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
   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   /* Nothing to do for statically bound executables.  */
 310
 311   if (symfile_objfile == NULL
 312       || symfile_objfile->obfd == NULL
 313       || ((bfd_get_file_flags (symfile_objfile->obfd) & DYNAMIC) == 0))
 314     return;
 315
 316   /* Now run the target.  It will eventually get a SIGTRAP, at
 317      which point all of the libraries will have been mapped in and we
 318      can go groveling around in the rld structures to find
 319      out what we need to know about them. */
 320
 321   clear_proceed_status ();
 322   stop_soon = STOP_QUIETLY;
 323   stop_signal = TARGET_SIGNAL_0;
 324   do
 325     {
 326       target_resume (minus_one_ptid, 0, stop_signal);
 327       wait_for_inferior ();
 328     }
 329   while (stop_signal != TARGET_SIGNAL_TRAP);
 330
 331   /*  solib_add will call reinit_frame_cache.
 332      But we are stopped in the runtime loader and we do not have symbols
 333      for the runtime loader. So heuristic_proc_start will be called
 334      and will put out an annoying warning.
 335      Delaying the resetting of stop_soon until after symbol loading
 336      suppresses the warning.  */
 337   solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
 338   stop_soon = NO_STOP_QUIETLY;
 339
 340   /* Enable breakpoints disabled (unnecessarily) by clear_solib().  */
 341   re_enable_breakpoints_in_shlibs ();
 342 }
 343
 344 /* target_so_ops callback.  Do additional symbol handling, lookup, etc. after
 345    symbols for a shared object have been loaded.  */
 346
 347 static void
 348 osf_special_symbol_handling (void)
 349 {
 350   return;
 351 }
 352
 353 /* Initialize CTXT in preparation for iterating through the inferior's module
 354    list using read_map().  Return success.  */
 355
 356 static int
 357 open_map (struct read_map_ctxt *ctxt)
 358 {
 359 #ifdef USE_LDR_ROUTINES
 360   /* Note: As originally written, ldr_my_process() was used to obtain
 361      the value for ctxt->proc.  This is incorrect, however, since
 362      ldr_my_process() retrieves the "unique identifier" associated
 363      with the current process (i.e. GDB) and not the one being
 364      debugged.  Presumably, the pid of the process being debugged is
 365      compatible with the "unique identifier" used by the ldr_
 366      routines, so we use that.  */
 367   ctxt->proc = ptid_get_pid (inferior_ptid);
 368   if (ldr_xattach (ctxt->proc) != 0)
 369     return 0;
 370   ctxt->next = LDR_NULL_MODULE;
 371 #else
 372   CORE_ADDR ldr_context_addr, prev, next;
 373   ldr_context_t ldr_context;
 374
 375   if (target_read_memory ((CORE_ADDR) RLD_CONTEXT_ADDRESS,
 376                           (char *) &ldr_context_addr,
 377                           sizeof (CORE_ADDR)) != 0)
 378     return 0;
 379   if (target_read_memory (ldr_context_addr,
 380                           (char *) &ldr_context,
 381                           sizeof (ldr_context_t)) != 0)
 382     return 0;
 383   ctxt->next = ldr_context.head;
 384   ctxt->tail = ldr_context.tail;
 385 #endif
 386   return 1;
 387 }
 388
 389 /* Initialize SO to have module NAME, /sbin/loader indicator ISLOADR, and
 390    space for NSECS sections.  */
 391
 392 static void
 393 init_so (struct so_list *so, char *name, int isloader, int nsecs)
 394 {
 395   int namelen, i;
 396
 397   /* solib.c requires various fields to be initialized to 0.  */
 398   memset (so, 0, sizeof *so);
 399
 400   /* Copy the name.  */
 401   namelen = strlen (name);
 402   if (namelen >= SO_NAME_MAX_PATH_SIZE)
 403     namelen = SO_NAME_MAX_PATH_SIZE - 1;
 404
 405   memcpy (so->so_original_name, name, namelen);
 406   so->so_original_name[namelen] = '\0';
 407   memcpy (so->so_name, so->so_original_name, namelen + 1);
 408
 409   /* Allocate section space.  */
 410   so->lm_info = xmalloc ((unsigned) &(((struct lm_info *)0)->secs) +
 411                          nsecs * sizeof *so->lm_info);
 412   so->lm_info->isloader = isloader;
 413   so->lm_info->nsecs = nsecs;
 414   for (i = 0; i < nsecs; i++)
 415     so->lm_info->secs[i].name = NULL;
 416 }
 417
 418 /* Initialize SO's section SECIDX with name address NAMEADDR, name string
 419    NAME, default virtual address VADDR, and actual virtual address
 420    MAPADDR.  */
 421
 422 static void
 423 init_sec (struct so_list *so, int secidx, CORE_ADDR nameaddr,
 424           const char *name, CORE_ADDR vaddr, CORE_ADDR mapaddr)
 425 {
 426   struct lm_sec *lms;
 427
 428   lms = so->lm_info->secs + secidx;
 429   lms->nameaddr = nameaddr;
 430   lms->name = name;
 431   lms->offset = mapaddr - vaddr;
 432 }
 433
 434 /* If there are more elements starting at CTXT in inferior's module list,
 435    store the next element in SO, advance CTXT to the next element, and return
 436    1, else return 0.  */
 437
 438 static int
 439 read_map (struct read_map_ctxt *ctxt, struct so_list *so)
 440 {
 441   ldr_module_info_t minf;
 442   ldr_region_info_t rinf;
 443
 444 #ifdef USE_LDR_ROUTINES
 445   size_t size;
 446   ldr_region_t i;
 447
 448   /* Retrieve the next element.  */
 449   if (ldr_next_module (ctxt->proc, &ctxt->next) != 0)
 450     return 0;
 451   if (ctxt->next == LDR_NULL_MODULE)
 452     return 0;
 453   if (ldr_inq_module (ctxt->proc, ctxt->next, &minf, sizeof minf, &size) != 0)
 454     return 0;
 455
 456   /* Initialize the module name and section count.  */
 457   init_so (so, minf.lmi_name, 0, minf.lmi_nregion);
 458
 459   /* Retrieve section names and offsets.  */
 460   for (i = 0; i < minf.lmi_nregion; i++)
 461     {
 462       if (ldr_inq_region (ctxt->proc, ctxt->next, i, &rinf,
 463                           sizeof rinf, &size) != 0)
 464         goto err;
 465       init_sec (so, (int) i, 0, xstrdup (rinf.lri_name),
 466                 (CORE_ADDR) rinf.lri_vaddr, (CORE_ADDR) rinf.lri_mapaddr);
 467     }
 468   lm_secs_sort (so->lm_info);
 469 #else
 470   char *name;
 471   int errcode, i;
 472
 473   /* Retrieve the next element.  */
 474   if (!ctxt->next)
 475     return 0;
 476   if (target_read_memory (ctxt->next, (char *) &minf, sizeof minf) != 0)
 477     return 0;
 478   if (ctxt->next == ctxt->tail)
 479     ctxt->next = 0;
 480   else
 481     ctxt->next = minf.next;
 482
 483   /* Initialize the module name and section count.  */
 484   target_read_string (minf.module_name, &name, PATH_MAX, &errcode);
 485   if (errcode != 0)
 486     return 0;
 487   init_so (so, name, !minf.modinfo_addr, minf.region_count);
 488   xfree (name);
 489
 490   /* Retrieve section names and offsets.  */
 491   for (i = 0; i < minf.region_count; i++)
 492     {
 493       if (target_read_memory (minf.regioninfo_addr + i * sizeof rinf,
 494                               (char *) &rinf, sizeof rinf) != 0)
 495         goto err;
 496       init_sec (so, i, rinf.regionname_addr, NULL, rinf.vaddr, rinf.mapaddr);
 497     }
 498 #endif   /* !USE_LDR_ROUTINES */
 499   return 1;
 500
 501  err:
 502   osf_free_so (so);
 503   return 0;
 504 }
 505
 506 /* Free resources allocated by open_map (CTXT).  */
 507
 508 static void
 509 close_map (struct read_map_ctxt *ctxt)
 510 {
 511 #ifdef USE_LDR_ROUTINES
 512   ldr_xdetach (ctxt->proc);
 513 #endif
 514 }
 515
 516 /* target_so_ops callback.  Return a list of shared objects currently loaded
 517    in the inferior.  */
 518
 519 static struct so_list *
 520 osf_current_sos (void)
 521 {
 522   struct so_list *head = NULL, *tail, *newtail, so;
 523   struct read_map_ctxt ctxt;
 524   int skipped_main;
 525
 526   if (!open_map (&ctxt))
 527     return NULL;
 528
 529   /* Read subsequent elements.  */
 530   for (skipped_main = 0;;)
 531     {
 532       if (!read_map (&ctxt, &so))
 533         break;
 534
 535       /* Skip the main program module, which is first in the list after
 536          /sbin/loader.  */
 537       if (!so.lm_info->isloader && !skipped_main)
 538         {
 539           osf_free_so (&so);
 540           skipped_main = 1;
 541           continue;
 542         }
 543
 544       newtail = xmalloc (sizeof *newtail);
 545       if (!head)
 546         head = newtail;
 547       else
 548         tail->next = newtail;
 549       tail = newtail;
 550
 551       memcpy (tail, &so, sizeof so);
 552       tail->next = NULL;
 553     }
 554
 555   close_map (&ctxt);
 556   return head;
 557 }
 558
 559 /* target_so_ops callback.  Attempt to locate and open the main symbol
 560    file.  */
 561
 562 static int
 563 osf_open_symbol_file_object (void *from_ttyp)
 564 {
 565   struct read_map_ctxt ctxt;
 566   struct so_list so;
 567   int found;
 568
 569   if (symfile_objfile)
 570     if (!query ("Attempt to reload symbols from process? "))
 571       return 0;
 572
 573   /* The first module after /sbin/loader is the main program.  */
 574   if (!open_map (&ctxt))
 575     return 0;
 576   for (found = 0; !found;)
 577     {
 578       if (!read_map (&ctxt, &so))
 579         break;
 580       found = !so.lm_info->isloader;
 581       osf_free_so (&so);
 582     }
 583   close_map (&ctxt);
 584
 585   if (found)
 586     symbol_file_add_main (so.so_name, *(int *) from_ttyp);
 587   return found;
 588 }
 589
 590 /* target_so_ops callback.  Return whether PC is in the dynamic linker.  */
 591
 592 static int
 593 osf_in_dynsym_resolve_code (CORE_ADDR pc)
 594 {
 595   /* This function currently always return False. This is a temporary
 596      solution which only consequence is to introduce a minor incovenience
 597      for the user: When stepping inside a subprogram located in a shared
 598      library, gdb might stop inside the dynamic loader code instead of
 599      inside the subprogram itself. See the explanations in infrun.c about
 600      the IN_SOLIB_DYNSYM_RESOLVE_CODE macro for more details. */
 601   return 0;
 602 }
 603
 604 static struct target_so_ops osf_so_ops;
 605
 606 void
 607 _initialize_osf_solib (void)
 608 {
 609   osf_so_ops.relocate_section_addresses = osf_relocate_section_addresses;
 610   osf_so_ops.free_so = osf_free_so;
 611   osf_so_ops.clear_solib = osf_clear_solib;
 612   osf_so_ops.solib_create_inferior_hook = osf_solib_create_inferior_hook;
 613   osf_so_ops.special_symbol_handling = osf_special_symbol_handling;
 614   osf_so_ops.current_sos = osf_current_sos;
 615   osf_so_ops.open_symbol_file_object = osf_open_symbol_file_object;
 616   osf_so_ops.in_dynsym_resolve_code = osf_in_dynsym_resolve_code;
 617
 618   /* FIXME: Don't do this here.  *_gdbarch_init() should set so_ops. */
 619   current_target_so_ops = &osf_so_ops;
 620 }