xref: /illumos-gate/usr/src/cmd/mdb/common/mdb/mdb_nv.c (revision cd9ea253fe43247db7ca9d20404804e8f2926e21)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 /*
27  * Copyright (c) 2013 Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
28  * Copyright 2024 Oxide Computer Company
29  */
30 
31 #include <mdb/mdb_debug.h>
32 #include <mdb/mdb_string.h>
33 #include <mdb/mdb_modapi.h>
34 #include <mdb/mdb_err.h>
35 #include <mdb/mdb_nv.h>
36 #include <mdb/mdb.h>
37 
38 #define	NV_NAME(v) \
39 	(((v)->v_flags & MDB_NV_EXTNAME) ? (v)->v_ename : (v)->v_lname)
40 
41 #define	NV_SIZE(v) \
42 	(((v)->v_flags & MDB_NV_EXTNAME) ? sizeof (mdb_var_t) : \
43 	sizeof (mdb_var_t) + strlen((v)->v_lname))
44 
45 #define	NV_HASHSZ	211
46 
47 static size_t
nv_hashstring(const char * key)48 nv_hashstring(const char *key)
49 {
50 	size_t g, h = 0;
51 	const char *p;
52 
53 	ASSERT(key != NULL);
54 
55 	for (p = key; *p != '\0'; p++) {
56 		h = (h << 4) + *p;
57 
58 		if ((g = (h & 0xf0000000)) != 0) {
59 			h ^= (g >> 24);
60 			h ^= g;
61 		}
62 	}
63 
64 	return (h);
65 }
66 
67 static mdb_var_t *
nv_var_alloc(const char * name,const mdb_nv_disc_t * disc,uintmax_t value,uint_t flags,uint_t um_flags,mdb_var_t * next)68 nv_var_alloc(const char *name, const mdb_nv_disc_t *disc,
69     uintmax_t value, uint_t flags, uint_t um_flags, mdb_var_t *next)
70 {
71 	size_t nbytes;
72 	mdb_var_t *v;
73 
74 	if (flags & MDB_NV_EXTNAME)
75 		nbytes = sizeof (mdb_var_t);
76 	else
77 		nbytes = sizeof (mdb_var_t) + strlen(name);
78 
79 	v = mdb_alloc(nbytes, um_flags);
80 
81 	if (v == NULL)
82 		return (NULL);
83 
84 	if (flags & MDB_NV_EXTNAME) {
85 		v->v_ename = name;
86 		v->v_lname[0] = '\0';
87 	} else {
88 		/*
89 		 * We don't overflow here since the mdb_var_t itself has
90 		 * room for the trailing \0.
91 		 */
92 		(void) strcpy(v->v_lname, name);
93 		v->v_ename = NULL;
94 	}
95 
96 	v->v_uvalue = value;
97 	v->v_flags = flags & ~(MDB_NV_SILENT | MDB_NV_INTERPOS);
98 	v->v_disc = disc;
99 	v->v_next = next;
100 
101 	return (v);
102 }
103 
104 static void
nv_var_free(mdb_var_t * v,uint_t um_flags)105 nv_var_free(mdb_var_t *v, uint_t um_flags)
106 {
107 	if (um_flags & UM_GC)
108 		return;
109 
110 	if (v->v_flags & MDB_NV_OVERLOAD) {
111 		mdb_var_t *w, *nw;
112 
113 		for (w = v->v_ndef; w != NULL; w = nw) {
114 			nw = w->v_ndef;
115 			mdb_free(w, NV_SIZE(w));
116 		}
117 	}
118 
119 	mdb_free(v, NV_SIZE(v));
120 }
121 
122 /*
123  * Can return NULL only if the nv's memory allocation flags include UM_NOSLEEP
124  */
125 mdb_nv_t *
mdb_nv_create(mdb_nv_t * nv,uint_t um_flags)126 mdb_nv_create(mdb_nv_t *nv, uint_t um_flags)
127 {
128 	nv->nv_hash = mdb_zalloc(sizeof (mdb_var_t *) * NV_HASHSZ, um_flags);
129 
130 	if (nv->nv_hash == NULL)
131 		return (NULL);
132 
133 	nv->nv_hashsz = NV_HASHSZ;
134 	nv->nv_nelems = 0;
135 	nv->nv_iter_elt = NULL;
136 	nv->nv_iter_bucket = 0;
137 	nv->nv_um_flags = um_flags;
138 
139 	return (nv);
140 }
141 
142 void
mdb_nv_destroy(mdb_nv_t * nv)143 mdb_nv_destroy(mdb_nv_t *nv)
144 {
145 	mdb_var_t *v, *w;
146 	size_t i;
147 
148 	if (nv->nv_um_flags & UM_GC)
149 		return;
150 
151 	for (i = 0; i < nv->nv_hashsz; i++) {
152 		for (v = nv->nv_hash[i]; v != NULL; v = w) {
153 			w = v->v_next;
154 			nv_var_free(v, nv->nv_um_flags);
155 		}
156 	}
157 
158 	mdb_free(nv->nv_hash, sizeof (mdb_var_t *) * nv->nv_hashsz);
159 }
160 
161 mdb_var_t *
mdb_nv_lookup(mdb_nv_t * nv,const char * name)162 mdb_nv_lookup(mdb_nv_t *nv, const char *name)
163 {
164 	size_t i = nv_hashstring(name) % nv->nv_hashsz;
165 	mdb_var_t *v;
166 
167 	for (v = nv->nv_hash[i]; v != NULL; v = v->v_next) {
168 		if (strcmp(NV_NAME(v), name) == 0)
169 			return (v);
170 	}
171 
172 	return (NULL);
173 }
174 
175 /*
176  * Interpose W in place of V.  We replace V with W in nv_hash, and then
177  * set W's v_ndef overload chain to point at V.
178  */
179 static mdb_var_t *
nv_var_interpos(mdb_nv_t * nv,size_t i,mdb_var_t * v,mdb_var_t * w)180 nv_var_interpos(mdb_nv_t *nv, size_t i, mdb_var_t *v, mdb_var_t *w)
181 {
182 	mdb_var_t **pvp = &nv->nv_hash[i];
183 
184 	while (*pvp != v) {
185 		mdb_var_t *vp = *pvp;
186 		ASSERT(vp != NULL);
187 		pvp = &vp->v_next;
188 	}
189 
190 	*pvp = w;
191 	w->v_next = v->v_next;
192 	w->v_ndef = v;
193 	v->v_next = NULL;
194 
195 	return (w);
196 }
197 
198 /*
199  * Add W to the end of V's overload chain.  We simply follow v_ndef to the
200  * end, and then append W.  We don't expect these chains to grow very long.
201  */
202 static mdb_var_t *
nv_var_overload(mdb_var_t * v,mdb_var_t * w)203 nv_var_overload(mdb_var_t *v, mdb_var_t *w)
204 {
205 	while (v->v_ndef != NULL)
206 		v = v->v_ndef;
207 
208 	v->v_ndef = w;
209 	return (w);
210 }
211 
212 static void
nv_resize(mdb_nv_t * nv)213 nv_resize(mdb_nv_t *nv)
214 {
215 	size_t i, bucket, new_hashsz = (nv->nv_hashsz << 1) - 1;
216 	mdb_var_t *v, *w, **new_hash =
217 	    mdb_zalloc(sizeof (mdb_var_t *) * new_hashsz, nv->nv_um_flags);
218 
219 	if (new_hash == NULL) {
220 		/*
221 		 * If this fails (possible only if UM_NOSLEEP was set in our
222 		 * flags), we will simply return -- and will presumably attempt
223 		 * to rehash again on a subsequent insert.
224 		 */
225 		ASSERT(nv->nv_um_flags & UM_NOSLEEP);
226 		return;
227 	}
228 
229 	/*
230 	 * This is a point of no return:  we are going to iterate over our
231 	 * hash table, rehashing everything.  Note that the ordering within
232 	 * hash chains is not preserved:  if every element of a bucket were
233 	 * to rehash to the same bucket in the larger table, the ordering
234 	 * will be flipped.
235 	 */
236 	for (i = 0; i < nv->nv_hashsz; i++) {
237 		for (v = nv->nv_hash[i]; v != NULL; v = w) {
238 			w = v->v_next;
239 
240 			bucket = nv_hashstring(NV_NAME(v)) % new_hashsz;
241 			v->v_next = new_hash[bucket];
242 			new_hash[bucket] = v;
243 		}
244 	}
245 
246 	/*
247 	 * Everything has been rehashed; free our old hash table and point
248 	 * ourselves to the new one.
249 	 */
250 	if (!(nv->nv_um_flags & UM_GC))
251 		mdb_free(nv->nv_hash, sizeof (mdb_var_t *) * nv->nv_hashsz);
252 	nv->nv_hash = new_hash;
253 	nv->nv_hashsz = new_hashsz;
254 }
255 
256 /*
257  * Can return NULL only if the nv's memory allocation flags include UM_NOSLEEP
258  */
259 mdb_var_t *
mdb_nv_insert(mdb_nv_t * nv,const char * name,const mdb_nv_disc_t * disc,uintmax_t value,uint_t flags)260 mdb_nv_insert(mdb_nv_t *nv, const char *name, const mdb_nv_disc_t *disc,
261     uintmax_t value, uint_t flags)
262 {
263 	size_t i;
264 	mdb_var_t *v;
265 
266 	ASSERT(!(flags & MDB_NV_EXTNAME) || !(flags & MDB_NV_OVERLOAD));
267 	ASSERT(!(flags & MDB_NV_RDONLY) || !(flags & MDB_NV_OVERLOAD));
268 
269 	if (nv->nv_nelems > nv->nv_hashsz && nv->nv_iter_elt == NULL) {
270 		nv_resize(nv);
271 	}
272 
273 	i = nv_hashstring(name) % nv->nv_hashsz;
274 
275 	/*
276 	 * If the specified name is already hashed,
277 	 * and MDB_NV_OVERLOAD is set:	insert new var into overload chain
278 	 * and MDB_NV_RDONLY is set:	leave var unchanged, issue warning
279 	 * otherwise:			update var with new value
280 	 */
281 	for (v = nv->nv_hash[i]; v != NULL; v = v->v_next) {
282 		if (strcmp(NV_NAME(v), name) == 0) {
283 			if (v->v_flags & MDB_NV_OVERLOAD) {
284 				mdb_var_t *w = nv_var_alloc(NV_NAME(v), disc,
285 				    value, flags, nv->nv_um_flags, NULL);
286 
287 				if (w == NULL) {
288 					ASSERT(nv->nv_um_flags & UM_NOSLEEP);
289 					return (NULL);
290 				}
291 
292 				if (flags & MDB_NV_INTERPOS)
293 					v = nv_var_interpos(nv, i, v, w);
294 				else
295 					v = nv_var_overload(v, w);
296 
297 			} else if (v->v_flags & MDB_NV_RDONLY) {
298 				if (!(flags & MDB_NV_SILENT)) {
299 					warn("cannot modify read-only "
300 					    "variable '%s'\n", NV_NAME(v));
301 				}
302 			} else
303 				v->v_uvalue = value;
304 
305 			ASSERT(v != NULL);
306 			return (v);
307 		}
308 	}
309 
310 	/*
311 	 * If the specified name was not found, initialize a new element
312 	 * and add it to the hash table at the beginning of this chain:
313 	 */
314 	v = nv_var_alloc(name, disc, value, flags, nv->nv_um_flags,
315 	    nv->nv_hash[i]);
316 
317 	if (v == NULL) {
318 		ASSERT(nv->nv_um_flags & UM_NOSLEEP);
319 		return (NULL);
320 	}
321 
322 	nv->nv_hash[i] = v;
323 	nv->nv_nelems++;
324 
325 	return (v);
326 }
327 
328 static void
nv_var_defn_remove(mdb_var_t * v,mdb_var_t * corpse,uint_t um_flags)329 nv_var_defn_remove(mdb_var_t *v, mdb_var_t *corpse, uint_t um_flags)
330 {
331 	mdb_var_t *w = v;
332 
333 	while (v->v_ndef != NULL && v->v_ndef != corpse)
334 		v = v->v_ndef;
335 
336 	if (v == NULL) {
337 		fail("var %p ('%s') not found on defn chain of %p\n",
338 		    (void *)corpse, NV_NAME(corpse), (void *)w);
339 	}
340 
341 	v->v_ndef = corpse->v_ndef;
342 	corpse->v_ndef = NULL;
343 	nv_var_free(corpse, um_flags);
344 }
345 
346 void
mdb_nv_remove(mdb_nv_t * nv,mdb_var_t * corpse)347 mdb_nv_remove(mdb_nv_t *nv, mdb_var_t *corpse)
348 {
349 	const char *cname = NV_NAME(corpse);
350 	size_t i = nv_hashstring(cname) % nv->nv_hashsz;
351 	mdb_var_t *v = nv->nv_hash[i];
352 	mdb_var_t **pvp;
353 
354 	if (corpse->v_flags & MDB_NV_PERSIST) {
355 		warn("cannot remove persistent variable '%s'\n", cname);
356 		return;
357 	}
358 
359 	if (v != corpse) {
360 		do {
361 			if (strcmp(NV_NAME(v), cname) == 0) {
362 				if (corpse->v_flags & MDB_NV_OVERLOAD) {
363 					nv_var_defn_remove(v, corpse,
364 					    nv->nv_um_flags);
365 					return; /* No v_next changes needed */
366 				} else
367 					goto notfound;
368 			}
369 
370 			if (v->v_next == corpse)
371 				break; /* Corpse is next on the chain */
372 
373 		} while ((v = v->v_next) != NULL);
374 
375 		if (v == NULL)
376 			goto notfound;
377 
378 		pvp = &v->v_next;
379 	} else
380 		pvp = &nv->nv_hash[i];
381 
382 	if ((corpse->v_flags & MDB_NV_OVERLOAD) && corpse->v_ndef != NULL) {
383 		corpse->v_ndef->v_next = corpse->v_next;
384 		*pvp = corpse->v_ndef;
385 		corpse->v_ndef = NULL;
386 	} else {
387 		*pvp = corpse->v_next;
388 		nv->nv_nelems--;
389 	}
390 
391 	nv_var_free(corpse, nv->nv_um_flags);
392 	return;
393 
394 notfound:
395 	fail("var %p ('%s') not found on hash chain: nv=%p [%lu]\n",
396 	    (void *)corpse, cname, (void *)nv, (ulong_t)i);
397 }
398 
399 void
mdb_nv_rewind(mdb_nv_t * nv)400 mdb_nv_rewind(mdb_nv_t *nv)
401 {
402 	size_t i;
403 
404 	for (i = 0; i < nv->nv_hashsz; i++) {
405 		if (nv->nv_hash[i] != NULL)
406 			break;
407 	}
408 
409 	nv->nv_iter_elt = i < nv->nv_hashsz ? nv->nv_hash[i] : NULL;
410 	nv->nv_iter_bucket = i;
411 }
412 
413 mdb_var_t *
mdb_nv_advance(mdb_nv_t * nv)414 mdb_nv_advance(mdb_nv_t *nv)
415 {
416 	mdb_var_t *v = nv->nv_iter_elt;
417 	size_t i;
418 
419 	if (v == NULL)
420 		return (NULL);
421 
422 	if (v->v_next != NULL) {
423 		nv->nv_iter_elt = v->v_next;
424 		return (v);
425 	}
426 
427 	for (i = nv->nv_iter_bucket + 1; i < nv->nv_hashsz; i++) {
428 		if (nv->nv_hash[i] != NULL)
429 			break;
430 	}
431 
432 	nv->nv_iter_elt = i < nv->nv_hashsz ? nv->nv_hash[i] : NULL;
433 	nv->nv_iter_bucket = i;
434 
435 	return (v);
436 }
437 
438 mdb_var_t *
mdb_nv_peek(mdb_nv_t * nv)439 mdb_nv_peek(mdb_nv_t *nv)
440 {
441 	return (nv->nv_iter_elt);
442 }
443 
444 size_t
mdb_nv_size(mdb_nv_t * nv)445 mdb_nv_size(mdb_nv_t *nv)
446 {
447 	return (nv->nv_nelems);
448 }
449 
450 static int
nv_compare(const mdb_var_t ** lp,const mdb_var_t ** rp)451 nv_compare(const mdb_var_t **lp, const mdb_var_t **rp)
452 {
453 	return (strcmp(mdb_nv_get_name(*lp), mdb_nv_get_name(*rp)));
454 }
455 
456 void
mdb_nv_sort_iter(mdb_nv_t * nv,int (* func)(mdb_var_t *,void *),void * private,uint_t um_flags)457 mdb_nv_sort_iter(mdb_nv_t *nv, int (*func)(mdb_var_t *, void *),
458     void *private, uint_t um_flags)
459 {
460 	mdb_var_t **vps =
461 	    mdb_alloc(nv->nv_nelems * sizeof (mdb_var_t *), um_flags);
462 
463 	if (nv->nv_nelems != 0 && vps != NULL) {
464 		mdb_var_t *v, **vpp = vps;
465 		size_t i;
466 
467 		for (mdb_nv_rewind(nv); (v = mdb_nv_advance(nv)) != NULL; )
468 			*vpp++ = v;
469 
470 		qsort(vps, nv->nv_nelems, sizeof (mdb_var_t *),
471 		    (int (*)(const void *, const void *))nv_compare);
472 
473 		for (vpp = vps, i = 0; i < nv->nv_nelems; i++) {
474 			if (func(*vpp++, private) == -1)
475 				break;
476 		}
477 
478 		if (!(um_flags & UM_GC))
479 			mdb_free(vps, nv->nv_nelems * sizeof (mdb_var_t *));
480 	}
481 }
482 
483 void
mdb_nv_defn_iter(mdb_var_t * v,int (* func)(mdb_var_t *,void *),void * private)484 mdb_nv_defn_iter(mdb_var_t *v, int (*func)(mdb_var_t *, void *), void *private)
485 {
486 	if (func(v, private) == -1 || !(v->v_flags & MDB_NV_OVERLOAD))
487 		return;
488 
489 	for (v = v->v_ndef; v != NULL; v = v->v_ndef) {
490 		if (func(v, private) == -1)
491 			break;
492 	}
493 }
494 
495 uintmax_t
mdb_nv_get_value(const mdb_var_t * v)496 mdb_nv_get_value(const mdb_var_t *v)
497 {
498 	if (v->v_disc)
499 		return (v->v_disc->disc_get(v));
500 
501 	return (v->v_uvalue);
502 }
503 
504 void
mdb_nv_set_value(mdb_var_t * v,uintmax_t l)505 mdb_nv_set_value(mdb_var_t *v, uintmax_t l)
506 {
507 	if (v->v_flags & MDB_NV_RDONLY) {
508 		warn("cannot modify read-only variable '%s'\n", NV_NAME(v));
509 		return;
510 	}
511 
512 	if (v->v_disc)
513 		v->v_disc->disc_set(v, l);
514 	else
515 		v->v_uvalue = l;
516 }
517 
518 void *
mdb_nv_get_cookie(const mdb_var_t * v)519 mdb_nv_get_cookie(const mdb_var_t *v)
520 {
521 	if (v->v_disc)
522 		return ((void *)(uintptr_t)v->v_disc->disc_get(v));
523 
524 	return (MDB_NV_COOKIE(v));
525 }
526 
527 void
mdb_nv_set_cookie(mdb_var_t * v,void * cookie)528 mdb_nv_set_cookie(mdb_var_t *v, void *cookie)
529 {
530 	mdb_nv_set_value(v, (uintmax_t)(uintptr_t)cookie);
531 }
532 
533 const char *
mdb_nv_get_name(const mdb_var_t * v)534 mdb_nv_get_name(const mdb_var_t *v)
535 {
536 	return (NV_NAME(v));
537 }
538 
539 mdb_var_t *
mdb_nv_get_ndef(const mdb_var_t * v)540 mdb_nv_get_ndef(const mdb_var_t *v)
541 {
542 	if (v->v_flags & MDB_NV_OVERLOAD)
543 		return (v->v_ndef);
544 
545 	return (NULL);
546 }
547