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 /*
29 * Copyright 2019, Joyent, Inc.
30 */
31
32 #include <sys/sysmacros.h>
33 #include <ctf_impl.h>
34
35 /*
36 * Compare the given input string and length against a table of known C storage
37 * qualifier keywords. We just ignore these in ctf_lookup_by_name, below. To
38 * do this quickly, we use a pre-computed Perfect Hash Function similar to the
39 * technique originally described in the classic paper:
40 *
41 * R.J. Cichelli, "Minimal Perfect Hash Functions Made Simple",
42 * Communications of the ACM, Volume 23, Issue 1, January 1980, pp. 17-19.
43 *
44 * For an input string S of length N, we use hash H = S[N - 1] + N - 105, which
45 * for the current set of qualifiers yields a unique H in the range [0 .. 20].
46 * The hash can be modified when the keyword set changes as necessary. We also
47 * store the length of each keyword and check it prior to the final strcmp().
48 */
49 static int
50 isqualifier(const char *s, size_t len)
51 {
52 static const struct qual {
53 const char *q_name;
54 size_t q_len;
55 } qhash[] = {
56 { "static", 6 }, { "", 0 }, { "", 0 }, { "", 0 },
57 { "volatile", 8 }, { "", 0 }, { "", 0 }, { "", 0 }, { "", 0 },
58 { "", 0 }, { "auto", 4 }, { "extern", 6 }, { "", 0 }, { "", 0 },
59 { "", 0 }, { "", 0 }, { "const", 5 }, { "register", 8 },
60 { "", 0 }, { "restrict", 8 }, { "_Restrict", 9 }
61 };
62
63 int h = s[len - 1] + (int)len - 105;
64 const struct qual *qp = &qhash[h];
65
66 return (h >= 0 && h < sizeof (qhash) / sizeof (qhash[0]) &&
67 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
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[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
168 err:
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 */
180 ctf_id_t
181 ctf_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 */
217 const ctf_type_t *
218 ctf_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 */
242 int
243 ctf_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 */
296 int
297 ctf_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
317 /*
318 * Unlike the normal lookup routines, ctf_dyn_*() variants consult both the
319 * processed CTF contents of a ctf_file_t as well as the dynamic types in the
320 * dtdef list.
321 */
322
323 const ctf_type_t *
324 ctf_dyn_lookup_by_id(ctf_file_t *fp, ctf_id_t id)
325 {
326 ctf_file_t **fpp = &fp;
327 const ctf_type_t *t;
328 ctf_dtdef_t *dtd;
329
330 if ((t = ctf_lookup_by_id(fpp, id)) != NULL)
331 return (t);
332
333 if ((dtd = ctf_dtd_lookup(fp, id)) == NULL)
334 return (NULL);
335
336 return (&dtd->dtd_data);
337 }
338
339 int
340 ctf_dyn_array_info(ctf_file_t *infp, ctf_id_t id, ctf_arinfo_t *arinfop)
341 {
342 ctf_file_t *fp = infp;
343 const ctf_type_t *t;
344 ctf_dtdef_t *dtd;
345
346 if ((t = ctf_lookup_by_id(&fp, id)) != NULL) {
347
348 if (LCTF_INFO_KIND(fp, t->ctt_info) != CTF_K_ARRAY)
349 return (ctf_set_errno(infp, ECTF_NOTARRAY));
350
351 return (ctf_array_info(fp, id, arinfop));
352 }
353
354 if ((dtd = ctf_dtd_lookup(fp, id)) == NULL)
355 return (ctf_set_errno(infp, ENOENT));
356
357 if (LCTF_INFO_KIND(fp, dtd->dtd_data.ctt_info) != CTF_K_ARRAY)
358 return (ctf_set_errno(infp, ECTF_NOTARRAY));
359
360 bcopy(&dtd->dtd_u.dtu_arr, arinfop, sizeof (*arinfop));
361 return (0);
362 }