| 1 | /* Handle SVR4 shared libraries for GDB, the GNU Debugger. |
| 2 | |
| 3 | Copyright (C) 1990-2021 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | |
| 22 | #include "elf/external.h" |
| 23 | #include "elf/common.h" |
| 24 | #include "elf/mips.h" |
| 25 | |
| 26 | #include "symtab.h" |
| 27 | #include "bfd.h" |
| 28 | #include "symfile.h" |
| 29 | #include "objfiles.h" |
| 30 | #include "gdbcore.h" |
| 31 | #include "target.h" |
| 32 | #include "inferior.h" |
| 33 | #include "infrun.h" |
| 34 | #include "regcache.h" |
| 35 | #include "gdbthread.h" |
| 36 | #include "observable.h" |
| 37 | |
| 38 | #include "solist.h" |
| 39 | #include "solib.h" |
| 40 | #include "solib-svr4.h" |
| 41 | |
| 42 | #include "bfd-target.h" |
| 43 | #include "elf-bfd.h" |
| 44 | #include "exec.h" |
| 45 | #include "auxv.h" |
| 46 | #include "gdb_bfd.h" |
| 47 | #include "probe.h" |
| 48 | |
| 49 | static struct link_map_offsets *svr4_fetch_link_map_offsets (void); |
| 50 | static int svr4_have_link_map_offsets (void); |
| 51 | static void svr4_relocate_main_executable (void); |
| 52 | static void svr4_free_library_list (void *p_list); |
| 53 | static void probes_table_remove_objfile_probes (struct objfile *objfile); |
| 54 | static void svr4_iterate_over_objfiles_in_search_order ( |
| 55 | struct gdbarch *gdbarch, iterate_over_objfiles_in_search_order_cb_ftype *cb, |
| 56 | void *cb_data, struct objfile *objfile); |
| 57 | |
| 58 | |
| 59 | /* On SVR4 systems, a list of symbols in the dynamic linker where |
| 60 | GDB can try to place a breakpoint to monitor shared library |
| 61 | events. |
| 62 | |
| 63 | If none of these symbols are found, or other errors occur, then |
| 64 | SVR4 systems will fall back to using a symbol as the "startup |
| 65 | mapping complete" breakpoint address. */ |
| 66 | |
| 67 | static const char * const solib_break_names[] = |
| 68 | { |
| 69 | "r_debug_state", |
| 70 | "_r_debug_state", |
| 71 | "_dl_debug_state", |
| 72 | "rtld_db_dlactivity", |
| 73 | "__dl_rtld_db_dlactivity", |
| 74 | "_rtld_debug_state", |
| 75 | |
| 76 | NULL |
| 77 | }; |
| 78 | |
| 79 | static const char * const bkpt_names[] = |
| 80 | { |
| 81 | "_start", |
| 82 | "__start", |
| 83 | "main", |
| 84 | NULL |
| 85 | }; |
| 86 | |
| 87 | static const char * const main_name_list[] = |
| 88 | { |
| 89 | "main_$main", |
| 90 | NULL |
| 91 | }; |
| 92 | |
| 93 | /* What to do when a probe stop occurs. */ |
| 94 | |
| 95 | enum probe_action |
| 96 | { |
| 97 | /* Something went seriously wrong. Stop using probes and |
| 98 | revert to using the older interface. */ |
| 99 | PROBES_INTERFACE_FAILED, |
| 100 | |
| 101 | /* No action is required. The shared object list is still |
| 102 | valid. */ |
| 103 | DO_NOTHING, |
| 104 | |
| 105 | /* The shared object list should be reloaded entirely. */ |
| 106 | FULL_RELOAD, |
| 107 | |
| 108 | /* Attempt to incrementally update the shared object list. If |
| 109 | the update fails or is not possible, fall back to reloading |
| 110 | the list in full. */ |
| 111 | UPDATE_OR_RELOAD, |
| 112 | }; |
| 113 | |
| 114 | /* A probe's name and its associated action. */ |
| 115 | |
| 116 | struct probe_info |
| 117 | { |
| 118 | /* The name of the probe. */ |
| 119 | const char *name; |
| 120 | |
| 121 | /* What to do when a probe stop occurs. */ |
| 122 | enum probe_action action; |
| 123 | }; |
| 124 | |
| 125 | /* A list of named probes and their associated actions. If all |
| 126 | probes are present in the dynamic linker then the probes-based |
| 127 | interface will be used. */ |
| 128 | |
| 129 | static const struct probe_info probe_info[] = |
| 130 | { |
| 131 | { "init_start", DO_NOTHING }, |
| 132 | { "init_complete", FULL_RELOAD }, |
| 133 | { "map_start", DO_NOTHING }, |
| 134 | { "map_failed", DO_NOTHING }, |
| 135 | { "reloc_complete", UPDATE_OR_RELOAD }, |
| 136 | { "unmap_start", DO_NOTHING }, |
| 137 | { "unmap_complete", FULL_RELOAD }, |
| 138 | }; |
| 139 | |
| 140 | #define NUM_PROBES ARRAY_SIZE (probe_info) |
| 141 | |
| 142 | /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent |
| 143 | the same shared library. */ |
| 144 | |
| 145 | static int |
| 146 | svr4_same_1 (const char *gdb_so_name, const char *inferior_so_name) |
| 147 | { |
| 148 | if (strcmp (gdb_so_name, inferior_so_name) == 0) |
| 149 | return 1; |
| 150 | |
| 151 | /* On Solaris, when starting inferior we think that dynamic linker is |
| 152 | /usr/lib/ld.so.1, but later on, the table of loaded shared libraries |
| 153 | contains /lib/ld.so.1. Sometimes one file is a link to another, but |
| 154 | sometimes they have identical content, but are not linked to each |
| 155 | other. We don't restrict this check for Solaris, but the chances |
| 156 | of running into this situation elsewhere are very low. */ |
| 157 | if (strcmp (gdb_so_name, "/usr/lib/ld.so.1") == 0 |
| 158 | && strcmp (inferior_so_name, "/lib/ld.so.1") == 0) |
| 159 | return 1; |
| 160 | |
| 161 | /* Similarly, we observed the same issue with amd64 and sparcv9, but with |
| 162 | different locations. */ |
| 163 | if (strcmp (gdb_so_name, "/usr/lib/amd64/ld.so.1") == 0 |
| 164 | && strcmp (inferior_so_name, "/lib/amd64/ld.so.1") == 0) |
| 165 | return 1; |
| 166 | |
| 167 | if (strcmp (gdb_so_name, "/usr/lib/sparcv9/ld.so.1") == 0 |
| 168 | && strcmp (inferior_so_name, "/lib/sparcv9/ld.so.1") == 0) |
| 169 | return 1; |
| 170 | |
| 171 | return 0; |
| 172 | } |
| 173 | |
| 174 | static int |
| 175 | svr4_same (struct so_list *gdb, struct so_list *inferior) |
| 176 | { |
| 177 | return (svr4_same_1 (gdb->so_original_name, inferior->so_original_name)); |
| 178 | } |
| 179 | |
| 180 | static std::unique_ptr<lm_info_svr4> |
| 181 | lm_info_read (CORE_ADDR lm_addr) |
| 182 | { |
| 183 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 184 | std::unique_ptr<lm_info_svr4> lm_info; |
| 185 | |
| 186 | gdb::byte_vector lm (lmo->link_map_size); |
| 187 | |
| 188 | if (target_read_memory (lm_addr, lm.data (), lmo->link_map_size) != 0) |
| 189 | warning (_("Error reading shared library list entry at %s"), |
| 190 | paddress (target_gdbarch (), lm_addr)); |
| 191 | else |
| 192 | { |
| 193 | struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| 194 | |
| 195 | lm_info.reset (new lm_info_svr4); |
| 196 | lm_info->lm_addr = lm_addr; |
| 197 | |
| 198 | lm_info->l_addr_inferior = extract_typed_address (&lm[lmo->l_addr_offset], |
| 199 | ptr_type); |
| 200 | lm_info->l_ld = extract_typed_address (&lm[lmo->l_ld_offset], ptr_type); |
| 201 | lm_info->l_next = extract_typed_address (&lm[lmo->l_next_offset], |
| 202 | ptr_type); |
| 203 | lm_info->l_prev = extract_typed_address (&lm[lmo->l_prev_offset], |
| 204 | ptr_type); |
| 205 | lm_info->l_name = extract_typed_address (&lm[lmo->l_name_offset], |
| 206 | ptr_type); |
| 207 | } |
| 208 | |
| 209 | return lm_info; |
| 210 | } |
| 211 | |
| 212 | static int |
| 213 | has_lm_dynamic_from_link_map (void) |
| 214 | { |
| 215 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 216 | |
| 217 | return lmo->l_ld_offset >= 0; |
| 218 | } |
| 219 | |
| 220 | static CORE_ADDR |
| 221 | lm_addr_check (const struct so_list *so, bfd *abfd) |
| 222 | { |
| 223 | lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info; |
| 224 | |
| 225 | if (!li->l_addr_p) |
| 226 | { |
| 227 | struct bfd_section *dyninfo_sect; |
| 228 | CORE_ADDR l_addr, l_dynaddr, dynaddr; |
| 229 | |
| 230 | l_addr = li->l_addr_inferior; |
| 231 | |
| 232 | if (! abfd || ! has_lm_dynamic_from_link_map ()) |
| 233 | goto set_addr; |
| 234 | |
| 235 | l_dynaddr = li->l_ld; |
| 236 | |
| 237 | dyninfo_sect = bfd_get_section_by_name (abfd, ".dynamic"); |
| 238 | if (dyninfo_sect == NULL) |
| 239 | goto set_addr; |
| 240 | |
| 241 | dynaddr = bfd_section_vma (dyninfo_sect); |
| 242 | |
| 243 | if (dynaddr + l_addr != l_dynaddr) |
| 244 | { |
| 245 | CORE_ADDR align = 0x1000; |
| 246 | CORE_ADDR minpagesize = align; |
| 247 | |
| 248 | if (bfd_get_flavour (abfd) == bfd_target_elf_flavour) |
| 249 | { |
| 250 | Elf_Internal_Ehdr *ehdr = elf_tdata (abfd)->elf_header; |
| 251 | Elf_Internal_Phdr *phdr = elf_tdata (abfd)->phdr; |
| 252 | int i; |
| 253 | |
| 254 | align = 1; |
| 255 | |
| 256 | for (i = 0; i < ehdr->e_phnum; i++) |
| 257 | if (phdr[i].p_type == PT_LOAD && phdr[i].p_align > align) |
| 258 | align = phdr[i].p_align; |
| 259 | |
| 260 | minpagesize = get_elf_backend_data (abfd)->minpagesize; |
| 261 | } |
| 262 | |
| 263 | /* Turn it into a mask. */ |
| 264 | align--; |
| 265 | |
| 266 | /* If the changes match the alignment requirements, we |
| 267 | assume we're using a core file that was generated by the |
| 268 | same binary, just prelinked with a different base offset. |
| 269 | If it doesn't match, we may have a different binary, the |
| 270 | same binary with the dynamic table loaded at an unrelated |
| 271 | location, or anything, really. To avoid regressions, |
| 272 | don't adjust the base offset in the latter case, although |
| 273 | odds are that, if things really changed, debugging won't |
| 274 | quite work. |
| 275 | |
| 276 | One could expect more the condition |
| 277 | ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0) |
| 278 | but the one below is relaxed for PPC. The PPC kernel supports |
| 279 | either 4k or 64k page sizes. To be prepared for 64k pages, |
| 280 | PPC ELF files are built using an alignment requirement of 64k. |
| 281 | However, when running on a kernel supporting 4k pages, the memory |
| 282 | mapping of the library may not actually happen on a 64k boundary! |
| 283 | |
| 284 | (In the usual case where (l_addr & align) == 0, this check is |
| 285 | equivalent to the possibly expected check above.) |
| 286 | |
| 287 | Even on PPC it must be zero-aligned at least for MINPAGESIZE. */ |
| 288 | |
| 289 | l_addr = l_dynaddr - dynaddr; |
| 290 | |
| 291 | if ((l_addr & (minpagesize - 1)) == 0 |
| 292 | && (l_addr & align) == ((l_dynaddr - dynaddr) & align)) |
| 293 | { |
| 294 | if (info_verbose) |
| 295 | printf_unfiltered (_("Using PIC (Position Independent Code) " |
| 296 | "prelink displacement %s for \"%s\".\n"), |
| 297 | paddress (target_gdbarch (), l_addr), |
| 298 | so->so_name); |
| 299 | } |
| 300 | else |
| 301 | { |
| 302 | /* There is no way to verify the library file matches. prelink |
| 303 | can during prelinking of an unprelinked file (or unprelinking |
| 304 | of a prelinked file) shift the DYNAMIC segment by arbitrary |
| 305 | offset without any page size alignment. There is no way to |
| 306 | find out the ELF header and/or Program Headers for a limited |
| 307 | verification if it they match. One could do a verification |
| 308 | of the DYNAMIC segment. Still the found address is the best |
| 309 | one GDB could find. */ |
| 310 | |
| 311 | warning (_(".dynamic section for \"%s\" " |
| 312 | "is not at the expected address " |
| 313 | "(wrong library or version mismatch?)"), so->so_name); |
| 314 | } |
| 315 | } |
| 316 | |
| 317 | set_addr: |
| 318 | li->l_addr = l_addr; |
| 319 | li->l_addr_p = 1; |
| 320 | } |
| 321 | |
| 322 | return li->l_addr; |
| 323 | } |
| 324 | |
| 325 | /* Per pspace SVR4 specific data. */ |
| 326 | |
| 327 | struct svr4_info |
| 328 | { |
| 329 | svr4_info () = default; |
| 330 | ~svr4_info (); |
| 331 | |
| 332 | /* Base of dynamic linker structures. */ |
| 333 | CORE_ADDR debug_base = 0; |
| 334 | |
| 335 | /* Validity flag for debug_loader_offset. */ |
| 336 | int debug_loader_offset_p = 0; |
| 337 | |
| 338 | /* Load address for the dynamic linker, inferred. */ |
| 339 | CORE_ADDR debug_loader_offset = 0; |
| 340 | |
| 341 | /* Name of the dynamic linker, valid if debug_loader_offset_p. */ |
| 342 | char *debug_loader_name = nullptr; |
| 343 | |
| 344 | /* Load map address for the main executable. */ |
| 345 | CORE_ADDR main_lm_addr = 0; |
| 346 | |
| 347 | CORE_ADDR interp_text_sect_low = 0; |
| 348 | CORE_ADDR interp_text_sect_high = 0; |
| 349 | CORE_ADDR interp_plt_sect_low = 0; |
| 350 | CORE_ADDR interp_plt_sect_high = 0; |
| 351 | |
| 352 | /* Nonzero if the list of objects was last obtained from the target |
| 353 | via qXfer:libraries-svr4:read. */ |
| 354 | int using_xfer = 0; |
| 355 | |
| 356 | /* Table of struct probe_and_action instances, used by the |
| 357 | probes-based interface to map breakpoint addresses to probes |
| 358 | and their associated actions. Lookup is performed using |
| 359 | probe_and_action->prob->address. */ |
| 360 | htab_up probes_table; |
| 361 | |
| 362 | /* List of objects loaded into the inferior, used by the probes- |
| 363 | based interface. */ |
| 364 | struct so_list *solib_list = nullptr; |
| 365 | }; |
| 366 | |
| 367 | /* Per-program-space data key. */ |
| 368 | static const struct program_space_key<svr4_info> solib_svr4_pspace_data; |
| 369 | |
| 370 | /* Free the probes table. */ |
| 371 | |
| 372 | static void |
| 373 | free_probes_table (struct svr4_info *info) |
| 374 | { |
| 375 | info->probes_table.reset (nullptr); |
| 376 | } |
| 377 | |
| 378 | /* Free the solib list. */ |
| 379 | |
| 380 | static void |
| 381 | free_solib_list (struct svr4_info *info) |
| 382 | { |
| 383 | svr4_free_library_list (&info->solib_list); |
| 384 | info->solib_list = NULL; |
| 385 | } |
| 386 | |
| 387 | svr4_info::~svr4_info () |
| 388 | { |
| 389 | free_solib_list (this); |
| 390 | } |
| 391 | |
| 392 | /* Get the svr4 data for program space PSPACE. If none is found yet, add it now. |
| 393 | This function always returns a valid object. */ |
| 394 | |
| 395 | static struct svr4_info * |
| 396 | get_svr4_info (program_space *pspace) |
| 397 | { |
| 398 | struct svr4_info *info = solib_svr4_pspace_data.get (pspace); |
| 399 | |
| 400 | if (info == NULL) |
| 401 | info = solib_svr4_pspace_data.emplace (pspace); |
| 402 | |
| 403 | return info; |
| 404 | } |
| 405 | |
| 406 | /* Local function prototypes */ |
| 407 | |
| 408 | static int match_main (const char *); |
| 409 | |
| 410 | /* Read program header TYPE from inferior memory. The header is found |
| 411 | by scanning the OS auxiliary vector. |
| 412 | |
| 413 | If TYPE == -1, return the program headers instead of the contents of |
| 414 | one program header. |
| 415 | |
| 416 | Return vector of bytes holding the program header contents, or an empty |
| 417 | optional on failure. If successful and P_ARCH_SIZE is non-NULL, the target |
| 418 | architecture size (32-bit or 64-bit) is returned to *P_ARCH_SIZE. Likewise, |
| 419 | the base address of the section is returned in *BASE_ADDR. */ |
| 420 | |
| 421 | static gdb::optional<gdb::byte_vector> |
| 422 | read_program_header (int type, int *p_arch_size, CORE_ADDR *base_addr) |
| 423 | { |
| 424 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| 425 | CORE_ADDR at_phdr, at_phent, at_phnum, pt_phdr = 0; |
| 426 | int arch_size, sect_size; |
| 427 | CORE_ADDR sect_addr; |
| 428 | int pt_phdr_p = 0; |
| 429 | |
| 430 | /* Get required auxv elements from target. */ |
| 431 | if (target_auxv_search (current_top_target (), AT_PHDR, &at_phdr) <= 0) |
| 432 | return {}; |
| 433 | if (target_auxv_search (current_top_target (), AT_PHENT, &at_phent) <= 0) |
| 434 | return {}; |
| 435 | if (target_auxv_search (current_top_target (), AT_PHNUM, &at_phnum) <= 0) |
| 436 | return {}; |
| 437 | if (!at_phdr || !at_phnum) |
| 438 | return {}; |
| 439 | |
| 440 | /* Determine ELF architecture type. */ |
| 441 | if (at_phent == sizeof (Elf32_External_Phdr)) |
| 442 | arch_size = 32; |
| 443 | else if (at_phent == sizeof (Elf64_External_Phdr)) |
| 444 | arch_size = 64; |
| 445 | else |
| 446 | return {}; |
| 447 | |
| 448 | /* Find the requested segment. */ |
| 449 | if (type == -1) |
| 450 | { |
| 451 | sect_addr = at_phdr; |
| 452 | sect_size = at_phent * at_phnum; |
| 453 | } |
| 454 | else if (arch_size == 32) |
| 455 | { |
| 456 | Elf32_External_Phdr phdr; |
| 457 | int i; |
| 458 | |
| 459 | /* Search for requested PHDR. */ |
| 460 | for (i = 0; i < at_phnum; i++) |
| 461 | { |
| 462 | int p_type; |
| 463 | |
| 464 | if (target_read_memory (at_phdr + i * sizeof (phdr), |
| 465 | (gdb_byte *)&phdr, sizeof (phdr))) |
| 466 | return {}; |
| 467 | |
| 468 | p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type, |
| 469 | 4, byte_order); |
| 470 | |
| 471 | if (p_type == PT_PHDR) |
| 472 | { |
| 473 | pt_phdr_p = 1; |
| 474 | pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr, |
| 475 | 4, byte_order); |
| 476 | } |
| 477 | |
| 478 | if (p_type == type) |
| 479 | break; |
| 480 | } |
| 481 | |
| 482 | if (i == at_phnum) |
| 483 | return {}; |
| 484 | |
| 485 | /* Retrieve address and size. */ |
| 486 | sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr, |
| 487 | 4, byte_order); |
| 488 | sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz, |
| 489 | 4, byte_order); |
| 490 | } |
| 491 | else |
| 492 | { |
| 493 | Elf64_External_Phdr phdr; |
| 494 | int i; |
| 495 | |
| 496 | /* Search for requested PHDR. */ |
| 497 | for (i = 0; i < at_phnum; i++) |
| 498 | { |
| 499 | int p_type; |
| 500 | |
| 501 | if (target_read_memory (at_phdr + i * sizeof (phdr), |
| 502 | (gdb_byte *)&phdr, sizeof (phdr))) |
| 503 | return {}; |
| 504 | |
| 505 | p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type, |
| 506 | 4, byte_order); |
| 507 | |
| 508 | if (p_type == PT_PHDR) |
| 509 | { |
| 510 | pt_phdr_p = 1; |
| 511 | pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr, |
| 512 | 8, byte_order); |
| 513 | } |
| 514 | |
| 515 | if (p_type == type) |
| 516 | break; |
| 517 | } |
| 518 | |
| 519 | if (i == at_phnum) |
| 520 | return {}; |
| 521 | |
| 522 | /* Retrieve address and size. */ |
| 523 | sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr, |
| 524 | 8, byte_order); |
| 525 | sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz, |
| 526 | 8, byte_order); |
| 527 | } |
| 528 | |
| 529 | /* PT_PHDR is optional, but we really need it |
| 530 | for PIE to make this work in general. */ |
| 531 | |
| 532 | if (pt_phdr_p) |
| 533 | { |
| 534 | /* at_phdr is real address in memory. pt_phdr is what pheader says it is. |
| 535 | Relocation offset is the difference between the two. */ |
| 536 | sect_addr = sect_addr + (at_phdr - pt_phdr); |
| 537 | } |
| 538 | |
| 539 | /* Read in requested program header. */ |
| 540 | gdb::byte_vector buf (sect_size); |
| 541 | if (target_read_memory (sect_addr, buf.data (), sect_size)) |
| 542 | return {}; |
| 543 | |
| 544 | if (p_arch_size) |
| 545 | *p_arch_size = arch_size; |
| 546 | if (base_addr) |
| 547 | *base_addr = sect_addr; |
| 548 | |
| 549 | return buf; |
| 550 | } |
| 551 | |
| 552 | |
| 553 | /* Return program interpreter string. */ |
| 554 | static gdb::optional<gdb::byte_vector> |
| 555 | find_program_interpreter (void) |
| 556 | { |
| 557 | /* If we have a current exec_bfd, use its section table. */ |
| 558 | if (current_program_space->exec_bfd () |
| 559 | && (bfd_get_flavour (current_program_space->exec_bfd ()) |
| 560 | == bfd_target_elf_flavour)) |
| 561 | { |
| 562 | struct bfd_section *interp_sect; |
| 563 | |
| 564 | interp_sect = bfd_get_section_by_name (current_program_space->exec_bfd (), |
| 565 | ".interp"); |
| 566 | if (interp_sect != NULL) |
| 567 | { |
| 568 | int sect_size = bfd_section_size (interp_sect); |
| 569 | |
| 570 | gdb::byte_vector buf (sect_size); |
| 571 | bfd_get_section_contents (current_program_space->exec_bfd (), |
| 572 | interp_sect, buf.data (), 0, sect_size); |
| 573 | return buf; |
| 574 | } |
| 575 | } |
| 576 | |
| 577 | /* If we didn't find it, use the target auxiliary vector. */ |
| 578 | return read_program_header (PT_INTERP, NULL, NULL); |
| 579 | } |
| 580 | |
| 581 | |
| 582 | /* Scan for DESIRED_DYNTAG in .dynamic section of ABFD. If DESIRED_DYNTAG is |
| 583 | found, 1 is returned and the corresponding PTR is set. */ |
| 584 | |
| 585 | static int |
| 586 | scan_dyntag (const int desired_dyntag, bfd *abfd, CORE_ADDR *ptr, |
| 587 | CORE_ADDR *ptr_addr) |
| 588 | { |
| 589 | int arch_size, step, sect_size; |
| 590 | long current_dyntag; |
| 591 | CORE_ADDR dyn_ptr, dyn_addr; |
| 592 | gdb_byte *bufend, *bufstart, *buf; |
| 593 | Elf32_External_Dyn *x_dynp_32; |
| 594 | Elf64_External_Dyn *x_dynp_64; |
| 595 | struct bfd_section *sect; |
| 596 | |
| 597 | if (abfd == NULL) |
| 598 | return 0; |
| 599 | |
| 600 | if (bfd_get_flavour (abfd) != bfd_target_elf_flavour) |
| 601 | return 0; |
| 602 | |
| 603 | arch_size = bfd_get_arch_size (abfd); |
| 604 | if (arch_size == -1) |
| 605 | return 0; |
| 606 | |
| 607 | /* Find the start address of the .dynamic section. */ |
| 608 | sect = bfd_get_section_by_name (abfd, ".dynamic"); |
| 609 | if (sect == NULL) |
| 610 | return 0; |
| 611 | |
| 612 | bool found = false; |
| 613 | for (const target_section &target_section |
| 614 | : current_program_space->target_sections ()) |
| 615 | if (sect == target_section.the_bfd_section) |
| 616 | { |
| 617 | dyn_addr = target_section.addr; |
| 618 | found = true; |
| 619 | break; |
| 620 | } |
| 621 | if (!found) |
| 622 | { |
| 623 | /* ABFD may come from OBJFILE acting only as a symbol file without being |
| 624 | loaded into the target (see add_symbol_file_command). This case is |
| 625 | such fallback to the file VMA address without the possibility of |
| 626 | having the section relocated to its actual in-memory address. */ |
| 627 | |
| 628 | dyn_addr = bfd_section_vma (sect); |
| 629 | } |
| 630 | |
| 631 | /* Read in .dynamic from the BFD. We will get the actual value |
| 632 | from memory later. */ |
| 633 | sect_size = bfd_section_size (sect); |
| 634 | buf = bufstart = (gdb_byte *) alloca (sect_size); |
| 635 | if (!bfd_get_section_contents (abfd, sect, |
| 636 | buf, 0, sect_size)) |
| 637 | return 0; |
| 638 | |
| 639 | /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */ |
| 640 | step = (arch_size == 32) ? sizeof (Elf32_External_Dyn) |
| 641 | : sizeof (Elf64_External_Dyn); |
| 642 | for (bufend = buf + sect_size; |
| 643 | buf < bufend; |
| 644 | buf += step) |
| 645 | { |
| 646 | if (arch_size == 32) |
| 647 | { |
| 648 | x_dynp_32 = (Elf32_External_Dyn *) buf; |
| 649 | current_dyntag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_tag); |
| 650 | dyn_ptr = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_un.d_ptr); |
| 651 | } |
| 652 | else |
| 653 | { |
| 654 | x_dynp_64 = (Elf64_External_Dyn *) buf; |
| 655 | current_dyntag = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_tag); |
| 656 | dyn_ptr = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_un.d_ptr); |
| 657 | } |
| 658 | if (current_dyntag == DT_NULL) |
| 659 | return 0; |
| 660 | if (current_dyntag == desired_dyntag) |
| 661 | { |
| 662 | /* If requested, try to read the runtime value of this .dynamic |
| 663 | entry. */ |
| 664 | if (ptr) |
| 665 | { |
| 666 | struct type *ptr_type; |
| 667 | gdb_byte ptr_buf[8]; |
| 668 | CORE_ADDR ptr_addr_1; |
| 669 | |
| 670 | ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| 671 | ptr_addr_1 = dyn_addr + (buf - bufstart) + arch_size / 8; |
| 672 | if (target_read_memory (ptr_addr_1, ptr_buf, arch_size / 8) == 0) |
| 673 | dyn_ptr = extract_typed_address (ptr_buf, ptr_type); |
| 674 | *ptr = dyn_ptr; |
| 675 | if (ptr_addr) |
| 676 | *ptr_addr = dyn_addr + (buf - bufstart); |
| 677 | } |
| 678 | return 1; |
| 679 | } |
| 680 | } |
| 681 | |
| 682 | return 0; |
| 683 | } |
| 684 | |
| 685 | /* Scan for DESIRED_DYNTAG in .dynamic section of the target's main executable, |
| 686 | found by consulting the OS auxillary vector. If DESIRED_DYNTAG is found, 1 |
| 687 | is returned and the corresponding PTR is set. */ |
| 688 | |
| 689 | static int |
| 690 | scan_dyntag_auxv (const int desired_dyntag, CORE_ADDR *ptr, |
| 691 | CORE_ADDR *ptr_addr) |
| 692 | { |
| 693 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| 694 | int arch_size, step; |
| 695 | long current_dyntag; |
| 696 | CORE_ADDR dyn_ptr; |
| 697 | CORE_ADDR base_addr; |
| 698 | |
| 699 | /* Read in .dynamic section. */ |
| 700 | gdb::optional<gdb::byte_vector> ph_data |
| 701 | = read_program_header (PT_DYNAMIC, &arch_size, &base_addr); |
| 702 | if (!ph_data) |
| 703 | return 0; |
| 704 | |
| 705 | /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */ |
| 706 | step = (arch_size == 32) ? sizeof (Elf32_External_Dyn) |
| 707 | : sizeof (Elf64_External_Dyn); |
| 708 | for (gdb_byte *buf = ph_data->data (), *bufend = buf + ph_data->size (); |
| 709 | buf < bufend; buf += step) |
| 710 | { |
| 711 | if (arch_size == 32) |
| 712 | { |
| 713 | Elf32_External_Dyn *dynp = (Elf32_External_Dyn *) buf; |
| 714 | |
| 715 | current_dyntag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag, |
| 716 | 4, byte_order); |
| 717 | dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr, |
| 718 | 4, byte_order); |
| 719 | } |
| 720 | else |
| 721 | { |
| 722 | Elf64_External_Dyn *dynp = (Elf64_External_Dyn *) buf; |
| 723 | |
| 724 | current_dyntag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag, |
| 725 | 8, byte_order); |
| 726 | dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr, |
| 727 | 8, byte_order); |
| 728 | } |
| 729 | if (current_dyntag == DT_NULL) |
| 730 | break; |
| 731 | |
| 732 | if (current_dyntag == desired_dyntag) |
| 733 | { |
| 734 | if (ptr) |
| 735 | *ptr = dyn_ptr; |
| 736 | |
| 737 | if (ptr_addr) |
| 738 | *ptr_addr = base_addr + buf - ph_data->data (); |
| 739 | |
| 740 | return 1; |
| 741 | } |
| 742 | } |
| 743 | |
| 744 | return 0; |
| 745 | } |
| 746 | |
| 747 | /* Locate the base address of dynamic linker structs for SVR4 elf |
| 748 | targets. |
| 749 | |
| 750 | For SVR4 elf targets the address of the dynamic linker's runtime |
| 751 | structure is contained within the dynamic info section in the |
| 752 | executable file. The dynamic section is also mapped into the |
| 753 | inferior address space. Because the runtime loader fills in the |
| 754 | real address before starting the inferior, we have to read in the |
| 755 | dynamic info section from the inferior address space. |
| 756 | If there are any errors while trying to find the address, we |
| 757 | silently return 0, otherwise the found address is returned. */ |
| 758 | |
| 759 | static CORE_ADDR |
| 760 | elf_locate_base (void) |
| 761 | { |
| 762 | struct bound_minimal_symbol msymbol; |
| 763 | CORE_ADDR dyn_ptr, dyn_ptr_addr; |
| 764 | |
| 765 | /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this |
| 766 | instead of DT_DEBUG, although they sometimes contain an unused |
| 767 | DT_DEBUG. */ |
| 768 | if (scan_dyntag (DT_MIPS_RLD_MAP, current_program_space->exec_bfd (), |
| 769 | &dyn_ptr, NULL) |
| 770 | || scan_dyntag_auxv (DT_MIPS_RLD_MAP, &dyn_ptr, NULL)) |
| 771 | { |
| 772 | struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| 773 | gdb_byte *pbuf; |
| 774 | int pbuf_size = TYPE_LENGTH (ptr_type); |
| 775 | |
| 776 | pbuf = (gdb_byte *) alloca (pbuf_size); |
| 777 | /* DT_MIPS_RLD_MAP contains a pointer to the address |
| 778 | of the dynamic link structure. */ |
| 779 | if (target_read_memory (dyn_ptr, pbuf, pbuf_size)) |
| 780 | return 0; |
| 781 | return extract_typed_address (pbuf, ptr_type); |
| 782 | } |
| 783 | |
| 784 | /* Then check DT_MIPS_RLD_MAP_REL. MIPS executables now use this form |
| 785 | because of needing to support PIE. DT_MIPS_RLD_MAP will also exist |
| 786 | in non-PIE. */ |
| 787 | if (scan_dyntag (DT_MIPS_RLD_MAP_REL, current_program_space->exec_bfd (), |
| 788 | &dyn_ptr, &dyn_ptr_addr) |
| 789 | || scan_dyntag_auxv (DT_MIPS_RLD_MAP_REL, &dyn_ptr, &dyn_ptr_addr)) |
| 790 | { |
| 791 | struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| 792 | gdb_byte *pbuf; |
| 793 | int pbuf_size = TYPE_LENGTH (ptr_type); |
| 794 | |
| 795 | pbuf = (gdb_byte *) alloca (pbuf_size); |
| 796 | /* DT_MIPS_RLD_MAP_REL contains an offset from the address of the |
| 797 | DT slot to the address of the dynamic link structure. */ |
| 798 | if (target_read_memory (dyn_ptr + dyn_ptr_addr, pbuf, pbuf_size)) |
| 799 | return 0; |
| 800 | return extract_typed_address (pbuf, ptr_type); |
| 801 | } |
| 802 | |
| 803 | /* Find DT_DEBUG. */ |
| 804 | if (scan_dyntag (DT_DEBUG, current_program_space->exec_bfd (), &dyn_ptr, NULL) |
| 805 | || scan_dyntag_auxv (DT_DEBUG, &dyn_ptr, NULL)) |
| 806 | return dyn_ptr; |
| 807 | |
| 808 | /* This may be a static executable. Look for the symbol |
| 809 | conventionally named _r_debug, as a last resort. */ |
| 810 | msymbol = lookup_minimal_symbol ("_r_debug", NULL, |
| 811 | current_program_space->symfile_object_file); |
| 812 | if (msymbol.minsym != NULL) |
| 813 | return BMSYMBOL_VALUE_ADDRESS (msymbol); |
| 814 | |
| 815 | /* DT_DEBUG entry not found. */ |
| 816 | return 0; |
| 817 | } |
| 818 | |
| 819 | /* Locate the base address of dynamic linker structs. |
| 820 | |
| 821 | For both the SunOS and SVR4 shared library implementations, if the |
| 822 | inferior executable has been linked dynamically, there is a single |
| 823 | address somewhere in the inferior's data space which is the key to |
| 824 | locating all of the dynamic linker's runtime structures. This |
| 825 | address is the value of the debug base symbol. The job of this |
| 826 | function is to find and return that address, or to return 0 if there |
| 827 | is no such address (the executable is statically linked for example). |
| 828 | |
| 829 | For SunOS, the job is almost trivial, since the dynamic linker and |
| 830 | all of it's structures are statically linked to the executable at |
| 831 | link time. Thus the symbol for the address we are looking for has |
| 832 | already been added to the minimal symbol table for the executable's |
| 833 | objfile at the time the symbol file's symbols were read, and all we |
| 834 | have to do is look it up there. Note that we explicitly do NOT want |
| 835 | to find the copies in the shared library. |
| 836 | |
| 837 | The SVR4 version is a bit more complicated because the address |
| 838 | is contained somewhere in the dynamic info section. We have to go |
| 839 | to a lot more work to discover the address of the debug base symbol. |
| 840 | Because of this complexity, we cache the value we find and return that |
| 841 | value on subsequent invocations. Note there is no copy in the |
| 842 | executable symbol tables. */ |
| 843 | |
| 844 | static CORE_ADDR |
| 845 | locate_base (struct svr4_info *info) |
| 846 | { |
| 847 | /* Check to see if we have a currently valid address, and if so, avoid |
| 848 | doing all this work again and just return the cached address. If |
| 849 | we have no cached address, try to locate it in the dynamic info |
| 850 | section for ELF executables. There's no point in doing any of this |
| 851 | though if we don't have some link map offsets to work with. */ |
| 852 | |
| 853 | if (info->debug_base == 0 && svr4_have_link_map_offsets ()) |
| 854 | info->debug_base = elf_locate_base (); |
| 855 | return info->debug_base; |
| 856 | } |
| 857 | |
| 858 | /* Find the first element in the inferior's dynamic link map, and |
| 859 | return its address in the inferior. Return zero if the address |
| 860 | could not be determined. |
| 861 | |
| 862 | FIXME: Perhaps we should validate the info somehow, perhaps by |
| 863 | checking r_version for a known version number, or r_state for |
| 864 | RT_CONSISTENT. */ |
| 865 | |
| 866 | static CORE_ADDR |
| 867 | solib_svr4_r_map (struct svr4_info *info) |
| 868 | { |
| 869 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 870 | struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| 871 | CORE_ADDR addr = 0; |
| 872 | |
| 873 | try |
| 874 | { |
| 875 | addr = read_memory_typed_address (info->debug_base + lmo->r_map_offset, |
| 876 | ptr_type); |
| 877 | } |
| 878 | catch (const gdb_exception_error &ex) |
| 879 | { |
| 880 | exception_print (gdb_stderr, ex); |
| 881 | } |
| 882 | |
| 883 | return addr; |
| 884 | } |
| 885 | |
| 886 | /* Find r_brk from the inferior's debug base. */ |
| 887 | |
| 888 | static CORE_ADDR |
| 889 | solib_svr4_r_brk (struct svr4_info *info) |
| 890 | { |
| 891 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 892 | struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| 893 | |
| 894 | return read_memory_typed_address (info->debug_base + lmo->r_brk_offset, |
| 895 | ptr_type); |
| 896 | } |
| 897 | |
| 898 | /* Find the link map for the dynamic linker (if it is not in the |
| 899 | normal list of loaded shared objects). */ |
| 900 | |
| 901 | static CORE_ADDR |
| 902 | solib_svr4_r_ldsomap (struct svr4_info *info) |
| 903 | { |
| 904 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 905 | struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| 906 | enum bfd_endian byte_order = type_byte_order (ptr_type); |
| 907 | ULONGEST version = 0; |
| 908 | |
| 909 | try |
| 910 | { |
| 911 | /* Check version, and return zero if `struct r_debug' doesn't have |
| 912 | the r_ldsomap member. */ |
| 913 | version |
| 914 | = read_memory_unsigned_integer (info->debug_base + lmo->r_version_offset, |
| 915 | lmo->r_version_size, byte_order); |
| 916 | } |
| 917 | catch (const gdb_exception_error &ex) |
| 918 | { |
| 919 | exception_print (gdb_stderr, ex); |
| 920 | } |
| 921 | |
| 922 | if (version < 2 || lmo->r_ldsomap_offset == -1) |
| 923 | return 0; |
| 924 | |
| 925 | return read_memory_typed_address (info->debug_base + lmo->r_ldsomap_offset, |
| 926 | ptr_type); |
| 927 | } |
| 928 | |
| 929 | /* On Solaris systems with some versions of the dynamic linker, |
| 930 | ld.so's l_name pointer points to the SONAME in the string table |
| 931 | rather than into writable memory. So that GDB can find shared |
| 932 | libraries when loading a core file generated by gcore, ensure that |
| 933 | memory areas containing the l_name string are saved in the core |
| 934 | file. */ |
| 935 | |
| 936 | static int |
| 937 | svr4_keep_data_in_core (CORE_ADDR vaddr, unsigned long size) |
| 938 | { |
| 939 | struct svr4_info *info; |
| 940 | CORE_ADDR ldsomap; |
| 941 | CORE_ADDR name_lm; |
| 942 | |
| 943 | info = get_svr4_info (current_program_space); |
| 944 | |
| 945 | info->debug_base = 0; |
| 946 | locate_base (info); |
| 947 | if (!info->debug_base) |
| 948 | return 0; |
| 949 | |
| 950 | ldsomap = solib_svr4_r_ldsomap (info); |
| 951 | if (!ldsomap) |
| 952 | return 0; |
| 953 | |
| 954 | std::unique_ptr<lm_info_svr4> li = lm_info_read (ldsomap); |
| 955 | name_lm = li != NULL ? li->l_name : 0; |
| 956 | |
| 957 | return (name_lm >= vaddr && name_lm < vaddr + size); |
| 958 | } |
| 959 | |
| 960 | /* See solist.h. */ |
| 961 | |
| 962 | static int |
| 963 | open_symbol_file_object (int from_tty) |
| 964 | { |
| 965 | CORE_ADDR lm, l_name; |
| 966 | struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| 967 | struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| 968 | int l_name_size = TYPE_LENGTH (ptr_type); |
| 969 | gdb::byte_vector l_name_buf (l_name_size); |
| 970 | struct svr4_info *info = get_svr4_info (current_program_space); |
| 971 | symfile_add_flags add_flags = 0; |
| 972 | |
| 973 | if (from_tty) |
| 974 | add_flags |= SYMFILE_VERBOSE; |
| 975 | |
| 976 | if (current_program_space->symfile_object_file) |
| 977 | if (!query (_("Attempt to reload symbols from process? "))) |
| 978 | return 0; |
| 979 | |
| 980 | /* Always locate the debug struct, in case it has moved. */ |
| 981 | info->debug_base = 0; |
| 982 | if (locate_base (info) == 0) |
| 983 | return 0; /* failed somehow... */ |
| 984 | |
| 985 | /* First link map member should be the executable. */ |
| 986 | lm = solib_svr4_r_map (info); |
| 987 | if (lm == 0) |
| 988 | return 0; /* failed somehow... */ |
| 989 | |
| 990 | /* Read address of name from target memory to GDB. */ |
| 991 | read_memory (lm + lmo->l_name_offset, l_name_buf.data (), l_name_size); |
| 992 | |
| 993 | /* Convert the address to host format. */ |
| 994 | l_name = extract_typed_address (l_name_buf.data (), ptr_type); |
| 995 | |
| 996 | if (l_name == 0) |
| 997 | return 0; /* No filename. */ |
| 998 | |
| 999 | /* Now fetch the filename from target memory. */ |
| 1000 | gdb::unique_xmalloc_ptr<char> filename |
| 1001 | = target_read_string (l_name, SO_NAME_MAX_PATH_SIZE - 1); |
| 1002 | |
| 1003 | if (filename == nullptr) |
| 1004 | { |
| 1005 | warning (_("failed to read exec filename from attached file")); |
| 1006 | return 0; |
| 1007 | } |
| 1008 | |
| 1009 | /* Have a pathname: read the symbol file. */ |
| 1010 | symbol_file_add_main (filename.get (), add_flags); |
| 1011 | |
| 1012 | return 1; |
| 1013 | } |
| 1014 | |
| 1015 | /* Data exchange structure for the XML parser as returned by |
| 1016 | svr4_current_sos_via_xfer_libraries. */ |
| 1017 | |
| 1018 | struct svr4_library_list |
| 1019 | { |
| 1020 | struct so_list *head, **tailp; |
| 1021 | |
| 1022 | /* Inferior address of struct link_map used for the main executable. It is |
| 1023 | NULL if not known. */ |
| 1024 | CORE_ADDR main_lm; |
| 1025 | }; |
| 1026 | |
| 1027 | /* This module's 'free_objfile' observer. */ |
| 1028 | |
| 1029 | static void |
| 1030 | svr4_free_objfile_observer (struct objfile *objfile) |
| 1031 | { |
| 1032 | probes_table_remove_objfile_probes (objfile); |
| 1033 | } |
| 1034 | |
| 1035 | /* Implementation for target_so_ops.free_so. */ |
| 1036 | |
| 1037 | static void |
| 1038 | svr4_free_so (struct so_list *so) |
| 1039 | { |
| 1040 | lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info; |
| 1041 | |
| 1042 | delete li; |
| 1043 | } |
| 1044 | |
| 1045 | /* Implement target_so_ops.clear_so. */ |
| 1046 | |
| 1047 | static void |
| 1048 | svr4_clear_so (struct so_list *so) |
| 1049 | { |
| 1050 | lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info; |
| 1051 | |
| 1052 | if (li != NULL) |
| 1053 | li->l_addr_p = 0; |
| 1054 | } |
| 1055 | |
| 1056 | /* Free so_list built so far (called via cleanup). */ |
| 1057 | |
| 1058 | static void |
| 1059 | svr4_free_library_list (void *p_list) |
| 1060 | { |
| 1061 | struct so_list *list = *(struct so_list **) p_list; |
| 1062 | |
| 1063 | while (list != NULL) |
| 1064 | { |
| 1065 | struct so_list *next = list->next; |
| 1066 | |
| 1067 | free_so (list); |
| 1068 | list = next; |
| 1069 | } |
| 1070 | } |
| 1071 | |
| 1072 | /* Copy library list. */ |
| 1073 | |
| 1074 | static struct so_list * |
| 1075 | svr4_copy_library_list (struct so_list *src) |
| 1076 | { |
| 1077 | struct so_list *dst = NULL; |
| 1078 | struct so_list **link = &dst; |
| 1079 | |
| 1080 | while (src != NULL) |
| 1081 | { |
| 1082 | struct so_list *newobj; |
| 1083 | |
| 1084 | newobj = XNEW (struct so_list); |
| 1085 | memcpy (newobj, src, sizeof (struct so_list)); |
| 1086 | |
| 1087 | lm_info_svr4 *src_li = (lm_info_svr4 *) src->lm_info; |
| 1088 | newobj->lm_info = new lm_info_svr4 (*src_li); |
| 1089 | |
| 1090 | newobj->next = NULL; |
| 1091 | *link = newobj; |
| 1092 | link = &newobj->next; |
| 1093 | |
| 1094 | src = src->next; |
| 1095 | } |
| 1096 | |
| 1097 | return dst; |
| 1098 | } |
| 1099 | |
| 1100 | #ifdef HAVE_LIBEXPAT |
| 1101 | |
| 1102 | #include "xml-support.h" |
| 1103 | |
| 1104 | /* Handle the start of a <library> element. Note: new elements are added |
| 1105 | at the tail of the list, keeping the list in order. */ |
| 1106 | |
| 1107 | static void |
| 1108 | library_list_start_library (struct gdb_xml_parser *parser, |
| 1109 | const struct gdb_xml_element *element, |
| 1110 | void *user_data, |
| 1111 | std::vector<gdb_xml_value> &attributes) |
| 1112 | { |
| 1113 | struct svr4_library_list *list = (struct svr4_library_list *) user_data; |
| 1114 | const char *name |
| 1115 | = (const char *) xml_find_attribute (attributes, "name")->value.get (); |
| 1116 | ULONGEST *lmp |
| 1117 | = (ULONGEST *) xml_find_attribute (attributes, "lm")->value.get (); |
| 1118 | ULONGEST *l_addrp |
| 1119 | = (ULONGEST *) xml_find_attribute (attributes, "l_addr")->value.get (); |
| 1120 | ULONGEST *l_ldp |
| 1121 | = (ULONGEST *) xml_find_attribute (attributes, "l_ld")->value.get (); |
| 1122 | struct so_list *new_elem; |
| 1123 | |
| 1124 | new_elem = XCNEW (struct so_list); |
| 1125 | lm_info_svr4 *li = new lm_info_svr4; |
| 1126 | new_elem->lm_info = li; |
| 1127 | li->lm_addr = *lmp; |
| 1128 | li->l_addr_inferior = *l_addrp; |
| 1129 | li->l_ld = *l_ldp; |
| 1130 | |
| 1131 | strncpy (new_elem->so_name, name, sizeof (new_elem->so_name) - 1); |
| 1132 | new_elem->so_name[sizeof (new_elem->so_name) - 1] = 0; |
| 1133 | strcpy (new_elem->so_original_name, new_elem->so_name); |
| 1134 | |
| 1135 | *list->tailp = new_elem; |
| 1136 | list->tailp = &new_elem->next; |
| 1137 | } |
| 1138 | |
| 1139 | /* Handle the start of a <library-list-svr4> element. */ |
| 1140 | |
| 1141 | static void |
| 1142 | svr4_library_list_start_list (struct gdb_xml_parser *parser, |
| 1143 | const struct gdb_xml_element *element, |
| 1144 | void *user_data, |
| 1145 | std::vector<gdb_xml_value> &attributes) |
| 1146 | { |
| 1147 | struct svr4_library_list *list = (struct svr4_library_list *) user_data; |
| 1148 | const char *version |
| 1149 | = (const char *) xml_find_attribute (attributes, "version")->value.get (); |
| 1150 | struct gdb_xml_value *main_lm = xml_find_attribute (attributes, "main-lm"); |
| 1151 | |
| 1152 | if (strcmp (version, "1.0") != 0) |
| 1153 | gdb_xml_error (parser, |
| 1154 | _("SVR4 Library list has unsupported version \"%s\""), |
| 1155 | version); |
| 1156 | |
| 1157 | if (main_lm) |
| 1158 | list->main_lm = *(ULONGEST *) main_lm->value.get (); |
| 1159 | } |
| 1160 | |
| 1161 | /* The allowed elements and attributes for an XML library list. |
| 1162 | The root element is a <library-list>. */ |
| 1163 | |
| 1164 | static const struct gdb_xml_attribute svr4_library_attributes[] = |
| 1165 | { |
| 1166 | { "name", GDB_XML_AF_NONE, NULL, NULL }, |
| 1167 | { "lm", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, |
| 1168 | { "l_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, |
| 1169 | { "l_ld", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, |
| 1170 | { NULL, GDB_XML_AF_NONE, NULL, NULL } |
| 1171 | }; |
| 1172 | |
| 1173 | static const struct gdb_xml_element svr4_library_list_children[] = |
| 1174 | { |
| 1175 | { |
| 1176 | "library", svr4_library_attributes, NULL, |
| 1177 | GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL, |
| 1178 | library_list_start_library, NULL |
| 1179 | }, |
| 1180 | { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL } |
| 1181 | }; |
| 1182 | |
| 1183 | static const struct gdb_xml_attribute svr4_library_list_attributes[] = |
| 1184 | { |
| 1185 | { "version", GDB_XML_AF_NONE, NULL, NULL }, |
| 1186 | { "main-lm", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL }, |
| 1187 | { NULL, GDB_XML_AF_NONE, NULL, NULL } |
| 1188 | }; |
| 1189 | |
| 1190 | static const struct gdb_xml_element svr4_library_list_elements[] = |
| 1191 | { |
| 1192 | { "library-list-svr4", svr4_library_list_attributes, svr4_library_list_children, |
| 1193 | GDB_XML_EF_NONE, svr4_library_list_start_list, NULL }, |
| 1194 | { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL } |
| 1195 | }; |
| 1196 | |
| 1197 | /* Parse qXfer:libraries:read packet into *SO_LIST_RETURN. Return 1 if |
| 1198 | |
| 1199 | Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such |
| 1200 | case. Return 1 if *SO_LIST_RETURN contains the library list, it may be |
| 1201 | empty, caller is responsible for freeing all its entries. */ |
| 1202 | |
| 1203 | static int |
| 1204 | svr4_parse_libraries (const char *document, struct svr4_library_list *list) |
| 1205 | { |
| 1206 | auto cleanup = make_scope_exit ([&] () |
| 1207 | { |
| 1208 | svr4_free_library_list (&list->head); |
| 1209 | }); |
| 1210 | |
| 1211 | memset (list, 0, sizeof (*list)); |
| 1212 | list->tailp = &list->head; |
| 1213 | if (gdb_xml_parse_quick (_("target library list"), "library-list-svr4.dtd", |
| 1214 | svr4_library_list_elements, document, list) == 0) |
| 1215 | { |
| 1216 | /* Parsed successfully, keep the result. */ |
| 1217 | cleanup.release (); |
| 1218 | return 1; |
| 1219 | } |
| 1220 | |
| 1221 | return 0; |
| 1222 | } |
| 1223 | |
| 1224 | /* Attempt to get so_list from target via qXfer:libraries-svr4:read packet. |
| 1225 | |
| 1226 | Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such |
| 1227 | case. Return 1 if *SO_LIST_RETURN contains the library list, it may be |
| 1228 | empty, caller is responsible for freeing all its entries. |
| 1229 | |
| 1230 | Note that ANNEX must be NULL if the remote does not explicitly allow |
| 1231 | qXfer:libraries-svr4:read packets with non-empty annexes. Support for |
| 1232 | this can be checked using target_augmented_libraries_svr4_read (). */ |
| 1233 | |
| 1234 | static int |
| 1235 | svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list, |
| 1236 | const char *annex) |
| 1237 | { |
| 1238 | gdb_assert (annex == NULL || target_augmented_libraries_svr4_read ()); |
| 1239 | |
| 1240 | /* Fetch the list of shared libraries. */ |
| 1241 | gdb::optional<gdb::char_vector> svr4_library_document |
| 1242 | = target_read_stralloc (current_top_target (), TARGET_OBJECT_LIBRARIES_SVR4, |
| 1243 | annex); |
| 1244 | if (!svr4_library_document) |
| 1245 | return 0; |
| 1246 | |
| 1247 | return svr4_parse_libraries (svr4_library_document->data (), list); |
| 1248 | } |
| 1249 | |
| 1250 | #else |
| 1251 | |
| 1252 | static int |
| 1253 | svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list, |
| 1254 | const char *annex) |
| 1255 | { |
| 1256 | return 0; |
| 1257 | } |
| 1258 | |
| 1259 | #endif |
| 1260 | |
| 1261 | /* If no shared library information is available from the dynamic |
| 1262 | linker, build a fallback list from other sources. */ |
| 1263 | |
| 1264 | static struct so_list * |
| 1265 | svr4_default_sos (svr4_info *info) |
| 1266 | { |
| 1267 | struct so_list *newobj; |
| 1268 | |
| 1269 | if (!info->debug_loader_offset_p) |
| 1270 | return NULL; |
| 1271 | |
| 1272 | newobj = XCNEW (struct so_list); |
| 1273 | lm_info_svr4 *li = new lm_info_svr4; |
| 1274 | newobj->lm_info = li; |
| 1275 | |
| 1276 | /* Nothing will ever check the other fields if we set l_addr_p. */ |
| 1277 | li->l_addr = info->debug_loader_offset; |
| 1278 | li->l_addr_p = 1; |
| 1279 | |
| 1280 | strncpy (newobj->so_name, info->debug_loader_name, SO_NAME_MAX_PATH_SIZE - 1); |
| 1281 | newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; |
| 1282 | strcpy (newobj->so_original_name, newobj->so_name); |
| 1283 | |
| 1284 | return newobj; |
| 1285 | } |
| 1286 | |
| 1287 | /* Read the whole inferior libraries chain starting at address LM. |
| 1288 | Expect the first entry in the chain's previous entry to be PREV_LM. |
| 1289 | Add the entries to the tail referenced by LINK_PTR_PTR. Ignore the |
| 1290 | first entry if IGNORE_FIRST and set global MAIN_LM_ADDR according |
| 1291 | to it. Returns nonzero upon success. If zero is returned the |
| 1292 | entries stored to LINK_PTR_PTR are still valid although they may |
| 1293 | represent only part of the inferior library list. */ |
| 1294 | |
| 1295 | static int |
| 1296 | svr4_read_so_list (svr4_info *info, CORE_ADDR lm, CORE_ADDR prev_lm, |
| 1297 | struct so_list ***link_ptr_ptr, int ignore_first) |
| 1298 | { |
| 1299 | CORE_ADDR first_l_name = 0; |
| 1300 | CORE_ADDR next_lm; |
| 1301 | |
| 1302 | for (; lm != 0; prev_lm = lm, lm = next_lm) |
| 1303 | { |
| 1304 | so_list_up newobj (XCNEW (struct so_list)); |
| 1305 | |
| 1306 | lm_info_svr4 *li = lm_info_read (lm).release (); |
| 1307 | newobj->lm_info = li; |
| 1308 | if (li == NULL) |
| 1309 | return 0; |
| 1310 | |
| 1311 | next_lm = li->l_next; |
| 1312 | |
| 1313 | if (li->l_prev != prev_lm) |
| 1314 | { |
| 1315 | warning (_("Corrupted shared library list: %s != %s"), |
| 1316 | paddress (target_gdbarch (), prev_lm), |
| 1317 | paddress (target_gdbarch (), li->l_prev)); |
| 1318 | return 0; |
| 1319 | } |
| 1320 | |
| 1321 | /* For SVR4 versions, the first entry in the link map is for the |
| 1322 | inferior executable, so we must ignore it. For some versions of |
| 1323 | SVR4, it has no name. For others (Solaris 2.3 for example), it |
| 1324 | does have a name, so we can no longer use a missing name to |
| 1325 | decide when to ignore it. */ |
| 1326 | if (ignore_first && li->l_prev == 0) |
| 1327 | { |
| 1328 | first_l_name = li->l_name; |
| 1329 | info->main_lm_addr = li->lm_addr; |
| 1330 | continue; |
| 1331 | } |
| 1332 | |
| 1333 | /* Extract this shared object's name. */ |
| 1334 | gdb::unique_xmalloc_ptr<char> buffer |
| 1335 | = target_read_string (li->l_name, SO_NAME_MAX_PATH_SIZE - 1); |
| 1336 | if (buffer == nullptr) |
| 1337 | { |
| 1338 | /* If this entry's l_name address matches that of the |
| 1339 | inferior executable, then this is not a normal shared |
| 1340 | object, but (most likely) a vDSO. In this case, silently |
| 1341 | skip it; otherwise emit a warning. */ |
| 1342 | if (first_l_name == 0 || li->l_name != first_l_name) |
| 1343 | warning (_("Can't read pathname for load map.")); |
| 1344 | continue; |
| 1345 | } |
| 1346 | |
| 1347 | strncpy (newobj->so_name, buffer.get (), SO_NAME_MAX_PATH_SIZE - 1); |
| 1348 | newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; |
| 1349 | strcpy (newobj->so_original_name, newobj->so_name); |
| 1350 | |
| 1351 | /* If this entry has no name, or its name matches the name |
| 1352 | for the main executable, don't include it in the list. */ |
| 1353 | if (! newobj->so_name[0] || match_main (newobj->so_name)) |
| 1354 | continue; |
| 1355 | |
| 1356 | newobj->next = 0; |
| 1357 | /* Don't free it now. */ |
| 1358 | **link_ptr_ptr = newobj.release (); |
| 1359 | *link_ptr_ptr = &(**link_ptr_ptr)->next; |
| 1360 | } |
| 1361 | |
| 1362 | return 1; |
| 1363 | } |
| 1364 | |
| 1365 | /* Read the full list of currently loaded shared objects directly |
| 1366 | from the inferior, without referring to any libraries read and |
| 1367 | stored by the probes interface. Handle special cases relating |
| 1368 | to the first elements of the list. */ |
| 1369 | |
| 1370 | static struct so_list * |
| 1371 | svr4_current_sos_direct (struct svr4_info *info) |
| 1372 | { |
| 1373 | CORE_ADDR lm; |
| 1374 | struct so_list *head = NULL; |
| 1375 | struct so_list **link_ptr = &head; |
| 1376 | int ignore_first; |
| 1377 | struct svr4_library_list library_list; |
| 1378 | |
| 1379 | /* Fall back to manual examination of the target if the packet is not |
| 1380 | supported or gdbserver failed to find DT_DEBUG. gdb.server/solib-list.exp |
| 1381 | tests a case where gdbserver cannot find the shared libraries list while |
| 1382 | GDB itself is able to find it via SYMFILE_OBJFILE. |
| 1383 | |
| 1384 | Unfortunately statically linked inferiors will also fall back through this |
| 1385 | suboptimal code path. */ |
| 1386 | |
| 1387 | info->using_xfer = svr4_current_sos_via_xfer_libraries (&library_list, |
| 1388 | NULL); |
| 1389 | if (info->using_xfer) |
| 1390 | { |
| 1391 | if (library_list.main_lm) |
| 1392 | info->main_lm_addr = library_list.main_lm; |
| 1393 | |
| 1394 | return library_list.head ? library_list.head : svr4_default_sos (info); |
| 1395 | } |
| 1396 | |
| 1397 | /* Always locate the debug struct, in case it has moved. */ |
| 1398 | info->debug_base = 0; |
| 1399 | locate_base (info); |
| 1400 | |
| 1401 | /* If we can't find the dynamic linker's base structure, this |
| 1402 | must not be a dynamically linked executable. Hmm. */ |
| 1403 | if (! info->debug_base) |
| 1404 | return svr4_default_sos (info); |
| 1405 | |
| 1406 | /* Assume that everything is a library if the dynamic loader was loaded |
| 1407 | late by a static executable. */ |
| 1408 | if (current_program_space->exec_bfd () |
| 1409 | && bfd_get_section_by_name (current_program_space->exec_bfd (), |
| 1410 | ".dynamic") == NULL) |
| 1411 | ignore_first = 0; |
| 1412 | else |
| 1413 | ignore_first = 1; |
| 1414 | |
| 1415 | auto cleanup = make_scope_exit ([&] () |
| 1416 | { |
| 1417 | svr4_free_library_list (&head); |
| 1418 | }); |
| 1419 | |
| 1420 | /* Walk the inferior's link map list, and build our list of |
| 1421 | `struct so_list' nodes. */ |
| 1422 | lm = solib_svr4_r_map (info); |
| 1423 | if (lm) |
| 1424 | svr4_read_so_list (info, lm, 0, &link_ptr, ignore_first); |
| 1425 | |
| 1426 | /* On Solaris, the dynamic linker is not in the normal list of |
| 1427 | shared objects, so make sure we pick it up too. Having |
| 1428 | symbol information for the dynamic linker is quite crucial |
| 1429 | for skipping dynamic linker resolver code. */ |
| 1430 | lm = solib_svr4_r_ldsomap (info); |
| 1431 | if (lm) |
| 1432 | svr4_read_so_list (info, lm, 0, &link_ptr, 0); |
| 1433 | |
| 1434 | cleanup.release (); |
| 1435 | |
| 1436 | if (head == NULL) |
| 1437 | return svr4_default_sos (info); |
| 1438 | |
| 1439 | return head; |
| 1440 | } |
| 1441 | |
| 1442 | /* Implement the main part of the "current_sos" target_so_ops |
| 1443 | method. */ |
| 1444 | |
| 1445 | static struct so_list * |
| 1446 | svr4_current_sos_1 (svr4_info *info) |
| 1447 | { |
| 1448 | /* If the solib list has been read and stored by the probes |
| 1449 | interface then we return a copy of the stored list. */ |
| 1450 | if (info->solib_list != NULL) |
| 1451 | return svr4_copy_library_list (info->solib_list); |
| 1452 | |
| 1453 | /* Otherwise obtain the solib list directly from the inferior. */ |
| 1454 | return svr4_current_sos_direct (info); |
| 1455 | } |
| 1456 | |
| 1457 | /* Implement the "current_sos" target_so_ops method. */ |
| 1458 | |
| 1459 | static struct so_list * |
| 1460 | svr4_current_sos (void) |
| 1461 | { |
| 1462 | svr4_info *info = get_svr4_info (current_program_space); |
| 1463 | struct so_list *so_head = svr4_current_sos_1 (info); |
| 1464 | struct mem_range vsyscall_range; |
| 1465 | |
| 1466 | /* Filter out the vDSO module, if present. Its symbol file would |
| 1467 | not be found on disk. The vDSO/vsyscall's OBJFILE is instead |
| 1468 | managed by symfile-mem.c:add_vsyscall_page. */ |
| 1469 | if (gdbarch_vsyscall_range (target_gdbarch (), &vsyscall_range) |
| 1470 | && vsyscall_range.length != 0) |
| 1471 | { |
| 1472 | struct so_list **sop; |
| 1473 | |
| 1474 | sop = &so_head; |
| 1475 | while (*sop != NULL) |
| 1476 | { |
| 1477 | struct so_list *so = *sop; |
| 1478 | |
| 1479 | /* We can't simply match the vDSO by starting address alone, |
| 1480 | because lm_info->l_addr_inferior (and also l_addr) do not |
| 1481 | necessarily represent the real starting address of the |
| 1482 | ELF if the vDSO's ELF itself is "prelinked". The l_ld |
| 1483 | field (the ".dynamic" section of the shared object) |
| 1484 | always points at the absolute/resolved address though. |
| 1485 | So check whether that address is inside the vDSO's |
| 1486 | mapping instead. |
| 1487 | |
| 1488 | E.g., on Linux 3.16 (x86_64) the vDSO is a regular |
| 1489 | 0-based ELF, and we see: |
| 1490 | |
| 1491 | (gdb) info auxv |
| 1492 | 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffb000 |
| 1493 | (gdb) p/x *_r_debug.r_map.l_next |
| 1494 | $1 = {l_addr = 0x7ffff7ffb000, ..., l_ld = 0x7ffff7ffb318, ...} |
| 1495 | |
| 1496 | And on Linux 2.6.32 (x86_64) we see: |
| 1497 | |
| 1498 | (gdb) info auxv |
| 1499 | 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffe000 |
| 1500 | (gdb) p/x *_r_debug.r_map.l_next |
| 1501 | $5 = {l_addr = 0x7ffff88fe000, ..., l_ld = 0x7ffff7ffe580, ... } |
| 1502 | |
| 1503 | Dumping that vDSO shows: |
| 1504 | |
| 1505 | (gdb) info proc mappings |
| 1506 | 0x7ffff7ffe000 0x7ffff7fff000 0x1000 0 [vdso] |
| 1507 | (gdb) dump memory vdso.bin 0x7ffff7ffe000 0x7ffff7fff000 |
| 1508 | # readelf -Wa vdso.bin |
| 1509 | [...] |
| 1510 | Entry point address: 0xffffffffff700700 |
| 1511 | [...] |
| 1512 | Section Headers: |
| 1513 | [Nr] Name Type Address Off Size |
| 1514 | [ 0] NULL 0000000000000000 000000 000000 |
| 1515 | [ 1] .hash HASH ffffffffff700120 000120 000038 |
| 1516 | [ 2] .dynsym DYNSYM ffffffffff700158 000158 0000d8 |
| 1517 | [...] |
| 1518 | [ 9] .dynamic DYNAMIC ffffffffff700580 000580 0000f0 |
| 1519 | */ |
| 1520 | |
| 1521 | lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info; |
| 1522 | |
| 1523 | if (address_in_mem_range (li->l_ld, &vsyscall_range)) |
| 1524 | { |
| 1525 | *sop = so->next; |
| 1526 | free_so (so); |
| 1527 | break; |
| 1528 | } |
| 1529 | |
| 1530 | sop = &so->next; |
| 1531 | } |
| 1532 | } |
| 1533 | |
| 1534 | return so_head; |
| 1535 | } |
| 1536 | |
| 1537 | /* Get the address of the link_map for a given OBJFILE. */ |
| 1538 | |
| 1539 | CORE_ADDR |
| 1540 | svr4_fetch_objfile_link_map (struct objfile *objfile) |
| 1541 | { |
| 1542 | struct svr4_info *info = get_svr4_info (objfile->pspace); |
| 1543 | |
| 1544 | /* Cause svr4_current_sos() to be run if it hasn't been already. */ |
| 1545 | if (info->main_lm_addr == 0) |
| 1546 | solib_add (NULL, 0, auto_solib_add); |
| 1547 | |
| 1548 | /* svr4_current_sos() will set main_lm_addr for the main executable. */ |
| 1549 | if (objfile == current_program_space->symfile_object_file) |
| 1550 | return info->main_lm_addr; |
| 1551 | |
| 1552 | /* If OBJFILE is a separate debug object file, look for the |
| 1553 | original object file. */ |
| 1554 | if (objfile->separate_debug_objfile_backlink != NULL) |
| 1555 | objfile = objfile->separate_debug_objfile_backlink; |
| 1556 | |
| 1557 | /* The other link map addresses may be found by examining the list |
| 1558 | of shared libraries. */ |
| 1559 | for (struct so_list *so : current_program_space->solibs ()) |
| 1560 | if (so->objfile == objfile) |
| 1561 | { |
| 1562 | lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info; |
| 1563 | |
| 1564 | return li->lm_addr; |
| 1565 | } |
| 1566 | |
| 1567 | /* Not found! */ |
| 1568 | return 0; |
| 1569 | } |
| 1570 | |
| 1571 | /* On some systems, the only way to recognize the link map entry for |
| 1572 | the main executable file is by looking at its name. Return |
| 1573 | non-zero iff SONAME matches one of the known main executable names. */ |
| 1574 | |
| 1575 | static int |
| 1576 | match_main (const char *soname) |
| 1577 | { |
| 1578 | const char * const *mainp; |
| 1579 | |
| 1580 | for (mainp = main_name_list; *mainp != NULL; mainp++) |
| 1581 | { |
| 1582 | if (strcmp (soname, *mainp) == 0) |
| 1583 | return (1); |
| 1584 | } |
| 1585 | |
| 1586 | return (0); |
| 1587 | } |
| 1588 | |
| 1589 | /* Return 1 if PC lies in the dynamic symbol resolution code of the |
| 1590 | SVR4 run time loader. */ |
| 1591 | |
| 1592 | int |
| 1593 | svr4_in_dynsym_resolve_code (CORE_ADDR pc) |
| 1594 | { |
| 1595 | struct svr4_info *info = get_svr4_info (current_program_space); |
| 1596 | |
| 1597 | return ((pc >= info->interp_text_sect_low |
| 1598 | && pc < info->interp_text_sect_high) |
| 1599 | || (pc >= info->interp_plt_sect_low |
| 1600 | && pc < info->interp_plt_sect_high) |
| 1601 | || in_plt_section (pc) |
| 1602 | || in_gnu_ifunc_stub (pc)); |
| 1603 | } |
| 1604 | |
| 1605 | /* Given an executable's ABFD and target, compute the entry-point |
| 1606 | address. */ |
| 1607 | |
| 1608 | static CORE_ADDR |
| 1609 | exec_entry_point (struct bfd *abfd, struct target_ops *targ) |
| 1610 | { |
| 1611 | CORE_ADDR addr; |
| 1612 | |
| 1613 | /* KevinB wrote ... for most targets, the address returned by |
| 1614 | bfd_get_start_address() is the entry point for the start |
| 1615 | function. But, for some targets, bfd_get_start_address() returns |
| 1616 | the address of a function descriptor from which the entry point |
| 1617 | address may be extracted. This address is extracted by |
| 1618 | gdbarch_convert_from_func_ptr_addr(). The method |
| 1619 | gdbarch_convert_from_func_ptr_addr() is the merely the identify |
| 1620 | function for targets which don't use function descriptors. */ |
| 1621 | addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| 1622 | bfd_get_start_address (abfd), |
| 1623 | targ); |
| 1624 | return gdbarch_addr_bits_remove (target_gdbarch (), addr); |
| 1625 | } |
| 1626 | |
| 1627 | /* A probe and its associated action. */ |
| 1628 | |
| 1629 | struct probe_and_action |
| 1630 | { |
| 1631 | /* The probe. */ |
| 1632 | probe *prob; |
| 1633 | |
| 1634 | /* The relocated address of the probe. */ |
| 1635 | CORE_ADDR address; |
| 1636 | |
| 1637 | /* The action. */ |
| 1638 | enum probe_action action; |
| 1639 | |
| 1640 | /* The objfile where this probe was found. */ |
| 1641 | struct objfile *objfile; |
| 1642 | }; |
| 1643 | |
| 1644 | /* Returns a hash code for the probe_and_action referenced by p. */ |
| 1645 | |
| 1646 | static hashval_t |
| 1647 | hash_probe_and_action (const void *p) |
| 1648 | { |
| 1649 | const struct probe_and_action *pa = (const struct probe_and_action *) p; |
| 1650 | |
| 1651 | return (hashval_t) pa->address; |
| 1652 | } |
| 1653 | |
| 1654 | /* Returns non-zero if the probe_and_actions referenced by p1 and p2 |
| 1655 | are equal. */ |
| 1656 | |
| 1657 | static int |
| 1658 | equal_probe_and_action (const void *p1, const void *p2) |
| 1659 | { |
| 1660 | const struct probe_and_action *pa1 = (const struct probe_and_action *) p1; |
| 1661 | const struct probe_and_action *pa2 = (const struct probe_and_action *) p2; |
| 1662 | |
| 1663 | return pa1->address == pa2->address; |
| 1664 | } |
| 1665 | |
| 1666 | /* Traversal function for probes_table_remove_objfile_probes. */ |
| 1667 | |
| 1668 | static int |
| 1669 | probes_table_htab_remove_objfile_probes (void **slot, void *info) |
| 1670 | { |
| 1671 | probe_and_action *pa = (probe_and_action *) *slot; |
| 1672 | struct objfile *objfile = (struct objfile *) info; |
| 1673 | |
| 1674 | if (pa->objfile == objfile) |
| 1675 | htab_clear_slot (get_svr4_info (objfile->pspace)->probes_table.get (), |
| 1676 | slot); |
| 1677 | |
| 1678 | return 1; |
| 1679 | } |
| 1680 | |
| 1681 | /* Remove all probes that belong to OBJFILE from the probes table. */ |
| 1682 | |
| 1683 | static void |
| 1684 | probes_table_remove_objfile_probes (struct objfile *objfile) |
| 1685 | { |
| 1686 | svr4_info *info = get_svr4_info (objfile->pspace); |
| 1687 | if (info->probes_table != nullptr) |
| 1688 | htab_traverse_noresize (info->probes_table.get (), |
| 1689 | probes_table_htab_remove_objfile_probes, objfile); |
| 1690 | } |
| 1691 | |
| 1692 | /* Register a solib event probe and its associated action in the |
| 1693 | probes table. */ |
| 1694 | |
| 1695 | static void |
| 1696 | register_solib_event_probe (svr4_info *info, struct objfile *objfile, |
| 1697 | probe *prob, CORE_ADDR address, |
| 1698 | enum probe_action action) |
| 1699 | { |
| 1700 | struct probe_and_action lookup, *pa; |
| 1701 | void **slot; |
| 1702 | |
| 1703 | /* Create the probes table, if necessary. */ |
| 1704 | if (info->probes_table == NULL) |
| 1705 | info->probes_table.reset (htab_create_alloc (1, hash_probe_and_action, |
| 1706 | equal_probe_and_action, |
| 1707 | xfree, xcalloc, xfree)); |
| 1708 | |
| 1709 | lookup.address = address; |
| 1710 | slot = htab_find_slot (info->probes_table.get (), &lookup, INSERT); |
| 1711 | gdb_assert (*slot == HTAB_EMPTY_ENTRY); |
| 1712 | |
| 1713 | pa = XCNEW (struct probe_and_action); |
| 1714 | pa->prob = prob; |
| 1715 | pa->address = address; |
| 1716 | pa->action = action; |
| 1717 | pa->objfile = objfile; |
| 1718 | |
| 1719 | *slot = pa; |
| 1720 | } |
| 1721 | |
| 1722 | /* Get the solib event probe at the specified location, and the |
| 1723 | action associated with it. Returns NULL if no solib event probe |
| 1724 | was found. */ |
| 1725 | |
| 1726 | static struct probe_and_action * |
| 1727 | solib_event_probe_at (struct svr4_info *info, CORE_ADDR address) |
| 1728 | { |
| 1729 | struct probe_and_action lookup; |
| 1730 | void **slot; |
| 1731 | |
| 1732 | lookup.address = address; |
| 1733 | slot = htab_find_slot (info->probes_table.get (), &lookup, NO_INSERT); |
| 1734 | |
| 1735 | if (slot == NULL) |
| 1736 | return NULL; |
| 1737 | |
| 1738 | return (struct probe_and_action *) *slot; |
| 1739 | } |
| 1740 | |
| 1741 | /* Decide what action to take when the specified solib event probe is |
| 1742 | hit. */ |
| 1743 | |
| 1744 | static enum probe_action |
| 1745 | solib_event_probe_action (struct probe_and_action *pa) |
| 1746 | { |
| 1747 | enum probe_action action; |
| 1748 | unsigned probe_argc = 0; |
| 1749 | struct frame_info *frame = get_current_frame (); |
| 1750 | |
| 1751 | action = pa->action; |
| 1752 | if (action == DO_NOTHING || action == PROBES_INTERFACE_FAILED) |
| 1753 | return action; |
| 1754 | |
| 1755 | gdb_assert (action == FULL_RELOAD || action == UPDATE_OR_RELOAD); |
| 1756 | |
| 1757 | /* Check that an appropriate number of arguments has been supplied. |
| 1758 | We expect: |
| 1759 | arg0: Lmid_t lmid (mandatory) |
| 1760 | arg1: struct r_debug *debug_base (mandatory) |
| 1761 | arg2: struct link_map *new (optional, for incremental updates) */ |
| 1762 | try |
| 1763 | { |
| 1764 | probe_argc = pa->prob->get_argument_count (get_frame_arch (frame)); |
| 1765 | } |
| 1766 | catch (const gdb_exception_error &ex) |
| 1767 | { |
| 1768 | exception_print (gdb_stderr, ex); |
| 1769 | probe_argc = 0; |
| 1770 | } |
| 1771 | |
| 1772 | /* If get_argument_count throws an exception, probe_argc will be set |
| 1773 | to zero. However, if pa->prob does not have arguments, then |
| 1774 | get_argument_count will succeed but probe_argc will also be zero. |
| 1775 | Both cases happen because of different things, but they are |
| 1776 | treated equally here: action will be set to |
| 1777 | PROBES_INTERFACE_FAILED. */ |
| 1778 | if (probe_argc == 2) |
| 1779 | action = FULL_RELOAD; |
| 1780 | else if (probe_argc < 2) |
| 1781 | action = PROBES_INTERFACE_FAILED; |
| 1782 | |
| 1783 | return action; |
| 1784 | } |
| 1785 | |
| 1786 | /* Populate the shared object list by reading the entire list of |
| 1787 | shared objects from the inferior. Handle special cases relating |
| 1788 | to the first elements of the list. Returns nonzero on success. */ |
| 1789 | |
| 1790 | static int |
| 1791 | solist_update_full (struct svr4_info *info) |
| 1792 | { |
| 1793 | free_solib_list (info); |
| 1794 | info->solib_list = svr4_current_sos_direct (info); |
| 1795 | |
| 1796 | return 1; |
| 1797 | } |
| 1798 | |
| 1799 | /* Update the shared object list starting from the link-map entry |
| 1800 | passed by the linker in the probe's third argument. Returns |
| 1801 | nonzero if the list was successfully updated, or zero to indicate |
| 1802 | failure. */ |
| 1803 | |
| 1804 | static int |
| 1805 | solist_update_incremental (struct svr4_info *info, CORE_ADDR lm) |
| 1806 | { |
| 1807 | struct so_list *tail; |
| 1808 | CORE_ADDR prev_lm; |
| 1809 | |
| 1810 | /* svr4_current_sos_direct contains logic to handle a number of |
| 1811 | special cases relating to the first elements of the list. To |
| 1812 | avoid duplicating this logic we defer to solist_update_full |
| 1813 | if the list is empty. */ |
| 1814 | if (info->solib_list == NULL) |
| 1815 | return 0; |
| 1816 | |
| 1817 | /* Fall back to a full update if we are using a remote target |
| 1818 | that does not support incremental transfers. */ |
| 1819 | if (info->using_xfer && !target_augmented_libraries_svr4_read ()) |
| 1820 | return 0; |
| 1821 | |
| 1822 | /* Walk to the end of the list. */ |
| 1823 | for (tail = info->solib_list; tail->next != NULL; tail = tail->next) |
| 1824 | /* Nothing. */; |
| 1825 | |
| 1826 | lm_info_svr4 *li = (lm_info_svr4 *) tail->lm_info; |
| 1827 | prev_lm = li->lm_addr; |
| 1828 | |
| 1829 | /* Read the new objects. */ |
| 1830 | if (info->using_xfer) |
| 1831 | { |
| 1832 | struct svr4_library_list library_list; |
| 1833 | char annex[64]; |
| 1834 | |
| 1835 | xsnprintf (annex, sizeof (annex), "start=%s;prev=%s", |
| 1836 | phex_nz (lm, sizeof (lm)), |
| 1837 | phex_nz (prev_lm, sizeof (prev_lm))); |
| 1838 | if (!svr4_current_sos_via_xfer_libraries (&library_list, annex)) |
| 1839 | return 0; |
| 1840 | |
| 1841 | tail->next = library_list.head; |
| 1842 | } |
| 1843 | else |
| 1844 | { |
| 1845 | struct so_list **link = &tail->next; |
| 1846 | |
| 1847 | /* IGNORE_FIRST may safely be set to zero here because the |
| 1848 | above check and deferral to solist_update_full ensures |
| 1849 | that this call to svr4_read_so_list will never see the |
| 1850 | first element. */ |
| 1851 | if (!svr4_read_so_list (info, lm, prev_lm, &link, 0)) |
| 1852 | return 0; |
| 1853 | } |
| 1854 | |
| 1855 | return 1; |
| 1856 | } |
| 1857 | |
| 1858 | /* Disable the probes-based linker interface and revert to the |
| 1859 | original interface. We don't reset the breakpoints as the |
| 1860 | ones set up for the probes-based interface are adequate. */ |
| 1861 | |
| 1862 | static void |
| 1863 | disable_probes_interface (svr4_info *info) |
| 1864 | { |
| 1865 | warning (_("Probes-based dynamic linker interface failed.\n" |
| 1866 | "Reverting to original interface.")); |
| 1867 | |
| 1868 | free_probes_table (info); |
| 1869 | free_solib_list (info); |
| 1870 | } |
| 1871 | |
| 1872 | /* Update the solib list as appropriate when using the |
| 1873 | probes-based linker interface. Do nothing if using the |
| 1874 | standard interface. */ |
| 1875 | |
| 1876 | static void |
| 1877 | svr4_handle_solib_event (void) |
| 1878 | { |
| 1879 | struct svr4_info *info = get_svr4_info (current_program_space); |
| 1880 | struct probe_and_action *pa; |
| 1881 | enum probe_action action; |
| 1882 | struct value *val = NULL; |
| 1883 | CORE_ADDR pc, debug_base, lm = 0; |
| 1884 | struct frame_info *frame = get_current_frame (); |
| 1885 | |
| 1886 | /* Do nothing if not using the probes interface. */ |
| 1887 | if (info->probes_table == NULL) |
| 1888 | return; |
| 1889 | |
| 1890 | /* If anything goes wrong we revert to the original linker |
| 1891 | interface. */ |
| 1892 | auto cleanup = make_scope_exit ([info] () |
| 1893 | { |
| 1894 | disable_probes_interface (info); |
| 1895 | }); |
| 1896 | |
| 1897 | pc = regcache_read_pc (get_current_regcache ()); |
| 1898 | pa = solib_event_probe_at (info, pc); |
| 1899 | if (pa == NULL) |
| 1900 | return; |
| 1901 | |
| 1902 | action = solib_event_probe_action (pa); |
| 1903 | if (action == PROBES_INTERFACE_FAILED) |
| 1904 | return; |
| 1905 | |
| 1906 | if (action == DO_NOTHING) |
| 1907 | { |
| 1908 | cleanup.release (); |
| 1909 | return; |
| 1910 | } |
| 1911 | |
| 1912 | /* evaluate_argument looks up symbols in the dynamic linker |
| 1913 | using find_pc_section. find_pc_section is accelerated by a cache |
| 1914 | called the section map. The section map is invalidated every |
| 1915 | time a shared library is loaded or unloaded, and if the inferior |
| 1916 | is generating a lot of shared library events then the section map |
| 1917 | will be updated every time svr4_handle_solib_event is called. |
| 1918 | We called find_pc_section in svr4_create_solib_event_breakpoints, |
| 1919 | so we can guarantee that the dynamic linker's sections are in the |
| 1920 | section map. We can therefore inhibit section map updates across |
| 1921 | these calls to evaluate_argument and save a lot of time. */ |
| 1922 | { |
| 1923 | scoped_restore inhibit_updates |
| 1924 | = inhibit_section_map_updates (current_program_space); |
| 1925 | |
| 1926 | try |
| 1927 | { |
| 1928 | val = pa->prob->evaluate_argument (1, frame); |
| 1929 | } |
| 1930 | catch (const gdb_exception_error &ex) |
| 1931 | { |
| 1932 | exception_print (gdb_stderr, ex); |
| 1933 | val = NULL; |
| 1934 | } |
| 1935 | |
| 1936 | if (val == NULL) |
| 1937 | return; |
| 1938 | |
| 1939 | debug_base = value_as_address (val); |
| 1940 | if (debug_base == 0) |
| 1941 | return; |
| 1942 | |
| 1943 | /* Always locate the debug struct, in case it moved. */ |
| 1944 | info->debug_base = 0; |
| 1945 | if (locate_base (info) == 0) |
| 1946 | { |
| 1947 | /* It's possible for the reloc_complete probe to be triggered before |
| 1948 | the linker has set the DT_DEBUG pointer (for example, when the |
| 1949 | linker has finished relocating an LD_AUDIT library or its |
| 1950 | dependencies). Since we can't yet handle libraries from other link |
| 1951 | namespaces, we don't lose anything by ignoring them here. */ |
| 1952 | struct value *link_map_id_val; |
| 1953 | try |
| 1954 | { |
| 1955 | link_map_id_val = pa->prob->evaluate_argument (0, frame); |
| 1956 | } |
| 1957 | catch (const gdb_exception_error) |
| 1958 | { |
| 1959 | link_map_id_val = NULL; |
| 1960 | } |
| 1961 | /* glibc and illumos' libc both define LM_ID_BASE as zero. */ |
| 1962 | if (link_map_id_val != NULL && value_as_long (link_map_id_val) != 0) |
| 1963 | action = DO_NOTHING; |
| 1964 | else |
| 1965 | return; |
| 1966 | } |
| 1967 | |
| 1968 | /* GDB does not currently support libraries loaded via dlmopen |
| 1969 | into namespaces other than the initial one. We must ignore |
| 1970 | any namespace other than the initial namespace here until |
| 1971 | support for this is added to GDB. */ |
| 1972 | if (debug_base != info->debug_base) |
| 1973 | action = DO_NOTHING; |
| 1974 | |
| 1975 | if (action == UPDATE_OR_RELOAD) |
| 1976 | { |
| 1977 | try |
| 1978 | { |
| 1979 | val = pa->prob->evaluate_argument (2, frame); |
| 1980 | } |
| 1981 | catch (const gdb_exception_error &ex) |
| 1982 | { |
| 1983 | exception_print (gdb_stderr, ex); |
| 1984 | return; |
| 1985 | } |
| 1986 | |
| 1987 | if (val != NULL) |
| 1988 | lm = value_as_address (val); |
| 1989 | |
| 1990 | if (lm == 0) |
| 1991 | action = FULL_RELOAD; |
| 1992 | } |
| 1993 | |
| 1994 | /* Resume section map updates. Closing the scope is |
| 1995 | sufficient. */ |
| 1996 | } |
| 1997 | |
| 1998 | if (action == UPDATE_OR_RELOAD) |
| 1999 | { |
| 2000 | if (!solist_update_incremental (info, lm)) |
| 2001 | action = FULL_RELOAD; |
| 2002 | } |
| 2003 | |
| 2004 | if (action == FULL_RELOAD) |
| 2005 | { |
| 2006 | if (!solist_update_full (info)) |
| 2007 | return; |
| 2008 | } |
| 2009 | |
| 2010 | cleanup.release (); |
| 2011 | } |
| 2012 | |
| 2013 | /* Helper function for svr4_update_solib_event_breakpoints. */ |
| 2014 | |
| 2015 | static bool |
| 2016 | svr4_update_solib_event_breakpoint (struct breakpoint *b) |
| 2017 | { |
| 2018 | struct bp_location *loc; |
| 2019 | |
| 2020 | if (b->type != bp_shlib_event) |
| 2021 | { |
| 2022 | /* Continue iterating. */ |
| 2023 | return false; |
| 2024 | } |
| 2025 | |
| 2026 | for (loc = b->loc; loc != NULL; loc = loc->next) |
| 2027 | { |
| 2028 | struct svr4_info *info; |
| 2029 | struct probe_and_action *pa; |
| 2030 | |
| 2031 | info = solib_svr4_pspace_data.get (loc->pspace); |
| 2032 | if (info == NULL || info->probes_table == NULL) |
| 2033 | continue; |
| 2034 | |
| 2035 | pa = solib_event_probe_at (info, loc->address); |
| 2036 | if (pa == NULL) |
| 2037 | continue; |
| 2038 | |
| 2039 | if (pa->action == DO_NOTHING) |
| 2040 | { |
| 2041 | if (b->enable_state == bp_disabled && stop_on_solib_events) |
| 2042 | enable_breakpoint (b); |
| 2043 | else if (b->enable_state == bp_enabled && !stop_on_solib_events) |
| 2044 | disable_breakpoint (b); |
| 2045 | } |
| 2046 | |
| 2047 | break; |
| 2048 | } |
| 2049 | |
| 2050 | /* Continue iterating. */ |
| 2051 | return false; |
| 2052 | } |
| 2053 | |
| 2054 | /* Enable or disable optional solib event breakpoints as appropriate. |
| 2055 | Called whenever stop_on_solib_events is changed. */ |
| 2056 | |
| 2057 | static void |
| 2058 | svr4_update_solib_event_breakpoints (void) |
| 2059 | { |
| 2060 | iterate_over_breakpoints (svr4_update_solib_event_breakpoint); |
| 2061 | } |
| 2062 | |
| 2063 | /* Create and register solib event breakpoints. PROBES is an array |
| 2064 | of NUM_PROBES elements, each of which is vector of probes. A |
| 2065 | solib event breakpoint will be created and registered for each |
| 2066 | probe. */ |
| 2067 | |
| 2068 | static void |
| 2069 | svr4_create_probe_breakpoints (svr4_info *info, struct gdbarch *gdbarch, |
| 2070 | const std::vector<probe *> *probes, |
| 2071 | struct objfile *objfile) |
| 2072 | { |
| 2073 | for (int i = 0; i < NUM_PROBES; i++) |
| 2074 | { |
| 2075 | enum probe_action action = probe_info[i].action; |
| 2076 | |
| 2077 | for (probe *p : probes[i]) |
| 2078 | { |
| 2079 | CORE_ADDR address = p->get_relocated_address (objfile); |
| 2080 | |
| 2081 | create_solib_event_breakpoint (gdbarch, address); |
| 2082 | register_solib_event_probe (info, objfile, p, address, action); |
| 2083 | } |
| 2084 | } |
| 2085 | |
| 2086 | svr4_update_solib_event_breakpoints (); |
| 2087 | } |
| 2088 | |
| 2089 | /* Find all the glibc named probes. Only if all of the probes are found, then |
| 2090 | create them and return true. Otherwise return false. If WITH_PREFIX is set |
| 2091 | then add "rtld" to the front of the probe names. */ |
| 2092 | static bool |
| 2093 | svr4_find_and_create_probe_breakpoints (svr4_info *info, |
| 2094 | struct gdbarch *gdbarch, |
| 2095 | struct obj_section *os, |
| 2096 | bool with_prefix) |
| 2097 | { |
| 2098 | std::vector<probe *> probes[NUM_PROBES]; |
| 2099 | |
| 2100 | for (int i = 0; i < NUM_PROBES; i++) |
| 2101 | { |
| 2102 | const char *name = probe_info[i].name; |
| 2103 | char buf[32]; |
| 2104 | |
| 2105 | /* Fedora 17 and Red Hat Enterprise Linux 6.2-6.4 shipped with an early |
| 2106 | version of the probes code in which the probes' names were prefixed |
| 2107 | with "rtld_" and the "map_failed" probe did not exist. The locations |
| 2108 | of the probes are otherwise the same, so we check for probes with |
| 2109 | prefixed names if probes with unprefixed names are not present. */ |
| 2110 | if (with_prefix) |
| 2111 | { |
| 2112 | xsnprintf (buf, sizeof (buf), "rtld_%s", name); |
| 2113 | name = buf; |
| 2114 | } |
| 2115 | |
| 2116 | probes[i] = find_probes_in_objfile (os->objfile, "rtld", name); |
| 2117 | |
| 2118 | /* The "map_failed" probe did not exist in early |
| 2119 | versions of the probes code in which the probes' |
| 2120 | names were prefixed with "rtld_". */ |
| 2121 | if (with_prefix && streq (name, "rtld_map_failed")) |
| 2122 | continue; |
| 2123 | |
| 2124 | /* Ensure at least one probe for the current name was found. */ |
| 2125 | if (probes[i].empty ()) |
| 2126 | return false; |
| 2127 | |
| 2128 | /* Ensure probe arguments can be evaluated. */ |
| 2129 | for (probe *p : probes[i]) |
| 2130 | { |
| 2131 | if (!p->can_evaluate_arguments ()) |
| 2132 | return false; |
| 2133 | /* This will fail if the probe is invalid. This has been seen on Arm |
| 2134 | due to references to symbols that have been resolved away. */ |
| 2135 | try |
| 2136 | { |
| 2137 | p->get_argument_count (gdbarch); |
| 2138 | } |
| 2139 | catch (const gdb_exception_error &ex) |
| 2140 | { |
| 2141 | exception_print (gdb_stderr, ex); |
| 2142 | warning (_("Initializing probes-based dynamic linker interface " |
| 2143 | "failed.\nReverting to original interface.")); |
| 2144 | return false; |
| 2145 | } |
| 2146 | } |
| 2147 | } |
| 2148 | |
| 2149 | /* All probes found. Now create them. */ |
| 2150 | svr4_create_probe_breakpoints (info, gdbarch, probes, os->objfile); |
| 2151 | return true; |
| 2152 | } |
| 2153 | |
| 2154 | /* Both the SunOS and the SVR4 dynamic linkers call a marker function |
| 2155 | before and after mapping and unmapping shared libraries. The sole |
| 2156 | purpose of this method is to allow debuggers to set a breakpoint so |
| 2157 | they can track these changes. |
| 2158 | |
| 2159 | Some versions of the glibc dynamic linker contain named probes |
| 2160 | to allow more fine grained stopping. Given the address of the |
| 2161 | original marker function, this function attempts to find these |
| 2162 | probes, and if found, sets breakpoints on those instead. If the |
| 2163 | probes aren't found, a single breakpoint is set on the original |
| 2164 | marker function. */ |
| 2165 | |
| 2166 | static void |
| 2167 | svr4_create_solib_event_breakpoints (svr4_info *info, struct gdbarch *gdbarch, |
| 2168 | CORE_ADDR address) |
| 2169 | { |
| 2170 | struct obj_section *os = find_pc_section (address); |
| 2171 | |
| 2172 | if (os == nullptr |
| 2173 | || (!svr4_find_and_create_probe_breakpoints (info, gdbarch, os, false) |
| 2174 | && !svr4_find_and_create_probe_breakpoints (info, gdbarch, os, true))) |
| 2175 | create_solib_event_breakpoint (gdbarch, address); |
| 2176 | } |
| 2177 | |
| 2178 | /* Helper function for gdb_bfd_lookup_symbol. */ |
| 2179 | |
| 2180 | static int |
| 2181 | cmp_name_and_sec_flags (const asymbol *sym, const void *data) |
| 2182 | { |
| 2183 | return (strcmp (sym->name, (const char *) data) == 0 |
| 2184 | && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0); |
| 2185 | } |
| 2186 | /* Arrange for dynamic linker to hit breakpoint. |
| 2187 | |
| 2188 | Both the SunOS and the SVR4 dynamic linkers have, as part of their |
| 2189 | debugger interface, support for arranging for the inferior to hit |
| 2190 | a breakpoint after mapping in the shared libraries. This function |
| 2191 | enables that breakpoint. |
| 2192 | |
| 2193 | For SunOS, there is a special flag location (in_debugger) which we |
| 2194 | set to 1. When the dynamic linker sees this flag set, it will set |
| 2195 | a breakpoint at a location known only to itself, after saving the |
| 2196 | original contents of that place and the breakpoint address itself, |
| 2197 | in it's own internal structures. When we resume the inferior, it |
| 2198 | will eventually take a SIGTRAP when it runs into the breakpoint. |
| 2199 | We handle this (in a different place) by restoring the contents of |
| 2200 | the breakpointed location (which is only known after it stops), |
| 2201 | chasing around to locate the shared libraries that have been |
| 2202 | loaded, then resuming. |
| 2203 | |
| 2204 | For SVR4, the debugger interface structure contains a member (r_brk) |
| 2205 | which is statically initialized at the time the shared library is |
| 2206 | built, to the offset of a function (_r_debug_state) which is guaran- |
| 2207 | teed to be called once before mapping in a library, and again when |
| 2208 | the mapping is complete. At the time we are examining this member, |
| 2209 | it contains only the unrelocated offset of the function, so we have |
| 2210 | to do our own relocation. Later, when the dynamic linker actually |
| 2211 | runs, it relocates r_brk to be the actual address of _r_debug_state(). |
| 2212 | |
| 2213 | The debugger interface structure also contains an enumeration which |
| 2214 | is set to either RT_ADD or RT_DELETE prior to changing the mapping, |
| 2215 | depending upon whether or not the library is being mapped or unmapped, |
| 2216 | and then set to RT_CONSISTENT after the library is mapped/unmapped. */ |
| 2217 | |
| 2218 | static int |
| 2219 | enable_break (struct svr4_info *info, int from_tty) |
| 2220 | { |
| 2221 | struct bound_minimal_symbol msymbol; |
| 2222 | const char * const *bkpt_namep; |
| 2223 | asection *interp_sect; |
| 2224 | CORE_ADDR sym_addr; |
| 2225 | |
| 2226 | info->interp_text_sect_low = info->interp_text_sect_high = 0; |
| 2227 | info->interp_plt_sect_low = info->interp_plt_sect_high = 0; |
| 2228 | |
| 2229 | /* If we already have a shared library list in the target, and |
| 2230 | r_debug contains r_brk, set the breakpoint there - this should |
| 2231 | mean r_brk has already been relocated. Assume the dynamic linker |
| 2232 | is the object containing r_brk. */ |
| 2233 | |
| 2234 | solib_add (NULL, from_tty, auto_solib_add); |
| 2235 | sym_addr = 0; |
| 2236 | if (info->debug_base && solib_svr4_r_map (info) != 0) |
| 2237 | sym_addr = solib_svr4_r_brk (info); |
| 2238 | |
| 2239 | if (sym_addr != 0) |
| 2240 | { |
| 2241 | struct obj_section *os; |
| 2242 | |
| 2243 | sym_addr = gdbarch_addr_bits_remove |
| 2244 | (target_gdbarch (), |
| 2245 | gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| 2246 | sym_addr, |
| 2247 | current_top_target ())); |
| 2248 | |
| 2249 | /* On at least some versions of Solaris there's a dynamic relocation |
| 2250 | on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if |
| 2251 | we get control before the dynamic linker has self-relocated. |
| 2252 | Check if SYM_ADDR is in a known section, if it is assume we can |
| 2253 | trust its value. This is just a heuristic though, it could go away |
| 2254 | or be replaced if it's getting in the way. |
| 2255 | |
| 2256 | On ARM we need to know whether the ISA of rtld_db_dlactivity (or |
| 2257 | however it's spelled in your particular system) is ARM or Thumb. |
| 2258 | That knowledge is encoded in the address, if it's Thumb the low bit |
| 2259 | is 1. However, we've stripped that info above and it's not clear |
| 2260 | what all the consequences are of passing a non-addr_bits_remove'd |
| 2261 | address to svr4_create_solib_event_breakpoints. The call to |
| 2262 | find_pc_section verifies we know about the address and have some |
| 2263 | hope of computing the right kind of breakpoint to use (via |
| 2264 | symbol info). It does mean that GDB needs to be pointed at a |
| 2265 | non-stripped version of the dynamic linker in order to obtain |
| 2266 | information it already knows about. Sigh. */ |
| 2267 | |
| 2268 | os = find_pc_section (sym_addr); |
| 2269 | if (os != NULL) |
| 2270 | { |
| 2271 | /* Record the relocated start and end address of the dynamic linker |
| 2272 | text and plt section for svr4_in_dynsym_resolve_code. */ |
| 2273 | bfd *tmp_bfd; |
| 2274 | CORE_ADDR load_addr; |
| 2275 | |
| 2276 | tmp_bfd = os->objfile->obfd; |
| 2277 | load_addr = os->objfile->text_section_offset (); |
| 2278 | |
| 2279 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
| 2280 | if (interp_sect) |
| 2281 | { |
| 2282 | info->interp_text_sect_low |
| 2283 | = bfd_section_vma (interp_sect) + load_addr; |
| 2284 | info->interp_text_sect_high |
| 2285 | = info->interp_text_sect_low + bfd_section_size (interp_sect); |
| 2286 | } |
| 2287 | interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); |
| 2288 | if (interp_sect) |
| 2289 | { |
| 2290 | info->interp_plt_sect_low |
| 2291 | = bfd_section_vma (interp_sect) + load_addr; |
| 2292 | info->interp_plt_sect_high |
| 2293 | = info->interp_plt_sect_low + bfd_section_size (interp_sect); |
| 2294 | } |
| 2295 | |
| 2296 | svr4_create_solib_event_breakpoints (info, target_gdbarch (), sym_addr); |
| 2297 | return 1; |
| 2298 | } |
| 2299 | } |
| 2300 | |
| 2301 | /* Find the program interpreter; if not found, warn the user and drop |
| 2302 | into the old breakpoint at symbol code. */ |
| 2303 | gdb::optional<gdb::byte_vector> interp_name_holder |
| 2304 | = find_program_interpreter (); |
| 2305 | if (interp_name_holder) |
| 2306 | { |
| 2307 | const char *interp_name = (const char *) interp_name_holder->data (); |
| 2308 | CORE_ADDR load_addr = 0; |
| 2309 | int load_addr_found = 0; |
| 2310 | int loader_found_in_list = 0; |
| 2311 | struct target_ops *tmp_bfd_target; |
| 2312 | |
| 2313 | sym_addr = 0; |
| 2314 | |
| 2315 | /* Now we need to figure out where the dynamic linker was |
| 2316 | loaded so that we can load its symbols and place a breakpoint |
| 2317 | in the dynamic linker itself. |
| 2318 | |
| 2319 | This address is stored on the stack. However, I've been unable |
| 2320 | to find any magic formula to find it for Solaris (appears to |
| 2321 | be trivial on GNU/Linux). Therefore, we have to try an alternate |
| 2322 | mechanism to find the dynamic linker's base address. */ |
| 2323 | |
| 2324 | gdb_bfd_ref_ptr tmp_bfd; |
| 2325 | try |
| 2326 | { |
| 2327 | tmp_bfd = solib_bfd_open (interp_name); |
| 2328 | } |
| 2329 | catch (const gdb_exception &ex) |
| 2330 | { |
| 2331 | } |
| 2332 | |
| 2333 | if (tmp_bfd == NULL) |
| 2334 | goto bkpt_at_symbol; |
| 2335 | |
| 2336 | /* Now convert the TMP_BFD into a target. That way target, as |
| 2337 | well as BFD operations can be used. */ |
| 2338 | tmp_bfd_target = target_bfd_reopen (tmp_bfd); |
| 2339 | |
| 2340 | /* On a running target, we can get the dynamic linker's base |
| 2341 | address from the shared library table. */ |
| 2342 | for (struct so_list *so : current_program_space->solibs ()) |
| 2343 | { |
| 2344 | if (svr4_same_1 (interp_name, so->so_original_name)) |
| 2345 | { |
| 2346 | load_addr_found = 1; |
| 2347 | loader_found_in_list = 1; |
| 2348 | load_addr = lm_addr_check (so, tmp_bfd.get ()); |
| 2349 | break; |
| 2350 | } |
| 2351 | } |
| 2352 | |
| 2353 | /* If we were not able to find the base address of the loader |
| 2354 | from our so_list, then try using the AT_BASE auxilliary entry. */ |
| 2355 | if (!load_addr_found) |
| 2356 | if (target_auxv_search (current_top_target (), AT_BASE, &load_addr) > 0) |
| 2357 | { |
| 2358 | int addr_bit = gdbarch_addr_bit (target_gdbarch ()); |
| 2359 | |
| 2360 | /* Ensure LOAD_ADDR has proper sign in its possible upper bits so |
| 2361 | that `+ load_addr' will overflow CORE_ADDR width not creating |
| 2362 | invalid addresses like 0x101234567 for 32bit inferiors on 64bit |
| 2363 | GDB. */ |
| 2364 | |
| 2365 | if (addr_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT)) |
| 2366 | { |
| 2367 | CORE_ADDR space_size = (CORE_ADDR) 1 << addr_bit; |
| 2368 | CORE_ADDR tmp_entry_point = exec_entry_point (tmp_bfd.get (), |
| 2369 | tmp_bfd_target); |
| 2370 | |
| 2371 | gdb_assert (load_addr < space_size); |
| 2372 | |
| 2373 | /* TMP_ENTRY_POINT exceeding SPACE_SIZE would be for prelinked |
| 2374 | 64bit ld.so with 32bit executable, it should not happen. */ |
| 2375 | |
| 2376 | if (tmp_entry_point < space_size |
| 2377 | && tmp_entry_point + load_addr >= space_size) |
| 2378 | load_addr -= space_size; |
| 2379 | } |
| 2380 | |
| 2381 | load_addr_found = 1; |
| 2382 | } |
| 2383 | |
| 2384 | /* Otherwise we find the dynamic linker's base address by examining |
| 2385 | the current pc (which should point at the entry point for the |
| 2386 | dynamic linker) and subtracting the offset of the entry point. |
| 2387 | |
| 2388 | This is more fragile than the previous approaches, but is a good |
| 2389 | fallback method because it has actually been working well in |
| 2390 | most cases. */ |
| 2391 | if (!load_addr_found) |
| 2392 | { |
| 2393 | struct regcache *regcache |
| 2394 | = get_thread_arch_regcache (current_inferior ()->process_target (), |
| 2395 | inferior_ptid, target_gdbarch ()); |
| 2396 | |
| 2397 | load_addr = (regcache_read_pc (regcache) |
| 2398 | - exec_entry_point (tmp_bfd.get (), tmp_bfd_target)); |
| 2399 | } |
| 2400 | |
| 2401 | if (!loader_found_in_list) |
| 2402 | { |
| 2403 | info->debug_loader_name = xstrdup (interp_name); |
| 2404 | info->debug_loader_offset_p = 1; |
| 2405 | info->debug_loader_offset = load_addr; |
| 2406 | solib_add (NULL, from_tty, auto_solib_add); |
| 2407 | } |
| 2408 | |
| 2409 | /* Record the relocated start and end address of the dynamic linker |
| 2410 | text and plt section for svr4_in_dynsym_resolve_code. */ |
| 2411 | interp_sect = bfd_get_section_by_name (tmp_bfd.get (), ".text"); |
| 2412 | if (interp_sect) |
| 2413 | { |
| 2414 | info->interp_text_sect_low |
| 2415 | = bfd_section_vma (interp_sect) + load_addr; |
| 2416 | info->interp_text_sect_high |
| 2417 | = info->interp_text_sect_low + bfd_section_size (interp_sect); |
| 2418 | } |
| 2419 | interp_sect = bfd_get_section_by_name (tmp_bfd.get (), ".plt"); |
| 2420 | if (interp_sect) |
| 2421 | { |
| 2422 | info->interp_plt_sect_low |
| 2423 | = bfd_section_vma (interp_sect) + load_addr; |
| 2424 | info->interp_plt_sect_high |
| 2425 | = info->interp_plt_sect_low + bfd_section_size (interp_sect); |
| 2426 | } |
| 2427 | |
| 2428 | /* Now try to set a breakpoint in the dynamic linker. */ |
| 2429 | for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) |
| 2430 | { |
| 2431 | sym_addr = gdb_bfd_lookup_symbol (tmp_bfd.get (), |
| 2432 | cmp_name_and_sec_flags, |
| 2433 | *bkpt_namep); |
| 2434 | if (sym_addr != 0) |
| 2435 | break; |
| 2436 | } |
| 2437 | |
| 2438 | if (sym_addr != 0) |
| 2439 | /* Convert 'sym_addr' from a function pointer to an address. |
| 2440 | Because we pass tmp_bfd_target instead of the current |
| 2441 | target, this will always produce an unrelocated value. */ |
| 2442 | sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| 2443 | sym_addr, |
| 2444 | tmp_bfd_target); |
| 2445 | |
| 2446 | /* We're done with both the temporary bfd and target. Closing |
| 2447 | the target closes the underlying bfd, because it holds the |
| 2448 | only remaining reference. */ |
| 2449 | target_close (tmp_bfd_target); |
| 2450 | |
| 2451 | if (sym_addr != 0) |
| 2452 | { |
| 2453 | svr4_create_solib_event_breakpoints (info, target_gdbarch (), |
| 2454 | load_addr + sym_addr); |
| 2455 | return 1; |
| 2456 | } |
| 2457 | |
| 2458 | /* For whatever reason we couldn't set a breakpoint in the dynamic |
| 2459 | linker. Warn and drop into the old code. */ |
| 2460 | bkpt_at_symbol: |
| 2461 | warning (_("Unable to find dynamic linker breakpoint function.\n" |
| 2462 | "GDB will be unable to debug shared library initializers\n" |
| 2463 | "and track explicitly loaded dynamic code.")); |
| 2464 | } |
| 2465 | |
| 2466 | /* Scan through the lists of symbols, trying to look up the symbol and |
| 2467 | set a breakpoint there. Terminate loop when we/if we succeed. */ |
| 2468 | |
| 2469 | objfile *objf = current_program_space->symfile_object_file; |
| 2470 | for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) |
| 2471 | { |
| 2472 | msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, objf); |
| 2473 | if ((msymbol.minsym != NULL) |
| 2474 | && (BMSYMBOL_VALUE_ADDRESS (msymbol) != 0)) |
| 2475 | { |
| 2476 | sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol); |
| 2477 | sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| 2478 | sym_addr, |
| 2479 | current_top_target ()); |
| 2480 | svr4_create_solib_event_breakpoints (info, target_gdbarch (), |
| 2481 | sym_addr); |
| 2482 | return 1; |
| 2483 | } |
| 2484 | } |
| 2485 | |
| 2486 | if (interp_name_holder && !current_inferior ()->attach_flag) |
| 2487 | { |
| 2488 | for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++) |
| 2489 | { |
| 2490 | msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, objf); |
| 2491 | if ((msymbol.minsym != NULL) |
| 2492 | && (BMSYMBOL_VALUE_ADDRESS (msymbol) != 0)) |
| 2493 | { |
| 2494 | sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol); |
| 2495 | sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| 2496 | sym_addr, |
| 2497 | current_top_target ()); |
| 2498 | svr4_create_solib_event_breakpoints (info, target_gdbarch (), |
| 2499 | sym_addr); |
| 2500 | return 1; |
| 2501 | } |
| 2502 | } |
| 2503 | } |
| 2504 | return 0; |
| 2505 | } |
| 2506 | |
| 2507 | /* Read the ELF program headers from ABFD. */ |
| 2508 | |
| 2509 | static gdb::optional<gdb::byte_vector> |
| 2510 | read_program_headers_from_bfd (bfd *abfd) |
| 2511 | { |
| 2512 | Elf_Internal_Ehdr *ehdr = elf_elfheader (abfd); |
| 2513 | int phdrs_size = ehdr->e_phnum * ehdr->e_phentsize; |
| 2514 | if (phdrs_size == 0) |
| 2515 | return {}; |
| 2516 | |
| 2517 | gdb::byte_vector buf (phdrs_size); |
| 2518 | if (bfd_seek (abfd, ehdr->e_phoff, SEEK_SET) != 0 |
| 2519 | || bfd_bread (buf.data (), phdrs_size, abfd) != phdrs_size) |
| 2520 | return {}; |
| 2521 | |
| 2522 | return buf; |
| 2523 | } |
| 2524 | |
| 2525 | /* Return 1 and fill *DISPLACEMENTP with detected PIE offset of inferior |
| 2526 | exec_bfd. Otherwise return 0. |
| 2527 | |
| 2528 | We relocate all of the sections by the same amount. This |
| 2529 | behavior is mandated by recent editions of the System V ABI. |
| 2530 | According to the System V Application Binary Interface, |
| 2531 | Edition 4.1, page 5-5: |
| 2532 | |
| 2533 | ... Though the system chooses virtual addresses for |
| 2534 | individual processes, it maintains the segments' relative |
| 2535 | positions. Because position-independent code uses relative |
| 2536 | addressing between segments, the difference between |
| 2537 | virtual addresses in memory must match the difference |
| 2538 | between virtual addresses in the file. The difference |
| 2539 | between the virtual address of any segment in memory and |
| 2540 | the corresponding virtual address in the file is thus a |
| 2541 | single constant value for any one executable or shared |
| 2542 | object in a given process. This difference is the base |
| 2543 | address. One use of the base address is to relocate the |
| 2544 | memory image of the program during dynamic linking. |
| 2545 | |
| 2546 | The same language also appears in Edition 4.0 of the System V |
| 2547 | ABI and is left unspecified in some of the earlier editions. |
| 2548 | |
| 2549 | Decide if the objfile needs to be relocated. As indicated above, we will |
| 2550 | only be here when execution is stopped. But during attachment PC can be at |
| 2551 | arbitrary address therefore regcache_read_pc can be misleading (contrary to |
| 2552 | the auxv AT_ENTRY value). Moreover for executable with interpreter section |
| 2553 | regcache_read_pc would point to the interpreter and not the main executable. |
| 2554 | |
| 2555 | So, to summarize, relocations are necessary when the start address obtained |
| 2556 | from the executable is different from the address in auxv AT_ENTRY entry. |
| 2557 | |
| 2558 | [ The astute reader will note that we also test to make sure that |
| 2559 | the executable in question has the DYNAMIC flag set. It is my |
| 2560 | opinion that this test is unnecessary (undesirable even). It |
| 2561 | was added to avoid inadvertent relocation of an executable |
| 2562 | whose e_type member in the ELF header is not ET_DYN. There may |
| 2563 | be a time in the future when it is desirable to do relocations |
| 2564 | on other types of files as well in which case this condition |
| 2565 | should either be removed or modified to accomodate the new file |
| 2566 | type. - Kevin, Nov 2000. ] */ |
| 2567 | |
| 2568 | static int |
| 2569 | svr4_exec_displacement (CORE_ADDR *displacementp) |
| 2570 | { |
| 2571 | /* ENTRY_POINT is a possible function descriptor - before |
| 2572 | a call to gdbarch_convert_from_func_ptr_addr. */ |
| 2573 | CORE_ADDR entry_point, exec_displacement; |
| 2574 | |
| 2575 | if (current_program_space->exec_bfd () == NULL) |
| 2576 | return 0; |
| 2577 | |
| 2578 | /* Therefore for ELF it is ET_EXEC and not ET_DYN. Both shared libraries |
| 2579 | being executed themselves and PIE (Position Independent Executable) |
| 2580 | executables are ET_DYN. */ |
| 2581 | |
| 2582 | if ((bfd_get_file_flags (current_program_space->exec_bfd ()) & DYNAMIC) == 0) |
| 2583 | return 0; |
| 2584 | |
| 2585 | if (target_auxv_search (current_top_target (), AT_ENTRY, &entry_point) <= 0) |
| 2586 | return 0; |
| 2587 | |
| 2588 | exec_displacement |
| 2589 | = entry_point - bfd_get_start_address (current_program_space->exec_bfd ()); |
| 2590 | |
| 2591 | /* Verify the EXEC_DISPLACEMENT candidate complies with the required page |
| 2592 | alignment. It is cheaper than the program headers comparison below. */ |
| 2593 | |
| 2594 | if (bfd_get_flavour (current_program_space->exec_bfd ()) |
| 2595 | == bfd_target_elf_flavour) |
| 2596 | { |
| 2597 | const struct elf_backend_data *elf |
| 2598 | = get_elf_backend_data (current_program_space->exec_bfd ()); |
| 2599 | |
| 2600 | /* p_align of PT_LOAD segments does not specify any alignment but |
| 2601 | only congruency of addresses: |
| 2602 | p_offset % p_align == p_vaddr % p_align |
| 2603 | Kernel is free to load the executable with lower alignment. */ |
| 2604 | |
| 2605 | if ((exec_displacement & (elf->minpagesize - 1)) != 0) |
| 2606 | return 0; |
| 2607 | } |
| 2608 | |
| 2609 | /* Verify that the auxilliary vector describes the same file as exec_bfd, by |
| 2610 | comparing their program headers. If the program headers in the auxilliary |
| 2611 | vector do not match the program headers in the executable, then we are |
| 2612 | looking at a different file than the one used by the kernel - for |
| 2613 | instance, "gdb program" connected to "gdbserver :PORT ld.so program". */ |
| 2614 | |
| 2615 | if (bfd_get_flavour (current_program_space->exec_bfd ()) |
| 2616 | == bfd_target_elf_flavour) |
| 2617 | { |
| 2618 | /* Be optimistic and return 0 only if GDB was able to verify the headers |
| 2619 | really do not match. */ |
| 2620 | int arch_size; |
| 2621 | |
| 2622 | gdb::optional<gdb::byte_vector> phdrs_target |
| 2623 | = read_program_header (-1, &arch_size, NULL); |
| 2624 | gdb::optional<gdb::byte_vector> phdrs_binary |
| 2625 | = read_program_headers_from_bfd (current_program_space->exec_bfd ()); |
| 2626 | if (phdrs_target && phdrs_binary) |
| 2627 | { |
| 2628 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| 2629 | |
| 2630 | /* We are dealing with three different addresses. EXEC_BFD |
| 2631 | represents current address in on-disk file. target memory content |
| 2632 | may be different from EXEC_BFD as the file may have been prelinked |
| 2633 | to a different address after the executable has been loaded. |
| 2634 | Moreover the address of placement in target memory can be |
| 2635 | different from what the program headers in target memory say - |
| 2636 | this is the goal of PIE. |
| 2637 | |
| 2638 | Detected DISPLACEMENT covers both the offsets of PIE placement and |
| 2639 | possible new prelink performed after start of the program. Here |
| 2640 | relocate BUF and BUF2 just by the EXEC_BFD vs. target memory |
| 2641 | content offset for the verification purpose. */ |
| 2642 | |
| 2643 | if (phdrs_target->size () != phdrs_binary->size () |
| 2644 | || bfd_get_arch_size (current_program_space->exec_bfd ()) != arch_size) |
| 2645 | return 0; |
| 2646 | else if (arch_size == 32 |
| 2647 | && phdrs_target->size () >= sizeof (Elf32_External_Phdr) |
| 2648 | && phdrs_target->size () % sizeof (Elf32_External_Phdr) == 0) |
| 2649 | { |
| 2650 | Elf_Internal_Ehdr *ehdr2 |
| 2651 | = elf_tdata (current_program_space->exec_bfd ())->elf_header; |
| 2652 | Elf_Internal_Phdr *phdr2 |
| 2653 | = elf_tdata (current_program_space->exec_bfd ())->phdr; |
| 2654 | CORE_ADDR displacement = 0; |
| 2655 | int i; |
| 2656 | |
| 2657 | /* DISPLACEMENT could be found more easily by the difference of |
| 2658 | ehdr2->e_entry. But we haven't read the ehdr yet, and we |
| 2659 | already have enough information to compute that displacement |
| 2660 | with what we've read. */ |
| 2661 | |
| 2662 | for (i = 0; i < ehdr2->e_phnum; i++) |
| 2663 | if (phdr2[i].p_type == PT_LOAD) |
| 2664 | { |
| 2665 | Elf32_External_Phdr *phdrp; |
| 2666 | gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| 2667 | CORE_ADDR vaddr, paddr; |
| 2668 | CORE_ADDR displacement_vaddr = 0; |
| 2669 | CORE_ADDR displacement_paddr = 0; |
| 2670 | |
| 2671 | phdrp = &((Elf32_External_Phdr *) phdrs_target->data ())[i]; |
| 2672 | buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| 2673 | buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| 2674 | |
| 2675 | vaddr = extract_unsigned_integer (buf_vaddr_p, 4, |
| 2676 | byte_order); |
| 2677 | displacement_vaddr = vaddr - phdr2[i].p_vaddr; |
| 2678 | |
| 2679 | paddr = extract_unsigned_integer (buf_paddr_p, 4, |
| 2680 | byte_order); |
| 2681 | displacement_paddr = paddr - phdr2[i].p_paddr; |
| 2682 | |
| 2683 | if (displacement_vaddr == displacement_paddr) |
| 2684 | displacement = displacement_vaddr; |
| 2685 | |
| 2686 | break; |
| 2687 | } |
| 2688 | |
| 2689 | /* Now compare program headers from the target and the binary |
| 2690 | with optional DISPLACEMENT. */ |
| 2691 | |
| 2692 | for (i = 0; |
| 2693 | i < phdrs_target->size () / sizeof (Elf32_External_Phdr); |
| 2694 | i++) |
| 2695 | { |
| 2696 | Elf32_External_Phdr *phdrp; |
| 2697 | Elf32_External_Phdr *phdr2p; |
| 2698 | gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| 2699 | CORE_ADDR vaddr, paddr; |
| 2700 | asection *plt2_asect; |
| 2701 | |
| 2702 | phdrp = &((Elf32_External_Phdr *) phdrs_target->data ())[i]; |
| 2703 | buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| 2704 | buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| 2705 | phdr2p = &((Elf32_External_Phdr *) phdrs_binary->data ())[i]; |
| 2706 | |
| 2707 | /* PT_GNU_STACK is an exception by being never relocated by |
| 2708 | prelink as its addresses are always zero. */ |
| 2709 | |
| 2710 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 2711 | continue; |
| 2712 | |
| 2713 | /* Check also other adjustment combinations - PR 11786. */ |
| 2714 | |
| 2715 | vaddr = extract_unsigned_integer (buf_vaddr_p, 4, |
| 2716 | byte_order); |
| 2717 | vaddr -= displacement; |
| 2718 | store_unsigned_integer (buf_vaddr_p, 4, byte_order, vaddr); |
| 2719 | |
| 2720 | paddr = extract_unsigned_integer (buf_paddr_p, 4, |
| 2721 | byte_order); |
| 2722 | paddr -= displacement; |
| 2723 | store_unsigned_integer (buf_paddr_p, 4, byte_order, paddr); |
| 2724 | |
| 2725 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 2726 | continue; |
| 2727 | |
| 2728 | /* Strip modifies the flags and alignment of PT_GNU_RELRO. |
| 2729 | CentOS-5 has problems with filesz, memsz as well. |
| 2730 | Strip also modifies memsz of PT_TLS. |
| 2731 | See PR 11786. */ |
| 2732 | if (phdr2[i].p_type == PT_GNU_RELRO |
| 2733 | || phdr2[i].p_type == PT_TLS) |
| 2734 | { |
| 2735 | Elf32_External_Phdr tmp_phdr = *phdrp; |
| 2736 | Elf32_External_Phdr tmp_phdr2 = *phdr2p; |
| 2737 | |
| 2738 | memset (tmp_phdr.p_filesz, 0, 4); |
| 2739 | memset (tmp_phdr.p_memsz, 0, 4); |
| 2740 | memset (tmp_phdr.p_flags, 0, 4); |
| 2741 | memset (tmp_phdr.p_align, 0, 4); |
| 2742 | memset (tmp_phdr2.p_filesz, 0, 4); |
| 2743 | memset (tmp_phdr2.p_memsz, 0, 4); |
| 2744 | memset (tmp_phdr2.p_flags, 0, 4); |
| 2745 | memset (tmp_phdr2.p_align, 0, 4); |
| 2746 | |
| 2747 | if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr)) |
| 2748 | == 0) |
| 2749 | continue; |
| 2750 | } |
| 2751 | |
| 2752 | /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */ |
| 2753 | bfd *exec_bfd = current_program_space->exec_bfd (); |
| 2754 | plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt"); |
| 2755 | if (plt2_asect) |
| 2756 | { |
| 2757 | int content2; |
| 2758 | gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz; |
| 2759 | CORE_ADDR filesz; |
| 2760 | |
| 2761 | content2 = (bfd_section_flags (plt2_asect) |
| 2762 | & SEC_HAS_CONTENTS) != 0; |
| 2763 | |
| 2764 | filesz = extract_unsigned_integer (buf_filesz_p, 4, |
| 2765 | byte_order); |
| 2766 | |
| 2767 | /* PLT2_ASECT is from on-disk file (exec_bfd) while |
| 2768 | FILESZ is from the in-memory image. */ |
| 2769 | if (content2) |
| 2770 | filesz += bfd_section_size (plt2_asect); |
| 2771 | else |
| 2772 | filesz -= bfd_section_size (plt2_asect); |
| 2773 | |
| 2774 | store_unsigned_integer (buf_filesz_p, 4, byte_order, |
| 2775 | filesz); |
| 2776 | |
| 2777 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 2778 | continue; |
| 2779 | } |
| 2780 | |
| 2781 | return 0; |
| 2782 | } |
| 2783 | } |
| 2784 | else if (arch_size == 64 |
| 2785 | && phdrs_target->size () >= sizeof (Elf64_External_Phdr) |
| 2786 | && phdrs_target->size () % sizeof (Elf64_External_Phdr) == 0) |
| 2787 | { |
| 2788 | Elf_Internal_Ehdr *ehdr2 |
| 2789 | = elf_tdata (current_program_space->exec_bfd ())->elf_header; |
| 2790 | Elf_Internal_Phdr *phdr2 |
| 2791 | = elf_tdata (current_program_space->exec_bfd ())->phdr; |
| 2792 | CORE_ADDR displacement = 0; |
| 2793 | int i; |
| 2794 | |
| 2795 | /* DISPLACEMENT could be found more easily by the difference of |
| 2796 | ehdr2->e_entry. But we haven't read the ehdr yet, and we |
| 2797 | already have enough information to compute that displacement |
| 2798 | with what we've read. */ |
| 2799 | |
| 2800 | for (i = 0; i < ehdr2->e_phnum; i++) |
| 2801 | if (phdr2[i].p_type == PT_LOAD) |
| 2802 | { |
| 2803 | Elf64_External_Phdr *phdrp; |
| 2804 | gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| 2805 | CORE_ADDR vaddr, paddr; |
| 2806 | CORE_ADDR displacement_vaddr = 0; |
| 2807 | CORE_ADDR displacement_paddr = 0; |
| 2808 | |
| 2809 | phdrp = &((Elf64_External_Phdr *) phdrs_target->data ())[i]; |
| 2810 | buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| 2811 | buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| 2812 | |
| 2813 | vaddr = extract_unsigned_integer (buf_vaddr_p, 8, |
| 2814 | byte_order); |
| 2815 | displacement_vaddr = vaddr - phdr2[i].p_vaddr; |
| 2816 | |
| 2817 | paddr = extract_unsigned_integer (buf_paddr_p, 8, |
| 2818 | byte_order); |
| 2819 | displacement_paddr = paddr - phdr2[i].p_paddr; |
| 2820 | |
| 2821 | if (displacement_vaddr == displacement_paddr) |
| 2822 | displacement = displacement_vaddr; |
| 2823 | |
| 2824 | break; |
| 2825 | } |
| 2826 | |
| 2827 | /* Now compare BUF and BUF2 with optional DISPLACEMENT. */ |
| 2828 | |
| 2829 | for (i = 0; |
| 2830 | i < phdrs_target->size () / sizeof (Elf64_External_Phdr); |
| 2831 | i++) |
| 2832 | { |
| 2833 | Elf64_External_Phdr *phdrp; |
| 2834 | Elf64_External_Phdr *phdr2p; |
| 2835 | gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| 2836 | CORE_ADDR vaddr, paddr; |
| 2837 | asection *plt2_asect; |
| 2838 | |
| 2839 | phdrp = &((Elf64_External_Phdr *) phdrs_target->data ())[i]; |
| 2840 | buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| 2841 | buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| 2842 | phdr2p = &((Elf64_External_Phdr *) phdrs_binary->data ())[i]; |
| 2843 | |
| 2844 | /* PT_GNU_STACK is an exception by being never relocated by |
| 2845 | prelink as its addresses are always zero. */ |
| 2846 | |
| 2847 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 2848 | continue; |
| 2849 | |
| 2850 | /* Check also other adjustment combinations - PR 11786. */ |
| 2851 | |
| 2852 | vaddr = extract_unsigned_integer (buf_vaddr_p, 8, |
| 2853 | byte_order); |
| 2854 | vaddr -= displacement; |
| 2855 | store_unsigned_integer (buf_vaddr_p, 8, byte_order, vaddr); |
| 2856 | |
| 2857 | paddr = extract_unsigned_integer (buf_paddr_p, 8, |
| 2858 | byte_order); |
| 2859 | paddr -= displacement; |
| 2860 | store_unsigned_integer (buf_paddr_p, 8, byte_order, paddr); |
| 2861 | |
| 2862 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 2863 | continue; |
| 2864 | |
| 2865 | /* Strip modifies the flags and alignment of PT_GNU_RELRO. |
| 2866 | CentOS-5 has problems with filesz, memsz as well. |
| 2867 | Strip also modifies memsz of PT_TLS. |
| 2868 | See PR 11786. */ |
| 2869 | if (phdr2[i].p_type == PT_GNU_RELRO |
| 2870 | || phdr2[i].p_type == PT_TLS) |
| 2871 | { |
| 2872 | Elf64_External_Phdr tmp_phdr = *phdrp; |
| 2873 | Elf64_External_Phdr tmp_phdr2 = *phdr2p; |
| 2874 | |
| 2875 | memset (tmp_phdr.p_filesz, 0, 8); |
| 2876 | memset (tmp_phdr.p_memsz, 0, 8); |
| 2877 | memset (tmp_phdr.p_flags, 0, 4); |
| 2878 | memset (tmp_phdr.p_align, 0, 8); |
| 2879 | memset (tmp_phdr2.p_filesz, 0, 8); |
| 2880 | memset (tmp_phdr2.p_memsz, 0, 8); |
| 2881 | memset (tmp_phdr2.p_flags, 0, 4); |
| 2882 | memset (tmp_phdr2.p_align, 0, 8); |
| 2883 | |
| 2884 | if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr)) |
| 2885 | == 0) |
| 2886 | continue; |
| 2887 | } |
| 2888 | |
| 2889 | /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */ |
| 2890 | plt2_asect |
| 2891 | = bfd_get_section_by_name (current_program_space->exec_bfd (), |
| 2892 | ".plt"); |
| 2893 | if (plt2_asect) |
| 2894 | { |
| 2895 | int content2; |
| 2896 | gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz; |
| 2897 | CORE_ADDR filesz; |
| 2898 | |
| 2899 | content2 = (bfd_section_flags (plt2_asect) |
| 2900 | & SEC_HAS_CONTENTS) != 0; |
| 2901 | |
| 2902 | filesz = extract_unsigned_integer (buf_filesz_p, 8, |
| 2903 | byte_order); |
| 2904 | |
| 2905 | /* PLT2_ASECT is from on-disk file (current |
| 2906 | exec_bfd) while FILESZ is from the in-memory |
| 2907 | image. */ |
| 2908 | if (content2) |
| 2909 | filesz += bfd_section_size (plt2_asect); |
| 2910 | else |
| 2911 | filesz -= bfd_section_size (plt2_asect); |
| 2912 | |
| 2913 | store_unsigned_integer (buf_filesz_p, 8, byte_order, |
| 2914 | filesz); |
| 2915 | |
| 2916 | if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| 2917 | continue; |
| 2918 | } |
| 2919 | |
| 2920 | return 0; |
| 2921 | } |
| 2922 | } |
| 2923 | else |
| 2924 | return 0; |
| 2925 | } |
| 2926 | } |
| 2927 | |
| 2928 | if (info_verbose) |
| 2929 | { |
| 2930 | /* It can be printed repeatedly as there is no easy way to check |
| 2931 | the executable symbols/file has been already relocated to |
| 2932 | displacement. */ |
| 2933 | |
| 2934 | printf_unfiltered (_("Using PIE (Position Independent Executable) " |
| 2935 | "displacement %s for \"%s\".\n"), |
| 2936 | paddress (target_gdbarch (), exec_displacement), |
| 2937 | bfd_get_filename (current_program_space->exec_bfd ())); |
| 2938 | } |
| 2939 | |
| 2940 | *displacementp = exec_displacement; |
| 2941 | return 1; |
| 2942 | } |
| 2943 | |
| 2944 | /* Relocate the main executable. This function should be called upon |
| 2945 | stopping the inferior process at the entry point to the program. |
| 2946 | The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are |
| 2947 | different, the main executable is relocated by the proper amount. */ |
| 2948 | |
| 2949 | static void |
| 2950 | svr4_relocate_main_executable (void) |
| 2951 | { |
| 2952 | CORE_ADDR displacement; |
| 2953 | |
| 2954 | /* If we are re-running this executable, SYMFILE_OBJFILE->SECTION_OFFSETS |
| 2955 | probably contains the offsets computed using the PIE displacement |
| 2956 | from the previous run, which of course are irrelevant for this run. |
| 2957 | So we need to determine the new PIE displacement and recompute the |
| 2958 | section offsets accordingly, even if SYMFILE_OBJFILE->SECTION_OFFSETS |
| 2959 | already contains pre-computed offsets. |
| 2960 | |
| 2961 | If we cannot compute the PIE displacement, either: |
| 2962 | |
| 2963 | - The executable is not PIE. |
| 2964 | |
| 2965 | - SYMFILE_OBJFILE does not match the executable started in the target. |
| 2966 | This can happen for main executable symbols loaded at the host while |
| 2967 | `ld.so --ld-args main-executable' is loaded in the target. |
| 2968 | |
| 2969 | Then we leave the section offsets untouched and use them as is for |
| 2970 | this run. Either: |
| 2971 | |
| 2972 | - These section offsets were properly reset earlier, and thus |
| 2973 | already contain the correct values. This can happen for instance |
| 2974 | when reconnecting via the remote protocol to a target that supports |
| 2975 | the `qOffsets' packet. |
| 2976 | |
| 2977 | - The section offsets were not reset earlier, and the best we can |
| 2978 | hope is that the old offsets are still applicable to the new run. */ |
| 2979 | |
| 2980 | if (! svr4_exec_displacement (&displacement)) |
| 2981 | return; |
| 2982 | |
| 2983 | /* Even DISPLACEMENT 0 is a valid new difference of in-memory vs. in-file |
| 2984 | addresses. */ |
| 2985 | |
| 2986 | objfile *objf = current_program_space->symfile_object_file; |
| 2987 | if (objf) |
| 2988 | { |
| 2989 | section_offsets new_offsets (objf->section_offsets.size (), |
| 2990 | displacement); |
| 2991 | objfile_relocate (objf, new_offsets); |
| 2992 | } |
| 2993 | else if (current_program_space->exec_bfd ()) |
| 2994 | { |
| 2995 | asection *asect; |
| 2996 | |
| 2997 | bfd *exec_bfd = current_program_space->exec_bfd (); |
| 2998 | for (asect = exec_bfd->sections; asect != NULL; asect = asect->next) |
| 2999 | exec_set_section_address (bfd_get_filename (exec_bfd), asect->index, |
| 3000 | bfd_section_vma (asect) + displacement); |
| 3001 | } |
| 3002 | } |
| 3003 | |
| 3004 | /* Implement the "create_inferior_hook" target_solib_ops method. |
| 3005 | |
| 3006 | For SVR4 executables, this first instruction is either the first |
| 3007 | instruction in the dynamic linker (for dynamically linked |
| 3008 | executables) or the instruction at "start" for statically linked |
| 3009 | executables. For dynamically linked executables, the system |
| 3010 | first exec's /lib/libc.so.N, which contains the dynamic linker, |
| 3011 | and starts it running. The dynamic linker maps in any needed |
| 3012 | shared libraries, maps in the actual user executable, and then |
| 3013 | jumps to "start" in the user executable. |
| 3014 | |
| 3015 | We can arrange to cooperate with the dynamic linker to discover the |
| 3016 | names of shared libraries that are dynamically linked, and the base |
| 3017 | addresses to which they are linked. |
| 3018 | |
| 3019 | This function is responsible for discovering those names and |
| 3020 | addresses, and saving sufficient information about them to allow |
| 3021 | their symbols to be read at a later time. */ |
| 3022 | |
| 3023 | static void |
| 3024 | svr4_solib_create_inferior_hook (int from_tty) |
| 3025 | { |
| 3026 | struct svr4_info *info; |
| 3027 | |
| 3028 | info = get_svr4_info (current_program_space); |
| 3029 | |
| 3030 | /* Clear the probes-based interface's state. */ |
| 3031 | free_probes_table (info); |
| 3032 | free_solib_list (info); |
| 3033 | |
| 3034 | /* Relocate the main executable if necessary. */ |
| 3035 | svr4_relocate_main_executable (); |
| 3036 | |
| 3037 | /* No point setting a breakpoint in the dynamic linker if we can't |
| 3038 | hit it (e.g., a core file, or a trace file). */ |
| 3039 | if (!target_has_execution ()) |
| 3040 | return; |
| 3041 | |
| 3042 | if (!svr4_have_link_map_offsets ()) |
| 3043 | return; |
| 3044 | |
| 3045 | if (!enable_break (info, from_tty)) |
| 3046 | return; |
| 3047 | } |
| 3048 | |
| 3049 | static void |
| 3050 | svr4_clear_solib (void) |
| 3051 | { |
| 3052 | struct svr4_info *info; |
| 3053 | |
| 3054 | info = get_svr4_info (current_program_space); |
| 3055 | info->debug_base = 0; |
| 3056 | info->debug_loader_offset_p = 0; |
| 3057 | info->debug_loader_offset = 0; |
| 3058 | xfree (info->debug_loader_name); |
| 3059 | info->debug_loader_name = NULL; |
| 3060 | } |
| 3061 | |
| 3062 | /* Clear any bits of ADDR that wouldn't fit in a target-format |
| 3063 | data pointer. "Data pointer" here refers to whatever sort of |
| 3064 | address the dynamic linker uses to manage its sections. At the |
| 3065 | moment, we don't support shared libraries on any processors where |
| 3066 | code and data pointers are different sizes. |
| 3067 | |
| 3068 | This isn't really the right solution. What we really need here is |
| 3069 | a way to do arithmetic on CORE_ADDR values that respects the |
| 3070 | natural pointer/address correspondence. (For example, on the MIPS, |
| 3071 | converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to |
| 3072 | sign-extend the value. There, simply truncating the bits above |
| 3073 | gdbarch_ptr_bit, as we do below, is no good.) This should probably |
| 3074 | be a new gdbarch method or something. */ |
| 3075 | static CORE_ADDR |
| 3076 | svr4_truncate_ptr (CORE_ADDR addr) |
| 3077 | { |
| 3078 | if (gdbarch_ptr_bit (target_gdbarch ()) == sizeof (CORE_ADDR) * 8) |
| 3079 | /* We don't need to truncate anything, and the bit twiddling below |
| 3080 | will fail due to overflow problems. */ |
| 3081 | return addr; |
| 3082 | else |
| 3083 | return addr & (((CORE_ADDR) 1 << gdbarch_ptr_bit (target_gdbarch ())) - 1); |
| 3084 | } |
| 3085 | |
| 3086 | |
| 3087 | static void |
| 3088 | svr4_relocate_section_addresses (struct so_list *so, |
| 3089 | struct target_section *sec) |
| 3090 | { |
| 3091 | bfd *abfd = sec->the_bfd_section->owner; |
| 3092 | |
| 3093 | sec->addr = svr4_truncate_ptr (sec->addr + lm_addr_check (so, abfd)); |
| 3094 | sec->endaddr = svr4_truncate_ptr (sec->endaddr + lm_addr_check (so, abfd)); |
| 3095 | } |
| 3096 | \f |
| 3097 | |
| 3098 | /* Architecture-specific operations. */ |
| 3099 | |
| 3100 | /* Per-architecture data key. */ |
| 3101 | static struct gdbarch_data *solib_svr4_data; |
| 3102 | |
| 3103 | struct solib_svr4_ops |
| 3104 | { |
| 3105 | /* Return a description of the layout of `struct link_map'. */ |
| 3106 | struct link_map_offsets *(*fetch_link_map_offsets)(void); |
| 3107 | }; |
| 3108 | |
| 3109 | /* Return a default for the architecture-specific operations. */ |
| 3110 | |
| 3111 | static void * |
| 3112 | solib_svr4_init (struct obstack *obstack) |
| 3113 | { |
| 3114 | struct solib_svr4_ops *ops; |
| 3115 | |
| 3116 | ops = OBSTACK_ZALLOC (obstack, struct solib_svr4_ops); |
| 3117 | ops->fetch_link_map_offsets = NULL; |
| 3118 | return ops; |
| 3119 | } |
| 3120 | |
| 3121 | /* Set the architecture-specific `struct link_map_offsets' fetcher for |
| 3122 | GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */ |
| 3123 | |
| 3124 | void |
| 3125 | set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch, |
| 3126 | struct link_map_offsets *(*flmo) (void)) |
| 3127 | { |
| 3128 | struct solib_svr4_ops *ops |
| 3129 | = (struct solib_svr4_ops *) gdbarch_data (gdbarch, solib_svr4_data); |
| 3130 | |
| 3131 | ops->fetch_link_map_offsets = flmo; |
| 3132 | |
| 3133 | set_solib_ops (gdbarch, &svr4_so_ops); |
| 3134 | set_gdbarch_iterate_over_objfiles_in_search_order |
| 3135 | (gdbarch, svr4_iterate_over_objfiles_in_search_order); |
| 3136 | } |
| 3137 | |
| 3138 | /* Fetch a link_map_offsets structure using the architecture-specific |
| 3139 | `struct link_map_offsets' fetcher. */ |
| 3140 | |
| 3141 | static struct link_map_offsets * |
| 3142 | svr4_fetch_link_map_offsets (void) |
| 3143 | { |
| 3144 | struct solib_svr4_ops *ops |
| 3145 | = (struct solib_svr4_ops *) gdbarch_data (target_gdbarch (), |
| 3146 | solib_svr4_data); |
| 3147 | |
| 3148 | gdb_assert (ops->fetch_link_map_offsets); |
| 3149 | return ops->fetch_link_map_offsets (); |
| 3150 | } |
| 3151 | |
| 3152 | /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */ |
| 3153 | |
| 3154 | static int |
| 3155 | svr4_have_link_map_offsets (void) |
| 3156 | { |
| 3157 | struct solib_svr4_ops *ops |
| 3158 | = (struct solib_svr4_ops *) gdbarch_data (target_gdbarch (), |
| 3159 | solib_svr4_data); |
| 3160 | |
| 3161 | return (ops->fetch_link_map_offsets != NULL); |
| 3162 | } |
| 3163 | \f |
| 3164 | |
| 3165 | /* Most OS'es that have SVR4-style ELF dynamic libraries define a |
| 3166 | `struct r_debug' and a `struct link_map' that are binary compatible |
| 3167 | with the original SVR4 implementation. */ |
| 3168 | |
| 3169 | /* Fetch (and possibly build) an appropriate `struct link_map_offsets' |
| 3170 | for an ILP32 SVR4 system. */ |
| 3171 | |
| 3172 | struct link_map_offsets * |
| 3173 | svr4_ilp32_fetch_link_map_offsets (void) |
| 3174 | { |
| 3175 | static struct link_map_offsets lmo; |
| 3176 | static struct link_map_offsets *lmp = NULL; |
| 3177 | |
| 3178 | if (lmp == NULL) |
| 3179 | { |
| 3180 | lmp = &lmo; |
| 3181 | |
| 3182 | lmo.r_version_offset = 0; |
| 3183 | lmo.r_version_size = 4; |
| 3184 | lmo.r_map_offset = 4; |
| 3185 | lmo.r_brk_offset = 8; |
| 3186 | lmo.r_ldsomap_offset = 20; |
| 3187 | |
| 3188 | /* Everything we need is in the first 20 bytes. */ |
| 3189 | lmo.link_map_size = 20; |
| 3190 | lmo.l_addr_offset = 0; |
| 3191 | lmo.l_name_offset = 4; |
| 3192 | lmo.l_ld_offset = 8; |
| 3193 | lmo.l_next_offset = 12; |
| 3194 | lmo.l_prev_offset = 16; |
| 3195 | } |
| 3196 | |
| 3197 | return lmp; |
| 3198 | } |
| 3199 | |
| 3200 | /* Fetch (and possibly build) an appropriate `struct link_map_offsets' |
| 3201 | for an LP64 SVR4 system. */ |
| 3202 | |
| 3203 | struct link_map_offsets * |
| 3204 | svr4_lp64_fetch_link_map_offsets (void) |
| 3205 | { |
| 3206 | static struct link_map_offsets lmo; |
| 3207 | static struct link_map_offsets *lmp = NULL; |
| 3208 | |
| 3209 | if (lmp == NULL) |
| 3210 | { |
| 3211 | lmp = &lmo; |
| 3212 | |
| 3213 | lmo.r_version_offset = 0; |
| 3214 | lmo.r_version_size = 4; |
| 3215 | lmo.r_map_offset = 8; |
| 3216 | lmo.r_brk_offset = 16; |
| 3217 | lmo.r_ldsomap_offset = 40; |
| 3218 | |
| 3219 | /* Everything we need is in the first 40 bytes. */ |
| 3220 | lmo.link_map_size = 40; |
| 3221 | lmo.l_addr_offset = 0; |
| 3222 | lmo.l_name_offset = 8; |
| 3223 | lmo.l_ld_offset = 16; |
| 3224 | lmo.l_next_offset = 24; |
| 3225 | lmo.l_prev_offset = 32; |
| 3226 | } |
| 3227 | |
| 3228 | return lmp; |
| 3229 | } |
| 3230 | \f |
| 3231 | |
| 3232 | struct target_so_ops svr4_so_ops; |
| 3233 | |
| 3234 | /* Search order for ELF DSOs linked with -Bsymbolic. Those DSOs have a |
| 3235 | different rule for symbol lookup. The lookup begins here in the DSO, not in |
| 3236 | the main executable. */ |
| 3237 | |
| 3238 | static void |
| 3239 | svr4_iterate_over_objfiles_in_search_order |
| 3240 | (struct gdbarch *gdbarch, |
| 3241 | iterate_over_objfiles_in_search_order_cb_ftype *cb, |
| 3242 | void *cb_data, struct objfile *current_objfile) |
| 3243 | { |
| 3244 | bool checked_current_objfile = false; |
| 3245 | if (current_objfile != nullptr) |
| 3246 | { |
| 3247 | bfd *abfd; |
| 3248 | |
| 3249 | if (current_objfile->separate_debug_objfile_backlink != nullptr) |
| 3250 | current_objfile = current_objfile->separate_debug_objfile_backlink; |
| 3251 | |
| 3252 | if (current_objfile == current_program_space->symfile_object_file) |
| 3253 | abfd = current_program_space->exec_bfd (); |
| 3254 | else |
| 3255 | abfd = current_objfile->obfd; |
| 3256 | |
| 3257 | if (abfd != nullptr |
| 3258 | && scan_dyntag (DT_SYMBOLIC, abfd, nullptr, nullptr) == 1) |
| 3259 | { |
| 3260 | checked_current_objfile = true; |
| 3261 | if (cb (current_objfile, cb_data) != 0) |
| 3262 | return; |
| 3263 | } |
| 3264 | } |
| 3265 | |
| 3266 | for (objfile *objfile : current_program_space->objfiles ()) |
| 3267 | { |
| 3268 | if (checked_current_objfile && objfile == current_objfile) |
| 3269 | continue; |
| 3270 | if (cb (objfile, cb_data) != 0) |
| 3271 | return; |
| 3272 | } |
| 3273 | } |
| 3274 | |
| 3275 | void _initialize_svr4_solib (); |
| 3276 | void |
| 3277 | _initialize_svr4_solib () |
| 3278 | { |
| 3279 | solib_svr4_data = gdbarch_data_register_pre_init (solib_svr4_init); |
| 3280 | |
| 3281 | svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses; |
| 3282 | svr4_so_ops.free_so = svr4_free_so; |
| 3283 | svr4_so_ops.clear_so = svr4_clear_so; |
| 3284 | svr4_so_ops.clear_solib = svr4_clear_solib; |
| 3285 | svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook; |
| 3286 | svr4_so_ops.current_sos = svr4_current_sos; |
| 3287 | svr4_so_ops.open_symbol_file_object = open_symbol_file_object; |
| 3288 | svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code; |
| 3289 | svr4_so_ops.bfd_open = solib_bfd_open; |
| 3290 | svr4_so_ops.same = svr4_same; |
| 3291 | svr4_so_ops.keep_data_in_core = svr4_keep_data_in_core; |
| 3292 | svr4_so_ops.update_breakpoints = svr4_update_solib_event_breakpoints; |
| 3293 | svr4_so_ops.handle_event = svr4_handle_solib_event; |
| 3294 | |
| 3295 | gdb::observers::free_objfile.attach (svr4_free_objfile_observer); |
| 3296 | } |