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 */
47 static int
isqualifier(const char * s,size_t len)48 isqualifier(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 */
80 ctf_id_t
ctf_lookup_by_name(ctf_file_t * fp,const char * name)81 ctf_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[LCTF_TYPE_TO_INDEX(fp, type)];
115 if (ntype == 0) {
116 ntype = ctf_type_resolve(fp, type);
117 if (ntype == CTF_ERR || (ntype = fp->ctf_ptrtab[
118 LCTF_TYPE_TO_INDEX(fp, ntype)]) == 0) {
119 (void) ctf_set_errno(fp, ECTF_NOTYPE);
120 goto err;
121 }
122 }
123
124 type = LCTF_INDEX_TO_TYPE(fp, 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 ((size_t)(q - p) >= lp->ctl_len && strncmp(p,
137 lp->ctl_prefix, (size_t)(q - p)) == 0)) {
138 for (p += lp->ctl_len; isspace(*p); p++)
139 continue; /* skip prefix and next ws */
140
141 if ((q = strchr(p, '*')) == NULL)
142 q = end; /* compare until end */
143
144 while (isspace(q[-1]))
145 q--; /* exclude trailing ws */
146
147 if ((hp = ctf_hash_lookup(lp->ctl_hash, fp, p,
148 (size_t)(q - p))) == NULL) {
149 (void) ctf_set_errno(fp, ECTF_NOTYPE);
150 goto err;
151 }
152
153 type = hp->h_type;
154 break;
155 }
156 }
157
158 if (lp->ctl_prefix == NULL) {
159 (void) ctf_set_errno(fp, ECTF_NOTYPE);
160 goto err;
161 }
162 }
163
164 if (*p != '\0' || type == 0)
165 return (ctf_set_errno(fp, ECTF_SYNTAX));
166
167 return (type);
168
169 err:
170 if (fp->ctf_parent != NULL &&
171 (ptype = ctf_lookup_by_name(fp->ctf_parent, name)) != CTF_ERR)
172 return (ptype);
173
174 return (CTF_ERR);
175 }
176
177 /*
178 * Given a symbol table index, return the type of the data object described
179 * by the corresponding entry in the symbol table.
180 */
181 ctf_id_t
ctf_lookup_by_symbol(ctf_file_t * fp,ulong_t symidx)182 ctf_lookup_by_symbol(ctf_file_t *fp, ulong_t symidx)
183 {
184 const ctf_sect_t *sp = &fp->ctf_symtab;
185 ctf_id_t type;
186
187 if (sp->cts_data == NULL)
188 return (ctf_set_errno(fp, ECTF_NOSYMTAB));
189
190 if (symidx >= fp->ctf_nsyms)
191 return (ctf_set_errno(fp, EINVAL));
192
193 if (sp->cts_entsize == sizeof (Elf32_Sym)) {
194 const Elf32_Sym *symp = (Elf32_Sym *)sp->cts_data + symidx;
195 if (ELF32_ST_TYPE(symp->st_info) != STT_OBJECT)
196 return (ctf_set_errno(fp, ECTF_NOTDATA));
197 } else {
198 const Elf64_Sym *symp = (Elf64_Sym *)sp->cts_data + symidx;
199 if (ELF64_ST_TYPE(symp->st_info) != STT_OBJECT)
200 return (ctf_set_errno(fp, ECTF_NOTDATA));
201 }
202
203 if (fp->ctf_sxlate[symidx] == -1u)
204 return (ctf_set_errno(fp, ECTF_NOTYPEDAT));
205
206 type = *(uint_t *)((uintptr_t)fp->ctf_buf + fp->ctf_sxlate[symidx]);
207 if (type == 0)
208 return (ctf_set_errno(fp, ECTF_NOTYPEDAT));
209
210 return (type);
211 }
212
213 /*
214 * Return the pointer to the internal CTF type data corresponding to the
215 * given type ID. If the ID is invalid, the function returns NULL.
216 * This function is not exported outside of the library.
217 */
218 const void *
ctf_lookup_by_id(ctf_file_t ** fpp,ctf_id_t type)219 ctf_lookup_by_id(ctf_file_t **fpp, ctf_id_t type)
220 {
221 ctf_file_t *fp = *fpp; /* caller passes in starting CTF container */
222
223 if ((fp->ctf_flags & LCTF_CHILD) && LCTF_TYPE_ISPARENT(fp, type)) {
224 if (fp->ctf_parent == NULL) {
225 (void) ctf_set_errno(*fpp, ECTF_NOPARENT);
226 return (NULL);
227 }
228
229 /* The parent may be using a different CTF version. */
230 type = LCTF_TYPE_TO_INDEX(fp, type);
231 fp = fp->ctf_parent;
232 } else {
233 type = LCTF_TYPE_TO_INDEX(fp, type);
234 }
235
236 if (type > 0 && type <= fp->ctf_typemax) {
237 *fpp = fp; /* function returns ending CTF container */
238 return (LCTF_INDEX_TO_TYPEPTR(fp, type));
239 }
240
241 (void) ctf_set_errno(fp, ECTF_BADID);
242 return (NULL);
243 }
244
245 /*
246 * Given a symbol table index, return the info for the function described
247 * by the corresponding entry in the symbol table.
248 */
249 int
ctf_func_info(ctf_file_t * fp,ulong_t symidx,ctf_funcinfo_t * fip)250 ctf_func_info(ctf_file_t *fp, ulong_t symidx, ctf_funcinfo_t *fip)
251 {
252 const ctf_sect_t *sp = &fp->ctf_symtab;
253 const uint_t *dp;
254 uint_t info, kind, n;
255
256 if (sp->cts_data == NULL)
257 return (ctf_set_errno(fp, ECTF_NOSYMTAB));
258
259 if (symidx >= fp->ctf_nsyms)
260 return (ctf_set_errno(fp, EINVAL));
261
262 if (sp->cts_entsize == sizeof (Elf32_Sym)) {
263 const Elf32_Sym *symp = (Elf32_Sym *)sp->cts_data + symidx;
264 if (ELF32_ST_TYPE(symp->st_info) != STT_FUNC)
265 return (ctf_set_errno(fp, ECTF_NOTFUNC));
266 } else {
267 const Elf64_Sym *symp = (Elf64_Sym *)sp->cts_data + symidx;
268 if (ELF64_ST_TYPE(symp->st_info) != STT_FUNC)
269 return (ctf_set_errno(fp, ECTF_NOTFUNC));
270 }
271
272 if (fp->ctf_sxlate[symidx] == -1u)
273 return (ctf_set_errno(fp, ECTF_NOFUNCDAT));
274
275 dp = (uint_t *)((uintptr_t)fp->ctf_buf + fp->ctf_sxlate[symidx]);
276
277 info = *dp++;
278 kind = LCTF_INFO_KIND(fp, info);
279 n = LCTF_INFO_VLEN(fp, info);
280
281 if (kind == CTF_K_UNKNOWN && n == 0)
282 return (ctf_set_errno(fp, ECTF_NOFUNCDAT));
283
284 if (kind != CTF_K_FUNCTION)
285 return (ctf_set_errno(fp, ECTF_CORRUPT));
286
287 fip->ctc_return = *dp++;
288 fip->ctc_argc = n;
289 fip->ctc_flags = 0;
290
291 if (n != 0 && dp[n - 1] == 0) {
292 fip->ctc_flags |= CTF_FUNC_VARARG;
293 fip->ctc_argc--;
294 }
295
296 return (0);
297 }
298
299 /*
300 * Given a symbol table index, return the arguments for the function described
301 * by the corresponding entry in the symbol table.
302 */
303 int
ctf_func_args(ctf_file_t * fp,ulong_t symidx,uint_t argc,ctf_id_t * argv)304 ctf_func_args(ctf_file_t *fp, ulong_t symidx, uint_t argc, ctf_id_t *argv)
305 {
306 const uint_t *dp;
307 ctf_funcinfo_t f;
308
309 if (ctf_func_info(fp, symidx, &f) == CTF_ERR)
310 return (CTF_ERR); /* errno is set for us */
311
312 /*
313 * The argument data is two uint_t's past the translation table
314 * offset: one for the function info, and one for the return type.
315 */
316 dp = (uint_t *)((uintptr_t)fp->ctf_buf + fp->ctf_sxlate[symidx]) + 2;
317
318 for (argc = MIN(argc, f.ctc_argc); argc != 0; argc--)
319 *argv++ = *dp++;
320
321 return (0);
322 }
323