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ab31aa69 | 1 | /* Handle SVR4 shared libraries for GDB, the GNU Debugger. |
2f4950cd | 2 | |
6aba47ca | 3 | Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, |
0fb0cc75 JB |
4 | 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009 |
5 | Free Software Foundation, Inc. | |
13437d4b KB |
6 | |
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 11 | the Free Software Foundation; either version 3 of the License, or |
13437d4b KB |
12 | (at your option) any later version. |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
13437d4b | 21 | |
13437d4b KB |
22 | #include "defs.h" |
23 | ||
13437d4b | 24 | #include "elf/external.h" |
21479ded | 25 | #include "elf/common.h" |
f7856c8f | 26 | #include "elf/mips.h" |
13437d4b KB |
27 | |
28 | #include "symtab.h" | |
29 | #include "bfd.h" | |
30 | #include "symfile.h" | |
31 | #include "objfiles.h" | |
32 | #include "gdbcore.h" | |
13437d4b | 33 | #include "target.h" |
13437d4b | 34 | #include "inferior.h" |
2020b7ab | 35 | #include "gdbthread.h" |
13437d4b | 36 | |
4b188b9f MK |
37 | #include "gdb_assert.h" |
38 | ||
13437d4b | 39 | #include "solist.h" |
bba93f6c | 40 | #include "solib.h" |
13437d4b KB |
41 | #include "solib-svr4.h" |
42 | ||
2f4950cd | 43 | #include "bfd-target.h" |
cc10cae3 | 44 | #include "elf-bfd.h" |
2f4950cd | 45 | #include "exec.h" |
8d4e36ba | 46 | #include "auxv.h" |
f1838a98 | 47 | #include "exceptions.h" |
2f4950cd | 48 | |
e5e2b9ff | 49 | static struct link_map_offsets *svr4_fetch_link_map_offsets (void); |
d5a921c9 | 50 | static int svr4_have_link_map_offsets (void); |
1c4dcb57 | 51 | |
13437d4b KB |
52 | /* Link map info to include in an allocated so_list entry */ |
53 | ||
54 | struct lm_info | |
55 | { | |
56 | /* Pointer to copy of link map from inferior. The type is char * | |
57 | rather than void *, so that we may use byte offsets to find the | |
58 | various fields without the need for a cast. */ | |
4066fc10 | 59 | gdb_byte *lm; |
cc10cae3 AO |
60 | |
61 | /* Amount by which addresses in the binary should be relocated to | |
62 | match the inferior. This could most often be taken directly | |
63 | from lm, but when prelinking is involved and the prelink base | |
64 | address changes, we may need a different offset, we want to | |
65 | warn about the difference and compute it only once. */ | |
66 | CORE_ADDR l_addr; | |
93a57060 DJ |
67 | |
68 | /* The target location of lm. */ | |
69 | CORE_ADDR lm_addr; | |
13437d4b KB |
70 | }; |
71 | ||
72 | /* On SVR4 systems, a list of symbols in the dynamic linker where | |
73 | GDB can try to place a breakpoint to monitor shared library | |
74 | events. | |
75 | ||
76 | If none of these symbols are found, or other errors occur, then | |
77 | SVR4 systems will fall back to using a symbol as the "startup | |
78 | mapping complete" breakpoint address. */ | |
79 | ||
13437d4b KB |
80 | static char *solib_break_names[] = |
81 | { | |
82 | "r_debug_state", | |
83 | "_r_debug_state", | |
84 | "_dl_debug_state", | |
85 | "rtld_db_dlactivity", | |
1f72e589 | 86 | "_rtld_debug_state", |
4c0122c8 | 87 | |
13437d4b KB |
88 | NULL |
89 | }; | |
13437d4b | 90 | |
13437d4b KB |
91 | static char *bkpt_names[] = |
92 | { | |
13437d4b | 93 | "_start", |
ad3dcc5c | 94 | "__start", |
13437d4b KB |
95 | "main", |
96 | NULL | |
97 | }; | |
13437d4b | 98 | |
13437d4b KB |
99 | static char *main_name_list[] = |
100 | { | |
101 | "main_$main", | |
102 | NULL | |
103 | }; | |
104 | ||
4d7b2d5b JB |
105 | /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent |
106 | the same shared library. */ | |
107 | ||
108 | static int | |
109 | svr4_same_1 (const char *gdb_so_name, const char *inferior_so_name) | |
110 | { | |
111 | if (strcmp (gdb_so_name, inferior_so_name) == 0) | |
112 | return 1; | |
113 | ||
114 | /* On Solaris, when starting inferior we think that dynamic linker is | |
115 | /usr/lib/ld.so.1, but later on, the table of loaded shared libraries | |
116 | contains /lib/ld.so.1. Sometimes one file is a link to another, but | |
117 | sometimes they have identical content, but are not linked to each | |
118 | other. We don't restrict this check for Solaris, but the chances | |
119 | of running into this situation elsewhere are very low. */ | |
120 | if (strcmp (gdb_so_name, "/usr/lib/ld.so.1") == 0 | |
121 | && strcmp (inferior_so_name, "/lib/ld.so.1") == 0) | |
122 | return 1; | |
123 | ||
124 | /* Similarly, we observed the same issue with sparc64, but with | |
125 | different locations. */ | |
126 | if (strcmp (gdb_so_name, "/usr/lib/sparcv9/ld.so.1") == 0 | |
127 | && strcmp (inferior_so_name, "/lib/sparcv9/ld.so.1") == 0) | |
128 | return 1; | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
133 | static int | |
134 | svr4_same (struct so_list *gdb, struct so_list *inferior) | |
135 | { | |
136 | return (svr4_same_1 (gdb->so_original_name, inferior->so_original_name)); | |
137 | } | |
138 | ||
13437d4b KB |
139 | /* link map access functions */ |
140 | ||
141 | static CORE_ADDR | |
cc10cae3 | 142 | LM_ADDR_FROM_LINK_MAP (struct so_list *so) |
13437d4b | 143 | { |
4b188b9f | 144 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
b6da22b0 | 145 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
13437d4b | 146 | |
cfaefc65 | 147 | return extract_typed_address (so->lm_info->lm + lmo->l_addr_offset, |
b6da22b0 | 148 | ptr_type); |
13437d4b KB |
149 | } |
150 | ||
cc10cae3 | 151 | static int |
2c0b251b | 152 | HAS_LM_DYNAMIC_FROM_LINK_MAP (void) |
cc10cae3 AO |
153 | { |
154 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); | |
155 | ||
cfaefc65 | 156 | return lmo->l_ld_offset >= 0; |
cc10cae3 AO |
157 | } |
158 | ||
159 | static CORE_ADDR | |
160 | LM_DYNAMIC_FROM_LINK_MAP (struct so_list *so) | |
161 | { | |
162 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); | |
b6da22b0 | 163 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
cc10cae3 | 164 | |
cfaefc65 | 165 | return extract_typed_address (so->lm_info->lm + lmo->l_ld_offset, |
b6da22b0 | 166 | ptr_type); |
cc10cae3 AO |
167 | } |
168 | ||
169 | static CORE_ADDR | |
170 | LM_ADDR_CHECK (struct so_list *so, bfd *abfd) | |
171 | { | |
172 | if (so->lm_info->l_addr == (CORE_ADDR)-1) | |
173 | { | |
174 | struct bfd_section *dyninfo_sect; | |
175 | CORE_ADDR l_addr, l_dynaddr, dynaddr, align = 0x1000; | |
176 | ||
177 | l_addr = LM_ADDR_FROM_LINK_MAP (so); | |
178 | ||
179 | if (! abfd || ! HAS_LM_DYNAMIC_FROM_LINK_MAP ()) | |
180 | goto set_addr; | |
181 | ||
182 | l_dynaddr = LM_DYNAMIC_FROM_LINK_MAP (so); | |
183 | ||
184 | dyninfo_sect = bfd_get_section_by_name (abfd, ".dynamic"); | |
185 | if (dyninfo_sect == NULL) | |
186 | goto set_addr; | |
187 | ||
188 | dynaddr = bfd_section_vma (abfd, dyninfo_sect); | |
189 | ||
190 | if (dynaddr + l_addr != l_dynaddr) | |
191 | { | |
cc10cae3 AO |
192 | if (bfd_get_flavour (abfd) == bfd_target_elf_flavour) |
193 | { | |
194 | Elf_Internal_Ehdr *ehdr = elf_tdata (abfd)->elf_header; | |
195 | Elf_Internal_Phdr *phdr = elf_tdata (abfd)->phdr; | |
196 | int i; | |
197 | ||
198 | align = 1; | |
199 | ||
200 | for (i = 0; i < ehdr->e_phnum; i++) | |
201 | if (phdr[i].p_type == PT_LOAD && phdr[i].p_align > align) | |
202 | align = phdr[i].p_align; | |
203 | } | |
204 | ||
205 | /* Turn it into a mask. */ | |
206 | align--; | |
207 | ||
208 | /* If the changes match the alignment requirements, we | |
209 | assume we're using a core file that was generated by the | |
210 | same binary, just prelinked with a different base offset. | |
211 | If it doesn't match, we may have a different binary, the | |
212 | same binary with the dynamic table loaded at an unrelated | |
213 | location, or anything, really. To avoid regressions, | |
214 | don't adjust the base offset in the latter case, although | |
215 | odds are that, if things really changed, debugging won't | |
216 | quite work. */ | |
f1e55806 | 217 | if ((l_addr & align) == ((l_dynaddr - dynaddr) & align)) |
cc10cae3 AO |
218 | { |
219 | l_addr = l_dynaddr - dynaddr; | |
79d4c408 DJ |
220 | |
221 | warning (_(".dynamic section for \"%s\" " | |
222 | "is not at the expected address"), so->so_name); | |
cc10cae3 AO |
223 | warning (_("difference appears to be caused by prelink, " |
224 | "adjusting expectations")); | |
225 | } | |
79d4c408 DJ |
226 | else |
227 | warning (_(".dynamic section for \"%s\" " | |
228 | "is not at the expected address " | |
229 | "(wrong library or version mismatch?)"), so->so_name); | |
cc10cae3 AO |
230 | } |
231 | ||
232 | set_addr: | |
233 | so->lm_info->l_addr = l_addr; | |
234 | } | |
235 | ||
236 | return so->lm_info->l_addr; | |
237 | } | |
238 | ||
13437d4b KB |
239 | static CORE_ADDR |
240 | LM_NEXT (struct so_list *so) | |
241 | { | |
4b188b9f | 242 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
b6da22b0 | 243 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
13437d4b | 244 | |
cfaefc65 | 245 | return extract_typed_address (so->lm_info->lm + lmo->l_next_offset, |
b6da22b0 | 246 | ptr_type); |
13437d4b KB |
247 | } |
248 | ||
249 | static CORE_ADDR | |
250 | LM_NAME (struct so_list *so) | |
251 | { | |
4b188b9f | 252 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
b6da22b0 | 253 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
13437d4b | 254 | |
cfaefc65 | 255 | return extract_typed_address (so->lm_info->lm + lmo->l_name_offset, |
b6da22b0 | 256 | ptr_type); |
13437d4b KB |
257 | } |
258 | ||
13437d4b KB |
259 | static int |
260 | IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list *so) | |
261 | { | |
4b188b9f | 262 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
b6da22b0 | 263 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
13437d4b | 264 | |
e499d0f1 DJ |
265 | /* Assume that everything is a library if the dynamic loader was loaded |
266 | late by a static executable. */ | |
267 | if (bfd_get_section_by_name (exec_bfd, ".dynamic") == NULL) | |
268 | return 0; | |
269 | ||
cfaefc65 | 270 | return extract_typed_address (so->lm_info->lm + lmo->l_prev_offset, |
b6da22b0 | 271 | ptr_type) == 0; |
13437d4b KB |
272 | } |
273 | ||
13437d4b | 274 | static CORE_ADDR debug_base; /* Base of dynamic linker structures */ |
13437d4b | 275 | |
34439770 DJ |
276 | /* Validity flag for debug_loader_offset. */ |
277 | static int debug_loader_offset_p; | |
278 | ||
279 | /* Load address for the dynamic linker, inferred. */ | |
280 | static CORE_ADDR debug_loader_offset; | |
281 | ||
282 | /* Name of the dynamic linker, valid if debug_loader_offset_p. */ | |
283 | static char *debug_loader_name; | |
284 | ||
93a57060 DJ |
285 | /* Load map address for the main executable. */ |
286 | static CORE_ADDR main_lm_addr; | |
287 | ||
13437d4b KB |
288 | /* Local function prototypes */ |
289 | ||
290 | static int match_main (char *); | |
291 | ||
2bbe3cc1 | 292 | static CORE_ADDR bfd_lookup_symbol (bfd *, char *); |
13437d4b KB |
293 | |
294 | /* | |
295 | ||
296 | LOCAL FUNCTION | |
297 | ||
298 | bfd_lookup_symbol -- lookup the value for a specific symbol | |
299 | ||
300 | SYNOPSIS | |
301 | ||
2bbe3cc1 | 302 | CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname) |
13437d4b KB |
303 | |
304 | DESCRIPTION | |
305 | ||
306 | An expensive way to lookup the value of a single symbol for | |
307 | bfd's that are only temporary anyway. This is used by the | |
308 | shared library support to find the address of the debugger | |
2bbe3cc1 | 309 | notification routine in the shared library. |
13437d4b | 310 | |
2bbe3cc1 DJ |
311 | The returned symbol may be in a code or data section; functions |
312 | will normally be in a code section, but may be in a data section | |
313 | if this architecture uses function descriptors. | |
87f84c9d | 314 | |
13437d4b KB |
315 | Note that 0 is specifically allowed as an error return (no |
316 | such symbol). | |
317 | */ | |
318 | ||
319 | static CORE_ADDR | |
2bbe3cc1 | 320 | bfd_lookup_symbol (bfd *abfd, char *symname) |
13437d4b | 321 | { |
435b259c | 322 | long storage_needed; |
13437d4b KB |
323 | asymbol *sym; |
324 | asymbol **symbol_table; | |
325 | unsigned int number_of_symbols; | |
326 | unsigned int i; | |
327 | struct cleanup *back_to; | |
328 | CORE_ADDR symaddr = 0; | |
329 | ||
330 | storage_needed = bfd_get_symtab_upper_bound (abfd); | |
331 | ||
332 | if (storage_needed > 0) | |
333 | { | |
334 | symbol_table = (asymbol **) xmalloc (storage_needed); | |
4efb68b1 | 335 | back_to = make_cleanup (xfree, symbol_table); |
13437d4b KB |
336 | number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); |
337 | ||
338 | for (i = 0; i < number_of_symbols; i++) | |
339 | { | |
340 | sym = *symbol_table++; | |
6314a349 | 341 | if (strcmp (sym->name, symname) == 0 |
2bbe3cc1 | 342 | && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0) |
13437d4b | 343 | { |
2bbe3cc1 | 344 | /* BFD symbols are section relative. */ |
13437d4b KB |
345 | symaddr = sym->value + sym->section->vma; |
346 | break; | |
347 | } | |
348 | } | |
349 | do_cleanups (back_to); | |
350 | } | |
351 | ||
352 | if (symaddr) | |
353 | return symaddr; | |
354 | ||
355 | /* On FreeBSD, the dynamic linker is stripped by default. So we'll | |
356 | have to check the dynamic string table too. */ | |
357 | ||
358 | storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd); | |
359 | ||
360 | if (storage_needed > 0) | |
361 | { | |
362 | symbol_table = (asymbol **) xmalloc (storage_needed); | |
4efb68b1 | 363 | back_to = make_cleanup (xfree, symbol_table); |
13437d4b KB |
364 | number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table); |
365 | ||
366 | for (i = 0; i < number_of_symbols; i++) | |
367 | { | |
368 | sym = *symbol_table++; | |
87f84c9d | 369 | |
6314a349 | 370 | if (strcmp (sym->name, symname) == 0 |
2bbe3cc1 | 371 | && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0) |
13437d4b | 372 | { |
2bbe3cc1 | 373 | /* BFD symbols are section relative. */ |
13437d4b KB |
374 | symaddr = sym->value + sym->section->vma; |
375 | break; | |
376 | } | |
377 | } | |
378 | do_cleanups (back_to); | |
379 | } | |
380 | ||
381 | return symaddr; | |
382 | } | |
383 | ||
97ec2c2f UW |
384 | |
385 | /* Read program header TYPE from inferior memory. The header is found | |
386 | by scanning the OS auxillary vector. | |
387 | ||
388 | Return a pointer to allocated memory holding the program header contents, | |
389 | or NULL on failure. If sucessful, and unless P_SECT_SIZE is NULL, the | |
390 | size of those contents is returned to P_SECT_SIZE. Likewise, the target | |
391 | architecture size (32-bit or 64-bit) is returned to P_ARCH_SIZE. */ | |
392 | ||
393 | static gdb_byte * | |
394 | read_program_header (int type, int *p_sect_size, int *p_arch_size) | |
395 | { | |
396 | CORE_ADDR at_phdr, at_phent, at_phnum; | |
397 | int arch_size, sect_size; | |
398 | CORE_ADDR sect_addr; | |
399 | gdb_byte *buf; | |
400 | ||
401 | /* Get required auxv elements from target. */ | |
402 | if (target_auxv_search (¤t_target, AT_PHDR, &at_phdr) <= 0) | |
403 | return 0; | |
404 | if (target_auxv_search (¤t_target, AT_PHENT, &at_phent) <= 0) | |
405 | return 0; | |
406 | if (target_auxv_search (¤t_target, AT_PHNUM, &at_phnum) <= 0) | |
407 | return 0; | |
408 | if (!at_phdr || !at_phnum) | |
409 | return 0; | |
410 | ||
411 | /* Determine ELF architecture type. */ | |
412 | if (at_phent == sizeof (Elf32_External_Phdr)) | |
413 | arch_size = 32; | |
414 | else if (at_phent == sizeof (Elf64_External_Phdr)) | |
415 | arch_size = 64; | |
416 | else | |
417 | return 0; | |
418 | ||
419 | /* Find .dynamic section via the PT_DYNAMIC PHDR. */ | |
420 | if (arch_size == 32) | |
421 | { | |
422 | Elf32_External_Phdr phdr; | |
423 | int i; | |
424 | ||
425 | /* Search for requested PHDR. */ | |
426 | for (i = 0; i < at_phnum; i++) | |
427 | { | |
428 | if (target_read_memory (at_phdr + i * sizeof (phdr), | |
429 | (gdb_byte *)&phdr, sizeof (phdr))) | |
430 | return 0; | |
431 | ||
432 | if (extract_unsigned_integer ((gdb_byte *)phdr.p_type, 4) == type) | |
433 | break; | |
434 | } | |
435 | ||
436 | if (i == at_phnum) | |
437 | return 0; | |
438 | ||
439 | /* Retrieve address and size. */ | |
440 | sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr, 4); | |
441 | sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz, 4); | |
442 | } | |
443 | else | |
444 | { | |
445 | Elf64_External_Phdr phdr; | |
446 | int i; | |
447 | ||
448 | /* Search for requested PHDR. */ | |
449 | for (i = 0; i < at_phnum; i++) | |
450 | { | |
451 | if (target_read_memory (at_phdr + i * sizeof (phdr), | |
452 | (gdb_byte *)&phdr, sizeof (phdr))) | |
453 | return 0; | |
454 | ||
455 | if (extract_unsigned_integer ((gdb_byte *)phdr.p_type, 4) == type) | |
456 | break; | |
457 | } | |
458 | ||
459 | if (i == at_phnum) | |
460 | return 0; | |
461 | ||
462 | /* Retrieve address and size. */ | |
463 | sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr, 8); | |
464 | sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz, 8); | |
465 | } | |
466 | ||
467 | /* Read in requested program header. */ | |
468 | buf = xmalloc (sect_size); | |
469 | if (target_read_memory (sect_addr, buf, sect_size)) | |
470 | { | |
471 | xfree (buf); | |
472 | return NULL; | |
473 | } | |
474 | ||
475 | if (p_arch_size) | |
476 | *p_arch_size = arch_size; | |
477 | if (p_sect_size) | |
478 | *p_sect_size = sect_size; | |
479 | ||
480 | return buf; | |
481 | } | |
482 | ||
483 | ||
484 | /* Return program interpreter string. */ | |
485 | static gdb_byte * | |
486 | find_program_interpreter (void) | |
487 | { | |
488 | gdb_byte *buf = NULL; | |
489 | ||
490 | /* If we have an exec_bfd, use its section table. */ | |
491 | if (exec_bfd | |
492 | && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) | |
493 | { | |
494 | struct bfd_section *interp_sect; | |
495 | ||
496 | interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); | |
497 | if (interp_sect != NULL) | |
498 | { | |
499 | CORE_ADDR sect_addr = bfd_section_vma (exec_bfd, interp_sect); | |
500 | int sect_size = bfd_section_size (exec_bfd, interp_sect); | |
501 | ||
502 | buf = xmalloc (sect_size); | |
503 | bfd_get_section_contents (exec_bfd, interp_sect, buf, 0, sect_size); | |
504 | } | |
505 | } | |
506 | ||
507 | /* If we didn't find it, use the target auxillary vector. */ | |
508 | if (!buf) | |
509 | buf = read_program_header (PT_INTERP, NULL, NULL); | |
510 | ||
511 | return buf; | |
512 | } | |
513 | ||
514 | ||
3a40aaa0 UW |
515 | /* Scan for DYNTAG in .dynamic section of ABFD. If DYNTAG is found 1 is |
516 | returned and the corresponding PTR is set. */ | |
517 | ||
518 | static int | |
519 | scan_dyntag (int dyntag, bfd *abfd, CORE_ADDR *ptr) | |
520 | { | |
521 | int arch_size, step, sect_size; | |
522 | long dyn_tag; | |
523 | CORE_ADDR dyn_ptr, dyn_addr; | |
65728c26 | 524 | gdb_byte *bufend, *bufstart, *buf; |
3a40aaa0 UW |
525 | Elf32_External_Dyn *x_dynp_32; |
526 | Elf64_External_Dyn *x_dynp_64; | |
527 | struct bfd_section *sect; | |
528 | ||
529 | if (abfd == NULL) | |
530 | return 0; | |
531 | arch_size = bfd_get_arch_size (abfd); | |
532 | if (arch_size == -1) | |
533 | return 0; | |
534 | ||
535 | /* Find the start address of the .dynamic section. */ | |
536 | sect = bfd_get_section_by_name (abfd, ".dynamic"); | |
537 | if (sect == NULL) | |
538 | return 0; | |
539 | dyn_addr = bfd_section_vma (abfd, sect); | |
540 | ||
65728c26 DJ |
541 | /* Read in .dynamic from the BFD. We will get the actual value |
542 | from memory later. */ | |
3a40aaa0 | 543 | sect_size = bfd_section_size (abfd, sect); |
65728c26 DJ |
544 | buf = bufstart = alloca (sect_size); |
545 | if (!bfd_get_section_contents (abfd, sect, | |
546 | buf, 0, sect_size)) | |
547 | return 0; | |
3a40aaa0 UW |
548 | |
549 | /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */ | |
550 | step = (arch_size == 32) ? sizeof (Elf32_External_Dyn) | |
551 | : sizeof (Elf64_External_Dyn); | |
552 | for (bufend = buf + sect_size; | |
553 | buf < bufend; | |
554 | buf += step) | |
555 | { | |
556 | if (arch_size == 32) | |
557 | { | |
558 | x_dynp_32 = (Elf32_External_Dyn *) buf; | |
559 | dyn_tag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_tag); | |
560 | dyn_ptr = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_un.d_ptr); | |
561 | } | |
65728c26 | 562 | else |
3a40aaa0 UW |
563 | { |
564 | x_dynp_64 = (Elf64_External_Dyn *) buf; | |
565 | dyn_tag = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_tag); | |
566 | dyn_ptr = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_un.d_ptr); | |
567 | } | |
568 | if (dyn_tag == DT_NULL) | |
569 | return 0; | |
570 | if (dyn_tag == dyntag) | |
571 | { | |
65728c26 DJ |
572 | /* If requested, try to read the runtime value of this .dynamic |
573 | entry. */ | |
3a40aaa0 | 574 | if (ptr) |
65728c26 | 575 | { |
b6da22b0 | 576 | struct type *ptr_type; |
65728c26 DJ |
577 | gdb_byte ptr_buf[8]; |
578 | CORE_ADDR ptr_addr; | |
579 | ||
b6da22b0 | 580 | ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
65728c26 DJ |
581 | ptr_addr = dyn_addr + (buf - bufstart) + arch_size / 8; |
582 | if (target_read_memory (ptr_addr, ptr_buf, arch_size / 8) == 0) | |
b6da22b0 | 583 | dyn_ptr = extract_typed_address (ptr_buf, ptr_type); |
65728c26 DJ |
584 | *ptr = dyn_ptr; |
585 | } | |
586 | return 1; | |
3a40aaa0 UW |
587 | } |
588 | } | |
589 | ||
590 | return 0; | |
591 | } | |
592 | ||
97ec2c2f UW |
593 | /* Scan for DYNTAG in .dynamic section of the target's main executable, |
594 | found by consulting the OS auxillary vector. If DYNTAG is found 1 is | |
595 | returned and the corresponding PTR is set. */ | |
596 | ||
597 | static int | |
598 | scan_dyntag_auxv (int dyntag, CORE_ADDR *ptr) | |
599 | { | |
600 | int sect_size, arch_size, step; | |
601 | long dyn_tag; | |
602 | CORE_ADDR dyn_ptr; | |
603 | gdb_byte *bufend, *bufstart, *buf; | |
604 | ||
605 | /* Read in .dynamic section. */ | |
606 | buf = bufstart = read_program_header (PT_DYNAMIC, §_size, &arch_size); | |
607 | if (!buf) | |
608 | return 0; | |
609 | ||
610 | /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */ | |
611 | step = (arch_size == 32) ? sizeof (Elf32_External_Dyn) | |
612 | : sizeof (Elf64_External_Dyn); | |
613 | for (bufend = buf + sect_size; | |
614 | buf < bufend; | |
615 | buf += step) | |
616 | { | |
617 | if (arch_size == 32) | |
618 | { | |
619 | Elf32_External_Dyn *dynp = (Elf32_External_Dyn *) buf; | |
620 | dyn_tag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag, 4); | |
621 | dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr, 4); | |
622 | } | |
623 | else | |
624 | { | |
625 | Elf64_External_Dyn *dynp = (Elf64_External_Dyn *) buf; | |
626 | dyn_tag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag, 8); | |
627 | dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr, 8); | |
628 | } | |
629 | if (dyn_tag == DT_NULL) | |
630 | break; | |
631 | ||
632 | if (dyn_tag == dyntag) | |
633 | { | |
634 | if (ptr) | |
635 | *ptr = dyn_ptr; | |
636 | ||
637 | xfree (bufstart); | |
638 | return 1; | |
639 | } | |
640 | } | |
641 | ||
642 | xfree (bufstart); | |
643 | return 0; | |
644 | } | |
645 | ||
3a40aaa0 | 646 | |
13437d4b KB |
647 | /* |
648 | ||
649 | LOCAL FUNCTION | |
650 | ||
651 | elf_locate_base -- locate the base address of dynamic linker structs | |
652 | for SVR4 elf targets. | |
653 | ||
654 | SYNOPSIS | |
655 | ||
656 | CORE_ADDR elf_locate_base (void) | |
657 | ||
658 | DESCRIPTION | |
659 | ||
660 | For SVR4 elf targets the address of the dynamic linker's runtime | |
661 | structure is contained within the dynamic info section in the | |
662 | executable file. The dynamic section is also mapped into the | |
663 | inferior address space. Because the runtime loader fills in the | |
664 | real address before starting the inferior, we have to read in the | |
665 | dynamic info section from the inferior address space. | |
666 | If there are any errors while trying to find the address, we | |
667 | silently return 0, otherwise the found address is returned. | |
668 | ||
669 | */ | |
670 | ||
671 | static CORE_ADDR | |
672 | elf_locate_base (void) | |
673 | { | |
3a40aaa0 UW |
674 | struct minimal_symbol *msymbol; |
675 | CORE_ADDR dyn_ptr; | |
13437d4b | 676 | |
65728c26 DJ |
677 | /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this |
678 | instead of DT_DEBUG, although they sometimes contain an unused | |
679 | DT_DEBUG. */ | |
97ec2c2f UW |
680 | if (scan_dyntag (DT_MIPS_RLD_MAP, exec_bfd, &dyn_ptr) |
681 | || scan_dyntag_auxv (DT_MIPS_RLD_MAP, &dyn_ptr)) | |
3a40aaa0 | 682 | { |
b6da22b0 | 683 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
3a40aaa0 | 684 | gdb_byte *pbuf; |
b6da22b0 | 685 | int pbuf_size = TYPE_LENGTH (ptr_type); |
3a40aaa0 UW |
686 | pbuf = alloca (pbuf_size); |
687 | /* DT_MIPS_RLD_MAP contains a pointer to the address | |
688 | of the dynamic link structure. */ | |
689 | if (target_read_memory (dyn_ptr, pbuf, pbuf_size)) | |
e499d0f1 | 690 | return 0; |
b6da22b0 | 691 | return extract_typed_address (pbuf, ptr_type); |
e499d0f1 DJ |
692 | } |
693 | ||
65728c26 | 694 | /* Find DT_DEBUG. */ |
97ec2c2f UW |
695 | if (scan_dyntag (DT_DEBUG, exec_bfd, &dyn_ptr) |
696 | || scan_dyntag_auxv (DT_DEBUG, &dyn_ptr)) | |
65728c26 DJ |
697 | return dyn_ptr; |
698 | ||
3a40aaa0 UW |
699 | /* This may be a static executable. Look for the symbol |
700 | conventionally named _r_debug, as a last resort. */ | |
701 | msymbol = lookup_minimal_symbol ("_r_debug", NULL, symfile_objfile); | |
702 | if (msymbol != NULL) | |
703 | return SYMBOL_VALUE_ADDRESS (msymbol); | |
13437d4b KB |
704 | |
705 | /* DT_DEBUG entry not found. */ | |
706 | return 0; | |
707 | } | |
708 | ||
13437d4b KB |
709 | /* |
710 | ||
711 | LOCAL FUNCTION | |
712 | ||
713 | locate_base -- locate the base address of dynamic linker structs | |
714 | ||
715 | SYNOPSIS | |
716 | ||
717 | CORE_ADDR locate_base (void) | |
718 | ||
719 | DESCRIPTION | |
720 | ||
721 | For both the SunOS and SVR4 shared library implementations, if the | |
722 | inferior executable has been linked dynamically, there is a single | |
723 | address somewhere in the inferior's data space which is the key to | |
724 | locating all of the dynamic linker's runtime structures. This | |
725 | address is the value of the debug base symbol. The job of this | |
726 | function is to find and return that address, or to return 0 if there | |
727 | is no such address (the executable is statically linked for example). | |
728 | ||
729 | For SunOS, the job is almost trivial, since the dynamic linker and | |
730 | all of it's structures are statically linked to the executable at | |
731 | link time. Thus the symbol for the address we are looking for has | |
732 | already been added to the minimal symbol table for the executable's | |
733 | objfile at the time the symbol file's symbols were read, and all we | |
734 | have to do is look it up there. Note that we explicitly do NOT want | |
735 | to find the copies in the shared library. | |
736 | ||
737 | The SVR4 version is a bit more complicated because the address | |
738 | is contained somewhere in the dynamic info section. We have to go | |
739 | to a lot more work to discover the address of the debug base symbol. | |
740 | Because of this complexity, we cache the value we find and return that | |
741 | value on subsequent invocations. Note there is no copy in the | |
742 | executable symbol tables. | |
743 | ||
744 | */ | |
745 | ||
746 | static CORE_ADDR | |
747 | locate_base (void) | |
748 | { | |
13437d4b KB |
749 | /* Check to see if we have a currently valid address, and if so, avoid |
750 | doing all this work again and just return the cached address. If | |
751 | we have no cached address, try to locate it in the dynamic info | |
d5a921c9 KB |
752 | section for ELF executables. There's no point in doing any of this |
753 | though if we don't have some link map offsets to work with. */ | |
13437d4b | 754 | |
d5a921c9 | 755 | if (debug_base == 0 && svr4_have_link_map_offsets ()) |
13437d4b KB |
756 | { |
757 | if (exec_bfd != NULL | |
758 | && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) | |
759 | debug_base = elf_locate_base (); | |
13437d4b KB |
760 | } |
761 | return (debug_base); | |
13437d4b KB |
762 | } |
763 | ||
e4cd0d6a MK |
764 | /* Find the first element in the inferior's dynamic link map, and |
765 | return its address in the inferior. | |
13437d4b | 766 | |
e4cd0d6a MK |
767 | FIXME: Perhaps we should validate the info somehow, perhaps by |
768 | checking r_version for a known version number, or r_state for | |
769 | RT_CONSISTENT. */ | |
13437d4b KB |
770 | |
771 | static CORE_ADDR | |
e4cd0d6a | 772 | solib_svr4_r_map (void) |
13437d4b | 773 | { |
4b188b9f | 774 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
b6da22b0 | 775 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
13437d4b | 776 | |
b6da22b0 | 777 | return read_memory_typed_address (debug_base + lmo->r_map_offset, ptr_type); |
e4cd0d6a | 778 | } |
13437d4b | 779 | |
7cd25cfc DJ |
780 | /* Find r_brk from the inferior's debug base. */ |
781 | ||
782 | static CORE_ADDR | |
783 | solib_svr4_r_brk (void) | |
784 | { | |
785 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); | |
b6da22b0 | 786 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
7cd25cfc | 787 | |
b6da22b0 | 788 | return read_memory_typed_address (debug_base + lmo->r_brk_offset, ptr_type); |
7cd25cfc DJ |
789 | } |
790 | ||
e4cd0d6a MK |
791 | /* Find the link map for the dynamic linker (if it is not in the |
792 | normal list of loaded shared objects). */ | |
13437d4b | 793 | |
e4cd0d6a MK |
794 | static CORE_ADDR |
795 | solib_svr4_r_ldsomap (void) | |
796 | { | |
797 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); | |
b6da22b0 | 798 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
e4cd0d6a | 799 | ULONGEST version; |
13437d4b | 800 | |
e4cd0d6a MK |
801 | /* Check version, and return zero if `struct r_debug' doesn't have |
802 | the r_ldsomap member. */ | |
803 | version = read_memory_unsigned_integer (debug_base + lmo->r_version_offset, | |
804 | lmo->r_version_size); | |
805 | if (version < 2 || lmo->r_ldsomap_offset == -1) | |
806 | return 0; | |
13437d4b | 807 | |
e4cd0d6a | 808 | return read_memory_typed_address (debug_base + lmo->r_ldsomap_offset, |
b6da22b0 | 809 | ptr_type); |
13437d4b KB |
810 | } |
811 | ||
13437d4b KB |
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; | |
4b188b9f | 841 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
b6da22b0 UW |
842 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
843 | int l_name_size = TYPE_LENGTH (ptr_type); | |
cfaefc65 | 844 | gdb_byte *l_name_buf = xmalloc (l_name_size); |
b8c9b27d | 845 | struct cleanup *cleanups = make_cleanup (xfree, l_name_buf); |
13437d4b KB |
846 | |
847 | if (symfile_objfile) | |
9e2f0ad4 | 848 | if (!query (_("Attempt to reload symbols from process? "))) |
13437d4b KB |
849 | return 0; |
850 | ||
7cd25cfc DJ |
851 | /* Always locate the debug struct, in case it has moved. */ |
852 | debug_base = 0; | |
853 | if (locate_base () == 0) | |
13437d4b KB |
854 | return 0; /* failed somehow... */ |
855 | ||
856 | /* First link map member should be the executable. */ | |
e4cd0d6a MK |
857 | lm = solib_svr4_r_map (); |
858 | if (lm == 0) | |
13437d4b KB |
859 | return 0; /* failed somehow... */ |
860 | ||
861 | /* Read address of name from target memory to GDB. */ | |
cfaefc65 | 862 | read_memory (lm + lmo->l_name_offset, l_name_buf, l_name_size); |
13437d4b | 863 | |
cfaefc65 | 864 | /* Convert the address to host format. */ |
b6da22b0 | 865 | l_name = extract_typed_address (l_name_buf, ptr_type); |
13437d4b KB |
866 | |
867 | /* Free l_name_buf. */ | |
868 | do_cleanups (cleanups); | |
869 | ||
870 | if (l_name == 0) | |
871 | return 0; /* No filename. */ | |
872 | ||
873 | /* Now fetch the filename from target memory. */ | |
874 | target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode); | |
ea5bf0a1 | 875 | make_cleanup (xfree, filename); |
13437d4b KB |
876 | |
877 | if (errcode) | |
878 | { | |
8a3fe4f8 | 879 | warning (_("failed to read exec filename from attached file: %s"), |
13437d4b KB |
880 | safe_strerror (errcode)); |
881 | return 0; | |
882 | } | |
883 | ||
13437d4b | 884 | /* Have a pathname: read the symbol file. */ |
1adeb98a | 885 | symbol_file_add_main (filename, from_tty); |
13437d4b KB |
886 | |
887 | return 1; | |
888 | } | |
13437d4b | 889 | |
34439770 DJ |
890 | /* If no shared library information is available from the dynamic |
891 | linker, build a fallback list from other sources. */ | |
892 | ||
893 | static struct so_list * | |
894 | svr4_default_sos (void) | |
895 | { | |
896 | struct so_list *head = NULL; | |
897 | struct so_list **link_ptr = &head; | |
898 | ||
899 | if (debug_loader_offset_p) | |
900 | { | |
901 | struct so_list *new = XZALLOC (struct so_list); | |
902 | ||
903 | new->lm_info = xmalloc (sizeof (struct lm_info)); | |
904 | ||
905 | /* Nothing will ever check the cached copy of the link | |
906 | map if we set l_addr. */ | |
907 | new->lm_info->l_addr = debug_loader_offset; | |
93a57060 | 908 | new->lm_info->lm_addr = 0; |
34439770 DJ |
909 | new->lm_info->lm = NULL; |
910 | ||
911 | strncpy (new->so_name, debug_loader_name, SO_NAME_MAX_PATH_SIZE - 1); | |
912 | new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; | |
913 | strcpy (new->so_original_name, new->so_name); | |
914 | ||
915 | *link_ptr = new; | |
916 | link_ptr = &new->next; | |
917 | } | |
918 | ||
919 | return head; | |
920 | } | |
921 | ||
13437d4b KB |
922 | /* LOCAL FUNCTION |
923 | ||
924 | current_sos -- build a list of currently loaded shared objects | |
925 | ||
926 | SYNOPSIS | |
927 | ||
928 | struct so_list *current_sos () | |
929 | ||
930 | DESCRIPTION | |
931 | ||
932 | Build a list of `struct so_list' objects describing the shared | |
933 | objects currently loaded in the inferior. This list does not | |
934 | include an entry for the main executable file. | |
935 | ||
936 | Note that we only gather information directly available from the | |
937 | inferior --- we don't examine any of the shared library files | |
938 | themselves. The declaration of `struct so_list' says which fields | |
939 | we provide values for. */ | |
940 | ||
941 | static struct so_list * | |
942 | svr4_current_sos (void) | |
943 | { | |
944 | CORE_ADDR lm; | |
945 | struct so_list *head = 0; | |
946 | struct so_list **link_ptr = &head; | |
e4cd0d6a | 947 | CORE_ADDR ldsomap = 0; |
13437d4b | 948 | |
7cd25cfc DJ |
949 | /* Always locate the debug struct, in case it has moved. */ |
950 | debug_base = 0; | |
951 | locate_base (); | |
13437d4b | 952 | |
7cd25cfc DJ |
953 | /* If we can't find the dynamic linker's base structure, this |
954 | must not be a dynamically linked executable. Hmm. */ | |
955 | if (! debug_base) | |
956 | return svr4_default_sos (); | |
13437d4b KB |
957 | |
958 | /* Walk the inferior's link map list, and build our list of | |
959 | `struct so_list' nodes. */ | |
e4cd0d6a | 960 | lm = solib_svr4_r_map (); |
34439770 | 961 | |
13437d4b KB |
962 | while (lm) |
963 | { | |
4b188b9f | 964 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
f4456994 | 965 | struct so_list *new = XZALLOC (struct so_list); |
b8c9b27d | 966 | struct cleanup *old_chain = make_cleanup (xfree, new); |
13437d4b | 967 | |
13437d4b | 968 | new->lm_info = xmalloc (sizeof (struct lm_info)); |
b8c9b27d | 969 | make_cleanup (xfree, new->lm_info); |
13437d4b | 970 | |
831004b7 | 971 | new->lm_info->l_addr = (CORE_ADDR)-1; |
93a57060 | 972 | new->lm_info->lm_addr = lm; |
f4456994 | 973 | new->lm_info->lm = xzalloc (lmo->link_map_size); |
b8c9b27d | 974 | make_cleanup (xfree, new->lm_info->lm); |
13437d4b KB |
975 | |
976 | read_memory (lm, new->lm_info->lm, lmo->link_map_size); | |
977 | ||
978 | lm = LM_NEXT (new); | |
979 | ||
980 | /* For SVR4 versions, the first entry in the link map is for the | |
981 | inferior executable, so we must ignore it. For some versions of | |
982 | SVR4, it has no name. For others (Solaris 2.3 for example), it | |
983 | does have a name, so we can no longer use a missing name to | |
984 | decide when to ignore it. */ | |
e4cd0d6a | 985 | if (IGNORE_FIRST_LINK_MAP_ENTRY (new) && ldsomap == 0) |
93a57060 DJ |
986 | { |
987 | main_lm_addr = new->lm_info->lm_addr; | |
988 | free_so (new); | |
989 | } | |
13437d4b KB |
990 | else |
991 | { | |
992 | int errcode; | |
993 | char *buffer; | |
994 | ||
995 | /* Extract this shared object's name. */ | |
996 | target_read_string (LM_NAME (new), &buffer, | |
997 | SO_NAME_MAX_PATH_SIZE - 1, &errcode); | |
998 | if (errcode != 0) | |
8a3fe4f8 AC |
999 | warning (_("Can't read pathname for load map: %s."), |
1000 | safe_strerror (errcode)); | |
13437d4b KB |
1001 | else |
1002 | { | |
1003 | strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1); | |
1004 | new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; | |
13437d4b KB |
1005 | strcpy (new->so_original_name, new->so_name); |
1006 | } | |
ea5bf0a1 | 1007 | xfree (buffer); |
13437d4b KB |
1008 | |
1009 | /* If this entry has no name, or its name matches the name | |
1010 | for the main executable, don't include it in the list. */ | |
1011 | if (! new->so_name[0] | |
1012 | || match_main (new->so_name)) | |
1013 | free_so (new); | |
1014 | else | |
1015 | { | |
1016 | new->next = 0; | |
1017 | *link_ptr = new; | |
1018 | link_ptr = &new->next; | |
1019 | } | |
1020 | } | |
1021 | ||
e4cd0d6a MK |
1022 | /* On Solaris, the dynamic linker is not in the normal list of |
1023 | shared objects, so make sure we pick it up too. Having | |
1024 | symbol information for the dynamic linker is quite crucial | |
1025 | for skipping dynamic linker resolver code. */ | |
1026 | if (lm == 0 && ldsomap == 0) | |
1027 | lm = ldsomap = solib_svr4_r_ldsomap (); | |
1028 | ||
13437d4b KB |
1029 | discard_cleanups (old_chain); |
1030 | } | |
1031 | ||
34439770 DJ |
1032 | if (head == NULL) |
1033 | return svr4_default_sos (); | |
1034 | ||
13437d4b KB |
1035 | return head; |
1036 | } | |
1037 | ||
93a57060 | 1038 | /* Get the address of the link_map for a given OBJFILE. */ |
bc4a16ae EZ |
1039 | |
1040 | CORE_ADDR | |
1041 | svr4_fetch_objfile_link_map (struct objfile *objfile) | |
1042 | { | |
93a57060 | 1043 | struct so_list *so; |
bc4a16ae | 1044 | |
93a57060 DJ |
1045 | /* Cause svr4_current_sos() to be run if it hasn't been already. */ |
1046 | if (main_lm_addr == 0) | |
1047 | solib_add (NULL, 0, ¤t_target, auto_solib_add); | |
bc4a16ae | 1048 | |
93a57060 DJ |
1049 | /* svr4_current_sos() will set main_lm_addr for the main executable. */ |
1050 | if (objfile == symfile_objfile) | |
1051 | return main_lm_addr; | |
1052 | ||
1053 | /* The other link map addresses may be found by examining the list | |
1054 | of shared libraries. */ | |
1055 | for (so = master_so_list (); so; so = so->next) | |
1056 | if (so->objfile == objfile) | |
1057 | return so->lm_info->lm_addr; | |
1058 | ||
1059 | /* Not found! */ | |
bc4a16ae EZ |
1060 | return 0; |
1061 | } | |
13437d4b KB |
1062 | |
1063 | /* On some systems, the only way to recognize the link map entry for | |
1064 | the main executable file is by looking at its name. Return | |
1065 | non-zero iff SONAME matches one of the known main executable names. */ | |
1066 | ||
1067 | static int | |
1068 | match_main (char *soname) | |
1069 | { | |
1070 | char **mainp; | |
1071 | ||
1072 | for (mainp = main_name_list; *mainp != NULL; mainp++) | |
1073 | { | |
1074 | if (strcmp (soname, *mainp) == 0) | |
1075 | return (1); | |
1076 | } | |
1077 | ||
1078 | return (0); | |
1079 | } | |
1080 | ||
13437d4b KB |
1081 | /* Return 1 if PC lies in the dynamic symbol resolution code of the |
1082 | SVR4 run time loader. */ | |
13437d4b KB |
1083 | static CORE_ADDR interp_text_sect_low; |
1084 | static CORE_ADDR interp_text_sect_high; | |
1085 | static CORE_ADDR interp_plt_sect_low; | |
1086 | static CORE_ADDR interp_plt_sect_high; | |
1087 | ||
7d522c90 | 1088 | int |
d7fa2ae2 | 1089 | svr4_in_dynsym_resolve_code (CORE_ADDR pc) |
13437d4b KB |
1090 | { |
1091 | return ((pc >= interp_text_sect_low && pc < interp_text_sect_high) | |
1092 | || (pc >= interp_plt_sect_low && pc < interp_plt_sect_high) | |
1093 | || in_plt_section (pc, NULL)); | |
1094 | } | |
13437d4b | 1095 | |
2f4950cd AC |
1096 | /* Given an executable's ABFD and target, compute the entry-point |
1097 | address. */ | |
1098 | ||
1099 | static CORE_ADDR | |
1100 | exec_entry_point (struct bfd *abfd, struct target_ops *targ) | |
1101 | { | |
1102 | /* KevinB wrote ... for most targets, the address returned by | |
1103 | bfd_get_start_address() is the entry point for the start | |
1104 | function. But, for some targets, bfd_get_start_address() returns | |
1105 | the address of a function descriptor from which the entry point | |
1106 | address may be extracted. This address is extracted by | |
1107 | gdbarch_convert_from_func_ptr_addr(). The method | |
1108 | gdbarch_convert_from_func_ptr_addr() is the merely the identify | |
1109 | function for targets which don't use function descriptors. */ | |
1cf3db46 | 1110 | return gdbarch_convert_from_func_ptr_addr (target_gdbarch, |
2f4950cd AC |
1111 | bfd_get_start_address (abfd), |
1112 | targ); | |
1113 | } | |
13437d4b KB |
1114 | |
1115 | /* | |
1116 | ||
1117 | LOCAL FUNCTION | |
1118 | ||
1119 | enable_break -- arrange for dynamic linker to hit breakpoint | |
1120 | ||
1121 | SYNOPSIS | |
1122 | ||
1123 | int enable_break (void) | |
1124 | ||
1125 | DESCRIPTION | |
1126 | ||
1127 | Both the SunOS and the SVR4 dynamic linkers have, as part of their | |
1128 | debugger interface, support for arranging for the inferior to hit | |
1129 | a breakpoint after mapping in the shared libraries. This function | |
1130 | enables that breakpoint. | |
1131 | ||
1132 | For SunOS, there is a special flag location (in_debugger) which we | |
1133 | set to 1. When the dynamic linker sees this flag set, it will set | |
1134 | a breakpoint at a location known only to itself, after saving the | |
1135 | original contents of that place and the breakpoint address itself, | |
1136 | in it's own internal structures. When we resume the inferior, it | |
1137 | will eventually take a SIGTRAP when it runs into the breakpoint. | |
1138 | We handle this (in a different place) by restoring the contents of | |
1139 | the breakpointed location (which is only known after it stops), | |
1140 | chasing around to locate the shared libraries that have been | |
1141 | loaded, then resuming. | |
1142 | ||
1143 | For SVR4, the debugger interface structure contains a member (r_brk) | |
1144 | which is statically initialized at the time the shared library is | |
1145 | built, to the offset of a function (_r_debug_state) which is guaran- | |
1146 | teed to be called once before mapping in a library, and again when | |
1147 | the mapping is complete. At the time we are examining this member, | |
1148 | it contains only the unrelocated offset of the function, so we have | |
1149 | to do our own relocation. Later, when the dynamic linker actually | |
1150 | runs, it relocates r_brk to be the actual address of _r_debug_state(). | |
1151 | ||
1152 | The debugger interface structure also contains an enumeration which | |
1153 | is set to either RT_ADD or RT_DELETE prior to changing the mapping, | |
1154 | depending upon whether or not the library is being mapped or unmapped, | |
1155 | and then set to RT_CONSISTENT after the library is mapped/unmapped. | |
1156 | */ | |
1157 | ||
1158 | static int | |
1159 | enable_break (void) | |
1160 | { | |
13437d4b KB |
1161 | struct minimal_symbol *msymbol; |
1162 | char **bkpt_namep; | |
1163 | asection *interp_sect; | |
97ec2c2f | 1164 | gdb_byte *interp_name; |
7cd25cfc | 1165 | CORE_ADDR sym_addr; |
13437d4b KB |
1166 | |
1167 | /* First, remove all the solib event breakpoints. Their addresses | |
1168 | may have changed since the last time we ran the program. */ | |
1169 | remove_solib_event_breakpoints (); | |
1170 | ||
13437d4b KB |
1171 | interp_text_sect_low = interp_text_sect_high = 0; |
1172 | interp_plt_sect_low = interp_plt_sect_high = 0; | |
1173 | ||
7cd25cfc DJ |
1174 | /* If we already have a shared library list in the target, and |
1175 | r_debug contains r_brk, set the breakpoint there - this should | |
1176 | mean r_brk has already been relocated. Assume the dynamic linker | |
1177 | is the object containing r_brk. */ | |
1178 | ||
1179 | solib_add (NULL, 0, ¤t_target, auto_solib_add); | |
1180 | sym_addr = 0; | |
1181 | if (debug_base && solib_svr4_r_map () != 0) | |
1182 | sym_addr = solib_svr4_r_brk (); | |
1183 | ||
1184 | if (sym_addr != 0) | |
1185 | { | |
1186 | struct obj_section *os; | |
1187 | ||
b36ec657 | 1188 | sym_addr = gdbarch_addr_bits_remove |
1cf3db46 | 1189 | (target_gdbarch, gdbarch_convert_from_func_ptr_addr (target_gdbarch, |
b36ec657 DJ |
1190 | sym_addr, |
1191 | ¤t_target)); | |
1192 | ||
7cd25cfc DJ |
1193 | os = find_pc_section (sym_addr); |
1194 | if (os != NULL) | |
1195 | { | |
1196 | /* Record the relocated start and end address of the dynamic linker | |
1197 | text and plt section for svr4_in_dynsym_resolve_code. */ | |
1198 | bfd *tmp_bfd; | |
1199 | CORE_ADDR load_addr; | |
1200 | ||
1201 | tmp_bfd = os->objfile->obfd; | |
1202 | load_addr = ANOFFSET (os->objfile->section_offsets, | |
1203 | os->objfile->sect_index_text); | |
1204 | ||
1205 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); | |
1206 | if (interp_sect) | |
1207 | { | |
1208 | interp_text_sect_low = | |
1209 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
1210 | interp_text_sect_high = | |
1211 | interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
1212 | } | |
1213 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); | |
1214 | if (interp_sect) | |
1215 | { | |
1216 | interp_plt_sect_low = | |
1217 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
1218 | interp_plt_sect_high = | |
1219 | interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
1220 | } | |
1221 | ||
1222 | create_solib_event_breakpoint (sym_addr); | |
1223 | return 1; | |
1224 | } | |
1225 | } | |
1226 | ||
97ec2c2f | 1227 | /* Find the program interpreter; if not found, warn the user and drop |
13437d4b | 1228 | into the old breakpoint at symbol code. */ |
97ec2c2f UW |
1229 | interp_name = find_program_interpreter (); |
1230 | if (interp_name) | |
13437d4b | 1231 | { |
8ad2fcde KB |
1232 | CORE_ADDR load_addr = 0; |
1233 | int load_addr_found = 0; | |
2ec9a4f8 | 1234 | int loader_found_in_list = 0; |
f8766ec1 | 1235 | struct so_list *so; |
e4f7b8c8 | 1236 | bfd *tmp_bfd = NULL; |
2f4950cd | 1237 | struct target_ops *tmp_bfd_target; |
f1838a98 | 1238 | volatile struct gdb_exception ex; |
13437d4b | 1239 | |
7cd25cfc | 1240 | sym_addr = 0; |
13437d4b KB |
1241 | |
1242 | /* Now we need to figure out where the dynamic linker was | |
1243 | loaded so that we can load its symbols and place a breakpoint | |
1244 | in the dynamic linker itself. | |
1245 | ||
1246 | This address is stored on the stack. However, I've been unable | |
1247 | to find any magic formula to find it for Solaris (appears to | |
1248 | be trivial on GNU/Linux). Therefore, we have to try an alternate | |
1249 | mechanism to find the dynamic linker's base address. */ | |
e4f7b8c8 | 1250 | |
f1838a98 UW |
1251 | TRY_CATCH (ex, RETURN_MASK_ALL) |
1252 | { | |
97ec2c2f | 1253 | tmp_bfd = solib_bfd_open (interp_name); |
f1838a98 | 1254 | } |
13437d4b KB |
1255 | if (tmp_bfd == NULL) |
1256 | goto bkpt_at_symbol; | |
1257 | ||
2f4950cd AC |
1258 | /* Now convert the TMP_BFD into a target. That way target, as |
1259 | well as BFD operations can be used. Note that closing the | |
1260 | target will also close the underlying bfd. */ | |
1261 | tmp_bfd_target = target_bfd_reopen (tmp_bfd); | |
1262 | ||
f8766ec1 KB |
1263 | /* On a running target, we can get the dynamic linker's base |
1264 | address from the shared library table. */ | |
f8766ec1 KB |
1265 | so = master_so_list (); |
1266 | while (so) | |
8ad2fcde | 1267 | { |
97ec2c2f | 1268 | if (svr4_same_1 (interp_name, so->so_original_name)) |
8ad2fcde KB |
1269 | { |
1270 | load_addr_found = 1; | |
2ec9a4f8 | 1271 | loader_found_in_list = 1; |
cc10cae3 | 1272 | load_addr = LM_ADDR_CHECK (so, tmp_bfd); |
8ad2fcde KB |
1273 | break; |
1274 | } | |
f8766ec1 | 1275 | so = so->next; |
8ad2fcde KB |
1276 | } |
1277 | ||
8d4e36ba JB |
1278 | /* If we were not able to find the base address of the loader |
1279 | from our so_list, then try using the AT_BASE auxilliary entry. */ | |
1280 | if (!load_addr_found) | |
1281 | if (target_auxv_search (¤t_target, AT_BASE, &load_addr) > 0) | |
1282 | load_addr_found = 1; | |
1283 | ||
8ad2fcde KB |
1284 | /* Otherwise we find the dynamic linker's base address by examining |
1285 | the current pc (which should point at the entry point for the | |
8d4e36ba JB |
1286 | dynamic linker) and subtracting the offset of the entry point. |
1287 | ||
1288 | This is more fragile than the previous approaches, but is a good | |
1289 | fallback method because it has actually been working well in | |
1290 | most cases. */ | |
8ad2fcde | 1291 | if (!load_addr_found) |
2ec9a4f8 DJ |
1292 | load_addr = (read_pc () |
1293 | - exec_entry_point (tmp_bfd, tmp_bfd_target)); | |
1294 | ||
1295 | if (!loader_found_in_list) | |
34439770 | 1296 | { |
97ec2c2f | 1297 | debug_loader_name = xstrdup (interp_name); |
34439770 DJ |
1298 | debug_loader_offset_p = 1; |
1299 | debug_loader_offset = load_addr; | |
2bbe3cc1 | 1300 | solib_add (NULL, 0, ¤t_target, auto_solib_add); |
34439770 | 1301 | } |
13437d4b KB |
1302 | |
1303 | /* Record the relocated start and end address of the dynamic linker | |
d7fa2ae2 | 1304 | text and plt section for svr4_in_dynsym_resolve_code. */ |
13437d4b KB |
1305 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
1306 | if (interp_sect) | |
1307 | { | |
1308 | interp_text_sect_low = | |
1309 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
1310 | interp_text_sect_high = | |
1311 | interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
1312 | } | |
1313 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); | |
1314 | if (interp_sect) | |
1315 | { | |
1316 | interp_plt_sect_low = | |
1317 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
1318 | interp_plt_sect_high = | |
1319 | interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
1320 | } | |
1321 | ||
1322 | /* Now try to set a breakpoint in the dynamic linker. */ | |
1323 | for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) | |
1324 | { | |
2bbe3cc1 | 1325 | sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep); |
13437d4b KB |
1326 | if (sym_addr != 0) |
1327 | break; | |
1328 | } | |
1329 | ||
2bbe3cc1 DJ |
1330 | if (sym_addr != 0) |
1331 | /* Convert 'sym_addr' from a function pointer to an address. | |
1332 | Because we pass tmp_bfd_target instead of the current | |
1333 | target, this will always produce an unrelocated value. */ | |
1cf3db46 | 1334 | sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch, |
2bbe3cc1 DJ |
1335 | sym_addr, |
1336 | tmp_bfd_target); | |
1337 | ||
2f4950cd AC |
1338 | /* We're done with both the temporary bfd and target. Remember, |
1339 | closing the target closes the underlying bfd. */ | |
1340 | target_close (tmp_bfd_target, 0); | |
13437d4b KB |
1341 | |
1342 | if (sym_addr != 0) | |
1343 | { | |
1344 | create_solib_event_breakpoint (load_addr + sym_addr); | |
97ec2c2f | 1345 | xfree (interp_name); |
13437d4b KB |
1346 | return 1; |
1347 | } | |
1348 | ||
1349 | /* For whatever reason we couldn't set a breakpoint in the dynamic | |
1350 | linker. Warn and drop into the old code. */ | |
1351 | bkpt_at_symbol: | |
97ec2c2f | 1352 | xfree (interp_name); |
82d03102 PG |
1353 | warning (_("Unable to find dynamic linker breakpoint function.\n" |
1354 | "GDB will be unable to debug shared library initializers\n" | |
1355 | "and track explicitly loaded dynamic code.")); | |
13437d4b | 1356 | } |
13437d4b | 1357 | |
e499d0f1 DJ |
1358 | /* Scan through the lists of symbols, trying to look up the symbol and |
1359 | set a breakpoint there. Terminate loop when we/if we succeed. */ | |
1360 | ||
1361 | for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) | |
1362 | { | |
1363 | msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); | |
1364 | if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) | |
1365 | { | |
1366 | create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol)); | |
1367 | return 1; | |
1368 | } | |
1369 | } | |
13437d4b | 1370 | |
13437d4b KB |
1371 | for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++) |
1372 | { | |
1373 | msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); | |
1374 | if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) | |
1375 | { | |
1376 | create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol)); | |
1377 | return 1; | |
1378 | } | |
1379 | } | |
542c95c2 | 1380 | return 0; |
13437d4b KB |
1381 | } |
1382 | ||
1383 | /* | |
1384 | ||
1385 | LOCAL FUNCTION | |
1386 | ||
1387 | special_symbol_handling -- additional shared library symbol handling | |
1388 | ||
1389 | SYNOPSIS | |
1390 | ||
1391 | void special_symbol_handling () | |
1392 | ||
1393 | DESCRIPTION | |
1394 | ||
1395 | Once the symbols from a shared object have been loaded in the usual | |
1396 | way, we are called to do any system specific symbol handling that | |
1397 | is needed. | |
1398 | ||
ab31aa69 | 1399 | For SunOS4, this consisted of grunging around in the dynamic |
13437d4b KB |
1400 | linkers structures to find symbol definitions for "common" symbols |
1401 | and adding them to the minimal symbol table for the runtime common | |
1402 | objfile. | |
1403 | ||
ab31aa69 KB |
1404 | However, for SVR4, there's nothing to do. |
1405 | ||
13437d4b KB |
1406 | */ |
1407 | ||
1408 | static void | |
1409 | svr4_special_symbol_handling (void) | |
1410 | { | |
13437d4b KB |
1411 | } |
1412 | ||
e2a44558 KB |
1413 | /* Relocate the main executable. This function should be called upon |
1414 | stopping the inferior process at the entry point to the program. | |
1415 | The entry point from BFD is compared to the PC and if they are | |
1416 | different, the main executable is relocated by the proper amount. | |
1417 | ||
1418 | As written it will only attempt to relocate executables which | |
1419 | lack interpreter sections. It seems likely that only dynamic | |
1420 | linker executables will get relocated, though it should work | |
1421 | properly for a position-independent static executable as well. */ | |
1422 | ||
1423 | static void | |
1424 | svr4_relocate_main_executable (void) | |
1425 | { | |
1426 | asection *interp_sect; | |
1427 | CORE_ADDR pc = read_pc (); | |
1428 | ||
1429 | /* Decide if the objfile needs to be relocated. As indicated above, | |
1430 | we will only be here when execution is stopped at the beginning | |
1431 | of the program. Relocation is necessary if the address at which | |
1432 | we are presently stopped differs from the start address stored in | |
1433 | the executable AND there's no interpreter section. The condition | |
1434 | regarding the interpreter section is very important because if | |
1435 | there *is* an interpreter section, execution will begin there | |
1436 | instead. When there is an interpreter section, the start address | |
1437 | is (presumably) used by the interpreter at some point to start | |
1438 | execution of the program. | |
1439 | ||
1440 | If there is an interpreter, it is normal for it to be set to an | |
1441 | arbitrary address at the outset. The job of finding it is | |
1442 | handled in enable_break(). | |
1443 | ||
1444 | So, to summarize, relocations are necessary when there is no | |
1445 | interpreter section and the start address obtained from the | |
1446 | executable is different from the address at which GDB is | |
1447 | currently stopped. | |
1448 | ||
1449 | [ The astute reader will note that we also test to make sure that | |
1450 | the executable in question has the DYNAMIC flag set. It is my | |
1451 | opinion that this test is unnecessary (undesirable even). It | |
1452 | was added to avoid inadvertent relocation of an executable | |
1453 | whose e_type member in the ELF header is not ET_DYN. There may | |
1454 | be a time in the future when it is desirable to do relocations | |
1455 | on other types of files as well in which case this condition | |
1456 | should either be removed or modified to accomodate the new file | |
1457 | type. (E.g, an ET_EXEC executable which has been built to be | |
1458 | position-independent could safely be relocated by the OS if | |
1459 | desired. It is true that this violates the ABI, but the ABI | |
1460 | has been known to be bent from time to time.) - Kevin, Nov 2000. ] | |
1461 | */ | |
1462 | ||
1463 | interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); | |
1464 | if (interp_sect == NULL | |
1465 | && (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0 | |
2f4950cd | 1466 | && (exec_entry_point (exec_bfd, &exec_ops) != pc)) |
e2a44558 KB |
1467 | { |
1468 | struct cleanup *old_chain; | |
1469 | struct section_offsets *new_offsets; | |
1470 | int i, changed; | |
1471 | CORE_ADDR displacement; | |
1472 | ||
1473 | /* It is necessary to relocate the objfile. The amount to | |
1474 | relocate by is simply the address at which we are stopped | |
1475 | minus the starting address from the executable. | |
1476 | ||
1477 | We relocate all of the sections by the same amount. This | |
1478 | behavior is mandated by recent editions of the System V ABI. | |
1479 | According to the System V Application Binary Interface, | |
1480 | Edition 4.1, page 5-5: | |
1481 | ||
1482 | ... Though the system chooses virtual addresses for | |
1483 | individual processes, it maintains the segments' relative | |
1484 | positions. Because position-independent code uses relative | |
1485 | addressesing between segments, the difference between | |
1486 | virtual addresses in memory must match the difference | |
1487 | between virtual addresses in the file. The difference | |
1488 | between the virtual address of any segment in memory and | |
1489 | the corresponding virtual address in the file is thus a | |
1490 | single constant value for any one executable or shared | |
1491 | object in a given process. This difference is the base | |
1492 | address. One use of the base address is to relocate the | |
1493 | memory image of the program during dynamic linking. | |
1494 | ||
1495 | The same language also appears in Edition 4.0 of the System V | |
1496 | ABI and is left unspecified in some of the earlier editions. */ | |
1497 | ||
2f4950cd | 1498 | displacement = pc - exec_entry_point (exec_bfd, &exec_ops); |
e2a44558 KB |
1499 | changed = 0; |
1500 | ||
13fc0c2f KB |
1501 | new_offsets = xcalloc (symfile_objfile->num_sections, |
1502 | sizeof (struct section_offsets)); | |
b8c9b27d | 1503 | old_chain = make_cleanup (xfree, new_offsets); |
e2a44558 KB |
1504 | |
1505 | for (i = 0; i < symfile_objfile->num_sections; i++) | |
1506 | { | |
1507 | if (displacement != ANOFFSET (symfile_objfile->section_offsets, i)) | |
1508 | changed = 1; | |
1509 | new_offsets->offsets[i] = displacement; | |
1510 | } | |
1511 | ||
1512 | if (changed) | |
1513 | objfile_relocate (symfile_objfile, new_offsets); | |
1514 | ||
1515 | do_cleanups (old_chain); | |
1516 | } | |
1517 | } | |
1518 | ||
13437d4b KB |
1519 | /* |
1520 | ||
1521 | GLOBAL FUNCTION | |
1522 | ||
1523 | svr4_solib_create_inferior_hook -- shared library startup support | |
1524 | ||
1525 | SYNOPSIS | |
1526 | ||
7095b863 | 1527 | void svr4_solib_create_inferior_hook () |
13437d4b KB |
1528 | |
1529 | DESCRIPTION | |
1530 | ||
1531 | When gdb starts up the inferior, it nurses it along (through the | |
1532 | shell) until it is ready to execute it's first instruction. At this | |
1533 | point, this function gets called via expansion of the macro | |
1534 | SOLIB_CREATE_INFERIOR_HOOK. | |
1535 | ||
1536 | For SunOS executables, this first instruction is typically the | |
1537 | one at "_start", or a similar text label, regardless of whether | |
1538 | the executable is statically or dynamically linked. The runtime | |
1539 | startup code takes care of dynamically linking in any shared | |
1540 | libraries, once gdb allows the inferior to continue. | |
1541 | ||
1542 | For SVR4 executables, this first instruction is either the first | |
1543 | instruction in the dynamic linker (for dynamically linked | |
1544 | executables) or the instruction at "start" for statically linked | |
1545 | executables. For dynamically linked executables, the system | |
1546 | first exec's /lib/libc.so.N, which contains the dynamic linker, | |
1547 | and starts it running. The dynamic linker maps in any needed | |
1548 | shared libraries, maps in the actual user executable, and then | |
1549 | jumps to "start" in the user executable. | |
1550 | ||
1551 | For both SunOS shared libraries, and SVR4 shared libraries, we | |
1552 | can arrange to cooperate with the dynamic linker to discover the | |
1553 | names of shared libraries that are dynamically linked, and the | |
1554 | base addresses to which they are linked. | |
1555 | ||
1556 | This function is responsible for discovering those names and | |
1557 | addresses, and saving sufficient information about them to allow | |
1558 | their symbols to be read at a later time. | |
1559 | ||
1560 | FIXME | |
1561 | ||
1562 | Between enable_break() and disable_break(), this code does not | |
1563 | properly handle hitting breakpoints which the user might have | |
1564 | set in the startup code or in the dynamic linker itself. Proper | |
1565 | handling will probably have to wait until the implementation is | |
1566 | changed to use the "breakpoint handler function" method. | |
1567 | ||
1568 | Also, what if child has exit()ed? Must exit loop somehow. | |
1569 | */ | |
1570 | ||
e2a44558 | 1571 | static void |
13437d4b KB |
1572 | svr4_solib_create_inferior_hook (void) |
1573 | { | |
d6b48e9c | 1574 | struct inferior *inf; |
2020b7ab PA |
1575 | struct thread_info *tp; |
1576 | ||
e2a44558 KB |
1577 | /* Relocate the main executable if necessary. */ |
1578 | svr4_relocate_main_executable (); | |
1579 | ||
d5a921c9 | 1580 | if (!svr4_have_link_map_offsets ()) |
513f5903 | 1581 | return; |
d5a921c9 | 1582 | |
13437d4b | 1583 | if (!enable_break ()) |
542c95c2 | 1584 | return; |
13437d4b | 1585 | |
ab31aa69 KB |
1586 | #if defined(_SCO_DS) |
1587 | /* SCO needs the loop below, other systems should be using the | |
13437d4b KB |
1588 | special shared library breakpoints and the shared library breakpoint |
1589 | service routine. | |
1590 | ||
1591 | Now run the target. It will eventually hit the breakpoint, at | |
1592 | which point all of the libraries will have been mapped in and we | |
1593 | can go groveling around in the dynamic linker structures to find | |
1594 | out what we need to know about them. */ | |
1595 | ||
d6b48e9c | 1596 | inf = current_inferior (); |
2020b7ab PA |
1597 | tp = inferior_thread (); |
1598 | ||
13437d4b | 1599 | clear_proceed_status (); |
d6b48e9c | 1600 | inf->stop_soon = STOP_QUIETLY; |
2020b7ab | 1601 | tp->stop_signal = TARGET_SIGNAL_0; |
13437d4b KB |
1602 | do |
1603 | { | |
2020b7ab | 1604 | target_resume (pid_to_ptid (-1), 0, tp->stop_signal); |
ae123ec6 | 1605 | wait_for_inferior (0); |
13437d4b | 1606 | } |
2020b7ab | 1607 | while (tp->stop_signal != TARGET_SIGNAL_TRAP); |
d6b48e9c | 1608 | inf->stop_soon = NO_STOP_QUIETLY; |
ab31aa69 | 1609 | #endif /* defined(_SCO_DS) */ |
13437d4b KB |
1610 | } |
1611 | ||
1612 | static void | |
1613 | svr4_clear_solib (void) | |
1614 | { | |
1615 | debug_base = 0; | |
34439770 DJ |
1616 | debug_loader_offset_p = 0; |
1617 | debug_loader_offset = 0; | |
1618 | xfree (debug_loader_name); | |
1619 | debug_loader_name = NULL; | |
93a57060 | 1620 | main_lm_addr = 0; |
13437d4b KB |
1621 | } |
1622 | ||
1623 | static void | |
1624 | svr4_free_so (struct so_list *so) | |
1625 | { | |
b8c9b27d KB |
1626 | xfree (so->lm_info->lm); |
1627 | xfree (so->lm_info); | |
13437d4b KB |
1628 | } |
1629 | ||
6bb7be43 JB |
1630 | |
1631 | /* Clear any bits of ADDR that wouldn't fit in a target-format | |
1632 | data pointer. "Data pointer" here refers to whatever sort of | |
1633 | address the dynamic linker uses to manage its sections. At the | |
1634 | moment, we don't support shared libraries on any processors where | |
1635 | code and data pointers are different sizes. | |
1636 | ||
1637 | This isn't really the right solution. What we really need here is | |
1638 | a way to do arithmetic on CORE_ADDR values that respects the | |
1639 | natural pointer/address correspondence. (For example, on the MIPS, | |
1640 | converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to | |
1641 | sign-extend the value. There, simply truncating the bits above | |
819844ad | 1642 | gdbarch_ptr_bit, as we do below, is no good.) This should probably |
6bb7be43 JB |
1643 | be a new gdbarch method or something. */ |
1644 | static CORE_ADDR | |
1645 | svr4_truncate_ptr (CORE_ADDR addr) | |
1646 | { | |
1cf3db46 | 1647 | if (gdbarch_ptr_bit (target_gdbarch) == sizeof (CORE_ADDR) * 8) |
6bb7be43 JB |
1648 | /* We don't need to truncate anything, and the bit twiddling below |
1649 | will fail due to overflow problems. */ | |
1650 | return addr; | |
1651 | else | |
1cf3db46 | 1652 | return addr & (((CORE_ADDR) 1 << gdbarch_ptr_bit (target_gdbarch)) - 1); |
6bb7be43 JB |
1653 | } |
1654 | ||
1655 | ||
749499cb KB |
1656 | static void |
1657 | svr4_relocate_section_addresses (struct so_list *so, | |
1658 | struct section_table *sec) | |
1659 | { | |
cc10cae3 AO |
1660 | sec->addr = svr4_truncate_ptr (sec->addr + LM_ADDR_CHECK (so, |
1661 | sec->bfd)); | |
1662 | sec->endaddr = svr4_truncate_ptr (sec->endaddr + LM_ADDR_CHECK (so, | |
1663 | sec->bfd)); | |
749499cb | 1664 | } |
4b188b9f | 1665 | \f |
749499cb | 1666 | |
4b188b9f | 1667 | /* Architecture-specific operations. */ |
6bb7be43 | 1668 | |
4b188b9f MK |
1669 | /* Per-architecture data key. */ |
1670 | static struct gdbarch_data *solib_svr4_data; | |
e5e2b9ff | 1671 | |
4b188b9f | 1672 | struct solib_svr4_ops |
e5e2b9ff | 1673 | { |
4b188b9f MK |
1674 | /* Return a description of the layout of `struct link_map'. */ |
1675 | struct link_map_offsets *(*fetch_link_map_offsets)(void); | |
1676 | }; | |
e5e2b9ff | 1677 | |
4b188b9f | 1678 | /* Return a default for the architecture-specific operations. */ |
e5e2b9ff | 1679 | |
4b188b9f MK |
1680 | static void * |
1681 | solib_svr4_init (struct obstack *obstack) | |
e5e2b9ff | 1682 | { |
4b188b9f | 1683 | struct solib_svr4_ops *ops; |
e5e2b9ff | 1684 | |
4b188b9f | 1685 | ops = OBSTACK_ZALLOC (obstack, struct solib_svr4_ops); |
8d005789 | 1686 | ops->fetch_link_map_offsets = NULL; |
4b188b9f | 1687 | return ops; |
e5e2b9ff KB |
1688 | } |
1689 | ||
4b188b9f | 1690 | /* Set the architecture-specific `struct link_map_offsets' fetcher for |
7e3cb44c | 1691 | GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */ |
1c4dcb57 | 1692 | |
21479ded | 1693 | void |
e5e2b9ff KB |
1694 | set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch, |
1695 | struct link_map_offsets *(*flmo) (void)) | |
21479ded | 1696 | { |
4b188b9f MK |
1697 | struct solib_svr4_ops *ops = gdbarch_data (gdbarch, solib_svr4_data); |
1698 | ||
1699 | ops->fetch_link_map_offsets = flmo; | |
7e3cb44c UW |
1700 | |
1701 | set_solib_ops (gdbarch, &svr4_so_ops); | |
21479ded KB |
1702 | } |
1703 | ||
4b188b9f MK |
1704 | /* Fetch a link_map_offsets structure using the architecture-specific |
1705 | `struct link_map_offsets' fetcher. */ | |
1c4dcb57 | 1706 | |
4b188b9f MK |
1707 | static struct link_map_offsets * |
1708 | svr4_fetch_link_map_offsets (void) | |
21479ded | 1709 | { |
1cf3db46 | 1710 | struct solib_svr4_ops *ops = gdbarch_data (target_gdbarch, solib_svr4_data); |
4b188b9f MK |
1711 | |
1712 | gdb_assert (ops->fetch_link_map_offsets); | |
1713 | return ops->fetch_link_map_offsets (); | |
21479ded KB |
1714 | } |
1715 | ||
4b188b9f MK |
1716 | /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */ |
1717 | ||
1718 | static int | |
1719 | svr4_have_link_map_offsets (void) | |
1720 | { | |
1cf3db46 | 1721 | struct solib_svr4_ops *ops = gdbarch_data (target_gdbarch, solib_svr4_data); |
4b188b9f MK |
1722 | return (ops->fetch_link_map_offsets != NULL); |
1723 | } | |
1724 | \f | |
1725 | ||
e4bbbda8 MK |
1726 | /* Most OS'es that have SVR4-style ELF dynamic libraries define a |
1727 | `struct r_debug' and a `struct link_map' that are binary compatible | |
1728 | with the origional SVR4 implementation. */ | |
1729 | ||
1730 | /* Fetch (and possibly build) an appropriate `struct link_map_offsets' | |
1731 | for an ILP32 SVR4 system. */ | |
1732 | ||
1733 | struct link_map_offsets * | |
1734 | svr4_ilp32_fetch_link_map_offsets (void) | |
1735 | { | |
1736 | static struct link_map_offsets lmo; | |
1737 | static struct link_map_offsets *lmp = NULL; | |
1738 | ||
1739 | if (lmp == NULL) | |
1740 | { | |
1741 | lmp = &lmo; | |
1742 | ||
e4cd0d6a MK |
1743 | lmo.r_version_offset = 0; |
1744 | lmo.r_version_size = 4; | |
e4bbbda8 | 1745 | lmo.r_map_offset = 4; |
7cd25cfc | 1746 | lmo.r_brk_offset = 8; |
e4cd0d6a | 1747 | lmo.r_ldsomap_offset = 20; |
e4bbbda8 MK |
1748 | |
1749 | /* Everything we need is in the first 20 bytes. */ | |
1750 | lmo.link_map_size = 20; | |
1751 | lmo.l_addr_offset = 0; | |
e4bbbda8 | 1752 | lmo.l_name_offset = 4; |
cc10cae3 | 1753 | lmo.l_ld_offset = 8; |
e4bbbda8 | 1754 | lmo.l_next_offset = 12; |
e4bbbda8 | 1755 | lmo.l_prev_offset = 16; |
e4bbbda8 MK |
1756 | } |
1757 | ||
1758 | return lmp; | |
1759 | } | |
1760 | ||
1761 | /* Fetch (and possibly build) an appropriate `struct link_map_offsets' | |
1762 | for an LP64 SVR4 system. */ | |
1763 | ||
1764 | struct link_map_offsets * | |
1765 | svr4_lp64_fetch_link_map_offsets (void) | |
1766 | { | |
1767 | static struct link_map_offsets lmo; | |
1768 | static struct link_map_offsets *lmp = NULL; | |
1769 | ||
1770 | if (lmp == NULL) | |
1771 | { | |
1772 | lmp = &lmo; | |
1773 | ||
e4cd0d6a MK |
1774 | lmo.r_version_offset = 0; |
1775 | lmo.r_version_size = 4; | |
e4bbbda8 | 1776 | lmo.r_map_offset = 8; |
7cd25cfc | 1777 | lmo.r_brk_offset = 16; |
e4cd0d6a | 1778 | lmo.r_ldsomap_offset = 40; |
e4bbbda8 MK |
1779 | |
1780 | /* Everything we need is in the first 40 bytes. */ | |
1781 | lmo.link_map_size = 40; | |
1782 | lmo.l_addr_offset = 0; | |
e4bbbda8 | 1783 | lmo.l_name_offset = 8; |
cc10cae3 | 1784 | lmo.l_ld_offset = 16; |
e4bbbda8 | 1785 | lmo.l_next_offset = 24; |
e4bbbda8 | 1786 | lmo.l_prev_offset = 32; |
e4bbbda8 MK |
1787 | } |
1788 | ||
1789 | return lmp; | |
1790 | } | |
1791 | \f | |
1792 | ||
7d522c90 | 1793 | struct target_so_ops svr4_so_ops; |
13437d4b | 1794 | |
3a40aaa0 UW |
1795 | /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a |
1796 | different rule for symbol lookup. The lookup begins here in the DSO, not in | |
1797 | the main executable. */ | |
1798 | ||
1799 | static struct symbol * | |
1800 | elf_lookup_lib_symbol (const struct objfile *objfile, | |
1801 | const char *name, | |
1802 | const char *linkage_name, | |
21b556f4 | 1803 | const domain_enum domain) |
3a40aaa0 UW |
1804 | { |
1805 | if (objfile->obfd == NULL | |
1806 | || scan_dyntag (DT_SYMBOLIC, objfile->obfd, NULL) != 1) | |
1807 | return NULL; | |
1808 | ||
65728c26 | 1809 | return lookup_global_symbol_from_objfile |
21b556f4 | 1810 | (objfile, name, linkage_name, domain); |
3a40aaa0 UW |
1811 | } |
1812 | ||
a78f21af AC |
1813 | extern initialize_file_ftype _initialize_svr4_solib; /* -Wmissing-prototypes */ |
1814 | ||
13437d4b KB |
1815 | void |
1816 | _initialize_svr4_solib (void) | |
1817 | { | |
4b188b9f MK |
1818 | solib_svr4_data = gdbarch_data_register_pre_init (solib_svr4_init); |
1819 | ||
749499cb | 1820 | svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses; |
13437d4b KB |
1821 | svr4_so_ops.free_so = svr4_free_so; |
1822 | svr4_so_ops.clear_solib = svr4_clear_solib; | |
1823 | svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook; | |
1824 | svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling; | |
1825 | svr4_so_ops.current_sos = svr4_current_sos; | |
1826 | svr4_so_ops.open_symbol_file_object = open_symbol_file_object; | |
d7fa2ae2 | 1827 | svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code; |
3a40aaa0 | 1828 | svr4_so_ops.lookup_lib_global_symbol = elf_lookup_lib_symbol; |
a7c02bc8 | 1829 | svr4_so_ops.same = svr4_same; |
13437d4b | 1830 | } |