| 1 | /* Copyright (C) 1985-1988, 1992-1994, 2001-2011 Free Software Foundation, Inc. |
| 2 | |
| 3 | This file is part of GNU Emacs. |
| 4 | |
| 5 | GNU Emacs is free software: you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation, either version 3 of the License, or |
| 8 | (at your option) any later version. |
| 9 | |
| 10 | GNU Emacs is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | |
| 19 | /* |
| 20 | * unexcoff.c - Convert a running program into an a.out or COFF file. |
| 21 | * |
| 22 | * ================================================================== |
| 23 | * Note: This file is currently used only by the MSDOS (a.k.a. DJGPP) |
| 24 | * build of Emacs. If you are not interested in the MSDOS build, you |
| 25 | * are looking at the wrong version of unexec! |
| 26 | * ================================================================== |
| 27 | * |
| 28 | * Author: Spencer W. Thomas |
| 29 | * Computer Science Dept. |
| 30 | * University of Utah |
| 31 | * Date: Tue Mar 2 1982 |
| 32 | * Originally under the name unexec.c. |
| 33 | * Modified heavily since then. |
| 34 | * |
| 35 | * Synopsis: |
| 36 | * unexec (const char *new_name, const char *old_name); |
| 37 | * |
| 38 | * Takes a snapshot of the program and makes an a.out format file in the |
| 39 | * file named by the string argument new_name. |
| 40 | * If a_name is non-NULL, the symbol table will be taken from the given file. |
| 41 | * On some machines, an existing a_name file is required. |
| 42 | * |
| 43 | * If you make improvements I'd like to get them too. |
| 44 | * harpo!utah-cs!thomas, thomas@Utah-20 |
| 45 | * |
| 46 | */ |
| 47 | |
| 48 | /* Modified to support SysVr3 shared libraries by James Van Artsdalen |
| 49 | * of Dell Computer Corporation. james@bigtex.cactus.org. |
| 50 | */ |
| 51 | |
| 52 | #include <config.h> |
| 53 | #define PERROR(file) report_error (file, new) |
| 54 | |
| 55 | #ifndef CANNOT_DUMP /* all rest of file! */ |
| 56 | |
| 57 | #ifdef HAVE_COFF_H |
| 58 | #include <coff.h> |
| 59 | #ifdef MSDOS |
| 60 | #include <fcntl.h> /* for O_RDONLY, O_RDWR */ |
| 61 | #include <crt0.h> /* for _crt0_startup_flags and its bits */ |
| 62 | #include <sys/exceptn.h> |
| 63 | static int save_djgpp_startup_flags; |
| 64 | #define filehdr external_filehdr |
| 65 | #define scnhdr external_scnhdr |
| 66 | #define syment external_syment |
| 67 | #define auxent external_auxent |
| 68 | #define n_numaux e_numaux |
| 69 | #define n_type e_type |
| 70 | struct aouthdr |
| 71 | { |
| 72 | unsigned short magic; /* type of file */ |
| 73 | unsigned short vstamp; /* version stamp */ |
| 74 | unsigned long tsize; /* text size in bytes, padded to FW bdry*/ |
| 75 | unsigned long dsize; /* initialized data " " */ |
| 76 | unsigned long bsize; /* uninitialized data " " */ |
| 77 | unsigned long entry; /* entry pt. */ |
| 78 | unsigned long text_start;/* base of text used for this file */ |
| 79 | unsigned long data_start;/* base of data used for this file */ |
| 80 | }; |
| 81 | #endif /* not MSDOS */ |
| 82 | #else /* not HAVE_COFF_H */ |
| 83 | #include <a.out.h> |
| 84 | #endif /* not HAVE_COFF_H */ |
| 85 | |
| 86 | /* Define getpagesize if the system does not. |
| 87 | Note that this may depend on symbols defined in a.out.h. */ |
| 88 | #include "getpagesize.h" |
| 89 | |
| 90 | #ifndef makedev /* Try to detect types.h already loaded */ |
| 91 | #include <sys/types.h> |
| 92 | #endif /* makedev */ |
| 93 | #include <stdio.h> |
| 94 | #include <sys/stat.h> |
| 95 | #include <errno.h> |
| 96 | |
| 97 | #include <sys/file.h> |
| 98 | |
| 99 | extern char *start_of_data (void); /* Start of initialized data */ |
| 100 | |
| 101 | static long block_copy_start; /* Old executable start point */ |
| 102 | static struct filehdr f_hdr; /* File header */ |
| 103 | static struct aouthdr f_ohdr; /* Optional file header (a.out) */ |
| 104 | long bias; /* Bias to add for growth */ |
| 105 | long lnnoptr; /* Pointer to line-number info within file */ |
| 106 | #define SYMS_START block_copy_start |
| 107 | |
| 108 | static long text_scnptr; |
| 109 | static long data_scnptr; |
| 110 | |
| 111 | static long coff_offset; |
| 112 | |
| 113 | static int pagemask; |
| 114 | |
| 115 | /* Correct an int which is the bit pattern of a pointer to a byte |
| 116 | into an int which is the number of a byte. |
| 117 | This is a no-op on ordinary machines, but not on all. */ |
| 118 | |
| 119 | #define ADDR_CORRECT(x) ((char *)(x) - (char*)0) |
| 120 | |
| 121 | #include <setjmp.h> |
| 122 | #include "lisp.h" |
| 123 | |
| 124 | static void |
| 125 | report_error (const char *file, int fd) |
| 126 | { |
| 127 | if (fd) |
| 128 | close (fd); |
| 129 | report_file_error ("Cannot unexec", Fcons (build_string (file), Qnil)); |
| 130 | } |
| 131 | |
| 132 | #define ERROR0(msg) report_error_1 (new, msg, 0, 0); return -1 |
| 133 | #define ERROR1(msg,x) report_error_1 (new, msg, x, 0); return -1 |
| 134 | #define ERROR2(msg,x,y) report_error_1 (new, msg, x, y); return -1 |
| 135 | |
| 136 | static void |
| 137 | report_error_1 (int fd, const char *msg, int a1, int a2) |
| 138 | { |
| 139 | close (fd); |
| 140 | error (msg, a1, a2); |
| 141 | } |
| 142 | \f |
| 143 | static int make_hdr (int, int, const char *, const char *); |
| 144 | static int copy_text_and_data (int, int); |
| 145 | static int copy_sym (int, int, const char *, const char *); |
| 146 | static void mark_x (const char *); |
| 147 | |
| 148 | /* **************************************************************** |
| 149 | * make_hdr |
| 150 | * |
| 151 | * Make the header in the new a.out from the header in core. |
| 152 | * Modify the text and data sizes. |
| 153 | */ |
| 154 | static int |
| 155 | make_hdr (int new, int a_out, |
| 156 | const char *a_name, const char *new_name) |
| 157 | { |
| 158 | auto struct scnhdr f_thdr; /* Text section header */ |
| 159 | auto struct scnhdr f_dhdr; /* Data section header */ |
| 160 | auto struct scnhdr f_bhdr; /* Bss section header */ |
| 161 | auto struct scnhdr scntemp; /* Temporary section header */ |
| 162 | register int scns; |
| 163 | unsigned int bss_start; |
| 164 | unsigned int data_start; |
| 165 | |
| 166 | pagemask = getpagesize () - 1; |
| 167 | |
| 168 | /* Adjust text/data boundary. */ |
| 169 | data_start = (int) start_of_data (); |
| 170 | data_start = ADDR_CORRECT (data_start); |
| 171 | data_start = data_start & ~pagemask; /* (Down) to page boundary. */ |
| 172 | |
| 173 | bss_start = ADDR_CORRECT (sbrk (0)) + pagemask; |
| 174 | bss_start &= ~ pagemask; |
| 175 | |
| 176 | if (data_start > bss_start) /* Can't have negative data size. */ |
| 177 | { |
| 178 | ERROR2 ("unexec: data_start (%u) can't be greater than bss_start (%u)", |
| 179 | data_start, bss_start); |
| 180 | } |
| 181 | |
| 182 | coff_offset = 0L; /* stays zero, except in DJGPP */ |
| 183 | |
| 184 | /* Salvage as much info from the existing file as possible */ |
| 185 | if (a_out >= 0) |
| 186 | { |
| 187 | #ifdef MSDOS |
| 188 | /* Support the coff-go32-exe format with a prepended stub, since |
| 189 | this is what GCC 2.8.0 and later generates by default in DJGPP. */ |
| 190 | unsigned short mz_header[3]; |
| 191 | |
| 192 | if (read (a_out, &mz_header, sizeof (mz_header)) != sizeof (mz_header)) |
| 193 | { |
| 194 | PERROR (a_name); |
| 195 | } |
| 196 | if (mz_header[0] == 0x5a4d || mz_header[0] == 0x4d5a) /* "MZ" or "ZM" */ |
| 197 | { |
| 198 | coff_offset = (long)mz_header[2] * 512L; |
| 199 | if (mz_header[1]) |
| 200 | coff_offset += (long)mz_header[1] - 512L; |
| 201 | lseek (a_out, coff_offset, 0); |
| 202 | } |
| 203 | else |
| 204 | lseek (a_out, 0L, 0); |
| 205 | #endif /* MSDOS */ |
| 206 | if (read (a_out, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr)) |
| 207 | { |
| 208 | PERROR (a_name); |
| 209 | } |
| 210 | block_copy_start += sizeof (f_hdr); |
| 211 | if (f_hdr.f_opthdr > 0) |
| 212 | { |
| 213 | if (read (a_out, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr)) |
| 214 | { |
| 215 | PERROR (a_name); |
| 216 | } |
| 217 | block_copy_start += sizeof (f_ohdr); |
| 218 | } |
| 219 | /* Loop through section headers, copying them in */ |
| 220 | lseek (a_out, coff_offset + sizeof (f_hdr) + f_hdr.f_opthdr, 0); |
| 221 | for (scns = f_hdr.f_nscns; scns > 0; scns--) { |
| 222 | if (read (a_out, &scntemp, sizeof (scntemp)) != sizeof (scntemp)) |
| 223 | { |
| 224 | PERROR (a_name); |
| 225 | } |
| 226 | if (scntemp.s_scnptr > 0L) |
| 227 | { |
| 228 | if (block_copy_start < scntemp.s_scnptr + scntemp.s_size) |
| 229 | block_copy_start = scntemp.s_scnptr + scntemp.s_size; |
| 230 | } |
| 231 | if (strcmp (scntemp.s_name, ".text") == 0) |
| 232 | { |
| 233 | f_thdr = scntemp; |
| 234 | } |
| 235 | else if (strcmp (scntemp.s_name, ".data") == 0) |
| 236 | { |
| 237 | f_dhdr = scntemp; |
| 238 | } |
| 239 | else if (strcmp (scntemp.s_name, ".bss") == 0) |
| 240 | { |
| 241 | f_bhdr = scntemp; |
| 242 | } |
| 243 | } |
| 244 | } |
| 245 | else |
| 246 | { |
| 247 | ERROR0 ("can't build a COFF file from scratch yet"); |
| 248 | } |
| 249 | |
| 250 | /* Now we alter the contents of all the f_*hdr variables |
| 251 | to correspond to what we want to dump. */ |
| 252 | |
| 253 | f_hdr.f_flags |= (F_RELFLG | F_EXEC); |
| 254 | f_ohdr.dsize = bss_start - f_ohdr.data_start; |
| 255 | f_ohdr.bsize = 0; |
| 256 | f_thdr.s_size = f_ohdr.tsize; |
| 257 | f_thdr.s_scnptr = sizeof (f_hdr) + sizeof (f_ohdr); |
| 258 | f_thdr.s_scnptr += (f_hdr.f_nscns) * (sizeof (f_thdr)); |
| 259 | lnnoptr = f_thdr.s_lnnoptr; |
| 260 | text_scnptr = f_thdr.s_scnptr; |
| 261 | f_dhdr.s_paddr = f_ohdr.data_start; |
| 262 | f_dhdr.s_vaddr = f_ohdr.data_start; |
| 263 | f_dhdr.s_size = f_ohdr.dsize; |
| 264 | f_dhdr.s_scnptr = f_thdr.s_scnptr + f_thdr.s_size; |
| 265 | data_scnptr = f_dhdr.s_scnptr; |
| 266 | f_bhdr.s_paddr = f_ohdr.data_start + f_ohdr.dsize; |
| 267 | f_bhdr.s_vaddr = f_ohdr.data_start + f_ohdr.dsize; |
| 268 | f_bhdr.s_size = f_ohdr.bsize; |
| 269 | f_bhdr.s_scnptr = 0L; |
| 270 | bias = f_dhdr.s_scnptr + f_dhdr.s_size - block_copy_start; |
| 271 | |
| 272 | if (f_hdr.f_symptr > 0L) |
| 273 | { |
| 274 | f_hdr.f_symptr += bias; |
| 275 | } |
| 276 | |
| 277 | if (f_thdr.s_lnnoptr > 0L) |
| 278 | { |
| 279 | f_thdr.s_lnnoptr += bias; |
| 280 | } |
| 281 | |
| 282 | if (write (new, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr)) |
| 283 | { |
| 284 | PERROR (new_name); |
| 285 | } |
| 286 | |
| 287 | if (write (new, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr)) |
| 288 | { |
| 289 | PERROR (new_name); |
| 290 | } |
| 291 | |
| 292 | if (write (new, &f_thdr, sizeof (f_thdr)) != sizeof (f_thdr)) |
| 293 | { |
| 294 | PERROR (new_name); |
| 295 | } |
| 296 | |
| 297 | if (write (new, &f_dhdr, sizeof (f_dhdr)) != sizeof (f_dhdr)) |
| 298 | { |
| 299 | PERROR (new_name); |
| 300 | } |
| 301 | |
| 302 | if (write (new, &f_bhdr, sizeof (f_bhdr)) != sizeof (f_bhdr)) |
| 303 | { |
| 304 | PERROR (new_name); |
| 305 | } |
| 306 | |
| 307 | return (0); |
| 308 | |
| 309 | } |
| 310 | \f |
| 311 | void |
| 312 | write_segment (int new, const char *ptr, const char *end) |
| 313 | { |
| 314 | register int i, nwrite, ret; |
| 315 | /* This is the normal amount to write at once. |
| 316 | It is the size of block that NFS uses. */ |
| 317 | int writesize = 1 << 13; |
| 318 | int pagesize = getpagesize (); |
| 319 | char zeros[1 << 13]; |
| 320 | |
| 321 | memset (zeros, 0, sizeof (zeros)); |
| 322 | |
| 323 | for (i = 0; ptr < end;) |
| 324 | { |
| 325 | /* Distance to next multiple of writesize. */ |
| 326 | nwrite = (((int) ptr + writesize) & -writesize) - (int) ptr; |
| 327 | /* But not beyond specified end. */ |
| 328 | if (nwrite > end - ptr) nwrite = end - ptr; |
| 329 | ret = write (new, ptr, nwrite); |
| 330 | /* If write gets a page fault, it means we reached |
| 331 | a gap between the old text segment and the old data segment. |
| 332 | This gap has probably been remapped into part of the text segment. |
| 333 | So write zeros for it. */ |
| 334 | if (ret == -1 |
| 335 | #ifdef EFAULT |
| 336 | && errno == EFAULT |
| 337 | #endif |
| 338 | ) |
| 339 | { |
| 340 | /* Write only a page of zeros at once, |
| 341 | so that we don't overshoot the start |
| 342 | of the valid memory in the old data segment. */ |
| 343 | if (nwrite > pagesize) |
| 344 | nwrite = pagesize; |
| 345 | write (new, zeros, nwrite); |
| 346 | } |
| 347 | i += nwrite; |
| 348 | ptr += nwrite; |
| 349 | } |
| 350 | } |
| 351 | /* **************************************************************** |
| 352 | * copy_text_and_data |
| 353 | * |
| 354 | * Copy the text and data segments from memory to the new a.out |
| 355 | */ |
| 356 | static int |
| 357 | copy_text_and_data (int new, int a_out) |
| 358 | { |
| 359 | register char *end; |
| 360 | register char *ptr; |
| 361 | |
| 362 | #ifdef MSDOS |
| 363 | /* Dump the original table of exception handlers, not the one |
| 364 | where our exception hooks are registered. */ |
| 365 | __djgpp_exception_toggle (); |
| 366 | |
| 367 | /* Switch off startup flags that might have been set at runtime |
| 368 | and which might change the way that dumped Emacs works. */ |
| 369 | save_djgpp_startup_flags = _crt0_startup_flags; |
| 370 | _crt0_startup_flags &= ~(_CRT0_FLAG_NO_LFN | _CRT0_FLAG_NEARPTR); |
| 371 | #endif |
| 372 | |
| 373 | lseek (new, (long) text_scnptr, 0); |
| 374 | ptr = (char *) f_ohdr.text_start; |
| 375 | end = ptr + f_ohdr.tsize; |
| 376 | write_segment (new, ptr, end); |
| 377 | |
| 378 | lseek (new, (long) data_scnptr, 0); |
| 379 | ptr = (char *) f_ohdr.data_start; |
| 380 | end = ptr + f_ohdr.dsize; |
| 381 | write_segment (new, ptr, end); |
| 382 | |
| 383 | #ifdef MSDOS |
| 384 | /* Restore our exception hooks. */ |
| 385 | __djgpp_exception_toggle (); |
| 386 | |
| 387 | /* Restore the startup flags. */ |
| 388 | _crt0_startup_flags = save_djgpp_startup_flags; |
| 389 | #endif |
| 390 | |
| 391 | |
| 392 | return 0; |
| 393 | } |
| 394 | \f |
| 395 | /* **************************************************************** |
| 396 | * copy_sym |
| 397 | * |
| 398 | * Copy the relocation information and symbol table from the a.out to the new |
| 399 | */ |
| 400 | static int |
| 401 | copy_sym (int new, int a_out, const char *a_name, const char *new_name) |
| 402 | { |
| 403 | char page[1024]; |
| 404 | int n; |
| 405 | |
| 406 | if (a_out < 0) |
| 407 | return 0; |
| 408 | |
| 409 | if (SYMS_START == 0L) |
| 410 | return 0; |
| 411 | |
| 412 | if (lnnoptr) /* if there is line number info */ |
| 413 | lseek (a_out, coff_offset + lnnoptr, 0); /* start copying from there */ |
| 414 | else |
| 415 | lseek (a_out, coff_offset + SYMS_START, 0); /* Position a.out to symtab. */ |
| 416 | |
| 417 | while ((n = read (a_out, page, sizeof page)) > 0) |
| 418 | { |
| 419 | if (write (new, page, n) != n) |
| 420 | { |
| 421 | PERROR (new_name); |
| 422 | } |
| 423 | } |
| 424 | if (n < 0) |
| 425 | { |
| 426 | PERROR (a_name); |
| 427 | } |
| 428 | return 0; |
| 429 | } |
| 430 | \f |
| 431 | /* **************************************************************** |
| 432 | * mark_x |
| 433 | * |
| 434 | * After successfully building the new a.out, mark it executable |
| 435 | */ |
| 436 | static void |
| 437 | mark_x (const char *name) |
| 438 | { |
| 439 | struct stat sbuf; |
| 440 | int um; |
| 441 | int new = 0; /* for PERROR */ |
| 442 | |
| 443 | um = umask (777); |
| 444 | umask (um); |
| 445 | if (stat (name, &sbuf) == -1) |
| 446 | { |
| 447 | PERROR (name); |
| 448 | } |
| 449 | sbuf.st_mode |= 0111 & ~um; |
| 450 | if (chmod (name, sbuf.st_mode) == -1) |
| 451 | PERROR (name); |
| 452 | } |
| 453 | \f |
| 454 | |
| 455 | /* |
| 456 | * If the COFF file contains a symbol table and a line number section, |
| 457 | * then any auxiliary entries that have values for x_lnnoptr must |
| 458 | * be adjusted by the amount that the line number section has moved |
| 459 | * in the file (bias computed in make_hdr). The #@$%&* designers of |
| 460 | * the auxiliary entry structures used the absolute file offsets for |
| 461 | * the line number entry rather than an offset from the start of the |
| 462 | * line number section! |
| 463 | * |
| 464 | * When I figure out how to scan through the symbol table and pick out |
| 465 | * the auxiliary entries that need adjustment, this routine will |
| 466 | * be fixed. As it is now, all such entries are wrong and sdb |
| 467 | * will complain. Fred Fish, UniSoft Systems Inc. |
| 468 | */ |
| 469 | |
| 470 | /* This function is probably very slow. Instead of reopening the new |
| 471 | file for input and output it should copy from the old to the new |
| 472 | using the two descriptors already open (WRITEDESC and READDESC). |
| 473 | Instead of reading one small structure at a time it should use |
| 474 | a reasonable size buffer. But I don't have time to work on such |
| 475 | things, so I am installing it as submitted to me. -- RMS. */ |
| 476 | |
| 477 | int |
| 478 | adjust_lnnoptrs (int writedesc, int readdesc, const char *new_name) |
| 479 | { |
| 480 | register int nsyms; |
| 481 | register int new; |
| 482 | struct syment symentry; |
| 483 | union auxent auxentry; |
| 484 | |
| 485 | if (!lnnoptr || !f_hdr.f_symptr) |
| 486 | return 0; |
| 487 | |
| 488 | #ifdef MSDOS |
| 489 | if ((new = writedesc) < 0) |
| 490 | #else |
| 491 | if ((new = open (new_name, O_RDWR)) < 0) |
| 492 | #endif |
| 493 | { |
| 494 | PERROR (new_name); |
| 495 | return -1; |
| 496 | } |
| 497 | |
| 498 | lseek (new, f_hdr.f_symptr, 0); |
| 499 | for (nsyms = 0; nsyms < f_hdr.f_nsyms; nsyms++) |
| 500 | { |
| 501 | read (new, &symentry, SYMESZ); |
| 502 | if (symentry.n_numaux) |
| 503 | { |
| 504 | read (new, &auxentry, AUXESZ); |
| 505 | nsyms++; |
| 506 | if (ISFCN (symentry.n_type) || symentry.n_type == 0x2400) |
| 507 | { |
| 508 | auxentry.x_sym.x_fcnary.x_fcn.x_lnnoptr += bias; |
| 509 | lseek (new, -AUXESZ, 1); |
| 510 | write (new, &auxentry, AUXESZ); |
| 511 | } |
| 512 | } |
| 513 | } |
| 514 | #ifndef MSDOS |
| 515 | close (new); |
| 516 | #endif |
| 517 | return 0; |
| 518 | } |
| 519 | |
| 520 | /* **************************************************************** |
| 521 | * unexec |
| 522 | * |
| 523 | * driving logic. |
| 524 | */ |
| 525 | int |
| 526 | unexec (const char *new_name, const char *a_name) |
| 527 | { |
| 528 | int new = -1, a_out = -1; |
| 529 | |
| 530 | if (a_name && (a_out = open (a_name, O_RDONLY)) < 0) |
| 531 | { |
| 532 | PERROR (a_name); |
| 533 | } |
| 534 | if ((new = creat (new_name, 0666)) < 0) |
| 535 | { |
| 536 | PERROR (new_name); |
| 537 | } |
| 538 | |
| 539 | if (make_hdr (new, a_out, a_name, new_name) < 0 |
| 540 | || copy_text_and_data (new, a_out) < 0 |
| 541 | || copy_sym (new, a_out, a_name, new_name) < 0 |
| 542 | || adjust_lnnoptrs (new, a_out, new_name) < 0 |
| 543 | ) |
| 544 | { |
| 545 | close (new); |
| 546 | return -1; |
| 547 | } |
| 548 | |
| 549 | close (new); |
| 550 | if (a_out >= 0) |
| 551 | close (a_out); |
| 552 | mark_x (new_name); |
| 553 | return 0; |
| 554 | } |
| 555 | |
| 556 | #endif /* not CANNOT_DUMP */ |
| 557 | |