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, 2006, 2007
   3    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 endianess 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, class, indx, numaux, in1)
 222      bfd *abfd ATTRIBUTE_UNUSED;
 223      PTR ext1 ATTRIBUTE_UNUSED;
 224      int type;
 225      int 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 (class == C_BLOCK || class == C_FCN || ISFCN (type) || ISTAG (class))
 233     {
 234       ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE);
 235     }
 236 }
 237
 238 static void
 239 adjust_aux_out_pre  (abfd, inp, type, class, indx, numaux, extp)
 240      bfd *abfd ATTRIBUTE_UNUSED;
 241      PTR inp;
 242      int type;
 243      int class;
 244      int indx ATTRIBUTE_UNUSED;
 245      int numaux ATTRIBUTE_UNUSED;
 246      PTR extp ATTRIBUTE_UNUSED;
 247 {
 248   union internal_auxent *in = (union internal_auxent *) inp;
 249
 250   if (class == C_BLOCK || class == C_FCN || ISFCN (type) || ISTAG (class))
 251     {
 252       ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, -GO32_STUBSIZE);
 253     }
 254 }
 255
 256 static void
 257 adjust_aux_out_post (abfd, inp, type, class, indx, numaux, extp)
 258      bfd *abfd ATTRIBUTE_UNUSED;
 259      PTR inp;
 260      int type;
 261      int class;
 262      int indx ATTRIBUTE_UNUSED;
 263      int numaux ATTRIBUTE_UNUSED;
 264      PTR extp ATTRIBUTE_UNUSED;
 265 {
 266   union internal_auxent *in = (union internal_auxent *) inp;
 267
 268   if (class == C_BLOCK || class == C_FCN || ISFCN (type) || ISTAG (class))
 269     {
 270       ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE);
 271     }
 272 }
 273
 274 /* That's the function, which creates the stub. There are
 275    different cases from where the stub is taken.
 276    At first the environment variable $(GO32STUB) is checked and then
 277    $(STUB) if it was not set.
 278    If it exists and points to a valid stub the stub is taken from
 279    that file. This file can be also a whole executable file, because
 280    the stub is computed from the exe information at the start of that
 281    file.
 282
 283    If there was any error, the standard stub (compiled in this file)
 284    is taken.  */
 285
 286 static void
 287 create_go32_stub (abfd)
 288      bfd *abfd;
 289 {
 290   /* Do it only once.  */
 291   if (coff_data (abfd)->go32stub == NULL)
 292     {
 293       char *stub;
 294       struct stat st;
 295       int f;
 296       unsigned char header[10];
 297       char magic[8];
 298       unsigned long coff_start;
 299       long exe_start;
 300
 301       /* Check at first the environment variable $(GO32STUB).  */
 302       stub = getenv ("GO32STUB");
 303       /* Now check the environment variable $(STUB).  */
 304       if (stub == NULL)
 305         stub = getenv ("STUB");
 306       if (stub == NULL)
 307         goto stub_end;
 308       if (stat (stub, &st) != 0)
 309         goto stub_end;
 310 #ifdef O_BINARY
 311       f = open (stub, O_RDONLY | O_BINARY);
 312 #else
 313       f = open (stub, O_RDONLY);
 314 #endif
 315       if (f < 0)
 316         goto stub_end;
 317       if (read (f, &header, sizeof (header)) < 0)
 318         {
 319           close (f);
 320           goto stub_end;
 321         }
 322       if (_H (0) != 0x5a4d)     /* It is not an exe file.  */
 323         {
 324           close (f);
 325           goto stub_end;
 326         }
 327       /* Compute the size of the stub (it is every thing up
 328          to the beginning of the coff image).  */
 329       coff_start = (long) _H (2) * 512L;
 330       if (_H (1))
 331         coff_start += (long) _H (1) - 512L;
 332
 333       /* Currently there is only a fixed stub size of 2048 bytes
 334          supported.  */
 335       if (coff_start != 2048)
 336         {
 337           close (f);
 338           goto stub_end;
 339         }
 340       exe_start = _H (4) * 16;
 341       if ((long) lseek (f, exe_start, SEEK_SET) != exe_start)
 342         {
 343           close (f);
 344           goto stub_end;
 345         }
 346       if (read (f, &magic, 8) != 8)
 347         {
 348           close (f);
 349           goto stub_end;
 350         }
 351       if (! CONST_STRNEQ (magic, "go32stub"))
 352         {
 353           close (f);
 354           goto stub_end;
 355         }
 356       /* Now we found a correct stub (hopefully).  */
 357       coff_data (abfd)->go32stub = bfd_alloc (abfd, (bfd_size_type) coff_start);
 358       if (coff_data (abfd)->go32stub == NULL)
 359         {
 360           close (f);
 361           return;
 362         }
 363       lseek (f, 0L, SEEK_SET);
 364       if ((unsigned long) read (f, coff_data (abfd)->go32stub, coff_start)
 365           != coff_start)
 366         {
 367           bfd_release (abfd, coff_data (abfd)->go32stub);
 368           coff_data (abfd)->go32stub = NULL;
 369         }
 370       close (f);
 371     }
 372 stub_end:
 373   /* There was something wrong above, so use now the standard builtin
 374      stub.  */
 375   if (coff_data (abfd)->go32stub == NULL)
 376     {
 377       coff_data (abfd)->go32stub
 378         = bfd_alloc (abfd, (bfd_size_type) GO32_STUBSIZE);
 379       if (coff_data (abfd)->go32stub == NULL)
 380         return;
 381       memcpy (coff_data (abfd)->go32stub, stub_bytes, GO32_STUBSIZE);
 382     }
 383 }
 384
 385 /* If ibfd was a stubbed coff image, copy the stub from that bfd
 386    to the new obfd.  */
 387
 388 static bfd_boolean
 389 go32_stubbed_coff_bfd_copy_private_bfd_data  (ibfd, obfd)
 390      bfd *ibfd;
 391      bfd *obfd;
 392 {
 393   /* Check if both are the same targets.  */
 394   if (ibfd->xvec != obfd->xvec)
 395     return TRUE;
 396
 397   /* Check if we have a source stub.  */
 398   if (coff_data (ibfd)->go32stub == NULL)
 399     return TRUE;
 400
 401   /* As adjust_filehdr_out_pre may get called only after this function,
 402      optionally allocate the output stub.  */
 403   if (coff_data (obfd)->go32stub == NULL)
 404     coff_data (obfd)->go32stub = bfd_alloc (obfd,
 405                                           (bfd_size_type) GO32_STUBSIZE);
 406
 407   /* Now copy the stub.  */
 408   if (coff_data (obfd)->go32stub != NULL)
 409     memcpy (coff_data (obfd)->go32stub, coff_data (ibfd)->go32stub,
 410             GO32_STUBSIZE);
 411
 412   return TRUE;
 413 }