1 /* rddbg.c -- Read debugging information into a generic form.
2 Copyright (C) 1995-2022 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 *
read_debugging_info(bfd * abfd,asymbol ** syms,long symcount,bool no_messages)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 ();
53 if (dhandle == NULL)
54 return NULL;
55
56 if (! read_section_stabs_debugging_info (abfd, syms, symcount, dhandle,
57 &found))
58 goto err_exit;
59
60 if (bfd_get_flavour (abfd) == bfd_target_aout_flavour)
61 {
62 if (! read_symbol_stabs_debugging_info (abfd, syms, symcount, dhandle,
63 &found))
64 goto err_exit;
65 }
66
67 /* Try reading the COFF symbols if we didn't find any stabs in COFF
68 sections. */
69 if (! found
70 && bfd_get_flavour (abfd) == bfd_target_coff_flavour
71 && symcount > 0)
72 {
73 if (! parse_coff (abfd, syms, symcount, dhandle))
74 goto err_exit;
75 found = true;
76 }
77
78 if (! found)
79 {
80 if (! no_messages)
81 non_fatal (_("%s: no recognized debugging information"),
82 bfd_get_filename (abfd));
83 err_exit:
84 free (dhandle);
85 return NULL;
86 }
87
88 return dhandle;
89 }
90
91 /* Read stabs in sections debugging information from a BFD. */
92
93 static bool
read_section_stabs_debugging_info(bfd * abfd,asymbol ** syms,long symcount,void * dhandle,bool * pfound)94 read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
95 void *dhandle, bool *pfound)
96 {
97 static struct
98 {
99 const char *secname;
100 const char *strsecname;
101 }
102 names[] =
103 {
104 { ".stab", ".stabstr" },
105 { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" },
106 { "$GDB_SYMBOLS$", "$GDB_STRINGS$" }
107 };
108 unsigned int i;
109 void *shandle;
110
111 *pfound = false;
112 shandle = NULL;
113
114 for (i = 0; i < sizeof names / sizeof names[0]; i++)
115 {
116 asection *sec, *strsec;
117
118 sec = bfd_get_section_by_name (abfd, names[i].secname);
119 strsec = bfd_get_section_by_name (abfd, names[i].strsecname);
120 if (sec != NULL && strsec != NULL)
121 {
122 bfd_size_type stabsize, strsize;
123 bfd_byte *stabs, *strings;
124 bfd_byte *stab;
125 bfd_size_type stroff, next_stroff;
126
127 stabsize = bfd_section_size (sec);
128 stabs = (bfd_byte *) xmalloc (stabsize);
129 if (! bfd_get_section_contents (abfd, sec, stabs, 0, stabsize))
130 {
131 fprintf (stderr, "%s: %s: %s\n",
132 bfd_get_filename (abfd), names[i].secname,
133 bfd_errmsg (bfd_get_error ()));
134 free (shandle);
135 free (stabs);
136 return false;
137 }
138
139 strsize = bfd_section_size (strsec);
140 strings = (bfd_byte *) xmalloc (strsize + 1);
141 if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize))
142 {
143 fprintf (stderr, "%s: %s: %s\n",
144 bfd_get_filename (abfd), names[i].strsecname,
145 bfd_errmsg (bfd_get_error ()));
146 free (shandle);
147 free (strings);
148 free (stabs);
149 return false;
150 }
151 /* Zero terminate the strings table, just in case. */
152 strings [strsize] = 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 return false;
161 }
162 }
163
164 *pfound = true;
165
166 stroff = 0;
167 next_stroff = 0;
168 /* PR 17512: file: 078-60391-0.001:0.1. */
169 for (stab = stabs; stab <= (stabs + stabsize) - 12; stab += 12)
170 {
171 unsigned int strx;
172 int type;
173 int other ATTRIBUTE_UNUSED;
174 int desc;
175 bfd_vma value;
176
177 /* This code presumes 32 bit values. */
178
179 strx = bfd_get_32 (abfd, stab);
180 type = bfd_get_8 (abfd, stab + 4);
181 other = bfd_get_8 (abfd, stab + 5);
182 desc = bfd_get_16 (abfd, stab + 6);
183 value = bfd_get_32 (abfd, stab + 8);
184
185 if (type == 0)
186 {
187 /* Special type 0 stabs indicate the offset to the
188 next string table. */
189 stroff = next_stroff;
190 next_stroff += value;
191 }
192 else
193 {
194 size_t len;
195 char *f, *s;
196
197 if (stroff + strx >= strsize)
198 {
199 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n"),
200 bfd_get_filename (abfd), names[i].secname,
201 (long) (stab - stabs) / 12, strx, type);
202 continue;
203 }
204
205 s = (char *) strings + stroff + strx;
206 f = NULL;
207
208 /* PR 17512: file: 002-87578-0.001:0.1.
209 It is possible to craft a file where, without the 'strlen (s) > 0',
210 an attempt to read the byte before 'strings' would occur. */
211 while ((len = strlen (s)) > 0
212 && s[len - 1] == '\\'
213 && stab + 16 <= stabs + stabsize)
214 {
215 char *p;
216
217 stab += 12;
218 p = s + len - 1;
219 *p = '\0';
220 strx = stroff + bfd_get_32 (abfd, stab);
221 if (strx >= strsize)
222 {
223 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt\n"),
224 bfd_get_filename (abfd), names[i].secname,
225 (long) (stab - stabs) / 12);
226 break;
227 }
228
229 s = concat (s, (char *) strings + strx,
230 (const char *) NULL);
231
232 /* We have to restore the backslash, because, if
233 the linker is hashing stabs strings, we may
234 see the same string more than once. */
235 *p = '\\';
236
237 free (f);
238 f = s;
239 }
240
241 save_stab (type, desc, value, s);
242
243 if (! parse_stab (dhandle, shandle, type, desc, value, s))
244 {
245 stab_context ();
246 free_saved_stabs ();
247 free (f);
248 free (shandle);
249 free (stabs);
250 free (strings);
251 return false;
252 }
253
254 /* Don't free f, since I think the stabs code
255 expects strings to hang around. This should be
256 straightened out. FIXME. */
257 }
258 }
259
260 free_saved_stabs ();
261 free (stabs);
262
263 /* Don't free strings, since I think the stabs code expects
264 the strings to hang around. This should be straightened
265 out. FIXME. */
266 }
267 }
268
269 if (shandle != NULL)
270 {
271 if (! finish_stab (dhandle, shandle))
272 return false;
273 }
274
275 return true;
276 }
277
278 /* Read stabs in the symbol table. */
279
280 static bool
read_symbol_stabs_debugging_info(bfd * abfd,asymbol ** syms,long symcount,void * dhandle,bool * pfound)281 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
282 void *dhandle, bool *pfound)
283 {
284 void *shandle;
285 asymbol **ps, **symend;
286
287 shandle = NULL;
288 symend = syms + symcount;
289 for (ps = syms; ps < symend; ps++)
290 {
291 symbol_info i;
292
293 bfd_get_symbol_info (abfd, *ps, &i);
294
295 if (i.type == '-')
296 {
297 const char *s;
298 char *f;
299
300 if (shandle == NULL)
301 {
302 shandle = start_stab (dhandle, abfd, false, syms, symcount);
303 if (shandle == NULL)
304 return false;
305 }
306
307 *pfound = true;
308
309 s = i.name;
310 if (s == NULL || strlen (s) < 1)
311 return false;
312 f = NULL;
313
314 while (strlen (s) > 0
315 && s[strlen (s) - 1] == '\\'
316 && ps + 1 < symend)
317 {
318 char *sc, *n;
319
320 ++ps;
321 sc = xstrdup (s);
322 sc[strlen (sc) - 1] = '\0';
323 n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
324 free (sc);
325 free (f);
326 f = n;
327 s = n;
328 }
329
330 save_stab (i.stab_type, i.stab_desc, i.value, s);
331
332 if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
333 i.value, s))
334 {
335 stab_context ();
336 free_saved_stabs ();
337 return false;
338 }
339
340 /* Don't free f, since I think the stabs code expects
341 strings to hang around. This should be straightened out.
342 FIXME. */
343 }
344 }
345
346 free_saved_stabs ();
347
348 if (shandle != NULL)
349 {
350 if (! finish_stab (dhandle, shandle))
351 return false;
352 }
353
354 return true;
355 }
356
357 /* Record stabs strings, so that we can give some context for errors. */
358
359 #define SAVE_STABS_COUNT (16)
360
361 struct saved_stab
362 {
363 int type;
364 int desc;
365 bfd_vma value;
366 char *string;
367 };
368
369 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
370 static int saved_stabs_index;
371
372 /* Save a stabs string. */
373
374 static void
save_stab(int type,int desc,bfd_vma value,const char * string)375 save_stab (int type, int desc, bfd_vma value, const char *string)
376 {
377 free (saved_stabs[saved_stabs_index].string);
378 saved_stabs[saved_stabs_index].type = type;
379 saved_stabs[saved_stabs_index].desc = desc;
380 saved_stabs[saved_stabs_index].value = value;
381 saved_stabs[saved_stabs_index].string = xstrdup (string);
382 saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
383 }
384
385 /* Provide context for an error. */
386
387 static void
stab_context(void)388 stab_context (void)
389 {
390 int i;
391
392 fprintf (stderr, _("Last stabs entries before error:\n"));
393 fprintf (stderr, "n_type n_desc n_value string\n");
394
395 i = saved_stabs_index;
396 do
397 {
398 struct saved_stab *stabp;
399
400 stabp = saved_stabs + i;
401 if (stabp->string != NULL)
402 {
403 const char *s;
404
405 s = bfd_get_stab_name (stabp->type);
406 if (s != NULL)
407 fprintf (stderr, "%-6s", s);
408 else if (stabp->type == 0)
409 fprintf (stderr, "HdrSym");
410 else
411 fprintf (stderr, "%-6d", stabp->type);
412 fprintf (stderr, " %-6d ", stabp->desc);
413 fprintf_vma (stderr, stabp->value);
414 if (stabp->type != 0)
415 fprintf (stderr, " %s", stabp->string);
416 fprintf (stderr, "\n");
417 }
418 i = (i + 1) % SAVE_STABS_COUNT;
419 }
420 while (i != saved_stabs_index);
421 }
422
423 /* Free the saved stab strings. */
424
425 static void
free_saved_stabs(void)426 free_saved_stabs (void)
427 {
428 int i;
429
430 for (i = 0; i < SAVE_STABS_COUNT; i++)
431 {
432 free (saved_stabs[i].string);
433 saved_stabs[i].string = NULL;
434 }
435
436 saved_stabs_index = 0;
437 }
438