code.delx.au - gnu-emacs/blob - src/unexsgi.c

   1 /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992
   2    Free Software Foundation, Inc.
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2, or (at your option)
   7     any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 In other words, you are welcome to use, share and improve this program.
  19 You are forbidden to forbid anyone else to use, share and improve
  20 what you give them.   Help stamp out software-hoarding!  */
  21
  22
  23 /*
  24  * unexec.c - Convert a running program into an a.out file.
  25  *
  26  * Author:      Spencer W. Thomas
  27  *              Computer Science Dept.
  28  *              University of Utah
  29  * Date:        Tue Mar  2 1982
  30  * Modified heavily since then.
  31  *
  32  * Synopsis:
  33  *      unexec (new_name, a_name, data_start, bss_start, entry_address)
  34  *      char *new_name, *a_name;
  35  *      unsigned data_start, bss_start, entry_address;
  36  *
  37  * Takes a snapshot of the program and makes an a.out format file in the
  38  * file named by the string argument new_name.
  39  * If a_name is non-NULL, the symbol table will be taken from the given file.
  40  * On some machines, an existing a_name file is required.
  41  *
  42  * The boundaries within the a.out file may be adjusted with the data_start
  43  * and bss_start arguments.  Either or both may be given as 0 for defaults.
  44  *
  45  * Data_start gives the boundary between the text segment and the data
  46  * segment of the program.  The text segment can contain shared, read-only
  47  * program code and literal data, while the data segment is always unshared
  48  * and unprotected.  Data_start gives the lowest unprotected address.
  49  * The value you specify may be rounded down to a suitable boundary
  50  * as required by the machine you are using.
  51  *
  52  * Specifying zero for data_start means the boundary between text and data
  53  * should not be the same as when the program was loaded.
  54  * If NO_REMAP is defined, the argument data_start is ignored and the
  55  * segment boundaries are never changed.
  56  *
  57  * Bss_start indicates how much of the data segment is to be saved in the
  58  * a.out file and restored when the program is executed.  It gives the lowest
  59  * unsaved address, and is rounded up to a page boundary.  The default when 0
  60  * is given assumes that the entire data segment is to be stored, including
  61  * the previous data and bss as well as any additional storage allocated with
  62  * break (2).
  63  *
  64  * The new file is set up to start at entry_address.
  65  *
  66  * If you make improvements I'd like to get them too.
  67  * harpo!utah-cs!thomas, thomas@Utah-20
  68  *
  69  */
  70
  71 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
  72  * ELF support added.
  73  *
  74  * Basic theory: the data space of the running process needs to be
  75  * dumped to the output file.  Normally we would just enlarge the size
  76  * of .data, scooting everything down.  But we can't do that in ELF,
  77  * because there is often something between the .data space and the
  78  * .bss space.
  79  *
  80  * In the temacs dump below, notice that the Global Offset Table
  81  * (.got) and the Dynamic link data (.dynamic) come between .data1 and
  82  * .bss.  It does not work to overlap .data with these fields.
  83  *
  84  * The solution is to create a new .data segment.  This segment is
  85  * filled with data from the current process.  Since the contents of
  86  * various sections refer to sections by index, the new .data segment
  87  * is made the last in the table to avoid changing any existing index.
  88
  89  * This is an example of how the section headers are changed.  "Addr"
  90  * is a process virtual address.  "Offset" is a file offset.
  91
  92 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
  93
  94 temacs:
  95
  96            **** SECTION HEADER TABLE ****
  97 [No]    Type    Flags   Addr         Offset       Size          Name
  98         Link    Info    Adralgn      Entsize
  99
 100 [1]     1       2       0x80480d4    0xd4         0x13          .interp
 101         0       0       0x1          0
 102
 103 [2]     5       2       0x80480e8    0xe8         0x388         .hash
 104         3       0       0x4          0x4
 105
 106 [3]     11      2       0x8048470    0x470        0x7f0         .dynsym
 107         4       1       0x4          0x10
 108
 109 [4]     3       2       0x8048c60    0xc60        0x3ad         .dynstr
 110         0       0       0x1          0
 111
 112 [5]     9       2       0x8049010    0x1010       0x338         .rel.plt
 113         3       7       0x4          0x8
 114
 115 [6]     1       6       0x8049348    0x1348       0x3           .init
 116         0       0       0x4          0
 117
 118 [7]     1       6       0x804934c    0x134c       0x680         .plt
 119         0       0       0x4          0x4
 120
 121 [8]     1       6       0x80499cc    0x19cc       0x3c56f       .text
 122         0       0       0x4          0
 123
 124 [9]     1       6       0x8085f3c    0x3df3c      0x3           .fini
 125         0       0       0x4          0
 126
 127 [10]    1       2       0x8085f40    0x3df40      0x69c         .rodata
 128         0       0       0x4          0
 129
 130 [11]    1       2       0x80865dc    0x3e5dc      0xd51         .rodata1
 131         0       0       0x4          0
 132
 133 [12]    1       3       0x8088330    0x3f330      0x20afc       .data
 134         0       0       0x4          0
 135
 136 [13]    1       3       0x80a8e2c    0x5fe2c      0x89d         .data1
 137         0       0       0x4          0
 138
 139 [14]    1       3       0x80a96cc    0x606cc      0x1a8         .got
 140         0       0       0x4          0x4
 141
 142 [15]    6       3       0x80a9874    0x60874      0x80          .dynamic
 143         4       0       0x4          0x8
 144
 145 [16]    8       3       0x80a98f4    0x608f4      0x449c        .bss
 146         0       0       0x4          0
 147
 148 [17]    2       0       0            0x608f4      0x9b90        .symtab
 149         18      371     0x4          0x10
 150
 151 [18]    3       0       0            0x6a484      0x8526        .strtab
 152         0       0       0x1          0
 153
 154 [19]    3       0       0            0x729aa      0x93          .shstrtab
 155         0       0       0x1          0
 156
 157 [20]    1       0       0            0x72a3d      0x68b7        .comment
 158         0       0       0x1          0
 159
 160 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
 161
 162 xemacs:
 163
 164            **** SECTION HEADER TABLE ****
 165 [No]    Type    Flags   Addr         Offset       Size          Name
 166         Link    Info    Adralgn      Entsize
 167
 168 [1]     1       2       0x80480d4    0xd4         0x13          .interp
 169         0       0       0x1          0
 170
 171 [2]     5       2       0x80480e8    0xe8         0x388         .hash
 172         3       0       0x4          0x4
 173
 174 [3]     11      2       0x8048470    0x470        0x7f0         .dynsym
 175         4       1       0x4          0x10
 176
 177 [4]     3       2       0x8048c60    0xc60        0x3ad         .dynstr
 178         0       0       0x1          0
 179
 180 [5]     9       2       0x8049010    0x1010       0x338         .rel.plt
 181         3       7       0x4          0x8
 182
 183 [6]     1       6       0x8049348    0x1348       0x3           .init
 184         0       0       0x4          0
 185
 186 [7]     1       6       0x804934c    0x134c       0x680         .plt
 187         0       0       0x4          0x4
 188
 189 [8]     1       6       0x80499cc    0x19cc       0x3c56f       .text
 190         0       0       0x4          0
 191
 192 [9]     1       6       0x8085f3c    0x3df3c      0x3           .fini
 193         0       0       0x4          0
 194
 195 [10]    1       2       0x8085f40    0x3df40      0x69c         .rodata
 196         0       0       0x4          0
 197
 198 [11]    1       2       0x80865dc    0x3e5dc      0xd51         .rodata1
 199         0       0       0x4          0
 200
 201 [12]    1       3       0x8088330    0x3f330      0x20afc       .data
 202         0       0       0x4          0
 203
 204 [13]    1       3       0x80a8e2c    0x5fe2c      0x89d         .data1
 205         0       0       0x4          0
 206
 207 [14]    1       3       0x80a96cc    0x606cc      0x1a8         .got
 208         0       0       0x4          0x4
 209
 210 [15]    6       3       0x80a9874    0x60874      0x80          .dynamic
 211         4       0       0x4          0x8
 212
 213 [16]    8       3       0x80c6800    0x7d800      0             .bss
 214         0       0       0x4          0
 215
 216 [17]    2       0       0            0x7d800      0x9b90        .symtab
 217         18      371     0x4          0x10
 218
 219 [18]    3       0       0            0x87390      0x8526        .strtab
 220         0       0       0x1          0
 221
 222 [19]    3       0       0            0x8f8b6      0x93          .shstrtab
 223         0       0       0x1          0
 224
 225 [20]    1       0       0            0x8f949      0x68b7        .comment
 226         0       0       0x1          0
 227
 228 [21]    1       3       0x80a98f4    0x608f4      0x1cf0c       .data
 229         0       0       0x4          0
 230
 231  * This is an example of how the file header is changed.  "Shoff" is
 232  * the section header offset within the file.  Since that table is
 233  * after the new .data section, it is moved.  "Shnum" is the number of
 234  * sections, which we increment.
 235  *
 236  * "Phoff" is the file offset to the program header.  "Phentsize" and
 237  * "Shentsz" are the program and section header entries sizes respectively.
 238  * These can be larger than the apparent struct sizes.
 239
 240 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
 241
 242 temacs:
 243
 244                     **** ELF HEADER ****
 245 Class        Data       Type         Machine     Version
 246 Entry        Phoff      Shoff        Flags       Ehsize
 247 Phentsize    Phnum      Shentsz      Shnum       Shstrndx
 248
 249 1            1          2            3           1
 250 0x80499cc    0x34       0x792f4      0           0x34
 251 0x20         5          0x28         21          19
 252
 253 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
 254
 255 xemacs:
 256
 257                     **** ELF HEADER ****
 258 Class        Data       Type         Machine     Version
 259 Entry        Phoff      Shoff        Flags       Ehsize
 260 Phentsize    Phnum      Shentsz      Shnum       Shstrndx
 261
 262 1            1          2            3           1
 263 0x80499cc    0x34       0x96200      0           0x34
 264 0x20         5          0x28         22          19
 265
 266  * These are the program headers.  "Offset" is the file offset to the
 267  * segment.  "Vaddr" is the memory load address.  "Filesz" is the
 268  * segment size as it appears in the file, and "Memsz" is the size in
 269  * memory.  Below, the third segment is the code and the fourth is the
 270  * data: the difference between Filesz and Memsz is .bss
 271
 272 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
 273
 274 temacs:
 275  ***** PROGRAM EXECUTION HEADER *****
 276 Type        Offset      Vaddr       Paddr
 277 Filesz      Memsz       Flags       Align
 278
 279 6           0x34        0x8048034   0
 280 0xa0        0xa0        5           0
 281
 282 3           0xd4        0           0
 283 0x13        0           4           0
 284
 285 1           0x34        0x8048034   0
 286 0x3f2f9     0x3f2f9     5           0x1000
 287
 288 1           0x3f330     0x8088330   0
 289 0x215c4     0x25a60     7           0x1000
 290
 291 2           0x60874     0x80a9874   0
 292 0x80        0           7           0
 293
 294 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
 295
 296 xemacs:
 297  ***** PROGRAM EXECUTION HEADER *****
 298 Type        Offset      Vaddr       Paddr
 299 Filesz      Memsz       Flags       Align
 300
 301 6           0x34        0x8048034   0
 302 0xa0        0xa0        5           0
 303
 304 3           0xd4        0           0
 305 0x13        0           4           0
 306
 307 1           0x34        0x8048034   0
 308 0x3f2f9     0x3f2f9     5           0x1000
 309
 310 1           0x3f330     0x8088330   0
 311 0x3e4d0     0x3e4d0     7           0x1000
 312
 313 2           0x60874     0x80a9874   0
 314 0x80        0           7           0
 315
 316
 317  */
 318 \f
 319 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
 320  *
 321  * The above mechanism does not work if the unexeced ELF file is being
 322  * re-layout by other applications (such as `strip'). All the applications
 323  * that re-layout the internal of ELF will layout all sections in ascending
 324  * order of their file offsets. After the re-layout, the data2 section will
 325  * still be the LAST section in the section header vector, but its file offset
 326  * is now being pushed far away down, and causes part of it not to be mapped
 327  * in (ie. not covered by the load segment entry in PHDR vector), therefore
 328  * causes the new binary to fail.
 329  *
 330  * The solution is to modify the unexec algorithm to insert the new data2
 331  * section header right before the new bss section header, so their file
 332  * offsets will be in the ascending order. Since some of the section's (all
 333  * sections AFTER the bss section) indexes are now changed, we also need to
 334  * modify some fields to make them point to the right sections. This is done
 335  * by macro PATCH_INDEX. All the fields that need to be patched are:
 336  *
 337  * 1. ELF header e_shstrndx field.
 338  * 2. section header sh_link and sh_info field.
 339  * 3. symbol table entry st_shndx field.
 340  *
 341  * The above example now should look like:
 342
 343            **** SECTION HEADER TABLE ****
 344 [No]    Type    Flags   Addr         Offset       Size          Name
 345         Link    Info    Adralgn      Entsize
 346
 347 [1]     1       2       0x80480d4    0xd4         0x13          .interp
 348         0       0       0x1          0
 349
 350 [2]     5       2       0x80480e8    0xe8         0x388         .hash
 351         3       0       0x4          0x4
 352
 353 [3]     11      2       0x8048470    0x470        0x7f0         .dynsym
 354         4       1       0x4          0x10
 355
 356 [4]     3       2       0x8048c60    0xc60        0x3ad         .dynstr
 357         0       0       0x1          0
 358
 359 [5]     9       2       0x8049010    0x1010       0x338         .rel.plt
 360         3       7       0x4          0x8
 361
 362 [6]     1       6       0x8049348    0x1348       0x3           .init
 363         0       0       0x4          0
 364
 365 [7]     1       6       0x804934c    0x134c       0x680         .plt
 366         0       0       0x4          0x4
 367
 368 [8]     1       6       0x80499cc    0x19cc       0x3c56f       .text
 369         0       0       0x4          0
 370
 371 [9]     1       6       0x8085f3c    0x3df3c      0x3           .fini
 372         0       0       0x4          0
 373
 374 [10]    1       2       0x8085f40    0x3df40      0x69c         .rodata
 375         0       0       0x4          0
 376
 377 [11]    1       2       0x80865dc    0x3e5dc      0xd51         .rodata1
 378         0       0       0x4          0
 379
 380 [12]    1       3       0x8088330    0x3f330      0x20afc       .data
 381         0       0       0x4          0
 382
 383 [13]    1       3       0x80a8e2c    0x5fe2c      0x89d         .data1
 384         0       0       0x4          0
 385
 386 [14]    1       3       0x80a96cc    0x606cc      0x1a8         .got
 387         0       0       0x4          0x4
 388
 389 [15]    6       3       0x80a9874    0x60874      0x80          .dynamic
 390         4       0       0x4          0x8
 391
 392 [16]    1       3       0x80a98f4    0x608f4      0x1cf0c       .data
 393         0       0       0x4          0
 394
 395 [17]    8       3       0x80c6800    0x7d800      0             .bss
 396         0       0       0x4          0
 397
 398 [18]    2       0       0            0x7d800      0x9b90        .symtab
 399         19      371     0x4          0x10
 400
 401 [19]    3       0       0            0x87390      0x8526        .strtab
 402         0       0       0x1          0
 403
 404 [20]    3       0       0            0x8f8b6      0x93          .shstrtab
 405         0       0       0x1          0
 406
 407 [21]    1       0       0            0x8f949      0x68b7        .comment
 408         0       0       0x1          0
 409
 410  */
 411 \f
 412 #include <sys/types.h>
 413 #include <stdio.h>
 414 #include <sys/stat.h>
 415 #include <memory.h>
 416 #include <string.h>
 417 #include <errno.h>
 418 #include <unistd.h>
 419 #include <fcntl.h>
 420 #include <elf.h>
 421 #include <syms.h> /* for HDRR declaration */
 422 #include <sys/mman.h>
 423
 424 #ifndef emacs
 425 #define fatal(a, b, c) fprintf(stderr, a, b, c), exit(1)
 426 #else
 427 extern void fatal(char *, ...);
 428 #endif
 429
 430 /* Get the address of a particular section or program header entry,
 431  * accounting for the size of the entries.
 432  */
 433
 434 #define OLD_SECTION_H(n) \
 435      (*(Elf32_Shdr *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
 436 #define NEW_SECTION_H(n) \
 437      (*(Elf32_Shdr *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
 438 #define OLD_PROGRAM_H(n) \
 439      (*(Elf32_Phdr *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
 440 #define NEW_PROGRAM_H(n) \
 441      (*(Elf32_Phdr *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
 442
 443 #define PATCH_INDEX(n) \
 444   do { \
 445          if ((n) >= old_bss_index) \
 446            (n)++; } while (0)
 447 typedef unsigned char byte;
 448
 449 /* Round X up to a multiple of Y.  */
 450
 451 int
 452 round_up (x, y)
 453      int x, y;
 454 {
 455   int rem = x % y;
 456   if (rem == 0)
 457     return x;
 458   return x - rem + y;
 459 }
 460
 461 /* Return the index of the section named NAME.
 462    SECTION_NAMES, FILE_NAME and FILE_H give information
 463    about the file we are looking in.
 464
 465    If we don't find the section NAME, that is a fatal error
 466    if NOERROR is 0; we return -1 if NOERROR is nonzero.  */
 467
 468 static int
 469 find_section (name, section_names, file_name, old_file_h, old_section_h, noerror)
 470      char *name;
 471      char *section_names;
 472      char *file_name;
 473      Elf32_Ehdr *old_file_h;
 474      Elf32_Shdr *old_section_h;
 475      int noerror;
 476 {
 477   int idx;
 478
 479   for (idx = 1; idx < old_file_h->e_shnum; idx++)
 480     {
 481 #ifdef DEBUG
 482       fprintf (stderr, "Looking for %s - found %s\n", name,
 483                section_names + OLD_SECTION_H (idx).sh_name);
 484 #endif
 485       if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
 486                    name))
 487         break;
 488     }
 489   if (idx == old_file_h->e_shnum)
 490     {
 491       if (noerror)
 492         return -1;
 493       else
 494         fatal ("Can't find .bss in %s.\n", file_name, 0);
 495     }
 496
 497   return idx;
 498 }
 499
 500 /* ****************************************************************
 501  * unexec
 502  *
 503  * driving logic.
 504  *
 505  * In ELF, this works by replacing the old .bss section with a new
 506  * .data section, and inserting an empty .bss immediately afterwards.
 507  *
 508  */
 509 void
 510 unexec (new_name, old_name, data_start, bss_start, entry_address)
 511      char *new_name, *old_name;
 512      unsigned data_start, bss_start, entry_address;
 513 {
 514   extern unsigned int bss_end;
 515   int new_file, old_file, new_file_size;
 516
 517   /* Pointers to the base of the image of the two files.  */
 518   caddr_t old_base, new_base;
 519
 520   /* Pointers to the file, program and section headers for the old and new
 521      files.  */
 522   Elf32_Ehdr *old_file_h, *new_file_h;
 523   Elf32_Phdr *old_program_h, *new_program_h;
 524   Elf32_Shdr *old_section_h, *new_section_h;
 525
 526   /* Point to the section name table in the old file.  */
 527   char *old_section_names;
 528
 529   Elf32_Addr old_bss_addr, new_bss_addr;
 530   Elf32_Word old_bss_size, new_data2_size;
 531   Elf32_Off  new_data2_offset;
 532   Elf32_Addr new_data2_addr;
 533   Elf32_Addr new_offsets_shift;
 534
 535   int n, nn, old_bss_index, old_data_index, new_data2_index;
 536   int old_mdebug_index;
 537   struct stat stat_buf;
 538
 539   /* Open the old file & map it into the address space.  */
 540
 541   old_file = open (old_name, O_RDONLY);
 542
 543   if (old_file < 0)
 544     fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
 545
 546   if (fstat (old_file, &stat_buf) == -1)
 547     fatal ("Can't fstat(%s): errno %d\n", old_name, errno);
 548
 549   old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0);
 550
 551   if (old_base == (caddr_t) -1)
 552     fatal ("Can't mmap(%s): errno %d\n", old_name, errno);
 553
 554 #ifdef DEBUG
 555   fprintf (stderr, "mmap(%s, %x) -> %x\n", old_name, stat_buf.st_size,
 556            old_base);
 557 #endif
 558
 559   /* Get pointers to headers & section names.  */
 560
 561   old_file_h = (Elf32_Ehdr *) old_base;
 562   old_program_h = (Elf32_Phdr *) ((byte *) old_base + old_file_h->e_phoff);
 563   old_section_h = (Elf32_Shdr *) ((byte *) old_base + old_file_h->e_shoff);
 564   old_section_names
 565     = (char *) old_base + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
 566
 567   /* Find the mdebug section, if any.  */
 568
 569   old_mdebug_index = find_section (".mdebug", old_section_names,
 570                                    old_name, old_file_h, old_section_h, 1);
 571
 572   /* Find the old .bss section. */
 573
 574   old_bss_index = find_section (".bss", old_section_names,
 575                                 old_name, old_file_h, old_section_h, 0);
 576
 577   /* Find the old .data section.  Figure out parameters of
 578      the new data2 and bss sections.  */
 579
 580   old_data_index = find_section (".data", old_section_names,
 581                                  old_name, old_file_h, old_section_h, 0);
 582
 583   old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
 584   old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
 585 #if defined(emacs) || !defined(DEBUG)
 586   bss_end = (unsigned int) sbrk (0);
 587   new_bss_addr = (Elf32_Addr) bss_end;
 588 #else
 589   new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
 590 #endif
 591   new_data2_addr = old_bss_addr;
 592   new_data2_size = new_bss_addr - old_bss_addr;
 593   new_data2_offset  = OLD_SECTION_H (old_data_index).sh_offset +
 594     (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
 595   new_offsets_shift = new_bss_addr -
 596     ((old_bss_addr & ~0xfff) + ((old_bss_addr & 0xfff) ? 0x1000 : 0));
 597
 598 #ifdef DEBUG
 599   fprintf (stderr, "old_bss_index %d\n", old_bss_index);
 600   fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
 601   fprintf (stderr, "old_bss_size %x\n", old_bss_size);
 602   fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
 603   fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
 604   fprintf (stderr, "new_data2_size %x\n", new_data2_size);
 605   fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
 606   fprintf (stderr, "new_offsets_shift %x\n", new_offsets_shift);
 607 #endif
 608
 609   if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
 610     fatal (".bss shrank when undumping???\n", 0, 0);
 611
 612   /* Set the output file to the right size and mmap it.  Set
 613      pointers to various interesting objects.  stat_buf still has
 614      old_file data.  */
 615
 616   new_file = open (new_name, O_RDWR | O_CREAT, 0666);
 617   if (new_file < 0)
 618     fatal ("Can't creat (%s): errno %d\n", new_name, errno);
 619
 620   new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_offsets_shift;
 621
 622   if (ftruncate (new_file, new_file_size))
 623     fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
 624
 625   new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED,
 626                    new_file, 0);
 627
 628   if (new_base == (caddr_t) -1)
 629     fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
 630
 631   new_file_h = (Elf32_Ehdr *) new_base;
 632   new_program_h = (Elf32_Phdr *) ((byte *) new_base + old_file_h->e_phoff);
 633   new_section_h
 634     = (Elf32_Shdr *) ((byte *) new_base + old_file_h->e_shoff
 635                       + new_offsets_shift);
 636
 637   /* Make our new file, program and section headers as copies of the
 638      originals.  */
 639
 640   memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
 641   memcpy (new_program_h, old_program_h,
 642           old_file_h->e_phnum * old_file_h->e_phentsize);
 643
 644   /* Modify the e_shstrndx if necessary. */
 645   PATCH_INDEX (new_file_h->e_shstrndx);
 646
 647   /* Fix up file header.  We'll add one section.  Section header is
 648      further away now.  */
 649
 650   new_file_h->e_shoff += new_offsets_shift;
 651   new_file_h->e_shnum += 1;
 652
 653 #ifdef DEBUG
 654   fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
 655   fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
 656   fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
 657   fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
 658 #endif
 659
 660   /* Fix up a new program header.  Extend the writable data segment so
 661      that the bss area is covered too. Find that segment by looking
 662      for a segment that ends just before the .bss area.  Make sure
 663      that no segments are above the new .data2.  Put a loop at the end
 664      to adjust the offset and address of any segment that is above
 665      data2, just in case we decide to allow this later.  */
 666
 667   for (n = new_file_h->e_phnum - 1; n >= 0; n--)
 668     {
 669       /* Compute maximum of all requirements for alignment of section.  */
 670       int alignment = (NEW_PROGRAM_H (n)).p_align;
 671       if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
 672         alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
 673
 674       /* Supposedly this condition is okay for the SGI.  */
 675 #if 0
 676       if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr)
 677         fatal ("Program segment above .bss in %s\n", old_name, 0);
 678 #endif
 679
 680       if (NEW_PROGRAM_H (n).p_type == PT_LOAD
 681           && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
 682                         + (NEW_PROGRAM_H (n)).p_filesz,
 683                         alignment)
 684               == round_up (old_bss_addr, alignment)))
 685         break;
 686     }
 687   if (n < 0)
 688     fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
 689
 690   NEW_PROGRAM_H (n).p_filesz += new_offsets_shift;
 691   NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
 692
 693 #if 1                           /* Maybe allow section after data2 - does this ever happen?  */
 694   for (n = new_file_h->e_phnum - 1; n >= 0; n--)
 695     {
 696       if (NEW_PROGRAM_H (n).p_vaddr
 697           && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
 698         NEW_PROGRAM_H (n).p_vaddr += new_offsets_shift - old_bss_size;
 699
 700       if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
 701         NEW_PROGRAM_H (n).p_offset += new_offsets_shift;
 702     }
 703 #endif
 704
 705   /* Fix up section headers based on new .data2 section.  Any section
 706      whose offset or virtual address is after the new .data2 section
 707      gets its value adjusted.  .bss size becomes zero and new address
 708      is set.  data2 section header gets added by copying the existing
 709      .data header and modifying the offset, address and size.  */
 710   for (old_data_index = 1; old_data_index < old_file_h->e_shnum;
 711        old_data_index++)
 712     if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
 713                  ".data"))
 714       break;
 715   if (old_data_index == old_file_h->e_shnum)
 716     fatal ("Can't find .data in %s.\n", old_name, 0);
 717
 718   /* Walk through all section headers, insert the new data2 section right
 719      before the new bss section.  */
 720   for (n = 1, nn = 1; n < old_file_h->e_shnum; n++, nn++)
 721     {
 722       caddr_t src;
 723
 724       /* If it is bss section, insert the new data2 section before it.  */
 725       if (n == old_bss_index)
 726         {
 727           /* Steal the data section header for this data2 section.  */
 728           memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
 729                   new_file_h->e_shentsize);
 730
 731           NEW_SECTION_H (nn).sh_addr = new_data2_addr;
 732           NEW_SECTION_H (nn).sh_offset = new_data2_offset;
 733           NEW_SECTION_H (nn).sh_size = new_data2_size;
 734           /* Use the bss section's alignment. This will assure that the
 735              new data2 section always be placed in the same spot as the old
 736              bss section by any other application.  */
 737           NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
 738
 739           /* Now copy over what we have in the memory now.  */
 740           memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
 741                   (caddr_t) OLD_SECTION_H (n).sh_addr,
 742                   new_data2_size);
 743           nn++;
 744           memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
 745                   old_file_h->e_shentsize);
 746
 747           /* The new bss section's size is zero, and its file offset and virtual
 748              address should be off by NEW_OFFSETS_SHIFT.  */
 749           NEW_SECTION_H (nn).sh_offset += new_offsets_shift;
 750           NEW_SECTION_H (nn).sh_addr    = new_bss_addr;
 751           /* Let the new bss section address alignment be the same as the
 752              section address alignment followed the old bss section, so
 753              this section will be placed in exactly the same place.  */
 754           NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
 755           NEW_SECTION_H (nn).sh_size = 0;
 756         }
 757       else
 758         memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
 759                 old_file_h->e_shentsize);
 760
 761       /* Any section that was original placed AFTER the bss
 762          section must now be adjusted by NEW_OFFSETS_SHIFT.  */
 763
 764       if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
 765         NEW_SECTION_H (nn).sh_offset += new_offsets_shift;
 766
 767       /* If any section hdr refers to the section after the new .data
 768          section, make it refer to next one because we have inserted
 769          a new section in between.  */
 770
 771       PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
 772       /* For symbol tables, info is a symbol table index,
 773          so don't change it.  */
 774       if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
 775           && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
 776         PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
 777
 778       /* Now, start to copy the content of sections. */
 779       if (NEW_SECTION_H (nn).sh_type == SHT_NULL
 780           || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
 781         continue;
 782
 783       /* Write out the sections. .data and .data1 (and data2, called
 784          ".data" in the strings table) get copied from the current process
 785          instead of the old file.  */
 786       if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
 787           || !strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data1")
 788           || !strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".got"))
 789         src = (caddr_t) OLD_SECTION_H (n).sh_addr;
 790       else
 791         src = old_base + OLD_SECTION_H (n).sh_offset;
 792
 793       memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
 794               NEW_SECTION_H (nn).sh_size);
 795
 796       /* Adjust  the HDRR offsets in .mdebug and copy the
 797          line data if it's in its usual 'hole' in the object.
 798          Makes the new file debuggable with dbx.
 799          patches up two problems: the absolute file offsets
 800          in the HDRR record of .mdebug (see /usr/include/syms.h), and
 801          the ld bug that gets the line table in a hole in the
 802          elf file rather than in the .mdebug section proper.
 803          David Anderson. davea@sgi.com  Jan 16,1994.  */
 804       if (n == old_mdebug_index)
 805         {
 806 #define MDEBUGADJUST(__ct,__fileaddr)           \
 807   if (n_phdrr->__ct > 0)                        \
 808     {                                           \
 809       n_phdrr->__fileaddr += movement;          \
 810     }
 811
 812           HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset);
 813           HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset);
 814           unsigned movement = new_offsets_shift;
 815
 816           MDEBUGADJUST (idnMax, cbDnOffset);
 817           MDEBUGADJUST (ipdMax, cbPdOffset);
 818           MDEBUGADJUST (isymMax, cbSymOffset);
 819           MDEBUGADJUST (ioptMax, cbOptOffset);
 820           MDEBUGADJUST (iauxMax, cbAuxOffset);
 821           MDEBUGADJUST (issMax, cbSsOffset);
 822           MDEBUGADJUST (issExtMax, cbSsExtOffset);
 823           MDEBUGADJUST (ifdMax, cbFdOffset);
 824           MDEBUGADJUST (crfd, cbRfdOffset);
 825           MDEBUGADJUST (iextMax, cbExtOffset);
 826           /* The Line Section, being possible off in a hole of the object,
 827              requires special handling.  */
 828           if (n_phdrr->cbLine > 0)
 829             {
 830               if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset
 831                                            + OLD_SECTION_H (n).sh_size))
 832                 {
 833                   /* line data is in a hole in elf. do special copy and adjust
 834                      for this ld mistake.
 835                      */
 836                   n_phdrr->cbLineOffset += movement;
 837
 838                   memcpy (n_phdrr->cbLineOffset + new_base,
 839                           o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
 840                 }
 841               else
 842                 {
 843                   /* somehow line data is in .mdebug as it is supposed to be.  */
 844                   MDEBUGADJUST (cbLine, cbLineOffset);
 845                 }
 846             }
 847         }
 848
 849       /* If it is the symbol table, its st_shndx field needs to be patched. */
 850       if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
 851           || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
 852         {
 853           Elf32_Shdr *spt = &NEW_SECTION_H (nn);
 854           unsigned int num = spt->sh_size / spt->sh_entsize;
 855           Elf32_Sym * sym = (Elf32_Sym *) (NEW_SECTION_H (nn).sh_offset
 856                                            + new_base);
 857           for (; num--; sym++)
 858             {
 859               if (sym->st_shndx == SHN_UNDEF
 860                   || sym->st_shndx == SHN_ABS
 861                   || sym->st_shndx == SHN_COMMON)
 862                 continue;
 863
 864               PATCH_INDEX (sym->st_shndx);
 865             }
 866         }
 867     }
 868
 869   /* Close the files and make the new file executable.  */
 870
 871   if (close (old_file))
 872     fatal ("Can't close (%s): errno %d\n", old_name, errno);
 873
 874   if (close (new_file))
 875     fatal ("Can't close (%s): errno %d\n", new_name, errno);
 876
 877   if (stat (new_name, &stat_buf) == -1)
 878     fatal ("Can't stat (%s): errno %d\n", new_name, errno);
 879
 880   n = umask (777);
 881   umask (n);
 882   stat_buf.st_mode |= 0111 & ~n;
 883   if (chmod (new_name, stat_buf.st_mode) == -1)
 884     fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
 885 }