xref: /illumos-gate/usr/src/cmd/mdb/common/mdb/mdb_nv.c (revision 065c692a88e4dcdd0c6eadc2476c046d6ee9dd1c) 
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  */
29 
30 #include <mdb/mdb_debug.h>
31 #include <mdb/mdb_string.h>
32 #include <mdb/mdb_modapi.h>
33 #include <mdb/mdb_err.h>
34 #include <mdb/mdb_nv.h>
35 #include <mdb/mdb.h>
36 
37 #define	NV_NAME(v) \
38 	(((v)->v_flags & MDB_NV_EXTNAME) ? (v)->v_ename : (v)->v_lname)
39 
40 #define	NV_SIZE(v) \
41 	(((v)->v_flags & MDB_NV_EXTNAME) ? sizeof (mdb_var_t) : \
42 	sizeof (mdb_var_t) + strlen((v)->v_lname))
43 
44 #define	NV_HASHSZ	211
45 
46 static size_t
47 nv_hashstring(const char *key)
48 {
49 	size_t g, h = 0;
50 	const char *p;
51 
52 	ASSERT(key != NULL);
53 
54 	for (p = key; *p != '\0'; p++) {
55 		h = (h << 4) + *p;
56 
57 		if ((g = (h & 0xf0000000)) != 0) {
58 			h ^= (g >> 24);
59 			h ^= g;
60 		}
61 	}
62 
63 	return (h);
64 }
65 
66 static mdb_var_t *
67 nv_var_alloc(const char *name, const mdb_nv_disc_t *disc,
68 	uintmax_t value, uint_t flags, uint_t um_flags, mdb_var_t *next)
69 {
70 	size_t nbytes;
71 	mdb_var_t *v;
72 
73 	if (flags & MDB_NV_EXTNAME)
74 		nbytes = sizeof (mdb_var_t);
75 	else
76 		nbytes = sizeof (mdb_var_t) + strlen(name);
77 
78 	v = mdb_alloc(nbytes, um_flags);
79 
80 	if (v == NULL)
81 		return (NULL);
82 
83 	if (flags & MDB_NV_EXTNAME) {
84 		v->v_ename = name;
85 		v->v_lname[0] = '\0';
86 	} else {
87 		/*
88 		 * We don't overflow here since the mdb_var_t itself has
89 		 * room for the trailing \0.
90 		 */
91 		(void) strcpy(v->v_lname, name);
92 		v->v_ename = NULL;
93 	}
94 
95 	v->v_uvalue = value;
96 	v->v_flags = flags & ~(MDB_NV_SILENT | MDB_NV_INTERPOS);
97 	v->v_disc = disc;
98 	v->v_next = next;
99 
100 	return (v);
101 }
102 
103 static void
104 nv_var_free(mdb_var_t *v, uint_t um_flags)
105 {
106 	if (um_flags & UM_GC)
107 		return;
108 
109 	if (v->v_flags & MDB_NV_OVERLOAD) {
110 		mdb_var_t *w, *nw;
111 
112 		for (w = v->v_ndef; w != NULL; w = nw) {
113 			nw = w->v_ndef;
114 			mdb_free(w, NV_SIZE(w));
115 		}
116 	}
117 
118 	mdb_free(v, NV_SIZE(v));
119 }
120 
121 /*
122  * Can return NULL only if the nv's memory allocation flags include UM_NOSLEEP
123  */
124 mdb_nv_t *
125 mdb_nv_create(mdb_nv_t *nv, uint_t um_flags)
126 {
127 	nv->nv_hash = mdb_zalloc(sizeof (mdb_var_t *) * NV_HASHSZ, um_flags);
128 
129 	if (nv->nv_hash == NULL)
130 		return (NULL);
131 
132 	nv->nv_hashsz = NV_HASHSZ;
133 	nv->nv_nelems = 0;
134 	nv->nv_iter_elt = NULL;
135 	nv->nv_iter_bucket = 0;
136 	nv->nv_um_flags = um_flags;
137 
138 	return (nv);
139 }
140 
141 void
142 mdb_nv_destroy(mdb_nv_t *nv)
143 {
144 	mdb_var_t *v, *w;
145 	size_t i;
146 
147 	if (nv->nv_um_flags & UM_GC)
148 		return;
149 
150 	for (i = 0; i < nv->nv_hashsz; i++) {
151 		for (v = nv->nv_hash[i]; v != NULL; v = w) {
152 			w = v->v_next;
153 			nv_var_free(v, nv->nv_um_flags);
154 		}
155 	}
156 
157 	mdb_free(nv->nv_hash, sizeof (mdb_var_t *) * NV_HASHSZ);
158 }
159 
160 mdb_var_t *
161 mdb_nv_lookup(mdb_nv_t *nv, const char *name)
162 {
163 	size_t i = nv_hashstring(name) % nv->nv_hashsz;
164 	mdb_var_t *v;
165 
166 	for (v = nv->nv_hash[i]; v != NULL; v = v->v_next) {
167 		if (strcmp(NV_NAME(v), name) == 0)
168 			return (v);
169 	}
170 
171 	return (NULL);
172 }
173 
174 /*
175  * Interpose W in place of V.  We replace V with W in nv_hash, and then
176  * set W's v_ndef overload chain to point at V.
177  */
178 static mdb_var_t *
179 nv_var_interpos(mdb_nv_t *nv, size_t i, mdb_var_t *v, mdb_var_t *w)
180 {
181 	mdb_var_t **pvp = &nv->nv_hash[i];
182 
183 	while (*pvp != v) {
184 		mdb_var_t *vp = *pvp;
185 		ASSERT(vp != NULL);
186 		pvp = &vp->v_next;
187 	}
188 
189 	*pvp = w;
190 	w->v_next = v->v_next;
191 	w->v_ndef = v;
192 	v->v_next = NULL;
193 
194 	return (w);
195 }
196 
197 /*
198  * Add W to the end of V's overload chain.  We simply follow v_ndef to the
199  * end, and then append W.  We don't expect these chains to grow very long.
200  */
201 static mdb_var_t *
202 nv_var_overload(mdb_var_t *v, mdb_var_t *w)
203 {
204 	while (v->v_ndef != NULL)
205 		v = v->v_ndef;
206 
207 	v->v_ndef = w;
208 	return (w);
209 }
210 
211 /*
212  * Can return NULL only if the nv's memory allocation flags include UM_NOSLEEP
213  */
214 mdb_var_t *
215 mdb_nv_insert(mdb_nv_t *nv, const char *name, const mdb_nv_disc_t *disc,
216     uintmax_t value, uint_t flags)
217 {
218 	size_t i = nv_hashstring(name) % nv->nv_hashsz;
219 	mdb_var_t *v;
220 
221 	ASSERT(!(flags & MDB_NV_EXTNAME) || !(flags & MDB_NV_OVERLOAD));
222 	ASSERT(!(flags & MDB_NV_RDONLY) || !(flags & MDB_NV_OVERLOAD));
223 
224 	/*
225 	 * If the specified name is already hashed,
226 	 * and MDB_NV_OVERLOAD is set:	insert new var into overload chain
227 	 * and MDB_NV_RDONLY is set:	leave var unchanged, issue warning
228 	 * otherwise:			update var with new value
229 	 */
230 	for (v = nv->nv_hash[i]; v != NULL; v = v->v_next) {
231 		if (strcmp(NV_NAME(v), name) == 0) {
232 			if (v->v_flags & MDB_NV_OVERLOAD) {
233 				mdb_var_t *w = nv_var_alloc(NV_NAME(v), disc,
234 				    value, flags, nv->nv_um_flags, NULL);
235 
236 				if (w == NULL) {
237 					ASSERT(nv->nv_um_flags & UM_NOSLEEP);
238 					return (NULL);
239 				}
240 
241 				if (flags & MDB_NV_INTERPOS)
242 					v = nv_var_interpos(nv, i, v, w);
243 				else
244 					v = nv_var_overload(v, w);
245 
246 			} else if (v->v_flags & MDB_NV_RDONLY) {
247 				if (!(flags & MDB_NV_SILENT)) {
248 					warn("cannot modify read-only "
249 					    "variable '%s'\n", NV_NAME(v));
250 				}
251 			} else
252 				v->v_uvalue = value;
253 
254 			ASSERT(v != NULL);
255 			return (v);
256 		}
257 	}
258 
259 	/*
260 	 * If the specified name was not found, initialize a new element
261 	 * and add it to the hash table at the beginning of this chain:
262 	 */
263 	v = nv_var_alloc(name, disc, value, flags, nv->nv_um_flags,
264 	    nv->nv_hash[i]);
265 
266 	if (v == NULL) {
267 		ASSERT(nv->nv_um_flags & UM_NOSLEEP);
268 		return (NULL);
269 	}
270 
271 	nv->nv_hash[i] = v;
272 	nv->nv_nelems++;
273 
274 	return (v);
275 }
276 
277 static void
278 nv_var_defn_remove(mdb_var_t *v, mdb_var_t *corpse, uint_t um_flags)
279 {
280 	mdb_var_t *w = v;
281 
282 	while (v->v_ndef != NULL && v->v_ndef != corpse)
283 		v = v->v_ndef;
284 
285 	if (v == NULL) {
286 		fail("var %p ('%s') not found on defn chain of %p\n",
287 		    (void *)corpse, NV_NAME(corpse), (void *)w);
288 	}
289 
290 	v->v_ndef = corpse->v_ndef;
291 	corpse->v_ndef = NULL;
292 	nv_var_free(corpse, um_flags);
293 }
294 
295 void
296 mdb_nv_remove(mdb_nv_t *nv, mdb_var_t *corpse)
297 {
298 	const char *cname = NV_NAME(corpse);
299 	size_t i = nv_hashstring(cname) % nv->nv_hashsz;
300 	mdb_var_t *v = nv->nv_hash[i];
301 	mdb_var_t **pvp;
302 
303 	if (corpse->v_flags & MDB_NV_PERSIST) {
304 		warn("cannot remove persistent variable '%s'\n", cname);
305 		return;
306 	}
307 
308 	if (v != corpse) {
309 		do {
310 			if (strcmp(NV_NAME(v), cname) == 0) {
311 				if (corpse->v_flags & MDB_NV_OVERLOAD) {
312 					nv_var_defn_remove(v, corpse,
313 					    nv->nv_um_flags);
314 					return; /* No v_next changes needed */
315 				} else
316 					goto notfound;
317 			}
318 
319 			if (v->v_next == corpse)
320 				break; /* Corpse is next on the chain */
321 
322 		} while ((v = v->v_next) != NULL);
323 
324 		if (v == NULL)
325 			goto notfound;
326 
327 		pvp = &v->v_next;
328 	} else
329 		pvp = &nv->nv_hash[i];
330 
331 	if ((corpse->v_flags & MDB_NV_OVERLOAD) && corpse->v_ndef != NULL) {
332 		corpse->v_ndef->v_next = corpse->v_next;
333 		*pvp = corpse->v_ndef;
334 		corpse->v_ndef = NULL;
335 	} else {
336 		*pvp = corpse->v_next;
337 		nv->nv_nelems--;
338 	}
339 
340 	nv_var_free(corpse, nv->nv_um_flags);
341 	return;
342 
343 notfound:
344 	fail("var %p ('%s') not found on hash chain: nv=%p [%lu]\n",
345 	    (void *)corpse, cname, (void *)nv, (ulong_t)i);
346 }
347 
348 void
349 mdb_nv_rewind(mdb_nv_t *nv)
350 {
351 	size_t i;
352 
353 	for (i = 0; i < nv->nv_hashsz; i++) {
354 		if (nv->nv_hash[i] != NULL)
355 			break;
356 	}
357 
358 	nv->nv_iter_elt = i < nv->nv_hashsz ? nv->nv_hash[i] : NULL;
359 	nv->nv_iter_bucket = i;
360 }
361 
362 mdb_var_t *
363 mdb_nv_advance(mdb_nv_t *nv)
364 {
365 	mdb_var_t *v = nv->nv_iter_elt;
366 	size_t i;
367 
368 	if (v == NULL)
369 		return (NULL);
370 
371 	if (v->v_next != NULL) {
372 		nv->nv_iter_elt = v->v_next;
373 		return (v);
374 	}
375 
376 	for (i = nv->nv_iter_bucket + 1; i < nv->nv_hashsz; i++) {
377 		if (nv->nv_hash[i] != NULL)
378 			break;
379 	}
380 
381 	nv->nv_iter_elt = i < nv->nv_hashsz ? nv->nv_hash[i] : NULL;
382 	nv->nv_iter_bucket = i;
383 
384 	return (v);
385 }
386 
387 mdb_var_t *
388 mdb_nv_peek(mdb_nv_t *nv)
389 {
390 	return (nv->nv_iter_elt);
391 }
392 
393 size_t
394 mdb_nv_size(mdb_nv_t *nv)
395 {
396 	return (nv->nv_nelems);
397 }
398 
399 static int
400 nv_compare(const mdb_var_t **lp, const mdb_var_t **rp)
401 {
402 	return (strcmp(mdb_nv_get_name(*lp), mdb_nv_get_name(*rp)));
403 }
404 
405 void
406 mdb_nv_sort_iter(mdb_nv_t *nv, int (*func)(mdb_var_t *, void *),
407     void *private, uint_t um_flags)
408 {
409 	mdb_var_t **vps =
410 	    mdb_alloc(nv->nv_nelems * sizeof (mdb_var_t *), um_flags);
411 
412 	if (nv->nv_nelems != 0 && vps != NULL) {
413 		mdb_var_t *v, **vpp = vps;
414 		size_t i;
415 
416 		for (mdb_nv_rewind(nv); (v = mdb_nv_advance(nv)) != NULL; )
417 			*vpp++ = v;
418 
419 		qsort(vps, nv->nv_nelems, sizeof (mdb_var_t *),
420 		    (int (*)(const void *, const void *))nv_compare);
421 
422 		for (vpp = vps, i = 0; i < nv->nv_nelems; i++) {
423 			if (func(*vpp++, private) == -1)
424 				break;
425 		}
426 
427 		if (!(um_flags & UM_GC))
428 			mdb_free(vps, nv->nv_nelems * sizeof (mdb_var_t *));
429 	}
430 }
431 
432 void
433 mdb_nv_defn_iter(mdb_var_t *v, int (*func)(mdb_var_t *, void *), void *private)
434 {
435 	if (func(v, private) == -1 || !(v->v_flags & MDB_NV_OVERLOAD))
436 		return;
437 
438 	for (v = v->v_ndef; v != NULL; v = v->v_ndef) {
439 		if (func(v, private) == -1)
440 			break;
441 	}
442 }
443 
444 uintmax_t
445 mdb_nv_get_value(const mdb_var_t *v)
446 {
447 	if (v->v_disc)
448 		return (v->v_disc->disc_get(v));
449 
450 	return (v->v_uvalue);
451 }
452 
453 void
454 mdb_nv_set_value(mdb_var_t *v, uintmax_t l)
455 {
456 	if (v->v_flags & MDB_NV_RDONLY) {
457 		warn("cannot modify read-only variable '%s'\n", NV_NAME(v));
458 		return;
459 	}
460 
461 	if (v->v_disc)
462 		v->v_disc->disc_set(v, l);
463 	else
464 		v->v_uvalue = l;
465 }
466 
467 void *
468 mdb_nv_get_cookie(const mdb_var_t *v)
469 {
470 	if (v->v_disc)
471 		return ((void *)(uintptr_t)v->v_disc->disc_get(v));
472 
473 	return (MDB_NV_COOKIE(v));
474 }
475 
476 void
477 mdb_nv_set_cookie(mdb_var_t *v, void *cookie)
478 {
479 	mdb_nv_set_value(v, (uintmax_t)(uintptr_t)cookie);
480 }
481 
482 const char *
483 mdb_nv_get_name(const mdb_var_t *v)
484 {
485 	return (NV_NAME(v));
486 }
487 
488 mdb_var_t *
489 mdb_nv_get_ndef(const mdb_var_t *v)
490 {
491 	if (v->v_flags & MDB_NV_OVERLOAD)
492 		return (v->v_ndef);
493 
494 	return (NULL);
495 }
496