1 /* $NetBSD: dwarf_loclist.c,v 1.5 2024/03/03 17:37:31 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2009,2014 Kai Wang
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include "_libdwarf.h"
30
31 __RCSID("$NetBSD: dwarf_loclist.c,v 1.5 2024/03/03 17:37:31 christos Exp $");
32 ELFTC_VCSID("Id: dwarf_loclist.c 3066 2014-06-06 19:36:06Z kaiwang27");
33
34 static int
copy_locdesc(Dwarf_Debug dbg,Dwarf_Locdesc * dst,Dwarf_Locdesc * src,Dwarf_Error * error)35 copy_locdesc(Dwarf_Debug dbg, Dwarf_Locdesc *dst, Dwarf_Locdesc *src,
36 Dwarf_Error *error)
37 {
38
39 assert(src != NULL && dst != NULL);
40
41 dst->ld_lopc = src->ld_lopc;
42 dst->ld_hipc = src->ld_hipc;
43 dst->ld_cents = src->ld_cents;
44
45 if (dst->ld_cents > 0) {
46 dst->ld_s = calloc(dst->ld_cents, sizeof(Dwarf_Loc));
47 if (dst->ld_s == NULL) {
48 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
49 return (DW_DLE_MEMORY);
50 }
51 memcpy(dst->ld_s, src->ld_s, src->ld_cents *
52 sizeof(Dwarf_Loc));
53 } else
54 dst->ld_s = NULL;
55
56 return (DW_DLE_NONE);
57 }
58
59 int
dwarf_loclist_n(Dwarf_Attribute at,Dwarf_Locdesc *** llbuf,Dwarf_Signed * listlen,Dwarf_Error * error)60 dwarf_loclist_n(Dwarf_Attribute at, Dwarf_Locdesc ***llbuf,
61 Dwarf_Signed *listlen, Dwarf_Error *error)
62 {
63 Dwarf_Debug dbg;
64 int ret;
65
66 dbg = at != NULL ? at->at_die->die_dbg : NULL;
67
68 if (at == NULL || llbuf == NULL || listlen == NULL) {
69 DWARF_SET_ERROR(dbg, error, DW_DLE_ARGUMENT);
70 return (DW_DLV_ERROR);
71 }
72
73 switch (at->at_attrib) {
74 case DW_AT_location:
75 case DW_AT_string_length:
76 case DW_AT_return_addr:
77 case DW_AT_data_member_location:
78 case DW_AT_frame_base:
79 case DW_AT_segment:
80 case DW_AT_static_link:
81 case DW_AT_use_location:
82 case DW_AT_vtable_elem_location:
83 switch (at->at_form) {
84 case DW_FORM_data4:
85 case DW_FORM_data8:
86 /*
87 * DW_FORM_data[48] can not be used as section offset
88 * since DWARF4. For DWARF[23], the application needs
89 * to determine if DW_FORM_data[48] is representing
90 * a constant or a section offset.
91 */
92 if (at->at_die->die_cu->cu_version >= 4) {
93 DWARF_SET_ERROR(dbg, error, DW_DLE_NO_ENTRY);
94 return (DW_DLV_NO_ENTRY);
95 }
96 /* FALLTHROUGH */
97 case DW_FORM_sec_offset:
98 ret = _dwarf_loclist_find(dbg, at->at_die->die_cu,
99 at->u[0].u64, llbuf, listlen, NULL, error);
100 if (ret == DW_DLE_NO_ENTRY) {
101 DWARF_SET_ERROR(dbg, error, ret);
102 return (DW_DLV_NO_ENTRY);
103 }
104 if (ret != DW_DLE_NONE)
105 return (DW_DLV_ERROR);
106 return (DW_DLV_OK);
107 case DW_FORM_block:
108 case DW_FORM_block1:
109 case DW_FORM_block2:
110 case DW_FORM_block4:
111 case DW_FORM_exprloc:
112 if (at->at_ld == NULL) {
113 ret = _dwarf_loc_add(at->at_die, at, error);
114 if (ret != DW_DLE_NONE)
115 return (DW_DLV_ERROR);
116 }
117 *llbuf = calloc(1, sizeof(Dwarf_Locdesc *));
118 if (*llbuf == NULL) {
119 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
120 return (DW_DLV_ERROR);
121 }
122 (*llbuf)[0] = calloc(1, sizeof(Dwarf_Locdesc));
123 if ((*llbuf)[0] == NULL) {
124 free(*llbuf);
125 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
126 return (DW_DLV_ERROR);
127 }
128 if (copy_locdesc(dbg, (*llbuf)[0], at->at_ld, error) !=
129 DW_DLE_NONE) {
130 free((*llbuf)[0]);
131 free(*llbuf);
132 return (DW_DLV_ERROR);
133 }
134 *listlen = 1;
135 return (DW_DLV_OK);
136 default:
137 /* Malformed Attr? */
138 DWARF_SET_ERROR(dbg, error, DW_DLE_ATTR_FORM_BAD);
139 return (DW_DLV_NO_ENTRY);
140 }
141 default:
142 /* Wrong attr supplied. */
143 DWARF_SET_ERROR(dbg, error, DW_DLE_ARGUMENT);
144 return (DW_DLV_ERROR);
145 }
146 }
147
148 int
dwarf_loclist(Dwarf_Attribute at,Dwarf_Locdesc ** llbuf,Dwarf_Signed * listlen,Dwarf_Error * error)149 dwarf_loclist(Dwarf_Attribute at, Dwarf_Locdesc **llbuf,
150 Dwarf_Signed *listlen, Dwarf_Error *error)
151 {
152 Dwarf_Locdesc **_llbuf;
153 int i, ret;
154
155 ret = dwarf_loclist_n(at, &_llbuf, listlen, error);
156 if (ret != DW_DLV_OK)
157 return (ret);
158
159 /* Only return the first location description of the list. */
160 *llbuf = _llbuf[0];
161
162 /* Free the rest of the list. */
163 for (i = 1; i < *listlen; i++) {
164 if (_llbuf[i]->ld_s)
165 free(_llbuf[i]->ld_s);
166 free(_llbuf[i]);
167 }
168 free(_llbuf);
169
170 *listlen = 1;
171
172 return (DW_DLV_OK);
173 }
174
175 int
dwarf_get_loclist_entry(Dwarf_Debug dbg,Dwarf_Unsigned offset,Dwarf_Addr * hipc,Dwarf_Addr * lopc,Dwarf_Ptr * data,Dwarf_Unsigned * entry_len,Dwarf_Unsigned * next_entry,Dwarf_Error * error)176 dwarf_get_loclist_entry(Dwarf_Debug dbg, Dwarf_Unsigned offset,
177 Dwarf_Addr *hipc, Dwarf_Addr *lopc, Dwarf_Ptr *data,
178 Dwarf_Unsigned *entry_len, Dwarf_Unsigned *next_entry,
179 Dwarf_Error *error)
180 {
181 Dwarf_Locdesc *ld, **llbuf;
182 Dwarf_Section *ds;
183 Dwarf_Signed listlen;
184 int i, ret;
185
186 /*
187 * Note that this API sometimes will not work correctly because
188 * it assumes that all units have the same pointer size and offset
189 * size.
190 */
191
192 if (dbg == NULL || hipc == NULL || lopc == NULL || data == NULL ||
193 entry_len == NULL || next_entry == NULL) {
194 DWARF_SET_ERROR(dbg, error, DW_DLE_ARGUMENT);
195 return (DW_DLV_ERROR);
196 }
197
198 ret = _dwarf_loclist_find(dbg, STAILQ_FIRST(&dbg->dbg_cu), offset,
199 &llbuf, &listlen, entry_len, error);
200 if (ret == DW_DLE_NO_ENTRY) {
201 DWARF_SET_ERROR(dbg, error, DW_DLV_NO_ENTRY);
202 return (DW_DLV_NO_ENTRY);
203 } else if (ret != DW_DLE_NONE)
204 return (DW_DLV_ERROR);
205
206 *hipc = *lopc = 0;
207 for (i = 0; i < listlen; i++) {
208 ld = llbuf[i];
209 if (i == 0) {
210 *hipc = ld->ld_hipc;
211 *lopc = ld->ld_lopc;
212 } else {
213 if (ld->ld_lopc < *lopc)
214 *lopc = ld->ld_lopc;
215 if (ld->ld_hipc > *hipc)
216 *hipc = ld->ld_hipc;
217 }
218 }
219
220 ds = _dwarf_find_section(dbg, ".debug_loc");
221 assert(ds != NULL);
222 *data = (uint8_t *) ds->ds_data + offset;
223 *next_entry = offset + *entry_len;
224
225 return (DW_DLV_OK);
226 }
227
228 int
dwarf_loclist_from_expr(Dwarf_Debug dbg,Dwarf_Ptr bytes_in,Dwarf_Unsigned bytes_len,Dwarf_Locdesc ** llbuf,Dwarf_Signed * listlen,Dwarf_Error * error)229 dwarf_loclist_from_expr(Dwarf_Debug dbg, Dwarf_Ptr bytes_in,
230 Dwarf_Unsigned bytes_len, Dwarf_Locdesc **llbuf, Dwarf_Signed *listlen,
231 Dwarf_Error *error)
232 {
233
234 return (dwarf_loclist_from_expr_a(dbg, bytes_in, bytes_len,
235 dbg->dbg_pointer_size, llbuf, listlen, error));
236 }
237
238 int
dwarf_loclist_from_expr_a(Dwarf_Debug dbg,Dwarf_Ptr bytes_in,Dwarf_Unsigned bytes_len,Dwarf_Half addr_size,Dwarf_Locdesc ** llbuf,Dwarf_Signed * listlen,Dwarf_Error * error)239 dwarf_loclist_from_expr_a(Dwarf_Debug dbg, Dwarf_Ptr bytes_in,
240 Dwarf_Unsigned bytes_len, Dwarf_Half addr_size, Dwarf_Locdesc **llbuf,
241 Dwarf_Signed *listlen, Dwarf_Error *error)
242 {
243 Dwarf_Half offset_size;
244 Dwarf_Small version;
245
246 /*
247 * Obtain offset size and DWARF version from the current
248 * Compilation Unit or Type Unit. These values are needed
249 * for correctly parsing DW_OP_GNU_implicit_pointer operator.
250 *
251 * Note that dwarf_loclist_from_expr_b() should be used instead
252 * if the application knows correct values for offset size
253 * and DWARF version.
254 */
255 if (dbg->dbg_cu_current) {
256 offset_size = dbg->dbg_cu_current->cu_length_size == 4 ? 4 : 8;
257 version = dbg->dbg_cu_current->cu_version;
258 } else if (dbg->dbg_tu_current) {
259 offset_size = dbg->dbg_tu_current->cu_length_size == 4 ? 4 : 8;
260 version = dbg->dbg_tu_current->cu_version;
261 } else {
262 /* Default values if no CU/TU context. */
263 offset_size = 4;
264 version = 2; /* DWARF2 */
265 }
266
267 return (dwarf_loclist_from_expr_b(dbg, bytes_in, bytes_len, addr_size,
268 offset_size, version, llbuf, listlen, error));
269 }
270
271 int
dwarf_loclist_from_expr_b(Dwarf_Debug dbg,Dwarf_Ptr bytes_in,Dwarf_Unsigned bytes_len,Dwarf_Half addr_size,Dwarf_Half offset_size,Dwarf_Small version,Dwarf_Locdesc ** llbuf,Dwarf_Signed * listlen,Dwarf_Error * error)272 dwarf_loclist_from_expr_b(Dwarf_Debug dbg, Dwarf_Ptr bytes_in,
273 Dwarf_Unsigned bytes_len, Dwarf_Half addr_size, Dwarf_Half offset_size,
274 Dwarf_Small version, Dwarf_Locdesc **llbuf, Dwarf_Signed *listlen,
275 Dwarf_Error *error)
276 {
277 Dwarf_Locdesc *ld;
278 int ret;
279
280 if (dbg == NULL || bytes_in == NULL || bytes_len == 0 ||
281 llbuf == NULL || listlen == NULL) {
282 DWARF_SET_ERROR(dbg, error, DW_DLE_ARGUMENT);
283 return (DW_DLV_ERROR);
284 }
285
286 if (addr_size != 4 && addr_size != 8) {
287 DWARF_SET_ERROR(dbg, error, DW_DLE_ARGUMENT);
288 return (DW_DLV_ERROR);
289 }
290
291 if (offset_size != 4 && offset_size != 8) {
292 DWARF_SET_ERROR(dbg, error, DW_DLE_ARGUMENT);
293 return (DW_DLV_ERROR);
294 }
295
296 ret = _dwarf_loc_fill_locexpr(dbg, &ld, bytes_in, bytes_len, addr_size,
297 offset_size, version, error);
298 if (ret != DW_DLE_NONE)
299 return (DW_DLV_ERROR);
300
301 *llbuf = ld;
302 *listlen = 1;
303
304 return (DW_DLV_OK);
305 }
306