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 Free Software Foundation, Inc.
   3    Written by Robert Hoehne.
   4
   5    This file is part of BFD, the Binary File Descriptor library.
   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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 /* This file handles now also stubbed coff images. The stub is a small
  22    DOS executable program before the coff image to load it in memory
  23    and execute it. This is needed, because DOS cannot run coff files.
  24
  25    All the functions below are called by the corresponding functions
  26    from coffswap.h.
  27    The only thing what they do is to adjust the information stored in
  28    the COFF file which are offset into the file.
  29    This is needed, because DJGPP uses a very special way to load and run
  30    the coff image. It loads the image in memory and assumes then, that the
  31    image had no stub by using the filepointers as pointers in the coff
  32    image and NOT in the file.
  33
  34    To be compatible with any existing executables I have fixed this
  35    here and NOT in the DJGPP startup code.
  36  */
  37
  38 #define TARGET_SYM              go32stubbedcoff_vec
  39 #define TARGET_NAME             "coff-go32-exe"
  40 #define TARGET_UNDERSCORE       '_'
  41 #define COFF_GO32_EXE
  42 #define COFF_LONG_SECTION_NAMES
  43 #define COFF_SUPPORT_GNU_LINKONCE
  44 #define COFF_LONG_FILENAMES
  45
  46 #define COFF_SECTION_ALIGNMENT_ENTRIES \
  47 { COFF_SECTION_NAME_EXACT_MATCH (".data"), \
  48   COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 4 }, \
  49 { COFF_SECTION_NAME_EXACT_MATCH (".text"), \
  50   COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 4 }, \
  51 { COFF_SECTION_NAME_PARTIAL_MATCH (".debug"), \
  52   COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 0 }, \
  53 { COFF_SECTION_NAME_PARTIAL_MATCH (".gnu.linkonce.wi"), \
  54   COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 0 }
  55
  56 #include "bfd.h"
  57
  58 /* At first the prototypes */
  59
  60 static void
  61 adjust_filehdr_in_post PARAMS ((bfd * abfd, PTR src, PTR dst));
  62 static void
  63 adjust_filehdr_out_pre PARAMS ((bfd * abfd, PTR in, PTR out));
  64 static void
  65 adjust_filehdr_out_post PARAMS ((bfd * abfd, PTR in, PTR out));
  66
  67 static void
  68 adjust_scnhdr_in_post PARAMS ((bfd * abfd, PTR ext, PTR in));
  69 static void
  70 adjust_scnhdr_out_pre PARAMS ((bfd * abfd, PTR in, PTR out));
  71 static void
  72 adjust_scnhdr_out_post PARAMS ((bfd * abfd, PTR in, PTR out));
  73
  74 static void
  75 adjust_aux_in_post PARAMS ((bfd * abfd, PTR ext1, int type, int class, int indx,
  76                             int numaux, PTR in1));
  77 static void
  78 adjust_aux_out_pre PARAMS ((bfd * abfd, PTR inp, int type, int class, int indx,
  79                             int numaux, PTR extp));
  80 static void
  81 adjust_aux_out_post PARAMS ((bfd * abfd, PTR inp, int type, int class, int indx,
  82                              int numaux, PTR extp));
  83
  84 static void
  85 create_go32_stub PARAMS ((bfd * abfd));
  86
  87 /*
  88    All that ..._PRE and ...POST functions are called from the corresponding
  89    coff_swap... functions. The ...PRE functions are called at the beginning
  90    of the function and the ...POST functions at the end of the swap routines.
  91  */
  92
  93 #define COFF_ADJUST_FILEHDR_IN_POST adjust_filehdr_in_post
  94 #define COFF_ADJUST_FILEHDR_OUT_PRE adjust_filehdr_out_pre
  95 #define COFF_ADJUST_FILEHDR_OUT_POST adjust_filehdr_out_post
  96
  97 #define COFF_ADJUST_SCNHDR_IN_POST adjust_scnhdr_in_post
  98 #define COFF_ADJUST_SCNHDR_OUT_PRE adjust_scnhdr_out_pre
  99 #define COFF_ADJUST_SCNHDR_OUT_POST adjust_scnhdr_out_post
 100
 101 #define COFF_ADJUST_AUX_IN_POST adjust_aux_in_post
 102 #define COFF_ADJUST_AUX_OUT_PRE adjust_aux_out_pre
 103 #define COFF_ADJUST_AUX_OUT_POST adjust_aux_out_post
 104
 105 static boolean
 106   go32_stubbed_coff_bfd_copy_private_bfd_data PARAMS ((bfd * ibfd, bfd * obfd));
 107
 108 #define coff_bfd_copy_private_bfd_data go32_stubbed_coff_bfd_copy_private_bfd_data
 109
 110 #include "coff-i386.c"
 111
 112 /* I hold in the usrdata the stub */
 113 #define bfd_coff_go32stub bfd_usrdata
 114
 115 /* This macro is used, because I cannot assume the endianess of the
 116    host system */
 117 #define _H(index) (H_GET_16 (abfd, (header+index*2)))
 118
 119 /* These bytes are a 2048-byte DOS executable, which loads the COFF
 120    image into memory and then runs it. It is called 'stub' */
 121
 122 static unsigned char stub_bytes[STUBSIZE] =
 123 {
 124 #include "go32stub.h"
 125 };
 126
 127 /*
 128    I have not commented each swap function below, because the
 129    technique is in any function the same. For the ...in function,
 130    all the pointers are adjusted by adding STUBSIZE and for the
 131    ...out function, it is subtracted first and after calling the
 132    standard swap function it is reset to the old value */
 133
 134 /* This macro is used for adjusting the filepointers, which
 135    is done only, if the pointer is nonzero */
 136
 137 #define ADJUST_VAL(val,diff) \
 138   if (val != 0) val += diff
 139
 140 static void
 141 adjust_filehdr_in_post  (abfd, src, dst)
 142      bfd *abfd;
 143      PTR src;
 144      PTR dst;
 145 {
 146   FILHDR *filehdr_src = (FILHDR *) src;
 147   struct internal_filehdr *filehdr_dst = (struct internal_filehdr *) dst;
 148
 149   ADJUST_VAL (filehdr_dst->f_symptr, STUBSIZE);
 150
 151   /* Save now the stub to be used later */
 152   bfd_coff_go32stub (abfd) = (PTR) bfd_alloc (abfd, (bfd_size_type) STUBSIZE);
 153
 154   /* Since this function returns no status, I do not set here
 155      any bfd_error_...
 156      That means, before the use of bfd_coff_go32stub (), this value
 157      should be checked if it is != NULL */
 158   if (bfd_coff_go32stub (abfd) == NULL)
 159     return;
 160   memcpy (bfd_coff_go32stub (abfd), filehdr_src->stub, STUBSIZE);
 161 }
 162
 163 static void
 164 adjust_filehdr_out_pre  (abfd, in, out)
 165      bfd *abfd;
 166      PTR in;
 167      PTR out;
 168 {
 169   struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in;
 170   FILHDR *filehdr_out = (FILHDR *) out;
 171
 172   /* Generate the stub */
 173   create_go32_stub (abfd);
 174
 175   /* Copy the stub to the file header */
 176   if (bfd_coff_go32stub (abfd) != NULL)
 177     memcpy (filehdr_out->stub, bfd_coff_go32stub (abfd), STUBSIZE);
 178   else
 179     /* use the default */
 180     memcpy (filehdr_out->stub, stub_bytes, STUBSIZE);
 181
 182   ADJUST_VAL (filehdr_in->f_symptr, -STUBSIZE);
 183 }
 184
 185 static void
 186 adjust_filehdr_out_post  (abfd, in, out)
 187      bfd *abfd ATTRIBUTE_UNUSED;
 188      PTR in;
 189      PTR out ATTRIBUTE_UNUSED;
 190 {
 191   struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in;
 192   /* undo the above change */
 193   ADJUST_VAL (filehdr_in->f_symptr, STUBSIZE);
 194 }
 195
 196 static void
 197 adjust_scnhdr_in_post  (abfd, ext, in)
 198      bfd *abfd ATTRIBUTE_UNUSED;
 199      PTR ext ATTRIBUTE_UNUSED;
 200      PTR in;
 201 {
 202   struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;
 203
 204   ADJUST_VAL (scnhdr_int->s_scnptr, STUBSIZE);
 205   ADJUST_VAL (scnhdr_int->s_relptr, STUBSIZE);
 206   ADJUST_VAL (scnhdr_int->s_lnnoptr, STUBSIZE);
 207 }
 208
 209 static void
 210 adjust_scnhdr_out_pre  (abfd, in, out)
 211      bfd *abfd ATTRIBUTE_UNUSED;
 212      PTR in;
 213      PTR out ATTRIBUTE_UNUSED;
 214 {
 215   struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;
 216
 217   ADJUST_VAL (scnhdr_int->s_scnptr, -STUBSIZE);
 218   ADJUST_VAL (scnhdr_int->s_relptr, -STUBSIZE);
 219   ADJUST_VAL (scnhdr_int->s_lnnoptr, -STUBSIZE);
 220 }
 221
 222 static void
 223 adjust_scnhdr_out_post (abfd, in, out)
 224      bfd *abfd ATTRIBUTE_UNUSED;
 225      PTR in;
 226      PTR out ATTRIBUTE_UNUSED;
 227 {
 228   struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;
 229
 230   ADJUST_VAL (scnhdr_int->s_scnptr, STUBSIZE);
 231   ADJUST_VAL (scnhdr_int->s_relptr, STUBSIZE);
 232   ADJUST_VAL (scnhdr_int->s_lnnoptr, STUBSIZE);
 233 }
 234
 235 static void
 236 adjust_aux_in_post  (abfd, ext1, type, class, indx, numaux, in1)
 237      bfd *abfd ATTRIBUTE_UNUSED;
 238      PTR ext1 ATTRIBUTE_UNUSED;
 239      int type;
 240      int class;
 241      int indx ATTRIBUTE_UNUSED;
 242      int numaux ATTRIBUTE_UNUSED;
 243      PTR in1;
 244 {
 245   union internal_auxent *in = (union internal_auxent *) in1;
 246
 247   if (class == C_BLOCK || class == C_FCN || ISFCN (type) || ISTAG (class))
 248     {
 249       ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, STUBSIZE);
 250     }
 251 }
 252
 253 static void
 254 adjust_aux_out_pre  (abfd, inp, type, class, indx, numaux, extp)
 255      bfd *abfd ATTRIBUTE_UNUSED;
 256      PTR inp;
 257      int type;
 258      int class;
 259      int indx ATTRIBUTE_UNUSED;
 260      int numaux ATTRIBUTE_UNUSED;
 261      PTR extp ATTRIBUTE_UNUSED;
 262 {
 263   union internal_auxent *in = (union internal_auxent *) inp;
 264
 265   if (class == C_BLOCK || class == C_FCN || ISFCN (type) || ISTAG (class))
 266     {
 267       ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, -STUBSIZE);
 268     }
 269 }
 270
 271 static void
 272 adjust_aux_out_post (abfd, inp, type, class, indx, numaux, extp)
 273      bfd *abfd ATTRIBUTE_UNUSED;
 274      PTR inp;
 275      int type;
 276      int class;
 277      int indx ATTRIBUTE_UNUSED;
 278      int numaux ATTRIBUTE_UNUSED;
 279      PTR extp ATTRIBUTE_UNUSED;
 280 {
 281   union internal_auxent *in = (union internal_auxent *) inp;
 282
 283   if (class == C_BLOCK || class == C_FCN || ISFCN (type) || ISTAG (class))
 284     {
 285       ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, STUBSIZE);
 286     }
 287 }
 288
 289 /*
 290    That's the function, which creates the stub. There are
 291    different cases from where the stub is taken.
 292    At first the environment variable $(GO32STUB) is checked and then
 293    $(STUB) if it was not set.
 294    If it exists and points to a valid stub the stub is taken from
 295    that file. This file can be also a whole executable file, because
 296    the stub is computed from the exe information at the start of that
 297    file.
 298
 299    If there was any error, the standard stub (compiled in this file)
 300    is taken.
 301  */
 302
 303 static void
 304 create_go32_stub (abfd)
 305      bfd *abfd;
 306 {
 307   /* Do it only once */
 308   if (bfd_coff_go32stub (abfd) == NULL)
 309     {
 310       char *stub;
 311       struct stat st;
 312       int f;
 313       unsigned char header[10];
 314       char magic[8];
 315       unsigned long coff_start;
 316       long exe_start;
 317
 318       /* Check at first the environment variable $(GO32STUB) */
 319       stub = getenv ("GO32STUB");
 320       /* Now check the environment variable $(STUB) */
 321       if (stub == NULL)
 322         stub = getenv ("STUB");
 323       if (stub == NULL)
 324         goto stub_end;
 325       if (stat (stub, &st) != 0)
 326         goto stub_end;
 327 #ifdef O_BINARY
 328       f = open (stub, O_RDONLY | O_BINARY);
 329 #else
 330       f = open (stub, O_RDONLY);
 331 #endif
 332       if (f < 0)
 333         goto stub_end;
 334       if (read (f, &header, sizeof (header)) < 0)
 335         {
 336           close (f);
 337           goto stub_end;
 338         }
 339       if (_H (0) != 0x5a4d)     /* it is not an exe file */
 340         {
 341           close (f);
 342           goto stub_end;
 343         }
 344       /* Compute the size of the stub (it is every thing up
 345          to the beginning of the coff image) */
 346       coff_start = (long) _H (2) * 512L;
 347       if (_H (1))
 348         coff_start += (long) _H (1) - 512L;
 349
 350       /* Currently there is only a fixed stub size of 2048 bytes
 351          supported */
 352       if (coff_start != 2048)
 353         {
 354           close (f);
 355           goto stub_end;
 356         }
 357       exe_start = _H (4) * 16;
 358       if ((long) lseek (f, exe_start, SEEK_SET) != exe_start)
 359         {
 360           close (f);
 361           goto stub_end;
 362         }
 363       if (read (f, &magic, 8) != 8)
 364         {
 365           close (f);
 366           goto stub_end;
 367         }
 368       if (memcmp (magic, "go32stub", 8) != 0)
 369         {
 370           close (f);
 371           goto stub_end;
 372         }
 373       /* Now we found a correct stub (hopefully) */
 374       bfd_coff_go32stub (abfd)
 375         = (PTR) bfd_alloc (abfd, (bfd_size_type) coff_start);
 376       if (bfd_coff_go32stub (abfd) == NULL)
 377         {
 378           close (f);
 379           return;
 380         }
 381       lseek (f, 0L, SEEK_SET);
 382       if ((unsigned long) read (f, bfd_coff_go32stub (abfd), coff_start)
 383           != coff_start)
 384         {
 385           bfd_release (abfd, bfd_coff_go32stub (abfd));
 386           bfd_coff_go32stub (abfd) = NULL;
 387         }
 388       close (f);
 389     }
 390 stub_end:
 391   /* There was something wrong above, so use now the standard builtin
 392      stub */
 393   if (bfd_coff_go32stub (abfd) == NULL)
 394     {
 395       bfd_coff_go32stub (abfd)
 396         = (PTR) bfd_alloc (abfd, (bfd_size_type) STUBSIZE);
 397       if (bfd_coff_go32stub (abfd) == NULL)
 398         {
 399           return;
 400         }
 401
 402       memcpy (bfd_coff_go32stub (abfd), stub_bytes, STUBSIZE);
 403     }
 404 }
 405
 406 /* If ibfd was a stubbed coff image, copy the stub from that bfd
 407    to the new obfd.
 408  */
 409
 410 static boolean
 411 go32_stubbed_coff_bfd_copy_private_bfd_data  (ibfd, obfd)
 412      bfd *ibfd;
 413      bfd *obfd;
 414 {
 415   /* check if both are the same targets */
 416   if (ibfd->xvec != obfd->xvec)
 417     return true;
 418
 419   /* check if both have a valid stub */
 420   if (bfd_coff_go32stub (ibfd) == NULL
 421       || bfd_coff_go32stub (obfd) == NULL)
 422     return true;
 423
 424   /* Now copy the stub */
 425   memcpy (bfd_coff_go32stub (obfd), bfd_coff_go32stub (ibfd), STUBSIZE);
 426
 427   return true;
 428 }