gdb/solib-osf.c

   1 /* Handle OSF/1, Digital UNIX, and Tru64 shared libraries
   2    for GDB, the GNU Debugger.
   3    Copyright (C) 1993-2013 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 /* When handling shared libraries, GDB has to find out the pathnames
  21    of all shared libraries that are currently loaded (to read in their
  22    symbols) and where the shared libraries are loaded in memory
  23    (to relocate them properly from their prelinked addresses to the
  24    current load address).
  25
  26    Under OSF/1 there are two possibilities to get at this information:
  27
  28    1) Peek around in the runtime loader structures.
  29    These are not documented, and they are not defined in the system
  30    header files.  The definitions below were obtained by experimentation,
  31    but they seem stable enough.
  32
  33    2) Use the libxproc.a library, which contains the equivalent ldr_*
  34    routines.  The library is documented in Tru64 5.x, but as of 5.1, it
  35    only allows a process to examine itself.  On earlier versions, it
  36    may require that the GDB executable be dynamically linked and that
  37    NAT_CLIBS include -lxproc -Wl,-expect_unresolved,ldr_process_context
  38    for GDB and all applications that are using libgdb.
  39
  40    We will use the peeking approach until libxproc.a works for other
  41    processes.  */
  42
  43 #include "defs.h"
  44
  45 #include <sys/types.h>
  46 #include <signal.h>
  47 #include "gdb_string.h"
  48
  49 #include "bfd.h"
  50 #include "symtab.h"
  51 #include "symfile.h"
  52 #include "objfiles.h"
  53 #include "target.h"
  54 #include "inferior.h"
  55 #include "gdbthread.h"
  56 #include "solist.h"
  57 #include "solib.h"
  58
  59 #ifdef USE_LDR_ROUTINES
  60 # include <loader.h>
  61 #endif
  62
  63 #ifndef USE_LDR_ROUTINES
  64 /* Definition of runtime loader structures, found by experimentation.  */
  65 #define RLD_CONTEXT_ADDRESS     0x3ffc0000000
  66
  67 /* Per-module information structure referenced by ldr_context_t.head.  */
  68
  69 typedef struct
  70   {
  71     CORE_ADDR next;
  72     CORE_ADDR previous;
  73     CORE_ADDR unknown1;
  74     CORE_ADDR module_name;
  75     CORE_ADDR modinfo_addr;     /* Used by next_link_map_member() to detect
  76                                    the end of the shared module list.  */
  77     long module_id;
  78     CORE_ADDR unknown2;
  79     CORE_ADDR unknown3;
  80     long region_count;
  81     CORE_ADDR regioninfo_addr;
  82   }
  83 ldr_module_info_t;
  84
  85 /* Per-region structure referenced by ldr_module_info_t.regioninfo_addr.  */
  86
  87 typedef struct
  88   {
  89     long unknown1;
  90     CORE_ADDR regionname_addr;
  91     long protection;
  92     CORE_ADDR vaddr;
  93     CORE_ADDR mapaddr;
  94     long size;
  95     long unknown2[5];
  96   }
  97 ldr_region_info_t;
  98
  99 /* Structure at RLD_CONTEXT_ADDRESS specifying the start and finish addresses
 100    of the shared module list.  */
 101
 102 typedef struct
 103   {
 104     CORE_ADDR unknown1;
 105     CORE_ADDR unknown2;
 106     CORE_ADDR head;
 107     CORE_ADDR tail;
 108   }
 109 ldr_context_t;
 110 #endif   /* !USE_LDR_ROUTINES */
 111
 112 /* Per-section information, stored in struct lm_info.secs.  */
 113
 114 struct lm_sec
 115   {
 116     CORE_ADDR offset;           /* difference between default and actual
 117                                    virtual addresses of section .name */
 118     CORE_ADDR nameaddr;         /* address in inferior of section name */
 119     const char *name;           /* name of section, null if not fetched */
 120   };
 121
 122 /* Per-module information, stored in struct so_list.lm_info.  */
 123
 124 struct lm_info
 125   {
 126     int isloader;               /* whether the module is /sbin/loader */
 127     int nsecs;                  /* length of .secs */
 128     struct lm_sec secs[1];      /* variable-length array of sections, sorted
 129                                    by name */
 130   };
 131
 132 /* Context for iterating through the inferior's shared module list.  */
 133
 134 struct read_map_ctxt
 135   {
 136 #ifdef USE_LDR_ROUTINES
 137     ldr_process_t proc;
 138     ldr_module_t next;
 139 #else
 140     CORE_ADDR next;             /* next element in module list */
 141     CORE_ADDR tail;             /* last element in module list */
 142 #endif
 143   };
 144
 145 /* Forward declaration for this module's autoinit function.  */
 146
 147 extern void _initialize_osf_solib (void);
 148
 149 #ifdef USE_LDR_ROUTINES
 150 # if 0
 151 /* This routine is intended to be called by ldr_* routines to read memory from
 152    the current target.  Usage:
 153
 154      ldr_process = ldr_core_process ();
 155      ldr_set_core_reader (ldr_read_memory);
 156      ldr_xdetach (ldr_process);
 157      ldr_xattach (ldr_process);
 158
 159    ldr_core_process() and ldr_read_memory() are neither documented nor
 160    declared in system header files.  They work with OSF/1 2.x, and they might
 161    work with later versions as well.  */
 162
 163 static int
 164 ldr_read_memory (CORE_ADDR memaddr, char *myaddr, int len, int readstring)
 165 {
 166   int result;
 167   char *buffer;
 168
 169   if (readstring)
 170     {
 171       target_read_string (memaddr, &buffer, len, &result);
 172       if (result == 0)
 173         strcpy (myaddr, buffer);
 174       xfree (buffer);
 175     }
 176   else
 177     result = target_read_memory (memaddr, myaddr, len);
 178
 179   if (result != 0)
 180     result = -result;
 181   return result;
 182 }
 183 # endif   /* 0 */
 184 #endif   /* USE_LDR_ROUTINES */
 185
 186 /* Comparison for qsort() and bsearch(): return -1, 0, or 1 according to
 187    whether lm_sec *P1's name is lexically less than, equal to, or greater
 188    than that of *P2.  */
 189
 190 static int
 191 lm_sec_cmp (const void *p1, const void *p2)
 192 {
 193   const struct lm_sec *lms1 = p1, *lms2 = p2;
 194
 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
 201 static void
 202 lm_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
 209 static void
 210 fetch_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"),
 224                    lms->nameaddr);
 225           name = xstrdup ("");
 226         }
 227       lms->name = name;
 228     }
 229   lm_secs_sort (lmi);
 230 #endif
 231 }
 232
 233 /* target_so_ops callback.  Adjust SEC's addresses after it's been mapped into
 234    the process.  */
 235
 236 static void
 237 osf_relocate_section_addresses (struct so_list *so,
 238                                 struct target_section *sec)
 239 {
 240   struct lm_info *lmi;
 241   struct lm_sec lms_key, *lms;
 242
 243   /* Fetch SO's section names if we haven't done so already.  */
 244   lmi = so->lm_info;
 245   if (lmi->nsecs && !lmi->secs[0].name)
 246     fetch_sec_names (lmi);
 247
 248   /* Binary-search for offset information corresponding to SEC.  */
 249   lms_key.name = sec->the_bfd_section->name;
 250   lms = bsearch (&lms_key, lmi->secs, lmi->nsecs, sizeof *lms, lm_sec_cmp);
 251   if (lms)
 252     {
 253       sec->addr += lms->offset;
 254       sec->endaddr += lms->offset;
 255     }
 256 }
 257
 258 /* target_so_ops callback.  Free parts of SO allocated by this file.  */
 259
 260 static void
 261 osf_free_so (struct so_list *so)
 262 {
 263   int i;
 264   const char *name;
 265
 266   for (i = 0; i < so->lm_info->nsecs; i++)
 267     {
 268       name = so->lm_info->secs[i].name;
 269       if (name)
 270         xfree ((void *) name);
 271     }
 272   xfree (so->lm_info);
 273 }
 274
 275 /* target_so_ops callback.  Discard information accumulated by this file and
 276    not freed by osf_free_so().  */
 277
 278 static void
 279 osf_clear_solib (void)
 280 {
 281   return;
 282 }
 283
 284 /* target_so_ops callback.  Prepare to handle shared libraries after the
 285    inferior process has been created but before it's executed any
 286    instructions.
 287
 288    For a statically bound executable, the inferior's first instruction is the
 289    one at "_start", or a similar text label.  No further processing is needed
 290    in that case.
 291
 292    For a dynamically bound executable, this first instruction is somewhere
 293    in the rld, and the actual user executable is not yet mapped in.
 294    We continue the inferior again, rld then maps in the actual user
 295    executable and any needed shared libraries and then sends
 296    itself a SIGTRAP.
 297
 298    At that point we discover the names of all shared libraries and
 299    read their symbols in.
 300
 301    FIXME
 302
 303    This code does not properly handle hitting breakpoints which the
 304    user might have set in the rld itself.  Proper handling would have
 305    to check if the SIGTRAP happened due to a kill call.
 306
 307    Also, what if child has exit()ed?  Must exit loop somehow.  */
 308
 309 static void
 310 osf_solib_create_inferior_hook (int from_tty)
 311 {
 312   struct inferior *inf;
 313   struct thread_info *tp;
 314
 315   inf = current_inferior ();
 316
 317   /* If we are attaching to the inferior, the shared libraries
 318      have already been mapped, so nothing more to do.  */
 319   if (inf->attach_flag)
 320     return;
 321
 322   /* Nothing to do for statically bound executables.  */
 323
 324   if (symfile_objfile == NULL
 325       || symfile_objfile->obfd == NULL
 326       || ((bfd_get_file_flags (symfile_objfile->obfd) & DYNAMIC) == 0))
 327     return;
 328
 329   /* Now run the target.  It will eventually get a SIGTRAP, at
 330      which point all of the libraries will have been mapped in and we
 331      can go groveling around in the rld structures to find
 332      out what we need to know about them.
 333
 334      If debugging from a core file, we cannot resume the execution
 335      of the inferior.  But this is actually not an issue, because
 336      shared libraries have already been mapped anyways, which means
 337      we have nothing more to do.  */
 338   if (!target_can_run (&current_target))
 339     return;
 340
 341   tp = inferior_thread ();
 342   clear_proceed_status ();
 343   inf->control.stop_soon = STOP_QUIETLY;
 344   tp->suspend.stop_signal = GDB_SIGNAL_0;
 345   do
 346     {
 347       target_resume (minus_one_ptid, 0, tp->suspend.stop_signal);
 348       wait_for_inferior ();
 349     }
 350   while (tp->suspend.stop_signal != GDB_SIGNAL_TRAP);
 351
 352   /*  solib_add will call reinit_frame_cache.
 353      But we are stopped in the runtime loader and we do not have symbols
 354      for the runtime loader.  So heuristic_proc_start will be called
 355      and will put out an annoying warning.
 356      Delaying the resetting of stop_soon until after symbol loading
 357      suppresses the warning.  */
 358   solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
 359   inf->control.stop_soon = NO_STOP_QUIETLY;
 360 }
 361
 362 /* target_so_ops callback.  Do additional symbol handling, lookup, etc. after
 363    symbols for a shared object have been loaded.  */
 364
 365 static void
 366 osf_special_symbol_handling (void)
 367 {
 368   return;
 369 }
 370
 371 /* Initialize CTXT in preparation for iterating through the inferior's module
 372    list using read_map().  Return success.  */
 373
 374 static int
 375 open_map (struct read_map_ctxt *ctxt)
 376 {
 377 #ifdef USE_LDR_ROUTINES
 378   /* Note: As originally written, ldr_my_process() was used to obtain
 379      the value for ctxt->proc.  This is incorrect, however, since
 380      ldr_my_process() retrieves the "unique identifier" associated
 381      with the current process (i.e. GDB) and not the one being
 382      debugged.  Presumably, the pid of the process being debugged is
 383      compatible with the "unique identifier" used by the ldr_
 384      routines, so we use that.  */
 385   ctxt->proc = ptid_get_pid (inferior_ptid);
 386   if (ldr_xattach (ctxt->proc) != 0)
 387     return 0;
 388   ctxt->next = LDR_NULL_MODULE;
 389 #else
 390   CORE_ADDR ldr_context_addr, prev, next;
 391   ldr_context_t ldr_context;
 392
 393   if (target_read_memory ((CORE_ADDR) RLD_CONTEXT_ADDRESS,
 394                           (char *) &ldr_context_addr,
 395                           sizeof (CORE_ADDR)) != 0)
 396     return 0;
 397   if (target_read_memory (ldr_context_addr,
 398                           (char *) &ldr_context,
 399                           sizeof (ldr_context_t)) != 0)
 400     return 0;
 401   ctxt->next = ldr_context.head;
 402   ctxt->tail = ldr_context.tail;
 403 #endif
 404   return 1;
 405 }
 406
 407 /* Initialize SO to have module NAME, /sbin/loader indicator ISLOADR, and
 408    space for NSECS sections.  */
 409
 410 static void
 411 init_so (struct so_list *so, char *name, int isloader, int nsecs)
 412 {
 413   int namelen, i;
 414
 415   /* solib.c requires various fields to be initialized to 0.  */
 416   memset (so, 0, sizeof *so);
 417
 418   /* Copy the name.  */
 419   namelen = strlen (name);
 420   if (namelen >= SO_NAME_MAX_PATH_SIZE)
 421     namelen = SO_NAME_MAX_PATH_SIZE - 1;
 422
 423   memcpy (so->so_original_name, name, namelen);
 424   so->so_original_name[namelen] = '\0';
 425   memcpy (so->so_name, so->so_original_name, namelen + 1);
 426
 427   /* Allocate section space.  */
 428   so->lm_info = xmalloc (sizeof (struct lm_info)
 429                          + (nsecs - 1) * sizeof (struct lm_sec));
 430   so->lm_info->isloader = isloader;
 431   so->lm_info->nsecs = nsecs;
 432   for (i = 0; i < nsecs; i++)
 433     so->lm_info->secs[i].name = NULL;
 434 }
 435
 436 /* Initialize SO's section SECIDX with name address NAMEADDR, name string
 437    NAME, default virtual address VADDR, and actual virtual address
 438    MAPADDR.  */
 439
 440 static void
 441 init_sec (struct so_list *so, int secidx, CORE_ADDR nameaddr,
 442           const char *name, CORE_ADDR vaddr, CORE_ADDR mapaddr)
 443 {
 444   struct lm_sec *lms;
 445
 446   lms = so->lm_info->secs + secidx;
 447   lms->nameaddr = nameaddr;
 448   lms->name = name;
 449   lms->offset = mapaddr - vaddr;
 450 }
 451
 452 /* If there are more elements starting at CTXT in inferior's module list,
 453    store the next element in SO, advance CTXT to the next element, and return
 454    1, else return 0.  */
 455
 456 static int
 457 read_map (struct read_map_ctxt *ctxt, struct so_list *so)
 458 {
 459   ldr_module_info_t minf;
 460   ldr_region_info_t rinf;
 461
 462 #ifdef USE_LDR_ROUTINES
 463   size_t size;
 464   ldr_region_t i;
 465
 466   /* Retrieve the next element.  */
 467   if (ldr_next_module (ctxt->proc, &ctxt->next) != 0)
 468     return 0;
 469   if (ctxt->next == LDR_NULL_MODULE)
 470     return 0;
 471   if (ldr_inq_module (ctxt->proc, ctxt->next, &minf, sizeof minf, &size) != 0)
 472     return 0;
 473
 474   /* Initialize the module name and section count.  */
 475   init_so (so, minf.lmi_name, 0, minf.lmi_nregion);
 476
 477   /* Retrieve section names and offsets.  */
 478   for (i = 0; i < minf.lmi_nregion; i++)
 479     {
 480       if (ldr_inq_region (ctxt->proc, ctxt->next, i, &rinf,
 481                           sizeof rinf, &size) != 0)
 482         goto err;
 483       init_sec (so, (int) i, 0, xstrdup (rinf.lri_name),
 484                 (CORE_ADDR) rinf.lri_vaddr, (CORE_ADDR) rinf.lri_mapaddr);
 485     }
 486   lm_secs_sort (so->lm_info);
 487 #else
 488   char *name;
 489   int errcode, i;
 490
 491   /* Retrieve the next element.  */
 492   if (!ctxt->next)
 493     return 0;
 494   if (target_read_memory (ctxt->next, (char *) &minf, sizeof minf) != 0)
 495     return 0;
 496   if (ctxt->next == ctxt->tail)
 497     ctxt->next = 0;
 498   else
 499     ctxt->next = minf.next;
 500
 501   /* Initialize the module name and section count.  */
 502   target_read_string (minf.module_name, &name, PATH_MAX, &errcode);
 503   if (errcode != 0)
 504     return 0;
 505   init_so (so, name, !minf.modinfo_addr, minf.region_count);
 506   xfree (name);
 507
 508   /* Retrieve section names and offsets.  */
 509   for (i = 0; i < minf.region_count; i++)
 510     {
 511       if (target_read_memory (minf.regioninfo_addr + i * sizeof rinf,
 512                               (char *) &rinf, sizeof rinf) != 0)
 513         goto err;
 514       init_sec (so, i, rinf.regionname_addr, NULL, rinf.vaddr, rinf.mapaddr);
 515     }
 516 #endif   /* !USE_LDR_ROUTINES */
 517   return 1;
 518
 519  err:
 520   osf_free_so (so);
 521   return 0;
 522 }
 523
 524 /* Free resources allocated by open_map (CTXT).  */
 525
 526 static void
 527 close_map (struct read_map_ctxt *ctxt)
 528 {
 529 #ifdef USE_LDR_ROUTINES
 530   ldr_xdetach (ctxt->proc);
 531 #endif
 532 }
 533
 534 /* target_so_ops callback.  Return a list of shared objects currently loaded
 535    in the inferior.  */
 536
 537 static struct so_list *
 538 osf_current_sos (void)
 539 {
 540   struct so_list *head = NULL, *tail = NULL, *newtail, so;
 541   struct read_map_ctxt ctxt;
 542   int skipped_main;
 543
 544   if (!open_map (&ctxt))
 545     return NULL;
 546
 547   /* Read subsequent elements.  */
 548   for (skipped_main = 0;;)
 549     {
 550       if (!read_map (&ctxt, &so))
 551         break;
 552
 553       /* Skip the main program module, which is first in the list after
 554          /sbin/loader.  */
 555       if (!so.lm_info->isloader && !skipped_main)
 556         {
 557           osf_free_so (&so);
 558           skipped_main = 1;
 559           continue;
 560         }
 561
 562       newtail = xmalloc (sizeof *newtail);
 563       if (!head)
 564         head = newtail;
 565       else
 566         tail->next = newtail;
 567       tail = newtail;
 568
 569       memcpy (tail, &so, sizeof so);
 570       tail->next = NULL;
 571     }
 572
 573   close_map (&ctxt);
 574   return head;
 575 }
 576
 577 /* target_so_ops callback.  Attempt to locate and open the main symbol
 578    file.  */
 579
 580 static int
 581 osf_open_symbol_file_object (void *from_ttyp)
 582 {
 583   struct read_map_ctxt ctxt;
 584   struct so_list so;
 585   int found;
 586
 587   if (symfile_objfile)
 588     if (!query (_("Attempt to reload symbols from process? ")))
 589       return 0;
 590
 591   /* The first module after /sbin/loader is the main program.  */
 592   if (!open_map (&ctxt))
 593     return 0;
 594   for (found = 0; !found;)
 595     {
 596       if (!read_map (&ctxt, &so))
 597         break;
 598       found = !so.lm_info->isloader;
 599       osf_free_so (&so);
 600     }
 601   close_map (&ctxt);
 602
 603   if (found)
 604     symbol_file_add_main (so.so_name, *(int *) from_ttyp);
 605   return found;
 606 }
 607
 608 /* target_so_ops callback.  Return whether PC is in the dynamic linker.  */
 609
 610 static int
 611 osf_in_dynsym_resolve_code (CORE_ADDR pc)
 612 {
 613   /* This function currently always return False.  This is a temporary
 614      solution which only consequence is to introduce a minor incovenience
 615      for the user: When stepping inside a subprogram located in a shared
 616      library, gdb might stop inside the dynamic loader code instead of
 617      inside the subprogram itself.  See the explanations in infrun.c about
 618      the in_solib_dynsym_resolve_code() function for more details.  */
 619   return 0;
 620 }
 621
 622 static struct target_so_ops osf_so_ops;
 623
 624 void
 625 _initialize_osf_solib (void)
 626 {
 627   osf_so_ops.relocate_section_addresses = osf_relocate_section_addresses;
 628   osf_so_ops.free_so = osf_free_so;
 629   osf_so_ops.clear_solib = osf_clear_solib;
 630   osf_so_ops.solib_create_inferior_hook = osf_solib_create_inferior_hook;
 631   osf_so_ops.special_symbol_handling = osf_special_symbol_handling;
 632   osf_so_ops.current_sos = osf_current_sos;
 633   osf_so_ops.open_symbol_file_object = osf_open_symbol_file_object;
 634   osf_so_ops.in_dynsym_resolve_code = osf_in_dynsym_resolve_code;
 635   osf_so_ops.bfd_open = solib_bfd_open;
 636
 637   /* FIXME: Don't do this here.  *_gdbarch_init() should set so_ops.  */
 638   current_target_so_ops = &osf_so_ops;
 639 }