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