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