| 1 | /* BFD back-end for Intel 386 COFF files (DJGPP variant with a stub). |
| 2 | Copyright (C) 1997-2017 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 3 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., 51 Franklin Street - Fifth Floor, Boston, |
| 20 | MA 02110-1301, USA. */ |
| 21 | |
| 22 | /* This file handles now also stubbed coff images. The stub is a small |
| 23 | DOS executable program before the coff image to load it in memory |
| 24 | and execute it. This is needed, because DOS cannot run coff files. |
| 25 | |
| 26 | All the functions below are called by the corresponding functions |
| 27 | from coffswap.h. |
| 28 | The only thing what they do is to adjust the information stored in |
| 29 | the COFF file which are offset into the file. |
| 30 | This is needed, because DJGPP uses a very special way to load and run |
| 31 | the coff image. It loads the image in memory and assumes then, that the |
| 32 | image had no stub by using the filepointers as pointers in the coff |
| 33 | image and NOT in the file. |
| 34 | |
| 35 | To be compatible with any existing executables I have fixed this |
| 36 | here and NOT in the DJGPP startup code. */ |
| 37 | |
| 38 | #define TARGET_SYM i386_coff_go32stubbed_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 "sysdep.h" |
| 57 | #include "bfd.h" |
| 58 | |
| 59 | /* All that ..._PRE and ...POST functions are called from the corresponding |
| 60 | coff_swap... functions. The ...PRE functions are called at the beginning |
| 61 | of the function and the ...POST functions at the end of the swap routines. */ |
| 62 | |
| 63 | static void |
| 64 | adjust_filehdr_in_post (bfd *, void *, void *); |
| 65 | static void |
| 66 | adjust_filehdr_out_pre (bfd *, void *, void *); |
| 67 | static void |
| 68 | adjust_filehdr_out_post (bfd *, void *, void *); |
| 69 | static void |
| 70 | adjust_scnhdr_in_post (bfd *, void *, void *); |
| 71 | static void |
| 72 | adjust_scnhdr_out_pre (bfd *, void *, void *); |
| 73 | static void |
| 74 | adjust_scnhdr_out_post (bfd *, void *, void *); |
| 75 | static void |
| 76 | adjust_aux_in_post (bfd *, void *, int, int, int, int, void *); |
| 77 | static void |
| 78 | adjust_aux_out_pre (bfd *, void *, int, int, int, int, void *); |
| 79 | static void |
| 80 | adjust_aux_out_post (bfd *, void *, int, int, int, int, void *); |
| 81 | static void |
| 82 | create_go32_stub (bfd *); |
| 83 | |
| 84 | #define COFF_ADJUST_FILEHDR_IN_POST adjust_filehdr_in_post |
| 85 | #define COFF_ADJUST_FILEHDR_OUT_PRE adjust_filehdr_out_pre |
| 86 | #define COFF_ADJUST_FILEHDR_OUT_POST adjust_filehdr_out_post |
| 87 | |
| 88 | #define COFF_ADJUST_SCNHDR_IN_POST adjust_scnhdr_in_post |
| 89 | #define COFF_ADJUST_SCNHDR_OUT_PRE adjust_scnhdr_out_pre |
| 90 | #define COFF_ADJUST_SCNHDR_OUT_POST adjust_scnhdr_out_post |
| 91 | |
| 92 | #define COFF_ADJUST_AUX_IN_POST adjust_aux_in_post |
| 93 | #define COFF_ADJUST_AUX_OUT_PRE adjust_aux_out_pre |
| 94 | #define COFF_ADJUST_AUX_OUT_POST adjust_aux_out_post |
| 95 | |
| 96 | static const bfd_target *go32_check_format (bfd *); |
| 97 | |
| 98 | #define COFF_CHECK_FORMAT go32_check_format |
| 99 | |
| 100 | static bfd_boolean |
| 101 | go32_stubbed_coff_bfd_copy_private_bfd_data (bfd *, bfd *); |
| 102 | |
| 103 | #define coff_bfd_copy_private_bfd_data go32_stubbed_coff_bfd_copy_private_bfd_data |
| 104 | |
| 105 | #include "coff-i386.c" |
| 106 | |
| 107 | /* This macro is used, because I cannot assume the endianness of the |
| 108 | host system. */ |
| 109 | #define _H(index) (H_GET_16 (abfd, (header + index * 2))) |
| 110 | |
| 111 | /* These bytes are a 2048-byte DOS executable, which loads the COFF |
| 112 | image into memory and then runs it. It is called 'stub'. */ |
| 113 | |
| 114 | static const unsigned char stub_bytes[GO32_STUBSIZE] = |
| 115 | { |
| 116 | #include "go32stub.h" |
| 117 | }; |
| 118 | |
| 119 | /* |
| 120 | I have not commented each swap function below, because the |
| 121 | technique is in any function the same. For the ...in function, |
| 122 | all the pointers are adjusted by adding GO32_STUBSIZE and for the |
| 123 | ...out function, it is subtracted first and after calling the |
| 124 | standard swap function it is reset to the old value. */ |
| 125 | |
| 126 | /* This macro is used for adjusting the filepointers, which |
| 127 | is done only, if the pointer is nonzero. */ |
| 128 | |
| 129 | #define ADJUST_VAL(val,diff) \ |
| 130 | if (val != 0) val += diff |
| 131 | |
| 132 | static void |
| 133 | adjust_filehdr_in_post (bfd * abfd ATTRIBUTE_UNUSED, |
| 134 | void * src, |
| 135 | void * dst) |
| 136 | { |
| 137 | FILHDR *filehdr_src = (FILHDR *) src; |
| 138 | struct internal_filehdr *filehdr_dst = (struct internal_filehdr *) dst; |
| 139 | |
| 140 | ADJUST_VAL (filehdr_dst->f_symptr, GO32_STUBSIZE); |
| 141 | |
| 142 | /* Save now the stub to be used later. Put the stub data to FILEHDR_DST |
| 143 | first as coff_data (abfd) still does not exist. It may not even be ever |
| 144 | created as we are just checking the file format of ABFD. */ |
| 145 | memcpy (filehdr_dst->go32stub, filehdr_src->stub, GO32_STUBSIZE); |
| 146 | filehdr_dst->f_flags |= F_GO32STUB; |
| 147 | } |
| 148 | |
| 149 | static void |
| 150 | adjust_filehdr_out_pre (bfd * abfd, void * in, void * out) |
| 151 | { |
| 152 | struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in; |
| 153 | FILHDR *filehdr_out = (FILHDR *) out; |
| 154 | |
| 155 | /* Generate the stub. */ |
| 156 | create_go32_stub (abfd); |
| 157 | |
| 158 | /* Copy the stub to the file header. */ |
| 159 | if (coff_data (abfd)->go32stub != NULL) |
| 160 | memcpy (filehdr_out->stub, coff_data (abfd)->go32stub, GO32_STUBSIZE); |
| 161 | else |
| 162 | /* Use the default. */ |
| 163 | memcpy (filehdr_out->stub, stub_bytes, GO32_STUBSIZE); |
| 164 | |
| 165 | ADJUST_VAL (filehdr_in->f_symptr, -GO32_STUBSIZE); |
| 166 | } |
| 167 | |
| 168 | static void |
| 169 | adjust_filehdr_out_post (bfd * abfd ATTRIBUTE_UNUSED, |
| 170 | void * in, |
| 171 | void * out ATTRIBUTE_UNUSED) |
| 172 | { |
| 173 | struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in; |
| 174 | /* Undo the above change. */ |
| 175 | ADJUST_VAL (filehdr_in->f_symptr, GO32_STUBSIZE); |
| 176 | } |
| 177 | |
| 178 | static void |
| 179 | adjust_scnhdr_in_post (bfd * abfd ATTRIBUTE_UNUSED, |
| 180 | void * ext ATTRIBUTE_UNUSED, |
| 181 | void * in) |
| 182 | { |
| 183 | struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in; |
| 184 | |
| 185 | ADJUST_VAL (scnhdr_int->s_scnptr, GO32_STUBSIZE); |
| 186 | ADJUST_VAL (scnhdr_int->s_relptr, GO32_STUBSIZE); |
| 187 | ADJUST_VAL (scnhdr_int->s_lnnoptr, GO32_STUBSIZE); |
| 188 | } |
| 189 | |
| 190 | static void |
| 191 | adjust_scnhdr_out_pre (bfd * abfd ATTRIBUTE_UNUSED, |
| 192 | void * in, |
| 193 | void * out ATTRIBUTE_UNUSED) |
| 194 | { |
| 195 | struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in; |
| 196 | |
| 197 | ADJUST_VAL (scnhdr_int->s_scnptr, -GO32_STUBSIZE); |
| 198 | ADJUST_VAL (scnhdr_int->s_relptr, -GO32_STUBSIZE); |
| 199 | ADJUST_VAL (scnhdr_int->s_lnnoptr, -GO32_STUBSIZE); |
| 200 | } |
| 201 | |
| 202 | static void |
| 203 | adjust_scnhdr_out_post (bfd * abfd ATTRIBUTE_UNUSED, |
| 204 | void * in, |
| 205 | void * out ATTRIBUTE_UNUSED) |
| 206 | { |
| 207 | struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in; |
| 208 | |
| 209 | ADJUST_VAL (scnhdr_int->s_scnptr, GO32_STUBSIZE); |
| 210 | ADJUST_VAL (scnhdr_int->s_relptr, GO32_STUBSIZE); |
| 211 | ADJUST_VAL (scnhdr_int->s_lnnoptr, GO32_STUBSIZE); |
| 212 | } |
| 213 | |
| 214 | static void |
| 215 | adjust_aux_in_post (bfd * abfd ATTRIBUTE_UNUSED, |
| 216 | void * ext1 ATTRIBUTE_UNUSED, |
| 217 | int type, |
| 218 | int in_class, |
| 219 | int indx ATTRIBUTE_UNUSED, |
| 220 | int numaux ATTRIBUTE_UNUSED, |
| 221 | void * in1) |
| 222 | { |
| 223 | union internal_auxent *in = (union internal_auxent *) in1; |
| 224 | |
| 225 | if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type) |
| 226 | || ISTAG (in_class)) |
| 227 | { |
| 228 | ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE); |
| 229 | } |
| 230 | } |
| 231 | |
| 232 | static void |
| 233 | adjust_aux_out_pre (bfd *abfd ATTRIBUTE_UNUSED, |
| 234 | void * inp, |
| 235 | int type, |
| 236 | int in_class, |
| 237 | int indx ATTRIBUTE_UNUSED, |
| 238 | int numaux ATTRIBUTE_UNUSED, |
| 239 | void * extp ATTRIBUTE_UNUSED) |
| 240 | { |
| 241 | union internal_auxent *in = (union internal_auxent *) inp; |
| 242 | |
| 243 | if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type) |
| 244 | || ISTAG (in_class)) |
| 245 | { |
| 246 | ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, -GO32_STUBSIZE); |
| 247 | } |
| 248 | } |
| 249 | |
| 250 | static void |
| 251 | adjust_aux_out_post (bfd *abfd ATTRIBUTE_UNUSED, |
| 252 | void * inp, |
| 253 | int type, |
| 254 | int in_class, |
| 255 | int indx ATTRIBUTE_UNUSED, |
| 256 | int numaux ATTRIBUTE_UNUSED, |
| 257 | void * extp ATTRIBUTE_UNUSED) |
| 258 | { |
| 259 | union internal_auxent *in = (union internal_auxent *) inp; |
| 260 | |
| 261 | if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type) |
| 262 | || ISTAG (in_class)) |
| 263 | { |
| 264 | ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE); |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | /* That's the function, which creates the stub. There are |
| 269 | different cases from where the stub is taken. |
| 270 | At first the environment variable $(GO32STUB) is checked and then |
| 271 | $(STUB) if it was not set. |
| 272 | If it exists and points to a valid stub the stub is taken from |
| 273 | that file. This file can be also a whole executable file, because |
| 274 | the stub is computed from the exe information at the start of that |
| 275 | file. |
| 276 | |
| 277 | If there was any error, the standard stub (compiled in this file) |
| 278 | is taken. */ |
| 279 | |
| 280 | static void |
| 281 | create_go32_stub (bfd *abfd) |
| 282 | { |
| 283 | /* Do it only once. */ |
| 284 | if (coff_data (abfd)->go32stub == NULL) |
| 285 | { |
| 286 | char *stub; |
| 287 | struct stat st; |
| 288 | int f; |
| 289 | unsigned char header[10]; |
| 290 | char magic[8]; |
| 291 | unsigned long coff_start; |
| 292 | long exe_start; |
| 293 | |
| 294 | /* Check at first the environment variable $(GO32STUB). */ |
| 295 | stub = getenv ("GO32STUB"); |
| 296 | /* Now check the environment variable $(STUB). */ |
| 297 | if (stub == NULL) |
| 298 | stub = getenv ("STUB"); |
| 299 | if (stub == NULL) |
| 300 | goto stub_end; |
| 301 | if (stat (stub, &st) != 0) |
| 302 | goto stub_end; |
| 303 | #ifdef O_BINARY |
| 304 | f = open (stub, O_RDONLY | O_BINARY); |
| 305 | #else |
| 306 | f = open (stub, O_RDONLY); |
| 307 | #endif |
| 308 | if (f < 0) |
| 309 | goto stub_end; |
| 310 | if (read (f, &header, sizeof (header)) < 0) |
| 311 | { |
| 312 | close (f); |
| 313 | goto stub_end; |
| 314 | } |
| 315 | if (_H (0) != 0x5a4d) /* It is not an exe file. */ |
| 316 | { |
| 317 | close (f); |
| 318 | goto stub_end; |
| 319 | } |
| 320 | /* Compute the size of the stub (it is every thing up |
| 321 | to the beginning of the coff image). */ |
| 322 | coff_start = (long) _H (2) * 512L; |
| 323 | if (_H (1)) |
| 324 | coff_start += (long) _H (1) - 512L; |
| 325 | |
| 326 | /* Currently there is only a fixed stub size of 2048 bytes |
| 327 | supported. */ |
| 328 | if (coff_start != 2048) |
| 329 | { |
| 330 | close (f); |
| 331 | goto stub_end; |
| 332 | } |
| 333 | exe_start = _H (4) * 16; |
| 334 | if ((long) lseek (f, exe_start, SEEK_SET) != exe_start) |
| 335 | { |
| 336 | close (f); |
| 337 | goto stub_end; |
| 338 | } |
| 339 | if (read (f, &magic, 8) != 8) |
| 340 | { |
| 341 | close (f); |
| 342 | goto stub_end; |
| 343 | } |
| 344 | if (! CONST_STRNEQ (magic, "go32stub")) |
| 345 | { |
| 346 | close (f); |
| 347 | goto stub_end; |
| 348 | } |
| 349 | /* Now we found a correct stub (hopefully). */ |
| 350 | coff_data (abfd)->go32stub = bfd_alloc (abfd, (bfd_size_type) coff_start); |
| 351 | if (coff_data (abfd)->go32stub == NULL) |
| 352 | { |
| 353 | close (f); |
| 354 | return; |
| 355 | } |
| 356 | lseek (f, 0L, SEEK_SET); |
| 357 | if ((unsigned long) read (f, coff_data (abfd)->go32stub, coff_start) |
| 358 | != coff_start) |
| 359 | { |
| 360 | bfd_release (abfd, coff_data (abfd)->go32stub); |
| 361 | coff_data (abfd)->go32stub = NULL; |
| 362 | } |
| 363 | close (f); |
| 364 | } |
| 365 | stub_end: |
| 366 | /* There was something wrong above, so use now the standard builtin |
| 367 | stub. */ |
| 368 | if (coff_data (abfd)->go32stub == NULL) |
| 369 | { |
| 370 | coff_data (abfd)->go32stub |
| 371 | = bfd_alloc (abfd, (bfd_size_type) GO32_STUBSIZE); |
| 372 | if (coff_data (abfd)->go32stub == NULL) |
| 373 | return; |
| 374 | memcpy (coff_data (abfd)->go32stub, stub_bytes, GO32_STUBSIZE); |
| 375 | } |
| 376 | } |
| 377 | |
| 378 | /* If ibfd was a stubbed coff image, copy the stub from that bfd |
| 379 | to the new obfd. */ |
| 380 | |
| 381 | static bfd_boolean |
| 382 | go32_stubbed_coff_bfd_copy_private_bfd_data (bfd *ibfd, bfd *obfd) |
| 383 | { |
| 384 | /* Check if both are the same targets. */ |
| 385 | if (ibfd->xvec != obfd->xvec) |
| 386 | return TRUE; |
| 387 | |
| 388 | /* Check if we have a source stub. */ |
| 389 | if (coff_data (ibfd)->go32stub == NULL) |
| 390 | return TRUE; |
| 391 | |
| 392 | /* As adjust_filehdr_out_pre may get called only after this function, |
| 393 | optionally allocate the output stub. */ |
| 394 | if (coff_data (obfd)->go32stub == NULL) |
| 395 | coff_data (obfd)->go32stub = bfd_alloc (obfd, |
| 396 | (bfd_size_type) GO32_STUBSIZE); |
| 397 | |
| 398 | /* Now copy the stub. */ |
| 399 | if (coff_data (obfd)->go32stub != NULL) |
| 400 | memcpy (coff_data (obfd)->go32stub, coff_data (ibfd)->go32stub, |
| 401 | GO32_STUBSIZE); |
| 402 | |
| 403 | return TRUE; |
| 404 | } |
| 405 | |
| 406 | /* coff_object_p only checks 2 bytes F_MAGIC at GO32_STUBSIZE inside the file |
| 407 | which is too fragile. */ |
| 408 | |
| 409 | static const bfd_target * |
| 410 | go32_check_format (bfd *abfd) |
| 411 | { |
| 412 | char mz[2]; |
| 413 | |
| 414 | if (bfd_bread (mz, 2, abfd) != 2 || mz[0] != 'M' || mz[1] != 'Z') |
| 415 | { |
| 416 | bfd_set_error (bfd_error_wrong_format); |
| 417 | return NULL; |
| 418 | } |
| 419 | |
| 420 | if (bfd_seek (abfd, 0, SEEK_SET) != 0) |
| 421 | return NULL; |
| 422 | |
| 423 | return coff_object_p (abfd); |
| 424 | } |