1 /* rddbg.c -- Read debugging information into a generic form.
2 Copyright (C) 1995-2023 Free Software Foundation, Inc.
3 Written by Ian Lance Taylor <ian@cygnus.com>.
4
5 This file is part of GNU Binutils.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
20 02110-1301, USA. */
21
22
23 /* This file reads debugging information into a generic form. This
24 file knows how to dig the debugging information out of an object
25 file. */
26
27 #include "sysdep.h"
28 #include "bfd.h"
29 #include "libiberty.h"
30 #include "bucomm.h"
31 #include "debug.h"
32 #include "budbg.h"
33
34 static bool read_section_stabs_debugging_info
35 (bfd *, asymbol **, long, void *, bool *);
36 static bool read_symbol_stabs_debugging_info
37 (bfd *, asymbol **, long, void *, bool *);
38 static void save_stab (int, int, bfd_vma, const char *);
39 static void stab_context (void);
40 static void free_saved_stabs (void);
41
42 /* Read debugging information from a BFD. Returns a generic debugging
43 pointer. */
44
45 void *
46 read_debugging_info (bfd *abfd, asymbol **syms, long symcount,
47 bool no_messages)
48 {
49 void *dhandle;
50 bool found;
51
52 dhandle = debug_init (abfd);
53 if (dhandle == NULL)
54 return NULL;
55
56 if (!debug_set_filename (dhandle, bfd_get_filename (abfd)))
57 return NULL;
58
59 if (! read_section_stabs_debugging_info (abfd, syms, symcount, dhandle,
60 &found))
61 return NULL;
62
63 if (bfd_get_flavour (abfd) == bfd_target_aout_flavour)
64 {
65 if (! read_symbol_stabs_debugging_info (abfd, syms, symcount, dhandle,
66 &found))
67 return NULL;
68 }
69
70 /* Try reading the COFF symbols if we didn't find any stabs in COFF
71 sections. */
72 if (! found
73 && bfd_get_flavour (abfd) == bfd_target_coff_flavour
74 && symcount > 0)
75 {
76 if (! parse_coff (abfd, syms, symcount, dhandle))
77 return NULL;
78 found = true;
79 }
80
81 if (! found)
82 {
83 if (! no_messages)
84 non_fatal (_("%s: no recognized debugging information"),
85 bfd_get_filename (abfd));
86 return NULL;
87 }
88
89 return dhandle;
90 }
91
92 /* Read stabs in sections debugging information from a BFD. */
93
94 static bool
95 read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
96 void *dhandle, bool *pfound)
97 {
98 static struct
99 {
100 const char *secname;
101 const char *strsecname;
102 }
103 names[] =
104 {
105 { ".stab", ".stabstr" },
106 { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" },
107 { "$GDB_SYMBOLS$", "$GDB_STRINGS$" }
108 };
109 unsigned int i;
110 void *shandle;
111 bool ret = false;
112
113 *pfound = false;
114 shandle = NULL;
115
116 for (i = 0; i < sizeof names / sizeof names[0]; i++)
117 {
118 asection *sec, *strsec;
119
120 sec = bfd_get_section_by_name (abfd, names[i].secname);
121 strsec = bfd_get_section_by_name (abfd, names[i].strsecname);
122 if (sec != NULL
123 && (bfd_section_flags (sec) & SEC_HAS_CONTENTS) != 0
124 && bfd_section_size (sec) >= 12
125 && strsec != NULL
126 && (bfd_section_flags (strsec) & SEC_HAS_CONTENTS) != 0)
127 {
128 bfd_size_type stabsize, strsize;
129 bfd_byte *stabs, *strings;
130 bfd_byte *stab;
131 bfd_size_type stroff, next_stroff;
132
133 if (!bfd_malloc_and_get_section (abfd, sec, &stabs))
134 {
135 fprintf (stderr, "%s: %s: %s\n",
136 bfd_get_filename (abfd), names[i].secname,
137 bfd_errmsg (bfd_get_error ()));
138 goto out;
139 }
140
141 if (!bfd_malloc_and_get_section (abfd, strsec, &strings))
142 {
143 fprintf (stderr, "%s: %s: %s\n",
144 bfd_get_filename (abfd), names[i].strsecname,
145 bfd_errmsg (bfd_get_error ()));
146 free (stabs);
147 goto out;
148 }
149 /* Zero terminate the strings table, just in case. */
150 strsize = bfd_section_size (strsec);
151 if (strsize != 0)
152 strings [strsize - 1] = 0;
153 if (shandle == NULL)
154 {
155 shandle = start_stab (dhandle, abfd, true, syms, symcount);
156 if (shandle == NULL)
157 {
158 free (strings);
159 free (stabs);
160 goto out;
161 }
162 }
163
164 *pfound = true;
165
166 stroff = 0;
167 next_stroff = 0;
168 stabsize = bfd_section_size (sec);
169 /* PR 17512: file: 078-60391-0.001:0.1. */
170 for (stab = stabs; stab <= (stabs + stabsize) - 12; stab += 12)
171 {
172 unsigned int strx;
173 int type;
174 int other ATTRIBUTE_UNUSED;
175 int desc;
176 bfd_vma value;
177
178 /* This code presumes 32 bit values. */
179
180 strx = bfd_get_32 (abfd, stab);
181 type = bfd_get_8 (abfd, stab + 4);
182 other = bfd_get_8 (abfd, stab + 5);
183 desc = bfd_get_16 (abfd, stab + 6);
184 value = bfd_get_32 (abfd, stab + 8);
185
186 if (type == 0)
187 {
188 /* Special type 0 stabs indicate the offset to the
189 next string table. */
190 stroff = next_stroff;
191 next_stroff += value;
192 }
193 else
194 {
195 size_t len;
196 char *f, *s;
197
198 if (stroff + strx >= strsize)
199 {
200 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n"),
201 bfd_get_filename (abfd), names[i].secname,
202 (long) (stab - stabs) / 12, strx, type);
203 continue;
204 }
205
206 s = (char *) strings + stroff + strx;
207 f = NULL;
208
209 /* PR 17512: file: 002-87578-0.001:0.1.
210 It is possible to craft a file where, without the 'strlen (s) > 0',
211 an attempt to read the byte before 'strings' would occur. */
212 while ((len = strlen (s)) > 0
213 && s[len - 1] == '\\'
214 && stab + 16 <= stabs + stabsize)
215 {
216 char *p;
217
218 stab += 12;
219 p = s + len - 1;
220 *p = '\0';
221 strx = stroff + bfd_get_32 (abfd, stab);
222 if (strx >= strsize)
223 {
224 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt\n"),
225 bfd_get_filename (abfd), names[i].secname,
226 (long) (stab - stabs) / 12);
227 break;
228 }
229
230 s = concat (s, (char *) strings + strx,
231 (const char *) NULL);
232
233 /* We have to restore the backslash, because, if
234 the linker is hashing stabs strings, we may
235 see the same string more than once. */
236 *p = '\\';
237
238 free (f);
239 f = s;
240 }
241
242 save_stab (type, desc, value, s);
243
244 if (!parse_stab (dhandle, shandle, type, desc, value, s))
245 {
246 stab_context ();
247 free_saved_stabs ();
248 free (f);
249 free (stabs);
250 free (strings);
251 goto out;
252 }
253
254 free (f);
255 }
256 }
257
258 free_saved_stabs ();
259 free (stabs);
260 free (strings);
261 }
262 }
263 ret = true;
264
265 out:
266 if (shandle != NULL)
267 {
268 if (! finish_stab (dhandle, shandle, ret))
269 return false;
270 }
271
272 return ret;
273 }
274
275 /* Read stabs in the symbol table. */
276
277 static bool
278 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
279 void *dhandle, bool *pfound)
280 {
281 void *shandle;
282 asymbol **ps, **symend;
283
284 shandle = NULL;
285 symend = syms + symcount;
286 for (ps = syms; ps < symend; ps++)
287 {
288 symbol_info i;
289
290 bfd_get_symbol_info (abfd, *ps, &i);
291
292 if (i.type == '-')
293 {
294 const char *s;
295 char *f;
296
297 if (shandle == NULL)
298 {
299 shandle = start_stab (dhandle, abfd, false, syms, symcount);
300 if (shandle == NULL)
301 return false;
302 }
303
304 *pfound = true;
305
306 s = i.name;
307 if (s == NULL || strlen (s) < 1)
308 break;
309 f = NULL;
310
311 while (strlen (s) > 0
312 && s[strlen (s) - 1] == '\\'
313 && ps + 1 < symend)
314 {
315 char *sc, *n;
316
317 ++ps;
318 sc = xstrdup (s);
319 sc[strlen (sc) - 1] = '\0';
320 n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
321 free (sc);
322 free (f);
323 f = n;
324 s = n;
325 }
326
327 save_stab (i.stab_type, i.stab_desc, i.value, s);
328
329 if (!parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
330 i.value, s))
331 {
332 stab_context ();
333 free (f);
334 break;
335 }
336
337 free (f);
338 }
339 }
340 bool ret = ps >= symend;
341
342 free_saved_stabs ();
343
344 if (shandle != NULL)
345 {
346 if (! finish_stab (dhandle, shandle, ret))
347 return false;
348 }
349
350 return ret;
351 }
352
353 /* Record stabs strings, so that we can give some context for errors. */
354
355 #define SAVE_STABS_COUNT (16)
356
357 struct saved_stab
358 {
359 int type;
360 int desc;
361 bfd_vma value;
362 char *string;
363 };
364
365 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
366 static int saved_stabs_index;
367
368 /* Save a stabs string. */
369
370 static void
371 save_stab (int type, int desc, bfd_vma value, const char *string)
372 {
373 free (saved_stabs[saved_stabs_index].string);
374 saved_stabs[saved_stabs_index].type = type;
375 saved_stabs[saved_stabs_index].desc = desc;
376 saved_stabs[saved_stabs_index].value = value;
377 saved_stabs[saved_stabs_index].string = xstrdup (string);
378 saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
379 }
380
381 /* Provide context for an error. */
382
383 static void
384 stab_context (void)
385 {
386 int i;
387
388 fprintf (stderr, _("Last stabs entries before error:\n"));
389 fprintf (stderr, "n_type n_desc n_value string\n");
390
391 i = saved_stabs_index;
392 do
393 {
394 struct saved_stab *stabp;
395
396 stabp = saved_stabs + i;
397 if (stabp->string != NULL)
398 {
399 const char *s;
400
401 s = bfd_get_stab_name (stabp->type);
402 if (s != NULL)
403 fprintf (stderr, "%-6s", s);
404 else if (stabp->type == 0)
405 fprintf (stderr, "HdrSym");
406 else
407 fprintf (stderr, "%-6d", stabp->type);
408 fprintf (stderr, " %-6d ", stabp->desc);
409 fprintf (stderr, "%08" PRIx64, (uint64_t) stabp->value);
410 if (stabp->type != 0)
411 fprintf (stderr, " %s", stabp->string);
412 fprintf (stderr, "\n");
413 }
414 i = (i + 1) % SAVE_STABS_COUNT;
415 }
416 while (i != saved_stabs_index);
417 }
418
419 /* Free the saved stab strings. */
420
421 static void
422 free_saved_stabs (void)
423 {
424 int i;
425
426 for (i = 0; i < SAVE_STABS_COUNT; i++)
427 {
428 free (saved_stabs[i].string);
429 saved_stabs[i].string = NULL;
430 }
431
432 saved_stabs_index = 0;
433 }