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
   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., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, 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
  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   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"), 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
 235 static void
 236 osf_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
 259 static void
 260 osf_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
 277 static void
 278 osf_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
 308 static void
 309 osf_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 = STOP_QUIETLY;
 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 until after symbol loading
 338      suppresses the warning.  */
 339   solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
 340   stop_soon = NO_STOP_QUIETLY;
 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
 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 }