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 ((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
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 = *(ushort_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 ctf_type_t *
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) && CTF_TYPE_ISPARENT(type) &&
224 (fp = fp->ctf_parent) == NULL) {
225 (void) ctf_set_errno(*fpp, ECTF_NOPARENT);
226 return (NULL);
227 }
228
229 type = CTF_TYPE_TO_INDEX(type);
230 if (type > 0 && type <= fp->ctf_typemax) {
231 *fpp = fp; /* function returns ending CTF container */
232 return (LCTF_INDEX_TO_TYPEPTR(fp, type));
233 }
234
235 (void) ctf_set_errno(fp, ECTF_BADID);
236 return (NULL);
237 }
238
239 /*
240 * Given a symbol table index, return the info for the function described
241 * by the corresponding entry in the symbol table.
242 */
243 int
244 ctf_func_info(ctf_file_t *fp, ulong_t symidx, ctf_funcinfo_t *fip)
245 {
246 const ctf_sect_t *sp = &fp->ctf_symtab;
247 const ushort_t *dp;
248 ushort_t info, kind, n;
249
250 if (sp->cts_data == NULL)
251 return (ctf_set_errno(fp, ECTF_NOSYMTAB));
252
253 if (symidx >= fp->ctf_nsyms)
254 return (ctf_set_errno(fp, EINVAL));
255
256 if (sp->cts_entsize == sizeof (Elf32_Sym)) {
257 const Elf32_Sym *symp = (Elf32_Sym *)sp->cts_data + symidx;
258 if (ELF32_ST_TYPE(symp->st_info) != STT_FUNC)
259 return (ctf_set_errno(fp, ECTF_NOTFUNC));
260 } else {
261 const Elf64_Sym *symp = (Elf64_Sym *)sp->cts_data + symidx;
262 if (ELF64_ST_TYPE(symp->st_info) != STT_FUNC)
263 return (ctf_set_errno(fp, ECTF_NOTFUNC));
264 }
265
266 if (fp->ctf_sxlate[symidx] == -1u)
267 return (ctf_set_errno(fp, ECTF_NOFUNCDAT));
268
269 dp = (ushort_t *)((uintptr_t)fp->ctf_buf + fp->ctf_sxlate[symidx]);
270
271 info = *dp++;
272 kind = LCTF_INFO_KIND(fp, info);
273 n = LCTF_INFO_VLEN(fp, info);
274
275 if (kind == CTF_K_UNKNOWN && n == 0)
276 return (ctf_set_errno(fp, ECTF_NOFUNCDAT));
277
278 if (kind != CTF_K_FUNCTION)
279 return (ctf_set_errno(fp, ECTF_CORRUPT));
280
281 fip->ctc_return = *dp++;
282 fip->ctc_argc = n;
283 fip->ctc_flags = 0;
284
285 if (n != 0 && dp[n - 1] == 0) {
286 fip->ctc_flags |= CTF_FUNC_VARARG;
287 fip->ctc_argc--;
288 }
289
290 return (0);
291 }
292
293 /*
294 * Given a symbol table index, return the arguments for the function described
295 * by the corresponding entry in the symbol table.
296 */
297 int
298 ctf_func_args(ctf_file_t *fp, ulong_t symidx, uint_t argc, ctf_id_t *argv)
299 {
300 const ushort_t *dp;
301 ctf_funcinfo_t f;
302
303 if (ctf_func_info(fp, symidx, &f) == CTF_ERR)
304 return (CTF_ERR); /* errno is set for us */
305
306 /*
307 * The argument data is two ushort_t's past the translation table
308 * offset: one for the function info, and one for the return type.
309 */
310 dp = (ushort_t *)((uintptr_t)fp->ctf_buf + fp->ctf_sxlate[symidx]) + 2;
311
312 for (argc = MIN(argc, f.ctc_argc); argc != 0; argc--)
313 *argv++ = *dp++;
314
315 return (0);
316 }
317
318 /*
319 * Unlike the normal lookup routines, ctf_dyn_*() variants consult both the
320 * processed CTF contents of a ctf_file_t as well as the dynamic types in the
321 * dtdef list.
322 */
323
324 const ctf_type_t *
325 ctf_dyn_lookup_by_id(ctf_file_t *fp, ctf_id_t id)
326 {
327 ctf_file_t **fpp = &fp;
328 const ctf_type_t *t;
329 ctf_dtdef_t *dtd;
330
331 if ((t = ctf_lookup_by_id(fpp, id)) != NULL)
332 return (t);
333
334 if ((dtd = ctf_dtd_lookup(fp, id)) == NULL)
335 return (NULL);
336
337 return (&dtd->dtd_data);
338 }
339
340 int
341 ctf_dyn_array_info(ctf_file_t *infp, ctf_id_t id, ctf_arinfo_t *arinfop)
342 {
343 ctf_file_t *fp = infp;
344 const ctf_type_t *t;
345 ctf_dtdef_t *dtd;
346
347 if ((t = ctf_lookup_by_id(&fp, id)) != NULL) {
348
349 if (LCTF_INFO_KIND(fp, t->ctt_info) != CTF_K_ARRAY)
350 return (ctf_set_errno(infp, ECTF_NOTARRAY));
351
352 return (ctf_array_info(fp, id, arinfop));
353 }
354
355 if ((dtd = ctf_dtd_lookup(fp, id)) == NULL)
356 return (ctf_set_errno(infp, ENOENT));
357
358 if (LCTF_INFO_KIND(fp, dtd->dtd_data.ctt_info) != CTF_K_ARRAY)
359 return (ctf_set_errno(infp, ECTF_NOTARRAY));
360
361 bcopy(&dtd->dtd_u.dtu_arr, arinfop, sizeof (*arinfop));
362 return (0);
363 }