gdb/solib-osf.c

   1 /* Handle OSF/1, Digital UNIX, and Tru64 shared libraries
   2    for GDB, the GNU Debugger.
   3    Copyright (C) 1993-2014 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 <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 "infrun.h"
  56 #include "gdbthread.h"
  57 #include "solist.h"
  58 #include "solib.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
  70 typedef 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   }
  84 ldr_module_info_t;
  85
  86 /* Per-region structure referenced by ldr_module_info_t.regioninfo_addr.  */
  87
  88 typedef 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   }
  98 ldr_region_info_t;
  99
 100 /* Structure at RLD_CONTEXT_ADDRESS specifying the start and finish addresses
 101    of the shared module list.  */
 102
 103 typedef struct
 104   {
 105     CORE_ADDR unknown1;
 106     CORE_ADDR unknown2;
 107     CORE_ADDR head;
 108     CORE_ADDR tail;
 109   }
 110 ldr_context_t;
 111 #endif   /* !USE_LDR_ROUTINES */
 112
 113 /* Per-section information, stored in struct lm_info.secs.  */
 114
 115 struct 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
 125 struct 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
 135 struct 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
 148 extern 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
 164 static int
 165 ldr_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
 191 static int
 192 lm_sec_cmp (const void *p1, const void *p2)
 193 {
 194   const struct lm_sec *lms1 = p1, *lms2 = p2;
 195
 196   return strcmp (lms1->name, lms2->name);
 197 }
 198
 199 /* Sort LMI->secs so that osf_relocate_section_addresses() can binary-search
 200    it.  */
 201
 202 static void
 203 lm_secs_sort (struct lm_info *lmi)
 204 {
 205   qsort (lmi->secs, lmi->nsecs, sizeof *lmi->secs, lm_sec_cmp);
 206 }
 207
 208 /* Populate name fields of LMI->secs.  */
 209
 210 static void
 211 fetch_sec_names (struct lm_info *lmi)
 212 {
 213 #ifndef USE_LDR_ROUTINES
 214   int i, errcode;
 215   struct lm_sec *lms;
 216   char *name;
 217
 218   for (i = 0; i < lmi->nsecs; i++)
 219     {
 220       lms = lmi->secs + i;
 221       target_read_string (lms->nameaddr, &name, PATH_MAX, &errcode);
 222       if (errcode != 0)
 223         {
 224           warning (_("unable to read shared sec name at 0x%lx"),
 225                    lms->nameaddr);
 226           name = xstrdup ("");
 227         }
 228       lms->name = name;
 229     }
 230   lm_secs_sort (lmi);
 231 #endif
 232 }
 233
 234 /* target_so_ops callback.  Adjust SEC's addresses after it's been mapped into
 235    the process.  */
 236
 237 static void
 238 osf_relocate_section_addresses (struct so_list *so,
 239                                 struct target_section *sec)
 240 {
 241   struct lm_info *lmi;
 242   struct lm_sec lms_key, *lms;
 243
 244   /* Fetch SO's section names if we haven't done so already.  */
 245   lmi = so->lm_info;
 246   if (lmi->nsecs && !lmi->secs[0].name)
 247     fetch_sec_names (lmi);
 248
 249   /* Binary-search for offset information corresponding to SEC.  */
 250   lms_key.name = sec->the_bfd_section->name;
 251   lms = bsearch (&lms_key, lmi->secs, lmi->nsecs, sizeof *lms, lm_sec_cmp);
 252   if (lms)
 253     {
 254       sec->addr += lms->offset;
 255       sec->endaddr += lms->offset;
 256     }
 257 }
 258
 259 /* target_so_ops callback.  Free parts of SO allocated by this file.  */
 260
 261 static void
 262 osf_free_so (struct so_list *so)
 263 {
 264   int i;
 265   const char *name;
 266
 267   for (i = 0; i < so->lm_info->nsecs; i++)
 268     {
 269       name = so->lm_info->secs[i].name;
 270       if (name)
 271         xfree ((void *) name);
 272     }
 273   xfree (so->lm_info);
 274 }
 275
 276 /* target_so_ops callback.  Discard information accumulated by this file and
 277    not freed by osf_free_so().  */
 278
 279 static void
 280 osf_clear_solib (void)
 281 {
 282   return;
 283 }
 284
 285 /* target_so_ops callback.  Prepare to handle shared libraries after the
 286    inferior process has been created but before it's executed any
 287    instructions.
 288
 289    For a statically bound executable, the inferior's first instruction is the
 290    one at "_start", or a similar text label.  No further processing is needed
 291    in that case.
 292
 293    For a dynamically bound executable, this first instruction is somewhere
 294    in the rld, and the actual user executable is not yet mapped in.
 295    We continue the inferior again, rld then maps in the actual user
 296    executable and any needed shared libraries and then sends
 297    itself a SIGTRAP.
 298
 299    At that point we discover the names of all shared libraries and
 300    read their symbols in.
 301
 302    FIXME
 303
 304    This code does not properly handle hitting breakpoints which the
 305    user might have set in the rld itself.  Proper handling would have
 306    to check if the SIGTRAP happened due to a kill call.
 307
 308    Also, what if child has exit()ed?  Must exit loop somehow.  */
 309
 310 static void
 311 osf_solib_create_inferior_hook (int from_tty)
 312 {
 313   struct inferior *inf;
 314   struct thread_info *tp;
 315
 316   inf = current_inferior ();
 317
 318   /* If we are attaching to the inferior, the shared libraries
 319      have already been mapped, so nothing more to do.  */
 320   if (inf->attach_flag)
 321     return;
 322
 323   /* Nothing to do for statically bound executables.  */
 324
 325   if (symfile_objfile == NULL
 326       || symfile_objfile->obfd == NULL
 327       || ((bfd_get_file_flags (symfile_objfile->obfd) & DYNAMIC) == 0))
 328     return;
 329
 330   /* Now run the target.  It will eventually get a SIGTRAP, at
 331      which point all of the libraries will have been mapped in and we
 332      can go groveling around in the rld structures to find
 333      out what we need to know about them.
 334
 335      If debugging from a core file, we cannot resume the execution
 336      of the inferior.  But this is actually not an issue, because
 337      shared libraries have already been mapped anyways, which means
 338      we have nothing more to do.  */
 339   if (!target_can_run (&current_target))
 340     return;
 341
 342   tp = inferior_thread ();
 343   clear_proceed_status ();
 344   inf->control.stop_soon = STOP_QUIETLY;
 345   tp->suspend.stop_signal = GDB_SIGNAL_0;
 346   do
 347     {
 348       target_resume (minus_one_ptid, 0, tp->suspend.stop_signal);
 349       wait_for_inferior ();
 350     }
 351   while (tp->suspend.stop_signal != GDB_SIGNAL_TRAP);
 352
 353   /*  solib_add will call reinit_frame_cache.
 354      But we are stopped in the runtime loader and we do not have symbols
 355      for the runtime loader.  So heuristic_proc_start will be called
 356      and will put out an annoying warning.
 357      Delaying the resetting of stop_soon until after symbol loading
 358      suppresses the warning.  */
 359   solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
 360   inf->control.stop_soon = NO_STOP_QUIETLY;
 361 }
 362
 363 /* target_so_ops callback.  Do additional symbol handling, lookup, etc. after
 364    symbols for a shared object have been loaded.  */
 365
 366 static void
 367 osf_special_symbol_handling (void)
 368 {
 369   return;
 370 }
 371
 372 /* Initialize CTXT in preparation for iterating through the inferior's module
 373    list using read_map().  Return success.  */
 374
 375 static int
 376 open_map (struct read_map_ctxt *ctxt)
 377 {
 378 #ifdef USE_LDR_ROUTINES
 379   /* Note: As originally written, ldr_my_process() was used to obtain
 380      the value for ctxt->proc.  This is incorrect, however, since
 381      ldr_my_process() retrieves the "unique identifier" associated
 382      with the current process (i.e. GDB) and not the one being
 383      debugged.  Presumably, the pid of the process being debugged is
 384      compatible with the "unique identifier" used by the ldr_
 385      routines, so we use that.  */
 386   ctxt->proc = ptid_get_pid (inferior_ptid);
 387   if (ldr_xattach (ctxt->proc) != 0)
 388     return 0;
 389   ctxt->next = LDR_NULL_MODULE;
 390 #else
 391   CORE_ADDR ldr_context_addr, prev, next;
 392   ldr_context_t ldr_context;
 393
 394   if (target_read_memory ((CORE_ADDR) RLD_CONTEXT_ADDRESS,
 395                           (char *) &ldr_context_addr,
 396                           sizeof (CORE_ADDR)) != 0)
 397     return 0;
 398   if (target_read_memory (ldr_context_addr,
 399                           (char *) &ldr_context,
 400                           sizeof (ldr_context_t)) != 0)
 401     return 0;
 402   ctxt->next = ldr_context.head;
 403   ctxt->tail = ldr_context.tail;
 404 #endif
 405   return 1;
 406 }
 407
 408 /* Initialize SO to have module NAME, /sbin/loader indicator ISLOADR, and
 409    space for NSECS sections.  */
 410
 411 static void
 412 init_so (struct so_list *so, char *name, int isloader, int nsecs)
 413 {
 414   int namelen, i;
 415
 416   /* solib.c requires various fields to be initialized to 0.  */
 417   memset (so, 0, sizeof *so);
 418
 419   /* Copy the name.  */
 420   namelen = strlen (name);
 421   if (namelen >= SO_NAME_MAX_PATH_SIZE)
 422     namelen = SO_NAME_MAX_PATH_SIZE - 1;
 423
 424   memcpy (so->so_original_name, name, namelen);
 425   so->so_original_name[namelen] = '\0';
 426   memcpy (so->so_name, so->so_original_name, namelen + 1);
 427
 428   /* Allocate section space.  */
 429   so->lm_info = xmalloc (sizeof (struct lm_info)
 430                          + (nsecs - 1) * sizeof (struct lm_sec));
 431   so->lm_info->isloader = isloader;
 432   so->lm_info->nsecs = nsecs;
 433   for (i = 0; i < nsecs; i++)
 434     so->lm_info->secs[i].name = NULL;
 435 }
 436
 437 /* Initialize SO's section SECIDX with name address NAMEADDR, name string
 438    NAME, default virtual address VADDR, and actual virtual address
 439    MAPADDR.  */
 440
 441 static void
 442 init_sec (struct so_list *so, int secidx, CORE_ADDR nameaddr,
 443           const char *name, CORE_ADDR vaddr, CORE_ADDR mapaddr)
 444 {
 445   struct lm_sec *lms;
 446
 447   lms = so->lm_info->secs + secidx;
 448   lms->nameaddr = nameaddr;
 449   lms->name = name;
 450   lms->offset = mapaddr - vaddr;
 451 }
 452
 453 /* If there are more elements starting at CTXT in inferior's module list,
 454    store the next element in SO, advance CTXT to the next element, and return
 455    1, else return 0.  */
 456
 457 static int
 458 read_map (struct read_map_ctxt *ctxt, struct so_list *so)
 459 {
 460   ldr_module_info_t minf;
 461   ldr_region_info_t rinf;
 462
 463 #ifdef USE_LDR_ROUTINES
 464   size_t size;
 465   ldr_region_t i;
 466
 467   /* Retrieve the next element.  */
 468   if (ldr_next_module (ctxt->proc, &ctxt->next) != 0)
 469     return 0;
 470   if (ctxt->next == LDR_NULL_MODULE)
 471     return 0;
 472   if (ldr_inq_module (ctxt->proc, ctxt->next, &minf, sizeof minf, &size) != 0)
 473     return 0;
 474
 475   /* Initialize the module name and section count.  */
 476   init_so (so, minf.lmi_name, 0, minf.lmi_nregion);
 477
 478   /* Retrieve section names and offsets.  */
 479   for (i = 0; i < minf.lmi_nregion; i++)
 480     {
 481       if (ldr_inq_region (ctxt->proc, ctxt->next, i, &rinf,
 482                           sizeof rinf, &size) != 0)
 483         goto err;
 484       init_sec (so, (int) i, 0, xstrdup (rinf.lri_name),
 485                 (CORE_ADDR) rinf.lri_vaddr, (CORE_ADDR) rinf.lri_mapaddr);
 486     }
 487   lm_secs_sort (so->lm_info);
 488 #else
 489   char *name;
 490   int errcode, i;
 491
 492   /* Retrieve the next element.  */
 493   if (!ctxt->next)
 494     return 0;
 495   if (target_read_memory (ctxt->next, (char *) &minf, sizeof minf) != 0)
 496     return 0;
 497   if (ctxt->next == ctxt->tail)
 498     ctxt->next = 0;
 499   else
 500     ctxt->next = minf.next;
 501
 502   /* Initialize the module name and section count.  */
 503   target_read_string (minf.module_name, &name, PATH_MAX, &errcode);
 504   if (errcode != 0)
 505     return 0;
 506   init_so (so, name, !minf.modinfo_addr, minf.region_count);
 507   xfree (name);
 508
 509   /* Retrieve section names and offsets.  */
 510   for (i = 0; i < minf.region_count; i++)
 511     {
 512       if (target_read_memory (minf.regioninfo_addr + i * sizeof rinf,
 513                               (char *) &rinf, sizeof rinf) != 0)
 514         goto err;
 515       init_sec (so, i, rinf.regionname_addr, NULL, rinf.vaddr, rinf.mapaddr);
 516     }
 517 #endif   /* !USE_LDR_ROUTINES */
 518   return 1;
 519
 520  err:
 521   osf_free_so (so);
 522   return 0;
 523 }
 524
 525 /* Free resources allocated by open_map (CTXT).  */
 526
 527 static void
 528 close_map (struct read_map_ctxt *ctxt)
 529 {
 530 #ifdef USE_LDR_ROUTINES
 531   ldr_xdetach (ctxt->proc);
 532 #endif
 533 }
 534
 535 /* target_so_ops callback.  Return a list of shared objects currently loaded
 536    in the inferior.  */
 537
 538 static struct so_list *
 539 osf_current_sos (void)
 540 {
 541   struct so_list *head = NULL, *tail = NULL, *newtail, so;
 542   struct read_map_ctxt ctxt;
 543   int skipped_main;
 544
 545   if (!open_map (&ctxt))
 546     return NULL;
 547
 548   /* Read subsequent elements.  */
 549   for (skipped_main = 0;;)
 550     {
 551       if (!read_map (&ctxt, &so))
 552         break;
 553
 554       /* Skip the main program module, which is first in the list after
 555          /sbin/loader.  */
 556       if (!so.lm_info->isloader && !skipped_main)
 557         {
 558           osf_free_so (&so);
 559           skipped_main = 1;
 560           continue;
 561         }
 562
 563       newtail = xmalloc (sizeof *newtail);
 564       if (!head)
 565         head = newtail;
 566       else
 567         tail->next = newtail;
 568       tail = newtail;
 569
 570       memcpy (tail, &so, sizeof so);
 571       tail->next = NULL;
 572     }
 573
 574   close_map (&ctxt);
 575   return head;
 576 }
 577
 578 /* target_so_ops callback.  Attempt to locate and open the main symbol
 579    file.  */
 580
 581 static int
 582 osf_open_symbol_file_object (void *from_ttyp)
 583 {
 584   struct read_map_ctxt ctxt;
 585   struct so_list so;
 586   int found;
 587
 588   if (symfile_objfile)
 589     if (!query (_("Attempt to reload symbols from process? ")))
 590       return 0;
 591
 592   /* The first module after /sbin/loader is the main program.  */
 593   if (!open_map (&ctxt))
 594     return 0;
 595   for (found = 0; !found;)
 596     {
 597       if (!read_map (&ctxt, &so))
 598         break;
 599       found = !so.lm_info->isloader;
 600       osf_free_so (&so);
 601     }
 602   close_map (&ctxt);
 603
 604   if (found)
 605     symbol_file_add_main (so.so_name, *(int *) from_ttyp);
 606   return found;
 607 }
 608
 609 /* target_so_ops callback.  Return whether PC is in the dynamic linker.  */
 610
 611 static int
 612 osf_in_dynsym_resolve_code (CORE_ADDR pc)
 613 {
 614   /* This function currently always return False.  This is a temporary
 615      solution which only consequence is to introduce a minor incovenience
 616      for the user: When stepping inside a subprogram located in a shared
 617      library, gdb might stop inside the dynamic loader code instead of
 618      inside the subprogram itself.  See the explanations in infrun.c about
 619      the in_solib_dynsym_resolve_code() function for more details.  */
 620   return 0;
 621 }
 622
 623 static struct target_so_ops osf_so_ops;
 624
 625 void
 626 _initialize_osf_solib (void)
 627 {
 628   osf_so_ops.relocate_section_addresses = osf_relocate_section_addresses;
 629   osf_so_ops.free_so = osf_free_so;
 630   osf_so_ops.clear_solib = osf_clear_solib;
 631   osf_so_ops.solib_create_inferior_hook = osf_solib_create_inferior_hook;
 632   osf_so_ops.special_symbol_handling = osf_special_symbol_handling;
 633   osf_so_ops.current_sos = osf_current_sos;
 634   osf_so_ops.open_symbol_file_object = osf_open_symbol_file_object;
 635   osf_so_ops.in_dynsym_resolve_code = osf_in_dynsym_resolve_code;
 636   osf_so_ops.bfd_open = solib_bfd_open;
 637
 638   /* FIXME: Don't do this here.  *_gdbarch_init() should set so_ops.  */
 639   current_target_so_ops = &osf_so_ops;
 640 }