solib-osf.c revision 98944
1/* Handle OSF/1, Digital UNIX, and Tru64 shared libraries 2 for GDB, the GNU Debugger. 3 Copyright 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001 4 Free Software Foundation, Inc. 5 6 This file is part of GDB. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 2 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program; if not, write to the Free Software 20 Foundation, Inc., 59 Temple Place - Suite 330, 21 Boston, MA 02111-1307, USA. */ 22 23/* When handling shared libraries, GDB has to find out the pathnames 24 of all shared libraries that are currently loaded (to read in their 25 symbols) and where the shared libraries are loaded in memory 26 (to relocate them properly from their prelinked addresses to the 27 current load address). 28 29 Under OSF/1 there are two possibilities to get at this information: 30 31 1) Peek around in the runtime loader structures. 32 These are not documented, and they are not defined in the system 33 header files. The definitions below were obtained by experimentation, 34 but they seem stable enough. 35 36 2) Use the libxproc.a library, which contains the equivalent ldr_* 37 routines. The library is documented in Tru64 5.x, but as of 5.1, it 38 only allows a process to examine itself. On earlier versions, it 39 may require that the GDB executable be dynamically linked and that 40 NAT_CLIBS include -lxproc -Wl,-expect_unresolved,ldr_process_context 41 for GDB and all applications that are using libgdb. 42 43 We will use the peeking approach until libxproc.a works for other 44 processes. */ 45 46#include "defs.h" 47 48#include <sys/types.h> 49#include <signal.h> 50#include "gdb_string.h" 51 52#include "bfd.h" 53#include "symtab.h" 54#include "symfile.h" 55#include "objfiles.h" 56#include "target.h" 57#include "inferior.h" 58#include "solist.h" 59 60#ifdef USE_LDR_ROUTINES 61# include <loader.h> 62#endif 63 64#ifndef USE_LDR_ROUTINES 65/* Definition of runtime loader structures, found by experimentation. */ 66#define RLD_CONTEXT_ADDRESS 0x3ffc0000000 67 68/* Per-module information structure referenced by ldr_context_t.head. */ 69 70typedef struct 71 { 72 CORE_ADDR next; 73 CORE_ADDR previous; 74 CORE_ADDR unknown1; 75 CORE_ADDR module_name; 76 CORE_ADDR modinfo_addr; /* used by next_link_map_member() to detect 77 the end of the shared module list */ 78 long module_id; 79 CORE_ADDR unknown2; 80 CORE_ADDR unknown3; 81 long region_count; 82 CORE_ADDR regioninfo_addr; 83 } 84ldr_module_info_t; 85 86/* Per-region structure referenced by ldr_module_info_t.regioninfo_addr. */ 87 88typedef struct 89 { 90 long unknown1; 91 CORE_ADDR regionname_addr; 92 long protection; 93 CORE_ADDR vaddr; 94 CORE_ADDR mapaddr; 95 long size; 96 long unknown2[5]; 97 } 98ldr_region_info_t; 99 100/* Structure at RLD_CONTEXT_ADDRESS specifying the start and finish addresses 101 of the shared module list. */ 102 103typedef struct 104 { 105 CORE_ADDR unknown1; 106 CORE_ADDR unknown2; 107 CORE_ADDR head; 108 CORE_ADDR tail; 109 } 110ldr_context_t; 111#endif /* !USE_LDR_ROUTINES */ 112 113/* Per-section information, stored in struct lm_info.secs. */ 114 115struct lm_sec 116 { 117 CORE_ADDR offset; /* difference between default and actual 118 virtual addresses of section .name */ 119 CORE_ADDR nameaddr; /* address in inferior of section name */ 120 const char *name; /* name of section, null if not fetched */ 121 }; 122 123/* Per-module information, stored in struct so_list.lm_info. */ 124 125struct lm_info 126 { 127 int isloader; /* whether the module is /sbin/loader */ 128 int nsecs; /* length of .secs */ 129 struct lm_sec secs[1]; /* variable-length array of sections, sorted 130 by name */ 131 }; 132 133/* Context for iterating through the inferior's shared module list. */ 134 135struct read_map_ctxt 136 { 137#ifdef USE_LDR_ROUTINES 138 ldr_process_t proc; 139 ldr_module_t next; 140#else 141 CORE_ADDR next; /* next element in module list */ 142 CORE_ADDR tail; /* last element in module list */ 143#endif 144 }; 145 146/* Forward declaration for this module's autoinit function. */ 147 148extern void _initialize_osf_solib (void); 149 150#ifdef USE_LDR_ROUTINES 151# if 0 152/* This routine is intended to be called by ldr_* routines to read memory from 153 the current target. Usage: 154 155 ldr_process = ldr_core_process (); 156 ldr_set_core_reader (ldr_read_memory); 157 ldr_xdetach (ldr_process); 158 ldr_xattach (ldr_process); 159 160 ldr_core_process() and ldr_read_memory() are neither documented nor 161 declared in system header files. They work with OSF/1 2.x, and they might 162 work with later versions as well. */ 163 164static int 165ldr_read_memory (CORE_ADDR memaddr, char *myaddr, int len, int readstring) 166{ 167 int result; 168 char *buffer; 169 170 if (readstring) 171 { 172 target_read_string (memaddr, &buffer, len, &result); 173 if (result == 0) 174 strcpy (myaddr, buffer); 175 xfree (buffer); 176 } 177 else 178 result = target_read_memory (memaddr, myaddr, len); 179 180 if (result != 0) 181 result = -result; 182 return result; 183} 184# endif /* 0 */ 185#endif /* USE_LDR_ROUTINES */ 186 187/* Comparison for qsort() and bsearch(): return -1, 0, or 1 according to 188 whether lm_sec *P1's name is lexically less than, equal to, or greater 189 than that of *P2. */ 190 191static int 192lm_sec_cmp (const void *p1, const void *p2) 193{ 194 const struct lm_sec *lms1 = p1, *lms2 = p2; 195 return strcmp (lms1->name, lms2->name); 196} 197 198/* Sort LMI->secs so that osf_relocate_section_addresses() can binary-search 199 it. */ 200 201static void 202lm_secs_sort (struct lm_info *lmi) 203{ 204 qsort (lmi->secs, lmi->nsecs, sizeof *lmi->secs, lm_sec_cmp); 205} 206 207/* Populate name fields of LMI->secs. */ 208 209static void 210fetch_sec_names (struct lm_info *lmi) 211{ 212#ifndef USE_LDR_ROUTINES 213 int i, errcode; 214 struct lm_sec *lms; 215 char *name; 216 217 for (i = 0; i < lmi->nsecs; i++) 218 { 219 lms = lmi->secs + i; 220 target_read_string (lms->nameaddr, &name, PATH_MAX, &errcode); 221 if (errcode != 0) 222 { 223 warning ("unable to read shared sec name at 0x%lx", lms->nameaddr); 224 name = xstrdup (""); 225 } 226 lms->name = name; 227 } 228 lm_secs_sort (lmi); 229#endif 230} 231 232/* target_so_ops callback. Adjust SEC's addresses after it's been mapped into 233 the process. */ 234 235static void 236osf_relocate_section_addresses (struct so_list *so, 237 struct section_table *sec) 238{ 239 struct lm_info *lmi; 240 struct lm_sec lms_key, *lms; 241 242 /* Fetch SO's section names if we haven't done so already. */ 243 lmi = so->lm_info; 244 if (lmi->nsecs && !lmi->secs[0].name) 245 fetch_sec_names (lmi); 246 247 /* Binary-search for offset information corresponding to SEC. */ 248 lms_key.name = sec->the_bfd_section->name; 249 lms = bsearch (&lms_key, lmi->secs, lmi->nsecs, sizeof *lms, lm_sec_cmp); 250 if (lms) 251 { 252 sec->addr += lms->offset; 253 sec->endaddr += lms->offset; 254 } 255} 256 257/* target_so_ops callback. Free parts of SO allocated by this file. */ 258 259static void 260osf_free_so (struct so_list *so) 261{ 262 int i; 263 const char *name; 264 265 for (i = 0; i < so->lm_info->nsecs; i++) 266 { 267 name = so->lm_info->secs[i].name; 268 if (name) 269 xfree ((void *) name); 270 } 271 xfree (so->lm_info); 272} 273 274/* target_so_ops callback. Discard information accumulated by this file and 275 not freed by osf_free_so(). */ 276 277static void 278osf_clear_solib (void) 279{ 280 return; 281} 282 283/* target_so_ops callback. Prepare to handle shared libraries after the 284 inferior process has been created but before it's executed any 285 instructions. 286 287 For a statically bound executable, the inferior's first instruction is the 288 one at "_start", or a similar text label. No further processing is needed 289 in that case. 290 291 For a dynamically bound executable, this first instruction is somewhere 292 in the rld, and the actual user executable is not yet mapped in. 293 We continue the inferior again, rld then maps in the actual user 294 executable and any needed shared libraries and then sends 295 itself a SIGTRAP. 296 297 At that point we discover the names of all shared libraries and 298 read their symbols in. 299 300 FIXME 301 302 This code does not properly handle hitting breakpoints which the 303 user might have set in the rld itself. Proper handling would have 304 to check if the SIGTRAP happened due to a kill call. 305 306 Also, what if child has exit()ed? Must exit loop somehow. */ 307 308static void 309osf_solib_create_inferior_hook (void) 310{ 311 /* Nothing to do for statically bound executables. */ 312 313 if (symfile_objfile == NULL 314 || symfile_objfile->obfd == NULL 315 || ((bfd_get_file_flags (symfile_objfile->obfd) & DYNAMIC) == 0)) 316 return; 317 318 /* Now run the target. It will eventually get a SIGTRAP, at 319 which point all of the libraries will have been mapped in and we 320 can go groveling around in the rld structures to find 321 out what we need to know about them. */ 322 323 clear_proceed_status (); 324 stop_soon_quietly = 1; 325 stop_signal = TARGET_SIGNAL_0; 326 do 327 { 328 target_resume (minus_one_ptid, 0, stop_signal); 329 wait_for_inferior (); 330 } 331 while (stop_signal != TARGET_SIGNAL_TRAP); 332 333 /* solib_add will call reinit_frame_cache. 334 But we are stopped in the runtime loader and we do not have symbols 335 for the runtime loader. So heuristic_proc_start will be called 336 and will put out an annoying warning. 337 Delaying the resetting of stop_soon_quietly until after symbol loading 338 suppresses the warning. */ 339 solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add); 340 stop_soon_quietly = 0; 341 342 /* Enable breakpoints disabled (unnecessarily) by clear_solib(). */ 343 re_enable_breakpoints_in_shlibs (); 344} 345 346/* target_so_ops callback. Do additional symbol handling, lookup, etc. after 347 symbols for a shared object have been loaded. */ 348 349static void 350osf_special_symbol_handling (void) 351{ 352 return; 353} 354 355/* Initialize CTXT in preparation for iterating through the inferior's module 356 list using read_map(). Return success. */ 357 358static int 359open_map (struct read_map_ctxt *ctxt) 360{ 361#ifdef USE_LDR_ROUTINES 362 ctxt->proc = ldr_my_process (); 363 if (ldr_xattach (ctxt->proc) != 0) 364 return 0; 365 ctxt->next = LDR_NULL_MODULE; 366#else 367 CORE_ADDR ldr_context_addr, prev, next; 368 ldr_context_t ldr_context; 369 370 if (target_read_memory ((CORE_ADDR) RLD_CONTEXT_ADDRESS, 371 (char *) &ldr_context_addr, 372 sizeof (CORE_ADDR)) != 0) 373 return 0; 374 if (target_read_memory (ldr_context_addr, 375 (char *) &ldr_context, 376 sizeof (ldr_context_t)) != 0) 377 return 0; 378 ctxt->next = ldr_context.head; 379 ctxt->tail = ldr_context.tail; 380#endif 381 return 1; 382} 383 384/* Initialize SO to have module NAME, /sbin/loader indicator ISLOADR, and 385 space for NSECS sections. */ 386 387static void 388init_so (struct so_list *so, char *name, int isloader, int nsecs) 389{ 390 int namelen, i; 391 392 /* solib.c requires various fields to be initialized to 0. */ 393 memset (so, 0, sizeof *so); 394 395 /* Copy the name. */ 396 namelen = strlen (name); 397 if (namelen >= SO_NAME_MAX_PATH_SIZE) 398 namelen = SO_NAME_MAX_PATH_SIZE - 1; 399 400 memcpy (so->so_original_name, name, namelen); 401 so->so_original_name[namelen] = '\0'; 402 memcpy (so->so_name, so->so_original_name, namelen + 1); 403 404 /* Allocate section space. */ 405 so->lm_info = xmalloc ((unsigned) &(((struct lm_info *)0)->secs) + 406 nsecs * sizeof *so->lm_info); 407 so->lm_info->isloader = isloader; 408 so->lm_info->nsecs = nsecs; 409 for (i = 0; i < nsecs; i++) 410 so->lm_info->secs[i].name = NULL; 411} 412 413/* Initialize SO's section SECIDX with name address NAMEADDR, name string 414 NAME, default virtual address VADDR, and actual virtual address 415 MAPADDR. */ 416 417static void 418init_sec (struct so_list *so, int secidx, CORE_ADDR nameaddr, 419 const char *name, CORE_ADDR vaddr, CORE_ADDR mapaddr) 420{ 421 struct lm_sec *lms; 422 423 lms = so->lm_info->secs + secidx; 424 lms->nameaddr = nameaddr; 425 lms->name = name; 426 lms->offset = mapaddr - vaddr; 427} 428 429/* If there are more elements starting at CTXT in inferior's module list, 430 store the next element in SO, advance CTXT to the next element, and return 431 1, else return 0. */ 432 433static int 434read_map (struct read_map_ctxt *ctxt, struct so_list *so) 435{ 436 ldr_module_info_t minf; 437 ldr_region_info_t rinf; 438 439#ifdef USE_LDR_ROUTINES 440 size_t size; 441 ldr_region_t i; 442 443 /* Retrieve the next element. */ 444 if (ldr_next_module (ctxt->proc, &ctxt->next) != 0) 445 return 0; 446 if (ctxt->next == LDR_NULL_MODULE) 447 return 0; 448 if (ldr_inq_module (ctxt->proc, ctxt->next, &minf, sizeof minf, &size) != 0) 449 return 0; 450 451 /* Initialize the module name and section count. */ 452 init_so (so, minf.lmi_name, 0, minf.lmi_nregion); 453 454 /* Retrieve section names and offsets. */ 455 for (i = 0; i < minf.lmi_nregion; i++) 456 { 457 if (ldr_inq_region (ctxt->proc, ctxt->next, i, &rinf, 458 sizeof rinf, &size) != 0) 459 goto err; 460 init_sec (so, (int) i, 0, xstrdup (rinf.lri_name), 461 (CORE_ADDR) rinf.lri_vaddr, (CORE_ADDR) rinf.lri_mapaddr); 462 } 463 lm_secs_sort (so->lm_info); 464#else 465 char *name; 466 int errcode, i; 467 468 /* Retrieve the next element. */ 469 if (!ctxt->next) 470 return 0; 471 if (target_read_memory (ctxt->next, (char *) &minf, sizeof minf) != 0) 472 return 0; 473 if (ctxt->next == ctxt->tail) 474 ctxt->next = 0; 475 else 476 ctxt->next = minf.next; 477 478 /* Initialize the module name and section count. */ 479 target_read_string (minf.module_name, &name, PATH_MAX, &errcode); 480 if (errcode != 0) 481 return 0; 482 init_so (so, name, !minf.modinfo_addr, minf.region_count); 483 xfree (name); 484 485 /* Retrieve section names and offsets. */ 486 for (i = 0; i < minf.region_count; i++) 487 { 488 if (target_read_memory (minf.regioninfo_addr + i * sizeof rinf, 489 (char *) &rinf, sizeof rinf) != 0) 490 goto err; 491 init_sec (so, i, rinf.regionname_addr, NULL, rinf.vaddr, rinf.mapaddr); 492 } 493#endif /* !USE_LDR_ROUTINES */ 494 return 1; 495 496 err: 497 osf_free_so (so); 498 return 0; 499} 500 501/* Free resources allocated by open_map (CTXT). */ 502 503static void 504close_map (struct read_map_ctxt *ctxt) 505{ 506#ifdef USE_LDR_ROUTINES 507 ldr_xdetach (ctxt->proc); 508#endif 509} 510 511/* target_so_ops callback. Return a list of shared objects currently loaded 512 in the inferior. */ 513 514static struct so_list * 515osf_current_sos (void) 516{ 517 struct so_list *head = NULL, *tail, *newtail, so; 518 struct read_map_ctxt ctxt; 519 int skipped_main; 520 521 if (!open_map (&ctxt)) 522 return NULL; 523 524 /* Read subsequent elements. */ 525 for (skipped_main = 0;;) 526 { 527 if (!read_map (&ctxt, &so)) 528 break; 529 530 /* Skip the main program module, which is first in the list after 531 /sbin/loader. */ 532 if (!so.lm_info->isloader && !skipped_main) 533 { 534 osf_free_so (&so); 535 skipped_main = 1; 536 continue; 537 } 538 539 newtail = xmalloc (sizeof *newtail); 540 if (!head) 541 head = newtail; 542 else 543 tail->next = newtail; 544 tail = newtail; 545 546 memcpy (tail, &so, sizeof so); 547 tail->next = NULL; 548 } 549 550 done: 551 close_map (&ctxt); 552 return head; 553} 554 555/* target_so_ops callback. Attempt to locate and open the main symbol 556 file. */ 557 558static int 559osf_open_symbol_file_object (void *from_ttyp) 560{ 561 struct read_map_ctxt ctxt; 562 struct so_list so; 563 int found; 564 565 if (symfile_objfile) 566 if (!query ("Attempt to reload symbols from process? ")) 567 return 0; 568 569 /* The first module after /sbin/loader is the main program. */ 570 if (!open_map (&ctxt)) 571 return 0; 572 for (found = 0; !found;) 573 { 574 if (!read_map (&ctxt, &so)) 575 break; 576 found = !so.lm_info->isloader; 577 osf_free_so (&so); 578 } 579 close_map (&ctxt); 580 581 if (found) 582 symbol_file_add_main (so.so_name, *(int *) from_ttyp); 583 return found; 584} 585 586/* target_so_ops callback. Return whether PC is in the dynamic linker. */ 587 588static int 589osf_in_dynsym_resolve_code (CORE_ADDR pc) 590{ 591 /* This function currently always return False. This is a temporary 592 solution which only consequence is to introduce a minor incovenience 593 for the user: When stepping inside a subprogram located in a shared 594 library, gdb might stop inside the dynamic loader code instead of 595 inside the subprogram itself. See the explanations in infrun.c about 596 the IN_SOLIB_DYNSYM_RESOLVE_CODE macro for more details. */ 597 return 0; 598} 599 600static struct target_so_ops osf_so_ops; 601 602void 603_initialize_osf_solib (void) 604{ 605 osf_so_ops.relocate_section_addresses = osf_relocate_section_addresses; 606 osf_so_ops.free_so = osf_free_so; 607 osf_so_ops.clear_solib = osf_clear_solib; 608 osf_so_ops.solib_create_inferior_hook = osf_solib_create_inferior_hook; 609 osf_so_ops.special_symbol_handling = osf_special_symbol_handling; 610 osf_so_ops.current_sos = osf_current_sos; 611 osf_so_ops.open_symbol_file_object = osf_open_symbol_file_object; 612 osf_so_ops.in_dynsym_resolve_code = osf_in_dynsym_resolve_code; 613 614 /* FIXME: Don't do this here. *_gdbarch_init() should set so_ops. */ 615 current_target_so_ops = &osf_so_ops; 616} 617