gdb/solib-osf.c

   1 /* Handle OSF/1, Digital UNIX, and Tru64 shared libraries
   2    for GDB, the GNU Debugger.
   3    Copyright (C) 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2007, 2008
   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 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 /* When handling shared libraries, GDB has to find out the pathnames
  22    of all shared libraries that are currently loaded (to read in their
  23    symbols) and where the shared libraries are loaded in memory
  24    (to relocate them properly from their prelinked addresses to the
  25    current load address).
  26
  27    Under OSF/1 there are two possibilities to get at this information:
  28
  29    1) Peek around in the runtime loader structures.
  30    These are not documented, and they are not defined in the system
  31    header files. The definitions below were obtained by experimentation,
  32    but they seem stable enough.
  33
  34    2) Use the libxproc.a library, which contains the equivalent ldr_*
  35    routines.  The library is documented in Tru64 5.x, but as of 5.1, it
  36    only allows a process to examine itself.  On earlier versions, it
  37    may require that the GDB executable be dynamically linked and that
  38    NAT_CLIBS include -lxproc -Wl,-expect_unresolved,ldr_process_context
  39    for GDB and all applications that are using libgdb.
  40
  41    We will use the peeking approach until libxproc.a works for other
  42    processes.  */
  43
  44 #include "defs.h"
  45
  46 #include <sys/types.h>
  47 #include <signal.h>
  48 #include "gdb_string.h"
  49
  50 #include "bfd.h"
  51 #include "symtab.h"
  52 #include "symfile.h"
  53 #include "objfiles.h"
  54 #include "target.h"
  55 #include "inferior.h"
  56 #include "solist.h"
  57
  58 #ifdef USE_LDR_ROUTINES
  59 # include <loader.h>
  60 #endif
  61
  62 #ifndef USE_LDR_ROUTINES
  63 /* Definition of runtime loader structures, found by experimentation.  */
  64 #define RLD_CONTEXT_ADDRESS     0x3ffc0000000
  65
  66 /* Per-module information structure referenced by ldr_context_t.head.  */
  67
  68 typedef struct
  69   {
  70     CORE_ADDR next;
  71     CORE_ADDR previous;
  72     CORE_ADDR unknown1;
  73     CORE_ADDR module_name;
  74     CORE_ADDR modinfo_addr;     /* used by next_link_map_member() to detect
  75                                    the end of the shared module list */
  76     long module_id;
  77     CORE_ADDR unknown2;
  78     CORE_ADDR unknown3;
  79     long region_count;
  80     CORE_ADDR regioninfo_addr;
  81   }
  82 ldr_module_info_t;
  83
  84 /* Per-region structure referenced by ldr_module_info_t.regioninfo_addr.  */
  85
  86 typedef struct
  87   {
  88     long unknown1;
  89     CORE_ADDR regionname_addr;
  90     long protection;
  91     CORE_ADDR vaddr;
  92     CORE_ADDR mapaddr;
  93     long size;
  94     long unknown2[5];
  95   }
  96 ldr_region_info_t;
  97
  98 /* Structure at RLD_CONTEXT_ADDRESS specifying the start and finish addresses
  99    of the shared module list.  */
 100
 101 typedef struct
 102   {
 103     CORE_ADDR unknown1;
 104     CORE_ADDR unknown2;
 105     CORE_ADDR head;
 106     CORE_ADDR tail;
 107   }
 108 ldr_context_t;
 109 #endif   /* !USE_LDR_ROUTINES */
 110
 111 /* Per-section information, stored in struct lm_info.secs.  */
 112
 113 struct lm_sec
 114   {
 115     CORE_ADDR offset;           /* difference between default and actual
 116                                    virtual addresses of section .name */
 117     CORE_ADDR nameaddr;         /* address in inferior of section name */
 118     const char *name;           /* name of section, null if not fetched */
 119   };
 120
 121 /* Per-module information, stored in struct so_list.lm_info.  */
 122
 123 struct lm_info
 124   {
 125     int isloader;               /* whether the module is /sbin/loader */
 126     int nsecs;                  /* length of .secs */
 127     struct lm_sec secs[1];      /* variable-length array of sections, sorted
 128                                    by name */
 129   };
 130
 131 /* Context for iterating through the inferior's shared module list.  */
 132
 133 struct read_map_ctxt
 134   {
 135 #ifdef USE_LDR_ROUTINES
 136     ldr_process_t proc;
 137     ldr_module_t next;
 138 #else
 139     CORE_ADDR next;             /* next element in module list */
 140     CORE_ADDR tail;             /* last element in module list */
 141 #endif
 142   };
 143
 144 /* Forward declaration for this module's autoinit function.  */
 145
 146 extern void _initialize_osf_solib (void);
 147
 148 #ifdef USE_LDR_ROUTINES
 149 # if 0
 150 /* This routine is intended to be called by ldr_* routines to read memory from
 151    the current target.  Usage:
 152
 153      ldr_process = ldr_core_process ();
 154      ldr_set_core_reader (ldr_read_memory);
 155      ldr_xdetach (ldr_process);
 156      ldr_xattach (ldr_process);
 157
 158    ldr_core_process() and ldr_read_memory() are neither documented nor
 159    declared in system header files.  They work with OSF/1 2.x, and they might
 160    work with later versions as well.  */
 161
 162 static int
 163 ldr_read_memory (CORE_ADDR memaddr, char *myaddr, int len, int readstring)
 164 {
 165   int result;
 166   char *buffer;
 167
 168   if (readstring)
 169     {
 170       target_read_string (memaddr, &buffer, len, &result);
 171       if (result == 0)
 172         strcpy (myaddr, buffer);
 173       xfree (buffer);
 174     }
 175   else
 176     result = target_read_memory (memaddr, myaddr, len);
 177
 178   if (result != 0)
 179     result = -result;
 180   return result;
 181 }
 182 # endif   /* 0 */
 183 #endif   /* USE_LDR_ROUTINES */
 184
 185 /* Comparison for qsort() and bsearch(): return -1, 0, or 1 according to
 186    whether lm_sec *P1's name is lexically less than, equal to, or greater
 187    than that of *P2.  */
 188
 189 static int
 190 lm_sec_cmp (const void *p1, const void *p2)
 191 {
 192   const struct lm_sec *lms1 = p1, *lms2 = p2;
 193   return strcmp (lms1->name, lms2->name);
 194 }
 195
 196 /* Sort LMI->secs so that osf_relocate_section_addresses() can binary-search
 197    it.  */
 198
 199 static void
 200 lm_secs_sort (struct lm_info *lmi)
 201 {
 202   qsort (lmi->secs, lmi->nsecs, sizeof *lmi->secs, lm_sec_cmp);
 203 }
 204
 205 /* Populate name fields of LMI->secs.  */
 206
 207 static void
 208 fetch_sec_names (struct lm_info *lmi)
 209 {
 210 #ifndef USE_LDR_ROUTINES
 211   int i, errcode;
 212   struct lm_sec *lms;
 213   char *name;
 214
 215   for (i = 0; i < lmi->nsecs; i++)
 216     {
 217       lms = lmi->secs + i;
 218       target_read_string (lms->nameaddr, &name, PATH_MAX, &errcode);
 219       if (errcode != 0)
 220         {
 221           warning (_("unable to read shared sec name at 0x%lx"), lms->nameaddr);
 222           name = xstrdup ("");
 223         }
 224       lms->name = name;
 225     }
 226   lm_secs_sort (lmi);
 227 #endif
 228 }
 229
 230 /* target_so_ops callback.  Adjust SEC's addresses after it's been mapped into
 231    the process.  */
 232
 233 static void
 234 osf_relocate_section_addresses (struct so_list *so,
 235                                 struct section_table *sec)
 236 {
 237   struct lm_info *lmi;
 238   struct lm_sec lms_key, *lms;
 239
 240   /* Fetch SO's section names if we haven't done so already.  */
 241   lmi = so->lm_info;
 242   if (lmi->nsecs && !lmi->secs[0].name)
 243     fetch_sec_names (lmi);
 244
 245   /* Binary-search for offset information corresponding to SEC.  */
 246   lms_key.name = sec->the_bfd_section->name;
 247   lms = bsearch (&lms_key, lmi->secs, lmi->nsecs, sizeof *lms, lm_sec_cmp);
 248   if (lms)
 249     {
 250       sec->addr += lms->offset;
 251       sec->endaddr += lms->offset;
 252     }
 253 }
 254
 255 /* target_so_ops callback.  Free parts of SO allocated by this file.  */
 256
 257 static void
 258 osf_free_so (struct so_list *so)
 259 {
 260   int i;
 261   const char *name;
 262
 263   for (i = 0; i < so->lm_info->nsecs; i++)
 264     {
 265       name = so->lm_info->secs[i].name;
 266       if (name)
 267         xfree ((void *) name);
 268     }
 269   xfree (so->lm_info);
 270 }
 271
 272 /* target_so_ops callback.  Discard information accumulated by this file and
 273    not freed by osf_free_so().  */
 274
 275 static void
 276 osf_clear_solib (void)
 277 {
 278   return;
 279 }
 280
 281 /* target_so_ops callback.  Prepare to handle shared libraries after the
 282    inferior process has been created but before it's executed any
 283    instructions.
 284
 285    For a statically bound executable, the inferior's first instruction is the
 286    one at "_start", or a similar text label. No further processing is needed
 287    in that case.
 288
 289    For a dynamically bound executable, this first instruction is somewhere
 290    in the rld, and the actual user executable is not yet mapped in.
 291    We continue the inferior again, rld then maps in the actual user
 292    executable and any needed shared libraries and then sends
 293    itself a SIGTRAP.
 294
 295    At that point we discover the names of all shared libraries and
 296    read their symbols in.
 297
 298    FIXME
 299
 300    This code does not properly handle hitting breakpoints which the
 301    user might have set in the rld itself.  Proper handling would have
 302    to check if the SIGTRAP happened due to a kill call.
 303
 304    Also, what if child has exit()ed?  Must exit loop somehow.  */
 305
 306 static void
 307 osf_solib_create_inferior_hook (void)
 308 {
 309   /* If we are attaching to the inferior, the shared libraries
 310      have already been mapped, so nothing more to do.  */
 311   if (attach_flag)
 312     return;
 313
 314   /* Nothing to do for statically bound executables.  */
 315
 316   if (symfile_objfile == NULL
 317       || symfile_objfile->obfd == NULL
 318       || ((bfd_get_file_flags (symfile_objfile->obfd) & DYNAMIC) == 0))
 319     return;
 320
 321   /* Now run the target.  It will eventually get a SIGTRAP, at
 322      which point all of the libraries will have been mapped in and we
 323      can go groveling around in the rld structures to find
 324      out what we need to know about them. */
 325
 326   clear_proceed_status ();
 327   stop_soon = STOP_QUIETLY;
 328   stop_signal = TARGET_SIGNAL_0;
 329   do
 330     {
 331       target_resume (minus_one_ptid, 0, stop_signal);
 332       wait_for_inferior (0);
 333     }
 334   while (stop_signal != TARGET_SIGNAL_TRAP);
 335
 336   /*  solib_add will call reinit_frame_cache.
 337      But we are stopped in the runtime loader and we do not have symbols
 338      for the runtime loader. So heuristic_proc_start will be called
 339      and will put out an annoying warning.
 340      Delaying the resetting of stop_soon until after symbol loading
 341      suppresses the warning.  */
 342   solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
 343   stop_soon = NO_STOP_QUIETLY;
 344 }
 345
 346 /* target_so_ops callback.  Do additional symbol handling, lookup, etc. after
 347    symbols for a shared object have been loaded.  */
 348
 349 static void
 350 osf_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
 358 static int
 359 open_map (struct read_map_ctxt *ctxt)
 360 {
 361 #ifdef USE_LDR_ROUTINES
 362   /* Note: As originally written, ldr_my_process() was used to obtain
 363      the value for ctxt->proc.  This is incorrect, however, since
 364      ldr_my_process() retrieves the "unique identifier" associated
 365      with the current process (i.e. GDB) and not the one being
 366      debugged.  Presumably, the pid of the process being debugged is
 367      compatible with the "unique identifier" used by the ldr_
 368      routines, so we use that.  */
 369   ctxt->proc = ptid_get_pid (inferior_ptid);
 370   if (ldr_xattach (ctxt->proc) != 0)
 371     return 0;
 372   ctxt->next = LDR_NULL_MODULE;
 373 #else
 374   CORE_ADDR ldr_context_addr, prev, next;
 375   ldr_context_t ldr_context;
 376
 377   if (target_read_memory ((CORE_ADDR) RLD_CONTEXT_ADDRESS,
 378                           (char *) &ldr_context_addr,
 379                           sizeof (CORE_ADDR)) != 0)
 380     return 0;
 381   if (target_read_memory (ldr_context_addr,
 382                           (char *) &ldr_context,
 383                           sizeof (ldr_context_t)) != 0)
 384     return 0;
 385   ctxt->next = ldr_context.head;
 386   ctxt->tail = ldr_context.tail;
 387 #endif
 388   return 1;
 389 }
 390
 391 /* Initialize SO to have module NAME, /sbin/loader indicator ISLOADR, and
 392    space for NSECS sections.  */
 393
 394 static void
 395 init_so (struct so_list *so, char *name, int isloader, int nsecs)
 396 {
 397   int namelen, i;
 398
 399   /* solib.c requires various fields to be initialized to 0.  */
 400   memset (so, 0, sizeof *so);
 401
 402   /* Copy the name.  */
 403   namelen = strlen (name);
 404   if (namelen >= SO_NAME_MAX_PATH_SIZE)
 405     namelen = SO_NAME_MAX_PATH_SIZE - 1;
 406
 407   memcpy (so->so_original_name, name, namelen);
 408   so->so_original_name[namelen] = '\0';
 409   memcpy (so->so_name, so->so_original_name, namelen + 1);
 410
 411   /* Allocate section space.  */
 412   so->lm_info = xmalloc ((unsigned) &(((struct lm_info *)0)->secs) +
 413                          nsecs * sizeof *so->lm_info);
 414   so->lm_info->isloader = isloader;
 415   so->lm_info->nsecs = nsecs;
 416   for (i = 0; i < nsecs; i++)
 417     so->lm_info->secs[i].name = NULL;
 418 }
 419
 420 /* Initialize SO's section SECIDX with name address NAMEADDR, name string
 421    NAME, default virtual address VADDR, and actual virtual address
 422    MAPADDR.  */
 423
 424 static void
 425 init_sec (struct so_list *so, int secidx, CORE_ADDR nameaddr,
 426           const char *name, CORE_ADDR vaddr, CORE_ADDR mapaddr)
 427 {
 428   struct lm_sec *lms;
 429
 430   lms = so->lm_info->secs + secidx;
 431   lms->nameaddr = nameaddr;
 432   lms->name = name;
 433   lms->offset = mapaddr - vaddr;
 434 }
 435
 436 /* If there are more elements starting at CTXT in inferior's module list,
 437    store the next element in SO, advance CTXT to the next element, and return
 438    1, else return 0.  */
 439
 440 static int
 441 read_map (struct read_map_ctxt *ctxt, struct so_list *so)
 442 {
 443   ldr_module_info_t minf;
 444   ldr_region_info_t rinf;
 445
 446 #ifdef USE_LDR_ROUTINES
 447   size_t size;
 448   ldr_region_t i;
 449
 450   /* Retrieve the next element.  */
 451   if (ldr_next_module (ctxt->proc, &ctxt->next) != 0)
 452     return 0;
 453   if (ctxt->next == LDR_NULL_MODULE)
 454     return 0;
 455   if (ldr_inq_module (ctxt->proc, ctxt->next, &minf, sizeof minf, &size) != 0)
 456     return 0;
 457
 458   /* Initialize the module name and section count.  */
 459   init_so (so, minf.lmi_name, 0, minf.lmi_nregion);
 460
 461   /* Retrieve section names and offsets.  */
 462   for (i = 0; i < minf.lmi_nregion; i++)
 463     {
 464       if (ldr_inq_region (ctxt->proc, ctxt->next, i, &rinf,
 465                           sizeof rinf, &size) != 0)
 466         goto err;
 467       init_sec (so, (int) i, 0, xstrdup (rinf.lri_name),
 468                 (CORE_ADDR) rinf.lri_vaddr, (CORE_ADDR) rinf.lri_mapaddr);
 469     }
 470   lm_secs_sort (so->lm_info);
 471 #else
 472   char *name;
 473   int errcode, i;
 474
 475   /* Retrieve the next element.  */
 476   if (!ctxt->next)
 477     return 0;
 478   if (target_read_memory (ctxt->next, (char *) &minf, sizeof minf) != 0)
 479     return 0;
 480   if (ctxt->next == ctxt->tail)
 481     ctxt->next = 0;
 482   else
 483     ctxt->next = minf.next;
 484
 485   /* Initialize the module name and section count.  */
 486   target_read_string (minf.module_name, &name, PATH_MAX, &errcode);
 487   if (errcode != 0)
 488     return 0;
 489   init_so (so, name, !minf.modinfo_addr, minf.region_count);
 490   xfree (name);
 491
 492   /* Retrieve section names and offsets.  */
 493   for (i = 0; i < minf.region_count; i++)
 494     {
 495       if (target_read_memory (minf.regioninfo_addr + i * sizeof rinf,
 496                               (char *) &rinf, sizeof rinf) != 0)
 497         goto err;
 498       init_sec (so, i, rinf.regionname_addr, NULL, rinf.vaddr, rinf.mapaddr);
 499     }
 500 #endif   /* !USE_LDR_ROUTINES */
 501   return 1;
 502
 503  err:
 504   osf_free_so (so);
 505   return 0;
 506 }
 507
 508 /* Free resources allocated by open_map (CTXT).  */
 509
 510 static void
 511 close_map (struct read_map_ctxt *ctxt)
 512 {
 513 #ifdef USE_LDR_ROUTINES
 514   ldr_xdetach (ctxt->proc);
 515 #endif
 516 }
 517
 518 /* target_so_ops callback.  Return a list of shared objects currently loaded
 519    in the inferior.  */
 520
 521 static struct so_list *
 522 osf_current_sos (void)
 523 {
 524   struct so_list *head = NULL, *tail, *newtail, so;
 525   struct read_map_ctxt ctxt;
 526   int skipped_main;
 527
 528   if (!open_map (&ctxt))
 529     return NULL;
 530
 531   /* Read subsequent elements.  */
 532   for (skipped_main = 0;;)
 533     {
 534       if (!read_map (&ctxt, &so))
 535         break;
 536
 537       /* Skip the main program module, which is first in the list after
 538          /sbin/loader.  */
 539       if (!so.lm_info->isloader && !skipped_main)
 540         {
 541           osf_free_so (&so);
 542           skipped_main = 1;
 543           continue;
 544         }
 545
 546       newtail = xmalloc (sizeof *newtail);
 547       if (!head)
 548         head = newtail;
 549       else
 550         tail->next = newtail;
 551       tail = newtail;
 552
 553       memcpy (tail, &so, sizeof so);
 554       tail->next = NULL;
 555     }
 556
 557   close_map (&ctxt);
 558   return head;
 559 }
 560
 561 /* target_so_ops callback.  Attempt to locate and open the main symbol
 562    file.  */
 563
 564 static int
 565 osf_open_symbol_file_object (void *from_ttyp)
 566 {
 567   struct read_map_ctxt ctxt;
 568   struct so_list so;
 569   int found;
 570
 571   if (symfile_objfile)
 572     if (!query ("Attempt to reload symbols from process? "))
 573       return 0;
 574
 575   /* The first module after /sbin/loader is the main program.  */
 576   if (!open_map (&ctxt))
 577     return 0;
 578   for (found = 0; !found;)
 579     {
 580       if (!read_map (&ctxt, &so))
 581         break;
 582       found = !so.lm_info->isloader;
 583       osf_free_so (&so);
 584     }
 585   close_map (&ctxt);
 586
 587   if (found)
 588     symbol_file_add_main (so.so_name, *(int *) from_ttyp);
 589   return found;
 590 }
 591
 592 /* target_so_ops callback.  Return whether PC is in the dynamic linker.  */
 593
 594 static int
 595 osf_in_dynsym_resolve_code (CORE_ADDR pc)
 596 {
 597   /* This function currently always return False. This is a temporary
 598      solution which only consequence is to introduce a minor incovenience
 599      for the user: When stepping inside a subprogram located in a shared
 600      library, gdb might stop inside the dynamic loader code instead of
 601      inside the subprogram itself. See the explanations in infrun.c about
 602      the IN_SOLIB_DYNSYM_RESOLVE_CODE macro for more details. */
 603   return 0;
 604 }
 605
 606 static struct target_so_ops osf_so_ops;
 607
 608 void
 609 _initialize_osf_solib (void)
 610 {
 611   osf_so_ops.relocate_section_addresses = osf_relocate_section_addresses;
 612   osf_so_ops.free_so = osf_free_so;
 613   osf_so_ops.clear_solib = osf_clear_solib;
 614   osf_so_ops.solib_create_inferior_hook = osf_solib_create_inferior_hook;
 615   osf_so_ops.special_symbol_handling = osf_special_symbol_handling;
 616   osf_so_ops.current_sos = osf_current_sos;
 617   osf_so_ops.open_symbol_file_object = osf_open_symbol_file_object;
 618   osf_so_ops.in_dynsym_resolve_code = osf_in_dynsym_resolve_code;
 619
 620   /* FIXME: Don't do this here.  *_gdbarch_init() should set so_ops. */
 621   current_target_so_ops = &osf_so_ops;
 622 }