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/*
24 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
25 * Use is subject to license terms.
26 */
27
28#pragma ident	"%Z%%M%	%I%	%E% SMI"
29
30#include <sys/sysmacros.h>
31#include <ctf_impl.h>
32
33/*
34 * Compare the given input string and length against a table of known C storage
35 * qualifier keywords.  We just ignore these in ctf_lookup_by_name, below.  To
36 * do this quickly, we use a pre-computed Perfect Hash Function similar to the
37 * technique originally described in the classic paper:
38 *
39 * R.J. Cichelli, "Minimal Perfect Hash Functions Made Simple",
40 * Communications of the ACM, Volume 23, Issue 1, January 1980, pp. 17-19.
41 *
42 * For an input string S of length N, we use hash H = S[N - 1] + N - 105, which
43 * for the current set of qualifiers yields a unique H in the range [0 .. 20].
44 * The hash can be modified when the keyword set changes as necessary.  We also
45 * store the length of each keyword and check it prior to the final strcmp().
46 */
47static int
48isqualifier(const char *s, size_t len)
49{
50	static const struct qual {
51		const char *q_name;
52		size_t q_len;
53	} qhash[] = {
54		{ "static", 6 }, { "", 0 }, { "", 0 }, { "", 0 },
55		{ "volatile", 8 }, { "", 0 }, { "", 0 }, { "", 0 }, { "", 0 },
56		{ "", 0 }, { "auto", 4 }, { "extern", 6 }, { "", 0 }, { "", 0 },
57		{ "", 0 }, { "", 0 }, { "const", 5 }, { "register", 8 },
58		{ "", 0 }, { "restrict", 8 }, { "_Restrict", 9 }
59	};
60
61	int h = s[len - 1] + (int)len - 105;
62	const struct qual *qp;
63
64	if (h < 0 || h >= sizeof (qhash) / sizeof (qhash[0]))
65		return (0);
66	qp = &qhash[h];
67	return (len == qp->q_len && strncmp(qp->q_name, s, qp->q_len) == 0);
68}
69
70/*
71 * Attempt to convert the given C type name into the corresponding CTF type ID.
72 * It is not possible to do complete and proper conversion of type names
73 * without implementing a more full-fledged parser, which is necessary to
74 * handle things like types that are function pointers to functions that
75 * have arguments that are function pointers, and fun stuff like that.
76 * Instead, this function implements a very simple conversion algorithm that
77 * finds the things that we actually care about: structs, unions, enums,
78 * integers, floats, typedefs, and pointers to any of these named types.
79 */
80ctf_id_t
81ctf_lookup_by_name(ctf_file_t *fp, const char *name)
82{
83	static const char delimiters[] = " \t\n\r\v\f*";
84
85	const ctf_lookup_t *lp;
86	const ctf_helem_t *hp;
87	const char *p, *q, *end;
88	ctf_id_t type = 0;
89	ctf_id_t ntype, ptype;
90
91	if (name == NULL)
92		return (ctf_set_errno(fp, EINVAL));
93
94	for (p = name, end = name + strlen(name); *p != '\0'; p = q) {
95		while (isspace(*p))
96			p++; /* skip leading ws */
97
98		if (p == end)
99			break;
100
101		if ((q = strpbrk(p + 1, delimiters)) == NULL)
102			q = end; /* compare until end */
103
104		if (*p == '*') {
105			/*
106			 * Find a pointer to type by looking in fp->ctf_ptrtab.
107			 * If we can't find a pointer to the given type, see if
108			 * we can compute a pointer to the type resulting from
109			 * resolving the type down to its base type and use
110			 * that instead.  This helps with cases where the CTF
111			 * data includes "struct foo *" but not "foo_t *" and
112			 * the user tries to access "foo_t *" in the debugger.
113			 */
114			ntype = fp->ctf_ptrtab[CTF_TYPE_TO_INDEX(type)];
115			if (ntype == 0) {
116				ntype = ctf_type_resolve(fp, type);
117				if (ntype == CTF_ERR || (ntype = fp->ctf_ptrtab[
118				    CTF_TYPE_TO_INDEX(ntype)]) == 0) {
119					(void) ctf_set_errno(fp, ECTF_NOTYPE);
120					goto err;
121				}
122			}
123
124			type = CTF_INDEX_TO_TYPE(ntype,
125			    (fp->ctf_flags & LCTF_CHILD));
126
127			q = p + 1;
128			continue;
129		}
130
131		if (isqualifier(p, (size_t)(q - p)))
132			continue; /* skip qualifier keyword */
133
134		for (lp = fp->ctf_lookups; lp->ctl_prefix != NULL; lp++) {
135			if (lp->ctl_prefix[0] == '\0' ||
136			    strncmp(p, lp->ctl_prefix, (size_t)(q - p)) == 0) {
137				for (p += lp->ctl_len; isspace(*p); p++)
138					continue; /* skip prefix and next ws */
139
140				if ((q = strchr(p, '*')) == NULL)
141					q = end;  /* compare until end */
142
143				while (isspace(q[-1]))
144					q--;	  /* exclude trailing ws */
145
146				if ((hp = ctf_hash_lookup(lp->ctl_hash, fp, p,
147				    (size_t)(q - p))) == NULL) {
148					(void) ctf_set_errno(fp, ECTF_NOTYPE);
149					goto err;
150				}
151
152				type = hp->h_type;
153				break;
154			}
155		}
156
157		if (lp->ctl_prefix == NULL) {
158			(void) ctf_set_errno(fp, ECTF_NOTYPE);
159			goto err;
160		}
161	}
162
163	if (*p != '\0' || type == 0)
164		return (ctf_set_errno(fp, ECTF_SYNTAX));
165
166	return (type);
167
168err:
169	if (fp->ctf_parent != NULL &&
170	    (ptype = ctf_lookup_by_name(fp->ctf_parent, name)) != CTF_ERR)
171		return (ptype);
172
173	return (CTF_ERR);
174}
175
176/*
177 * Given a symbol table index, return the type of the data object described
178 * by the corresponding entry in the symbol table.
179 */
180ctf_id_t
181ctf_lookup_by_symbol(ctf_file_t *fp, ulong_t symidx)
182{
183	const ctf_sect_t *sp = &fp->ctf_symtab;
184	ctf_id_t type;
185
186	if (sp->cts_data == NULL)
187		return (ctf_set_errno(fp, ECTF_NOSYMTAB));
188
189	if (symidx >= fp->ctf_nsyms)
190		return (ctf_set_errno(fp, EINVAL));
191
192	if (sp->cts_entsize == sizeof (Elf32_Sym)) {
193		const Elf32_Sym *symp = (Elf32_Sym *)sp->cts_data + symidx;
194		if (ELF32_ST_TYPE(symp->st_info) != STT_OBJECT)
195			return (ctf_set_errno(fp, ECTF_NOTDATA));
196	} else {
197		const Elf64_Sym *symp = (Elf64_Sym *)sp->cts_data + symidx;
198		if (ELF64_ST_TYPE(symp->st_info) != STT_OBJECT)
199			return (ctf_set_errno(fp, ECTF_NOTDATA));
200	}
201
202	if (fp->ctf_sxlate[symidx] == -1u)
203		return (ctf_set_errno(fp, ECTF_NOTYPEDAT));
204
205	type = *(ushort_t *)((uintptr_t)fp->ctf_buf + fp->ctf_sxlate[symidx]);
206	if (type == 0)
207		return (ctf_set_errno(fp, ECTF_NOTYPEDAT));
208
209	return (type);
210}
211
212/*
213 * Return the pointer to the internal CTF type data corresponding to the
214 * given type ID.  If the ID is invalid, the function returns NULL.
215 * This function is not exported outside of the library.
216 */
217const ctf_type_t *
218ctf_lookup_by_id(ctf_file_t **fpp, ctf_id_t type)
219{
220	ctf_file_t *fp = *fpp; /* caller passes in starting CTF container */
221
222	if ((fp->ctf_flags & LCTF_CHILD) && CTF_TYPE_ISPARENT(type) &&
223	    (fp = fp->ctf_parent) == NULL) {
224		(void) ctf_set_errno(*fpp, ECTF_NOPARENT);
225		return (NULL);
226	}
227
228	type = CTF_TYPE_TO_INDEX(type);
229	if (type > 0 && type <= fp->ctf_typemax) {
230		*fpp = fp; /* function returns ending CTF container */
231		return (LCTF_INDEX_TO_TYPEPTR(fp, type));
232	}
233
234	(void) ctf_set_errno(fp, ECTF_BADID);
235	return (NULL);
236}
237
238/*
239 * Given a symbol table index, return the info for the function described
240 * by the corresponding entry in the symbol table.
241 */
242int
243ctf_func_info(ctf_file_t *fp, ulong_t symidx, ctf_funcinfo_t *fip)
244{
245	const ctf_sect_t *sp = &fp->ctf_symtab;
246	const ushort_t *dp;
247	ushort_t info, kind, n;
248
249	if (sp->cts_data == NULL)
250		return (ctf_set_errno(fp, ECTF_NOSYMTAB));
251
252	if (symidx >= fp->ctf_nsyms)
253		return (ctf_set_errno(fp, EINVAL));
254
255	if (sp->cts_entsize == sizeof (Elf32_Sym)) {
256		const Elf32_Sym *symp = (Elf32_Sym *)sp->cts_data + symidx;
257		if (ELF32_ST_TYPE(symp->st_info) != STT_FUNC)
258			return (ctf_set_errno(fp, ECTF_NOTFUNC));
259	} else {
260		const Elf64_Sym *symp = (Elf64_Sym *)sp->cts_data + symidx;
261		if (ELF64_ST_TYPE(symp->st_info) != STT_FUNC)
262			return (ctf_set_errno(fp, ECTF_NOTFUNC));
263	}
264
265	if (fp->ctf_sxlate[symidx] == -1u)
266		return (ctf_set_errno(fp, ECTF_NOFUNCDAT));
267
268	dp = (ushort_t *)((uintptr_t)fp->ctf_buf + fp->ctf_sxlate[symidx]);
269
270	info = *dp++;
271	kind = LCTF_INFO_KIND(fp, info);
272	n = LCTF_INFO_VLEN(fp, info);
273
274	if (kind == CTF_K_UNKNOWN && n == 0)
275		return (ctf_set_errno(fp, ECTF_NOFUNCDAT));
276
277	if (kind != CTF_K_FUNCTION)
278		return (ctf_set_errno(fp, ECTF_CORRUPT));
279
280	fip->ctc_return = *dp++;
281	fip->ctc_argc = n;
282	fip->ctc_flags = 0;
283
284	if (n != 0 && dp[n - 1] == 0) {
285		fip->ctc_flags |= CTF_FUNC_VARARG;
286		fip->ctc_argc--;
287	}
288
289	return (0);
290}
291
292/*
293 * Given a symbol table index, return the arguments for the function described
294 * by the corresponding entry in the symbol table.
295 */
296int
297ctf_func_args(ctf_file_t *fp, ulong_t symidx, uint_t argc, ctf_id_t *argv)
298{
299	const ushort_t *dp;
300	ctf_funcinfo_t f;
301
302	if (ctf_func_info(fp, symidx, &f) == CTF_ERR)
303		return (CTF_ERR); /* errno is set for us */
304
305	/*
306	 * The argument data is two ushort_t's past the translation table
307	 * offset: one for the function info, and one for the return type.
308	 */
309	dp = (ushort_t *)((uintptr_t)fp->ctf_buf + fp->ctf_sxlate[symidx]) + 2;
310
311	for (argc = MIN(argc, f.ctc_argc); argc != 0; argc--)
312		*argv++ = *dp++;
313
314	return (0);
315}
316