| 1 | /* Handle SVR4 shared libraries for GDB, the GNU Debugger. |
| 2 | |
| 3 | Copyright (C) 1990-1996, 1998-2001, 2003-2012 Free Software |
| 4 | Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | |
| 23 | #include "elf/external.h" |
| 24 | #include "elf/common.h" |
| 25 | #include "elf/mips.h" |
| 26 | |
| 27 | #include "symtab.h" |
| 28 | #include "bfd.h" |
| 29 | #include "symfile.h" |
| 30 | #include "objfiles.h" |
| 31 | #include "gdbcore.h" |
| 32 | #include "target.h" |
| 33 | #include "inferior.h" |
| 34 | #include "regcache.h" |
| 35 | #include "gdbthread.h" |
| 36 | #include "observer.h" |
| 37 | |
| 38 | #include "gdb_assert.h" |
| 39 | |
| 40 | #include "solist.h" |
| 41 | #include "solib.h" |
| 42 | #include "solib-svr4.h" |
| 43 | |
| 44 | #include "bfd-target.h" |
| 45 | #include "elf-bfd.h" |
| 46 | #include "exec.h" |
| 47 | #include "auxv.h" |
| 48 | #include "exceptions.h" |
| 49 | |
| 50 | static struct link_map_offsets *svr4_fetch_link_map_offsets (void); |
| 51 | static int svr4_have_link_map_offsets (void); |
| 52 | static void svr4_relocate_main_executable (void); |
| 53 | |
| 54 | /* Link map info to include in an allocated so_list entry. */ |
| 55 | |
| 56 | struct lm_info |
| 57 | { |
| 58 | /* Amount by which addresses in the binary should be relocated to |
| 59 | match the inferior. The direct inferior value is L_ADDR_INFERIOR. |
| 60 | When prelinking is involved and the prelink base address changes, |
| 61 | we may need a different offset - the recomputed offset is in L_ADDR. |
| 62 | It is commonly the same value. It is cached as we want to warn about |
| 63 | the difference and compute it only once. L_ADDR is valid |
| 64 | iff L_ADDR_P. */ |
| 65 | CORE_ADDR l_addr, l_addr_inferior; |
| 66 | unsigned int l_addr_p : 1; |
| 67 | |
| 68 | /* The target location of lm. */ |
| 69 | CORE_ADDR lm_addr; |
| 70 | |
| 71 | /* Values read in from inferior's fields of the same name. */ |
| 72 | CORE_ADDR l_ld, l_next, l_prev, l_name; |
| 73 | }; |
| 74 | |
| 75 | /* On SVR4 systems, a list of symbols in the dynamic linker where |
| 76 | GDB can try to place a breakpoint to monitor shared library |
| 77 | events. |
| 78 | |
| 79 | If none of these symbols are found, or other errors occur, then |
| 80 | SVR4 systems will fall back to using a symbol as the "startup |
| 81 | mapping complete" breakpoint address. */ |
| 82 | |
| 83 | static const char * const solib_break_names[] = |
| 84 | { |
| 85 | "r_debug_state", |
| 86 | "_r_debug_state", |
| 87 | "_dl_debug_state", |
| 88 | "rtld_db_dlactivity", |
| 89 | "__dl_rtld_db_dlactivity", |
| 90 | "_rtld_debug_state", |
| 91 | |
| 92 | NULL |
| 93 | }; |
| 94 | |
| 95 | static const char * const bkpt_names[] = |
| 96 | { |
| 97 | "_start", |
| 98 | "__start", |
| 99 | "main", |
| 100 | NULL |
| 101 | }; |
| 102 | |
| 103 | static const char * const main_name_list[] = |
| 104 | { |
| 105 | "main_$main", |
| 106 | NULL |
| 107 | }; |
| 108 | |
| 109 | /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent |
| 110 | the same shared library. */ |
| 111 | |
| 112 | static int |
| 113 | svr4_same_1 (const char *gdb_so_name, const char *inferior_so_name) |
| 114 | { |
| 115 | if (strcmp (gdb_so_name, inferior_so_name) == 0) |
| 116 | return 1; |
| 117 | |
| 118 | /* On Solaris, when starting inferior we think that dynamic linker is |
| 119 | /usr/lib/ld.so.1, but later on, the table of loaded shared libraries |
| 120 | contains /lib/ld.so.1. Sometimes one file is a link to another, but |
| 121 | sometimes they have identical content, but are not linked to each |
| 122 | other. We don't restrict this check for Solaris, but the chances |
| 123 | of running into this situation elsewhere are very low. */ |
| 124 | if (strcmp (gdb_so_name, "/usr/lib/ld.so.1") == 0 |
| 125 | && strcmp (inferior_so_name, "/lib/ld.so.1") == 0) |
| 126 | return 1; |
| 127 | |
| 128 | /* Similarly, we observed the same issue with sparc64, but with |
| 129 | different locations. */ |
| 130 | if (strcmp (gdb_so_name, "/usr/lib/sparcv9/ld.so.1") == 0 |
| 131 | && strcmp (inferior_so_name, "/lib/sparcv9/ld.so.1") == 0) |
| 132 | return 1; |
| 133 | |
| 134 | return 0; |
| 135 | } |
| 136 | |
| 137 | static int |
| 138 | svr4_same (struct so_list *gdb, struct so_list *inferior) |
| 139 | { |
| 140 | return (svr4_same_1 (gdb->so_original_name, inferior->so_original_name)); |
| 141 | } |
| 142 | |
| 143 | static struct lm_info * |
| 144 | lm_info_read (CORE_ADDR lm_addr) |
| 145 | { |
| 146 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 147 | gdb_byte *lm; |
| 148 | struct lm_info *lm_info; |
| 149 | struct cleanup *back_to; |
| 150 | |
| 151 | lm = xmalloc (lmo->link_map_size); |
| 152 | back_to = make_cleanup (xfree, lm); |
| 153 | |
| 154 | if (target_read_memory (lm_addr, lm, lmo->link_map_size) != 0) |
| 155 | { |
| 156 | warning (_("Error reading shared library list entry at %s"), |
| 157 | paddress (target_gdbarch, lm_addr)), |
| 158 | lm_info = NULL; |
| 159 | } |
| 160 | else |
| 161 | { |
| 162 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
| 163 | |
| 164 | lm_info = xzalloc (sizeof (*lm_info)); |
| 165 | lm_info->lm_addr = lm_addr; |
| 166 | |
| 167 | lm_info->l_addr_inferior = extract_typed_address (&lm[lmo->l_addr_offset], |
| 168 | ptr_type); |
| 169 | lm_info->l_ld = extract_typed_address (&lm[lmo->l_ld_offset], ptr_type); |
| 170 | lm_info->l_next = extract_typed_address (&lm[lmo->l_next_offset], |
| 171 | ptr_type); |
| 172 | lm_info->l_prev = extract_typed_address (&lm[lmo->l_prev_offset], |
| 173 | ptr_type); |
| 174 | lm_info->l_name = extract_typed_address (&lm[lmo->l_name_offset], |
| 175 | ptr_type); |
| 176 | } |
| 177 | |
| 178 | do_cleanups (back_to); |
| 179 | |
| 180 | return lm_info; |
| 181 | } |
| 182 | |
| 183 | static int |
| 184 | has_lm_dynamic_from_link_map (void) |
| 185 | { |
| 186 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 187 | |
| 188 | return lmo->l_ld_offset >= 0; |
| 189 | } |
| 190 | |
| 191 | static CORE_ADDR |
| 192 | lm_addr_check (struct so_list *so, bfd *abfd) |
| 193 | { |
| 194 | if (!so->lm_info->l_addr_p) |
| 195 | { |
| 196 | struct bfd_section *dyninfo_sect; |
| 197 | CORE_ADDR l_addr, l_dynaddr, dynaddr; |
| 198 | |
| 199 | l_addr = so->lm_info->l_addr_inferior; |
| 200 | |
| 201 | if (! abfd || ! has_lm_dynamic_from_link_map ()) |
| 202 | goto set_addr; |
| 203 | |
| 204 | l_dynaddr = so->lm_info->l_ld; |
| 205 | |
| 206 | dyninfo_sect = bfd_get_section_by_name (abfd, ".dynamic"); |
| 207 | if (dyninfo_sect == NULL) |
| 208 | goto set_addr; |
| 209 | |
| 210 | dynaddr = bfd_section_vma (abfd, dyninfo_sect); |
| 211 | |
| 212 | if (dynaddr + l_addr != l_dynaddr) |
| 213 | { |
| 214 | CORE_ADDR align = 0x1000; |
| 215 | CORE_ADDR minpagesize = align; |
| 216 | |
| 217 | if (bfd_get_flavour (abfd) == bfd_target_elf_flavour) |
| 218 | { |
| 219 | Elf_Internal_Ehdr *ehdr = elf_tdata (abfd)->elf_header; |
| 220 | Elf_Internal_Phdr *phdr = elf_tdata (abfd)->phdr; |
| 221 | int i; |
| 222 | |
| 223 | align = 1; |
| 224 | |
| 225 | for (i = 0; i < ehdr->e_phnum; i++) |
| 226 | if (phdr[i].p_type == PT_LOAD && phdr[i].p_align > align) |
| 227 | align = phdr[i].p_align; |
| 228 | |
| 229 | minpagesize = get_elf_backend_data (abfd)->minpagesize; |
| 230 | } |
| 231 | |
| 232 | /* Turn it into a mask. */ |
| 233 | align--; |
| 234 | |
| 235 | /* If the changes match the alignment requirements, we |
| 236 | assume we're using a core file that was generated by the |
| 237 | same binary, just prelinked with a different base offset. |
| 238 | If it doesn't match, we may have a different binary, the |
| 239 | same binary with the dynamic table loaded at an unrelated |
| 240 | location, or anything, really. To avoid regressions, |
| 241 | don't adjust the base offset in the latter case, although |
| 242 | odds are that, if things really changed, debugging won't |
| 243 | quite work. |
| 244 | |
| 245 | One could expect more the condition |
| 246 | ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0) |
| 247 | but the one below is relaxed for PPC. The PPC kernel supports |
| 248 | either 4k or 64k page sizes. To be prepared for 64k pages, |
| 249 | PPC ELF files are built using an alignment requirement of 64k. |
| 250 | However, when running on a kernel supporting 4k pages, the memory |
| 251 | mapping of the library may not actually happen on a 64k boundary! |
| 252 | |
| 253 | (In the usual case where (l_addr & align) == 0, this check is |
| 254 | equivalent to the possibly expected check above.) |
| 255 | |
| 256 | Even on PPC it must be zero-aligned at least for MINPAGESIZE. */ |
| 257 | |
| 258 | l_addr = l_dynaddr - dynaddr; |
| 259 | |
| 260 | if ((l_addr & (minpagesize - 1)) == 0 |
| 261 | && (l_addr & align) == ((l_dynaddr - dynaddr) & align)) |
| 262 | { |
| 263 | if (info_verbose) |
| 264 | printf_unfiltered (_("Using PIC (Position Independent Code) " |
| 265 | "prelink displacement %s for \"%s\".\n"), |
| 266 | paddress (target_gdbarch, l_addr), |
| 267 | so->so_name); |
| 268 | } |
| 269 | else |
| 270 | { |
| 271 | /* There is no way to verify the library file matches. prelink |
| 272 | can during prelinking of an unprelinked file (or unprelinking |
| 273 | of a prelinked file) shift the DYNAMIC segment by arbitrary |
| 274 | offset without any page size alignment. There is no way to |
| 275 | find out the ELF header and/or Program Headers for a limited |
| 276 | verification if it they match. One could do a verification |
| 277 | of the DYNAMIC segment. Still the found address is the best |
| 278 | one GDB could find. */ |
| 279 | |
| 280 | warning (_(".dynamic section for \"%s\" " |
| 281 | "is not at the expected address " |
| 282 | "(wrong library or version mismatch?)"), so->so_name); |
| 283 | } |
| 284 | } |
| 285 | |
| 286 | set_addr: |
| 287 | so->lm_info->l_addr = l_addr; |
| 288 | so->lm_info->l_addr_p = 1; |
| 289 | } |
| 290 | |
| 291 | return so->lm_info->l_addr; |
| 292 | } |
| 293 | |
| 294 | /* Per pspace SVR4 specific data. */ |
| 295 | |
| 296 | struct svr4_info |
| 297 | { |
| 298 | CORE_ADDR debug_base; /* Base of dynamic linker structures. */ |
| 299 | |
| 300 | /* Validity flag for debug_loader_offset. */ |
| 301 | int debug_loader_offset_p; |
| 302 | |
| 303 | /* Load address for the dynamic linker, inferred. */ |
| 304 | CORE_ADDR debug_loader_offset; |
| 305 | |
| 306 | /* Name of the dynamic linker, valid if debug_loader_offset_p. */ |
| 307 | char *debug_loader_name; |
| 308 | |
| 309 | /* Load map address for the main executable. */ |
| 310 | CORE_ADDR main_lm_addr; |
| 311 | |
| 312 | CORE_ADDR interp_text_sect_low; |
| 313 | CORE_ADDR interp_text_sect_high; |
| 314 | CORE_ADDR interp_plt_sect_low; |
| 315 | CORE_ADDR interp_plt_sect_high; |
| 316 | }; |
| 317 | |
| 318 | /* Per-program-space data key. */ |
| 319 | static const struct program_space_data *solib_svr4_pspace_data; |
| 320 | |
| 321 | static void |
| 322 | svr4_pspace_data_cleanup (struct program_space *pspace, void *arg) |
| 323 | { |
| 324 | struct svr4_info *info; |
| 325 | |
| 326 | info = program_space_data (pspace, solib_svr4_pspace_data); |
| 327 | xfree (info); |
| 328 | } |
| 329 | |
| 330 | /* Get the current svr4 data. If none is found yet, add it now. This |
| 331 | function always returns a valid object. */ |
| 332 | |
| 333 | static struct svr4_info * |
| 334 | get_svr4_info (void) |
| 335 | { |
| 336 | struct svr4_info *info; |
| 337 | |
| 338 | info = program_space_data (current_program_space, solib_svr4_pspace_data); |
| 339 | if (info != NULL) |
| 340 | return info; |
| 341 | |
| 342 | info = XZALLOC (struct svr4_info); |
| 343 | set_program_space_data (current_program_space, solib_svr4_pspace_data, info); |
| 344 | return info; |
| 345 | } |
| 346 | |
| 347 | /* Local function prototypes */ |
| 348 | |
| 349 | static int match_main (const char *); |
| 350 | |
| 351 | /* Read program header TYPE from inferior memory. The header is found |
| 352 | by scanning the OS auxillary vector. |
| 353 | |
| 354 | If TYPE == -1, return the program headers instead of the contents of |
| 355 | one program header. |
| 356 | |
| 357 | Return a pointer to allocated memory holding the program header contents, |
| 358 | or NULL on failure. If sucessful, and unless P_SECT_SIZE is NULL, the |
| 359 | size of those contents is returned to P_SECT_SIZE. Likewise, the target |
| 360 | architecture size (32-bit or 64-bit) is returned to P_ARCH_SIZE. */ |
| 361 | |
| 362 | static gdb_byte * |
| 363 | read_program_header (int type, int *p_sect_size, int *p_arch_size) |
| 364 | { |
| 365 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); |
| 366 | CORE_ADDR at_phdr, at_phent, at_phnum, pt_phdr = 0; |
| 367 | int arch_size, sect_size; |
| 368 | CORE_ADDR sect_addr; |
| 369 | gdb_byte *buf; |
| 370 | int pt_phdr_p = 0; |
| 371 | |
| 372 | /* Get required auxv elements from target. */ |
| 373 | if (target_auxv_search (¤t_target, AT_PHDR, &at_phdr) <= 0) |
| 374 | return 0; |
| 375 | if (target_auxv_search (¤t_target, AT_PHENT, &at_phent) <= 0) |
| 376 | return 0; |
| 377 | if (target_auxv_search (¤t_target, AT_PHNUM, &at_phnum) <= 0) |
| 378 | return 0; |
| 379 | if (!at_phdr || !at_phnum) |
| 380 | return 0; |
| 381 | |
| 382 | /* Determine ELF architecture type. */ |
| 383 | if (at_phent == sizeof (Elf32_External_Phdr)) |
| 384 | arch_size = 32; |
| 385 | else if (at_phent == sizeof (Elf64_External_Phdr)) |
| 386 | arch_size = 64; |
| 387 | else |
| 388 | return 0; |
| 389 | |
| 390 | /* Find the requested segment. */ |
| 391 | if (type == -1) |
| 392 | { |
| 393 | sect_addr = at_phdr; |
| 394 | sect_size = at_phent * at_phnum; |
| 395 | } |
| 396 | else if (arch_size == 32) |
| 397 | { |
| 398 | Elf32_External_Phdr phdr; |
| 399 | int i; |
| 400 | |
| 401 | /* Search for requested PHDR. */ |
| 402 | for (i = 0; i < at_phnum; i++) |
| 403 | { |
| 404 | int p_type; |
| 405 | |
| 406 | if (target_read_memory (at_phdr + i * sizeof (phdr), |
| 407 | (gdb_byte *)&phdr, sizeof (phdr))) |
| 408 | return 0; |
| 409 | |
| 410 | p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type, |
| 411 | 4, byte_order); |
| 412 | |
| 413 | if (p_type == PT_PHDR) |
| 414 | { |
| 415 | pt_phdr_p = 1; |
| 416 | pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr, |
| 417 | 4, byte_order); |
| 418 | } |
| 419 | |
| 420 | if (p_type == type) |
| 421 | break; |
| 422 | } |
| 423 | |
| 424 | if (i == at_phnum) |
| 425 | return 0; |
| 426 | |
| 427 | /* Retrieve address and size. */ |
| 428 | sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr, |
| 429 | 4, byte_order); |
| 430 | sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz, |
| 431 | 4, byte_order); |
| 432 | } |
| 433 | else |
| 434 | { |
| 435 | Elf64_External_Phdr phdr; |
| 436 | int i; |
| 437 | |
| 438 | /* Search for requested PHDR. */ |
| 439 | for (i = 0; i < at_phnum; i++) |
| 440 | { |
| 441 | int p_type; |
| 442 | |
| 443 | if (target_read_memory (at_phdr + i * sizeof (phdr), |
| 444 | (gdb_byte *)&phdr, sizeof (phdr))) |
| 445 | return 0; |
| 446 | |
| 447 | p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type, |
| 448 | 4, byte_order); |
| 449 | |
| 450 | if (p_type == PT_PHDR) |
| 451 | { |
| 452 | pt_phdr_p = 1; |
| 453 | pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr, |
| 454 | 8, byte_order); |
| 455 | } |
| 456 | |
| 457 | if (p_type == type) |
| 458 | break; |
| 459 | } |
| 460 | |
| 461 | if (i == at_phnum) |
| 462 | return 0; |
| 463 | |
| 464 | /* Retrieve address and size. */ |
| 465 | sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr, |
| 466 | 8, byte_order); |
| 467 | sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz, |
| 468 | 8, byte_order); |
| 469 | } |
| 470 | |
| 471 | /* PT_PHDR is optional, but we really need it |
| 472 | for PIE to make this work in general. */ |
| 473 | |
| 474 | if (pt_phdr_p) |
| 475 | { |
| 476 | /* at_phdr is real address in memory. pt_phdr is what pheader says it is. |
| 477 | Relocation offset is the difference between the two. */ |
| 478 | sect_addr = sect_addr + (at_phdr - pt_phdr); |
| 479 | } |
| 480 | |
| 481 | /* Read in requested program header. */ |
| 482 | buf = xmalloc (sect_size); |
| 483 | if (target_read_memory (sect_addr, buf, sect_size)) |
| 484 | { |
| 485 | xfree (buf); |
| 486 | return NULL; |
| 487 | } |
| 488 | |
| 489 | if (p_arch_size) |
| 490 | *p_arch_size = arch_size; |
| 491 | if (p_sect_size) |
| 492 | *p_sect_size = sect_size; |
| 493 | |
| 494 | return buf; |
| 495 | } |
| 496 | |
| 497 | |
| 498 | /* Return program interpreter string. */ |
| 499 | static gdb_byte * |
| 500 | find_program_interpreter (void) |
| 501 | { |
| 502 | gdb_byte *buf = NULL; |
| 503 | |
| 504 | /* If we have an exec_bfd, use its section table. */ |
| 505 | if (exec_bfd |
| 506 | && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) |
| 507 | { |
| 508 | struct bfd_section *interp_sect; |
| 509 | |
| 510 | interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); |
| 511 | if (interp_sect != NULL) |
| 512 | { |
| 513 | int sect_size = bfd_section_size (exec_bfd, interp_sect); |
| 514 | |
| 515 | buf = xmalloc (sect_size); |
| 516 | bfd_get_section_contents (exec_bfd, interp_sect, buf, 0, sect_size); |
| 517 | } |
| 518 | } |
| 519 | |
| 520 | /* If we didn't find it, use the target auxillary vector. */ |
| 521 | if (!buf) |
| 522 | buf = read_program_header (PT_INTERP, NULL, NULL); |
| 523 | |
| 524 | return buf; |
| 525 | } |
| 526 | |
| 527 | |
| 528 | /* Scan for DYNTAG in .dynamic section of ABFD. If DYNTAG is found 1 is |
| 529 | returned and the corresponding PTR is set. */ |
| 530 | |
| 531 | static int |
| 532 | scan_dyntag (int dyntag, bfd *abfd, CORE_ADDR *ptr) |
| 533 | { |
| 534 | int arch_size, step, sect_size; |
| 535 | long dyn_tag; |
| 536 | CORE_ADDR dyn_ptr, dyn_addr; |
| 537 | gdb_byte *bufend, *bufstart, *buf; |
| 538 | Elf32_External_Dyn *x_dynp_32; |
| 539 | Elf64_External_Dyn *x_dynp_64; |
| 540 | struct bfd_section *sect; |
| 541 | struct target_section *target_section; |
| 542 | |
| 543 | if (abfd == NULL) |
| 544 | return 0; |
| 545 | |
| 546 | if (bfd_get_flavour (abfd) != bfd_target_elf_flavour) |
| 547 | return 0; |
| 548 | |
| 549 | arch_size = bfd_get_arch_size (abfd); |
| 550 | if (arch_size == -1) |
| 551 | return 0; |
| 552 | |
| 553 | /* Find the start address of the .dynamic section. */ |
| 554 | sect = bfd_get_section_by_name (abfd, ".dynamic"); |
| 555 | if (sect == NULL) |
| 556 | return 0; |
| 557 | |
| 558 | for (target_section = current_target_sections->sections; |
| 559 | target_section < current_target_sections->sections_end; |
| 560 | target_section++) |
| 561 | if (sect == target_section->the_bfd_section) |
| 562 | break; |
| 563 | if (target_section < current_target_sections->sections_end) |
| 564 | dyn_addr = target_section->addr; |
| 565 | else |
| 566 | { |
| 567 | /* ABFD may come from OBJFILE acting only as a symbol file without being |
| 568 | loaded into the target (see add_symbol_file_command). This case is |
| 569 | such fallback to the file VMA address without the possibility of |
| 570 | having the section relocated to its actual in-memory address. */ |
| 571 | |
| 572 | dyn_addr = bfd_section_vma (abfd, sect); |
| 573 | } |
| 574 | |
| 575 | /* Read in .dynamic from the BFD. We will get the actual value |
| 576 | from memory later. */ |
| 577 | sect_size = bfd_section_size (abfd, sect); |
| 578 | buf = bufstart = alloca (sect_size); |
| 579 | if (!bfd_get_section_contents (abfd, sect, |
| 580 | buf, 0, sect_size)) |
| 581 | return 0; |
| 582 | |
| 583 | /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */ |
| 584 | step = (arch_size == 32) ? sizeof (Elf32_External_Dyn) |
| 585 | : sizeof (Elf64_External_Dyn); |
| 586 | for (bufend = buf + sect_size; |
| 587 | buf < bufend; |
| 588 | buf += step) |
| 589 | { |
| 590 | if (arch_size == 32) |
| 591 | { |
| 592 | x_dynp_32 = (Elf32_External_Dyn *) buf; |
| 593 | dyn_tag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_tag); |
| 594 | dyn_ptr = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_un.d_ptr); |
| 595 | } |
| 596 | else |
| 597 | { |
| 598 | x_dynp_64 = (Elf64_External_Dyn *) buf; |
| 599 | dyn_tag = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_tag); |
| 600 | dyn_ptr = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_un.d_ptr); |
| 601 | } |
| 602 | if (dyn_tag == DT_NULL) |
| 603 | return 0; |
| 604 | if (dyn_tag == dyntag) |
| 605 | { |
| 606 | /* If requested, try to read the runtime value of this .dynamic |
| 607 | entry. */ |
| 608 | if (ptr) |
| 609 | { |
| 610 | struct type *ptr_type; |
| 611 | gdb_byte ptr_buf[8]; |
| 612 | CORE_ADDR ptr_addr; |
| 613 | |
| 614 | ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
| 615 | ptr_addr = dyn_addr + (buf - bufstart) + arch_size / 8; |
| 616 | if (target_read_memory (ptr_addr, ptr_buf, arch_size / 8) == 0) |
| 617 | dyn_ptr = extract_typed_address (ptr_buf, ptr_type); |
| 618 | *ptr = dyn_ptr; |
| 619 | } |
| 620 | return 1; |
| 621 | } |
| 622 | } |
| 623 | |
| 624 | return 0; |
| 625 | } |
| 626 | |
| 627 | /* Scan for DYNTAG in .dynamic section of the target's main executable, |
| 628 | found by consulting the OS auxillary vector. If DYNTAG is found 1 is |
| 629 | returned and the corresponding PTR is set. */ |
| 630 | |
| 631 | static int |
| 632 | scan_dyntag_auxv (int dyntag, CORE_ADDR *ptr) |
| 633 | { |
| 634 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); |
| 635 | int sect_size, arch_size, step; |
| 636 | long dyn_tag; |
| 637 | CORE_ADDR dyn_ptr; |
| 638 | gdb_byte *bufend, *bufstart, *buf; |
| 639 | |
| 640 | /* Read in .dynamic section. */ |
| 641 | buf = bufstart = read_program_header (PT_DYNAMIC, §_size, &arch_size); |
| 642 | if (!buf) |
| 643 | return 0; |
| 644 | |
| 645 | /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */ |
| 646 | step = (arch_size == 32) ? sizeof (Elf32_External_Dyn) |
| 647 | : sizeof (Elf64_External_Dyn); |
| 648 | for (bufend = buf + sect_size; |
| 649 | buf < bufend; |
| 650 | buf += step) |
| 651 | { |
| 652 | if (arch_size == 32) |
| 653 | { |
| 654 | Elf32_External_Dyn *dynp = (Elf32_External_Dyn *) buf; |
| 655 | |
| 656 | dyn_tag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag, |
| 657 | 4, byte_order); |
| 658 | dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr, |
| 659 | 4, byte_order); |
| 660 | } |
| 661 | else |
| 662 | { |
| 663 | Elf64_External_Dyn *dynp = (Elf64_External_Dyn *) buf; |
| 664 | |
| 665 | dyn_tag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag, |
| 666 | 8, byte_order); |
| 667 | dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr, |
| 668 | 8, byte_order); |
| 669 | } |
| 670 | if (dyn_tag == DT_NULL) |
| 671 | break; |
| 672 | |
| 673 | if (dyn_tag == dyntag) |
| 674 | { |
| 675 | if (ptr) |
| 676 | *ptr = dyn_ptr; |
| 677 | |
| 678 | xfree (bufstart); |
| 679 | return 1; |
| 680 | } |
| 681 | } |
| 682 | |
| 683 | xfree (bufstart); |
| 684 | return 0; |
| 685 | } |
| 686 | |
| 687 | /* Locate the base address of dynamic linker structs for SVR4 elf |
| 688 | targets. |
| 689 | |
| 690 | For SVR4 elf targets the address of the dynamic linker's runtime |
| 691 | structure is contained within the dynamic info section in the |
| 692 | executable file. The dynamic section is also mapped into the |
| 693 | inferior address space. Because the runtime loader fills in the |
| 694 | real address before starting the inferior, we have to read in the |
| 695 | dynamic info section from the inferior address space. |
| 696 | If there are any errors while trying to find the address, we |
| 697 | silently return 0, otherwise the found address is returned. */ |
| 698 | |
| 699 | static CORE_ADDR |
| 700 | elf_locate_base (void) |
| 701 | { |
| 702 | struct minimal_symbol *msymbol; |
| 703 | CORE_ADDR dyn_ptr; |
| 704 | |
| 705 | /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this |
| 706 | instead of DT_DEBUG, although they sometimes contain an unused |
| 707 | DT_DEBUG. */ |
| 708 | if (scan_dyntag (DT_MIPS_RLD_MAP, exec_bfd, &dyn_ptr) |
| 709 | || scan_dyntag_auxv (DT_MIPS_RLD_MAP, &dyn_ptr)) |
| 710 | { |
| 711 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
| 712 | gdb_byte *pbuf; |
| 713 | int pbuf_size = TYPE_LENGTH (ptr_type); |
| 714 | |
| 715 | pbuf = alloca (pbuf_size); |
| 716 | /* DT_MIPS_RLD_MAP contains a pointer to the address |
| 717 | of the dynamic link structure. */ |
| 718 | if (target_read_memory (dyn_ptr, pbuf, pbuf_size)) |
| 719 | return 0; |
| 720 | return extract_typed_address (pbuf, ptr_type); |
| 721 | } |
| 722 | |
| 723 | /* Find DT_DEBUG. */ |
| 724 | if (scan_dyntag (DT_DEBUG, exec_bfd, &dyn_ptr) |
| 725 | || scan_dyntag_auxv (DT_DEBUG, &dyn_ptr)) |
| 726 | return dyn_ptr; |
| 727 | |
| 728 | /* This may be a static executable. Look for the symbol |
| 729 | conventionally named _r_debug, as a last resort. */ |
| 730 | msymbol = lookup_minimal_symbol ("_r_debug", NULL, symfile_objfile); |
| 731 | if (msymbol != NULL) |
| 732 | return SYMBOL_VALUE_ADDRESS (msymbol); |
| 733 | |
| 734 | /* DT_DEBUG entry not found. */ |
| 735 | return 0; |
| 736 | } |
| 737 | |
| 738 | /* Locate the base address of dynamic linker structs. |
| 739 | |
| 740 | For both the SunOS and SVR4 shared library implementations, if the |
| 741 | inferior executable has been linked dynamically, there is a single |
| 742 | address somewhere in the inferior's data space which is the key to |
| 743 | locating all of the dynamic linker's runtime structures. This |
| 744 | address is the value of the debug base symbol. The job of this |
| 745 | function is to find and return that address, or to return 0 if there |
| 746 | is no such address (the executable is statically linked for example). |
| 747 | |
| 748 | For SunOS, the job is almost trivial, since the dynamic linker and |
| 749 | all of it's structures are statically linked to the executable at |
| 750 | link time. Thus the symbol for the address we are looking for has |
| 751 | already been added to the minimal symbol table for the executable's |
| 752 | objfile at the time the symbol file's symbols were read, and all we |
| 753 | have to do is look it up there. Note that we explicitly do NOT want |
| 754 | to find the copies in the shared library. |
| 755 | |
| 756 | The SVR4 version is a bit more complicated because the address |
| 757 | is contained somewhere in the dynamic info section. We have to go |
| 758 | to a lot more work to discover the address of the debug base symbol. |
| 759 | Because of this complexity, we cache the value we find and return that |
| 760 | value on subsequent invocations. Note there is no copy in the |
| 761 | executable symbol tables. */ |
| 762 | |
| 763 | static CORE_ADDR |
| 764 | locate_base (struct svr4_info *info) |
| 765 | { |
| 766 | /* Check to see if we have a currently valid address, and if so, avoid |
| 767 | doing all this work again and just return the cached address. If |
| 768 | we have no cached address, try to locate it in the dynamic info |
| 769 | section for ELF executables. There's no point in doing any of this |
| 770 | though if we don't have some link map offsets to work with. */ |
| 771 | |
| 772 | if (info->debug_base == 0 && svr4_have_link_map_offsets ()) |
| 773 | info->debug_base = elf_locate_base (); |
| 774 | return info->debug_base; |
| 775 | } |
| 776 | |
| 777 | /* Find the first element in the inferior's dynamic link map, and |
| 778 | return its address in the inferior. Return zero if the address |
| 779 | could not be determined. |
| 780 | |
| 781 | FIXME: Perhaps we should validate the info somehow, perhaps by |
| 782 | checking r_version for a known version number, or r_state for |
| 783 | RT_CONSISTENT. */ |
| 784 | |
| 785 | static CORE_ADDR |
| 786 | solib_svr4_r_map (struct svr4_info *info) |
| 787 | { |
| 788 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 789 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
| 790 | CORE_ADDR addr = 0; |
| 791 | volatile struct gdb_exception ex; |
| 792 | |
| 793 | TRY_CATCH (ex, RETURN_MASK_ERROR) |
| 794 | { |
| 795 | addr = read_memory_typed_address (info->debug_base + lmo->r_map_offset, |
| 796 | ptr_type); |
| 797 | } |
| 798 | exception_print (gdb_stderr, ex); |
| 799 | return addr; |
| 800 | } |
| 801 | |
| 802 | /* Find r_brk from the inferior's debug base. */ |
| 803 | |
| 804 | static CORE_ADDR |
| 805 | solib_svr4_r_brk (struct svr4_info *info) |
| 806 | { |
| 807 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 808 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
| 809 | |
| 810 | return read_memory_typed_address (info->debug_base + lmo->r_brk_offset, |
| 811 | ptr_type); |
| 812 | } |
| 813 | |
| 814 | /* Find the link map for the dynamic linker (if it is not in the |
| 815 | normal list of loaded shared objects). */ |
| 816 | |
| 817 | static CORE_ADDR |
| 818 | solib_svr4_r_ldsomap (struct svr4_info *info) |
| 819 | { |
| 820 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 821 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
| 822 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); |
| 823 | ULONGEST version; |
| 824 | |
| 825 | /* Check version, and return zero if `struct r_debug' doesn't have |
| 826 | the r_ldsomap member. */ |
| 827 | version |
| 828 | = read_memory_unsigned_integer (info->debug_base + lmo->r_version_offset, |
| 829 | lmo->r_version_size, byte_order); |
| 830 | if (version < 2 || lmo->r_ldsomap_offset == -1) |
| 831 | return 0; |
| 832 | |
| 833 | return read_memory_typed_address (info->debug_base + lmo->r_ldsomap_offset, |
| 834 | ptr_type); |
| 835 | } |
| 836 | |
| 837 | /* On Solaris systems with some versions of the dynamic linker, |
| 838 | ld.so's l_name pointer points to the SONAME in the string table |
| 839 | rather than into writable memory. So that GDB can find shared |
| 840 | libraries when loading a core file generated by gcore, ensure that |
| 841 | memory areas containing the l_name string are saved in the core |
| 842 | file. */ |
| 843 | |
| 844 | static int |
| 845 | svr4_keep_data_in_core (CORE_ADDR vaddr, unsigned long size) |
| 846 | { |
| 847 | struct svr4_info *info; |
| 848 | CORE_ADDR ldsomap; |
| 849 | struct so_list *new; |
| 850 | struct cleanup *old_chain; |
| 851 | struct link_map_offsets *lmo; |
| 852 | CORE_ADDR name_lm; |
| 853 | |
| 854 | info = get_svr4_info (); |
| 855 | |
| 856 | info->debug_base = 0; |
| 857 | locate_base (info); |
| 858 | if (!info->debug_base) |
| 859 | return 0; |
| 860 | |
| 861 | ldsomap = solib_svr4_r_ldsomap (info); |
| 862 | if (!ldsomap) |
| 863 | return 0; |
| 864 | |
| 865 | lmo = svr4_fetch_link_map_offsets (); |
| 866 | new = XZALLOC (struct so_list); |
| 867 | old_chain = make_cleanup (xfree, new); |
| 868 | new->lm_info = lm_info_read (ldsomap); |
| 869 | make_cleanup (xfree, new->lm_info); |
| 870 | name_lm = new->lm_info ? new->lm_info->l_name : 0; |
| 871 | do_cleanups (old_chain); |
| 872 | |
| 873 | return (name_lm >= vaddr && name_lm < vaddr + size); |
| 874 | } |
| 875 | |
| 876 | /* Implement the "open_symbol_file_object" target_so_ops method. |
| 877 | |
| 878 | If no open symbol file, attempt to locate and open the main symbol |
| 879 | file. On SVR4 systems, this is the first link map entry. If its |
| 880 | name is here, we can open it. Useful when attaching to a process |
| 881 | without first loading its symbol file. */ |
| 882 | |
| 883 | static int |
| 884 | open_symbol_file_object (void *from_ttyp) |
| 885 | { |
| 886 | CORE_ADDR lm, l_name; |
| 887 | char *filename; |
| 888 | int errcode; |
| 889 | int from_tty = *(int *)from_ttyp; |
| 890 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 891 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
| 892 | int l_name_size = TYPE_LENGTH (ptr_type); |
| 893 | gdb_byte *l_name_buf = xmalloc (l_name_size); |
| 894 | struct cleanup *cleanups = make_cleanup (xfree, l_name_buf); |
| 895 | struct svr4_info *info = get_svr4_info (); |
| 896 | |
| 897 | if (symfile_objfile) |
| 898 | if (!query (_("Attempt to reload symbols from process? "))) |
| 899 | { |
| 900 | do_cleanups (cleanups); |
| 901 | return 0; |
| 902 | } |
| 903 | |
| 904 | /* Always locate the debug struct, in case it has moved. */ |
| 905 | info->debug_base = 0; |
| 906 | if (locate_base (info) == 0) |
| 907 | { |
| 908 | do_cleanups (cleanups); |
| 909 | return 0; /* failed somehow... */ |
| 910 | } |
| 911 | |
| 912 | /* First link map member should be the executable. */ |
| 913 | lm = solib_svr4_r_map (info); |
| 914 | if (lm == 0) |
| 915 | { |
| 916 | do_cleanups (cleanups); |
| 917 | return 0; /* failed somehow... */ |
| 918 | } |
| 919 | |
| 920 | /* Read address of name from target memory to GDB. */ |
| 921 | read_memory (lm + lmo->l_name_offset, l_name_buf, l_name_size); |
| 922 | |
| 923 | /* Convert the address to host format. */ |
| 924 | l_name = extract_typed_address (l_name_buf, ptr_type); |
| 925 | |
| 926 | if (l_name == 0) |
| 927 | { |
| 928 | do_cleanups (cleanups); |
| 929 | return 0; /* No filename. */ |
| 930 | } |
| 931 | |
| 932 | /* Now fetch the filename from target memory. */ |
| 933 | target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode); |
| 934 | make_cleanup (xfree, filename); |
| 935 | |
| 936 | if (errcode) |
| 937 | { |
| 938 | warning (_("failed to read exec filename from attached file: %s"), |
| 939 | safe_strerror (errcode)); |
| 940 | do_cleanups (cleanups); |
| 941 | return 0; |
| 942 | } |
| 943 | |
| 944 | /* Have a pathname: read the symbol file. */ |
| 945 | symbol_file_add_main (filename, from_tty); |
| 946 | |
| 947 | do_cleanups (cleanups); |
| 948 | return 1; |
| 949 | } |
| 950 | |
| 951 | /* Data exchange structure for the XML parser as returned by |
| 952 | svr4_current_sos_via_xfer_libraries. */ |
| 953 | |
| 954 | struct svr4_library_list |
| 955 | { |
| 956 | struct so_list *head, **tailp; |
| 957 | |
| 958 | /* Inferior address of struct link_map used for the main executable. It is |
| 959 | NULL if not known. */ |
| 960 | CORE_ADDR main_lm; |
| 961 | }; |
| 962 | |
| 963 | /* Implementation for target_so_ops.free_so. */ |
| 964 | |
| 965 | static void |
| 966 | svr4_free_so (struct so_list *so) |
| 967 | { |
| 968 | xfree (so->lm_info); |
| 969 | } |
| 970 | |
| 971 | /* Free so_list built so far (called via cleanup). */ |
| 972 | |
| 973 | static void |
| 974 | svr4_free_library_list (void *p_list) |
| 975 | { |
| 976 | struct so_list *list = *(struct so_list **) p_list; |
| 977 | |
| 978 | while (list != NULL) |
| 979 | { |
| 980 | struct so_list *next = list->next; |
| 981 | |
| 982 | svr4_free_so (list); |
| 983 | list = next; |
| 984 | } |
| 985 | } |
| 986 | |
| 987 | #ifdef HAVE_LIBEXPAT |
| 988 | |
| 989 | #include "xml-support.h" |
| 990 | |
| 991 | /* Handle the start of a <library> element. Note: new elements are added |
| 992 | at the tail of the list, keeping the list in order. */ |
| 993 | |
| 994 | static void |
| 995 | library_list_start_library (struct gdb_xml_parser *parser, |
| 996 | const struct gdb_xml_element *element, |
| 997 | void *user_data, VEC(gdb_xml_value_s) *attributes) |
| 998 | { |
| 999 | struct svr4_library_list *list = user_data; |
| 1000 | const char *name = xml_find_attribute (attributes, "name")->value; |
| 1001 | ULONGEST *lmp = xml_find_attribute (attributes, "lm")->value; |
| 1002 | ULONGEST *l_addrp = xml_find_attribute (attributes, "l_addr")->value; |
| 1003 | ULONGEST *l_ldp = xml_find_attribute (attributes, "l_ld")->value; |
| 1004 | struct so_list *new_elem; |
| 1005 | |
| 1006 | new_elem = XZALLOC (struct so_list); |
| 1007 | new_elem->lm_info = XZALLOC (struct lm_info); |
| 1008 | new_elem->lm_info->lm_addr = *lmp; |
| 1009 | new_elem->lm_info->l_addr_inferior = *l_addrp; |
| 1010 | new_elem->lm_info->l_ld = *l_ldp; |
| 1011 | |
| 1012 | strncpy (new_elem->so_name, name, sizeof (new_elem->so_name) - 1); |
| 1013 | new_elem->so_name[sizeof (new_elem->so_name) - 1] = 0; |
| 1014 | strcpy (new_elem->so_original_name, new_elem->so_name); |
| 1015 | |
| 1016 | *list->tailp = new_elem; |
| 1017 | list->tailp = &new_elem->next; |
| 1018 | } |
| 1019 | |
| 1020 | /* Handle the start of a <library-list-svr4> element. */ |
| 1021 | |
| 1022 | static void |
| 1023 | svr4_library_list_start_list (struct gdb_xml_parser *parser, |
| 1024 | const struct gdb_xml_element *element, |
| 1025 | void *user_data, VEC(gdb_xml_value_s) *attributes) |
| 1026 | { |
| 1027 | struct svr4_library_list *list = user_data; |
| 1028 | const char *version = xml_find_attribute (attributes, "version")->value; |
| 1029 | struct gdb_xml_value *main_lm = xml_find_attribute (attributes, "main-lm"); |
| 1030 | |
| 1031 | if (strcmp (version, "1.0") != 0) |
| 1032 | gdb_xml_error (parser, |
| 1033 | _("SVR4 Library list has unsupported version \"%s\""), |
| 1034 | version); |
| 1035 | |
| 1036 | if (main_lm) |
| 1037 | list->main_lm = *(ULONGEST *) main_lm->value; |
| 1038 | } |
| 1039 | |
| 1040 | /* The allowed elements and attributes for an XML library list. |
| 1041 | The root element is a <library-list>. */ |
| 1042 | |
| 1043 | static const struct gdb_xml_attribute svr4_library_attributes[] = |
| 1044 | { |
| 1045 | { "name", GDB_XML_AF_NONE, NULL, NULL }, |
| 1046 | { "lm", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, |
| 1047 | { "l_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, |
| 1048 | { "l_ld", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, |
| 1049 | { NULL, GDB_XML_AF_NONE, NULL, NULL } |
| 1050 | }; |
| 1051 | |
| 1052 | static const struct gdb_xml_element svr4_library_list_children[] = |
| 1053 | { |
| 1054 | { |
| 1055 | "library", svr4_library_attributes, NULL, |
| 1056 | GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL, |
| 1057 | library_list_start_library, NULL |
| 1058 | }, |
| 1059 | { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL } |
| 1060 | }; |
| 1061 | |
| 1062 | static const struct gdb_xml_attribute svr4_library_list_attributes[] = |
| 1063 | { |
| 1064 | { "version", GDB_XML_AF_NONE, NULL, NULL }, |
| 1065 | { "main-lm", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL }, |
| 1066 | { NULL, GDB_XML_AF_NONE, NULL, NULL } |
| 1067 | }; |
| 1068 | |
| 1069 | static const struct gdb_xml_element svr4_library_list_elements[] = |
| 1070 | { |
| 1071 | { "library-list-svr4", svr4_library_list_attributes, svr4_library_list_children, |
| 1072 | GDB_XML_EF_NONE, svr4_library_list_start_list, NULL }, |
| 1073 | { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL } |
| 1074 | }; |
| 1075 | |
| 1076 | /* Parse qXfer:libraries:read packet into *SO_LIST_RETURN. Return 1 if |
| 1077 | |
| 1078 | Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such |
| 1079 | case. Return 1 if *SO_LIST_RETURN contains the library list, it may be |
| 1080 | empty, caller is responsible for freeing all its entries. */ |
| 1081 | |
| 1082 | static int |
| 1083 | svr4_parse_libraries (const char *document, struct svr4_library_list *list) |
| 1084 | { |
| 1085 | struct cleanup *back_to = make_cleanup (svr4_free_library_list, |
| 1086 | &list->head); |
| 1087 | |
| 1088 | memset (list, 0, sizeof (*list)); |
| 1089 | list->tailp = &list->head; |
| 1090 | if (gdb_xml_parse_quick (_("target library list"), "library-list.dtd", |
| 1091 | svr4_library_list_elements, document, list) == 0) |
| 1092 | { |
| 1093 | /* Parsed successfully, keep the result. */ |
| 1094 | discard_cleanups (back_to); |
| 1095 | return 1; |
| 1096 | } |
| 1097 | |
| 1098 | do_cleanups (back_to); |
| 1099 | return 0; |
| 1100 | } |
| 1101 | |
| 1102 | /* Attempt to get so_list from target via qXfer:libraries:read packet. |
| 1103 | |
| 1104 | Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such |
| 1105 | case. Return 1 if *SO_LIST_RETURN contains the library list, it may be |
| 1106 | empty, caller is responsible for freeing all its entries. */ |
| 1107 | |
| 1108 | static int |
| 1109 | svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list) |
| 1110 | { |
| 1111 | char *svr4_library_document; |
| 1112 | int result; |
| 1113 | struct cleanup *back_to; |
| 1114 | |
| 1115 | /* Fetch the list of shared libraries. */ |
| 1116 | svr4_library_document = target_read_stralloc (¤t_target, |
| 1117 | TARGET_OBJECT_LIBRARIES_SVR4, |
| 1118 | NULL); |
| 1119 | if (svr4_library_document == NULL) |
| 1120 | return 0; |
| 1121 | |
| 1122 | back_to = make_cleanup (xfree, svr4_library_document); |
| 1123 | result = svr4_parse_libraries (svr4_library_document, list); |
| 1124 | do_cleanups (back_to); |
| 1125 | |
| 1126 | return result; |
| 1127 | } |
| 1128 | |
| 1129 | #else |
| 1130 | |
| 1131 | static int |
| 1132 | svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list) |
| 1133 | { |
| 1134 | return 0; |
| 1135 | } |
| 1136 | |
| 1137 | #endif |
| 1138 | |
| 1139 | /* If no shared library information is available from the dynamic |
| 1140 | linker, build a fallback list from other sources. */ |
| 1141 | |
| 1142 | static struct so_list * |
| 1143 | svr4_default_sos (void) |
| 1144 | { |
| 1145 | struct svr4_info *info = get_svr4_info (); |
| 1146 | struct so_list *new; |
| 1147 | |
| 1148 | if (!info->debug_loader_offset_p) |
| 1149 | return NULL; |
| 1150 | |
| 1151 | new = XZALLOC (struct so_list); |
| 1152 | |
| 1153 | new->lm_info = xzalloc (sizeof (struct lm_info)); |
| 1154 | |
| 1155 | /* Nothing will ever check the other fields if we set l_addr_p. */ |
| 1156 | new->lm_info->l_addr = info->debug_loader_offset; |
| 1157 | new->lm_info->l_addr_p = 1; |
| 1158 | |
| 1159 | strncpy (new->so_name, info->debug_loader_name, SO_NAME_MAX_PATH_SIZE - 1); |
| 1160 | new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; |
| 1161 | strcpy (new->so_original_name, new->so_name); |
| 1162 | |
| 1163 | return new; |
| 1164 | } |
| 1165 | |
| 1166 | /* Read the whole inferior libraries chain starting at address LM. Add the |
| 1167 | entries to the tail referenced by LINK_PTR_PTR. Ignore the first entry if |
| 1168 | IGNORE_FIRST and set global MAIN_LM_ADDR according to it. */ |
| 1169 | |
| 1170 | static void |
| 1171 | svr4_read_so_list (CORE_ADDR lm, struct so_list ***link_ptr_ptr, |
| 1172 | int ignore_first) |
| 1173 | { |
| 1174 | CORE_ADDR prev_lm = 0, next_lm; |
| 1175 | |
| 1176 | for (; lm != 0; prev_lm = lm, lm = next_lm) |
| 1177 | { |
| 1178 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 1179 | struct so_list *new; |
| 1180 | struct cleanup *old_chain; |
| 1181 | int errcode; |
| 1182 | char *buffer; |
| 1183 | |
| 1184 | new = XZALLOC (struct so_list); |
| 1185 | old_chain = make_cleanup_free_so (new); |
| 1186 | |
| 1187 | new->lm_info = lm_info_read (lm); |
| 1188 | if (new->lm_info == NULL) |
| 1189 | { |
| 1190 | do_cleanups (old_chain); |
| 1191 | break; |
| 1192 | } |
| 1193 | |
| 1194 | next_lm = new->lm_info->l_next; |
| 1195 | |
| 1196 | if (new->lm_info->l_prev != prev_lm) |
| 1197 | { |
| 1198 | warning (_("Corrupted shared library list: %s != %s"), |
| 1199 | paddress (target_gdbarch, prev_lm), |
| 1200 | paddress (target_gdbarch, new->lm_info->l_prev)); |
| 1201 | do_cleanups (old_chain); |
| 1202 | break; |
| 1203 | } |
| 1204 | |
| 1205 | /* For SVR4 versions, the first entry in the link map is for the |
| 1206 | inferior executable, so we must ignore it. For some versions of |
| 1207 | SVR4, it has no name. For others (Solaris 2.3 for example), it |
| 1208 | does have a name, so we can no longer use a missing name to |
| 1209 | decide when to ignore it. */ |
| 1210 | if (ignore_first && new->lm_info->l_prev == 0) |
| 1211 | { |
| 1212 | struct svr4_info *info = get_svr4_info (); |
| 1213 | |
| 1214 | info->main_lm_addr = new->lm_info->lm_addr; |
| 1215 | do_cleanups (old_chain); |
| 1216 | continue; |
| 1217 | } |
| 1218 | |
| 1219 | /* Extract this shared object's name. */ |
| 1220 | target_read_string (new->lm_info->l_name, &buffer, |
| 1221 | SO_NAME_MAX_PATH_SIZE - 1, &errcode); |
| 1222 | if (errcode != 0) |
| 1223 | { |
| 1224 | warning (_("Can't read pathname for load map: %s."), |
| 1225 | safe_strerror (errcode)); |
| 1226 | do_cleanups (old_chain); |
| 1227 | continue; |
| 1228 | } |
| 1229 | |
| 1230 | strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1); |
| 1231 | new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; |
| 1232 | strcpy (new->so_original_name, new->so_name); |
| 1233 | xfree (buffer); |
| 1234 | |
| 1235 | /* If this entry has no name, or its name matches the name |
| 1236 | for the main executable, don't include it in the list. */ |
| 1237 | if (! new->so_name[0] || match_main (new->so_name)) |
| 1238 | { |
| 1239 | do_cleanups (old_chain); |
| 1240 | continue; |
| 1241 | } |
| 1242 | |
| 1243 | discard_cleanups (old_chain); |
| 1244 | new->next = 0; |
| 1245 | **link_ptr_ptr = new; |
| 1246 | *link_ptr_ptr = &new->next; |
| 1247 | } |
| 1248 | } |
| 1249 | |
| 1250 | /* Implement the "current_sos" target_so_ops method. */ |
| 1251 | |
| 1252 | static struct so_list * |
| 1253 | svr4_current_sos (void) |
| 1254 | { |
| 1255 | CORE_ADDR lm; |
| 1256 | struct so_list *head = NULL; |
| 1257 | struct so_list **link_ptr = &head; |
| 1258 | struct svr4_info *info; |
| 1259 | struct cleanup *back_to; |
| 1260 | int ignore_first; |
| 1261 | struct svr4_library_list library_list; |
| 1262 | |
| 1263 | if (svr4_current_sos_via_xfer_libraries (&library_list)) |
| 1264 | { |
| 1265 | if (library_list.main_lm) |
| 1266 | { |
| 1267 | info = get_svr4_info (); |
| 1268 | info->main_lm_addr = library_list.main_lm; |
| 1269 | } |
| 1270 | |
| 1271 | return library_list.head ? library_list.head : svr4_default_sos (); |
| 1272 | } |
| 1273 | |
| 1274 | info = get_svr4_info (); |
| 1275 | |
| 1276 | /* Always locate the debug struct, in case it has moved. */ |
| 1277 | info->debug_base = 0; |
| 1278 | locate_base (info); |
| 1279 | |
| 1280 | /* If we can't find the dynamic linker's base structure, this |
| 1281 | must not be a dynamically linked executable. Hmm. */ |
| 1282 | if (! info->debug_base) |
| 1283 | return svr4_default_sos (); |
| 1284 | |
| 1285 | /* Assume that everything is a library if the dynamic loader was loaded |
| 1286 | late by a static executable. */ |
| 1287 | if (exec_bfd && bfd_get_section_by_name (exec_bfd, ".dynamic") == NULL) |
| 1288 | ignore_first = 0; |
| 1289 | else |
| 1290 | ignore_first = 1; |
| 1291 | |
| 1292 | back_to = make_cleanup (svr4_free_library_list, &head); |
| 1293 | |
| 1294 | /* Walk the inferior's link map list, and build our list of |
| 1295 | `struct so_list' nodes. */ |
| 1296 | lm = solib_svr4_r_map (info); |
| 1297 | if (lm) |
| 1298 | svr4_read_so_list (lm, &link_ptr, ignore_first); |
| 1299 | |
| 1300 | /* On Solaris, the dynamic linker is not in the normal list of |
| 1301 | shared objects, so make sure we pick it up too. Having |
| 1302 | symbol information for the dynamic linker is quite crucial |
| 1303 | for skipping dynamic linker resolver code. */ |
| 1304 | lm = solib_svr4_r_ldsomap (info); |
| 1305 | if (lm) |
| 1306 | svr4_read_so_list (lm, &link_ptr, 0); |
| 1307 | |
| 1308 | discard_cleanups (back_to); |
| 1309 | |
| 1310 | if (head == NULL) |
| 1311 | return svr4_default_sos (); |
| 1312 | |
| 1313 | return head; |
| 1314 | } |
| 1315 | |
| 1316 | /* Get the address of the link_map for a given OBJFILE. */ |
| 1317 | |
| 1318 | CORE_ADDR |
| 1319 | svr4_fetch_objfile_link_map (struct objfile *objfile) |
| 1320 | { |
| 1321 | struct so_list *so; |
| 1322 | struct svr4_info *info = get_svr4_info (); |
| 1323 | |
| 1324 | /* Cause svr4_current_sos() to be run if it hasn't been already. */ |
| 1325 | if (info->main_lm_addr == 0) |
| 1326 | solib_add (NULL, 0, ¤t_target, auto_solib_add); |
| 1327 | |
| 1328 | /* svr4_current_sos() will set main_lm_addr for the main executable. */ |
| 1329 | if (objfile == symfile_objfile) |
| 1330 | return info->main_lm_addr; |
| 1331 | |
| 1332 | /* The other link map addresses may be found by examining the list |
| 1333 | of shared libraries. */ |
| 1334 | for (so = master_so_list (); so; so = so->next) |
| 1335 | if (so->objfile == objfile) |
| 1336 | return so->lm_info->lm_addr; |
| 1337 | |
| 1338 | /* Not found! */ |
| 1339 | return 0; |
| 1340 | } |
| 1341 | |
| 1342 | /* On some systems, the only way to recognize the link map entry for |
| 1343 | the main executable file is by looking at its name. Return |
| 1344 | non-zero iff SONAME matches one of the known main executable names. */ |
| 1345 | |
| 1346 | static int |
| 1347 | match_main (const char *soname) |
| 1348 | { |
| 1349 | const char * const *mainp; |
| 1350 | |
| 1351 | for (mainp = main_name_list; *mainp != NULL; mainp++) |
| 1352 | { |
| 1353 | if (strcmp (soname, *mainp) == 0) |
| 1354 | return (1); |
| 1355 | } |
| 1356 | |
| 1357 | return (0); |
| 1358 | } |
| 1359 | |
| 1360 | /* Return 1 if PC lies in the dynamic symbol resolution code of the |
| 1361 | SVR4 run time loader. */ |
| 1362 | |
| 1363 | int |
| 1364 | svr4_in_dynsym_resolve_code (CORE_ADDR pc) |
| 1365 | { |
| 1366 | struct svr4_info *info = get_svr4_info (); |
| 1367 | |
| 1368 | return ((pc >= info->interp_text_sect_low |
| 1369 | && pc < info->interp_text_sect_high) |
| 1370 | || (pc >= info->interp_plt_sect_low |
| 1371 | && pc < info->interp_plt_sect_high) |
| 1372 | || in_plt_section (pc, NULL) |
| 1373 | || in_gnu_ifunc_stub (pc)); |
| 1374 | } |
| 1375 | |
| 1376 | /* Given an executable's ABFD and target, compute the entry-point |
| 1377 | address. */ |
| 1378 | |
| 1379 | static CORE_ADDR |
| 1380 | exec_entry_point (struct bfd *abfd, struct target_ops *targ) |
| 1381 | { |
| 1382 | /* KevinB wrote ... for most targets, the address returned by |
| 1383 | bfd_get_start_address() is the entry point for the start |
| 1384 | function. But, for some targets, bfd_get_start_address() returns |
| 1385 | the address of a function descriptor from which the entry point |
| 1386 | address may be extracted. This address is extracted by |
| 1387 | gdbarch_convert_from_func_ptr_addr(). The method |
| 1388 | gdbarch_convert_from_func_ptr_addr() is the merely the identify |
| 1389 | function for targets which don't use function descriptors. */ |
| 1390 | return gdbarch_convert_from_func_ptr_addr (target_gdbarch, |
| 1391 | bfd_get_start_address (abfd), |
| 1392 | targ); |
| 1393 | } |
| 1394 | |
| 1395 | /* Helper function for gdb_bfd_lookup_symbol. */ |
| 1396 | |
| 1397 | static int |
| 1398 | cmp_name_and_sec_flags (asymbol *sym, void *data) |
| 1399 | { |
| 1400 | return (strcmp (sym->name, (const char *) data) == 0 |
| 1401 | && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0); |
| 1402 | } |
| 1403 | /* Arrange for dynamic linker to hit breakpoint. |
| 1404 | |
| 1405 | Both the SunOS and the SVR4 dynamic linkers have, as part of their |
| 1406 | debugger interface, support for arranging for the inferior to hit |
| 1407 | a breakpoint after mapping in the shared libraries. This function |
| 1408 | enables that breakpoint. |
| 1409 | |
| 1410 | For SunOS, there is a special flag location (in_debugger) which we |
| 1411 | set to 1. When the dynamic linker sees this flag set, it will set |
| 1412 | a breakpoint at a location known only to itself, after saving the |
| 1413 | original contents of that place and the breakpoint address itself, |
| 1414 | in it's own internal structures. When we resume the inferior, it |
| 1415 | will eventually take a SIGTRAP when it runs into the breakpoint. |
| 1416 | We handle this (in a different place) by restoring the contents of |
| 1417 | the breakpointed location (which is only known after it stops), |
| 1418 | chasing around to locate the shared libraries that have been |
| 1419 | loaded, then resuming. |
| 1420 | |
| 1421 | For SVR4, the debugger interface structure contains a member (r_brk) |
| 1422 | which is statically initialized at the time the shared library is |
| 1423 | built, to the offset of a function (_r_debug_state) which is guaran- |
| 1424 | teed to be called once before mapping in a library, and again when |
| 1425 | the mapping is complete. At the time we are examining this member, |
| 1426 | it contains only the unrelocated offset of the function, so we have |
| 1427 | to do our own relocation. Later, when the dynamic linker actually |
| 1428 | runs, it relocates r_brk to be the actual address of _r_debug_state(). |
| 1429 | |
| 1430 | The debugger interface structure also contains an enumeration which |
| 1431 | is set to either RT_ADD or RT_DELETE prior to changing the mapping, |
| 1432 | depending upon whether or not the library is being mapped or unmapped, |
| 1433 | and then set to RT_CONSISTENT after the library is mapped/unmapped. */ |
| 1434 | |
| 1435 | static int |
| 1436 | enable_break (struct svr4_info *info, int from_tty) |
| 1437 | { |
| 1438 | struct minimal_symbol *msymbol; |
| 1439 | const char * const *bkpt_namep; |
| 1440 | asection *interp_sect; |
| 1441 | gdb_byte *interp_name; |
| 1442 | CORE_ADDR sym_addr; |
| 1443 | |
| 1444 | info->interp_text_sect_low = info->interp_text_sect_high = 0; |
| 1445 | info->interp_plt_sect_low = info->interp_plt_sect_high = 0; |
| 1446 | |
| 1447 | /* If we already have a shared library list in the target, and |
| 1448 | r_debug contains r_brk, set the breakpoint there - this should |
| 1449 | mean r_brk has already been relocated. Assume the dynamic linker |
| 1450 | is the object containing r_brk. */ |
| 1451 | |
| 1452 | solib_add (NULL, from_tty, ¤t_target, auto_solib_add); |
| 1453 | sym_addr = 0; |
| 1454 | if (info->debug_base && solib_svr4_r_map (info) != 0) |
| 1455 | sym_addr = solib_svr4_r_brk (info); |
| 1456 | |
| 1457 | if (sym_addr != 0) |
| 1458 | { |
| 1459 | struct obj_section *os; |
| 1460 | |
| 1461 | sym_addr = gdbarch_addr_bits_remove |
| 1462 | (target_gdbarch, gdbarch_convert_from_func_ptr_addr (target_gdbarch, |
| 1463 | sym_addr, |
| 1464 | ¤t_target)); |
| 1465 | |
| 1466 | /* On at least some versions of Solaris there's a dynamic relocation |
| 1467 | on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if |
| 1468 | we get control before the dynamic linker has self-relocated. |
| 1469 | Check if SYM_ADDR is in a known section, if it is assume we can |
| 1470 | trust its value. This is just a heuristic though, it could go away |
| 1471 | or be replaced if it's getting in the way. |
| 1472 | |
| 1473 | On ARM we need to know whether the ISA of rtld_db_dlactivity (or |
| 1474 | however it's spelled in your particular system) is ARM or Thumb. |
| 1475 | That knowledge is encoded in the address, if it's Thumb the low bit |
| 1476 | is 1. However, we've stripped that info above and it's not clear |
| 1477 | what all the consequences are of passing a non-addr_bits_remove'd |
| 1478 | address to create_solib_event_breakpoint. The call to |
| 1479 | find_pc_section verifies we know about the address and have some |
| 1480 | hope of computing the right kind of breakpoint to use (via |
| 1481 | symbol info). It does mean that GDB needs to be pointed at a |
| 1482 | non-stripped version of the dynamic linker in order to obtain |
| 1483 | information it already knows about. Sigh. */ |
| 1484 | |
| 1485 | os = find_pc_section (sym_addr); |
| 1486 | if (os != NULL) |
| 1487 | { |
| 1488 | /* Record the relocated start and end address of the dynamic linker |
| 1489 | text and plt section for svr4_in_dynsym_resolve_code. */ |
| 1490 | bfd *tmp_bfd; |
| 1491 | CORE_ADDR load_addr; |
| 1492 | |
| 1493 | tmp_bfd = os->objfile->obfd; |
| 1494 | load_addr = ANOFFSET (os->objfile->section_offsets, |
| 1495 | os->objfile->sect_index_text); |
| 1496 | |
| 1497 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
| 1498 | if (interp_sect) |
| 1499 | { |
| 1500 | info->interp_text_sect_low = |
| 1501 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| 1502 | info->interp_text_sect_high = |
| 1503 | info->interp_text_sect_low |
| 1504 | + bfd_section_size (tmp_bfd, interp_sect); |
| 1505 | } |
| 1506 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); |
| 1507 | if (interp_sect) |
| 1508 | { |
| 1509 | info->interp_plt_sect_low = |
| 1510 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| 1511 | info->interp_plt_sect_high = |
| 1512 | info->interp_plt_sect_low |
| 1513 | + bfd_section_size (tmp_bfd, interp_sect); |
| 1514 | } |
| 1515 | |
| 1516 | create_solib_event_breakpoint (target_gdbarch, sym_addr); |
| 1517 | return 1; |
| 1518 | } |
| 1519 | } |
| 1520 | |
| 1521 | /* Find the program interpreter; if not found, warn the user and drop |
| 1522 | into the old breakpoint at symbol code. */ |
| 1523 | interp_name = find_program_interpreter (); |
| 1524 | if (interp_name) |
| 1525 | { |
| 1526 | CORE_ADDR load_addr = 0; |
| 1527 | int load_addr_found = 0; |
| 1528 | int loader_found_in_list = 0; |
| 1529 | struct so_list *so; |
| 1530 | bfd *tmp_bfd = NULL; |
| 1531 | struct target_ops *tmp_bfd_target; |
| 1532 | volatile struct gdb_exception ex; |
| 1533 | |
| 1534 | sym_addr = 0; |
| 1535 | |
| 1536 | /* Now we need to figure out where the dynamic linker was |
| 1537 | loaded so that we can load its symbols and place a breakpoint |
| 1538 | in the dynamic linker itself. |
| 1539 | |
| 1540 | This address is stored on the stack. However, I've been unable |
| 1541 | to find any magic formula to find it for Solaris (appears to |
| 1542 | be trivial on GNU/Linux). Therefore, we have to try an alternate |
| 1543 | mechanism to find the dynamic linker's base address. */ |
| 1544 | |
| 1545 | TRY_CATCH (ex, RETURN_MASK_ALL) |
| 1546 | { |
| 1547 | tmp_bfd = solib_bfd_open (interp_name); |
| 1548 | } |
| 1549 | if (tmp_bfd == NULL) |
| 1550 | goto bkpt_at_symbol; |
| 1551 | |
| 1552 | /* Now convert the TMP_BFD into a target. That way target, as |
| 1553 | well as BFD operations can be used. Note that closing the |
| 1554 | target will also close the underlying bfd. */ |
| 1555 | tmp_bfd_target = target_bfd_reopen (tmp_bfd); |
| 1556 | |
| 1557 | /* On a running target, we can get the dynamic linker's base |
| 1558 | address from the shared library table. */ |
| 1559 | so = master_so_list (); |
| 1560 | while (so) |
| 1561 | { |
| 1562 | if (svr4_same_1 (interp_name, so->so_original_name)) |
| 1563 | { |
| 1564 | load_addr_found = 1; |
| 1565 | loader_found_in_list = 1; |
| 1566 | load_addr = lm_addr_check (so, tmp_bfd); |
| 1567 | break; |
| 1568 | } |
| 1569 | so = so->next; |
| 1570 | } |
| 1571 | |
| 1572 | /* If we were not able to find the base address of the loader |
| 1573 | from our so_list, then try using the AT_BASE auxilliary entry. */ |
| 1574 | if (!load_addr_found) |
| 1575 | if (target_auxv_search (¤t_target, AT_BASE, &load_addr) > 0) |
| 1576 | { |
| 1577 | int addr_bit = gdbarch_addr_bit (target_gdbarch); |
| 1578 | |
| 1579 | /* Ensure LOAD_ADDR has proper sign in its possible upper bits so |
| 1580 | that `+ load_addr' will overflow CORE_ADDR width not creating |
| 1581 | invalid addresses like 0x101234567 for 32bit inferiors on 64bit |
| 1582 | GDB. */ |
| 1583 | |
| 1584 | if (addr_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT)) |
| 1585 | { |
| 1586 | CORE_ADDR space_size = (CORE_ADDR) 1 << addr_bit; |
| 1587 | CORE_ADDR tmp_entry_point = exec_entry_point (tmp_bfd, |
| 1588 | tmp_bfd_target); |
| 1589 | |
| 1590 | gdb_assert (load_addr < space_size); |
| 1591 | |
| 1592 | /* TMP_ENTRY_POINT exceeding SPACE_SIZE would be for prelinked |
| 1593 | 64bit ld.so with 32bit executable, it should not happen. */ |
| 1594 | |
| 1595 | if (tmp_entry_point < space_size |
| 1596 | && tmp_entry_point + load_addr >= space_size) |
| 1597 | load_addr -= space_size; |
| 1598 | } |
| 1599 | |
| 1600 | load_addr_found = 1; |
| 1601 | } |
| 1602 | |
| 1603 | /* Otherwise we find the dynamic linker's base address by examining |
| 1604 | the current pc (which should point at the entry point for the |
| 1605 | dynamic linker) and subtracting the offset of the entry point. |
| 1606 | |
| 1607 | This is more fragile than the previous approaches, but is a good |
| 1608 | fallback method because it has actually been working well in |
| 1609 | most cases. */ |
| 1610 | if (!load_addr_found) |
| 1611 | { |
| 1612 | struct regcache *regcache |
| 1613 | = get_thread_arch_regcache (inferior_ptid, target_gdbarch); |
| 1614 | |
| 1615 | load_addr = (regcache_read_pc (regcache) |
| 1616 | - exec_entry_point (tmp_bfd, tmp_bfd_target)); |
| 1617 | } |
| 1618 | |
| 1619 | if (!loader_found_in_list) |
| 1620 | { |
| 1621 | info->debug_loader_name = xstrdup (interp_name); |
| 1622 | info->debug_loader_offset_p = 1; |
| 1623 | info->debug_loader_offset = load_addr; |
| 1624 | solib_add (NULL, from_tty, ¤t_target, auto_solib_add); |
| 1625 | } |
| 1626 | |
| 1627 | /* Record the relocated start and end address of the dynamic linker |
| 1628 | text and plt section for svr4_in_dynsym_resolve_code. */ |
| 1629 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
| 1630 | if (interp_sect) |
| 1631 | { |
| 1632 | info->interp_text_sect_low = |
| 1633 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| 1634 | info->interp_text_sect_high = |
| 1635 | info->interp_text_sect_low |
| 1636 | + bfd_section_size (tmp_bfd, interp_sect); |
| 1637 | } |
| 1638 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); |
| 1639 | if (interp_sect) |
| 1640 | { |
| 1641 | info->interp_plt_sect_low = |
| 1642 | bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| 1643 | info->interp_plt_sect_high = |
| 1644 | info->interp_plt_sect_low |
| 1645 | + bfd_section_size (tmp_bfd, interp_sect); |
| 1646 | } |
| 1647 | |
| 1648 | /* Now try to set a breakpoint in the dynamic linker. */ |
| 1649 | for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) |
| 1650 | { |
| 1651 | sym_addr = gdb_bfd_lookup_symbol (tmp_bfd, cmp_name_and_sec_flags, |
| 1652 | (void *) *bkpt_namep); |
| 1653 | if (sym_addr != 0) |
| 1654 | break; |
| 1655 | } |
| 1656 | |
| 1657 | if (sym_addr != 0) |
| 1658 | /* Convert 'sym_addr' from a function pointer to an address. |
| 1659 | Because we pass tmp_bfd_target instead of the current |
| 1660 | target, this will always produce an unrelocated value. */ |
| 1661 | sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch, |
| 1662 | sym_addr, |
| 1663 | tmp_bfd_target); |
| 1664 | |
| 1665 | /* We're done with both the temporary bfd and target. Remember, |
| 1666 | closing the target closes the underlying bfd. */ |
| 1667 | target_close (tmp_bfd_target, 0); |
| 1668 | |
| 1669 | if (sym_addr != 0) |
| 1670 | { |
| 1671 | create_solib_event_breakpoint (target_gdbarch, load_addr + sym_addr); |
| 1672 | xfree (interp_name); |
| 1673 | return 1; |
| 1674 | } |
| 1675 | |
| 1676 | /* For whatever reason we couldn't set a breakpoint in the dynamic |
| 1677 | linker. Warn and drop into the old code. */ |
| 1678 | bkpt_at_symbol: |
| 1679 | xfree (interp_name); |
| 1680 | warning (_("Unable to find dynamic linker breakpoint function.\n" |
| 1681 | "GDB will be unable to debug shared library initializers\n" |
| 1682 | "and track explicitly loaded dynamic code.")); |
| 1683 | } |
| 1684 | |
| 1685 | /* Scan through the lists of symbols, trying to look up the symbol and |
| 1686 | set a breakpoint there. Terminate loop when we/if we succeed. */ |
| 1687 | |
| 1688 | for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) |
| 1689 | { |
| 1690 | msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); |
| 1691 | if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) |
| 1692 | { |
| 1693 | sym_addr = SYMBOL_VALUE_ADDRESS (msymbol); |
| 1694 | sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch, |
| 1695 | sym_addr, |
| 1696 | ¤t_target); |
| 1697 | create_solib_event_breakpoint (target_gdbarch, sym_addr); |
| 1698 | return 1; |
| 1699 | } |
| 1700 | } |
| 1701 | |
| 1702 | if (!current_inferior ()->attach_flag) |
| 1703 | { |
| 1704 | for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++) |
| 1705 | { |
| 1706 | msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); |
| 1707 | if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) |
| 1708 | { |
| 1709 | sym_addr = SYMBOL_VALUE_ADDRESS (msymbol); |
| 1710 | sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch, |
| 1711 | sym_addr, |
| 1712 | ¤t_target); |
| 1713 | create_solib_event_breakpoint (target_gdbarch, sym_addr); |
| 1714 | return 1; |
| 1715 | } |
| 1716 | } |
| 1717 | } |
| 1718 | return 0; |
| 1719 | } |
| 1720 | |
| 1721 | /* Implement the "special_symbol_handling" target_so_ops method. */ |
| 1722 | |
| 1723 | static void |
| 1724 | svr4_special_symbol_handling (void) |
| 1725 | { |
| 1726 | /* Nothing to do. */ |
| 1727 | } |
| 1728 | |
| 1729 | /* Read the ELF program headers from ABFD. Return the contents and |
| 1730 | set *PHDRS_SIZE to the size of the program headers. */ |
| 1731 | |
| 1732 | static gdb_byte * |
| 1733 | read_program_headers_from_bfd (bfd *abfd, int *phdrs_size) |
| 1734 | { |
| 1735 | Elf_Internal_Ehdr *ehdr; |
| 1736 | gdb_byte *buf; |
| 1737 | |
| 1738 | ehdr = elf_elfheader (abfd); |
| 1739 | |
| 1740 | *phdrs_size = ehdr->e_phnum * ehdr->e_phentsize; |
| 1741 | if (*phdrs_size == 0) |
| 1742 | return NULL; |
| 1743 | |
| 1744 | buf = xmalloc (*phdrs_size); |
| 1745 | if (bfd_seek (abfd, ehdr->e_phoff, SEEK_SET) != 0 |
| 1746 | || bfd_bread (buf, *phdrs_size, abfd) != *phdrs_size) |
| 1747 | { |
| 1748 | xfree (buf); |
| 1749 | return NULL; |
| 1750 | } |
| 1751 | |
| 1752 | return buf; |
| 1753 | } |
| 1754 | |
| 1755 | /* Return 1 and fill *DISPLACEMENTP with detected PIE offset of inferior |
| 1756 | exec_bfd. Otherwise return 0. |
| 1757 | |
| 1758 | We relocate all of the sections by the same amount. This |
| 1759 | behavior is mandated by recent editions of the System V ABI. |
| 1760 | According to the System V Application Binary Interface, |
| 1761 | Edition 4.1, page 5-5: |
| 1762 | |
| 1763 | ... Though the system chooses virtual addresses for |
| 1764 | individual processes, it maintains the segments' relative |
| 1765 | positions. Because position-independent code uses relative |
| 1766 | addressesing between segments, the difference between |
| 1767 | virtual addresses in memory must match the difference |
| 1768 | between virtual addresses in the file. The difference |
| 1769 | between the virtual address of any segment in memory and |
| 1770 | the corresponding virtual address in the file is thus a |
| 1771 | single constant value for any one executable or shared |
| 1772 | object in a given process. This difference is the base |
| 1773 | address. One use of the base address is to relocate the |
| 1774 | memory image of the program during dynamic linking. |
| 1775 | |
| 1776 | The same language also appears in Edition 4.0 of the System V |
| 1777 | ABI and is left unspecified in some of the earlier editions. |
| 1778 | |
| 1779 | Decide if the objfile needs to be relocated. As indicated above, we will |
| 1780 | only be here when execution is stopped. But during attachment PC can be at |
| 1781 | arbitrary address therefore regcache_read_pc can be misleading (contrary to |
| 1782 | the auxv AT_ENTRY value). Moreover for executable with interpreter section |
| 1783 | regcache_read_pc would point to the interpreter and not the main executable. |
| 1784 | |
| 1785 | So, to summarize, relocations are necessary when the start address obtained |
| 1786 | from the executable is different from the address in auxv AT_ENTRY entry. |
| 1787 | |
| 1788 | [ The astute reader will note that we also test to make sure that |
| 1789 | the executable in question has the DYNAMIC flag set. It is my |
| 1790 | opinion that this test is unnecessary (undesirable even). It |
| 1791 | was added to avoid inadvertent relocation of an executable |
| 1792 | whose e_type member in the ELF header is not ET_DYN. There may |
| 1793 | be a time in the future when it is desirable to do relocations |
| 1794 | on other types of files as well in which case this condition |
| 1795 | should either be removed or modified to accomodate the new file |
| 1796 | type. - Kevin, Nov 2000. ] */ |
| 1797 | |
| 1798 | static int |
| 1799 | svr4_exec_displacement (CORE_ADDR *displacementp) |
| 1800 | { |
| 1801 | /* ENTRY_POINT is a possible function descriptor - before |
| 1802 | a call to gdbarch_convert_from_func_ptr_addr. */ |
| 1803 | CORE_ADDR entry_point, displacement; |
| 1804 | |
| 1805 | if (exec_bfd == NULL) |
| 1806 | return 0; |
| 1807 | |
| 1808 | /* Therefore for ELF it is ET_EXEC and not ET_DYN. Both shared libraries |
| 1809 | being executed themselves and PIE (Position Independent Executable) |
| 1810 | executables are ET_DYN. */ |
| 1811 | |
| 1812 | if ((bfd_get_file_flags (exec_bfd) & DYNAMIC) == 0) |
| 1813 | return 0; |
| 1814 | |
| 1815 | if (target_auxv_search (¤t_target, AT_ENTRY, &entry_point) <= 0) |
| 1816 | return 0; |
| 1817 | |
| 1818 | displacement = entry_point - bfd_get_start_address (exec_bfd); |
| 1819 | |
| 1820 | /* Verify the DISPLACEMENT candidate complies with the required page |
| 1821 | alignment. It is cheaper than the program headers comparison below. */ |
| 1822 | |
| 1823 | if (bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) |
| 1824 | { |
| 1825 | const struct elf_backend_data *elf = get_elf_backend_data (exec_bfd); |
| 1826 | |
| 1827 | /* p_align of PT_LOAD segments does not specify any alignment but |
| 1828 | only congruency of addresses: |
| 1829 | p_offset % p_align == p_vaddr % p_align |
| 1830 | Kernel is free to load the executable with lower alignment. */ |
| 1831 | |
| 1832 | if ((displacement & (elf->minpagesize - 1)) != 0) |
| 1833 | return 0; |
| 1834 | } |
| 1835 | |
| 1836 | /* Verify that the auxilliary vector describes the same file as exec_bfd, by |
| 1837 | comparing their program headers. If the program headers in the auxilliary |
| 1838 | vector do not match the program headers in the executable, then we are |
| 1839 | looking at a different file than the one used by the kernel - for |
| 1840 | instance, "gdb program" connected to "gdbserver :PORT ld.so program". */ |
| 1841 | |
| 1842 | if (bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) |
| 1843 | { |
| 1844 | /* Be optimistic and clear OK only if GDB was able to verify the headers |
| 1845 | really do not match. */ |
| 1846 | int phdrs_size, phdrs2_size, ok = 1; |
| 1847 | gdb_byte *buf, *buf2; |
| 1848 | int arch_size; |
| 1849 | |
| 1850 | buf = read_program_header (-1, &phdrs_size, &arch_size); |
| 1851 | buf2 = read_program_headers_from_bfd (exec_bfd, &phdrs2_size); |
| 1852 | if (buf != NULL && buf2 != NULL) |
| 1853 | { |
| 1854 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); |
| 1855 | |
| 1856 | /* We are dealing with three different addresses. EXEC_BFD |
| 1857 | represents current address in on-disk file. target memory content |
| 1858 | may be different from EXEC_BFD as the file may have been prelinked |
| 1859 | to a different address after the executable has been loaded. |
| 1860 | Moreover the address of placement in target memory can be |
| 1861 | different from what the program headers in target memory say - |
| 1862 | this is the goal of PIE. |
| 1863 | |
| 1864 | Detected DISPLACEMENT covers both the offsets of PIE placement and |
| 1865 | possible new prelink performed after start of the program. Here |
| 1866 | relocate BUF and BUF2 just by the EXEC_BFD vs. target memory |
| 1867 | content offset for the verification purpose. */ |
| 1868 | |
| 1869 | if (phdrs_size != phdrs2_size |
| 1870 | || bfd_get_arch_size (exec_bfd) != arch_size) |
| 1871 | ok = 0; |
| 1872 | else if (arch_size == 32 |
| 1873 | && phdrs_size >= sizeof (Elf32_External_Phdr) |
| 1874 | && phdrs_size % sizeof (Elf32_External_Phdr) == 0) |
| 1875 | { |
| 1876 | Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header; |
| 1877 | Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr; |
| 1878 | CORE_ADDR displacement = 0; |
| 1879 | int i; |
| 1880 | |
| 1881 | /* DISPLACEMENT could be found more easily by the difference of |
| 1882 | ehdr2->e_entry. But we haven't read the ehdr yet, and we |
| 1883 | already have enough information to compute that displacement |
| 1884 | with what we've read. */ |
| 1885 | |
| 1886 | for (i = 0; i < ehdr2->e_phnum; i++) |
| 1887 | if (phdr2[i].p_type == PT_LOAD) |
| 1888 | { |
| 1889 | Elf32_External_Phdr *phdrp; |
| 1890 | gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| 1891 | CORE_ADDR vaddr, paddr; |
| 1892 | CORE_ADDR displacement_vaddr = 0; |
| 1893 | CORE_ADDR displacement_paddr = 0; |
| 1894 | |
| 1895 | phdrp = &((Elf32_External_Phdr *) buf)[i]; |
| 1896 | buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| 1897 | buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| 1898 | |
| 1899 | vaddr = extract_unsigned_integer (buf_vaddr_p, 4, |
| 1900 | byte_order); |
| 1901 | displacement_vaddr = vaddr - phdr2[i].p_vaddr; |
| 1902 | |
| 1903 | paddr = extract_unsigned_integer (buf_paddr_p, 4, |
| 1904 | byte_order); |
| 1905 | displacement_paddr = paddr - phdr2[i].p_paddr; |
| 1906 | |
| 1907 | if (displacement_vaddr == displacement_paddr) |
| 1908 | displacement = displacement_vaddr; |
| 1909 | |
| 1910 | break; |
| 1911 | } |
| 1912 | |
| 1913 | /* Now compare BUF and BUF2 with optional DISPLACEMENT. */ |
| 1914 | |
| 1915 | for (i = 0; i < phdrs_size / sizeof (Elf32_External_Phdr); i++) |
| 1916 | { |
| 1917 | Elf32_External_Phdr *phdrp; |
| 1918 | Elf32_External_Phdr *phdr2p; |
| 1919 | gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| 1920 | CORE_ADDR vaddr, paddr; |
| 1921 | asection *plt2_asect; |
| 1922 | |
| 1923 | phdrp = &((Elf32_External_Phdr *) buf)[i]; |
| 1924 | buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| 1925 | buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| 1926 | phdr2p = &((Elf32_External_Phdr *) buf2)[i]; |
| 1927 | |
| 1928 | /* PT_GNU_STACK is an exception by being never relocated by |
| 1929 | prelink as its addresses are always zero. */ |
| 1930 | |
| 1931 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 1932 | continue; |
| 1933 | |
| 1934 | /* Check also other adjustment combinations - PR 11786. */ |
| 1935 | |
| 1936 | vaddr = extract_unsigned_integer (buf_vaddr_p, 4, |
| 1937 | byte_order); |
| 1938 | vaddr -= displacement; |
| 1939 | store_unsigned_integer (buf_vaddr_p, 4, byte_order, vaddr); |
| 1940 | |
| 1941 | paddr = extract_unsigned_integer (buf_paddr_p, 4, |
| 1942 | byte_order); |
| 1943 | paddr -= displacement; |
| 1944 | store_unsigned_integer (buf_paddr_p, 4, byte_order, paddr); |
| 1945 | |
| 1946 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 1947 | continue; |
| 1948 | |
| 1949 | /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */ |
| 1950 | plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt"); |
| 1951 | if (plt2_asect) |
| 1952 | { |
| 1953 | int content2; |
| 1954 | gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz; |
| 1955 | CORE_ADDR filesz; |
| 1956 | |
| 1957 | content2 = (bfd_get_section_flags (exec_bfd, plt2_asect) |
| 1958 | & SEC_HAS_CONTENTS) != 0; |
| 1959 | |
| 1960 | filesz = extract_unsigned_integer (buf_filesz_p, 4, |
| 1961 | byte_order); |
| 1962 | |
| 1963 | /* PLT2_ASECT is from on-disk file (exec_bfd) while |
| 1964 | FILESZ is from the in-memory image. */ |
| 1965 | if (content2) |
| 1966 | filesz += bfd_get_section_size (plt2_asect); |
| 1967 | else |
| 1968 | filesz -= bfd_get_section_size (plt2_asect); |
| 1969 | |
| 1970 | store_unsigned_integer (buf_filesz_p, 4, byte_order, |
| 1971 | filesz); |
| 1972 | |
| 1973 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 1974 | continue; |
| 1975 | } |
| 1976 | |
| 1977 | ok = 0; |
| 1978 | break; |
| 1979 | } |
| 1980 | } |
| 1981 | else if (arch_size == 64 |
| 1982 | && phdrs_size >= sizeof (Elf64_External_Phdr) |
| 1983 | && phdrs_size % sizeof (Elf64_External_Phdr) == 0) |
| 1984 | { |
| 1985 | Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header; |
| 1986 | Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr; |
| 1987 | CORE_ADDR displacement = 0; |
| 1988 | int i; |
| 1989 | |
| 1990 | /* DISPLACEMENT could be found more easily by the difference of |
| 1991 | ehdr2->e_entry. But we haven't read the ehdr yet, and we |
| 1992 | already have enough information to compute that displacement |
| 1993 | with what we've read. */ |
| 1994 | |
| 1995 | for (i = 0; i < ehdr2->e_phnum; i++) |
| 1996 | if (phdr2[i].p_type == PT_LOAD) |
| 1997 | { |
| 1998 | Elf64_External_Phdr *phdrp; |
| 1999 | gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| 2000 | CORE_ADDR vaddr, paddr; |
| 2001 | CORE_ADDR displacement_vaddr = 0; |
| 2002 | CORE_ADDR displacement_paddr = 0; |
| 2003 | |
| 2004 | phdrp = &((Elf64_External_Phdr *) buf)[i]; |
| 2005 | buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| 2006 | buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| 2007 | |
| 2008 | vaddr = extract_unsigned_integer (buf_vaddr_p, 8, |
| 2009 | byte_order); |
| 2010 | displacement_vaddr = vaddr - phdr2[i].p_vaddr; |
| 2011 | |
| 2012 | paddr = extract_unsigned_integer (buf_paddr_p, 8, |
| 2013 | byte_order); |
| 2014 | displacement_paddr = paddr - phdr2[i].p_paddr; |
| 2015 | |
| 2016 | if (displacement_vaddr == displacement_paddr) |
| 2017 | displacement = displacement_vaddr; |
| 2018 | |
| 2019 | break; |
| 2020 | } |
| 2021 | |
| 2022 | /* Now compare BUF and BUF2 with optional DISPLACEMENT. */ |
| 2023 | |
| 2024 | for (i = 0; i < phdrs_size / sizeof (Elf64_External_Phdr); i++) |
| 2025 | { |
| 2026 | Elf64_External_Phdr *phdrp; |
| 2027 | Elf64_External_Phdr *phdr2p; |
| 2028 | gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| 2029 | CORE_ADDR vaddr, paddr; |
| 2030 | asection *plt2_asect; |
| 2031 | |
| 2032 | phdrp = &((Elf64_External_Phdr *) buf)[i]; |
| 2033 | buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| 2034 | buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| 2035 | phdr2p = &((Elf64_External_Phdr *) buf2)[i]; |
| 2036 | |
| 2037 | /* PT_GNU_STACK is an exception by being never relocated by |
| 2038 | prelink as its addresses are always zero. */ |
| 2039 | |
| 2040 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 2041 | continue; |
| 2042 | |
| 2043 | /* Check also other adjustment combinations - PR 11786. */ |
| 2044 | |
| 2045 | vaddr = extract_unsigned_integer (buf_vaddr_p, 8, |
| 2046 | byte_order); |
| 2047 | vaddr -= displacement; |
| 2048 | store_unsigned_integer (buf_vaddr_p, 8, byte_order, vaddr); |
| 2049 | |
| 2050 | paddr = extract_unsigned_integer (buf_paddr_p, 8, |
| 2051 | byte_order); |
| 2052 | paddr -= displacement; |
| 2053 | store_unsigned_integer (buf_paddr_p, 8, byte_order, paddr); |
| 2054 | |
| 2055 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 2056 | continue; |
| 2057 | |
| 2058 | /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */ |
| 2059 | plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt"); |
| 2060 | if (plt2_asect) |
| 2061 | { |
| 2062 | int content2; |
| 2063 | gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz; |
| 2064 | CORE_ADDR filesz; |
| 2065 | |
| 2066 | content2 = (bfd_get_section_flags (exec_bfd, plt2_asect) |
| 2067 | & SEC_HAS_CONTENTS) != 0; |
| 2068 | |
| 2069 | filesz = extract_unsigned_integer (buf_filesz_p, 8, |
| 2070 | byte_order); |
| 2071 | |
| 2072 | /* PLT2_ASECT is from on-disk file (exec_bfd) while |
| 2073 | FILESZ is from the in-memory image. */ |
| 2074 | if (content2) |
| 2075 | filesz += bfd_get_section_size (plt2_asect); |
| 2076 | else |
| 2077 | filesz -= bfd_get_section_size (plt2_asect); |
| 2078 | |
| 2079 | store_unsigned_integer (buf_filesz_p, 8, byte_order, |
| 2080 | filesz); |
| 2081 | |
| 2082 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 2083 | continue; |
| 2084 | } |
| 2085 | |
| 2086 | ok = 0; |
| 2087 | break; |
| 2088 | } |
| 2089 | } |
| 2090 | else |
| 2091 | ok = 0; |
| 2092 | } |
| 2093 | |
| 2094 | xfree (buf); |
| 2095 | xfree (buf2); |
| 2096 | |
| 2097 | if (!ok) |
| 2098 | return 0; |
| 2099 | } |
| 2100 | |
| 2101 | if (info_verbose) |
| 2102 | { |
| 2103 | /* It can be printed repeatedly as there is no easy way to check |
| 2104 | the executable symbols/file has been already relocated to |
| 2105 | displacement. */ |
| 2106 | |
| 2107 | printf_unfiltered (_("Using PIE (Position Independent Executable) " |
| 2108 | "displacement %s for \"%s\".\n"), |
| 2109 | paddress (target_gdbarch, displacement), |
| 2110 | bfd_get_filename (exec_bfd)); |
| 2111 | } |
| 2112 | |
| 2113 | *displacementp = displacement; |
| 2114 | return 1; |
| 2115 | } |
| 2116 | |
| 2117 | /* Relocate the main executable. This function should be called upon |
| 2118 | stopping the inferior process at the entry point to the program. |
| 2119 | The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are |
| 2120 | different, the main executable is relocated by the proper amount. */ |
| 2121 | |
| 2122 | static void |
| 2123 | svr4_relocate_main_executable (void) |
| 2124 | { |
| 2125 | CORE_ADDR displacement; |
| 2126 | |
| 2127 | /* If we are re-running this executable, SYMFILE_OBJFILE->SECTION_OFFSETS |
| 2128 | probably contains the offsets computed using the PIE displacement |
| 2129 | from the previous run, which of course are irrelevant for this run. |
| 2130 | So we need to determine the new PIE displacement and recompute the |
| 2131 | section offsets accordingly, even if SYMFILE_OBJFILE->SECTION_OFFSETS |
| 2132 | already contains pre-computed offsets. |
| 2133 | |
| 2134 | If we cannot compute the PIE displacement, either: |
| 2135 | |
| 2136 | - The executable is not PIE. |
| 2137 | |
| 2138 | - SYMFILE_OBJFILE does not match the executable started in the target. |
| 2139 | This can happen for main executable symbols loaded at the host while |
| 2140 | `ld.so --ld-args main-executable' is loaded in the target. |
| 2141 | |
| 2142 | Then we leave the section offsets untouched and use them as is for |
| 2143 | this run. Either: |
| 2144 | |
| 2145 | - These section offsets were properly reset earlier, and thus |
| 2146 | already contain the correct values. This can happen for instance |
| 2147 | when reconnecting via the remote protocol to a target that supports |
| 2148 | the `qOffsets' packet. |
| 2149 | |
| 2150 | - The section offsets were not reset earlier, and the best we can |
| 2151 | hope is that the old offsets are still applicable to the new run. */ |
| 2152 | |
| 2153 | if (! svr4_exec_displacement (&displacement)) |
| 2154 | return; |
| 2155 | |
| 2156 | /* Even DISPLACEMENT 0 is a valid new difference of in-memory vs. in-file |
| 2157 | addresses. */ |
| 2158 | |
| 2159 | if (symfile_objfile) |
| 2160 | { |
| 2161 | struct section_offsets *new_offsets; |
| 2162 | int i; |
| 2163 | |
| 2164 | new_offsets = alloca (symfile_objfile->num_sections |
| 2165 | * sizeof (*new_offsets)); |
| 2166 | |
| 2167 | for (i = 0; i < symfile_objfile->num_sections; i++) |
| 2168 | new_offsets->offsets[i] = displacement; |
| 2169 | |
| 2170 | objfile_relocate (symfile_objfile, new_offsets); |
| 2171 | } |
| 2172 | else if (exec_bfd) |
| 2173 | { |
| 2174 | asection *asect; |
| 2175 | |
| 2176 | for (asect = exec_bfd->sections; asect != NULL; asect = asect->next) |
| 2177 | exec_set_section_address (bfd_get_filename (exec_bfd), asect->index, |
| 2178 | (bfd_section_vma (exec_bfd, asect) |
| 2179 | + displacement)); |
| 2180 | } |
| 2181 | } |
| 2182 | |
| 2183 | /* Implement the "create_inferior_hook" target_solib_ops method. |
| 2184 | |
| 2185 | For SVR4 executables, this first instruction is either the first |
| 2186 | instruction in the dynamic linker (for dynamically linked |
| 2187 | executables) or the instruction at "start" for statically linked |
| 2188 | executables. For dynamically linked executables, the system |
| 2189 | first exec's /lib/libc.so.N, which contains the dynamic linker, |
| 2190 | and starts it running. The dynamic linker maps in any needed |
| 2191 | shared libraries, maps in the actual user executable, and then |
| 2192 | jumps to "start" in the user executable. |
| 2193 | |
| 2194 | We can arrange to cooperate with the dynamic linker to discover the |
| 2195 | names of shared libraries that are dynamically linked, and the base |
| 2196 | addresses to which they are linked. |
| 2197 | |
| 2198 | This function is responsible for discovering those names and |
| 2199 | addresses, and saving sufficient information about them to allow |
| 2200 | their symbols to be read at a later time. |
| 2201 | |
| 2202 | FIXME |
| 2203 | |
| 2204 | Between enable_break() and disable_break(), this code does not |
| 2205 | properly handle hitting breakpoints which the user might have |
| 2206 | set in the startup code or in the dynamic linker itself. Proper |
| 2207 | handling will probably have to wait until the implementation is |
| 2208 | changed to use the "breakpoint handler function" method. |
| 2209 | |
| 2210 | Also, what if child has exit()ed? Must exit loop somehow. */ |
| 2211 | |
| 2212 | static void |
| 2213 | svr4_solib_create_inferior_hook (int from_tty) |
| 2214 | { |
| 2215 | #if defined(_SCO_DS) |
| 2216 | struct inferior *inf; |
| 2217 | struct thread_info *tp; |
| 2218 | #endif /* defined(_SCO_DS) */ |
| 2219 | struct svr4_info *info; |
| 2220 | |
| 2221 | info = get_svr4_info (); |
| 2222 | |
| 2223 | /* Relocate the main executable if necessary. */ |
| 2224 | svr4_relocate_main_executable (); |
| 2225 | |
| 2226 | /* No point setting a breakpoint in the dynamic linker if we can't |
| 2227 | hit it (e.g., a core file, or a trace file). */ |
| 2228 | if (!target_has_execution) |
| 2229 | return; |
| 2230 | |
| 2231 | if (!svr4_have_link_map_offsets ()) |
| 2232 | return; |
| 2233 | |
| 2234 | if (!enable_break (info, from_tty)) |
| 2235 | return; |
| 2236 | |
| 2237 | #if defined(_SCO_DS) |
| 2238 | /* SCO needs the loop below, other systems should be using the |
| 2239 | special shared library breakpoints and the shared library breakpoint |
| 2240 | service routine. |
| 2241 | |
| 2242 | Now run the target. It will eventually hit the breakpoint, at |
| 2243 | which point all of the libraries will have been mapped in and we |
| 2244 | can go groveling around in the dynamic linker structures to find |
| 2245 | out what we need to know about them. */ |
| 2246 | |
| 2247 | inf = current_inferior (); |
| 2248 | tp = inferior_thread (); |
| 2249 | |
| 2250 | clear_proceed_status (); |
| 2251 | inf->control.stop_soon = STOP_QUIETLY; |
| 2252 | tp->suspend.stop_signal = TARGET_SIGNAL_0; |
| 2253 | do |
| 2254 | { |
| 2255 | target_resume (pid_to_ptid (-1), 0, tp->suspend.stop_signal); |
| 2256 | wait_for_inferior (); |
| 2257 | } |
| 2258 | while (tp->suspend.stop_signal != TARGET_SIGNAL_TRAP); |
| 2259 | inf->control.stop_soon = NO_STOP_QUIETLY; |
| 2260 | #endif /* defined(_SCO_DS) */ |
| 2261 | } |
| 2262 | |
| 2263 | static void |
| 2264 | svr4_clear_solib (void) |
| 2265 | { |
| 2266 | struct svr4_info *info; |
| 2267 | |
| 2268 | info = get_svr4_info (); |
| 2269 | info->debug_base = 0; |
| 2270 | info->debug_loader_offset_p = 0; |
| 2271 | info->debug_loader_offset = 0; |
| 2272 | xfree (info->debug_loader_name); |
| 2273 | info->debug_loader_name = NULL; |
| 2274 | } |
| 2275 | |
| 2276 | /* Clear any bits of ADDR that wouldn't fit in a target-format |
| 2277 | data pointer. "Data pointer" here refers to whatever sort of |
| 2278 | address the dynamic linker uses to manage its sections. At the |
| 2279 | moment, we don't support shared libraries on any processors where |
| 2280 | code and data pointers are different sizes. |
| 2281 | |
| 2282 | This isn't really the right solution. What we really need here is |
| 2283 | a way to do arithmetic on CORE_ADDR values that respects the |
| 2284 | natural pointer/address correspondence. (For example, on the MIPS, |
| 2285 | converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to |
| 2286 | sign-extend the value. There, simply truncating the bits above |
| 2287 | gdbarch_ptr_bit, as we do below, is no good.) This should probably |
| 2288 | be a new gdbarch method or something. */ |
| 2289 | static CORE_ADDR |
| 2290 | svr4_truncate_ptr (CORE_ADDR addr) |
| 2291 | { |
| 2292 | if (gdbarch_ptr_bit (target_gdbarch) == sizeof (CORE_ADDR) * 8) |
| 2293 | /* We don't need to truncate anything, and the bit twiddling below |
| 2294 | will fail due to overflow problems. */ |
| 2295 | return addr; |
| 2296 | else |
| 2297 | return addr & (((CORE_ADDR) 1 << gdbarch_ptr_bit (target_gdbarch)) - 1); |
| 2298 | } |
| 2299 | |
| 2300 | |
| 2301 | static void |
| 2302 | svr4_relocate_section_addresses (struct so_list *so, |
| 2303 | struct target_section *sec) |
| 2304 | { |
| 2305 | sec->addr = svr4_truncate_ptr (sec->addr + lm_addr_check (so, |
| 2306 | sec->bfd)); |
| 2307 | sec->endaddr = svr4_truncate_ptr (sec->endaddr + lm_addr_check (so, |
| 2308 | sec->bfd)); |
| 2309 | } |
| 2310 | \f |
| 2311 | |
| 2312 | /* Architecture-specific operations. */ |
| 2313 | |
| 2314 | /* Per-architecture data key. */ |
| 2315 | static struct gdbarch_data *solib_svr4_data; |
| 2316 | |
| 2317 | struct solib_svr4_ops |
| 2318 | { |
| 2319 | /* Return a description of the layout of `struct link_map'. */ |
| 2320 | struct link_map_offsets *(*fetch_link_map_offsets)(void); |
| 2321 | }; |
| 2322 | |
| 2323 | /* Return a default for the architecture-specific operations. */ |
| 2324 | |
| 2325 | static void * |
| 2326 | solib_svr4_init (struct obstack *obstack) |
| 2327 | { |
| 2328 | struct solib_svr4_ops *ops; |
| 2329 | |
| 2330 | ops = OBSTACK_ZALLOC (obstack, struct solib_svr4_ops); |
| 2331 | ops->fetch_link_map_offsets = NULL; |
| 2332 | return ops; |
| 2333 | } |
| 2334 | |
| 2335 | /* Set the architecture-specific `struct link_map_offsets' fetcher for |
| 2336 | GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */ |
| 2337 | |
| 2338 | void |
| 2339 | set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch, |
| 2340 | struct link_map_offsets *(*flmo) (void)) |
| 2341 | { |
| 2342 | struct solib_svr4_ops *ops = gdbarch_data (gdbarch, solib_svr4_data); |
| 2343 | |
| 2344 | ops->fetch_link_map_offsets = flmo; |
| 2345 | |
| 2346 | set_solib_ops (gdbarch, &svr4_so_ops); |
| 2347 | } |
| 2348 | |
| 2349 | /* Fetch a link_map_offsets structure using the architecture-specific |
| 2350 | `struct link_map_offsets' fetcher. */ |
| 2351 | |
| 2352 | static struct link_map_offsets * |
| 2353 | svr4_fetch_link_map_offsets (void) |
| 2354 | { |
| 2355 | struct solib_svr4_ops *ops = gdbarch_data (target_gdbarch, solib_svr4_data); |
| 2356 | |
| 2357 | gdb_assert (ops->fetch_link_map_offsets); |
| 2358 | return ops->fetch_link_map_offsets (); |
| 2359 | } |
| 2360 | |
| 2361 | /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */ |
| 2362 | |
| 2363 | static int |
| 2364 | svr4_have_link_map_offsets (void) |
| 2365 | { |
| 2366 | struct solib_svr4_ops *ops = gdbarch_data (target_gdbarch, solib_svr4_data); |
| 2367 | |
| 2368 | return (ops->fetch_link_map_offsets != NULL); |
| 2369 | } |
| 2370 | \f |
| 2371 | |
| 2372 | /* Most OS'es that have SVR4-style ELF dynamic libraries define a |
| 2373 | `struct r_debug' and a `struct link_map' that are binary compatible |
| 2374 | with the origional SVR4 implementation. */ |
| 2375 | |
| 2376 | /* Fetch (and possibly build) an appropriate `struct link_map_offsets' |
| 2377 | for an ILP32 SVR4 system. */ |
| 2378 | |
| 2379 | struct link_map_offsets * |
| 2380 | svr4_ilp32_fetch_link_map_offsets (void) |
| 2381 | { |
| 2382 | static struct link_map_offsets lmo; |
| 2383 | static struct link_map_offsets *lmp = NULL; |
| 2384 | |
| 2385 | if (lmp == NULL) |
| 2386 | { |
| 2387 | lmp = &lmo; |
| 2388 | |
| 2389 | lmo.r_version_offset = 0; |
| 2390 | lmo.r_version_size = 4; |
| 2391 | lmo.r_map_offset = 4; |
| 2392 | lmo.r_brk_offset = 8; |
| 2393 | lmo.r_ldsomap_offset = 20; |
| 2394 | |
| 2395 | /* Everything we need is in the first 20 bytes. */ |
| 2396 | lmo.link_map_size = 20; |
| 2397 | lmo.l_addr_offset = 0; |
| 2398 | lmo.l_name_offset = 4; |
| 2399 | lmo.l_ld_offset = 8; |
| 2400 | lmo.l_next_offset = 12; |
| 2401 | lmo.l_prev_offset = 16; |
| 2402 | } |
| 2403 | |
| 2404 | return lmp; |
| 2405 | } |
| 2406 | |
| 2407 | /* Fetch (and possibly build) an appropriate `struct link_map_offsets' |
| 2408 | for an LP64 SVR4 system. */ |
| 2409 | |
| 2410 | struct link_map_offsets * |
| 2411 | svr4_lp64_fetch_link_map_offsets (void) |
| 2412 | { |
| 2413 | static struct link_map_offsets lmo; |
| 2414 | static struct link_map_offsets *lmp = NULL; |
| 2415 | |
| 2416 | if (lmp == NULL) |
| 2417 | { |
| 2418 | lmp = &lmo; |
| 2419 | |
| 2420 | lmo.r_version_offset = 0; |
| 2421 | lmo.r_version_size = 4; |
| 2422 | lmo.r_map_offset = 8; |
| 2423 | lmo.r_brk_offset = 16; |
| 2424 | lmo.r_ldsomap_offset = 40; |
| 2425 | |
| 2426 | /* Everything we need is in the first 40 bytes. */ |
| 2427 | lmo.link_map_size = 40; |
| 2428 | lmo.l_addr_offset = 0; |
| 2429 | lmo.l_name_offset = 8; |
| 2430 | lmo.l_ld_offset = 16; |
| 2431 | lmo.l_next_offset = 24; |
| 2432 | lmo.l_prev_offset = 32; |
| 2433 | } |
| 2434 | |
| 2435 | return lmp; |
| 2436 | } |
| 2437 | \f |
| 2438 | |
| 2439 | struct target_so_ops svr4_so_ops; |
| 2440 | |
| 2441 | /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a |
| 2442 | different rule for symbol lookup. The lookup begins here in the DSO, not in |
| 2443 | the main executable. */ |
| 2444 | |
| 2445 | static struct symbol * |
| 2446 | elf_lookup_lib_symbol (const struct objfile *objfile, |
| 2447 | const char *name, |
| 2448 | const domain_enum domain) |
| 2449 | { |
| 2450 | bfd *abfd; |
| 2451 | |
| 2452 | if (objfile == symfile_objfile) |
| 2453 | abfd = exec_bfd; |
| 2454 | else |
| 2455 | { |
| 2456 | /* OBJFILE should have been passed as the non-debug one. */ |
| 2457 | gdb_assert (objfile->separate_debug_objfile_backlink == NULL); |
| 2458 | |
| 2459 | abfd = objfile->obfd; |
| 2460 | } |
| 2461 | |
| 2462 | if (abfd == NULL || scan_dyntag (DT_SYMBOLIC, abfd, NULL) != 1) |
| 2463 | return NULL; |
| 2464 | |
| 2465 | return lookup_global_symbol_from_objfile (objfile, name, domain); |
| 2466 | } |
| 2467 | |
| 2468 | extern initialize_file_ftype _initialize_svr4_solib; /* -Wmissing-prototypes */ |
| 2469 | |
| 2470 | void |
| 2471 | _initialize_svr4_solib (void) |
| 2472 | { |
| 2473 | solib_svr4_data = gdbarch_data_register_pre_init (solib_svr4_init); |
| 2474 | solib_svr4_pspace_data |
| 2475 | = register_program_space_data_with_cleanup (svr4_pspace_data_cleanup); |
| 2476 | |
| 2477 | svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses; |
| 2478 | svr4_so_ops.free_so = svr4_free_so; |
| 2479 | svr4_so_ops.clear_solib = svr4_clear_solib; |
| 2480 | svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook; |
| 2481 | svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling; |
| 2482 | svr4_so_ops.current_sos = svr4_current_sos; |
| 2483 | svr4_so_ops.open_symbol_file_object = open_symbol_file_object; |
| 2484 | svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code; |
| 2485 | svr4_so_ops.bfd_open = solib_bfd_open; |
| 2486 | svr4_so_ops.lookup_lib_global_symbol = elf_lookup_lib_symbol; |
| 2487 | svr4_so_ops.same = svr4_same; |
| 2488 | svr4_so_ops.keep_data_in_core = svr4_keep_data_in_core; |
| 2489 | } |