherwise grab the static declaration.
776 		 */
777 		if (pd.dtpd_id != DTRACE_IDNONE)
778 			prp = dt_probe_discover(pvp, &pd);
779 		else
780 			prp = dt_probe_lookup(pvp, pd.dtpd_name);
781 
782 		if (prp == NULL)
783 			return (NULL); /* dt_errno is set for us */
784 	}
785 
786 	assert(pvp != NULL && prp != NULL);
787 
788 	/*
789 	 * Compute the probe description attributes by taking the minimum of
790 	 * the attributes of the specified fields.  If no provider is specified
791 	 * or a glob pattern is used for the provider, use Unstable attributes.
792 	 */
793 	if (pdp->dtpd_provider[0] == '\0' || strisglob(pdp->dtpd_provider))
794 		pap = &_dtrace_prvdesc;
795 	else
796 		pap = &pvp->pv_desc.dtvd_attr;
797 
798 	pip->dtp_attr = pap->dtpa_provider;
799 
800 	if (!m_is_glob)
801 		pip->dtp_attr = dt_attr_min(pip->dtp_attr, pap->dtpa_mod);
802 	if (!f_is_glob)
803 		pip->dtp_attr = dt_attr_min(pip->dtp_attr, pap->dtpa_func);
804 	if (!n_is_glob)
805 		pip->dtp_attr = dt_attr_min(pip->dtp_attr, pap->dtpa_name);
806 
807 	pip->dtp_arga = pap->dtpa_args;
808 	pip->dtp_argv = prp->pr_argv;
809 	pip->dtp_argc = prp->pr_argc;
810 
811 	return (prp);
812 }
813 
814 int
815 dtrace_probe_info(dtrace_hdl_t *dtp,
816     const dtrace_probedesc_t *pdp, dtrace_probeinfo_t *pip)
817 {
818 	return (dt_probe_info(dtp, pdp, pip) != NULL ? 0 : -1);
819 }
820 
821 /*ARGSUSED*/
822 static int
823 dt_probe_iter(dt_idhash_t *ihp, dt_ident_t *idp, dt_probe_iter_t *pit)
824 {
825 	const dt_probe_t *prp = idp->di_data;
826 
827 	if (!dt_gmatch(prp->pr_name, pit->pit_pat))
828 		return (0); /* continue on and examine next probe in hash */
829 
830 	(void) strlcpy(pit->pit_desc.dtpd_name, prp->pr_name, DTRACE_NAMELEN);
831 	pit->pit_desc.dtpd_id = idp->di_id;
832 	pit->pit_matches++;
833 
834 	return (pit->pit_func(pit->pit_hdl, &pit->pit_desc, pit->pit_arg));
835 }
836 
837 int
838 dtrace_probe_iter(dtrace_hdl_t *dtp,
839     const dtrace_probedesc_t *pdp, dtrace_probe_f *func, void *arg)
840 {
841 	const char *provider = pdp ? pdp->dtpd_provider : NULL;
842 	dtrace_id_t id = DTRACE_IDNONE;
843 
844 	dtrace_probedesc_t pd;
845 	dt_probe_iter_t pit;
846 	int cmd, rv;
847 
848 	bzero(&pit, sizeof (pit));
849 	pit.pit_hdl = dtp;
850 	pit.pit_func = func;
851 	pit.pit_arg = arg;
852 	pit.pit_pat = pdp ? pdp->dtpd_name : NULL;
853 
854 	for (pit.pit_pvp = dt_list_next(&dtp->dt_provlist);
855 	    pit.pit_pvp != NULL; pit.pit_pvp = dt_list_next(pit.pit_pvp)) {
856 
857 		if (pit.pit_pvp->pv_flags & DT_PROVIDER_IMPL)
858 			continue; /* we'll get these later using dt_ioctl() */
859 
860 		if (!dt_gmatch(pit.pit_pvp->pv_desc.dtvd_name, provider))
861 			continue;
862 
863 		(void) strlcpy(pit.pit_desc.dtpd_provider,
864 		    pit.pit_pvp->pv_desc.dtvd_name, DTRACE_PROVNAMELEN);
865 
866 		if ((rv = dt_idhash_iter(pit.pit_pvp->pv_probes,
867 		    (dt_idhash_f *)dt_probe_iter, &pit)) != 0)
868 			return (rv);
869 	}
870 
871 	if (pdp != NULL)
872 		cmd = DTRACEIOC_PROBEMATCH;
873 	else
874 		cmd = DTRACEIOC_PROBES;
875 
876 	for (;;) {
877 		if (pdp != NULL)
878 			bcopy(pdp, &pd, sizeof (pd));
879 
880 		pd.dtpd_id = id;
881 
882 		if (dt_ioctl(dtp, cmd, &pd) != 0)
883 			break;
884 		else if ((rv = func(dtp, &pd, arg)) != 0)
885 			return (rv);
886 
887 		pit.pit_matches++;
888 		id = pd.dtpd_id + 1;
889 	}
890 
891 	switch (errno) {
892 	case ESRCH:
893 	case EBADF:
894 		return (pit.pit_matches ? 0 : dt_set_errno(dtp, EDT_NOPROBE));
895 	case EINVAL:
896 		return (dt_set_errno(dtp, EDT_BADPGLOB));
897 	default:
898 		return (dt_set_errno(dtp, errno));
899 	}
900 }
901