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13437d4b | 1 | /* Handle SunOS and SVR4 shared libraries for GDB, the GNU Debugger. |
b6ba6518 KB |
2 | Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, |
3 | 2001 | |
13437d4b KB |
4 | Free Software Foundation, Inc. |
5 | ||
6 | This file is part of GDB. | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program; if not, write to the Free Software | |
20 | Foundation, Inc., 59 Temple Place - Suite 330, | |
21 | Boston, MA 02111-1307, USA. */ | |
22 | ||
13437d4b | 23 | #include "defs.h" |
4e052eda | 24 | #include "regcache.h" |
13437d4b KB |
25 | |
26 | ||
27 | #include <sys/types.h> | |
28 | #include <signal.h> | |
29 | #include "gdb_string.h" | |
30 | #include <sys/param.h> | |
31 | #include <fcntl.h> | |
32 | ||
33 | #ifndef SVR4_SHARED_LIBS | |
34 | /* SunOS shared libs need the nlist structure. */ | |
35 | #include <a.out.h> | |
21479ded | 36 | #include <link.h> |
13437d4b KB |
37 | #else |
38 | #include "elf/external.h" | |
21479ded | 39 | #include "elf/common.h" |
13437d4b KB |
40 | #endif |
41 | ||
42 | #include "symtab.h" | |
43 | #include "bfd.h" | |
44 | #include "symfile.h" | |
45 | #include "objfiles.h" | |
46 | #include "gdbcore.h" | |
47 | #include "command.h" | |
48 | #include "target.h" | |
49 | #include "frame.h" | |
50 | #include "gdb_regex.h" | |
51 | #include "inferior.h" | |
52 | #include "environ.h" | |
53 | #include "language.h" | |
54 | #include "gdbcmd.h" | |
55 | ||
56 | #include "solist.h" | |
57 | #include "solib-svr4.h" | |
58 | ||
21479ded KB |
59 | #ifndef SVR4_FETCH_LINK_MAP_OFFSETS |
60 | #define SVR4_FETCH_LINK_MAP_OFFSETS() fetch_link_map_offsets () | |
61 | #endif | |
62 | ||
63 | static struct link_map_offsets *default_svr4_fetch_link_map_offsets (void); | |
64 | static struct link_map_offsets *(*fetch_link_map_offsets)(void) = | |
65 | default_svr4_fetch_link_map_offsets; | |
66 | ||
67 | /* legacy_svr4_fetch_link_map_offsets_hook is a pointer to a function | |
68 | which is used to fetch link map offsets. It will only be set | |
69 | by solib-legacy.c, if at all. */ | |
70 | struct link_map_offsets *(*legacy_svr4_fetch_link_map_offsets_hook)(void) = 0; | |
71 | ||
13437d4b KB |
72 | /* Link map info to include in an allocated so_list entry */ |
73 | ||
74 | struct lm_info | |
75 | { | |
76 | /* Pointer to copy of link map from inferior. The type is char * | |
77 | rather than void *, so that we may use byte offsets to find the | |
78 | various fields without the need for a cast. */ | |
79 | char *lm; | |
80 | }; | |
81 | ||
82 | /* On SVR4 systems, a list of symbols in the dynamic linker where | |
83 | GDB can try to place a breakpoint to monitor shared library | |
84 | events. | |
85 | ||
86 | If none of these symbols are found, or other errors occur, then | |
87 | SVR4 systems will fall back to using a symbol as the "startup | |
88 | mapping complete" breakpoint address. */ | |
89 | ||
90 | #ifdef SVR4_SHARED_LIBS | |
91 | static char *solib_break_names[] = | |
92 | { | |
93 | "r_debug_state", | |
94 | "_r_debug_state", | |
95 | "_dl_debug_state", | |
96 | "rtld_db_dlactivity", | |
1f72e589 | 97 | "_rtld_debug_state", |
13437d4b KB |
98 | NULL |
99 | }; | |
100 | #endif | |
101 | ||
102 | #define BKPT_AT_SYMBOL 1 | |
103 | ||
104 | #if defined (BKPT_AT_SYMBOL) && defined (SVR4_SHARED_LIBS) | |
105 | static char *bkpt_names[] = | |
106 | { | |
107 | #ifdef SOLIB_BKPT_NAME | |
108 | SOLIB_BKPT_NAME, /* Prefer configured name if it exists. */ | |
109 | #endif | |
110 | "_start", | |
111 | "main", | |
112 | NULL | |
113 | }; | |
114 | #endif | |
115 | ||
116 | /* Symbols which are used to locate the base of the link map structures. */ | |
117 | ||
118 | #ifndef SVR4_SHARED_LIBS | |
119 | static char *debug_base_symbols[] = | |
120 | { | |
121 | "_DYNAMIC", | |
122 | "_DYNAMIC__MGC", | |
123 | NULL | |
124 | }; | |
125 | #endif | |
126 | ||
127 | static char *main_name_list[] = | |
128 | { | |
129 | "main_$main", | |
130 | NULL | |
131 | }; | |
132 | ||
133 | ||
134 | /* Fetch (and possibly build) an appropriate link_map_offsets structure | |
21479ded KB |
135 | for native targets using struct definitions from link.h. |
136 | ||
137 | Note: For non-native targets (i.e. cross-debugging situations), | |
138 | you need to define a target specific fetch_link_map_offsets() | |
139 | function and call set_solib_svr4_fetch_link_map_offsets () to | |
140 | register this function. */ | |
13437d4b | 141 | |
21479ded | 142 | static struct link_map_offsets * |
13437d4b KB |
143 | default_svr4_fetch_link_map_offsets (void) |
144 | { | |
21479ded KB |
145 | if (legacy_svr4_fetch_link_map_offsets_hook) |
146 | return legacy_svr4_fetch_link_map_offsets_hook (); | |
147 | else | |
13437d4b | 148 | { |
21479ded KB |
149 | internal_error (__FILE__, __LINE__, |
150 | "default_svr4_fetch_link_map_offsets called without legacy link_map support enabled."); | |
151 | return 0; | |
13437d4b | 152 | } |
13437d4b KB |
153 | } |
154 | ||
155 | /* Macro to extract an address from a solib structure. | |
156 | When GDB is configured for some 32-bit targets (e.g. Solaris 2.7 | |
157 | sparc), BFD is configured to handle 64-bit targets, so CORE_ADDR is | |
158 | 64 bits. We have to extract only the significant bits of addresses | |
159 | to get the right address when accessing the core file BFD. */ | |
160 | ||
161 | #define SOLIB_EXTRACT_ADDRESS(MEMBER) \ | |
162 | extract_address (&(MEMBER), sizeof (MEMBER)) | |
163 | ||
164 | /* local data declarations */ | |
165 | ||
166 | #ifndef SVR4_SHARED_LIBS | |
167 | ||
168 | /* NOTE: converted the macros LM_ADDR, LM_NEXT, LM_NAME and | |
169 | IGNORE_FIRST_LINK_MAP_ENTRY into functions (see below). | |
170 | MVS, June 2000 */ | |
171 | ||
172 | static struct link_dynamic dynamic_copy; | |
173 | static struct link_dynamic_2 ld_2_copy; | |
174 | static struct ld_debug debug_copy; | |
175 | static CORE_ADDR debug_addr; | |
176 | static CORE_ADDR flag_addr; | |
177 | ||
178 | #endif /* !SVR4_SHARED_LIBS */ | |
179 | ||
180 | /* link map access functions */ | |
181 | ||
182 | static CORE_ADDR | |
183 | LM_ADDR (struct so_list *so) | |
184 | { | |
185 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
186 | ||
58bc91c9 MH |
187 | return (CORE_ADDR) extract_signed_integer (so->lm_info->lm + lmo->l_addr_offset, |
188 | lmo->l_addr_size); | |
13437d4b KB |
189 | } |
190 | ||
191 | static CORE_ADDR | |
192 | LM_NEXT (struct so_list *so) | |
193 | { | |
194 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
195 | ||
196 | return extract_address (so->lm_info->lm + lmo->l_next_offset, lmo->l_next_size); | |
197 | } | |
198 | ||
199 | static CORE_ADDR | |
200 | LM_NAME (struct so_list *so) | |
201 | { | |
202 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
203 | ||
204 | return extract_address (so->lm_info->lm + lmo->l_name_offset, lmo->l_name_size); | |
205 | } | |
206 | ||
207 | #ifndef SVR4_SHARED_LIBS | |
208 | ||
209 | static int | |
210 | IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list *so) | |
211 | { | |
212 | return 0; | |
213 | } | |
214 | ||
215 | #else /* SVR4_SHARED_LIBS */ | |
216 | ||
217 | static int | |
218 | IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list *so) | |
219 | { | |
220 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
221 | ||
222 | return extract_address (so->lm_info->lm + lmo->l_prev_offset, | |
223 | lmo->l_prev_size) == 0; | |
224 | } | |
225 | ||
226 | #endif /* !SVR4_SHARED_LIBS */ | |
227 | ||
13437d4b KB |
228 | static CORE_ADDR debug_base; /* Base of dynamic linker structures */ |
229 | static CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */ | |
230 | ||
231 | /* Local function prototypes */ | |
232 | ||
233 | static int match_main (char *); | |
234 | ||
13437d4b KB |
235 | #ifndef SVR4_SHARED_LIBS |
236 | ||
237 | /* Allocate the runtime common object file. */ | |
238 | ||
239 | static void | |
240 | allocate_rt_common_objfile (void) | |
241 | { | |
242 | struct objfile *objfile; | |
243 | struct objfile *last_one; | |
244 | ||
245 | objfile = (struct objfile *) xmalloc (sizeof (struct objfile)); | |
246 | memset (objfile, 0, sizeof (struct objfile)); | |
247 | objfile->md = NULL; | |
248 | obstack_specify_allocation (&objfile->psymbol_cache.cache, 0, 0, | |
b8c9b27d | 249 | xmalloc, xfree); |
13437d4b | 250 | obstack_specify_allocation (&objfile->psymbol_obstack, 0, 0, xmalloc, |
b8c9b27d | 251 | xfree); |
13437d4b | 252 | obstack_specify_allocation (&objfile->symbol_obstack, 0, 0, xmalloc, |
b8c9b27d | 253 | xfree); |
13437d4b | 254 | obstack_specify_allocation (&objfile->type_obstack, 0, 0, xmalloc, |
b8c9b27d | 255 | xfree); |
13437d4b KB |
256 | objfile->name = mstrsave (objfile->md, "rt_common"); |
257 | ||
258 | /* Add this file onto the tail of the linked list of other such files. */ | |
259 | ||
260 | objfile->next = NULL; | |
261 | if (object_files == NULL) | |
262 | object_files = objfile; | |
263 | else | |
264 | { | |
265 | for (last_one = object_files; | |
266 | last_one->next; | |
267 | last_one = last_one->next); | |
268 | last_one->next = objfile; | |
269 | } | |
270 | ||
271 | rt_common_objfile = objfile; | |
272 | } | |
273 | ||
274 | /* Read all dynamically loaded common symbol definitions from the inferior | |
275 | and put them into the minimal symbol table for the runtime common | |
276 | objfile. */ | |
277 | ||
278 | static void | |
279 | solib_add_common_symbols (CORE_ADDR rtc_symp) | |
280 | { | |
281 | struct rtc_symb inferior_rtc_symb; | |
282 | struct nlist inferior_rtc_nlist; | |
283 | int len; | |
284 | char *name; | |
285 | ||
286 | /* Remove any runtime common symbols from previous runs. */ | |
287 | ||
288 | if (rt_common_objfile != NULL && rt_common_objfile->minimal_symbol_count) | |
289 | { | |
290 | obstack_free (&rt_common_objfile->symbol_obstack, 0); | |
291 | obstack_specify_allocation (&rt_common_objfile->symbol_obstack, 0, 0, | |
b8c9b27d | 292 | xmalloc, xfree); |
13437d4b KB |
293 | rt_common_objfile->minimal_symbol_count = 0; |
294 | rt_common_objfile->msymbols = NULL; | |
295 | } | |
296 | ||
297 | init_minimal_symbol_collection (); | |
298 | make_cleanup_discard_minimal_symbols (); | |
299 | ||
300 | while (rtc_symp) | |
301 | { | |
302 | read_memory (rtc_symp, | |
303 | (char *) &inferior_rtc_symb, | |
304 | sizeof (inferior_rtc_symb)); | |
305 | read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_sp), | |
306 | (char *) &inferior_rtc_nlist, | |
307 | sizeof (inferior_rtc_nlist)); | |
308 | if (inferior_rtc_nlist.n_type == N_COMM) | |
309 | { | |
310 | /* FIXME: The length of the symbol name is not available, but in the | |
311 | current implementation the common symbol is allocated immediately | |
312 | behind the name of the symbol. */ | |
313 | len = inferior_rtc_nlist.n_value - inferior_rtc_nlist.n_un.n_strx; | |
314 | ||
315 | name = xmalloc (len); | |
316 | read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_nlist.n_un.n_name), | |
317 | name, len); | |
318 | ||
319 | /* Allocate the runtime common objfile if necessary. */ | |
320 | if (rt_common_objfile == NULL) | |
321 | allocate_rt_common_objfile (); | |
322 | ||
323 | prim_record_minimal_symbol (name, inferior_rtc_nlist.n_value, | |
324 | mst_bss, rt_common_objfile); | |
b8c9b27d | 325 | xfree (name); |
13437d4b KB |
326 | } |
327 | rtc_symp = SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_next); | |
328 | } | |
329 | ||
330 | /* Install any minimal symbols that have been collected as the current | |
331 | minimal symbols for the runtime common objfile. */ | |
332 | ||
333 | install_minimal_symbols (rt_common_objfile); | |
334 | } | |
335 | ||
336 | #endif /* SVR4_SHARED_LIBS */ | |
337 | ||
338 | ||
339 | #ifdef SVR4_SHARED_LIBS | |
340 | ||
341 | static CORE_ADDR bfd_lookup_symbol (bfd *, char *); | |
342 | ||
343 | /* | |
344 | ||
345 | LOCAL FUNCTION | |
346 | ||
347 | bfd_lookup_symbol -- lookup the value for a specific symbol | |
348 | ||
349 | SYNOPSIS | |
350 | ||
351 | CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname) | |
352 | ||
353 | DESCRIPTION | |
354 | ||
355 | An expensive way to lookup the value of a single symbol for | |
356 | bfd's that are only temporary anyway. This is used by the | |
357 | shared library support to find the address of the debugger | |
358 | interface structures in the shared library. | |
359 | ||
360 | Note that 0 is specifically allowed as an error return (no | |
361 | such symbol). | |
362 | */ | |
363 | ||
364 | static CORE_ADDR | |
365 | bfd_lookup_symbol (bfd *abfd, char *symname) | |
366 | { | |
435b259c | 367 | long storage_needed; |
13437d4b KB |
368 | asymbol *sym; |
369 | asymbol **symbol_table; | |
370 | unsigned int number_of_symbols; | |
371 | unsigned int i; | |
372 | struct cleanup *back_to; | |
373 | CORE_ADDR symaddr = 0; | |
374 | ||
375 | storage_needed = bfd_get_symtab_upper_bound (abfd); | |
376 | ||
377 | if (storage_needed > 0) | |
378 | { | |
379 | symbol_table = (asymbol **) xmalloc (storage_needed); | |
b8c9b27d | 380 | back_to = make_cleanup (xfree, (PTR) symbol_table); |
13437d4b KB |
381 | number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); |
382 | ||
383 | for (i = 0; i < number_of_symbols; i++) | |
384 | { | |
385 | sym = *symbol_table++; | |
386 | if (STREQ (sym->name, symname)) | |
387 | { | |
388 | /* Bfd symbols are section relative. */ | |
389 | symaddr = sym->value + sym->section->vma; | |
390 | break; | |
391 | } | |
392 | } | |
393 | do_cleanups (back_to); | |
394 | } | |
395 | ||
396 | if (symaddr) | |
397 | return symaddr; | |
398 | ||
399 | /* On FreeBSD, the dynamic linker is stripped by default. So we'll | |
400 | have to check the dynamic string table too. */ | |
401 | ||
402 | storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd); | |
403 | ||
404 | if (storage_needed > 0) | |
405 | { | |
406 | symbol_table = (asymbol **) xmalloc (storage_needed); | |
b8c9b27d | 407 | back_to = make_cleanup (xfree, (PTR) symbol_table); |
13437d4b KB |
408 | number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table); |
409 | ||
410 | for (i = 0; i < number_of_symbols; i++) | |
411 | { | |
412 | sym = *symbol_table++; | |
413 | if (STREQ (sym->name, symname)) | |
414 | { | |
415 | /* Bfd symbols are section relative. */ | |
416 | symaddr = sym->value + sym->section->vma; | |
417 | break; | |
418 | } | |
419 | } | |
420 | do_cleanups (back_to); | |
421 | } | |
422 | ||
423 | return symaddr; | |
424 | } | |
425 | ||
426 | #ifdef HANDLE_SVR4_EXEC_EMULATORS | |
427 | ||
428 | /* | |
429 | Solaris BCP (the part of Solaris which allows it to run SunOS4 | |
430 | a.out files) throws in another wrinkle. Solaris does not fill | |
431 | in the usual a.out link map structures when running BCP programs, | |
432 | the only way to get at them is via groping around in the dynamic | |
433 | linker. | |
434 | The dynamic linker and it's structures are located in the shared | |
435 | C library, which gets run as the executable's "interpreter" by | |
436 | the kernel. | |
437 | ||
438 | Note that we can assume nothing about the process state at the time | |
439 | we need to find these structures. We may be stopped on the first | |
440 | instruction of the interpreter (C shared library), the first | |
441 | instruction of the executable itself, or somewhere else entirely | |
442 | (if we attached to the process for example). | |
443 | */ | |
444 | ||
445 | static char *debug_base_symbols[] = | |
446 | { | |
447 | "r_debug", /* Solaris 2.3 */ | |
448 | "_r_debug", /* Solaris 2.1, 2.2 */ | |
449 | NULL | |
450 | }; | |
451 | ||
452 | static int look_for_base (int, CORE_ADDR); | |
453 | ||
454 | /* | |
455 | ||
456 | LOCAL FUNCTION | |
457 | ||
458 | look_for_base -- examine file for each mapped address segment | |
459 | ||
460 | SYNOPSYS | |
461 | ||
462 | static int look_for_base (int fd, CORE_ADDR baseaddr) | |
463 | ||
464 | DESCRIPTION | |
465 | ||
466 | This function is passed to proc_iterate_over_mappings, which | |
467 | causes it to get called once for each mapped address space, with | |
468 | an open file descriptor for the file mapped to that space, and the | |
469 | base address of that mapped space. | |
470 | ||
471 | Our job is to find the debug base symbol in the file that this | |
472 | fd is open on, if it exists, and if so, initialize the dynamic | |
473 | linker structure base address debug_base. | |
474 | ||
475 | Note that this is a computationally expensive proposition, since | |
476 | we basically have to open a bfd on every call, so we specifically | |
477 | avoid opening the exec file. | |
478 | */ | |
479 | ||
480 | static int | |
481 | look_for_base (int fd, CORE_ADDR baseaddr) | |
482 | { | |
483 | bfd *interp_bfd; | |
484 | CORE_ADDR address = 0; | |
485 | char **symbolp; | |
486 | ||
487 | /* If the fd is -1, then there is no file that corresponds to this | |
488 | mapped memory segment, so skip it. Also, if the fd corresponds | |
489 | to the exec file, skip it as well. */ | |
490 | ||
491 | if (fd == -1 | |
492 | || (exec_bfd != NULL | |
493 | && fdmatch (fileno ((FILE *) (exec_bfd->iostream)), fd))) | |
494 | { | |
495 | return (0); | |
496 | } | |
497 | ||
498 | /* Try to open whatever random file this fd corresponds to. Note that | |
499 | we have no way currently to find the filename. Don't gripe about | |
500 | any problems we might have, just fail. */ | |
501 | ||
502 | if ((interp_bfd = bfd_fdopenr ("unnamed", gnutarget, fd)) == NULL) | |
503 | { | |
504 | return (0); | |
505 | } | |
506 | if (!bfd_check_format (interp_bfd, bfd_object)) | |
507 | { | |
508 | /* FIXME-leak: on failure, might not free all memory associated with | |
509 | interp_bfd. */ | |
510 | bfd_close (interp_bfd); | |
511 | return (0); | |
512 | } | |
513 | ||
514 | /* Now try to find our debug base symbol in this file, which we at | |
515 | least know to be a valid ELF executable or shared library. */ | |
516 | ||
517 | for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++) | |
518 | { | |
519 | address = bfd_lookup_symbol (interp_bfd, *symbolp); | |
520 | if (address != 0) | |
521 | { | |
522 | break; | |
523 | } | |
524 | } | |
525 | if (address == 0) | |
526 | { | |
527 | /* FIXME-leak: on failure, might not free all memory associated with | |
528 | interp_bfd. */ | |
529 | bfd_close (interp_bfd); | |
530 | return (0); | |
531 | } | |
532 | ||
533 | /* Eureka! We found the symbol. But now we may need to relocate it | |
534 | by the base address. If the symbol's value is less than the base | |
535 | address of the shared library, then it hasn't yet been relocated | |
536 | by the dynamic linker, and we have to do it ourself. FIXME: Note | |
537 | that we make the assumption that the first segment that corresponds | |
538 | to the shared library has the base address to which the library | |
539 | was relocated. */ | |
540 | ||
541 | if (address < baseaddr) | |
542 | { | |
543 | address += baseaddr; | |
544 | } | |
545 | debug_base = address; | |
546 | /* FIXME-leak: on failure, might not free all memory associated with | |
547 | interp_bfd. */ | |
548 | bfd_close (interp_bfd); | |
549 | return (1); | |
550 | } | |
551 | #endif /* HANDLE_SVR4_EXEC_EMULATORS */ | |
552 | ||
553 | /* | |
554 | ||
555 | LOCAL FUNCTION | |
556 | ||
557 | elf_locate_base -- locate the base address of dynamic linker structs | |
558 | for SVR4 elf targets. | |
559 | ||
560 | SYNOPSIS | |
561 | ||
562 | CORE_ADDR elf_locate_base (void) | |
563 | ||
564 | DESCRIPTION | |
565 | ||
566 | For SVR4 elf targets the address of the dynamic linker's runtime | |
567 | structure is contained within the dynamic info section in the | |
568 | executable file. The dynamic section is also mapped into the | |
569 | inferior address space. Because the runtime loader fills in the | |
570 | real address before starting the inferior, we have to read in the | |
571 | dynamic info section from the inferior address space. | |
572 | If there are any errors while trying to find the address, we | |
573 | silently return 0, otherwise the found address is returned. | |
574 | ||
575 | */ | |
576 | ||
577 | static CORE_ADDR | |
578 | elf_locate_base (void) | |
579 | { | |
580 | sec_ptr dyninfo_sect; | |
581 | int dyninfo_sect_size; | |
582 | CORE_ADDR dyninfo_addr; | |
583 | char *buf; | |
584 | char *bufend; | |
585 | int arch_size; | |
586 | ||
587 | /* Find the start address of the .dynamic section. */ | |
588 | dyninfo_sect = bfd_get_section_by_name (exec_bfd, ".dynamic"); | |
589 | if (dyninfo_sect == NULL) | |
590 | return 0; | |
591 | dyninfo_addr = bfd_section_vma (exec_bfd, dyninfo_sect); | |
592 | ||
593 | /* Read in .dynamic section, silently ignore errors. */ | |
594 | dyninfo_sect_size = bfd_section_size (exec_bfd, dyninfo_sect); | |
595 | buf = alloca (dyninfo_sect_size); | |
596 | if (target_read_memory (dyninfo_addr, buf, dyninfo_sect_size)) | |
597 | return 0; | |
598 | ||
599 | /* Find the DT_DEBUG entry in the the .dynamic section. | |
600 | For mips elf we look for DT_MIPS_RLD_MAP, mips elf apparently has | |
601 | no DT_DEBUG entries. */ | |
602 | ||
603 | arch_size = bfd_get_arch_size (exec_bfd); | |
604 | if (arch_size == -1) /* failure */ | |
605 | return 0; | |
606 | ||
607 | if (arch_size == 32) | |
608 | { /* 32-bit elf */ | |
609 | for (bufend = buf + dyninfo_sect_size; | |
610 | buf < bufend; | |
611 | buf += sizeof (Elf32_External_Dyn)) | |
612 | { | |
613 | Elf32_External_Dyn *x_dynp = (Elf32_External_Dyn *) buf; | |
614 | long dyn_tag; | |
615 | CORE_ADDR dyn_ptr; | |
616 | ||
617 | dyn_tag = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_tag); | |
618 | if (dyn_tag == DT_NULL) | |
619 | break; | |
620 | else if (dyn_tag == DT_DEBUG) | |
621 | { | |
622 | dyn_ptr = bfd_h_get_32 (exec_bfd, | |
623 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
624 | return dyn_ptr; | |
625 | } | |
626 | #ifdef DT_MIPS_RLD_MAP | |
627 | else if (dyn_tag == DT_MIPS_RLD_MAP) | |
628 | { | |
629 | char *pbuf; | |
630 | ||
631 | pbuf = alloca (TARGET_PTR_BIT / HOST_CHAR_BIT); | |
632 | /* DT_MIPS_RLD_MAP contains a pointer to the address | |
633 | of the dynamic link structure. */ | |
634 | dyn_ptr = bfd_h_get_32 (exec_bfd, | |
635 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
636 | if (target_read_memory (dyn_ptr, pbuf, sizeof (pbuf))) | |
637 | return 0; | |
638 | return extract_unsigned_integer (pbuf, sizeof (pbuf)); | |
639 | } | |
640 | #endif | |
641 | } | |
642 | } | |
643 | else /* 64-bit elf */ | |
644 | { | |
645 | for (bufend = buf + dyninfo_sect_size; | |
646 | buf < bufend; | |
647 | buf += sizeof (Elf64_External_Dyn)) | |
648 | { | |
649 | Elf64_External_Dyn *x_dynp = (Elf64_External_Dyn *) buf; | |
650 | long dyn_tag; | |
651 | CORE_ADDR dyn_ptr; | |
652 | ||
653 | dyn_tag = bfd_h_get_64 (exec_bfd, (bfd_byte *) x_dynp->d_tag); | |
654 | if (dyn_tag == DT_NULL) | |
655 | break; | |
656 | else if (dyn_tag == DT_DEBUG) | |
657 | { | |
658 | dyn_ptr = bfd_h_get_64 (exec_bfd, | |
659 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
660 | return dyn_ptr; | |
661 | } | |
662 | } | |
663 | } | |
664 | ||
665 | /* DT_DEBUG entry not found. */ | |
666 | return 0; | |
667 | } | |
668 | ||
669 | #endif /* SVR4_SHARED_LIBS */ | |
670 | ||
671 | /* | |
672 | ||
673 | LOCAL FUNCTION | |
674 | ||
675 | locate_base -- locate the base address of dynamic linker structs | |
676 | ||
677 | SYNOPSIS | |
678 | ||
679 | CORE_ADDR locate_base (void) | |
680 | ||
681 | DESCRIPTION | |
682 | ||
683 | For both the SunOS and SVR4 shared library implementations, if the | |
684 | inferior executable has been linked dynamically, there is a single | |
685 | address somewhere in the inferior's data space which is the key to | |
686 | locating all of the dynamic linker's runtime structures. This | |
687 | address is the value of the debug base symbol. The job of this | |
688 | function is to find and return that address, or to return 0 if there | |
689 | is no such address (the executable is statically linked for example). | |
690 | ||
691 | For SunOS, the job is almost trivial, since the dynamic linker and | |
692 | all of it's structures are statically linked to the executable at | |
693 | link time. Thus the symbol for the address we are looking for has | |
694 | already been added to the minimal symbol table for the executable's | |
695 | objfile at the time the symbol file's symbols were read, and all we | |
696 | have to do is look it up there. Note that we explicitly do NOT want | |
697 | to find the copies in the shared library. | |
698 | ||
699 | The SVR4 version is a bit more complicated because the address | |
700 | is contained somewhere in the dynamic info section. We have to go | |
701 | to a lot more work to discover the address of the debug base symbol. | |
702 | Because of this complexity, we cache the value we find and return that | |
703 | value on subsequent invocations. Note there is no copy in the | |
704 | executable symbol tables. | |
705 | ||
706 | */ | |
707 | ||
708 | static CORE_ADDR | |
709 | locate_base (void) | |
710 | { | |
711 | ||
712 | #ifndef SVR4_SHARED_LIBS | |
713 | ||
714 | struct minimal_symbol *msymbol; | |
715 | CORE_ADDR address = 0; | |
716 | char **symbolp; | |
717 | ||
718 | /* For SunOS, we want to limit the search for the debug base symbol to the | |
719 | executable being debugged, since there is a duplicate named symbol in the | |
720 | shared library. We don't want the shared library versions. */ | |
721 | ||
722 | for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++) | |
723 | { | |
724 | msymbol = lookup_minimal_symbol (*symbolp, NULL, symfile_objfile); | |
725 | if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) | |
726 | { | |
727 | address = SYMBOL_VALUE_ADDRESS (msymbol); | |
728 | return (address); | |
729 | } | |
730 | } | |
731 | return (0); | |
732 | ||
733 | #else /* SVR4_SHARED_LIBS */ | |
734 | ||
735 | /* Check to see if we have a currently valid address, and if so, avoid | |
736 | doing all this work again and just return the cached address. If | |
737 | we have no cached address, try to locate it in the dynamic info | |
738 | section for ELF executables. */ | |
739 | ||
740 | if (debug_base == 0) | |
741 | { | |
742 | if (exec_bfd != NULL | |
743 | && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) | |
744 | debug_base = elf_locate_base (); | |
745 | #ifdef HANDLE_SVR4_EXEC_EMULATORS | |
746 | /* Try it the hard way for emulated executables. */ | |
39f77062 | 747 | else if (!ptid_equal (inferior_ptid, null_ptid) && target_has_execution) |
13437d4b KB |
748 | proc_iterate_over_mappings (look_for_base); |
749 | #endif | |
750 | } | |
751 | return (debug_base); | |
752 | ||
753 | #endif /* !SVR4_SHARED_LIBS */ | |
754 | ||
755 | } | |
756 | ||
757 | /* | |
758 | ||
759 | LOCAL FUNCTION | |
760 | ||
761 | first_link_map_member -- locate first member in dynamic linker's map | |
762 | ||
763 | SYNOPSIS | |
764 | ||
765 | static CORE_ADDR first_link_map_member (void) | |
766 | ||
767 | DESCRIPTION | |
768 | ||
769 | Find the first element in the inferior's dynamic link map, and | |
770 | return its address in the inferior. This function doesn't copy the | |
771 | link map entry itself into our address space; current_sos actually | |
772 | does the reading. */ | |
773 | ||
774 | static CORE_ADDR | |
775 | first_link_map_member (void) | |
776 | { | |
777 | CORE_ADDR lm = 0; | |
778 | ||
779 | #ifndef SVR4_SHARED_LIBS | |
780 | ||
781 | read_memory (debug_base, (char *) &dynamic_copy, sizeof (dynamic_copy)); | |
782 | if (dynamic_copy.ld_version >= 2) | |
783 | { | |
784 | /* It is a version that we can deal with, so read in the secondary | |
785 | structure and find the address of the link map list from it. */ | |
786 | read_memory (SOLIB_EXTRACT_ADDRESS (dynamic_copy.ld_un.ld_2), | |
787 | (char *) &ld_2_copy, sizeof (struct link_dynamic_2)); | |
788 | lm = SOLIB_EXTRACT_ADDRESS (ld_2_copy.ld_loaded); | |
789 | } | |
790 | ||
791 | #else /* SVR4_SHARED_LIBS */ | |
792 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
793 | char *r_map_buf = xmalloc (lmo->r_map_size); | |
b8c9b27d | 794 | struct cleanup *cleanups = make_cleanup (xfree, r_map_buf); |
13437d4b KB |
795 | |
796 | read_memory (debug_base + lmo->r_map_offset, r_map_buf, lmo->r_map_size); | |
797 | ||
798 | lm = extract_address (r_map_buf, lmo->r_map_size); | |
799 | ||
800 | /* FIXME: Perhaps we should validate the info somehow, perhaps by | |
801 | checking r_version for a known version number, or r_state for | |
802 | RT_CONSISTENT. */ | |
803 | ||
804 | do_cleanups (cleanups); | |
805 | ||
806 | #endif /* !SVR4_SHARED_LIBS */ | |
807 | ||
808 | return (lm); | |
809 | } | |
810 | ||
811 | #ifdef SVR4_SHARED_LIBS | |
812 | /* | |
813 | ||
814 | LOCAL FUNCTION | |
815 | ||
816 | open_symbol_file_object | |
817 | ||
818 | SYNOPSIS | |
819 | ||
820 | void open_symbol_file_object (void *from_tty) | |
821 | ||
822 | DESCRIPTION | |
823 | ||
824 | If no open symbol file, attempt to locate and open the main symbol | |
825 | file. On SVR4 systems, this is the first link map entry. If its | |
826 | name is here, we can open it. Useful when attaching to a process | |
827 | without first loading its symbol file. | |
828 | ||
829 | If FROM_TTYP dereferences to a non-zero integer, allow messages to | |
830 | be printed. This parameter is a pointer rather than an int because | |
831 | open_symbol_file_object() is called via catch_errors() and | |
832 | catch_errors() requires a pointer argument. */ | |
833 | ||
834 | static int | |
835 | open_symbol_file_object (void *from_ttyp) | |
836 | { | |
837 | CORE_ADDR lm, l_name; | |
838 | char *filename; | |
839 | int errcode; | |
840 | int from_tty = *(int *)from_ttyp; | |
841 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
842 | char *l_name_buf = xmalloc (lmo->l_name_size); | |
b8c9b27d | 843 | struct cleanup *cleanups = make_cleanup (xfree, l_name_buf); |
13437d4b KB |
844 | |
845 | if (symfile_objfile) | |
846 | if (!query ("Attempt to reload symbols from process? ")) | |
847 | return 0; | |
848 | ||
849 | if ((debug_base = locate_base ()) == 0) | |
850 | return 0; /* failed somehow... */ | |
851 | ||
852 | /* First link map member should be the executable. */ | |
853 | if ((lm = first_link_map_member ()) == 0) | |
854 | return 0; /* failed somehow... */ | |
855 | ||
856 | /* Read address of name from target memory to GDB. */ | |
857 | read_memory (lm + lmo->l_name_offset, l_name_buf, lmo->l_name_size); | |
858 | ||
859 | /* Convert the address to host format. */ | |
860 | l_name = extract_address (l_name_buf, lmo->l_name_size); | |
861 | ||
862 | /* Free l_name_buf. */ | |
863 | do_cleanups (cleanups); | |
864 | ||
865 | if (l_name == 0) | |
866 | return 0; /* No filename. */ | |
867 | ||
868 | /* Now fetch the filename from target memory. */ | |
869 | target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode); | |
870 | ||
871 | if (errcode) | |
872 | { | |
873 | warning ("failed to read exec filename from attached file: %s", | |
874 | safe_strerror (errcode)); | |
875 | return 0; | |
876 | } | |
877 | ||
b8c9b27d | 878 | make_cleanup (xfree, filename); |
13437d4b | 879 | /* Have a pathname: read the symbol file. */ |
1adeb98a | 880 | symbol_file_add_main (filename, from_tty); |
13437d4b KB |
881 | |
882 | return 1; | |
883 | } | |
884 | #else | |
885 | ||
886 | static int | |
21479ded | 887 | open_symbol_file_object (void *from_ttyp) |
13437d4b KB |
888 | { |
889 | return 1; | |
890 | } | |
891 | ||
892 | #endif /* SVR4_SHARED_LIBS */ | |
893 | ||
894 | ||
895 | /* LOCAL FUNCTION | |
896 | ||
897 | current_sos -- build a list of currently loaded shared objects | |
898 | ||
899 | SYNOPSIS | |
900 | ||
901 | struct so_list *current_sos () | |
902 | ||
903 | DESCRIPTION | |
904 | ||
905 | Build a list of `struct so_list' objects describing the shared | |
906 | objects currently loaded in the inferior. This list does not | |
907 | include an entry for the main executable file. | |
908 | ||
909 | Note that we only gather information directly available from the | |
910 | inferior --- we don't examine any of the shared library files | |
911 | themselves. The declaration of `struct so_list' says which fields | |
912 | we provide values for. */ | |
913 | ||
914 | static struct so_list * | |
915 | svr4_current_sos (void) | |
916 | { | |
917 | CORE_ADDR lm; | |
918 | struct so_list *head = 0; | |
919 | struct so_list **link_ptr = &head; | |
920 | ||
921 | /* Make sure we've looked up the inferior's dynamic linker's base | |
922 | structure. */ | |
923 | if (! debug_base) | |
924 | { | |
925 | debug_base = locate_base (); | |
926 | ||
927 | /* If we can't find the dynamic linker's base structure, this | |
928 | must not be a dynamically linked executable. Hmm. */ | |
929 | if (! debug_base) | |
930 | return 0; | |
931 | } | |
932 | ||
933 | /* Walk the inferior's link map list, and build our list of | |
934 | `struct so_list' nodes. */ | |
935 | lm = first_link_map_member (); | |
936 | while (lm) | |
937 | { | |
938 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
939 | struct so_list *new | |
940 | = (struct so_list *) xmalloc (sizeof (struct so_list)); | |
b8c9b27d | 941 | struct cleanup *old_chain = make_cleanup (xfree, new); |
13437d4b KB |
942 | |
943 | memset (new, 0, sizeof (*new)); | |
944 | ||
945 | new->lm_info = xmalloc (sizeof (struct lm_info)); | |
b8c9b27d | 946 | make_cleanup (xfree, new->lm_info); |
13437d4b KB |
947 | |
948 | new->lm_info->lm = xmalloc (lmo->link_map_size); | |
b8c9b27d | 949 | make_cleanup (xfree, new->lm_info->lm); |
13437d4b KB |
950 | memset (new->lm_info->lm, 0, lmo->link_map_size); |
951 | ||
952 | read_memory (lm, new->lm_info->lm, lmo->link_map_size); | |
953 | ||
954 | lm = LM_NEXT (new); | |
955 | ||
956 | /* For SVR4 versions, the first entry in the link map is for the | |
957 | inferior executable, so we must ignore it. For some versions of | |
958 | SVR4, it has no name. For others (Solaris 2.3 for example), it | |
959 | does have a name, so we can no longer use a missing name to | |
960 | decide when to ignore it. */ | |
961 | if (IGNORE_FIRST_LINK_MAP_ENTRY (new)) | |
962 | free_so (new); | |
963 | else | |
964 | { | |
965 | int errcode; | |
966 | char *buffer; | |
967 | ||
968 | /* Extract this shared object's name. */ | |
969 | target_read_string (LM_NAME (new), &buffer, | |
970 | SO_NAME_MAX_PATH_SIZE - 1, &errcode); | |
971 | if (errcode != 0) | |
972 | { | |
973 | warning ("current_sos: Can't read pathname for load map: %s\n", | |
974 | safe_strerror (errcode)); | |
975 | } | |
976 | else | |
977 | { | |
978 | strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1); | |
979 | new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; | |
b8c9b27d | 980 | xfree (buffer); |
13437d4b KB |
981 | strcpy (new->so_original_name, new->so_name); |
982 | } | |
983 | ||
984 | /* If this entry has no name, or its name matches the name | |
985 | for the main executable, don't include it in the list. */ | |
986 | if (! new->so_name[0] | |
987 | || match_main (new->so_name)) | |
988 | free_so (new); | |
989 | else | |
990 | { | |
991 | new->next = 0; | |
992 | *link_ptr = new; | |
993 | link_ptr = &new->next; | |
994 | } | |
995 | } | |
996 | ||
997 | discard_cleanups (old_chain); | |
998 | } | |
999 | ||
1000 | return head; | |
1001 | } | |
1002 | ||
1003 | ||
1004 | /* On some systems, the only way to recognize the link map entry for | |
1005 | the main executable file is by looking at its name. Return | |
1006 | non-zero iff SONAME matches one of the known main executable names. */ | |
1007 | ||
1008 | static int | |
1009 | match_main (char *soname) | |
1010 | { | |
1011 | char **mainp; | |
1012 | ||
1013 | for (mainp = main_name_list; *mainp != NULL; mainp++) | |
1014 | { | |
1015 | if (strcmp (soname, *mainp) == 0) | |
1016 | return (1); | |
1017 | } | |
1018 | ||
1019 | return (0); | |
1020 | } | |
1021 | ||
1022 | ||
13437d4b KB |
1023 | /* Return 1 if PC lies in the dynamic symbol resolution code of the |
1024 | SVR4 run time loader. */ | |
d7fa2ae2 | 1025 | #ifdef SVR4_SHARED_LIBS |
13437d4b KB |
1026 | static CORE_ADDR interp_text_sect_low; |
1027 | static CORE_ADDR interp_text_sect_high; | |
1028 | static CORE_ADDR interp_plt_sect_low; | |
1029 | static CORE_ADDR interp_plt_sect_high; | |
1030 | ||
d7fa2ae2 KB |
1031 | static int |
1032 | svr4_in_dynsym_resolve_code (CORE_ADDR pc) | |
13437d4b KB |
1033 | { |
1034 | return ((pc >= interp_text_sect_low && pc < interp_text_sect_high) | |
1035 | || (pc >= interp_plt_sect_low && pc < interp_plt_sect_high) | |
1036 | || in_plt_section (pc, NULL)); | |
1037 | } | |
d7fa2ae2 KB |
1038 | #else /* !SVR4_SHARED_LIBS */ |
1039 | static int | |
1040 | svr4_in_dynsym_resolve_code (CORE_ADDR pc) | |
1041 | { | |
1042 | return 0; | |
1043 | } | |
1044 | #endif /* SVR4_SHARED_LIBS */ | |
13437d4b KB |
1045 | |
1046 | /* | |
1047 | ||
1048 | LOCAL FUNCTION | |
1049 | ||
1050 | disable_break -- remove the "mapping changed" breakpoint | |
1051 | ||
1052 | SYNOPSIS | |
1053 | ||
1054 | static int disable_break () | |
1055 | ||
1056 | DESCRIPTION | |
1057 | ||
1058 | Removes the breakpoint that gets hit when the dynamic linker | |
1059 | completes a mapping change. | |
1060 | ||
1061 | */ | |
1062 | ||
1063 | #ifndef SVR4_SHARED_LIBS | |
1064 | ||
1065 | static int | |
1066 | disable_break (void) | |
1067 | { | |
1068 | int status = 1; | |
1069 | ||
1070 | int in_debugger = 0; | |
1071 | ||
1072 | /* Read the debugger structure from the inferior to retrieve the | |
1073 | address of the breakpoint and the original contents of the | |
1074 | breakpoint address. Remove the breakpoint by writing the original | |
1075 | contents back. */ | |
1076 | ||
1077 | read_memory (debug_addr, (char *) &debug_copy, sizeof (debug_copy)); | |
1078 | ||
1079 | /* Set `in_debugger' to zero now. */ | |
1080 | ||
1081 | write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger)); | |
1082 | ||
1083 | breakpoint_addr = SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_bp_addr); | |
1084 | write_memory (breakpoint_addr, (char *) &debug_copy.ldd_bp_inst, | |
1085 | sizeof (debug_copy.ldd_bp_inst)); | |
1086 | ||
1087 | /* For the SVR4 version, we always know the breakpoint address. For the | |
1088 | SunOS version we don't know it until the above code is executed. | |
1089 | Grumble if we are stopped anywhere besides the breakpoint address. */ | |
1090 | ||
1091 | if (stop_pc != breakpoint_addr) | |
1092 | { | |
1093 | warning ("stopped at unknown breakpoint while handling shared libraries"); | |
1094 | } | |
1095 | ||
1096 | return (status); | |
1097 | } | |
1098 | ||
1099 | #endif /* #ifdef SVR4_SHARED_LIBS */ | |
1100 | ||
1101 | /* | |
1102 | ||
1103 | LOCAL FUNCTION | |
1104 | ||
1105 | enable_break -- arrange for dynamic linker to hit breakpoint | |
1106 | ||
1107 | SYNOPSIS | |
1108 | ||
1109 | int enable_break (void) | |
1110 | ||
1111 | DESCRIPTION | |
1112 | ||
1113 | Both the SunOS and the SVR4 dynamic linkers have, as part of their | |
1114 | debugger interface, support for arranging for the inferior to hit | |
1115 | a breakpoint after mapping in the shared libraries. This function | |
1116 | enables that breakpoint. | |
1117 | ||
1118 | For SunOS, there is a special flag location (in_debugger) which we | |
1119 | set to 1. When the dynamic linker sees this flag set, it will set | |
1120 | a breakpoint at a location known only to itself, after saving the | |
1121 | original contents of that place and the breakpoint address itself, | |
1122 | in it's own internal structures. When we resume the inferior, it | |
1123 | will eventually take a SIGTRAP when it runs into the breakpoint. | |
1124 | We handle this (in a different place) by restoring the contents of | |
1125 | the breakpointed location (which is only known after it stops), | |
1126 | chasing around to locate the shared libraries that have been | |
1127 | loaded, then resuming. | |
1128 | ||
1129 | For SVR4, the debugger interface structure contains a member (r_brk) | |
1130 | which is statically initialized at the time the shared library is | |
1131 | built, to the offset of a function (_r_debug_state) which is guaran- | |
1132 | teed to be called once before mapping in a library, and again when | |
1133 | the mapping is complete. At the time we are examining this member, | |
1134 | it contains only the unrelocated offset of the function, so we have | |
1135 | to do our own relocation. Later, when the dynamic linker actually | |
1136 | runs, it relocates r_brk to be the actual address of _r_debug_state(). | |
1137 | ||
1138 | The debugger interface structure also contains an enumeration which | |
1139 | is set to either RT_ADD or RT_DELETE prior to changing the mapping, | |
1140 | depending upon whether or not the library is being mapped or unmapped, | |
1141 | and then set to RT_CONSISTENT after the library is mapped/unmapped. | |
1142 | */ | |
1143 | ||
1144 | static int | |
1145 | enable_break (void) | |
1146 | { | |
1147 | int success = 0; | |
1148 | ||
1149 | #ifndef SVR4_SHARED_LIBS | |
1150 | ||
1151 | int j; | |
1152 | int in_debugger; | |
1153 | ||
1154 | /* Get link_dynamic structure */ | |
1155 | ||
1156 | j = target_read_memory (debug_base, (char *) &dynamic_copy, | |
1157 | sizeof (dynamic_copy)); | |
1158 | if (j) | |
1159 | { | |
1160 | /* unreadable */ | |
1161 | return (0); | |
1162 | } | |
1163 | ||
1164 | /* Calc address of debugger interface structure */ | |
1165 | ||
1166 | debug_addr = SOLIB_EXTRACT_ADDRESS (dynamic_copy.ldd); | |
1167 | ||
1168 | /* Calc address of `in_debugger' member of debugger interface structure */ | |
1169 | ||
1170 | flag_addr = debug_addr + (CORE_ADDR) ((char *) &debug_copy.ldd_in_debugger - | |
1171 | (char *) &debug_copy); | |
1172 | ||
1173 | /* Write a value of 1 to this member. */ | |
1174 | ||
1175 | in_debugger = 1; | |
1176 | write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger)); | |
1177 | success = 1; | |
1178 | ||
1179 | #else /* SVR4_SHARED_LIBS */ | |
1180 | ||
1181 | #ifdef BKPT_AT_SYMBOL | |
1182 | ||
1183 | struct minimal_symbol *msymbol; | |
1184 | char **bkpt_namep; | |
1185 | asection *interp_sect; | |
1186 | ||
1187 | /* First, remove all the solib event breakpoints. Their addresses | |
1188 | may have changed since the last time we ran the program. */ | |
1189 | remove_solib_event_breakpoints (); | |
1190 | ||
1191 | #ifdef SVR4_SHARED_LIBS | |
1192 | interp_text_sect_low = interp_text_sect_high = 0; | |
1193 | interp_plt_sect_low = interp_plt_sect_high = 0; | |
1194 | ||
1195 | /* Find the .interp section; if not found, warn the user and drop | |
1196 | into the old breakpoint at symbol code. */ | |
1197 | interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); | |
1198 | if (interp_sect) | |
1199 | { | |
1200 | unsigned int interp_sect_size; | |
1201 | char *buf; | |
1202 | CORE_ADDR load_addr; | |
e4f7b8c8 MS |
1203 | bfd *tmp_bfd = NULL; |
1204 | int tmp_fd = -1; | |
1205 | char *tmp_pathname = NULL; | |
13437d4b KB |
1206 | CORE_ADDR sym_addr = 0; |
1207 | ||
1208 | /* Read the contents of the .interp section into a local buffer; | |
1209 | the contents specify the dynamic linker this program uses. */ | |
1210 | interp_sect_size = bfd_section_size (exec_bfd, interp_sect); | |
1211 | buf = alloca (interp_sect_size); | |
1212 | bfd_get_section_contents (exec_bfd, interp_sect, | |
1213 | buf, 0, interp_sect_size); | |
1214 | ||
1215 | /* Now we need to figure out where the dynamic linker was | |
1216 | loaded so that we can load its symbols and place a breakpoint | |
1217 | in the dynamic linker itself. | |
1218 | ||
1219 | This address is stored on the stack. However, I've been unable | |
1220 | to find any magic formula to find it for Solaris (appears to | |
1221 | be trivial on GNU/Linux). Therefore, we have to try an alternate | |
1222 | mechanism to find the dynamic linker's base address. */ | |
e4f7b8c8 MS |
1223 | |
1224 | tmp_fd = solib_open (buf, &tmp_pathname); | |
1225 | if (tmp_fd >= 0) | |
1226 | tmp_bfd = bfd_fdopenr (tmp_pathname, gnutarget, tmp_fd); | |
1227 | ||
13437d4b KB |
1228 | if (tmp_bfd == NULL) |
1229 | goto bkpt_at_symbol; | |
1230 | ||
1231 | /* Make sure the dynamic linker's really a useful object. */ | |
1232 | if (!bfd_check_format (tmp_bfd, bfd_object)) | |
1233 | { | |
1234 | warning ("Unable to grok dynamic linker %s as an object file", buf); | |
1235 | bfd_close (tmp_bfd); | |
1236 | goto bkpt_at_symbol; | |
1237 | } | |
1238 | ||
1239 | /* We find the dynamic linker's base address by examining the | |
1240 | current pc (which point at the entry point for the dynamic | |
1241 | linker) and subtracting the offset of the entry point. */ | |
1242 | load_addr = read_pc () - tmp_bfd->start_address; | |
1243 | ||
1244 | /* Record the relocated start and end address of the dynamic linker | |
d7fa2ae2 | 1245 | text and plt section for svr4_in_dynsym_resolve_code. */ |
13437d4b KB |
1246 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
1247 | if (interp_sect) | |
1248 | { | |
1249 | interp_text_sect_low = | |
1250 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
1251 | interp_text_sect_high = | |
1252 | interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
1253 | } | |
1254 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); | |
1255 | if (interp_sect) | |
1256 | { | |
1257 | interp_plt_sect_low = | |
1258 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
1259 | interp_plt_sect_high = | |
1260 | interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
1261 | } | |
1262 | ||
1263 | /* Now try to set a breakpoint in the dynamic linker. */ | |
1264 | for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) | |
1265 | { | |
1266 | sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep); | |
1267 | if (sym_addr != 0) | |
1268 | break; | |
1269 | } | |
1270 | ||
1271 | /* We're done with the temporary bfd. */ | |
1272 | bfd_close (tmp_bfd); | |
1273 | ||
1274 | if (sym_addr != 0) | |
1275 | { | |
1276 | create_solib_event_breakpoint (load_addr + sym_addr); | |
1277 | return 1; | |
1278 | } | |
1279 | ||
1280 | /* For whatever reason we couldn't set a breakpoint in the dynamic | |
1281 | linker. Warn and drop into the old code. */ | |
1282 | bkpt_at_symbol: | |
1283 | warning ("Unable to find dynamic linker breakpoint function.\nGDB will be unable to debug shared library initializers\nand track explicitly loaded dynamic code."); | |
1284 | } | |
1285 | #endif | |
1286 | ||
1287 | /* Scan through the list of symbols, trying to look up the symbol and | |
1288 | set a breakpoint there. Terminate loop when we/if we succeed. */ | |
1289 | ||
1290 | breakpoint_addr = 0; | |
1291 | for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++) | |
1292 | { | |
1293 | msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); | |
1294 | if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) | |
1295 | { | |
1296 | create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol)); | |
1297 | return 1; | |
1298 | } | |
1299 | } | |
1300 | ||
1301 | /* Nothing good happened. */ | |
1302 | success = 0; | |
1303 | ||
1304 | #endif /* BKPT_AT_SYMBOL */ | |
1305 | ||
1306 | #endif /* !SVR4_SHARED_LIBS */ | |
1307 | ||
1308 | return (success); | |
1309 | } | |
1310 | ||
1311 | /* | |
1312 | ||
1313 | LOCAL FUNCTION | |
1314 | ||
1315 | special_symbol_handling -- additional shared library symbol handling | |
1316 | ||
1317 | SYNOPSIS | |
1318 | ||
1319 | void special_symbol_handling () | |
1320 | ||
1321 | DESCRIPTION | |
1322 | ||
1323 | Once the symbols from a shared object have been loaded in the usual | |
1324 | way, we are called to do any system specific symbol handling that | |
1325 | is needed. | |
1326 | ||
1327 | For SunOS4, this consists of grunging around in the dynamic | |
1328 | linkers structures to find symbol definitions for "common" symbols | |
1329 | and adding them to the minimal symbol table for the runtime common | |
1330 | objfile. | |
1331 | ||
1332 | */ | |
1333 | ||
1334 | static void | |
1335 | svr4_special_symbol_handling (void) | |
1336 | { | |
1337 | #ifndef SVR4_SHARED_LIBS | |
1338 | int j; | |
1339 | ||
1340 | if (debug_addr == 0) | |
1341 | { | |
1342 | /* Get link_dynamic structure */ | |
1343 | ||
1344 | j = target_read_memory (debug_base, (char *) &dynamic_copy, | |
1345 | sizeof (dynamic_copy)); | |
1346 | if (j) | |
1347 | { | |
1348 | /* unreadable */ | |
1349 | return; | |
1350 | } | |
1351 | ||
1352 | /* Calc address of debugger interface structure */ | |
1353 | /* FIXME, this needs work for cross-debugging of core files | |
1354 | (byteorder, size, alignment, etc). */ | |
1355 | ||
1356 | debug_addr = SOLIB_EXTRACT_ADDRESS (dynamic_copy.ldd); | |
1357 | } | |
1358 | ||
1359 | /* Read the debugger structure from the inferior, just to make sure | |
1360 | we have a current copy. */ | |
1361 | ||
1362 | j = target_read_memory (debug_addr, (char *) &debug_copy, | |
1363 | sizeof (debug_copy)); | |
1364 | if (j) | |
1365 | return; /* unreadable */ | |
1366 | ||
1367 | /* Get common symbol definitions for the loaded object. */ | |
1368 | ||
1369 | if (debug_copy.ldd_cp) | |
1370 | { | |
1371 | solib_add_common_symbols (SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_cp)); | |
1372 | } | |
1373 | ||
1374 | #endif /* !SVR4_SHARED_LIBS */ | |
1375 | } | |
1376 | ||
e2a44558 KB |
1377 | /* Relocate the main executable. This function should be called upon |
1378 | stopping the inferior process at the entry point to the program. | |
1379 | The entry point from BFD is compared to the PC and if they are | |
1380 | different, the main executable is relocated by the proper amount. | |
1381 | ||
1382 | As written it will only attempt to relocate executables which | |
1383 | lack interpreter sections. It seems likely that only dynamic | |
1384 | linker executables will get relocated, though it should work | |
1385 | properly for a position-independent static executable as well. */ | |
1386 | ||
1387 | static void | |
1388 | svr4_relocate_main_executable (void) | |
1389 | { | |
1390 | asection *interp_sect; | |
1391 | CORE_ADDR pc = read_pc (); | |
1392 | ||
1393 | /* Decide if the objfile needs to be relocated. As indicated above, | |
1394 | we will only be here when execution is stopped at the beginning | |
1395 | of the program. Relocation is necessary if the address at which | |
1396 | we are presently stopped differs from the start address stored in | |
1397 | the executable AND there's no interpreter section. The condition | |
1398 | regarding the interpreter section is very important because if | |
1399 | there *is* an interpreter section, execution will begin there | |
1400 | instead. When there is an interpreter section, the start address | |
1401 | is (presumably) used by the interpreter at some point to start | |
1402 | execution of the program. | |
1403 | ||
1404 | If there is an interpreter, it is normal for it to be set to an | |
1405 | arbitrary address at the outset. The job of finding it is | |
1406 | handled in enable_break(). | |
1407 | ||
1408 | So, to summarize, relocations are necessary when there is no | |
1409 | interpreter section and the start address obtained from the | |
1410 | executable is different from the address at which GDB is | |
1411 | currently stopped. | |
1412 | ||
1413 | [ The astute reader will note that we also test to make sure that | |
1414 | the executable in question has the DYNAMIC flag set. It is my | |
1415 | opinion that this test is unnecessary (undesirable even). It | |
1416 | was added to avoid inadvertent relocation of an executable | |
1417 | whose e_type member in the ELF header is not ET_DYN. There may | |
1418 | be a time in the future when it is desirable to do relocations | |
1419 | on other types of files as well in which case this condition | |
1420 | should either be removed or modified to accomodate the new file | |
1421 | type. (E.g, an ET_EXEC executable which has been built to be | |
1422 | position-independent could safely be relocated by the OS if | |
1423 | desired. It is true that this violates the ABI, but the ABI | |
1424 | has been known to be bent from time to time.) - Kevin, Nov 2000. ] | |
1425 | */ | |
1426 | ||
1427 | interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); | |
1428 | if (interp_sect == NULL | |
1429 | && (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0 | |
1430 | && bfd_get_start_address (exec_bfd) != pc) | |
1431 | { | |
1432 | struct cleanup *old_chain; | |
1433 | struct section_offsets *new_offsets; | |
1434 | int i, changed; | |
1435 | CORE_ADDR displacement; | |
1436 | ||
1437 | /* It is necessary to relocate the objfile. The amount to | |
1438 | relocate by is simply the address at which we are stopped | |
1439 | minus the starting address from the executable. | |
1440 | ||
1441 | We relocate all of the sections by the same amount. This | |
1442 | behavior is mandated by recent editions of the System V ABI. | |
1443 | According to the System V Application Binary Interface, | |
1444 | Edition 4.1, page 5-5: | |
1445 | ||
1446 | ... Though the system chooses virtual addresses for | |
1447 | individual processes, it maintains the segments' relative | |
1448 | positions. Because position-independent code uses relative | |
1449 | addressesing between segments, the difference between | |
1450 | virtual addresses in memory must match the difference | |
1451 | between virtual addresses in the file. The difference | |
1452 | between the virtual address of any segment in memory and | |
1453 | the corresponding virtual address in the file is thus a | |
1454 | single constant value for any one executable or shared | |
1455 | object in a given process. This difference is the base | |
1456 | address. One use of the base address is to relocate the | |
1457 | memory image of the program during dynamic linking. | |
1458 | ||
1459 | The same language also appears in Edition 4.0 of the System V | |
1460 | ABI and is left unspecified in some of the earlier editions. */ | |
1461 | ||
1462 | displacement = pc - bfd_get_start_address (exec_bfd); | |
1463 | changed = 0; | |
1464 | ||
1465 | new_offsets = xcalloc (sizeof (struct section_offsets), | |
1466 | symfile_objfile->num_sections); | |
b8c9b27d | 1467 | old_chain = make_cleanup (xfree, new_offsets); |
e2a44558 KB |
1468 | |
1469 | for (i = 0; i < symfile_objfile->num_sections; i++) | |
1470 | { | |
1471 | if (displacement != ANOFFSET (symfile_objfile->section_offsets, i)) | |
1472 | changed = 1; | |
1473 | new_offsets->offsets[i] = displacement; | |
1474 | } | |
1475 | ||
1476 | if (changed) | |
1477 | objfile_relocate (symfile_objfile, new_offsets); | |
1478 | ||
1479 | do_cleanups (old_chain); | |
1480 | } | |
1481 | } | |
1482 | ||
13437d4b KB |
1483 | /* |
1484 | ||
1485 | GLOBAL FUNCTION | |
1486 | ||
1487 | svr4_solib_create_inferior_hook -- shared library startup support | |
1488 | ||
1489 | SYNOPSIS | |
1490 | ||
1491 | void svr4_solib_create_inferior_hook() | |
1492 | ||
1493 | DESCRIPTION | |
1494 | ||
1495 | When gdb starts up the inferior, it nurses it along (through the | |
1496 | shell) until it is ready to execute it's first instruction. At this | |
1497 | point, this function gets called via expansion of the macro | |
1498 | SOLIB_CREATE_INFERIOR_HOOK. | |
1499 | ||
1500 | For SunOS executables, this first instruction is typically the | |
1501 | one at "_start", or a similar text label, regardless of whether | |
1502 | the executable is statically or dynamically linked. The runtime | |
1503 | startup code takes care of dynamically linking in any shared | |
1504 | libraries, once gdb allows the inferior to continue. | |
1505 | ||
1506 | For SVR4 executables, this first instruction is either the first | |
1507 | instruction in the dynamic linker (for dynamically linked | |
1508 | executables) or the instruction at "start" for statically linked | |
1509 | executables. For dynamically linked executables, the system | |
1510 | first exec's /lib/libc.so.N, which contains the dynamic linker, | |
1511 | and starts it running. The dynamic linker maps in any needed | |
1512 | shared libraries, maps in the actual user executable, and then | |
1513 | jumps to "start" in the user executable. | |
1514 | ||
1515 | For both SunOS shared libraries, and SVR4 shared libraries, we | |
1516 | can arrange to cooperate with the dynamic linker to discover the | |
1517 | names of shared libraries that are dynamically linked, and the | |
1518 | base addresses to which they are linked. | |
1519 | ||
1520 | This function is responsible for discovering those names and | |
1521 | addresses, and saving sufficient information about them to allow | |
1522 | their symbols to be read at a later time. | |
1523 | ||
1524 | FIXME | |
1525 | ||
1526 | Between enable_break() and disable_break(), this code does not | |
1527 | properly handle hitting breakpoints which the user might have | |
1528 | set in the startup code or in the dynamic linker itself. Proper | |
1529 | handling will probably have to wait until the implementation is | |
1530 | changed to use the "breakpoint handler function" method. | |
1531 | ||
1532 | Also, what if child has exit()ed? Must exit loop somehow. | |
1533 | */ | |
1534 | ||
e2a44558 | 1535 | static void |
13437d4b KB |
1536 | svr4_solib_create_inferior_hook (void) |
1537 | { | |
e2a44558 KB |
1538 | /* Relocate the main executable if necessary. */ |
1539 | svr4_relocate_main_executable (); | |
1540 | ||
13437d4b KB |
1541 | /* If we are using the BKPT_AT_SYMBOL code, then we don't need the base |
1542 | yet. In fact, in the case of a SunOS4 executable being run on | |
1543 | Solaris, we can't get it yet. current_sos will get it when it needs | |
1544 | it. */ | |
1545 | #if !(defined (SVR4_SHARED_LIBS) && defined (BKPT_AT_SYMBOL)) | |
1546 | if ((debug_base = locate_base ()) == 0) | |
1547 | { | |
1548 | /* Can't find the symbol or the executable is statically linked. */ | |
1549 | return; | |
1550 | } | |
1551 | #endif | |
1552 | ||
1553 | if (!enable_break ()) | |
1554 | { | |
1555 | warning ("shared library handler failed to enable breakpoint"); | |
1556 | return; | |
1557 | } | |
1558 | ||
1559 | #if !defined(SVR4_SHARED_LIBS) || defined(_SCO_DS) | |
1560 | /* SCO and SunOS need the loop below, other systems should be using the | |
1561 | special shared library breakpoints and the shared library breakpoint | |
1562 | service routine. | |
1563 | ||
1564 | Now run the target. It will eventually hit the breakpoint, at | |
1565 | which point all of the libraries will have been mapped in and we | |
1566 | can go groveling around in the dynamic linker structures to find | |
1567 | out what we need to know about them. */ | |
1568 | ||
1569 | clear_proceed_status (); | |
1570 | stop_soon_quietly = 1; | |
1571 | stop_signal = TARGET_SIGNAL_0; | |
1572 | do | |
1573 | { | |
39f77062 | 1574 | target_resume (pid_to_ptid (-1), 0, stop_signal); |
13437d4b KB |
1575 | wait_for_inferior (); |
1576 | } | |
1577 | while (stop_signal != TARGET_SIGNAL_TRAP); | |
1578 | stop_soon_quietly = 0; | |
1579 | ||
1580 | #if !defined(_SCO_DS) | |
1581 | /* We are now either at the "mapping complete" breakpoint (or somewhere | |
1582 | else, a condition we aren't prepared to deal with anyway), so adjust | |
1583 | the PC as necessary after a breakpoint, disable the breakpoint, and | |
1584 | add any shared libraries that were mapped in. */ | |
1585 | ||
1586 | if (DECR_PC_AFTER_BREAK) | |
1587 | { | |
1588 | stop_pc -= DECR_PC_AFTER_BREAK; | |
1589 | write_register (PC_REGNUM, stop_pc); | |
1590 | } | |
1591 | ||
1592 | if (!disable_break ()) | |
1593 | { | |
1594 | warning ("shared library handler failed to disable breakpoint"); | |
1595 | } | |
1596 | ||
1597 | if (auto_solib_add) | |
1598 | solib_add ((char *) 0, 0, (struct target_ops *) 0); | |
1599 | #endif /* ! _SCO_DS */ | |
1600 | #endif | |
1601 | } | |
1602 | ||
1603 | static void | |
1604 | svr4_clear_solib (void) | |
1605 | { | |
1606 | debug_base = 0; | |
1607 | } | |
1608 | ||
1609 | static void | |
1610 | svr4_free_so (struct so_list *so) | |
1611 | { | |
b8c9b27d KB |
1612 | xfree (so->lm_info->lm); |
1613 | xfree (so->lm_info); | |
13437d4b KB |
1614 | } |
1615 | ||
749499cb KB |
1616 | static void |
1617 | svr4_relocate_section_addresses (struct so_list *so, | |
1618 | struct section_table *sec) | |
1619 | { | |
1620 | sec->addr += LM_ADDR (so); | |
1621 | sec->endaddr += LM_ADDR (so); | |
1622 | } | |
1623 | ||
21479ded KB |
1624 | void |
1625 | set_solib_svr4_fetch_link_map_offsets (struct link_map_offsets *(*flmo) (void)) | |
1626 | { | |
1627 | fetch_link_map_offsets = flmo; | |
1628 | } | |
1629 | ||
1630 | static void | |
1631 | init_fetch_link_map_offsets (void) | |
1632 | { | |
1633 | set_solib_svr4_fetch_link_map_offsets (default_svr4_fetch_link_map_offsets); | |
1634 | } | |
1635 | ||
13437d4b KB |
1636 | static struct target_so_ops svr4_so_ops; |
1637 | ||
1638 | void | |
1639 | _initialize_svr4_solib (void) | |
1640 | { | |
21479ded KB |
1641 | register_gdbarch_swap (&fetch_link_map_offsets, |
1642 | sizeof (fetch_link_map_offsets), | |
1643 | init_fetch_link_map_offsets); | |
1644 | ||
749499cb | 1645 | svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses; |
13437d4b KB |
1646 | svr4_so_ops.free_so = svr4_free_so; |
1647 | svr4_so_ops.clear_solib = svr4_clear_solib; | |
1648 | svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook; | |
1649 | svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling; | |
1650 | svr4_so_ops.current_sos = svr4_current_sos; | |
1651 | svr4_so_ops.open_symbol_file_object = open_symbol_file_object; | |
d7fa2ae2 | 1652 | svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code; |
13437d4b KB |
1653 | |
1654 | /* FIXME: Don't do this here. *_gdbarch_init() should set so_ops. */ | |
1655 | current_target_so_ops = &svr4_so_ops; | |
1656 | } | |
1657 |