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ab31aa69 | 1 | /* Handle 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 | ||
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23 | #include "defs.h" |
24 | ||
13437d4b | 25 | #include "elf/external.h" |
21479ded | 26 | #include "elf/common.h" |
f7856c8f | 27 | #include "elf/mips.h" |
13437d4b KB |
28 | |
29 | #include "symtab.h" | |
30 | #include "bfd.h" | |
31 | #include "symfile.h" | |
32 | #include "objfiles.h" | |
33 | #include "gdbcore.h" | |
13437d4b | 34 | #include "target.h" |
13437d4b | 35 | #include "inferior.h" |
13437d4b KB |
36 | |
37 | #include "solist.h" | |
38 | #include "solib-svr4.h" | |
39 | ||
21479ded | 40 | #ifndef SVR4_FETCH_LINK_MAP_OFFSETS |
e5e2b9ff | 41 | #define SVR4_FETCH_LINK_MAP_OFFSETS() svr4_fetch_link_map_offsets () |
21479ded KB |
42 | #endif |
43 | ||
e5e2b9ff KB |
44 | static struct link_map_offsets *svr4_fetch_link_map_offsets (void); |
45 | static struct link_map_offsets *legacy_fetch_link_map_offsets (void); | |
1c4dcb57 | 46 | |
e5e2b9ff KB |
47 | /* fetch_link_map_offsets_gdbarch_data is a handle used to obtain the |
48 | architecture specific link map offsets fetching function. */ | |
21479ded | 49 | |
e5e2b9ff | 50 | static struct gdbarch_data *fetch_link_map_offsets_gdbarch_data; |
1c4dcb57 | 51 | |
21479ded KB |
52 | /* legacy_svr4_fetch_link_map_offsets_hook is a pointer to a function |
53 | which is used to fetch link map offsets. It will only be set | |
54 | by solib-legacy.c, if at all. */ | |
e5e2b9ff | 55 | |
21479ded KB |
56 | struct link_map_offsets *(*legacy_svr4_fetch_link_map_offsets_hook)(void) = 0; |
57 | ||
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58 | /* Link map info to include in an allocated so_list entry */ |
59 | ||
60 | struct lm_info | |
61 | { | |
62 | /* Pointer to copy of link map from inferior. The type is char * | |
63 | rather than void *, so that we may use byte offsets to find the | |
64 | various fields without the need for a cast. */ | |
65 | char *lm; | |
66 | }; | |
67 | ||
68 | /* On SVR4 systems, a list of symbols in the dynamic linker where | |
69 | GDB can try to place a breakpoint to monitor shared library | |
70 | events. | |
71 | ||
72 | If none of these symbols are found, or other errors occur, then | |
73 | SVR4 systems will fall back to using a symbol as the "startup | |
74 | mapping complete" breakpoint address. */ | |
75 | ||
13437d4b KB |
76 | static char *solib_break_names[] = |
77 | { | |
78 | "r_debug_state", | |
79 | "_r_debug_state", | |
80 | "_dl_debug_state", | |
81 | "rtld_db_dlactivity", | |
1f72e589 | 82 | "_rtld_debug_state", |
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83 | NULL |
84 | }; | |
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85 | |
86 | #define BKPT_AT_SYMBOL 1 | |
87 | ||
ab31aa69 | 88 | #if defined (BKPT_AT_SYMBOL) |
13437d4b KB |
89 | static char *bkpt_names[] = |
90 | { | |
91 | #ifdef SOLIB_BKPT_NAME | |
92 | SOLIB_BKPT_NAME, /* Prefer configured name if it exists. */ | |
93 | #endif | |
94 | "_start", | |
ad3dcc5c | 95 | "__start", |
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96 | "main", |
97 | NULL | |
98 | }; | |
99 | #endif | |
100 | ||
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101 | static char *main_name_list[] = |
102 | { | |
103 | "main_$main", | |
104 | NULL | |
105 | }; | |
106 | ||
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107 | /* Macro to extract an address from a solib structure. |
108 | When GDB is configured for some 32-bit targets (e.g. Solaris 2.7 | |
109 | sparc), BFD is configured to handle 64-bit targets, so CORE_ADDR is | |
110 | 64 bits. We have to extract only the significant bits of addresses | |
111 | to get the right address when accessing the core file BFD. */ | |
112 | ||
113 | #define SOLIB_EXTRACT_ADDRESS(MEMBER) \ | |
114 | extract_address (&(MEMBER), sizeof (MEMBER)) | |
115 | ||
116 | /* local data declarations */ | |
117 | ||
13437d4b KB |
118 | /* link map access functions */ |
119 | ||
120 | static CORE_ADDR | |
121 | LM_ADDR (struct so_list *so) | |
122 | { | |
123 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
124 | ||
58bc91c9 MH |
125 | return (CORE_ADDR) extract_signed_integer (so->lm_info->lm + lmo->l_addr_offset, |
126 | lmo->l_addr_size); | |
13437d4b KB |
127 | } |
128 | ||
129 | static CORE_ADDR | |
130 | LM_NEXT (struct so_list *so) | |
131 | { | |
132 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
133 | ||
134 | return extract_address (so->lm_info->lm + lmo->l_next_offset, lmo->l_next_size); | |
135 | } | |
136 | ||
137 | static CORE_ADDR | |
138 | LM_NAME (struct so_list *so) | |
139 | { | |
140 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
141 | ||
142 | return extract_address (so->lm_info->lm + lmo->l_name_offset, lmo->l_name_size); | |
143 | } | |
144 | ||
13437d4b KB |
145 | static int |
146 | IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list *so) | |
147 | { | |
148 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
149 | ||
150 | return extract_address (so->lm_info->lm + lmo->l_prev_offset, | |
151 | lmo->l_prev_size) == 0; | |
152 | } | |
153 | ||
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154 | static CORE_ADDR debug_base; /* Base of dynamic linker structures */ |
155 | static CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */ | |
156 | ||
157 | /* Local function prototypes */ | |
158 | ||
159 | static int match_main (char *); | |
160 | ||
13437d4b KB |
161 | static CORE_ADDR bfd_lookup_symbol (bfd *, char *); |
162 | ||
163 | /* | |
164 | ||
165 | LOCAL FUNCTION | |
166 | ||
167 | bfd_lookup_symbol -- lookup the value for a specific symbol | |
168 | ||
169 | SYNOPSIS | |
170 | ||
171 | CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname) | |
172 | ||
173 | DESCRIPTION | |
174 | ||
175 | An expensive way to lookup the value of a single symbol for | |
176 | bfd's that are only temporary anyway. This is used by the | |
177 | shared library support to find the address of the debugger | |
178 | interface structures in the shared library. | |
179 | ||
180 | Note that 0 is specifically allowed as an error return (no | |
181 | such symbol). | |
182 | */ | |
183 | ||
184 | static CORE_ADDR | |
185 | bfd_lookup_symbol (bfd *abfd, char *symname) | |
186 | { | |
435b259c | 187 | long storage_needed; |
13437d4b KB |
188 | asymbol *sym; |
189 | asymbol **symbol_table; | |
190 | unsigned int number_of_symbols; | |
191 | unsigned int i; | |
192 | struct cleanup *back_to; | |
193 | CORE_ADDR symaddr = 0; | |
194 | ||
195 | storage_needed = bfd_get_symtab_upper_bound (abfd); | |
196 | ||
197 | if (storage_needed > 0) | |
198 | { | |
199 | symbol_table = (asymbol **) xmalloc (storage_needed); | |
b8c9b27d | 200 | back_to = make_cleanup (xfree, (PTR) symbol_table); |
13437d4b KB |
201 | number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); |
202 | ||
203 | for (i = 0; i < number_of_symbols; i++) | |
204 | { | |
205 | sym = *symbol_table++; | |
206 | if (STREQ (sym->name, symname)) | |
207 | { | |
208 | /* Bfd symbols are section relative. */ | |
209 | symaddr = sym->value + sym->section->vma; | |
210 | break; | |
211 | } | |
212 | } | |
213 | do_cleanups (back_to); | |
214 | } | |
215 | ||
216 | if (symaddr) | |
217 | return symaddr; | |
218 | ||
219 | /* On FreeBSD, the dynamic linker is stripped by default. So we'll | |
220 | have to check the dynamic string table too. */ | |
221 | ||
222 | storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd); | |
223 | ||
224 | if (storage_needed > 0) | |
225 | { | |
226 | symbol_table = (asymbol **) xmalloc (storage_needed); | |
b8c9b27d | 227 | back_to = make_cleanup (xfree, (PTR) symbol_table); |
13437d4b KB |
228 | number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table); |
229 | ||
230 | for (i = 0; i < number_of_symbols; i++) | |
231 | { | |
232 | sym = *symbol_table++; | |
233 | if (STREQ (sym->name, symname)) | |
234 | { | |
235 | /* Bfd symbols are section relative. */ | |
236 | symaddr = sym->value + sym->section->vma; | |
237 | break; | |
238 | } | |
239 | } | |
240 | do_cleanups (back_to); | |
241 | } | |
242 | ||
243 | return symaddr; | |
244 | } | |
245 | ||
246 | #ifdef HANDLE_SVR4_EXEC_EMULATORS | |
247 | ||
248 | /* | |
249 | Solaris BCP (the part of Solaris which allows it to run SunOS4 | |
250 | a.out files) throws in another wrinkle. Solaris does not fill | |
251 | in the usual a.out link map structures when running BCP programs, | |
252 | the only way to get at them is via groping around in the dynamic | |
253 | linker. | |
254 | The dynamic linker and it's structures are located in the shared | |
255 | C library, which gets run as the executable's "interpreter" by | |
256 | the kernel. | |
257 | ||
258 | Note that we can assume nothing about the process state at the time | |
259 | we need to find these structures. We may be stopped on the first | |
260 | instruction of the interpreter (C shared library), the first | |
261 | instruction of the executable itself, or somewhere else entirely | |
262 | (if we attached to the process for example). | |
263 | */ | |
264 | ||
265 | static char *debug_base_symbols[] = | |
266 | { | |
267 | "r_debug", /* Solaris 2.3 */ | |
268 | "_r_debug", /* Solaris 2.1, 2.2 */ | |
269 | NULL | |
270 | }; | |
271 | ||
272 | static int look_for_base (int, CORE_ADDR); | |
273 | ||
274 | /* | |
275 | ||
276 | LOCAL FUNCTION | |
277 | ||
278 | look_for_base -- examine file for each mapped address segment | |
279 | ||
280 | SYNOPSYS | |
281 | ||
282 | static int look_for_base (int fd, CORE_ADDR baseaddr) | |
283 | ||
284 | DESCRIPTION | |
285 | ||
286 | This function is passed to proc_iterate_over_mappings, which | |
287 | causes it to get called once for each mapped address space, with | |
288 | an open file descriptor for the file mapped to that space, and the | |
289 | base address of that mapped space. | |
290 | ||
291 | Our job is to find the debug base symbol in the file that this | |
292 | fd is open on, if it exists, and if so, initialize the dynamic | |
293 | linker structure base address debug_base. | |
294 | ||
295 | Note that this is a computationally expensive proposition, since | |
296 | we basically have to open a bfd on every call, so we specifically | |
297 | avoid opening the exec file. | |
298 | */ | |
299 | ||
300 | static int | |
301 | look_for_base (int fd, CORE_ADDR baseaddr) | |
302 | { | |
303 | bfd *interp_bfd; | |
304 | CORE_ADDR address = 0; | |
305 | char **symbolp; | |
306 | ||
307 | /* If the fd is -1, then there is no file that corresponds to this | |
308 | mapped memory segment, so skip it. Also, if the fd corresponds | |
309 | to the exec file, skip it as well. */ | |
310 | ||
311 | if (fd == -1 | |
312 | || (exec_bfd != NULL | |
313 | && fdmatch (fileno ((FILE *) (exec_bfd->iostream)), fd))) | |
314 | { | |
315 | return (0); | |
316 | } | |
317 | ||
318 | /* Try to open whatever random file this fd corresponds to. Note that | |
319 | we have no way currently to find the filename. Don't gripe about | |
320 | any problems we might have, just fail. */ | |
321 | ||
322 | if ((interp_bfd = bfd_fdopenr ("unnamed", gnutarget, fd)) == NULL) | |
323 | { | |
324 | return (0); | |
325 | } | |
326 | if (!bfd_check_format (interp_bfd, bfd_object)) | |
327 | { | |
328 | /* FIXME-leak: on failure, might not free all memory associated with | |
329 | interp_bfd. */ | |
330 | bfd_close (interp_bfd); | |
331 | return (0); | |
332 | } | |
333 | ||
334 | /* Now try to find our debug base symbol in this file, which we at | |
335 | least know to be a valid ELF executable or shared library. */ | |
336 | ||
337 | for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++) | |
338 | { | |
339 | address = bfd_lookup_symbol (interp_bfd, *symbolp); | |
340 | if (address != 0) | |
341 | { | |
342 | break; | |
343 | } | |
344 | } | |
345 | if (address == 0) | |
346 | { | |
347 | /* FIXME-leak: on failure, might not free all memory associated with | |
348 | interp_bfd. */ | |
349 | bfd_close (interp_bfd); | |
350 | return (0); | |
351 | } | |
352 | ||
353 | /* Eureka! We found the symbol. But now we may need to relocate it | |
354 | by the base address. If the symbol's value is less than the base | |
355 | address of the shared library, then it hasn't yet been relocated | |
356 | by the dynamic linker, and we have to do it ourself. FIXME: Note | |
357 | that we make the assumption that the first segment that corresponds | |
358 | to the shared library has the base address to which the library | |
359 | was relocated. */ | |
360 | ||
361 | if (address < baseaddr) | |
362 | { | |
363 | address += baseaddr; | |
364 | } | |
365 | debug_base = address; | |
366 | /* FIXME-leak: on failure, might not free all memory associated with | |
367 | interp_bfd. */ | |
368 | bfd_close (interp_bfd); | |
369 | return (1); | |
370 | } | |
371 | #endif /* HANDLE_SVR4_EXEC_EMULATORS */ | |
372 | ||
373 | /* | |
374 | ||
375 | LOCAL FUNCTION | |
376 | ||
377 | elf_locate_base -- locate the base address of dynamic linker structs | |
378 | for SVR4 elf targets. | |
379 | ||
380 | SYNOPSIS | |
381 | ||
382 | CORE_ADDR elf_locate_base (void) | |
383 | ||
384 | DESCRIPTION | |
385 | ||
386 | For SVR4 elf targets the address of the dynamic linker's runtime | |
387 | structure is contained within the dynamic info section in the | |
388 | executable file. The dynamic section is also mapped into the | |
389 | inferior address space. Because the runtime loader fills in the | |
390 | real address before starting the inferior, we have to read in the | |
391 | dynamic info section from the inferior address space. | |
392 | If there are any errors while trying to find the address, we | |
393 | silently return 0, otherwise the found address is returned. | |
394 | ||
395 | */ | |
396 | ||
397 | static CORE_ADDR | |
398 | elf_locate_base (void) | |
399 | { | |
400 | sec_ptr dyninfo_sect; | |
401 | int dyninfo_sect_size; | |
402 | CORE_ADDR dyninfo_addr; | |
403 | char *buf; | |
404 | char *bufend; | |
405 | int arch_size; | |
406 | ||
407 | /* Find the start address of the .dynamic section. */ | |
408 | dyninfo_sect = bfd_get_section_by_name (exec_bfd, ".dynamic"); | |
409 | if (dyninfo_sect == NULL) | |
410 | return 0; | |
411 | dyninfo_addr = bfd_section_vma (exec_bfd, dyninfo_sect); | |
412 | ||
413 | /* Read in .dynamic section, silently ignore errors. */ | |
414 | dyninfo_sect_size = bfd_section_size (exec_bfd, dyninfo_sect); | |
415 | buf = alloca (dyninfo_sect_size); | |
416 | if (target_read_memory (dyninfo_addr, buf, dyninfo_sect_size)) | |
417 | return 0; | |
418 | ||
419 | /* Find the DT_DEBUG entry in the the .dynamic section. | |
420 | For mips elf we look for DT_MIPS_RLD_MAP, mips elf apparently has | |
421 | no DT_DEBUG entries. */ | |
422 | ||
423 | arch_size = bfd_get_arch_size (exec_bfd); | |
424 | if (arch_size == -1) /* failure */ | |
425 | return 0; | |
426 | ||
427 | if (arch_size == 32) | |
428 | { /* 32-bit elf */ | |
429 | for (bufend = buf + dyninfo_sect_size; | |
430 | buf < bufend; | |
431 | buf += sizeof (Elf32_External_Dyn)) | |
432 | { | |
433 | Elf32_External_Dyn *x_dynp = (Elf32_External_Dyn *) buf; | |
434 | long dyn_tag; | |
435 | CORE_ADDR dyn_ptr; | |
436 | ||
437 | dyn_tag = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_tag); | |
438 | if (dyn_tag == DT_NULL) | |
439 | break; | |
440 | else if (dyn_tag == DT_DEBUG) | |
441 | { | |
442 | dyn_ptr = bfd_h_get_32 (exec_bfd, | |
443 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
444 | return dyn_ptr; | |
445 | } | |
13437d4b KB |
446 | else if (dyn_tag == DT_MIPS_RLD_MAP) |
447 | { | |
448 | char *pbuf; | |
449 | ||
450 | pbuf = alloca (TARGET_PTR_BIT / HOST_CHAR_BIT); | |
451 | /* DT_MIPS_RLD_MAP contains a pointer to the address | |
452 | of the dynamic link structure. */ | |
453 | dyn_ptr = bfd_h_get_32 (exec_bfd, | |
454 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
455 | if (target_read_memory (dyn_ptr, pbuf, sizeof (pbuf))) | |
456 | return 0; | |
457 | return extract_unsigned_integer (pbuf, sizeof (pbuf)); | |
458 | } | |
13437d4b KB |
459 | } |
460 | } | |
461 | else /* 64-bit elf */ | |
462 | { | |
463 | for (bufend = buf + dyninfo_sect_size; | |
464 | buf < bufend; | |
465 | buf += sizeof (Elf64_External_Dyn)) | |
466 | { | |
467 | Elf64_External_Dyn *x_dynp = (Elf64_External_Dyn *) buf; | |
468 | long dyn_tag; | |
469 | CORE_ADDR dyn_ptr; | |
470 | ||
471 | dyn_tag = bfd_h_get_64 (exec_bfd, (bfd_byte *) x_dynp->d_tag); | |
472 | if (dyn_tag == DT_NULL) | |
473 | break; | |
474 | else if (dyn_tag == DT_DEBUG) | |
475 | { | |
476 | dyn_ptr = bfd_h_get_64 (exec_bfd, | |
477 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
478 | return dyn_ptr; | |
479 | } | |
480 | } | |
481 | } | |
482 | ||
483 | /* DT_DEBUG entry not found. */ | |
484 | return 0; | |
485 | } | |
486 | ||
13437d4b KB |
487 | /* |
488 | ||
489 | LOCAL FUNCTION | |
490 | ||
491 | locate_base -- locate the base address of dynamic linker structs | |
492 | ||
493 | SYNOPSIS | |
494 | ||
495 | CORE_ADDR locate_base (void) | |
496 | ||
497 | DESCRIPTION | |
498 | ||
499 | For both the SunOS and SVR4 shared library implementations, if the | |
500 | inferior executable has been linked dynamically, there is a single | |
501 | address somewhere in the inferior's data space which is the key to | |
502 | locating all of the dynamic linker's runtime structures. This | |
503 | address is the value of the debug base symbol. The job of this | |
504 | function is to find and return that address, or to return 0 if there | |
505 | is no such address (the executable is statically linked for example). | |
506 | ||
507 | For SunOS, the job is almost trivial, since the dynamic linker and | |
508 | all of it's structures are statically linked to the executable at | |
509 | link time. Thus the symbol for the address we are looking for has | |
510 | already been added to the minimal symbol table for the executable's | |
511 | objfile at the time the symbol file's symbols were read, and all we | |
512 | have to do is look it up there. Note that we explicitly do NOT want | |
513 | to find the copies in the shared library. | |
514 | ||
515 | The SVR4 version is a bit more complicated because the address | |
516 | is contained somewhere in the dynamic info section. We have to go | |
517 | to a lot more work to discover the address of the debug base symbol. | |
518 | Because of this complexity, we cache the value we find and return that | |
519 | value on subsequent invocations. Note there is no copy in the | |
520 | executable symbol tables. | |
521 | ||
522 | */ | |
523 | ||
524 | static CORE_ADDR | |
525 | locate_base (void) | |
526 | { | |
13437d4b KB |
527 | /* Check to see if we have a currently valid address, and if so, avoid |
528 | doing all this work again and just return the cached address. If | |
529 | we have no cached address, try to locate it in the dynamic info | |
530 | section for ELF executables. */ | |
531 | ||
532 | if (debug_base == 0) | |
533 | { | |
534 | if (exec_bfd != NULL | |
535 | && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) | |
536 | debug_base = elf_locate_base (); | |
537 | #ifdef HANDLE_SVR4_EXEC_EMULATORS | |
538 | /* Try it the hard way for emulated executables. */ | |
39f77062 | 539 | else if (!ptid_equal (inferior_ptid, null_ptid) && target_has_execution) |
13437d4b KB |
540 | proc_iterate_over_mappings (look_for_base); |
541 | #endif | |
542 | } | |
543 | return (debug_base); | |
13437d4b KB |
544 | } |
545 | ||
546 | /* | |
547 | ||
548 | LOCAL FUNCTION | |
549 | ||
550 | first_link_map_member -- locate first member in dynamic linker's map | |
551 | ||
552 | SYNOPSIS | |
553 | ||
554 | static CORE_ADDR first_link_map_member (void) | |
555 | ||
556 | DESCRIPTION | |
557 | ||
558 | Find the first element in the inferior's dynamic link map, and | |
559 | return its address in the inferior. This function doesn't copy the | |
560 | link map entry itself into our address space; current_sos actually | |
561 | does the reading. */ | |
562 | ||
563 | static CORE_ADDR | |
564 | first_link_map_member (void) | |
565 | { | |
566 | CORE_ADDR lm = 0; | |
13437d4b KB |
567 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); |
568 | char *r_map_buf = xmalloc (lmo->r_map_size); | |
b8c9b27d | 569 | struct cleanup *cleanups = make_cleanup (xfree, r_map_buf); |
13437d4b KB |
570 | |
571 | read_memory (debug_base + lmo->r_map_offset, r_map_buf, lmo->r_map_size); | |
572 | ||
573 | lm = extract_address (r_map_buf, lmo->r_map_size); | |
574 | ||
575 | /* FIXME: Perhaps we should validate the info somehow, perhaps by | |
576 | checking r_version for a known version number, or r_state for | |
577 | RT_CONSISTENT. */ | |
578 | ||
579 | do_cleanups (cleanups); | |
580 | ||
13437d4b KB |
581 | return (lm); |
582 | } | |
583 | ||
13437d4b KB |
584 | /* |
585 | ||
586 | LOCAL FUNCTION | |
587 | ||
588 | open_symbol_file_object | |
589 | ||
590 | SYNOPSIS | |
591 | ||
592 | void open_symbol_file_object (void *from_tty) | |
593 | ||
594 | DESCRIPTION | |
595 | ||
596 | If no open symbol file, attempt to locate and open the main symbol | |
597 | file. On SVR4 systems, this is the first link map entry. If its | |
598 | name is here, we can open it. Useful when attaching to a process | |
599 | without first loading its symbol file. | |
600 | ||
601 | If FROM_TTYP dereferences to a non-zero integer, allow messages to | |
602 | be printed. This parameter is a pointer rather than an int because | |
603 | open_symbol_file_object() is called via catch_errors() and | |
604 | catch_errors() requires a pointer argument. */ | |
605 | ||
606 | static int | |
607 | open_symbol_file_object (void *from_ttyp) | |
608 | { | |
609 | CORE_ADDR lm, l_name; | |
610 | char *filename; | |
611 | int errcode; | |
612 | int from_tty = *(int *)from_ttyp; | |
613 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
614 | char *l_name_buf = xmalloc (lmo->l_name_size); | |
b8c9b27d | 615 | struct cleanup *cleanups = make_cleanup (xfree, l_name_buf); |
13437d4b KB |
616 | |
617 | if (symfile_objfile) | |
618 | if (!query ("Attempt to reload symbols from process? ")) | |
619 | return 0; | |
620 | ||
621 | if ((debug_base = locate_base ()) == 0) | |
622 | return 0; /* failed somehow... */ | |
623 | ||
624 | /* First link map member should be the executable. */ | |
625 | if ((lm = first_link_map_member ()) == 0) | |
626 | return 0; /* failed somehow... */ | |
627 | ||
628 | /* Read address of name from target memory to GDB. */ | |
629 | read_memory (lm + lmo->l_name_offset, l_name_buf, lmo->l_name_size); | |
630 | ||
631 | /* Convert the address to host format. */ | |
632 | l_name = extract_address (l_name_buf, lmo->l_name_size); | |
633 | ||
634 | /* Free l_name_buf. */ | |
635 | do_cleanups (cleanups); | |
636 | ||
637 | if (l_name == 0) | |
638 | return 0; /* No filename. */ | |
639 | ||
640 | /* Now fetch the filename from target memory. */ | |
641 | target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode); | |
642 | ||
643 | if (errcode) | |
644 | { | |
645 | warning ("failed to read exec filename from attached file: %s", | |
646 | safe_strerror (errcode)); | |
647 | return 0; | |
648 | } | |
649 | ||
b8c9b27d | 650 | make_cleanup (xfree, filename); |
13437d4b | 651 | /* Have a pathname: read the symbol file. */ |
1adeb98a | 652 | symbol_file_add_main (filename, from_tty); |
13437d4b KB |
653 | |
654 | return 1; | |
655 | } | |
13437d4b KB |
656 | |
657 | /* LOCAL FUNCTION | |
658 | ||
659 | current_sos -- build a list of currently loaded shared objects | |
660 | ||
661 | SYNOPSIS | |
662 | ||
663 | struct so_list *current_sos () | |
664 | ||
665 | DESCRIPTION | |
666 | ||
667 | Build a list of `struct so_list' objects describing the shared | |
668 | objects currently loaded in the inferior. This list does not | |
669 | include an entry for the main executable file. | |
670 | ||
671 | Note that we only gather information directly available from the | |
672 | inferior --- we don't examine any of the shared library files | |
673 | themselves. The declaration of `struct so_list' says which fields | |
674 | we provide values for. */ | |
675 | ||
676 | static struct so_list * | |
677 | svr4_current_sos (void) | |
678 | { | |
679 | CORE_ADDR lm; | |
680 | struct so_list *head = 0; | |
681 | struct so_list **link_ptr = &head; | |
682 | ||
683 | /* Make sure we've looked up the inferior's dynamic linker's base | |
684 | structure. */ | |
685 | if (! debug_base) | |
686 | { | |
687 | debug_base = locate_base (); | |
688 | ||
689 | /* If we can't find the dynamic linker's base structure, this | |
690 | must not be a dynamically linked executable. Hmm. */ | |
691 | if (! debug_base) | |
692 | return 0; | |
693 | } | |
694 | ||
695 | /* Walk the inferior's link map list, and build our list of | |
696 | `struct so_list' nodes. */ | |
697 | lm = first_link_map_member (); | |
698 | while (lm) | |
699 | { | |
700 | struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS (); | |
701 | struct so_list *new | |
702 | = (struct so_list *) xmalloc (sizeof (struct so_list)); | |
b8c9b27d | 703 | struct cleanup *old_chain = make_cleanup (xfree, new); |
13437d4b KB |
704 | |
705 | memset (new, 0, sizeof (*new)); | |
706 | ||
707 | new->lm_info = xmalloc (sizeof (struct lm_info)); | |
b8c9b27d | 708 | make_cleanup (xfree, new->lm_info); |
13437d4b KB |
709 | |
710 | new->lm_info->lm = xmalloc (lmo->link_map_size); | |
b8c9b27d | 711 | make_cleanup (xfree, new->lm_info->lm); |
13437d4b KB |
712 | memset (new->lm_info->lm, 0, lmo->link_map_size); |
713 | ||
714 | read_memory (lm, new->lm_info->lm, lmo->link_map_size); | |
715 | ||
716 | lm = LM_NEXT (new); | |
717 | ||
718 | /* For SVR4 versions, the first entry in the link map is for the | |
719 | inferior executable, so we must ignore it. For some versions of | |
720 | SVR4, it has no name. For others (Solaris 2.3 for example), it | |
721 | does have a name, so we can no longer use a missing name to | |
722 | decide when to ignore it. */ | |
723 | if (IGNORE_FIRST_LINK_MAP_ENTRY (new)) | |
724 | free_so (new); | |
725 | else | |
726 | { | |
727 | int errcode; | |
728 | char *buffer; | |
729 | ||
730 | /* Extract this shared object's name. */ | |
731 | target_read_string (LM_NAME (new), &buffer, | |
732 | SO_NAME_MAX_PATH_SIZE - 1, &errcode); | |
733 | if (errcode != 0) | |
734 | { | |
735 | warning ("current_sos: Can't read pathname for load map: %s\n", | |
736 | safe_strerror (errcode)); | |
737 | } | |
738 | else | |
739 | { | |
740 | strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1); | |
741 | new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; | |
b8c9b27d | 742 | xfree (buffer); |
13437d4b KB |
743 | strcpy (new->so_original_name, new->so_name); |
744 | } | |
745 | ||
746 | /* If this entry has no name, or its name matches the name | |
747 | for the main executable, don't include it in the list. */ | |
748 | if (! new->so_name[0] | |
749 | || match_main (new->so_name)) | |
750 | free_so (new); | |
751 | else | |
752 | { | |
753 | new->next = 0; | |
754 | *link_ptr = new; | |
755 | link_ptr = &new->next; | |
756 | } | |
757 | } | |
758 | ||
759 | discard_cleanups (old_chain); | |
760 | } | |
761 | ||
762 | return head; | |
763 | } | |
764 | ||
765 | ||
766 | /* On some systems, the only way to recognize the link map entry for | |
767 | the main executable file is by looking at its name. Return | |
768 | non-zero iff SONAME matches one of the known main executable names. */ | |
769 | ||
770 | static int | |
771 | match_main (char *soname) | |
772 | { | |
773 | char **mainp; | |
774 | ||
775 | for (mainp = main_name_list; *mainp != NULL; mainp++) | |
776 | { | |
777 | if (strcmp (soname, *mainp) == 0) | |
778 | return (1); | |
779 | } | |
780 | ||
781 | return (0); | |
782 | } | |
783 | ||
13437d4b KB |
784 | /* Return 1 if PC lies in the dynamic symbol resolution code of the |
785 | SVR4 run time loader. */ | |
13437d4b KB |
786 | static CORE_ADDR interp_text_sect_low; |
787 | static CORE_ADDR interp_text_sect_high; | |
788 | static CORE_ADDR interp_plt_sect_low; | |
789 | static CORE_ADDR interp_plt_sect_high; | |
790 | ||
d7fa2ae2 KB |
791 | static int |
792 | svr4_in_dynsym_resolve_code (CORE_ADDR pc) | |
13437d4b KB |
793 | { |
794 | return ((pc >= interp_text_sect_low && pc < interp_text_sect_high) | |
795 | || (pc >= interp_plt_sect_low && pc < interp_plt_sect_high) | |
796 | || in_plt_section (pc, NULL)); | |
797 | } | |
13437d4b | 798 | |
13437d4b KB |
799 | |
800 | /* | |
801 | ||
802 | LOCAL FUNCTION | |
803 | ||
804 | enable_break -- arrange for dynamic linker to hit breakpoint | |
805 | ||
806 | SYNOPSIS | |
807 | ||
808 | int enable_break (void) | |
809 | ||
810 | DESCRIPTION | |
811 | ||
812 | Both the SunOS and the SVR4 dynamic linkers have, as part of their | |
813 | debugger interface, support for arranging for the inferior to hit | |
814 | a breakpoint after mapping in the shared libraries. This function | |
815 | enables that breakpoint. | |
816 | ||
817 | For SunOS, there is a special flag location (in_debugger) which we | |
818 | set to 1. When the dynamic linker sees this flag set, it will set | |
819 | a breakpoint at a location known only to itself, after saving the | |
820 | original contents of that place and the breakpoint address itself, | |
821 | in it's own internal structures. When we resume the inferior, it | |
822 | will eventually take a SIGTRAP when it runs into the breakpoint. | |
823 | We handle this (in a different place) by restoring the contents of | |
824 | the breakpointed location (which is only known after it stops), | |
825 | chasing around to locate the shared libraries that have been | |
826 | loaded, then resuming. | |
827 | ||
828 | For SVR4, the debugger interface structure contains a member (r_brk) | |
829 | which is statically initialized at the time the shared library is | |
830 | built, to the offset of a function (_r_debug_state) which is guaran- | |
831 | teed to be called once before mapping in a library, and again when | |
832 | the mapping is complete. At the time we are examining this member, | |
833 | it contains only the unrelocated offset of the function, so we have | |
834 | to do our own relocation. Later, when the dynamic linker actually | |
835 | runs, it relocates r_brk to be the actual address of _r_debug_state(). | |
836 | ||
837 | The debugger interface structure also contains an enumeration which | |
838 | is set to either RT_ADD or RT_DELETE prior to changing the mapping, | |
839 | depending upon whether or not the library is being mapped or unmapped, | |
840 | and then set to RT_CONSISTENT after the library is mapped/unmapped. | |
841 | */ | |
842 | ||
843 | static int | |
844 | enable_break (void) | |
845 | { | |
846 | int success = 0; | |
847 | ||
13437d4b KB |
848 | #ifdef BKPT_AT_SYMBOL |
849 | ||
850 | struct minimal_symbol *msymbol; | |
851 | char **bkpt_namep; | |
852 | asection *interp_sect; | |
853 | ||
854 | /* First, remove all the solib event breakpoints. Their addresses | |
855 | may have changed since the last time we ran the program. */ | |
856 | remove_solib_event_breakpoints (); | |
857 | ||
13437d4b KB |
858 | interp_text_sect_low = interp_text_sect_high = 0; |
859 | interp_plt_sect_low = interp_plt_sect_high = 0; | |
860 | ||
861 | /* Find the .interp section; if not found, warn the user and drop | |
862 | into the old breakpoint at symbol code. */ | |
863 | interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); | |
864 | if (interp_sect) | |
865 | { | |
866 | unsigned int interp_sect_size; | |
867 | char *buf; | |
8ad2fcde KB |
868 | CORE_ADDR load_addr = 0; |
869 | int load_addr_found = 0; | |
870 | struct so_list *inferior_sos; | |
e4f7b8c8 MS |
871 | bfd *tmp_bfd = NULL; |
872 | int tmp_fd = -1; | |
873 | char *tmp_pathname = NULL; | |
13437d4b KB |
874 | CORE_ADDR sym_addr = 0; |
875 | ||
876 | /* Read the contents of the .interp section into a local buffer; | |
877 | the contents specify the dynamic linker this program uses. */ | |
878 | interp_sect_size = bfd_section_size (exec_bfd, interp_sect); | |
879 | buf = alloca (interp_sect_size); | |
880 | bfd_get_section_contents (exec_bfd, interp_sect, | |
881 | buf, 0, interp_sect_size); | |
882 | ||
883 | /* Now we need to figure out where the dynamic linker was | |
884 | loaded so that we can load its symbols and place a breakpoint | |
885 | in the dynamic linker itself. | |
886 | ||
887 | This address is stored on the stack. However, I've been unable | |
888 | to find any magic formula to find it for Solaris (appears to | |
889 | be trivial on GNU/Linux). Therefore, we have to try an alternate | |
890 | mechanism to find the dynamic linker's base address. */ | |
e4f7b8c8 MS |
891 | |
892 | tmp_fd = solib_open (buf, &tmp_pathname); | |
893 | if (tmp_fd >= 0) | |
894 | tmp_bfd = bfd_fdopenr (tmp_pathname, gnutarget, tmp_fd); | |
895 | ||
13437d4b KB |
896 | if (tmp_bfd == NULL) |
897 | goto bkpt_at_symbol; | |
898 | ||
899 | /* Make sure the dynamic linker's really a useful object. */ | |
900 | if (!bfd_check_format (tmp_bfd, bfd_object)) | |
901 | { | |
902 | warning ("Unable to grok dynamic linker %s as an object file", buf); | |
903 | bfd_close (tmp_bfd); | |
904 | goto bkpt_at_symbol; | |
905 | } | |
906 | ||
8ad2fcde KB |
907 | /* If the entry in _DYNAMIC for the dynamic linker has already |
908 | been filled in, we can read its base address from there. */ | |
909 | inferior_sos = svr4_current_sos (); | |
910 | if (inferior_sos) | |
911 | { | |
912 | /* Connected to a running target. Update our shared library table. */ | |
990f9fe3 | 913 | solib_add (NULL, 0, NULL, auto_solib_add); |
8ad2fcde KB |
914 | } |
915 | while (inferior_sos) | |
916 | { | |
917 | if (strcmp (buf, inferior_sos->so_original_name) == 0) | |
918 | { | |
919 | load_addr_found = 1; | |
920 | load_addr = LM_ADDR (inferior_sos); | |
921 | break; | |
922 | } | |
923 | inferior_sos = inferior_sos->next; | |
924 | } | |
925 | ||
926 | /* Otherwise we find the dynamic linker's base address by examining | |
927 | the current pc (which should point at the entry point for the | |
928 | dynamic linker) and subtracting the offset of the entry point. */ | |
929 | if (!load_addr_found) | |
930 | load_addr = read_pc () - tmp_bfd->start_address; | |
13437d4b KB |
931 | |
932 | /* Record the relocated start and end address of the dynamic linker | |
d7fa2ae2 | 933 | text and plt section for svr4_in_dynsym_resolve_code. */ |
13437d4b KB |
934 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
935 | if (interp_sect) | |
936 | { | |
937 | interp_text_sect_low = | |
938 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
939 | interp_text_sect_high = | |
940 | interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
941 | } | |
942 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); | |
943 | if (interp_sect) | |
944 | { | |
945 | interp_plt_sect_low = | |
946 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
947 | interp_plt_sect_high = | |
948 | interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
949 | } | |
950 | ||
951 | /* Now try to set a breakpoint in the dynamic linker. */ | |
952 | for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) | |
953 | { | |
954 | sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep); | |
955 | if (sym_addr != 0) | |
956 | break; | |
957 | } | |
958 | ||
959 | /* We're done with the temporary bfd. */ | |
960 | bfd_close (tmp_bfd); | |
961 | ||
962 | if (sym_addr != 0) | |
963 | { | |
964 | create_solib_event_breakpoint (load_addr + sym_addr); | |
965 | return 1; | |
966 | } | |
967 | ||
968 | /* For whatever reason we couldn't set a breakpoint in the dynamic | |
969 | linker. Warn and drop into the old code. */ | |
970 | bkpt_at_symbol: | |
971 | warning ("Unable to find dynamic linker breakpoint function.\nGDB will be unable to debug shared library initializers\nand track explicitly loaded dynamic code."); | |
972 | } | |
13437d4b KB |
973 | |
974 | /* Scan through the list of symbols, trying to look up the symbol and | |
975 | set a breakpoint there. Terminate loop when we/if we succeed. */ | |
976 | ||
977 | breakpoint_addr = 0; | |
978 | for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++) | |
979 | { | |
980 | msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); | |
981 | if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) | |
982 | { | |
983 | create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol)); | |
984 | return 1; | |
985 | } | |
986 | } | |
987 | ||
988 | /* Nothing good happened. */ | |
989 | success = 0; | |
990 | ||
991 | #endif /* BKPT_AT_SYMBOL */ | |
992 | ||
13437d4b KB |
993 | return (success); |
994 | } | |
995 | ||
996 | /* | |
997 | ||
998 | LOCAL FUNCTION | |
999 | ||
1000 | special_symbol_handling -- additional shared library symbol handling | |
1001 | ||
1002 | SYNOPSIS | |
1003 | ||
1004 | void special_symbol_handling () | |
1005 | ||
1006 | DESCRIPTION | |
1007 | ||
1008 | Once the symbols from a shared object have been loaded in the usual | |
1009 | way, we are called to do any system specific symbol handling that | |
1010 | is needed. | |
1011 | ||
ab31aa69 | 1012 | For SunOS4, this consisted of grunging around in the dynamic |
13437d4b KB |
1013 | linkers structures to find symbol definitions for "common" symbols |
1014 | and adding them to the minimal symbol table for the runtime common | |
1015 | objfile. | |
1016 | ||
ab31aa69 KB |
1017 | However, for SVR4, there's nothing to do. |
1018 | ||
13437d4b KB |
1019 | */ |
1020 | ||
1021 | static void | |
1022 | svr4_special_symbol_handling (void) | |
1023 | { | |
13437d4b KB |
1024 | } |
1025 | ||
e2a44558 KB |
1026 | /* Relocate the main executable. This function should be called upon |
1027 | stopping the inferior process at the entry point to the program. | |
1028 | The entry point from BFD is compared to the PC and if they are | |
1029 | different, the main executable is relocated by the proper amount. | |
1030 | ||
1031 | As written it will only attempt to relocate executables which | |
1032 | lack interpreter sections. It seems likely that only dynamic | |
1033 | linker executables will get relocated, though it should work | |
1034 | properly for a position-independent static executable as well. */ | |
1035 | ||
1036 | static void | |
1037 | svr4_relocate_main_executable (void) | |
1038 | { | |
1039 | asection *interp_sect; | |
1040 | CORE_ADDR pc = read_pc (); | |
1041 | ||
1042 | /* Decide if the objfile needs to be relocated. As indicated above, | |
1043 | we will only be here when execution is stopped at the beginning | |
1044 | of the program. Relocation is necessary if the address at which | |
1045 | we are presently stopped differs from the start address stored in | |
1046 | the executable AND there's no interpreter section. The condition | |
1047 | regarding the interpreter section is very important because if | |
1048 | there *is* an interpreter section, execution will begin there | |
1049 | instead. When there is an interpreter section, the start address | |
1050 | is (presumably) used by the interpreter at some point to start | |
1051 | execution of the program. | |
1052 | ||
1053 | If there is an interpreter, it is normal for it to be set to an | |
1054 | arbitrary address at the outset. The job of finding it is | |
1055 | handled in enable_break(). | |
1056 | ||
1057 | So, to summarize, relocations are necessary when there is no | |
1058 | interpreter section and the start address obtained from the | |
1059 | executable is different from the address at which GDB is | |
1060 | currently stopped. | |
1061 | ||
1062 | [ The astute reader will note that we also test to make sure that | |
1063 | the executable in question has the DYNAMIC flag set. It is my | |
1064 | opinion that this test is unnecessary (undesirable even). It | |
1065 | was added to avoid inadvertent relocation of an executable | |
1066 | whose e_type member in the ELF header is not ET_DYN. There may | |
1067 | be a time in the future when it is desirable to do relocations | |
1068 | on other types of files as well in which case this condition | |
1069 | should either be removed or modified to accomodate the new file | |
1070 | type. (E.g, an ET_EXEC executable which has been built to be | |
1071 | position-independent could safely be relocated by the OS if | |
1072 | desired. It is true that this violates the ABI, but the ABI | |
1073 | has been known to be bent from time to time.) - Kevin, Nov 2000. ] | |
1074 | */ | |
1075 | ||
1076 | interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); | |
1077 | if (interp_sect == NULL | |
1078 | && (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0 | |
1079 | && bfd_get_start_address (exec_bfd) != pc) | |
1080 | { | |
1081 | struct cleanup *old_chain; | |
1082 | struct section_offsets *new_offsets; | |
1083 | int i, changed; | |
1084 | CORE_ADDR displacement; | |
1085 | ||
1086 | /* It is necessary to relocate the objfile. The amount to | |
1087 | relocate by is simply the address at which we are stopped | |
1088 | minus the starting address from the executable. | |
1089 | ||
1090 | We relocate all of the sections by the same amount. This | |
1091 | behavior is mandated by recent editions of the System V ABI. | |
1092 | According to the System V Application Binary Interface, | |
1093 | Edition 4.1, page 5-5: | |
1094 | ||
1095 | ... Though the system chooses virtual addresses for | |
1096 | individual processes, it maintains the segments' relative | |
1097 | positions. Because position-independent code uses relative | |
1098 | addressesing between segments, the difference between | |
1099 | virtual addresses in memory must match the difference | |
1100 | between virtual addresses in the file. The difference | |
1101 | between the virtual address of any segment in memory and | |
1102 | the corresponding virtual address in the file is thus a | |
1103 | single constant value for any one executable or shared | |
1104 | object in a given process. This difference is the base | |
1105 | address. One use of the base address is to relocate the | |
1106 | memory image of the program during dynamic linking. | |
1107 | ||
1108 | The same language also appears in Edition 4.0 of the System V | |
1109 | ABI and is left unspecified in some of the earlier editions. */ | |
1110 | ||
1111 | displacement = pc - bfd_get_start_address (exec_bfd); | |
1112 | changed = 0; | |
1113 | ||
13fc0c2f KB |
1114 | new_offsets = xcalloc (symfile_objfile->num_sections, |
1115 | sizeof (struct section_offsets)); | |
b8c9b27d | 1116 | old_chain = make_cleanup (xfree, new_offsets); |
e2a44558 KB |
1117 | |
1118 | for (i = 0; i < symfile_objfile->num_sections; i++) | |
1119 | { | |
1120 | if (displacement != ANOFFSET (symfile_objfile->section_offsets, i)) | |
1121 | changed = 1; | |
1122 | new_offsets->offsets[i] = displacement; | |
1123 | } | |
1124 | ||
1125 | if (changed) | |
1126 | objfile_relocate (symfile_objfile, new_offsets); | |
1127 | ||
1128 | do_cleanups (old_chain); | |
1129 | } | |
1130 | } | |
1131 | ||
13437d4b KB |
1132 | /* |
1133 | ||
1134 | GLOBAL FUNCTION | |
1135 | ||
1136 | svr4_solib_create_inferior_hook -- shared library startup support | |
1137 | ||
1138 | SYNOPSIS | |
1139 | ||
1140 | void svr4_solib_create_inferior_hook() | |
1141 | ||
1142 | DESCRIPTION | |
1143 | ||
1144 | When gdb starts up the inferior, it nurses it along (through the | |
1145 | shell) until it is ready to execute it's first instruction. At this | |
1146 | point, this function gets called via expansion of the macro | |
1147 | SOLIB_CREATE_INFERIOR_HOOK. | |
1148 | ||
1149 | For SunOS executables, this first instruction is typically the | |
1150 | one at "_start", or a similar text label, regardless of whether | |
1151 | the executable is statically or dynamically linked. The runtime | |
1152 | startup code takes care of dynamically linking in any shared | |
1153 | libraries, once gdb allows the inferior to continue. | |
1154 | ||
1155 | For SVR4 executables, this first instruction is either the first | |
1156 | instruction in the dynamic linker (for dynamically linked | |
1157 | executables) or the instruction at "start" for statically linked | |
1158 | executables. For dynamically linked executables, the system | |
1159 | first exec's /lib/libc.so.N, which contains the dynamic linker, | |
1160 | and starts it running. The dynamic linker maps in any needed | |
1161 | shared libraries, maps in the actual user executable, and then | |
1162 | jumps to "start" in the user executable. | |
1163 | ||
1164 | For both SunOS shared libraries, and SVR4 shared libraries, we | |
1165 | can arrange to cooperate with the dynamic linker to discover the | |
1166 | names of shared libraries that are dynamically linked, and the | |
1167 | base addresses to which they are linked. | |
1168 | ||
1169 | This function is responsible for discovering those names and | |
1170 | addresses, and saving sufficient information about them to allow | |
1171 | their symbols to be read at a later time. | |
1172 | ||
1173 | FIXME | |
1174 | ||
1175 | Between enable_break() and disable_break(), this code does not | |
1176 | properly handle hitting breakpoints which the user might have | |
1177 | set in the startup code or in the dynamic linker itself. Proper | |
1178 | handling will probably have to wait until the implementation is | |
1179 | changed to use the "breakpoint handler function" method. | |
1180 | ||
1181 | Also, what if child has exit()ed? Must exit loop somehow. | |
1182 | */ | |
1183 | ||
e2a44558 | 1184 | static void |
13437d4b KB |
1185 | svr4_solib_create_inferior_hook (void) |
1186 | { | |
e2a44558 KB |
1187 | /* Relocate the main executable if necessary. */ |
1188 | svr4_relocate_main_executable (); | |
1189 | ||
13437d4b KB |
1190 | if (!enable_break ()) |
1191 | { | |
1192 | warning ("shared library handler failed to enable breakpoint"); | |
1193 | return; | |
1194 | } | |
1195 | ||
ab31aa69 KB |
1196 | #if defined(_SCO_DS) |
1197 | /* SCO needs the loop below, other systems should be using the | |
13437d4b KB |
1198 | special shared library breakpoints and the shared library breakpoint |
1199 | service routine. | |
1200 | ||
1201 | Now run the target. It will eventually hit the breakpoint, at | |
1202 | which point all of the libraries will have been mapped in and we | |
1203 | can go groveling around in the dynamic linker structures to find | |
1204 | out what we need to know about them. */ | |
1205 | ||
1206 | clear_proceed_status (); | |
1207 | stop_soon_quietly = 1; | |
1208 | stop_signal = TARGET_SIGNAL_0; | |
1209 | do | |
1210 | { | |
39f77062 | 1211 | target_resume (pid_to_ptid (-1), 0, stop_signal); |
13437d4b KB |
1212 | wait_for_inferior (); |
1213 | } | |
1214 | while (stop_signal != TARGET_SIGNAL_TRAP); | |
1215 | stop_soon_quietly = 0; | |
ab31aa69 | 1216 | #endif /* defined(_SCO_DS) */ |
13437d4b KB |
1217 | } |
1218 | ||
1219 | static void | |
1220 | svr4_clear_solib (void) | |
1221 | { | |
1222 | debug_base = 0; | |
1223 | } | |
1224 | ||
1225 | static void | |
1226 | svr4_free_so (struct so_list *so) | |
1227 | { | |
b8c9b27d KB |
1228 | xfree (so->lm_info->lm); |
1229 | xfree (so->lm_info); | |
13437d4b KB |
1230 | } |
1231 | ||
6bb7be43 JB |
1232 | |
1233 | /* Clear any bits of ADDR that wouldn't fit in a target-format | |
1234 | data pointer. "Data pointer" here refers to whatever sort of | |
1235 | address the dynamic linker uses to manage its sections. At the | |
1236 | moment, we don't support shared libraries on any processors where | |
1237 | code and data pointers are different sizes. | |
1238 | ||
1239 | This isn't really the right solution. What we really need here is | |
1240 | a way to do arithmetic on CORE_ADDR values that respects the | |
1241 | natural pointer/address correspondence. (For example, on the MIPS, | |
1242 | converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to | |
1243 | sign-extend the value. There, simply truncating the bits above | |
1244 | TARGET_PTR_BIT, as we do below, is no good.) This should probably | |
1245 | be a new gdbarch method or something. */ | |
1246 | static CORE_ADDR | |
1247 | svr4_truncate_ptr (CORE_ADDR addr) | |
1248 | { | |
1249 | if (TARGET_PTR_BIT == sizeof (CORE_ADDR) * 8) | |
1250 | /* We don't need to truncate anything, and the bit twiddling below | |
1251 | will fail due to overflow problems. */ | |
1252 | return addr; | |
1253 | else | |
1254 | return addr & (((CORE_ADDR) 1 << TARGET_PTR_BIT) - 1); | |
1255 | } | |
1256 | ||
1257 | ||
749499cb KB |
1258 | static void |
1259 | svr4_relocate_section_addresses (struct so_list *so, | |
1260 | struct section_table *sec) | |
1261 | { | |
6bb7be43 JB |
1262 | sec->addr = svr4_truncate_ptr (sec->addr + LM_ADDR (so)); |
1263 | sec->endaddr = svr4_truncate_ptr (sec->endaddr + LM_ADDR (so)); | |
749499cb KB |
1264 | } |
1265 | ||
6bb7be43 | 1266 | |
e5e2b9ff KB |
1267 | /* Fetch a link_map_offsets structure for native targets using struct |
1268 | definitions from link.h. See solib-legacy.c for the function | |
1269 | which does the actual work. | |
1270 | ||
1271 | Note: For non-native targets (i.e. cross-debugging situations), | |
1272 | a target specific fetch_link_map_offsets() function should be | |
1273 | defined and registered via set_solib_svr4_fetch_link_map_offsets(). */ | |
1274 | ||
1275 | static struct link_map_offsets * | |
1276 | legacy_fetch_link_map_offsets (void) | |
1277 | { | |
1278 | if (legacy_svr4_fetch_link_map_offsets_hook) | |
1279 | return legacy_svr4_fetch_link_map_offsets_hook (); | |
1280 | else | |
1281 | { | |
1282 | internal_error (__FILE__, __LINE__, | |
1283 | "legacy_fetch_link_map_offsets called without legacy " | |
1284 | "link_map support enabled."); | |
1285 | return 0; | |
1286 | } | |
1287 | } | |
1288 | ||
1289 | /* Fetch a link_map_offsets structure using the method registered in the | |
1290 | architecture vector. */ | |
1291 | ||
1292 | static struct link_map_offsets * | |
1293 | svr4_fetch_link_map_offsets (void) | |
1294 | { | |
1295 | struct link_map_offsets *(*flmo)(void) = | |
451fbdda | 1296 | gdbarch_data (current_gdbarch, fetch_link_map_offsets_gdbarch_data); |
e5e2b9ff KB |
1297 | |
1298 | if (flmo == NULL) | |
1299 | { | |
1300 | internal_error (__FILE__, __LINE__, | |
1301 | "svr4_fetch_link_map_offsets: fetch_link_map_offsets " | |
1302 | "method not defined for this architecture."); | |
1303 | return 0; | |
1304 | } | |
1305 | else | |
1306 | return (flmo ()); | |
1307 | } | |
1308 | ||
1c4dcb57 | 1309 | /* set_solib_svr4_fetch_link_map_offsets() is intended to be called by |
e5e2b9ff KB |
1310 | a <arch>_gdbarch_init() function. It is used to establish an |
1311 | architecture specific link_map_offsets fetcher for the architecture | |
1312 | being defined. */ | |
1c4dcb57 | 1313 | |
21479ded | 1314 | void |
e5e2b9ff KB |
1315 | set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch, |
1316 | struct link_map_offsets *(*flmo) (void)) | |
21479ded | 1317 | { |
e5e2b9ff | 1318 | set_gdbarch_data (gdbarch, fetch_link_map_offsets_gdbarch_data, flmo); |
21479ded KB |
1319 | } |
1320 | ||
6ac5df3a MK |
1321 | /* Initialize the architecture-specific link_map_offsets fetcher. |
1322 | This is called after <arch>_gdbarch_init() has set up its `struct | |
1323 | gdbarch' for the new architecture, and is only called if the | |
1324 | link_map_offsets fetcher isn't already initialized (which is | |
1325 | usually done by calling set_solib_svr4_fetch_link_map_offsets() | |
1326 | above in <arch>_gdbarch_init()). Therefore we attempt to provide a | |
1327 | reasonable alternative (for native targets anyway) if the | |
1328 | <arch>_gdbarch_init() fails to call | |
e5e2b9ff | 1329 | set_solib_svr4_fetch_link_map_offsets(). */ |
1c4dcb57 | 1330 | |
e5e2b9ff KB |
1331 | static void * |
1332 | init_fetch_link_map_offsets (struct gdbarch *gdbarch) | |
21479ded | 1333 | { |
6ac5df3a | 1334 | return legacy_fetch_link_map_offsets; |
21479ded KB |
1335 | } |
1336 | ||
13437d4b KB |
1337 | static struct target_so_ops svr4_so_ops; |
1338 | ||
1339 | void | |
1340 | _initialize_svr4_solib (void) | |
1341 | { | |
e5e2b9ff KB |
1342 | fetch_link_map_offsets_gdbarch_data = |
1343 | register_gdbarch_data (init_fetch_link_map_offsets, 0); | |
21479ded | 1344 | |
749499cb | 1345 | svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses; |
13437d4b KB |
1346 | svr4_so_ops.free_so = svr4_free_so; |
1347 | svr4_so_ops.clear_solib = svr4_clear_solib; | |
1348 | svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook; | |
1349 | svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling; | |
1350 | svr4_so_ops.current_sos = svr4_current_sos; | |
1351 | svr4_so_ops.open_symbol_file_object = open_symbol_file_object; | |
d7fa2ae2 | 1352 | svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code; |
13437d4b KB |
1353 | |
1354 | /* FIXME: Don't do this here. *_gdbarch_init() should set so_ops. */ | |
1355 | current_target_so_ops = &svr4_so_ops; | |
1356 | } |