Commit | Line | Data |
---|---|---|
ab31aa69 | 1 | /* Handle SVR4 shared libraries for GDB, the GNU Debugger. |
2f4950cd | 2 | |
197e01b6 | 3 | Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, |
e4cd0d6a | 4 | 2000, 2001, 2003, 2004, 2005, 2006 |
e4bbbda8 | 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 | |
11 | the Free Software Foundation; either version 2 of the License, or | |
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 | |
20 | along with this program; if not, write to the Free Software | |
197e01b6 EZ |
21 | Foundation, Inc., 51 Franklin Street, Fifth Floor, |
22 | Boston, MA 02110-1301, USA. */ | |
13437d4b | 23 | |
13437d4b KB |
24 | #include "defs.h" |
25 | ||
13437d4b | 26 | #include "elf/external.h" |
21479ded | 27 | #include "elf/common.h" |
f7856c8f | 28 | #include "elf/mips.h" |
13437d4b KB |
29 | |
30 | #include "symtab.h" | |
31 | #include "bfd.h" | |
32 | #include "symfile.h" | |
33 | #include "objfiles.h" | |
34 | #include "gdbcore.h" | |
13437d4b | 35 | #include "target.h" |
13437d4b | 36 | #include "inferior.h" |
13437d4b | 37 | |
4b188b9f MK |
38 | #include "gdb_assert.h" |
39 | ||
13437d4b | 40 | #include "solist.h" |
bba93f6c | 41 | #include "solib.h" |
13437d4b KB |
42 | #include "solib-svr4.h" |
43 | ||
2f4950cd AC |
44 | #include "bfd-target.h" |
45 | #include "exec.h" | |
46 | ||
e5e2b9ff | 47 | static struct link_map_offsets *svr4_fetch_link_map_offsets (void); |
d5a921c9 | 48 | static int svr4_have_link_map_offsets (void); |
1c4dcb57 | 49 | |
4b188b9f MK |
50 | /* This hook is set to a function that provides native link map |
51 | offsets if the code in solib-legacy.c is linked in. */ | |
52 | struct link_map_offsets *(*legacy_svr4_fetch_link_map_offsets_hook) (void); | |
21479ded | 53 | |
13437d4b KB |
54 | /* Link map info to include in an allocated so_list entry */ |
55 | ||
56 | struct lm_info | |
57 | { | |
58 | /* Pointer to copy of link map from inferior. The type is char * | |
59 | rather than void *, so that we may use byte offsets to find the | |
60 | various fields without the need for a cast. */ | |
4066fc10 | 61 | gdb_byte *lm; |
13437d4b KB |
62 | }; |
63 | ||
64 | /* On SVR4 systems, a list of symbols in the dynamic linker where | |
65 | GDB can try to place a breakpoint to monitor shared library | |
66 | events. | |
67 | ||
68 | If none of these symbols are found, or other errors occur, then | |
69 | SVR4 systems will fall back to using a symbol as the "startup | |
70 | mapping complete" breakpoint address. */ | |
71 | ||
13437d4b KB |
72 | static char *solib_break_names[] = |
73 | { | |
74 | "r_debug_state", | |
75 | "_r_debug_state", | |
76 | "_dl_debug_state", | |
77 | "rtld_db_dlactivity", | |
1f72e589 | 78 | "_rtld_debug_state", |
4c0122c8 JB |
79 | |
80 | /* On the 64-bit PowerPC, the linker symbol with the same name as | |
81 | the C function points to a function descriptor, not to the entry | |
82 | point. The linker symbol whose name is the C function name | |
83 | prefixed with a '.' points to the function's entry point. So | |
84 | when we look through this table, we ignore symbols that point | |
85 | into the data section (thus skipping the descriptor's symbol), | |
86 | and eventually try this one, giving us the real entry point | |
87 | address. */ | |
88 | "._dl_debug_state", | |
89 | ||
13437d4b KB |
90 | NULL |
91 | }; | |
13437d4b KB |
92 | |
93 | #define BKPT_AT_SYMBOL 1 | |
94 | ||
ab31aa69 | 95 | #if defined (BKPT_AT_SYMBOL) |
13437d4b KB |
96 | static char *bkpt_names[] = |
97 | { | |
98 | #ifdef SOLIB_BKPT_NAME | |
99 | SOLIB_BKPT_NAME, /* Prefer configured name if it exists. */ | |
100 | #endif | |
101 | "_start", | |
ad3dcc5c | 102 | "__start", |
13437d4b KB |
103 | "main", |
104 | NULL | |
105 | }; | |
106 | #endif | |
107 | ||
13437d4b KB |
108 | static char *main_name_list[] = |
109 | { | |
110 | "main_$main", | |
111 | NULL | |
112 | }; | |
113 | ||
ae0167b9 AC |
114 | /* Macro to extract an address from a solib structure. When GDB is |
115 | configured for some 32-bit targets (e.g. Solaris 2.7 sparc), BFD is | |
116 | configured to handle 64-bit targets, so CORE_ADDR is 64 bits. We | |
117 | have to extract only the significant bits of addresses to get the | |
118 | right address when accessing the core file BFD. | |
119 | ||
120 | Assume that the address is unsigned. */ | |
13437d4b KB |
121 | |
122 | #define SOLIB_EXTRACT_ADDRESS(MEMBER) \ | |
ae0167b9 | 123 | extract_unsigned_integer (&(MEMBER), sizeof (MEMBER)) |
13437d4b KB |
124 | |
125 | /* local data declarations */ | |
126 | ||
13437d4b KB |
127 | /* link map access functions */ |
128 | ||
129 | static CORE_ADDR | |
130 | LM_ADDR (struct so_list *so) | |
131 | { | |
4b188b9f | 132 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
13437d4b | 133 | |
58bc91c9 MH |
134 | return (CORE_ADDR) extract_signed_integer (so->lm_info->lm + lmo->l_addr_offset, |
135 | lmo->l_addr_size); | |
13437d4b KB |
136 | } |
137 | ||
138 | static CORE_ADDR | |
139 | LM_NEXT (struct so_list *so) | |
140 | { | |
4b188b9f | 141 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
13437d4b | 142 | |
ae0167b9 AC |
143 | /* Assume that the address is unsigned. */ |
144 | return extract_unsigned_integer (so->lm_info->lm + lmo->l_next_offset, | |
145 | lmo->l_next_size); | |
13437d4b KB |
146 | } |
147 | ||
148 | static CORE_ADDR | |
149 | LM_NAME (struct so_list *so) | |
150 | { | |
4b188b9f | 151 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
13437d4b | 152 | |
ae0167b9 AC |
153 | /* Assume that the address is unsigned. */ |
154 | return extract_unsigned_integer (so->lm_info->lm + lmo->l_name_offset, | |
155 | lmo->l_name_size); | |
13437d4b KB |
156 | } |
157 | ||
13437d4b KB |
158 | static int |
159 | IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list *so) | |
160 | { | |
4b188b9f | 161 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
13437d4b | 162 | |
ae0167b9 AC |
163 | /* Assume that the address is unsigned. */ |
164 | return extract_unsigned_integer (so->lm_info->lm + lmo->l_prev_offset, | |
165 | lmo->l_prev_size) == 0; | |
13437d4b KB |
166 | } |
167 | ||
13437d4b KB |
168 | static CORE_ADDR debug_base; /* Base of dynamic linker structures */ |
169 | static CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */ | |
170 | ||
171 | /* Local function prototypes */ | |
172 | ||
173 | static int match_main (char *); | |
174 | ||
87f84c9d | 175 | static CORE_ADDR bfd_lookup_symbol (bfd *, char *, flagword); |
13437d4b KB |
176 | |
177 | /* | |
178 | ||
179 | LOCAL FUNCTION | |
180 | ||
181 | bfd_lookup_symbol -- lookup the value for a specific symbol | |
182 | ||
183 | SYNOPSIS | |
184 | ||
87f84c9d | 185 | CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname, flagword sect_flags) |
13437d4b KB |
186 | |
187 | DESCRIPTION | |
188 | ||
189 | An expensive way to lookup the value of a single symbol for | |
190 | bfd's that are only temporary anyway. This is used by the | |
191 | shared library support to find the address of the debugger | |
192 | interface structures in the shared library. | |
193 | ||
87f84c9d JB |
194 | If SECT_FLAGS is non-zero, only match symbols in sections whose |
195 | flags include all those in SECT_FLAGS. | |
196 | ||
13437d4b KB |
197 | Note that 0 is specifically allowed as an error return (no |
198 | such symbol). | |
199 | */ | |
200 | ||
201 | static CORE_ADDR | |
87f84c9d | 202 | bfd_lookup_symbol (bfd *abfd, char *symname, flagword sect_flags) |
13437d4b | 203 | { |
435b259c | 204 | long storage_needed; |
13437d4b KB |
205 | asymbol *sym; |
206 | asymbol **symbol_table; | |
207 | unsigned int number_of_symbols; | |
208 | unsigned int i; | |
209 | struct cleanup *back_to; | |
210 | CORE_ADDR symaddr = 0; | |
211 | ||
212 | storage_needed = bfd_get_symtab_upper_bound (abfd); | |
213 | ||
214 | if (storage_needed > 0) | |
215 | { | |
216 | symbol_table = (asymbol **) xmalloc (storage_needed); | |
4efb68b1 | 217 | back_to = make_cleanup (xfree, symbol_table); |
13437d4b KB |
218 | number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); |
219 | ||
220 | for (i = 0; i < number_of_symbols; i++) | |
221 | { | |
222 | sym = *symbol_table++; | |
6314a349 | 223 | if (strcmp (sym->name, symname) == 0 |
87f84c9d | 224 | && (sym->section->flags & sect_flags) == sect_flags) |
13437d4b KB |
225 | { |
226 | /* Bfd symbols are section relative. */ | |
227 | symaddr = sym->value + sym->section->vma; | |
228 | break; | |
229 | } | |
230 | } | |
231 | do_cleanups (back_to); | |
232 | } | |
233 | ||
234 | if (symaddr) | |
235 | return symaddr; | |
236 | ||
237 | /* On FreeBSD, the dynamic linker is stripped by default. So we'll | |
238 | have to check the dynamic string table too. */ | |
239 | ||
240 | storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd); | |
241 | ||
242 | if (storage_needed > 0) | |
243 | { | |
244 | symbol_table = (asymbol **) xmalloc (storage_needed); | |
4efb68b1 | 245 | back_to = make_cleanup (xfree, symbol_table); |
13437d4b KB |
246 | number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table); |
247 | ||
248 | for (i = 0; i < number_of_symbols; i++) | |
249 | { | |
250 | sym = *symbol_table++; | |
87f84c9d | 251 | |
6314a349 | 252 | if (strcmp (sym->name, symname) == 0 |
87f84c9d | 253 | && (sym->section->flags & sect_flags) == sect_flags) |
13437d4b KB |
254 | { |
255 | /* Bfd symbols are section relative. */ | |
256 | symaddr = sym->value + sym->section->vma; | |
257 | break; | |
258 | } | |
259 | } | |
260 | do_cleanups (back_to); | |
261 | } | |
262 | ||
263 | return symaddr; | |
264 | } | |
265 | ||
13437d4b KB |
266 | /* |
267 | ||
268 | LOCAL FUNCTION | |
269 | ||
270 | elf_locate_base -- locate the base address of dynamic linker structs | |
271 | for SVR4 elf targets. | |
272 | ||
273 | SYNOPSIS | |
274 | ||
275 | CORE_ADDR elf_locate_base (void) | |
276 | ||
277 | DESCRIPTION | |
278 | ||
279 | For SVR4 elf targets the address of the dynamic linker's runtime | |
280 | structure is contained within the dynamic info section in the | |
281 | executable file. The dynamic section is also mapped into the | |
282 | inferior address space. Because the runtime loader fills in the | |
283 | real address before starting the inferior, we have to read in the | |
284 | dynamic info section from the inferior address space. | |
285 | If there are any errors while trying to find the address, we | |
286 | silently return 0, otherwise the found address is returned. | |
287 | ||
288 | */ | |
289 | ||
290 | static CORE_ADDR | |
291 | elf_locate_base (void) | |
292 | { | |
7be0c536 | 293 | struct bfd_section *dyninfo_sect; |
13437d4b KB |
294 | int dyninfo_sect_size; |
295 | CORE_ADDR dyninfo_addr; | |
4066fc10 MI |
296 | gdb_byte *buf; |
297 | gdb_byte *bufend; | |
13437d4b KB |
298 | int arch_size; |
299 | ||
300 | /* Find the start address of the .dynamic section. */ | |
301 | dyninfo_sect = bfd_get_section_by_name (exec_bfd, ".dynamic"); | |
302 | if (dyninfo_sect == NULL) | |
303 | return 0; | |
304 | dyninfo_addr = bfd_section_vma (exec_bfd, dyninfo_sect); | |
305 | ||
306 | /* Read in .dynamic section, silently ignore errors. */ | |
307 | dyninfo_sect_size = bfd_section_size (exec_bfd, dyninfo_sect); | |
308 | buf = alloca (dyninfo_sect_size); | |
309 | if (target_read_memory (dyninfo_addr, buf, dyninfo_sect_size)) | |
310 | return 0; | |
311 | ||
312 | /* Find the DT_DEBUG entry in the the .dynamic section. | |
313 | For mips elf we look for DT_MIPS_RLD_MAP, mips elf apparently has | |
314 | no DT_DEBUG entries. */ | |
315 | ||
316 | arch_size = bfd_get_arch_size (exec_bfd); | |
317 | if (arch_size == -1) /* failure */ | |
318 | return 0; | |
319 | ||
320 | if (arch_size == 32) | |
321 | { /* 32-bit elf */ | |
322 | for (bufend = buf + dyninfo_sect_size; | |
323 | buf < bufend; | |
324 | buf += sizeof (Elf32_External_Dyn)) | |
325 | { | |
326 | Elf32_External_Dyn *x_dynp = (Elf32_External_Dyn *) buf; | |
327 | long dyn_tag; | |
328 | CORE_ADDR dyn_ptr; | |
329 | ||
330 | dyn_tag = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_tag); | |
331 | if (dyn_tag == DT_NULL) | |
332 | break; | |
333 | else if (dyn_tag == DT_DEBUG) | |
334 | { | |
335 | dyn_ptr = bfd_h_get_32 (exec_bfd, | |
336 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
337 | return dyn_ptr; | |
338 | } | |
13437d4b KB |
339 | else if (dyn_tag == DT_MIPS_RLD_MAP) |
340 | { | |
4066fc10 | 341 | gdb_byte *pbuf; |
743b930b | 342 | int pbuf_size = TARGET_PTR_BIT / HOST_CHAR_BIT; |
13437d4b | 343 | |
743b930b | 344 | pbuf = alloca (pbuf_size); |
13437d4b KB |
345 | /* DT_MIPS_RLD_MAP contains a pointer to the address |
346 | of the dynamic link structure. */ | |
347 | dyn_ptr = bfd_h_get_32 (exec_bfd, | |
348 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
743b930b | 349 | if (target_read_memory (dyn_ptr, pbuf, pbuf_size)) |
13437d4b | 350 | return 0; |
743b930b | 351 | return extract_unsigned_integer (pbuf, pbuf_size); |
13437d4b | 352 | } |
13437d4b KB |
353 | } |
354 | } | |
355 | else /* 64-bit elf */ | |
356 | { | |
357 | for (bufend = buf + dyninfo_sect_size; | |
358 | buf < bufend; | |
359 | buf += sizeof (Elf64_External_Dyn)) | |
360 | { | |
361 | Elf64_External_Dyn *x_dynp = (Elf64_External_Dyn *) buf; | |
362 | long dyn_tag; | |
363 | CORE_ADDR dyn_ptr; | |
364 | ||
365 | dyn_tag = bfd_h_get_64 (exec_bfd, (bfd_byte *) x_dynp->d_tag); | |
366 | if (dyn_tag == DT_NULL) | |
367 | break; | |
368 | else if (dyn_tag == DT_DEBUG) | |
369 | { | |
370 | dyn_ptr = bfd_h_get_64 (exec_bfd, | |
371 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
372 | return dyn_ptr; | |
373 | } | |
743b930b KB |
374 | else if (dyn_tag == DT_MIPS_RLD_MAP) |
375 | { | |
4066fc10 | 376 | gdb_byte *pbuf; |
743b930b KB |
377 | int pbuf_size = TARGET_PTR_BIT / HOST_CHAR_BIT; |
378 | ||
379 | pbuf = alloca (pbuf_size); | |
380 | /* DT_MIPS_RLD_MAP contains a pointer to the address | |
381 | of the dynamic link structure. */ | |
382 | dyn_ptr = bfd_h_get_64 (exec_bfd, | |
383 | (bfd_byte *) x_dynp->d_un.d_ptr); | |
384 | if (target_read_memory (dyn_ptr, pbuf, pbuf_size)) | |
385 | return 0; | |
386 | return extract_unsigned_integer (pbuf, pbuf_size); | |
387 | } | |
13437d4b KB |
388 | } |
389 | } | |
390 | ||
391 | /* DT_DEBUG entry not found. */ | |
392 | return 0; | |
393 | } | |
394 | ||
13437d4b KB |
395 | /* |
396 | ||
397 | LOCAL FUNCTION | |
398 | ||
399 | locate_base -- locate the base address of dynamic linker structs | |
400 | ||
401 | SYNOPSIS | |
402 | ||
403 | CORE_ADDR locate_base (void) | |
404 | ||
405 | DESCRIPTION | |
406 | ||
407 | For both the SunOS and SVR4 shared library implementations, if the | |
408 | inferior executable has been linked dynamically, there is a single | |
409 | address somewhere in the inferior's data space which is the key to | |
410 | locating all of the dynamic linker's runtime structures. This | |
411 | address is the value of the debug base symbol. The job of this | |
412 | function is to find and return that address, or to return 0 if there | |
413 | is no such address (the executable is statically linked for example). | |
414 | ||
415 | For SunOS, the job is almost trivial, since the dynamic linker and | |
416 | all of it's structures are statically linked to the executable at | |
417 | link time. Thus the symbol for the address we are looking for has | |
418 | already been added to the minimal symbol table for the executable's | |
419 | objfile at the time the symbol file's symbols were read, and all we | |
420 | have to do is look it up there. Note that we explicitly do NOT want | |
421 | to find the copies in the shared library. | |
422 | ||
423 | The SVR4 version is a bit more complicated because the address | |
424 | is contained somewhere in the dynamic info section. We have to go | |
425 | to a lot more work to discover the address of the debug base symbol. | |
426 | Because of this complexity, we cache the value we find and return that | |
427 | value on subsequent invocations. Note there is no copy in the | |
428 | executable symbol tables. | |
429 | ||
430 | */ | |
431 | ||
432 | static CORE_ADDR | |
433 | locate_base (void) | |
434 | { | |
13437d4b KB |
435 | /* Check to see if we have a currently valid address, and if so, avoid |
436 | doing all this work again and just return the cached address. If | |
437 | we have no cached address, try to locate it in the dynamic info | |
d5a921c9 KB |
438 | section for ELF executables. There's no point in doing any of this |
439 | though if we don't have some link map offsets to work with. */ | |
13437d4b | 440 | |
d5a921c9 | 441 | if (debug_base == 0 && svr4_have_link_map_offsets ()) |
13437d4b KB |
442 | { |
443 | if (exec_bfd != NULL | |
444 | && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) | |
445 | debug_base = elf_locate_base (); | |
13437d4b KB |
446 | } |
447 | return (debug_base); | |
13437d4b KB |
448 | } |
449 | ||
e4cd0d6a MK |
450 | /* Find the first element in the inferior's dynamic link map, and |
451 | return its address in the inferior. | |
13437d4b | 452 | |
e4cd0d6a MK |
453 | FIXME: Perhaps we should validate the info somehow, perhaps by |
454 | checking r_version for a known version number, or r_state for | |
455 | RT_CONSISTENT. */ | |
13437d4b KB |
456 | |
457 | static CORE_ADDR | |
e4cd0d6a | 458 | solib_svr4_r_map (void) |
13437d4b | 459 | { |
4b188b9f | 460 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
13437d4b | 461 | |
e4cd0d6a MK |
462 | return read_memory_typed_address (debug_base + lmo->r_map_offset, |
463 | builtin_type_void_data_ptr); | |
464 | } | |
13437d4b | 465 | |
e4cd0d6a MK |
466 | /* Find the link map for the dynamic linker (if it is not in the |
467 | normal list of loaded shared objects). */ | |
13437d4b | 468 | |
e4cd0d6a MK |
469 | static CORE_ADDR |
470 | solib_svr4_r_ldsomap (void) | |
471 | { | |
472 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); | |
473 | ULONGEST version; | |
13437d4b | 474 | |
e4cd0d6a MK |
475 | /* Check version, and return zero if `struct r_debug' doesn't have |
476 | the r_ldsomap member. */ | |
477 | version = read_memory_unsigned_integer (debug_base + lmo->r_version_offset, | |
478 | lmo->r_version_size); | |
479 | if (version < 2 || lmo->r_ldsomap_offset == -1) | |
480 | return 0; | |
13437d4b | 481 | |
e4cd0d6a MK |
482 | return read_memory_typed_address (debug_base + lmo->r_ldsomap_offset, |
483 | builtin_type_void_data_ptr); | |
13437d4b KB |
484 | } |
485 | ||
13437d4b KB |
486 | /* |
487 | ||
488 | LOCAL FUNCTION | |
489 | ||
490 | open_symbol_file_object | |
491 | ||
492 | SYNOPSIS | |
493 | ||
494 | void open_symbol_file_object (void *from_tty) | |
495 | ||
496 | DESCRIPTION | |
497 | ||
498 | If no open symbol file, attempt to locate and open the main symbol | |
499 | file. On SVR4 systems, this is the first link map entry. If its | |
500 | name is here, we can open it. Useful when attaching to a process | |
501 | without first loading its symbol file. | |
502 | ||
503 | If FROM_TTYP dereferences to a non-zero integer, allow messages to | |
504 | be printed. This parameter is a pointer rather than an int because | |
505 | open_symbol_file_object() is called via catch_errors() and | |
506 | catch_errors() requires a pointer argument. */ | |
507 | ||
508 | static int | |
509 | open_symbol_file_object (void *from_ttyp) | |
510 | { | |
511 | CORE_ADDR lm, l_name; | |
512 | char *filename; | |
513 | int errcode; | |
514 | int from_tty = *(int *)from_ttyp; | |
4b188b9f | 515 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
4066fc10 | 516 | gdb_byte *l_name_buf = xmalloc (lmo->l_name_size); |
b8c9b27d | 517 | struct cleanup *cleanups = make_cleanup (xfree, l_name_buf); |
13437d4b KB |
518 | |
519 | if (symfile_objfile) | |
520 | if (!query ("Attempt to reload symbols from process? ")) | |
521 | return 0; | |
522 | ||
523 | if ((debug_base = locate_base ()) == 0) | |
524 | return 0; /* failed somehow... */ | |
525 | ||
526 | /* First link map member should be the executable. */ | |
e4cd0d6a MK |
527 | lm = solib_svr4_r_map (); |
528 | if (lm == 0) | |
13437d4b KB |
529 | return 0; /* failed somehow... */ |
530 | ||
531 | /* Read address of name from target memory to GDB. */ | |
532 | read_memory (lm + lmo->l_name_offset, l_name_buf, lmo->l_name_size); | |
533 | ||
ae0167b9 AC |
534 | /* Convert the address to host format. Assume that the address is |
535 | unsigned. */ | |
536 | l_name = extract_unsigned_integer (l_name_buf, lmo->l_name_size); | |
13437d4b KB |
537 | |
538 | /* Free l_name_buf. */ | |
539 | do_cleanups (cleanups); | |
540 | ||
541 | if (l_name == 0) | |
542 | return 0; /* No filename. */ | |
543 | ||
544 | /* Now fetch the filename from target memory. */ | |
545 | target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode); | |
546 | ||
547 | if (errcode) | |
548 | { | |
8a3fe4f8 | 549 | warning (_("failed to read exec filename from attached file: %s"), |
13437d4b KB |
550 | safe_strerror (errcode)); |
551 | return 0; | |
552 | } | |
553 | ||
b8c9b27d | 554 | make_cleanup (xfree, filename); |
13437d4b | 555 | /* Have a pathname: read the symbol file. */ |
1adeb98a | 556 | symbol_file_add_main (filename, from_tty); |
13437d4b KB |
557 | |
558 | return 1; | |
559 | } | |
13437d4b KB |
560 | |
561 | /* LOCAL FUNCTION | |
562 | ||
563 | current_sos -- build a list of currently loaded shared objects | |
564 | ||
565 | SYNOPSIS | |
566 | ||
567 | struct so_list *current_sos () | |
568 | ||
569 | DESCRIPTION | |
570 | ||
571 | Build a list of `struct so_list' objects describing the shared | |
572 | objects currently loaded in the inferior. This list does not | |
573 | include an entry for the main executable file. | |
574 | ||
575 | Note that we only gather information directly available from the | |
576 | inferior --- we don't examine any of the shared library files | |
577 | themselves. The declaration of `struct so_list' says which fields | |
578 | we provide values for. */ | |
579 | ||
580 | static struct so_list * | |
581 | svr4_current_sos (void) | |
582 | { | |
583 | CORE_ADDR lm; | |
584 | struct so_list *head = 0; | |
585 | struct so_list **link_ptr = &head; | |
e4cd0d6a | 586 | CORE_ADDR ldsomap = 0; |
13437d4b KB |
587 | |
588 | /* Make sure we've looked up the inferior's dynamic linker's base | |
589 | structure. */ | |
590 | if (! debug_base) | |
591 | { | |
592 | debug_base = locate_base (); | |
593 | ||
594 | /* If we can't find the dynamic linker's base structure, this | |
595 | must not be a dynamically linked executable. Hmm. */ | |
596 | if (! debug_base) | |
597 | return 0; | |
598 | } | |
599 | ||
600 | /* Walk the inferior's link map list, and build our list of | |
601 | `struct so_list' nodes. */ | |
e4cd0d6a | 602 | lm = solib_svr4_r_map (); |
13437d4b KB |
603 | while (lm) |
604 | { | |
4b188b9f | 605 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
f4456994 | 606 | struct so_list *new = XZALLOC (struct so_list); |
b8c9b27d | 607 | struct cleanup *old_chain = make_cleanup (xfree, new); |
13437d4b | 608 | |
13437d4b | 609 | new->lm_info = xmalloc (sizeof (struct lm_info)); |
b8c9b27d | 610 | make_cleanup (xfree, new->lm_info); |
13437d4b | 611 | |
f4456994 | 612 | new->lm_info->lm = xzalloc (lmo->link_map_size); |
b8c9b27d | 613 | make_cleanup (xfree, new->lm_info->lm); |
13437d4b KB |
614 | |
615 | read_memory (lm, new->lm_info->lm, lmo->link_map_size); | |
616 | ||
617 | lm = LM_NEXT (new); | |
618 | ||
619 | /* For SVR4 versions, the first entry in the link map is for the | |
620 | inferior executable, so we must ignore it. For some versions of | |
621 | SVR4, it has no name. For others (Solaris 2.3 for example), it | |
622 | does have a name, so we can no longer use a missing name to | |
623 | decide when to ignore it. */ | |
e4cd0d6a | 624 | if (IGNORE_FIRST_LINK_MAP_ENTRY (new) && ldsomap == 0) |
13437d4b KB |
625 | free_so (new); |
626 | else | |
627 | { | |
628 | int errcode; | |
629 | char *buffer; | |
630 | ||
631 | /* Extract this shared object's name. */ | |
632 | target_read_string (LM_NAME (new), &buffer, | |
633 | SO_NAME_MAX_PATH_SIZE - 1, &errcode); | |
634 | if (errcode != 0) | |
8a3fe4f8 AC |
635 | warning (_("Can't read pathname for load map: %s."), |
636 | safe_strerror (errcode)); | |
13437d4b KB |
637 | else |
638 | { | |
639 | strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1); | |
640 | new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; | |
b8c9b27d | 641 | xfree (buffer); |
13437d4b KB |
642 | strcpy (new->so_original_name, new->so_name); |
643 | } | |
644 | ||
645 | /* If this entry has no name, or its name matches the name | |
646 | for the main executable, don't include it in the list. */ | |
647 | if (! new->so_name[0] | |
648 | || match_main (new->so_name)) | |
649 | free_so (new); | |
650 | else | |
651 | { | |
652 | new->next = 0; | |
653 | *link_ptr = new; | |
654 | link_ptr = &new->next; | |
655 | } | |
656 | } | |
657 | ||
e4cd0d6a MK |
658 | /* On Solaris, the dynamic linker is not in the normal list of |
659 | shared objects, so make sure we pick it up too. Having | |
660 | symbol information for the dynamic linker is quite crucial | |
661 | for skipping dynamic linker resolver code. */ | |
662 | if (lm == 0 && ldsomap == 0) | |
663 | lm = ldsomap = solib_svr4_r_ldsomap (); | |
664 | ||
13437d4b KB |
665 | discard_cleanups (old_chain); |
666 | } | |
667 | ||
668 | return head; | |
669 | } | |
670 | ||
bc4a16ae EZ |
671 | /* Get the address of the link_map for a given OBJFILE. Loop through |
672 | the link maps, and return the address of the one corresponding to | |
673 | the given objfile. Note that this function takes into account that | |
674 | objfile can be the main executable, not just a shared library. The | |
675 | main executable has always an empty name field in the linkmap. */ | |
676 | ||
677 | CORE_ADDR | |
678 | svr4_fetch_objfile_link_map (struct objfile *objfile) | |
679 | { | |
680 | CORE_ADDR lm; | |
681 | ||
682 | if ((debug_base = locate_base ()) == 0) | |
683 | return 0; /* failed somehow... */ | |
684 | ||
685 | /* Position ourselves on the first link map. */ | |
e4cd0d6a | 686 | lm = solib_svr4_r_map (); |
bc4a16ae EZ |
687 | while (lm) |
688 | { | |
689 | /* Get info on the layout of the r_debug and link_map structures. */ | |
4b188b9f | 690 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
bc4a16ae EZ |
691 | int errcode; |
692 | char *buffer; | |
693 | struct lm_info objfile_lm_info; | |
694 | struct cleanup *old_chain; | |
695 | CORE_ADDR name_address; | |
4066fc10 | 696 | gdb_byte *l_name_buf = xmalloc (lmo->l_name_size); |
bc4a16ae EZ |
697 | old_chain = make_cleanup (xfree, l_name_buf); |
698 | ||
699 | /* Set up the buffer to contain the portion of the link_map | |
700 | structure that gdb cares about. Note that this is not the | |
701 | whole link_map structure. */ | |
f4456994 | 702 | objfile_lm_info.lm = xzalloc (lmo->link_map_size); |
bc4a16ae | 703 | make_cleanup (xfree, objfile_lm_info.lm); |
bc4a16ae EZ |
704 | |
705 | /* Read the link map into our internal structure. */ | |
706 | read_memory (lm, objfile_lm_info.lm, lmo->link_map_size); | |
707 | ||
708 | /* Read address of name from target memory to GDB. */ | |
709 | read_memory (lm + lmo->l_name_offset, l_name_buf, lmo->l_name_size); | |
710 | ||
ae0167b9 AC |
711 | /* Extract this object's name. Assume that the address is |
712 | unsigned. */ | |
713 | name_address = extract_unsigned_integer (l_name_buf, lmo->l_name_size); | |
bc4a16ae EZ |
714 | target_read_string (name_address, &buffer, |
715 | SO_NAME_MAX_PATH_SIZE - 1, &errcode); | |
716 | make_cleanup (xfree, buffer); | |
717 | if (errcode != 0) | |
8a3fe4f8 AC |
718 | warning (_("Can't read pathname for load map: %s."), |
719 | safe_strerror (errcode)); | |
bc4a16ae EZ |
720 | else |
721 | { | |
722 | /* Is this the linkmap for the file we want? */ | |
723 | /* If the file is not a shared library and has no name, | |
724 | we are sure it is the main executable, so we return that. */ | |
725 | if ((buffer && strcmp (buffer, objfile->name) == 0) | |
726 | || (!(objfile->flags & OBJF_SHARED) && (strcmp (buffer, "") == 0))) | |
727 | { | |
728 | do_cleanups (old_chain); | |
729 | return lm; | |
730 | } | |
731 | } | |
ae0167b9 AC |
732 | /* Not the file we wanted, continue checking. Assume that the |
733 | address is unsigned. */ | |
734 | lm = extract_unsigned_integer (objfile_lm_info.lm + lmo->l_next_offset, | |
735 | lmo->l_next_size); | |
bc4a16ae EZ |
736 | do_cleanups (old_chain); |
737 | } | |
738 | return 0; | |
739 | } | |
13437d4b KB |
740 | |
741 | /* On some systems, the only way to recognize the link map entry for | |
742 | the main executable file is by looking at its name. Return | |
743 | non-zero iff SONAME matches one of the known main executable names. */ | |
744 | ||
745 | static int | |
746 | match_main (char *soname) | |
747 | { | |
748 | char **mainp; | |
749 | ||
750 | for (mainp = main_name_list; *mainp != NULL; mainp++) | |
751 | { | |
752 | if (strcmp (soname, *mainp) == 0) | |
753 | return (1); | |
754 | } | |
755 | ||
756 | return (0); | |
757 | } | |
758 | ||
13437d4b KB |
759 | /* Return 1 if PC lies in the dynamic symbol resolution code of the |
760 | SVR4 run time loader. */ | |
13437d4b KB |
761 | static CORE_ADDR interp_text_sect_low; |
762 | static CORE_ADDR interp_text_sect_high; | |
763 | static CORE_ADDR interp_plt_sect_low; | |
764 | static CORE_ADDR interp_plt_sect_high; | |
765 | ||
d7fa2ae2 KB |
766 | static int |
767 | svr4_in_dynsym_resolve_code (CORE_ADDR pc) | |
13437d4b KB |
768 | { |
769 | return ((pc >= interp_text_sect_low && pc < interp_text_sect_high) | |
770 | || (pc >= interp_plt_sect_low && pc < interp_plt_sect_high) | |
771 | || in_plt_section (pc, NULL)); | |
772 | } | |
13437d4b | 773 | |
2f4950cd AC |
774 | /* Given an executable's ABFD and target, compute the entry-point |
775 | address. */ | |
776 | ||
777 | static CORE_ADDR | |
778 | exec_entry_point (struct bfd *abfd, struct target_ops *targ) | |
779 | { | |
780 | /* KevinB wrote ... for most targets, the address returned by | |
781 | bfd_get_start_address() is the entry point for the start | |
782 | function. But, for some targets, bfd_get_start_address() returns | |
783 | the address of a function descriptor from which the entry point | |
784 | address may be extracted. This address is extracted by | |
785 | gdbarch_convert_from_func_ptr_addr(). The method | |
786 | gdbarch_convert_from_func_ptr_addr() is the merely the identify | |
787 | function for targets which don't use function descriptors. */ | |
788 | return gdbarch_convert_from_func_ptr_addr (current_gdbarch, | |
789 | bfd_get_start_address (abfd), | |
790 | targ); | |
791 | } | |
13437d4b KB |
792 | |
793 | /* | |
794 | ||
795 | LOCAL FUNCTION | |
796 | ||
797 | enable_break -- arrange for dynamic linker to hit breakpoint | |
798 | ||
799 | SYNOPSIS | |
800 | ||
801 | int enable_break (void) | |
802 | ||
803 | DESCRIPTION | |
804 | ||
805 | Both the SunOS and the SVR4 dynamic linkers have, as part of their | |
806 | debugger interface, support for arranging for the inferior to hit | |
807 | a breakpoint after mapping in the shared libraries. This function | |
808 | enables that breakpoint. | |
809 | ||
810 | For SunOS, there is a special flag location (in_debugger) which we | |
811 | set to 1. When the dynamic linker sees this flag set, it will set | |
812 | a breakpoint at a location known only to itself, after saving the | |
813 | original contents of that place and the breakpoint address itself, | |
814 | in it's own internal structures. When we resume the inferior, it | |
815 | will eventually take a SIGTRAP when it runs into the breakpoint. | |
816 | We handle this (in a different place) by restoring the contents of | |
817 | the breakpointed location (which is only known after it stops), | |
818 | chasing around to locate the shared libraries that have been | |
819 | loaded, then resuming. | |
820 | ||
821 | For SVR4, the debugger interface structure contains a member (r_brk) | |
822 | which is statically initialized at the time the shared library is | |
823 | built, to the offset of a function (_r_debug_state) which is guaran- | |
824 | teed to be called once before mapping in a library, and again when | |
825 | the mapping is complete. At the time we are examining this member, | |
826 | it contains only the unrelocated offset of the function, so we have | |
827 | to do our own relocation. Later, when the dynamic linker actually | |
828 | runs, it relocates r_brk to be the actual address of _r_debug_state(). | |
829 | ||
830 | The debugger interface structure also contains an enumeration which | |
831 | is set to either RT_ADD or RT_DELETE prior to changing the mapping, | |
832 | depending upon whether or not the library is being mapped or unmapped, | |
833 | and then set to RT_CONSISTENT after the library is mapped/unmapped. | |
834 | */ | |
835 | ||
836 | static int | |
837 | enable_break (void) | |
838 | { | |
839 | int success = 0; | |
840 | ||
13437d4b KB |
841 | #ifdef BKPT_AT_SYMBOL |
842 | ||
843 | struct minimal_symbol *msymbol; | |
844 | char **bkpt_namep; | |
845 | asection *interp_sect; | |
846 | ||
847 | /* First, remove all the solib event breakpoints. Their addresses | |
848 | may have changed since the last time we ran the program. */ | |
849 | remove_solib_event_breakpoints (); | |
850 | ||
13437d4b KB |
851 | interp_text_sect_low = interp_text_sect_high = 0; |
852 | interp_plt_sect_low = interp_plt_sect_high = 0; | |
853 | ||
854 | /* Find the .interp section; if not found, warn the user and drop | |
855 | into the old breakpoint at symbol code. */ | |
856 | interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); | |
857 | if (interp_sect) | |
858 | { | |
859 | unsigned int interp_sect_size; | |
860 | char *buf; | |
8ad2fcde KB |
861 | CORE_ADDR load_addr = 0; |
862 | int load_addr_found = 0; | |
f8766ec1 | 863 | struct so_list *so; |
e4f7b8c8 | 864 | bfd *tmp_bfd = NULL; |
2f4950cd | 865 | struct target_ops *tmp_bfd_target; |
e4f7b8c8 MS |
866 | int tmp_fd = -1; |
867 | char *tmp_pathname = NULL; | |
13437d4b KB |
868 | CORE_ADDR sym_addr = 0; |
869 | ||
870 | /* Read the contents of the .interp section into a local buffer; | |
871 | the contents specify the dynamic linker this program uses. */ | |
872 | interp_sect_size = bfd_section_size (exec_bfd, interp_sect); | |
873 | buf = alloca (interp_sect_size); | |
874 | bfd_get_section_contents (exec_bfd, interp_sect, | |
875 | buf, 0, interp_sect_size); | |
876 | ||
877 | /* Now we need to figure out where the dynamic linker was | |
878 | loaded so that we can load its symbols and place a breakpoint | |
879 | in the dynamic linker itself. | |
880 | ||
881 | This address is stored on the stack. However, I've been unable | |
882 | to find any magic formula to find it for Solaris (appears to | |
883 | be trivial on GNU/Linux). Therefore, we have to try an alternate | |
884 | mechanism to find the dynamic linker's base address. */ | |
e4f7b8c8 MS |
885 | |
886 | tmp_fd = solib_open (buf, &tmp_pathname); | |
887 | if (tmp_fd >= 0) | |
9f76c2cd | 888 | tmp_bfd = bfd_fopen (tmp_pathname, gnutarget, FOPEN_RB, tmp_fd); |
e4f7b8c8 | 889 | |
13437d4b KB |
890 | if (tmp_bfd == NULL) |
891 | goto bkpt_at_symbol; | |
892 | ||
893 | /* Make sure the dynamic linker's really a useful object. */ | |
894 | if (!bfd_check_format (tmp_bfd, bfd_object)) | |
895 | { | |
8a3fe4f8 | 896 | warning (_("Unable to grok dynamic linker %s as an object file"), buf); |
13437d4b KB |
897 | bfd_close (tmp_bfd); |
898 | goto bkpt_at_symbol; | |
899 | } | |
900 | ||
2f4950cd AC |
901 | /* Now convert the TMP_BFD into a target. That way target, as |
902 | well as BFD operations can be used. Note that closing the | |
903 | target will also close the underlying bfd. */ | |
904 | tmp_bfd_target = target_bfd_reopen (tmp_bfd); | |
905 | ||
f8766ec1 KB |
906 | /* On a running target, we can get the dynamic linker's base |
907 | address from the shared library table. */ | |
908 | solib_add (NULL, 0, NULL, auto_solib_add); | |
909 | so = master_so_list (); | |
910 | while (so) | |
8ad2fcde | 911 | { |
f8766ec1 | 912 | if (strcmp (buf, so->so_original_name) == 0) |
8ad2fcde KB |
913 | { |
914 | load_addr_found = 1; | |
f8766ec1 | 915 | load_addr = LM_ADDR (so); |
8ad2fcde KB |
916 | break; |
917 | } | |
f8766ec1 | 918 | so = so->next; |
8ad2fcde KB |
919 | } |
920 | ||
921 | /* Otherwise we find the dynamic linker's base address by examining | |
922 | the current pc (which should point at the entry point for the | |
923 | dynamic linker) and subtracting the offset of the entry point. */ | |
924 | if (!load_addr_found) | |
2f4950cd AC |
925 | load_addr = (read_pc () |
926 | - exec_entry_point (tmp_bfd, tmp_bfd_target)); | |
13437d4b KB |
927 | |
928 | /* Record the relocated start and end address of the dynamic linker | |
d7fa2ae2 | 929 | text and plt section for svr4_in_dynsym_resolve_code. */ |
13437d4b KB |
930 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
931 | if (interp_sect) | |
932 | { | |
933 | interp_text_sect_low = | |
934 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
935 | interp_text_sect_high = | |
936 | interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
937 | } | |
938 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); | |
939 | if (interp_sect) | |
940 | { | |
941 | interp_plt_sect_low = | |
942 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; | |
943 | interp_plt_sect_high = | |
944 | interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect); | |
945 | } | |
946 | ||
947 | /* Now try to set a breakpoint in the dynamic linker. */ | |
948 | for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) | |
949 | { | |
87f84c9d JB |
950 | /* On ABI's that use function descriptors, there are usually |
951 | two linker symbols associated with each C function: one | |
952 | pointing at the actual entry point of the machine code, | |
953 | and one pointing at the function's descriptor. The | |
954 | latter symbol has the same name as the C function. | |
955 | ||
956 | What we're looking for here is the machine code entry | |
957 | point, so we are only interested in symbols in code | |
958 | sections. */ | |
959 | sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep, SEC_CODE); | |
13437d4b KB |
960 | if (sym_addr != 0) |
961 | break; | |
962 | } | |
963 | ||
2f4950cd AC |
964 | /* We're done with both the temporary bfd and target. Remember, |
965 | closing the target closes the underlying bfd. */ | |
966 | target_close (tmp_bfd_target, 0); | |
13437d4b KB |
967 | |
968 | if (sym_addr != 0) | |
969 | { | |
970 | create_solib_event_breakpoint (load_addr + sym_addr); | |
971 | return 1; | |
972 | } | |
973 | ||
974 | /* For whatever reason we couldn't set a breakpoint in the dynamic | |
975 | linker. Warn and drop into the old code. */ | |
976 | bkpt_at_symbol: | |
8a3fe4f8 | 977 | warning (_("Unable to find dynamic linker breakpoint function.\nGDB will be unable to debug shared library initializers\nand track explicitly loaded dynamic code.")); |
13437d4b | 978 | } |
13437d4b KB |
979 | |
980 | /* Scan through the list of symbols, trying to look up the symbol and | |
981 | set a breakpoint there. Terminate loop when we/if we succeed. */ | |
982 | ||
983 | breakpoint_addr = 0; | |
984 | for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++) | |
985 | { | |
986 | msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); | |
987 | if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) | |
988 | { | |
989 | create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol)); | |
990 | return 1; | |
991 | } | |
992 | } | |
993 | ||
994 | /* Nothing good happened. */ | |
995 | success = 0; | |
996 | ||
997 | #endif /* BKPT_AT_SYMBOL */ | |
998 | ||
13437d4b KB |
999 | return (success); |
1000 | } | |
1001 | ||
1002 | /* | |
1003 | ||
1004 | LOCAL FUNCTION | |
1005 | ||
1006 | special_symbol_handling -- additional shared library symbol handling | |
1007 | ||
1008 | SYNOPSIS | |
1009 | ||
1010 | void special_symbol_handling () | |
1011 | ||
1012 | DESCRIPTION | |
1013 | ||
1014 | Once the symbols from a shared object have been loaded in the usual | |
1015 | way, we are called to do any system specific symbol handling that | |
1016 | is needed. | |
1017 | ||
ab31aa69 | 1018 | For SunOS4, this consisted of grunging around in the dynamic |
13437d4b KB |
1019 | linkers structures to find symbol definitions for "common" symbols |
1020 | and adding them to the minimal symbol table for the runtime common | |
1021 | objfile. | |
1022 | ||
ab31aa69 KB |
1023 | However, for SVR4, there's nothing to do. |
1024 | ||
13437d4b KB |
1025 | */ |
1026 | ||
1027 | static void | |
1028 | svr4_special_symbol_handling (void) | |
1029 | { | |
13437d4b KB |
1030 | } |
1031 | ||
e2a44558 KB |
1032 | /* Relocate the main executable. This function should be called upon |
1033 | stopping the inferior process at the entry point to the program. | |
1034 | The entry point from BFD is compared to the PC and if they are | |
1035 | different, the main executable is relocated by the proper amount. | |
1036 | ||
1037 | As written it will only attempt to relocate executables which | |
1038 | lack interpreter sections. It seems likely that only dynamic | |
1039 | linker executables will get relocated, though it should work | |
1040 | properly for a position-independent static executable as well. */ | |
1041 | ||
1042 | static void | |
1043 | svr4_relocate_main_executable (void) | |
1044 | { | |
1045 | asection *interp_sect; | |
1046 | CORE_ADDR pc = read_pc (); | |
1047 | ||
1048 | /* Decide if the objfile needs to be relocated. As indicated above, | |
1049 | we will only be here when execution is stopped at the beginning | |
1050 | of the program. Relocation is necessary if the address at which | |
1051 | we are presently stopped differs from the start address stored in | |
1052 | the executable AND there's no interpreter section. The condition | |
1053 | regarding the interpreter section is very important because if | |
1054 | there *is* an interpreter section, execution will begin there | |
1055 | instead. When there is an interpreter section, the start address | |
1056 | is (presumably) used by the interpreter at some point to start | |
1057 | execution of the program. | |
1058 | ||
1059 | If there is an interpreter, it is normal for it to be set to an | |
1060 | arbitrary address at the outset. The job of finding it is | |
1061 | handled in enable_break(). | |
1062 | ||
1063 | So, to summarize, relocations are necessary when there is no | |
1064 | interpreter section and the start address obtained from the | |
1065 | executable is different from the address at which GDB is | |
1066 | currently stopped. | |
1067 | ||
1068 | [ The astute reader will note that we also test to make sure that | |
1069 | the executable in question has the DYNAMIC flag set. It is my | |
1070 | opinion that this test is unnecessary (undesirable even). It | |
1071 | was added to avoid inadvertent relocation of an executable | |
1072 | whose e_type member in the ELF header is not ET_DYN. There may | |
1073 | be a time in the future when it is desirable to do relocations | |
1074 | on other types of files as well in which case this condition | |
1075 | should either be removed or modified to accomodate the new file | |
1076 | type. (E.g, an ET_EXEC executable which has been built to be | |
1077 | position-independent could safely be relocated by the OS if | |
1078 | desired. It is true that this violates the ABI, but the ABI | |
1079 | has been known to be bent from time to time.) - Kevin, Nov 2000. ] | |
1080 | */ | |
1081 | ||
1082 | interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); | |
1083 | if (interp_sect == NULL | |
1084 | && (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0 | |
2f4950cd | 1085 | && (exec_entry_point (exec_bfd, &exec_ops) != pc)) |
e2a44558 KB |
1086 | { |
1087 | struct cleanup *old_chain; | |
1088 | struct section_offsets *new_offsets; | |
1089 | int i, changed; | |
1090 | CORE_ADDR displacement; | |
1091 | ||
1092 | /* It is necessary to relocate the objfile. The amount to | |
1093 | relocate by is simply the address at which we are stopped | |
1094 | minus the starting address from the executable. | |
1095 | ||
1096 | We relocate all of the sections by the same amount. This | |
1097 | behavior is mandated by recent editions of the System V ABI. | |
1098 | According to the System V Application Binary Interface, | |
1099 | Edition 4.1, page 5-5: | |
1100 | ||
1101 | ... Though the system chooses virtual addresses for | |
1102 | individual processes, it maintains the segments' relative | |
1103 | positions. Because position-independent code uses relative | |
1104 | addressesing between segments, the difference between | |
1105 | virtual addresses in memory must match the difference | |
1106 | between virtual addresses in the file. The difference | |
1107 | between the virtual address of any segment in memory and | |
1108 | the corresponding virtual address in the file is thus a | |
1109 | single constant value for any one executable or shared | |
1110 | object in a given process. This difference is the base | |
1111 | address. One use of the base address is to relocate the | |
1112 | memory image of the program during dynamic linking. | |
1113 | ||
1114 | The same language also appears in Edition 4.0 of the System V | |
1115 | ABI and is left unspecified in some of the earlier editions. */ | |
1116 | ||
2f4950cd | 1117 | displacement = pc - exec_entry_point (exec_bfd, &exec_ops); |
e2a44558 KB |
1118 | changed = 0; |
1119 | ||
13fc0c2f KB |
1120 | new_offsets = xcalloc (symfile_objfile->num_sections, |
1121 | sizeof (struct section_offsets)); | |
b8c9b27d | 1122 | old_chain = make_cleanup (xfree, new_offsets); |
e2a44558 KB |
1123 | |
1124 | for (i = 0; i < symfile_objfile->num_sections; i++) | |
1125 | { | |
1126 | if (displacement != ANOFFSET (symfile_objfile->section_offsets, i)) | |
1127 | changed = 1; | |
1128 | new_offsets->offsets[i] = displacement; | |
1129 | } | |
1130 | ||
1131 | if (changed) | |
1132 | objfile_relocate (symfile_objfile, new_offsets); | |
1133 | ||
1134 | do_cleanups (old_chain); | |
1135 | } | |
1136 | } | |
1137 | ||
13437d4b KB |
1138 | /* |
1139 | ||
1140 | GLOBAL FUNCTION | |
1141 | ||
1142 | svr4_solib_create_inferior_hook -- shared library startup support | |
1143 | ||
1144 | SYNOPSIS | |
1145 | ||
7095b863 | 1146 | void svr4_solib_create_inferior_hook () |
13437d4b KB |
1147 | |
1148 | DESCRIPTION | |
1149 | ||
1150 | When gdb starts up the inferior, it nurses it along (through the | |
1151 | shell) until it is ready to execute it's first instruction. At this | |
1152 | point, this function gets called via expansion of the macro | |
1153 | SOLIB_CREATE_INFERIOR_HOOK. | |
1154 | ||
1155 | For SunOS executables, this first instruction is typically the | |
1156 | one at "_start", or a similar text label, regardless of whether | |
1157 | the executable is statically or dynamically linked. The runtime | |
1158 | startup code takes care of dynamically linking in any shared | |
1159 | libraries, once gdb allows the inferior to continue. | |
1160 | ||
1161 | For SVR4 executables, this first instruction is either the first | |
1162 | instruction in the dynamic linker (for dynamically linked | |
1163 | executables) or the instruction at "start" for statically linked | |
1164 | executables. For dynamically linked executables, the system | |
1165 | first exec's /lib/libc.so.N, which contains the dynamic linker, | |
1166 | and starts it running. The dynamic linker maps in any needed | |
1167 | shared libraries, maps in the actual user executable, and then | |
1168 | jumps to "start" in the user executable. | |
1169 | ||
1170 | For both SunOS shared libraries, and SVR4 shared libraries, we | |
1171 | can arrange to cooperate with the dynamic linker to discover the | |
1172 | names of shared libraries that are dynamically linked, and the | |
1173 | base addresses to which they are linked. | |
1174 | ||
1175 | This function is responsible for discovering those names and | |
1176 | addresses, and saving sufficient information about them to allow | |
1177 | their symbols to be read at a later time. | |
1178 | ||
1179 | FIXME | |
1180 | ||
1181 | Between enable_break() and disable_break(), this code does not | |
1182 | properly handle hitting breakpoints which the user might have | |
1183 | set in the startup code or in the dynamic linker itself. Proper | |
1184 | handling will probably have to wait until the implementation is | |
1185 | changed to use the "breakpoint handler function" method. | |
1186 | ||
1187 | Also, what if child has exit()ed? Must exit loop somehow. | |
1188 | */ | |
1189 | ||
e2a44558 | 1190 | static void |
13437d4b KB |
1191 | svr4_solib_create_inferior_hook (void) |
1192 | { | |
e2a44558 KB |
1193 | /* Relocate the main executable if necessary. */ |
1194 | svr4_relocate_main_executable (); | |
1195 | ||
d5a921c9 KB |
1196 | if (!svr4_have_link_map_offsets ()) |
1197 | { | |
8a3fe4f8 | 1198 | warning (_("no shared library support for this OS / ABI")); |
d5a921c9 KB |
1199 | return; |
1200 | ||
1201 | } | |
1202 | ||
13437d4b KB |
1203 | if (!enable_break ()) |
1204 | { | |
8a3fe4f8 | 1205 | warning (_("shared library handler failed to enable breakpoint")); |
13437d4b KB |
1206 | return; |
1207 | } | |
1208 | ||
ab31aa69 KB |
1209 | #if defined(_SCO_DS) |
1210 | /* SCO needs the loop below, other systems should be using the | |
13437d4b KB |
1211 | special shared library breakpoints and the shared library breakpoint |
1212 | service routine. | |
1213 | ||
1214 | Now run the target. It will eventually hit the breakpoint, at | |
1215 | which point all of the libraries will have been mapped in and we | |
1216 | can go groveling around in the dynamic linker structures to find | |
1217 | out what we need to know about them. */ | |
1218 | ||
1219 | clear_proceed_status (); | |
c0236d92 | 1220 | stop_soon = STOP_QUIETLY; |
13437d4b KB |
1221 | stop_signal = TARGET_SIGNAL_0; |
1222 | do | |
1223 | { | |
39f77062 | 1224 | target_resume (pid_to_ptid (-1), 0, stop_signal); |
13437d4b KB |
1225 | wait_for_inferior (); |
1226 | } | |
1227 | while (stop_signal != TARGET_SIGNAL_TRAP); | |
c0236d92 | 1228 | stop_soon = NO_STOP_QUIETLY; |
ab31aa69 | 1229 | #endif /* defined(_SCO_DS) */ |
13437d4b KB |
1230 | } |
1231 | ||
1232 | static void | |
1233 | svr4_clear_solib (void) | |
1234 | { | |
1235 | debug_base = 0; | |
1236 | } | |
1237 | ||
1238 | static void | |
1239 | svr4_free_so (struct so_list *so) | |
1240 | { | |
b8c9b27d KB |
1241 | xfree (so->lm_info->lm); |
1242 | xfree (so->lm_info); | |
13437d4b KB |
1243 | } |
1244 | ||
6bb7be43 JB |
1245 | |
1246 | /* Clear any bits of ADDR that wouldn't fit in a target-format | |
1247 | data pointer. "Data pointer" here refers to whatever sort of | |
1248 | address the dynamic linker uses to manage its sections. At the | |
1249 | moment, we don't support shared libraries on any processors where | |
1250 | code and data pointers are different sizes. | |
1251 | ||
1252 | This isn't really the right solution. What we really need here is | |
1253 | a way to do arithmetic on CORE_ADDR values that respects the | |
1254 | natural pointer/address correspondence. (For example, on the MIPS, | |
1255 | converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to | |
1256 | sign-extend the value. There, simply truncating the bits above | |
1257 | TARGET_PTR_BIT, as we do below, is no good.) This should probably | |
1258 | be a new gdbarch method or something. */ | |
1259 | static CORE_ADDR | |
1260 | svr4_truncate_ptr (CORE_ADDR addr) | |
1261 | { | |
1262 | if (TARGET_PTR_BIT == sizeof (CORE_ADDR) * 8) | |
1263 | /* We don't need to truncate anything, and the bit twiddling below | |
1264 | will fail due to overflow problems. */ | |
1265 | return addr; | |
1266 | else | |
1267 | return addr & (((CORE_ADDR) 1 << TARGET_PTR_BIT) - 1); | |
1268 | } | |
1269 | ||
1270 | ||
749499cb KB |
1271 | static void |
1272 | svr4_relocate_section_addresses (struct so_list *so, | |
1273 | struct section_table *sec) | |
1274 | { | |
6bb7be43 JB |
1275 | sec->addr = svr4_truncate_ptr (sec->addr + LM_ADDR (so)); |
1276 | sec->endaddr = svr4_truncate_ptr (sec->endaddr + LM_ADDR (so)); | |
749499cb | 1277 | } |
4b188b9f | 1278 | \f |
749499cb | 1279 | |
4b188b9f | 1280 | /* Architecture-specific operations. */ |
6bb7be43 | 1281 | |
4b188b9f MK |
1282 | /* Per-architecture data key. */ |
1283 | static struct gdbarch_data *solib_svr4_data; | |
e5e2b9ff | 1284 | |
4b188b9f | 1285 | struct solib_svr4_ops |
e5e2b9ff | 1286 | { |
4b188b9f MK |
1287 | /* Return a description of the layout of `struct link_map'. */ |
1288 | struct link_map_offsets *(*fetch_link_map_offsets)(void); | |
1289 | }; | |
e5e2b9ff | 1290 | |
4b188b9f | 1291 | /* Return a default for the architecture-specific operations. */ |
e5e2b9ff | 1292 | |
4b188b9f MK |
1293 | static void * |
1294 | solib_svr4_init (struct obstack *obstack) | |
e5e2b9ff | 1295 | { |
4b188b9f | 1296 | struct solib_svr4_ops *ops; |
e5e2b9ff | 1297 | |
4b188b9f MK |
1298 | ops = OBSTACK_ZALLOC (obstack, struct solib_svr4_ops); |
1299 | ops->fetch_link_map_offsets = legacy_svr4_fetch_link_map_offsets_hook; | |
1300 | return ops; | |
e5e2b9ff KB |
1301 | } |
1302 | ||
4b188b9f MK |
1303 | /* Set the architecture-specific `struct link_map_offsets' fetcher for |
1304 | GDBARCH to FLMO. */ | |
1c4dcb57 | 1305 | |
21479ded | 1306 | void |
e5e2b9ff KB |
1307 | set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch, |
1308 | struct link_map_offsets *(*flmo) (void)) | |
21479ded | 1309 | { |
4b188b9f MK |
1310 | struct solib_svr4_ops *ops = gdbarch_data (gdbarch, solib_svr4_data); |
1311 | ||
1312 | ops->fetch_link_map_offsets = flmo; | |
21479ded KB |
1313 | } |
1314 | ||
4b188b9f MK |
1315 | /* Fetch a link_map_offsets structure using the architecture-specific |
1316 | `struct link_map_offsets' fetcher. */ | |
1c4dcb57 | 1317 | |
4b188b9f MK |
1318 | static struct link_map_offsets * |
1319 | svr4_fetch_link_map_offsets (void) | |
21479ded | 1320 | { |
4b188b9f MK |
1321 | struct solib_svr4_ops *ops = gdbarch_data (current_gdbarch, solib_svr4_data); |
1322 | ||
1323 | gdb_assert (ops->fetch_link_map_offsets); | |
1324 | return ops->fetch_link_map_offsets (); | |
21479ded KB |
1325 | } |
1326 | ||
4b188b9f MK |
1327 | /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */ |
1328 | ||
1329 | static int | |
1330 | svr4_have_link_map_offsets (void) | |
1331 | { | |
1332 | struct solib_svr4_ops *ops = gdbarch_data (current_gdbarch, solib_svr4_data); | |
1333 | return (ops->fetch_link_map_offsets != NULL); | |
1334 | } | |
1335 | \f | |
1336 | ||
e4bbbda8 MK |
1337 | /* Most OS'es that have SVR4-style ELF dynamic libraries define a |
1338 | `struct r_debug' and a `struct link_map' that are binary compatible | |
1339 | with the origional SVR4 implementation. */ | |
1340 | ||
1341 | /* Fetch (and possibly build) an appropriate `struct link_map_offsets' | |
1342 | for an ILP32 SVR4 system. */ | |
1343 | ||
1344 | struct link_map_offsets * | |
1345 | svr4_ilp32_fetch_link_map_offsets (void) | |
1346 | { | |
1347 | static struct link_map_offsets lmo; | |
1348 | static struct link_map_offsets *lmp = NULL; | |
1349 | ||
1350 | if (lmp == NULL) | |
1351 | { | |
1352 | lmp = &lmo; | |
1353 | ||
e4cd0d6a MK |
1354 | lmo.r_version_offset = 0; |
1355 | lmo.r_version_size = 4; | |
e4bbbda8 | 1356 | lmo.r_map_offset = 4; |
e4cd0d6a | 1357 | lmo.r_ldsomap_offset = 20; |
e4bbbda8 MK |
1358 | |
1359 | /* Everything we need is in the first 20 bytes. */ | |
1360 | lmo.link_map_size = 20; | |
1361 | lmo.l_addr_offset = 0; | |
e4cd0d6a | 1362 | lmo.l_addr_size = 4; |
e4bbbda8 | 1363 | lmo.l_name_offset = 4; |
e4cd0d6a | 1364 | lmo.l_name_size = 4; |
e4bbbda8 | 1365 | lmo.l_next_offset = 12; |
e4cd0d6a | 1366 | lmo.l_next_size = 4; |
e4bbbda8 | 1367 | lmo.l_prev_offset = 16; |
e4cd0d6a | 1368 | lmo.l_prev_size = 4; |
e4bbbda8 MK |
1369 | } |
1370 | ||
1371 | return lmp; | |
1372 | } | |
1373 | ||
1374 | /* Fetch (and possibly build) an appropriate `struct link_map_offsets' | |
1375 | for an LP64 SVR4 system. */ | |
1376 | ||
1377 | struct link_map_offsets * | |
1378 | svr4_lp64_fetch_link_map_offsets (void) | |
1379 | { | |
1380 | static struct link_map_offsets lmo; | |
1381 | static struct link_map_offsets *lmp = NULL; | |
1382 | ||
1383 | if (lmp == NULL) | |
1384 | { | |
1385 | lmp = &lmo; | |
1386 | ||
e4cd0d6a MK |
1387 | lmo.r_version_offset = 0; |
1388 | lmo.r_version_size = 4; | |
e4bbbda8 | 1389 | lmo.r_map_offset = 8; |
e4cd0d6a | 1390 | lmo.r_ldsomap_offset = 40; |
e4bbbda8 MK |
1391 | |
1392 | /* Everything we need is in the first 40 bytes. */ | |
1393 | lmo.link_map_size = 40; | |
1394 | lmo.l_addr_offset = 0; | |
e4cd0d6a | 1395 | lmo.l_addr_size = 8; |
e4bbbda8 | 1396 | lmo.l_name_offset = 8; |
e4cd0d6a | 1397 | lmo.l_name_size = 8; |
e4bbbda8 | 1398 | lmo.l_next_offset = 24; |
e4cd0d6a | 1399 | lmo.l_next_size = 8; |
e4bbbda8 | 1400 | lmo.l_prev_offset = 32; |
e4cd0d6a | 1401 | lmo.l_prev_size = 8; |
e4bbbda8 MK |
1402 | } |
1403 | ||
1404 | return lmp; | |
1405 | } | |
1406 | \f | |
1407 | ||
13437d4b KB |
1408 | static struct target_so_ops svr4_so_ops; |
1409 | ||
a78f21af AC |
1410 | extern initialize_file_ftype _initialize_svr4_solib; /* -Wmissing-prototypes */ |
1411 | ||
13437d4b KB |
1412 | void |
1413 | _initialize_svr4_solib (void) | |
1414 | { | |
4b188b9f MK |
1415 | solib_svr4_data = gdbarch_data_register_pre_init (solib_svr4_init); |
1416 | ||
749499cb | 1417 | svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses; |
13437d4b KB |
1418 | svr4_so_ops.free_so = svr4_free_so; |
1419 | svr4_so_ops.clear_solib = svr4_clear_solib; | |
1420 | svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook; | |
1421 | svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling; | |
1422 | svr4_so_ops.current_sos = svr4_current_sos; | |
1423 | svr4_so_ops.open_symbol_file_object = open_symbol_file_object; | |
d7fa2ae2 | 1424 | svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code; |
13437d4b KB |
1425 | |
1426 | /* FIXME: Don't do this here. *_gdbarch_init() should set so_ops. */ | |
1427 | current_target_so_ops = &svr4_so_ops; | |
1428 | } |