gdb/objfiles.c

   1 /* GDB routines for manipulating objfiles.
   2    Copyright 1992 Free Software Foundation, Inc.
   3    Contributed by Cygnus Support, using pieces from other GDB modules.
   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 2 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, write to the Free Software
  19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 /* This file contains support routines for creating, manipulating, and
  22    destroying objfile structures. */
  23
  24 #include "defs.h"
  25 #include "bfd.h"                /* Binary File Description */
  26 #include "symtab.h"
  27 #include "symfile.h"
  28 #include "objfiles.h"
  29
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32 #include <fcntl.h>
  33 #include <obstack.h>
  34
  35 /* Prototypes for local functions */
  36
  37 static int
  38 open_mapped_file PARAMS ((char *filename, long mtime, int mapped));
  39
  40 static CORE_ADDR
  41 map_to_address PARAMS ((void));
  42
  43 /* Externally visible variables that are owned by this module.
  44    See declarations in objfile.h for more info. */
  45
  46 struct objfile *object_files;           /* Linked list of all objfiles */
  47 struct objfile *current_objfile;        /* For symbol file being read in */
  48 struct objfile *symfile_objfile;        /* Main symbol table loaded from */
  49
  50 int mapped_symbol_files;                /* Try to use mapped symbol files */
  51
  52 /* Given a pointer to an initialized bfd (ABFD) and a flag that indicates
  53    whether or not an objfile is to be mapped (MAPPED), allocate a new objfile
  54    struct, fill it in as best we can, link it into the list of all known
  55    objfiles, and return a pointer to the new objfile struct. */
  56
  57 struct objfile *
  58 allocate_objfile (abfd, mapped)
  59      bfd *abfd;
  60      int mapped;
  61 {
  62   struct objfile *objfile = NULL;
  63   int fd;
  64   void *md;
  65   CORE_ADDR mapto;
  66
  67   mapped |= mapped_symbol_files;
  68
  69 #if !defined(NO_MMALLOC) && defined(HAVE_MMAP)
  70
  71   /* If we can support mapped symbol files, try to open/reopen the mapped file
  72      that corresponds to the file from which we wish to read symbols.  If the
  73      objfile is to be mapped, we must malloc the structure itself using the
  74      mmap version, and arrange that all memory allocation for the objfile uses
  75      the mmap routines.  If we are reusing an existing mapped file, from which
  76      we get our objfile pointer, we have to make sure that we update the
  77      pointers to the alloc/free functions in the obstack, in case these
  78      functions have moved within the current gdb. */
  79
  80   fd = open_mapped_file (bfd_get_filename (abfd), bfd_get_mtime (abfd),
  81                          mapped);
  82   if (fd >= 0)
  83     {
  84       if (((mapto = map_to_address ()) == 0) ||
  85           ((md = mmalloc_attach (fd, (void *) mapto)) == NULL))
  86         {
  87           close (fd);
  88         }
  89       else if ((objfile = (struct objfile *) mmalloc_getkey (md, 0)) != NULL)
  90         {
  91           /* Update memory corruption handler function addresses. */
  92           init_malloc (md);
  93           objfile -> md = md;
  94           /* Update pointers to functions to *our* copies */
  95           obstack_chunkfun (&objfile -> psymbol_obstack, xmmalloc);
  96           obstack_freefun (&objfile -> psymbol_obstack, mfree);
  97           obstack_chunkfun (&objfile -> symbol_obstack, xmmalloc);
  98           obstack_freefun (&objfile -> symbol_obstack, mfree);
  99           obstack_chunkfun (&objfile -> type_obstack, xmmalloc);
 100           obstack_freefun (&objfile -> type_obstack, mfree);
 101         }
 102       else
 103         {
 104           /* Set up to detect internal memory corruption.  MUST be done before
 105              the first malloc.  See comments in init_malloc() and mmcheck(). */
 106           init_malloc (md);
 107           objfile = (struct objfile *) xmmalloc (md, sizeof (struct objfile));
 108           (void) memset (objfile, 0, sizeof (struct objfile));
 109           objfile -> md = md;
 110           objfile -> flags |= OBJF_MAPPED;
 111           mmalloc_setkey (objfile -> md, 0, objfile);
 112           obstack_full_begin (&objfile -> psymbol_obstack, 0, 0,
 113                               xmmalloc, mfree, objfile -> md,
 114                               OBSTACK_MMALLOC_LIKE);
 115           obstack_full_begin (&objfile -> symbol_obstack, 0, 0,
 116                               xmmalloc, mfree, objfile -> md,
 117                               OBSTACK_MMALLOC_LIKE);
 118           obstack_full_begin (&objfile -> type_obstack, 0, 0,
 119                               xmmalloc, mfree, objfile -> md,
 120                               OBSTACK_MMALLOC_LIKE);
 121         }
 122     }
 123
 124   if (mapped && (objfile == NULL))
 125     {
 126       warning ("symbol table for '%s' will not be mapped",
 127                bfd_get_filename (abfd));
 128     }
 129
 130 #else   /* defined(NO_MMALLOC) || !defined(HAVE_MMAP) */
 131
 132   if (mapped)
 133     {
 134       warning ("this version of gdb does not support mapped symbol tables.");
 135
 136       /* Turn off the global flag so we don't try to do mapped symbol tables
 137          any more, which shuts up gdb unless the user specifically gives the
 138          "mapped" keyword again. */
 139
 140       mapped_symbol_files = 0;
 141     }
 142
 143 #endif  /* !defined(NO_MMALLOC) && defined(HAVE_MMAP) */
 144
 145   /* If we don't support mapped symbol files, didn't ask for the file to be
 146      mapped, or failed to open the mapped file for some reason, then revert
 147      back to an unmapped objfile. */
 148
 149   if (objfile == NULL)
 150     {
 151       objfile = (struct objfile *) xmalloc (sizeof (struct objfile));
 152       (void) memset (objfile, 0, sizeof (struct objfile));
 153       objfile -> md = NULL;
 154       obstack_full_begin (&objfile -> psymbol_obstack, 0, 0, xmalloc, free,
 155                           (void *) 0, 0);
 156       obstack_full_begin (&objfile -> symbol_obstack, 0, 0, xmalloc, free,
 157                           (void *) 0, 0);
 158       obstack_full_begin (&objfile -> type_obstack, 0, 0, xmalloc, free,
 159                           (void *) 0, 0);
 160
 161     }
 162
 163   /* Update the per-objfile information that comes from the bfd, ensuring
 164      that any data that is reference is saved in the per-objfile data
 165      region. */
 166
 167   objfile -> obfd = abfd;
 168   objfile -> name = mstrsave (objfile -> md, bfd_get_filename (abfd));
 169   objfile -> mtime = bfd_get_mtime (abfd);
 170
 171   /* Push this file onto the head of the linked list of other such files. */
 172
 173   objfile -> next = object_files;
 174   object_files = objfile;
 175
 176   return (objfile);
 177 }
 178
 179
 180 /* Destroy an objfile and all the symtabs and psymtabs under it.  Note
 181    that as much as possible is allocated on the symbol_obstack and
 182    psymbol_obstack, so that the memory can be efficiently freed.
 183
 184    Things which we do NOT free because they are not in malloc'd memory
 185    or not in memory specific to the objfile include:
 186
 187         objfile -> sf
 188
 189    */
 190
 191 void
 192 free_objfile (objfile)
 193      struct objfile *objfile;
 194 {
 195   struct objfile *ofp;
 196
 197   if (objfile -> sf != NULL)
 198     {
 199       (*objfile -> sf -> sym_finish) (objfile);
 200     }
 201   if (objfile -> name != NULL)
 202     {
 203       mfree (objfile -> md, objfile -> name);
 204     }
 205   if (objfile -> obfd != NULL)
 206     {
 207       bfd_close (objfile -> obfd);
 208     }
 209
 210   /* Remove it from the chain of all objfiles.  */
 211
 212   if (object_files == objfile)
 213     {
 214       object_files = objfile -> next;
 215     }
 216   else
 217     {
 218       for (ofp = object_files; ofp; ofp = ofp -> next)
 219         {
 220           if (ofp -> next == objfile)
 221             {
 222               ofp -> next = objfile -> next;
 223             }
 224         }
 225     }
 226
 227   obstack_free (&objfile -> psymbol_obstack, 0);
 228   obstack_free (&objfile -> symbol_obstack, 0);
 229   obstack_free (&objfile -> type_obstack, 0);
 230
 231 #if 0   /* FIXME!! */
 232
 233   /* Before the symbol table code was redone to make it easier to
 234      selectively load and remove information particular to a specific
 235      linkage unit, gdb used to do these things whenever the monolithic
 236      symbol table was blown away.  How much still needs to be done
 237      is unknown, but we play it safe for now and keep each action until
 238      it is shown to be no longer needed. */
 239
 240   clear_symtab_users_once ();
 241 #if defined (CLEAR_SOLIB)
 242   CLEAR_SOLIB ();
 243 #endif
 244   clear_pc_function_cache ();
 245
 246 #endif
 247
 248   /* The last thing we do is free the objfile struct itself */
 249
 250   mfree (objfile -> md, objfile);
 251 }
 252
 253
 254 /* Free all the object files at once.  */
 255
 256 void
 257 free_all_objfiles ()
 258 {
 259   struct objfile *objfile, *temp;
 260
 261   ALL_OBJFILES_SAFE (objfile, temp)
 262     {
 263       free_objfile (objfile);
 264     }
 265 }
 266
 267 /* Many places in gdb want to test just to see if we have any partial
 268    symbols available.  This function returns zero if none are currently
 269    available, nonzero otherwise. */
 270
 271 int
 272 have_partial_symbols ()
 273 {
 274   struct objfile *ofp;
 275   int havethem = 0;
 276
 277   for (ofp = object_files; ofp; ofp = ofp -> next)
 278     {
 279       if (ofp -> psymtabs != NULL)
 280         {
 281           havethem++;
 282           break;
 283         }
 284     }
 285   return (havethem);
 286 }
 287
 288 /* Many places in gdb want to test just to see if we have any full
 289    symbols available.  This function returns zero if none are currently
 290    available, nonzero otherwise. */
 291
 292 int
 293 have_full_symbols ()
 294 {
 295   struct objfile *ofp;
 296   int havethem = 0;
 297
 298   for (ofp = object_files; ofp; ofp = ofp -> next)
 299     {
 300       if (ofp -> symtabs != NULL)
 301         {
 302           havethem++;
 303           break;
 304         }
 305     }
 306   return (havethem);
 307 }
 308
 309 /* Many places in gdb want to test just to see if we have any minimal
 310    symbols available.  This function returns zero if none are currently
 311    available, nonzero otherwise. */
 312
 313 int
 314 have_minimal_symbols ()
 315 {
 316   struct objfile *ofp;
 317   int havethem = 0;
 318
 319   for (ofp = object_files; ofp; ofp = ofp -> next)
 320     {
 321       if (ofp -> msymbols != NULL)
 322         {
 323           havethem++;
 324           break;
 325         }
 326     }
 327   return (havethem);
 328 }
 329
 330 /* Call the function specified by FUNC for each currently available objfile,
 331    for as long as this function continues to return NULL.  If the function
 332    ever returns non-NULL, then the iteration over the objfiles is terminated,
 333    and the result is returned to the caller.  The function called has full
 334    control over the form and content of the information returned via the
 335    non-NULL result, which may be as simple as a pointer to the objfile that
 336    the iteration terminated on, or as complex as a pointer to a private
 337    structure containing multiple results. */
 338
 339 PTR
 340 iterate_over_objfiles (func, arg1, arg2, arg3)
 341      PTR (*func) PARAMS ((struct objfile *, PTR, PTR, PTR));
 342      PTR arg1;
 343      PTR arg2;
 344      PTR arg3;
 345 {
 346   register struct objfile *objfile;
 347   PTR result = NULL;
 348
 349   for (objfile = object_files;
 350        objfile != NULL && result == NULL;
 351        objfile = objfile -> next)
 352     {
 353       result = (*func)(objfile, arg1, arg2, arg3);
 354     }
 355   return (result);
 356 }
 357
 358 /* Call the function specified by FUNC for each currently available symbol
 359    table, for as long as this function continues to return NULL.  If the
 360    function ever returns non-NULL, then the iteration over the symbol tables
 361    is terminated, and the result is returned to the caller.  The function
 362    called has full control over the form and content of the information
 363    returned via the non-NULL result, which may be as simple as a pointer
 364    to the symtab that the iteration terminated on, or as complex as a
 365    pointer to a private structure containing multiple results. */
 366
 367 PTR
 368 iterate_over_symtabs (func, arg1, arg2, arg3)
 369      PTR (*func) PARAMS ((struct objfile *, struct symtab *, PTR, PTR, PTR));
 370      PTR arg1;
 371      PTR arg2;
 372      PTR arg3;
 373 {
 374   register struct objfile *objfile;
 375   register struct symtab *symtab;
 376   PTR result = NULL;
 377
 378   for (objfile = object_files;
 379        objfile != NULL && result == NULL;
 380        objfile = objfile -> next)
 381     {
 382       for (symtab = objfile -> symtabs;
 383            symtab != NULL && result == NULL;
 384            symtab = symtab -> next)
 385         {
 386           result = (*func)(objfile, symtab, arg1, arg2, arg3);
 387         }
 388     }
 389   return (result);
 390 }
 391
 392 /* Call the function specified by FUNC for each currently available partial
 393    symbol table, for as long as this function continues to return NULL.  If
 394    the function ever returns non-NULL, then the iteration over the partial
 395    symbol tables is terminated, and the result is returned to the caller.
 396
 397    The function called has full control over the form and content of the
 398    information returned via the non-NULL result, which may be as simple as a
 399    pointer to the partial symbol table that the iteration terminated on, or
 400    as complex as a pointer to a private structure containing multiple
 401    results. */
 402
 403 PTR
 404 iterate_over_psymtabs (func, arg1, arg2, arg3)
 405      PTR (*func) PARAMS ((struct objfile *, struct partial_symtab *,
 406                           PTR, PTR, PTR));
 407      PTR arg1;
 408      PTR arg2;
 409      PTR arg3;
 410 {
 411   register struct objfile *objfile;
 412   register struct partial_symtab *psymtab;
 413   PTR result = NULL;
 414
 415   for (objfile = object_files;
 416        objfile != NULL && result == NULL;
 417        objfile = objfile -> next)
 418     {
 419       for (psymtab = objfile -> psymtabs;
 420            psymtab != NULL && result == NULL;
 421            psymtab = psymtab -> next)
 422         {
 423           result = (*func)(objfile, psymtab, arg1, arg2, arg3);
 424         }
 425     }
 426   return (result);
 427 }
 428
 429
 430 /* Look for a mapped symbol file that corresponds to FILENAME and is more
 431    recent than MTIME.  If MAPPED is nonzero, the user has asked that gdb
 432    use a mapped symbol file for this file, so create a new one if one does
 433    not currently exist.
 434
 435    If found, then return an open file descriptor for the file, otherwise
 436    return -1.
 437
 438    This routine is responsible for implementing the policy that generates
 439    the name of the mapped symbol file from the name of a file containing
 440    symbols that gdb would like to read. */
 441
 442 static int
 443 open_mapped_file (filename, mtime, mapped)
 444      char *filename;
 445      long mtime;
 446      int mapped;
 447 {
 448   int fd;
 449   char *symfilename;
 450   struct stat sbuf;
 451
 452   /* For now, all we do is look in the local directory for a file with
 453      the name of the base file and an extension of ".syms" */
 454
 455   symfilename = concat ("./", basename (filename), ".syms", (char *) NULL);
 456
 457   /* Check to see if the desired file already exists and is more recent than
 458      the corresponding base file (specified by the passed MTIME parameter).
 459      The open will fail if the file does not already exist. */
 460
 461   if ((fd = open (symfilename, O_RDWR)) >= 0)
 462     {
 463       if (fstat (fd, &sbuf) != 0)
 464         {
 465           close (fd);
 466           perror_with_name (symfilename);
 467         }
 468       else if (sbuf.st_mtime > mtime)
 469         {
 470           return (fd);
 471         }
 472       else
 473         {
 474           close (fd);
 475           fd = -1;
 476         }
 477     }
 478
 479   /* Either the file does not already exist, or the base file has changed
 480      since it was created.  In either case, if the user has specified use of
 481      a mapped file, then create a new mapped file, truncating any existing
 482      one.
 483
 484      In the case where there is an existing file, but it is out of date, and
 485      the user did not specify mapped, the existing file is just silently
 486      ignored.  Perhaps we should warn about this case (FIXME?).
 487
 488      By default the file is rw for everyone, with the user's umask taking
 489      care of turning off the permissions the user wants off. */
 490
 491   if (mapped)
 492     {
 493       fd = open (symfilename, O_RDWR | O_CREAT | O_TRUNC, 0666);
 494     }
 495
 496   return (fd);
 497 }
 498
 499 /* Return the base address at which we would like the next objfile's
 500    mapped data to start.
 501
 502    For now, we use the kludge that the configuration specifies a base
 503    address to which it is safe to map the first mmalloc heap, and an
 504    increment to add to this address for each successive heap.  There are
 505    a lot of issues to deal with here to make this work reasonably, including:
 506
 507      Avoid memory collisions with existing mapped address spaces
 508
 509      Reclaim address spaces when their mmalloc heaps are unmapped
 510
 511      When mmalloc heaps are shared between processes they have to be
 512      mapped at the same addresses in each
 513
 514      Once created, a mmalloc heap that is to be mapped back in must be
 515      mapped at the original address.  I.E. each objfile will expect to
 516      be remapped at it's original address.  This becomes a problem if
 517      the desired address is already in use.
 518
 519      etc, etc, etc.
 520
 521  */
 522
 523
 524 static CORE_ADDR
 525 map_to_address ()
 526 {
 527
 528 #if defined(MMAP_BASE_ADDRESS) && defined (MMAP_INCREMENT)
 529
 530   static CORE_ADDR next = MMAP_BASE_ADDRESS;
 531   CORE_ADDR mapto = next;
 532
 533   next += MMAP_INCREMENT;
 534   return (mapto);
 535
 536 #else
 537
 538   return (0);
 539
 540 #endif
 541
 542 }