bfd/coff-stgo32.c

   1 /* BFD back-end for Intel 386 COFF files (DJGPP variant with a stub).
   2    Copyright 1997, 1998, 1999, 2000, 2001, 2002, 2005, 2006, 2007, 2009,
   3    2011  Free Software Foundation, Inc.
   4    Written by Robert Hoehne.
   5
   6    This file is part of BFD, the Binary File Descriptor library.
   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, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21    MA 02110-1301, USA.  */
  22
  23 /* This file handles now also stubbed coff images. The stub is a small
  24    DOS executable program before the coff image to load it in memory
  25    and execute it. This is needed, because DOS cannot run coff files.
  26
  27    All the functions below are called by the corresponding functions
  28    from coffswap.h.
  29    The only thing what they do is to adjust the information stored in
  30    the COFF file which are offset into the file.
  31    This is needed, because DJGPP uses a very special way to load and run
  32    the coff image. It loads the image in memory and assumes then, that the
  33    image had no stub by using the filepointers as pointers in the coff
  34    image and NOT in the file.
  35
  36    To be compatible with any existing executables I have fixed this
  37    here and NOT in the DJGPP startup code.  */
  38
  39 #define TARGET_SYM              go32stubbedcoff_vec
  40 #define TARGET_NAME             "coff-go32-exe"
  41 #define TARGET_UNDERSCORE       '_'
  42 #define COFF_GO32_EXE
  43 #define COFF_LONG_SECTION_NAMES
  44 #define COFF_SUPPORT_GNU_LINKONCE
  45 #define COFF_LONG_FILENAMES
  46
  47 #define COFF_SECTION_ALIGNMENT_ENTRIES \
  48 { COFF_SECTION_NAME_EXACT_MATCH (".data"), \
  49   COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 4 }, \
  50 { COFF_SECTION_NAME_EXACT_MATCH (".text"), \
  51   COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 4 }, \
  52 { COFF_SECTION_NAME_PARTIAL_MATCH (".debug"), \
  53   COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 0 }, \
  54 { COFF_SECTION_NAME_PARTIAL_MATCH (".gnu.linkonce.wi"), \
  55   COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 0 }
  56
  57 #include "bfd.h"
  58
  59 /* At first the prototypes.  */
  60
  61 static void
  62 adjust_filehdr_in_post PARAMS ((bfd *, PTR, PTR));
  63 static void
  64 adjust_filehdr_out_pre PARAMS ((bfd *, PTR, PTR));
  65 static void
  66 adjust_filehdr_out_post PARAMS ((bfd *, PTR, PTR));
  67 static void
  68 adjust_scnhdr_in_post PARAMS ((bfd *, PTR, PTR));
  69 static void
  70 adjust_scnhdr_out_pre PARAMS ((bfd *, PTR, PTR));
  71 static void
  72 adjust_scnhdr_out_post PARAMS ((bfd *, PTR, PTR));
  73 static void
  74 adjust_aux_in_post PARAMS ((bfd *, PTR, int, int, int, int, PTR));
  75 static void
  76 adjust_aux_out_pre PARAMS ((bfd *, PTR, int, int, int, int, PTR));
  77 static void
  78 adjust_aux_out_post PARAMS ((bfd *, PTR, int, int, int, int, PTR));
  79 static void
  80 create_go32_stub PARAMS ((bfd *));
  81
  82 /* All that ..._PRE and ...POST functions are called from the corresponding
  83    coff_swap... functions. The ...PRE functions are called at the beginning
  84    of the function and the ...POST functions at the end of the swap routines.  */
  85
  86 #define COFF_ADJUST_FILEHDR_IN_POST adjust_filehdr_in_post
  87 #define COFF_ADJUST_FILEHDR_OUT_PRE adjust_filehdr_out_pre
  88 #define COFF_ADJUST_FILEHDR_OUT_POST adjust_filehdr_out_post
  89
  90 #define COFF_ADJUST_SCNHDR_IN_POST adjust_scnhdr_in_post
  91 #define COFF_ADJUST_SCNHDR_OUT_PRE adjust_scnhdr_out_pre
  92 #define COFF_ADJUST_SCNHDR_OUT_POST adjust_scnhdr_out_post
  93
  94 #define COFF_ADJUST_AUX_IN_POST adjust_aux_in_post
  95 #define COFF_ADJUST_AUX_OUT_PRE adjust_aux_out_pre
  96 #define COFF_ADJUST_AUX_OUT_POST adjust_aux_out_post
  97
  98 static bfd_boolean
  99   go32_stubbed_coff_bfd_copy_private_bfd_data PARAMS ((bfd *, bfd *));
 100
 101 #define coff_bfd_copy_private_bfd_data go32_stubbed_coff_bfd_copy_private_bfd_data
 102
 103 #include "coff-i386.c"
 104
 105 /* This macro is used, because I cannot assume the endianness of the
 106    host system.  */
 107 #define _H(index) (H_GET_16 (abfd, (header + index * 2)))
 108
 109 /* These bytes are a 2048-byte DOS executable, which loads the COFF
 110    image into memory and then runs it. It is called 'stub'.  */
 111
 112 static const unsigned char stub_bytes[GO32_STUBSIZE] =
 113 {
 114 #include "go32stub.h"
 115 };
 116
 117 /*
 118    I have not commented each swap function below, because the
 119    technique is in any function the same. For the ...in function,
 120    all the pointers are adjusted by adding GO32_STUBSIZE and for the
 121    ...out function, it is subtracted first and after calling the
 122    standard swap function it is reset to the old value.  */
 123
 124 /* This macro is used for adjusting the filepointers, which
 125    is done only, if the pointer is nonzero.  */
 126
 127 #define ADJUST_VAL(val,diff) \
 128   if (val != 0) val += diff
 129
 130 static void
 131 adjust_filehdr_in_post  (abfd, src, dst)
 132      bfd *abfd ATTRIBUTE_UNUSED;
 133      PTR src;
 134      PTR dst;
 135 {
 136   FILHDR *filehdr_src = (FILHDR *) src;
 137   struct internal_filehdr *filehdr_dst = (struct internal_filehdr *) dst;
 138
 139   ADJUST_VAL (filehdr_dst->f_symptr, GO32_STUBSIZE);
 140
 141   /* Save now the stub to be used later.  Put the stub data to FILEHDR_DST
 142      first as coff_data (abfd) still does not exist.  It may not even be ever
 143      created as we are just checking the file format of ABFD.  */
 144   memcpy (filehdr_dst->go32stub, filehdr_src->stub, GO32_STUBSIZE);
 145   filehdr_dst->f_flags |= F_GO32STUB;
 146 }
 147
 148 static void
 149 adjust_filehdr_out_pre  (abfd, in, out)
 150      bfd *abfd;
 151      PTR in;
 152      PTR out;
 153 {
 154   struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in;
 155   FILHDR *filehdr_out = (FILHDR *) out;
 156
 157   /* Generate the stub.  */
 158   create_go32_stub (abfd);
 159
 160   /* Copy the stub to the file header.  */
 161   if (coff_data (abfd)->go32stub != NULL)
 162     memcpy (filehdr_out->stub, coff_data (abfd)->go32stub, GO32_STUBSIZE);
 163   else
 164     /* Use the default.  */
 165     memcpy (filehdr_out->stub, stub_bytes, GO32_STUBSIZE);
 166
 167   ADJUST_VAL (filehdr_in->f_symptr, -GO32_STUBSIZE);
 168 }
 169
 170 static void
 171 adjust_filehdr_out_post  (abfd, in, out)
 172      bfd *abfd ATTRIBUTE_UNUSED;
 173      PTR in;
 174      PTR out ATTRIBUTE_UNUSED;
 175 {
 176   struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in;
 177   /* Undo the above change.  */
 178   ADJUST_VAL (filehdr_in->f_symptr, GO32_STUBSIZE);
 179 }
 180
 181 static void
 182 adjust_scnhdr_in_post  (abfd, ext, in)
 183      bfd *abfd ATTRIBUTE_UNUSED;
 184      PTR ext ATTRIBUTE_UNUSED;
 185      PTR in;
 186 {
 187   struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;
 188
 189   ADJUST_VAL (scnhdr_int->s_scnptr, GO32_STUBSIZE);
 190   ADJUST_VAL (scnhdr_int->s_relptr, GO32_STUBSIZE);
 191   ADJUST_VAL (scnhdr_int->s_lnnoptr, GO32_STUBSIZE);
 192 }
 193
 194 static void
 195 adjust_scnhdr_out_pre  (abfd, in, out)
 196      bfd *abfd ATTRIBUTE_UNUSED;
 197      PTR in;
 198      PTR out ATTRIBUTE_UNUSED;
 199 {
 200   struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;
 201
 202   ADJUST_VAL (scnhdr_int->s_scnptr, -GO32_STUBSIZE);
 203   ADJUST_VAL (scnhdr_int->s_relptr, -GO32_STUBSIZE);
 204   ADJUST_VAL (scnhdr_int->s_lnnoptr, -GO32_STUBSIZE);
 205 }
 206
 207 static void
 208 adjust_scnhdr_out_post (abfd, in, out)
 209      bfd *abfd ATTRIBUTE_UNUSED;
 210      PTR in;
 211      PTR out ATTRIBUTE_UNUSED;
 212 {
 213   struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;
 214
 215   ADJUST_VAL (scnhdr_int->s_scnptr, GO32_STUBSIZE);
 216   ADJUST_VAL (scnhdr_int->s_relptr, GO32_STUBSIZE);
 217   ADJUST_VAL (scnhdr_int->s_lnnoptr, GO32_STUBSIZE);
 218 }
 219
 220 static void
 221 adjust_aux_in_post  (abfd, ext1, type, in_class, indx, numaux, in1)
 222      bfd *abfd ATTRIBUTE_UNUSED;
 223      PTR ext1 ATTRIBUTE_UNUSED;
 224      int type;
 225      int in_class;
 226      int indx ATTRIBUTE_UNUSED;
 227      int numaux ATTRIBUTE_UNUSED;
 228      PTR in1;
 229 {
 230   union internal_auxent *in = (union internal_auxent *) in1;
 231
 232   if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type)
 233       || ISTAG (in_class))
 234     {
 235       ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE);
 236     }
 237 }
 238
 239 static void
 240 adjust_aux_out_pre  (abfd, inp, type, in_class, indx, numaux, extp)
 241      bfd *abfd ATTRIBUTE_UNUSED;
 242      PTR inp;
 243      int type;
 244      int in_class;
 245      int indx ATTRIBUTE_UNUSED;
 246      int numaux ATTRIBUTE_UNUSED;
 247      PTR extp ATTRIBUTE_UNUSED;
 248 {
 249   union internal_auxent *in = (union internal_auxent *) inp;
 250
 251   if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type)
 252       || ISTAG (in_class))
 253     {
 254       ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, -GO32_STUBSIZE);
 255     }
 256 }
 257
 258 static void
 259 adjust_aux_out_post (abfd, inp, type, in_class, indx, numaux, extp)
 260      bfd *abfd ATTRIBUTE_UNUSED;
 261      PTR inp;
 262      int type;
 263      int in_class;
 264      int indx ATTRIBUTE_UNUSED;
 265      int numaux ATTRIBUTE_UNUSED;
 266      PTR extp ATTRIBUTE_UNUSED;
 267 {
 268   union internal_auxent *in = (union internal_auxent *) inp;
 269
 270   if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type)
 271       || ISTAG (in_class))
 272     {
 273       ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE);
 274     }
 275 }
 276
 277 /* That's the function, which creates the stub. There are
 278    different cases from where the stub is taken.
 279    At first the environment variable $(GO32STUB) is checked and then
 280    $(STUB) if it was not set.
 281    If it exists and points to a valid stub the stub is taken from
 282    that file. This file can be also a whole executable file, because
 283    the stub is computed from the exe information at the start of that
 284    file.
 285
 286    If there was any error, the standard stub (compiled in this file)
 287    is taken.  */
 288
 289 static void
 290 create_go32_stub (abfd)
 291      bfd *abfd;
 292 {
 293   /* Do it only once.  */
 294   if (coff_data (abfd)->go32stub == NULL)
 295     {
 296       char *stub;
 297       struct stat st;
 298       int f;
 299       unsigned char header[10];
 300       char magic[8];
 301       unsigned long coff_start;
 302       long exe_start;
 303
 304       /* Check at first the environment variable $(GO32STUB).  */
 305       stub = getenv ("GO32STUB");
 306       /* Now check the environment variable $(STUB).  */
 307       if (stub == NULL)
 308         stub = getenv ("STUB");
 309       if (stub == NULL)
 310         goto stub_end;
 311       if (stat (stub, &st) != 0)
 312         goto stub_end;
 313 #ifdef O_BINARY
 314       f = open (stub, O_RDONLY | O_BINARY);
 315 #else
 316       f = open (stub, O_RDONLY);
 317 #endif
 318       if (f < 0)
 319         goto stub_end;
 320       if (read (f, &header, sizeof (header)) < 0)
 321         {
 322           close (f);
 323           goto stub_end;
 324         }
 325       if (_H (0) != 0x5a4d)     /* It is not an exe file.  */
 326         {
 327           close (f);
 328           goto stub_end;
 329         }
 330       /* Compute the size of the stub (it is every thing up
 331          to the beginning of the coff image).  */
 332       coff_start = (long) _H (2) * 512L;
 333       if (_H (1))
 334         coff_start += (long) _H (1) - 512L;
 335
 336       /* Currently there is only a fixed stub size of 2048 bytes
 337          supported.  */
 338       if (coff_start != 2048)
 339         {
 340           close (f);
 341           goto stub_end;
 342         }
 343       exe_start = _H (4) * 16;
 344       if ((long) lseek (f, exe_start, SEEK_SET) != exe_start)
 345         {
 346           close (f);
 347           goto stub_end;
 348         }
 349       if (read (f, &magic, 8) != 8)
 350         {
 351           close (f);
 352           goto stub_end;
 353         }
 354       if (! CONST_STRNEQ (magic, "go32stub"))
 355         {
 356           close (f);
 357           goto stub_end;
 358         }
 359       /* Now we found a correct stub (hopefully).  */
 360       coff_data (abfd)->go32stub = bfd_alloc (abfd, (bfd_size_type) coff_start);
 361       if (coff_data (abfd)->go32stub == NULL)
 362         {
 363           close (f);
 364           return;
 365         }
 366       lseek (f, 0L, SEEK_SET);
 367       if ((unsigned long) read (f, coff_data (abfd)->go32stub, coff_start)
 368           != coff_start)
 369         {
 370           bfd_release (abfd, coff_data (abfd)->go32stub);
 371           coff_data (abfd)->go32stub = NULL;
 372         }
 373       close (f);
 374     }
 375 stub_end:
 376   /* There was something wrong above, so use now the standard builtin
 377      stub.  */
 378   if (coff_data (abfd)->go32stub == NULL)
 379     {
 380       coff_data (abfd)->go32stub
 381         = bfd_alloc (abfd, (bfd_size_type) GO32_STUBSIZE);
 382       if (coff_data (abfd)->go32stub == NULL)
 383         return;
 384       memcpy (coff_data (abfd)->go32stub, stub_bytes, GO32_STUBSIZE);
 385     }
 386 }
 387
 388 /* If ibfd was a stubbed coff image, copy the stub from that bfd
 389    to the new obfd.  */
 390
 391 static bfd_boolean
 392 go32_stubbed_coff_bfd_copy_private_bfd_data  (ibfd, obfd)
 393      bfd *ibfd;
 394      bfd *obfd;
 395 {
 396   /* Check if both are the same targets.  */
 397   if (ibfd->xvec != obfd->xvec)
 398     return TRUE;
 399
 400   /* Check if we have a source stub.  */
 401   if (coff_data (ibfd)->go32stub == NULL)
 402     return TRUE;
 403
 404   /* As adjust_filehdr_out_pre may get called only after this function,
 405      optionally allocate the output stub.  */
 406   if (coff_data (obfd)->go32stub == NULL)
 407     coff_data (obfd)->go32stub = bfd_alloc (obfd,
 408                                           (bfd_size_type) GO32_STUBSIZE);
 409
 410   /* Now copy the stub.  */
 411   if (coff_data (obfd)->go32stub != NULL)
 412     memcpy (coff_data (obfd)->go32stub, coff_data (ibfd)->go32stub,
 413             GO32_STUBSIZE);
 414
 415   return TRUE;
 416 }