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1 /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992, 1999, 2000, 2001,
2 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4
5 This file is part of GNU Emacs.
6
7 GNU Emacs 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 GNU Emacs 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 GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
19
20 /*
21 In other words, you are welcome to use, share and improve this program.
22 You are forbidden to forbid anyone else to use, share and improve
23 what you give them. Help stamp out software-hoarding! */
24
25
26 /*
27 * unexec.c - Convert a running program into an a.out file.
28 *
29 * Author: Spencer W. Thomas
30 * Computer Science Dept.
31 * University of Utah
32 * Date: Tue Mar 2 1982
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 old_name is non-NULL, the symbol table will be taken from the given file.
41 * On some machines, an existing old_name file is required.
42 *
43 */
44
45 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
46 * ELF support added.
47 *
48 * Basic theory: the data space of the running process needs to be
49 * dumped to the output file. Normally we would just enlarge the size
50 * of .data, scooting everything down. But we can't do that in ELF,
51 * because there is often something between the .data space and the
52 * .bss space.
53 *
54 * In the temacs dump below, notice that the Global Offset Table
55 * (.got) and the Dynamic link data (.dynamic) come between .data1 and
56 * .bss. It does not work to overlap .data with these fields.
57 *
58 * The solution is to create a new .data segment. This segment is
59 * filled with data from the current process. Since the contents of
60 * various sections refer to sections by index, the new .data segment
61 * is made the last in the table to avoid changing any existing index.
62
63 * This is an example of how the section headers are changed. "Addr"
64 * is a process virtual address. "Offset" is a file offset.
65
66 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
67
68 temacs:
69
70 **** SECTION HEADER TABLE ****
71 [No] Type Flags Addr Offset Size Name
72 Link Info Adralgn Entsize
73
74 [1] 1 2 0x80480d4 0xd4 0x13 .interp
75 0 0 0x1 0
76
77 [2] 5 2 0x80480e8 0xe8 0x388 .hash
78 3 0 0x4 0x4
79
80 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
81 4 1 0x4 0x10
82
83 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
84 0 0 0x1 0
85
86 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
87 3 7 0x4 0x8
88
89 [6] 1 6 0x8049348 0x1348 0x3 .init
90 0 0 0x4 0
91
92 [7] 1 6 0x804934c 0x134c 0x680 .plt
93 0 0 0x4 0x4
94
95 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
96 0 0 0x4 0
97
98 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
99 0 0 0x4 0
100
101 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
102 0 0 0x4 0
103
104 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
105 0 0 0x4 0
106
107 [12] 1 3 0x8088330 0x3f330 0x20afc .data
108 0 0 0x4 0
109
110 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
111 0 0 0x4 0
112
113 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
114 0 0 0x4 0x4
115
116 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
117 4 0 0x4 0x8
118
119 [16] 8 3 0x80a98f4 0x608f4 0x449c .bss
120 0 0 0x4 0
121
122 [17] 2 0 0 0x608f4 0x9b90 .symtab
123 18 371 0x4 0x10
124
125 [18] 3 0 0 0x6a484 0x8526 .strtab
126 0 0 0x1 0
127
128 [19] 3 0 0 0x729aa 0x93 .shstrtab
129 0 0 0x1 0
130
131 [20] 1 0 0 0x72a3d 0x68b7 .comment
132 0 0 0x1 0
133
134 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
135
136 xemacs:
137
138 **** SECTION HEADER TABLE ****
139 [No] Type Flags Addr Offset Size Name
140 Link Info Adralgn Entsize
141
142 [1] 1 2 0x80480d4 0xd4 0x13 .interp
143 0 0 0x1 0
144
145 [2] 5 2 0x80480e8 0xe8 0x388 .hash
146 3 0 0x4 0x4
147
148 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
149 4 1 0x4 0x10
150
151 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
152 0 0 0x1 0
153
154 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
155 3 7 0x4 0x8
156
157 [6] 1 6 0x8049348 0x1348 0x3 .init
158 0 0 0x4 0
159
160 [7] 1 6 0x804934c 0x134c 0x680 .plt
161 0 0 0x4 0x4
162
163 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
164 0 0 0x4 0
165
166 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
167 0 0 0x4 0
168
169 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
170 0 0 0x4 0
171
172 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
173 0 0 0x4 0
174
175 [12] 1 3 0x8088330 0x3f330 0x20afc .data
176 0 0 0x4 0
177
178 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
179 0 0 0x4 0
180
181 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
182 0 0 0x4 0x4
183
184 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
185 4 0 0x4 0x8
186
187 [16] 8 3 0x80c6800 0x7d800 0 .bss
188 0 0 0x4 0
189
190 [17] 2 0 0 0x7d800 0x9b90 .symtab
191 18 371 0x4 0x10
192
193 [18] 3 0 0 0x87390 0x8526 .strtab
194 0 0 0x1 0
195
196 [19] 3 0 0 0x8f8b6 0x93 .shstrtab
197 0 0 0x1 0
198
199 [20] 1 0 0 0x8f949 0x68b7 .comment
200 0 0 0x1 0
201
202 [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
203 0 0 0x4 0
204
205 * This is an example of how the file header is changed. "Shoff" is
206 * the section header offset within the file. Since that table is
207 * after the new .data section, it is moved. "Shnum" is the number of
208 * sections, which we increment.
209 *
210 * "Phoff" is the file offset to the program header. "Phentsize" and
211 * "Shentsz" are the program and section header entries sizes respectively.
212 * These can be larger than the apparent struct sizes.
213
214 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
215
216 temacs:
217
218 **** ELF HEADER ****
219 Class Data Type Machine Version
220 Entry Phoff Shoff Flags Ehsize
221 Phentsize Phnum Shentsz Shnum Shstrndx
222
223 1 1 2 3 1
224 0x80499cc 0x34 0x792f4 0 0x34
225 0x20 5 0x28 21 19
226
227 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
228
229 xemacs:
230
231 **** ELF HEADER ****
232 Class Data Type Machine Version
233 Entry Phoff Shoff Flags Ehsize
234 Phentsize Phnum Shentsz Shnum Shstrndx
235
236 1 1 2 3 1
237 0x80499cc 0x34 0x96200 0 0x34
238 0x20 5 0x28 22 19
239
240 * These are the program headers. "Offset" is the file offset to the
241 * segment. "Vaddr" is the memory load address. "Filesz" is the
242 * segment size as it appears in the file, and "Memsz" is the size in
243 * memory. Below, the third segment is the code and the fourth is the
244 * data: the difference between Filesz and Memsz is .bss
245
246 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
247
248 temacs:
249 ***** PROGRAM EXECUTION HEADER *****
250 Type Offset Vaddr Paddr
251 Filesz Memsz Flags Align
252
253 6 0x34 0x8048034 0
254 0xa0 0xa0 5 0
255
256 3 0xd4 0 0
257 0x13 0 4 0
258
259 1 0x34 0x8048034 0
260 0x3f2f9 0x3f2f9 5 0x1000
261
262 1 0x3f330 0x8088330 0
263 0x215c4 0x25a60 7 0x1000
264
265 2 0x60874 0x80a9874 0
266 0x80 0 7 0
267
268 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
269
270 xemacs:
271 ***** PROGRAM EXECUTION HEADER *****
272 Type Offset Vaddr Paddr
273 Filesz Memsz Flags Align
274
275 6 0x34 0x8048034 0
276 0xa0 0xa0 5 0
277
278 3 0xd4 0 0
279 0x13 0 4 0
280
281 1 0x34 0x8048034 0
282 0x3f2f9 0x3f2f9 5 0x1000
283
284 1 0x3f330 0x8088330 0
285 0x3e4d0 0x3e4d0 7 0x1000
286
287 2 0x60874 0x80a9874 0
288 0x80 0 7 0
289
290
291 */
292 \f
293 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
294 *
295 * The above mechanism does not work if the unexeced ELF file is being
296 * re-layout by other applications (such as `strip'). All the applications
297 * that re-layout the internal of ELF will layout all sections in ascending
298 * order of their file offsets. After the re-layout, the data2 section will
299 * still be the LAST section in the section header vector, but its file offset
300 * is now being pushed far away down, and causes part of it not to be mapped
301 * in (ie. not covered by the load segment entry in PHDR vector), therefore
302 * causes the new binary to fail.
303 *
304 * The solution is to modify the unexec algorithm to insert the new data2
305 * section header right before the new bss section header, so their file
306 * offsets will be in the ascending order. Since some of the section's (all
307 * sections AFTER the bss section) indexes are now changed, we also need to
308 * modify some fields to make them point to the right sections. This is done
309 * by macro PATCH_INDEX. All the fields that need to be patched are:
310 *
311 * 1. ELF header e_shstrndx field.
312 * 2. section header sh_link and sh_info field.
313 * 3. symbol table entry st_shndx field.
314 *
315 * The above example now should look like:
316
317 **** SECTION HEADER TABLE ****
318 [No] Type Flags Addr Offset Size Name
319 Link Info Adralgn Entsize
320
321 [1] 1 2 0x80480d4 0xd4 0x13 .interp
322 0 0 0x1 0
323
324 [2] 5 2 0x80480e8 0xe8 0x388 .hash
325 3 0 0x4 0x4
326
327 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
328 4 1 0x4 0x10
329
330 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
331 0 0 0x1 0
332
333 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
334 3 7 0x4 0x8
335
336 [6] 1 6 0x8049348 0x1348 0x3 .init
337 0 0 0x4 0
338
339 [7] 1 6 0x804934c 0x134c 0x680 .plt
340 0 0 0x4 0x4
341
342 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
343 0 0 0x4 0
344
345 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
346 0 0 0x4 0
347
348 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
349 0 0 0x4 0
350
351 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
352 0 0 0x4 0
353
354 [12] 1 3 0x8088330 0x3f330 0x20afc .data
355 0 0 0x4 0
356
357 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
358 0 0 0x4 0
359
360 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
361 0 0 0x4 0x4
362
363 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
364 4 0 0x4 0x8
365
366 [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
367 0 0 0x4 0
368
369 [17] 8 3 0x80c6800 0x7d800 0 .bss
370 0 0 0x4 0
371
372 [18] 2 0 0 0x7d800 0x9b90 .symtab
373 19 371 0x4 0x10
374
375 [19] 3 0 0 0x87390 0x8526 .strtab
376 0 0 0x1 0
377
378 [20] 3 0 0 0x8f8b6 0x93 .shstrtab
379 0 0 0x1 0
380
381 [21] 1 0 0 0x8f949 0x68b7 .comment
382 0 0 0x1 0
383
384 */
385 \f
386 /* We do not use mmap because that fails with NFS.
387 Instead we read the whole file, modify it, and write it out. */
388
389 #include <config.h>
390 extern void fatal (const char *msgid, ...);
391
392 #include <sys/types.h>
393 #include <stdio.h>
394 #include <sys/stat.h>
395 #include <memory.h>
396 #include <errno.h>
397 #include <unistd.h>
398 #include <fcntl.h>
399 #if !defined (__NetBSD__) && !defined (__OpenBSD__)
400 #include <elf.h>
401 #endif /* not __NetBSD__ and not __OpenBSD__ */
402 #include <sys/mman.h>
403 #if defined (_SYSTYPE_SYSV)
404 #include <sys/elf_mips.h>
405 #include <sym.h>
406 #endif /* _SYSTYPE_SYSV */
407 #if __sgi
408 #include <syms.h> /* for HDRR declaration */
409 #endif /* __sgi */
410
411 #ifndef MAP_ANON
412 #ifdef MAP_ANONYMOUS
413 #define MAP_ANON MAP_ANONYMOUS
414 #else
415 #define MAP_ANON 0
416 #endif
417 #endif
418
419 #ifndef MAP_FAILED
420 #define MAP_FAILED ((void *) -1)
421 #endif
422
423 #if defined (__alpha__) && !defined (__NetBSD__) && !defined (__OpenBSD__)
424 /* Declare COFF debugging symbol table. This used to be in
425 /usr/include/sym.h, but this file is no longer included in Red Hat
426 5.0 and presumably in any other glibc 2.x based distribution. */
427 typedef struct {
428 short magic;
429 short vstamp;
430 int ilineMax;
431 int idnMax;
432 int ipdMax;
433 int isymMax;
434 int ioptMax;
435 int iauxMax;
436 int issMax;
437 int issExtMax;
438 int ifdMax;
439 int crfd;
440 int iextMax;
441 long cbLine;
442 long cbLineOffset;
443 long cbDnOffset;
444 long cbPdOffset;
445 long cbSymOffset;
446 long cbOptOffset;
447 long cbAuxOffset;
448 long cbSsOffset;
449 long cbSsExtOffset;
450 long cbFdOffset;
451 long cbRfdOffset;
452 long cbExtOffset;
453 } HDRR, *pHDRR;
454 #define cbHDRR sizeof(HDRR)
455 #define hdrNil ((pHDRR)0)
456 #endif
457
458 #ifdef __NetBSD__
459 /*
460 * NetBSD does not have normal-looking user-land ELF support.
461 */
462 # if defined __alpha__ || defined __sparc_v9__
463 # define ELFSIZE 64
464 # else
465 # define ELFSIZE 32
466 # endif
467 # include <sys/exec_elf.h>
468
469 # ifndef PT_LOAD
470 # define PT_LOAD Elf_pt_load
471 # if 0 /* was in pkgsrc patches for 20.7 */
472 # define SHT_PROGBITS Elf_sht_progbits
473 # endif
474 # define SHT_SYMTAB Elf_sht_symtab
475 # define SHT_DYNSYM Elf_sht_dynsym
476 # define SHT_NULL Elf_sht_null
477 # define SHT_NOBITS Elf_sht_nobits
478 # define SHT_REL Elf_sht_rel
479 # define SHT_RELA Elf_sht_rela
480
481 # define SHN_UNDEF Elf_eshn_undefined
482 # define SHN_ABS Elf_eshn_absolute
483 # define SHN_COMMON Elf_eshn_common
484 # endif /* !PT_LOAD */
485
486 # ifdef __alpha__
487 # include <sys/exec_ecoff.h>
488 # define HDRR struct ecoff_symhdr
489 # define pHDRR HDRR *
490 # endif /* __alpha__ */
491
492 #ifdef __mips__ /* was in pkgsrc patches for 20.7 */
493 # define SHT_MIPS_DEBUG DT_MIPS_FLAGS
494 # define HDRR struct Elf_Shdr
495 #endif /* __mips__ */
496 #endif /* __NetBSD__ */
497
498 #ifdef __OpenBSD__
499 # include <sys/exec_elf.h>
500 #endif
501
502 #if __GNU_LIBRARY__ - 0 >= 6
503 # include <link.h> /* get ElfW etc */
504 #endif
505
506 #ifndef ElfW
507 # ifdef __STDC__
508 # define ElfBitsW(bits, type) Elf##bits##_##type
509 # else
510 # define ElfBitsW(bits, type) Elf/**/bits/**/_/**/type
511 # endif
512 # ifdef _LP64
513 # define ELFSIZE 64
514 # else
515 # define ELFSIZE 32
516 # endif
517 /* This macro expands `bits' before invoking ElfBitsW. */
518 # define ElfExpandBitsW(bits, type) ElfBitsW (bits, type)
519 # define ElfW(type) ElfExpandBitsW (ELFSIZE, type)
520 #endif
521
522 #ifndef ELF_BSS_SECTION_NAME
523 #define ELF_BSS_SECTION_NAME ".bss"
524 #endif
525
526 /* Get the address of a particular section or program header entry,
527 * accounting for the size of the entries.
528 */
529 /*
530 On PPC Reference Platform running Solaris 2.5.1
531 the plt section is also of type NOBI like the bss section.
532 (not really stored) and therefore sections after the bss
533 section start at the plt offset. The plt section is always
534 the one just before the bss section.
535 Thus, we modify the test from
536 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
537 to
538 if (NEW_SECTION_H (nn).sh_offset >=
539 OLD_SECTION_H (old_bss_index-1).sh_offset)
540 This is just a hack. We should put the new data section
541 before the .plt section.
542 And we should not have this routine at all but use
543 the libelf library to read the old file and create the new
544 file.
545 The changed code is minimal and depends on prep set in m/prep.h
546 Erik Deumens
547 Quantum Theory Project
548 University of Florida
549 deumens@qtp.ufl.edu
550 Apr 23, 1996
551 */
552
553 #define OLD_SECTION_H(n) \
554 (*(ElfW(Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
555 #define NEW_SECTION_H(n) \
556 (*(ElfW(Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
557 #define OLD_PROGRAM_H(n) \
558 (*(ElfW(Phdr) *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
559 #define NEW_PROGRAM_H(n) \
560 (*(ElfW(Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
561
562 #define PATCH_INDEX(n) \
563 do { \
564 if ((int) (n) >= old_bss_index) \
565 (n)++; } while (0)
566 typedef unsigned char byte;
567
568 /* Round X up to a multiple of Y. */
569
570 static ElfW(Addr)
571 round_up (ElfW(Addr) x, ElfW(Addr) y)
572 {
573 int rem = x % y;
574 if (rem == 0)
575 return x;
576 return x - rem + y;
577 }
578
579 /* Return the index of the section named NAME.
580 SECTION_NAMES, FILE_NAME and FILE_H give information
581 about the file we are looking in.
582
583 If we don't find the section NAME, that is a fatal error
584 if NOERROR is 0; we return -1 if NOERROR is nonzero. */
585
586 static int
587 find_section (const char *name, const char *section_names, const char *file_name,
588 ElfW(Ehdr) *old_file_h, ElfW(Shdr) *old_section_h, int noerror)
589 {
590 int idx;
591
592 for (idx = 1; idx < old_file_h->e_shnum; idx++)
593 {
594 #ifdef DEBUG
595 fprintf (stderr, "Looking for %s - found %s\n", name,
596 section_names + OLD_SECTION_H (idx).sh_name);
597 #endif
598 if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
599 name))
600 break;
601 }
602 if (idx == old_file_h->e_shnum)
603 {
604 if (noerror)
605 return -1;
606 else
607 fatal ("Can't find %s in %s.\n", name, file_name);
608 }
609
610 return idx;
611 }
612
613 /* ****************************************************************
614 * unexec
615 *
616 * driving logic.
617 *
618 * In ELF, this works by replacing the old .bss section with a new
619 * .data section, and inserting an empty .bss immediately afterwards.
620 *
621 */
622 void
623 unexec (const char *new_name, const char *old_name)
624 {
625 int new_file, old_file, new_file_size;
626
627 /* Pointers to the base of the image of the two files. */
628 caddr_t old_base, new_base;
629
630 #if MAP_ANON == 0
631 int mmap_fd;
632 #else
633 # define mmap_fd -1
634 #endif
635
636 /* Pointers to the file, program and section headers for the old and
637 new files. */
638 ElfW(Ehdr) *old_file_h, *new_file_h;
639 ElfW(Phdr) *old_program_h, *new_program_h;
640 ElfW(Shdr) *old_section_h, *new_section_h;
641
642 /* Point to the section name table in the old file. */
643 char *old_section_names;
644
645 ElfW(Addr) old_bss_addr, new_bss_addr;
646 ElfW(Word) old_bss_size, new_data2_size;
647 ElfW(Off) new_data2_offset;
648 ElfW(Addr) new_data2_addr;
649 ElfW(Off) old_bss_offset;
650 ElfW(Word) new_data2_incr;
651
652 int n, nn;
653 int old_bss_index, old_sbss_index, old_plt_index;
654 int old_data_index, new_data2_index;
655 int old_mdebug_index;
656 struct stat stat_buf;
657 int old_file_size;
658
659 /* Open the old file, allocate a buffer of the right size, and read
660 in the file contents. */
661
662 old_file = open (old_name, O_RDONLY);
663
664 if (old_file < 0)
665 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
666
667 if (fstat (old_file, &stat_buf) == -1)
668 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
669
670 #if MAP_ANON == 0
671 mmap_fd = open ("/dev/zero", O_RDONLY);
672 if (mmap_fd < 0)
673 fatal ("Can't open /dev/zero for reading: errno %d\n", errno, 0);
674 #endif
675
676 /* We cannot use malloc here because that may use sbrk. If it does,
677 we'd dump our temporary buffers with Emacs, and we'd have to be
678 extra careful to use the correct value of sbrk(0) after
679 allocating all buffers in the code below, which we aren't. */
680 old_file_size = stat_buf.st_size;
681 old_base = mmap (NULL, old_file_size, PROT_READ | PROT_WRITE,
682 MAP_ANON | MAP_PRIVATE, mmap_fd, 0);
683 if (old_base == MAP_FAILED)
684 fatal ("Can't allocate buffer for %s\n", old_name, 0);
685
686 if (read (old_file, old_base, stat_buf.st_size) != stat_buf.st_size)
687 fatal ("Didn't read all of %s: errno %d\n", old_name, errno);
688
689 /* Get pointers to headers & section names */
690
691 old_file_h = (ElfW(Ehdr) *) old_base;
692 old_program_h = (ElfW(Phdr) *) ((byte *) old_base + old_file_h->e_phoff);
693 old_section_h = (ElfW(Shdr) *) ((byte *) old_base + old_file_h->e_shoff);
694 old_section_names = (char *) old_base
695 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
696
697 /* Find the mdebug section, if any. */
698
699 old_mdebug_index = find_section (".mdebug", old_section_names,
700 old_name, old_file_h, old_section_h, 1);
701
702 /* Find the old .bss section. Figure out parameters of the new
703 data2 and bss sections. */
704
705 old_bss_index = find_section (".bss", old_section_names,
706 old_name, old_file_h, old_section_h, 0);
707
708 old_sbss_index = find_section (".sbss", old_section_names,
709 old_name, old_file_h, old_section_h, 1);
710 if (old_sbss_index != -1)
711 if (OLD_SECTION_H (old_sbss_index).sh_type != SHT_NOBITS)
712 old_sbss_index = -1;
713
714 /* PowerPC64 has .plt in the BSS section. */
715 old_plt_index = find_section (".plt", old_section_names,
716 old_name, old_file_h, old_section_h, 1);
717 if (old_plt_index != -1)
718 if (OLD_SECTION_H (old_plt_index).sh_type != SHT_NOBITS)
719 old_plt_index = -1;
720
721 if (old_sbss_index == -1 && old_plt_index == -1)
722 {
723 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
724 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
725 old_bss_offset = OLD_SECTION_H (old_bss_index).sh_offset;
726 new_data2_index = old_bss_index;
727 }
728 else if (old_plt_index != -1
729 && (old_sbss_index == -1
730 || (OLD_SECTION_H (old_sbss_index).sh_addr
731 > OLD_SECTION_H (old_plt_index).sh_addr)))
732 {
733 old_bss_addr = OLD_SECTION_H (old_plt_index).sh_addr;
734 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size
735 + OLD_SECTION_H (old_plt_index).sh_size;
736 if (old_sbss_index != -1)
737 old_bss_size += OLD_SECTION_H (old_sbss_index).sh_size;
738 old_bss_offset = OLD_SECTION_H (old_plt_index).sh_offset;
739 new_data2_index = old_plt_index;
740 }
741 else
742 {
743 old_bss_addr = OLD_SECTION_H (old_sbss_index).sh_addr;
744 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size
745 + OLD_SECTION_H (old_sbss_index).sh_size;
746 old_bss_offset = OLD_SECTION_H (old_sbss_index).sh_offset;
747 new_data2_index = old_sbss_index;
748 }
749
750 /* Find the old .data section. Figure out parameters of
751 the new data2 and bss sections. */
752
753 old_data_index = find_section (".data", old_section_names,
754 old_name, old_file_h, old_section_h, 0);
755
756 #if defined (emacs) || !defined (DEBUG)
757 new_bss_addr = (ElfW(Addr)) sbrk (0);
758 #else
759 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
760 #endif
761 new_data2_addr = old_bss_addr;
762 new_data2_size = new_bss_addr - old_bss_addr;
763 new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset
764 + (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
765 /* This is the amount by which the sections following the bss sections
766 must be shifted in the image. It can differ from new_data2_size if
767 the end of the old .data section (and thus the offset of the .bss
768 section) was unaligned. */
769 new_data2_incr = new_data2_size + (new_data2_offset - old_bss_offset);
770
771 #ifdef DEBUG
772 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
773 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
774 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
775 fprintf (stderr, "old_bss_offset %x\n", old_bss_offset);
776 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
777 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
778 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
779 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
780 fprintf (stderr, "new_data2_incr %x\n", new_data2_incr);
781 #endif
782
783 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
784 fatal (".bss shrank when undumping???\n", 0, 0);
785
786 /* Set the output file to the right size. Allocate a buffer to hold
787 the image of the new file. Set pointers to various interesting
788 objects. stat_buf still has old_file data. */
789
790 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
791 if (new_file < 0)
792 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
793
794 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_incr;
795
796 if (ftruncate (new_file, new_file_size))
797 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
798
799 new_base = mmap (NULL, new_file_size, PROT_READ | PROT_WRITE,
800 MAP_ANON | MAP_PRIVATE, mmap_fd, 0);
801 if (new_base == MAP_FAILED)
802 fatal ("Can't allocate buffer for %s\n", old_name, 0);
803
804 new_file_h = (ElfW(Ehdr) *) new_base;
805 new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
806 new_section_h = (ElfW(Shdr) *)
807 ((byte *) new_base + old_file_h->e_shoff + new_data2_incr);
808
809 /* Make our new file, program and section headers as copies of the
810 originals. */
811
812 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
813 memcpy (new_program_h, old_program_h,
814 old_file_h->e_phnum * old_file_h->e_phentsize);
815
816 /* Modify the e_shstrndx if necessary. */
817 PATCH_INDEX (new_file_h->e_shstrndx);
818
819 /* Fix up file header. We'll add one section. Section header is
820 further away now. */
821
822 new_file_h->e_shoff += new_data2_incr;
823 new_file_h->e_shnum += 1;
824
825 #ifdef DEBUG
826 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
827 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
828 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
829 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
830 #endif
831
832 /* Fix up a new program header. Extend the writable data segment so
833 that the bss area is covered too. Find that segment by looking
834 for a segment that ends just before the .bss area. Make sure
835 that no segments are above the new .data2. Put a loop at the end
836 to adjust the offset and address of any segment that is above
837 data2, just in case we decide to allow this later. */
838
839 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
840 {
841 /* Compute maximum of all requirements for alignment of section. */
842 ElfW(Word) alignment = (NEW_PROGRAM_H (n)).p_align;
843 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
844 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
845
846 #ifdef __sgi
847 /* According to r02kar@x4u2.desy.de (Karsten Kuenne)
848 and oliva@gnu.org (Alexandre Oliva), on IRIX 5.2, we
849 always get "Program segment above .bss" when dumping
850 when the executable doesn't have an sbss section. */
851 if (old_sbss_index != -1)
852 #endif /* __sgi */
853 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz
854 > (old_sbss_index == -1
855 ? old_bss_addr
856 : round_up (old_bss_addr, alignment)))
857 fatal ("Program segment above .bss in %s\n", old_name, 0);
858
859 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
860 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
861 + (NEW_PROGRAM_H (n)).p_filesz,
862 alignment)
863 == round_up (old_bss_addr, alignment)))
864 break;
865 }
866 if (n < 0)
867 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
868
869 /* Make sure that the size includes any padding before the old .bss
870 section. */
871 NEW_PROGRAM_H (n).p_filesz = new_bss_addr - NEW_PROGRAM_H (n).p_vaddr;
872 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
873
874 #if 0 /* Maybe allow section after data2 - does this ever happen? */
875 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
876 {
877 if (NEW_PROGRAM_H (n).p_vaddr
878 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
879 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
880
881 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
882 NEW_PROGRAM_H (n).p_offset += new_data2_incr;
883 }
884 #endif
885
886 /* Fix up section headers based on new .data2 section. Any section
887 whose offset or virtual address is after the new .data2 section
888 gets its value adjusted. .bss size becomes zero and new address
889 is set. data2 section header gets added by copying the existing
890 .data header and modifying the offset, address and size. */
891
892 /* Walk through all section headers, insert the new data2 section right
893 before the new bss section. */
894 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
895 {
896 caddr_t src;
897 /* If it is (s)bss section, insert the new data2 section before it. */
898 /* new_data2_index is the index of either old_sbss or old_bss, that was
899 chosen as a section for new_data2. */
900 if (n == new_data2_index)
901 {
902 /* Steal the data section header for this data2 section. */
903 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
904 new_file_h->e_shentsize);
905
906 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
907 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
908 NEW_SECTION_H (nn).sh_size = new_data2_size;
909 /* Use the bss section's alignment. This will assure that the
910 new data2 section always be placed in the same spot as the old
911 bss section by any other application. */
912 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
913
914 /* Now copy over what we have in the memory now. */
915 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
916 (caddr_t) OLD_SECTION_H (n).sh_addr,
917 new_data2_size);
918 nn++;
919 }
920
921 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
922 old_file_h->e_shentsize);
923
924 if (n == old_bss_index
925 /* The new bss and sbss section's size is zero, and its file offset
926 and virtual address should be off by NEW_DATA2_SIZE. */
927 || n == old_sbss_index || n == old_plt_index
928 )
929 {
930 /* NN should be `old_s?bss_index + 1' at this point. */
931 NEW_SECTION_H (nn).sh_offset = new_data2_offset + new_data2_size;
932 NEW_SECTION_H (nn).sh_addr = new_data2_addr + new_data2_size;
933 /* Let the new bss section address alignment be the same as the
934 section address alignment followed the old bss section, so
935 this section will be placed in exactly the same place. */
936 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
937 NEW_SECTION_H (nn).sh_size = 0;
938 }
939 else
940 {
941 /* Any section that was originally placed after the .bss
942 section should now be off by NEW_DATA2_INCR. If a
943 section overlaps the .bss section, consider it to be
944 placed after the .bss section. Overlap can occur if the
945 section just before .bss has less-strict alignment; this
946 was observed between .symtab and .bss on Solaris 2.5.1
947 (sparc) with GCC snapshot 960602.
948
949 > dump -h temacs
950
951 temacs:
952
953 **** SECTION HEADER TABLE ****
954 [No] Type Flags Addr Offset Size Name
955 Link Info Adralgn Entsize
956
957 [22] 1 3 0x335150 0x315150 0x4 .data.rel.local
958 0 0 0x4 0
959
960 [23] 8 3 0x335158 0x315158 0x42720 .bss
961 0 0 0x8 0
962
963 [24] 2 0 0 0x315154 0x1c9d0 .symtab
964 25 1709 0x4 0x10
965 */
966
967 if (NEW_SECTION_H (nn).sh_offset >= old_bss_offset
968 || (NEW_SECTION_H (nn).sh_offset + NEW_SECTION_H (nn).sh_size
969 > new_data2_offset))
970 NEW_SECTION_H (nn).sh_offset += new_data2_incr;
971
972 /* Any section that was originally placed after the section
973 header table should now be off by the size of one section
974 header table entry. */
975 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
976 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
977 }
978
979 /* If any section hdr refers to the section after the new .data
980 section, make it refer to next one because we have inserted
981 a new section in between. */
982
983 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
984 /* For symbol tables, info is a symbol table index,
985 so don't change it. */
986 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
987 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
988 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
989
990 if (old_sbss_index != -1)
991 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".sbss"))
992 {
993 NEW_SECTION_H (nn).sh_offset =
994 round_up (NEW_SECTION_H (nn).sh_offset,
995 NEW_SECTION_H (nn).sh_addralign);
996 NEW_SECTION_H (nn).sh_type = SHT_PROGBITS;
997 }
998
999 /* Now, start to copy the content of sections. */
1000 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
1001 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
1002 continue;
1003
1004 /* Write out the sections. .data and .data1 (and data2, called
1005 ".data" in the strings table) get copied from the current process
1006 instead of the old file. */
1007 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
1008 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1009 ".sdata")
1010 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1011 ".lit4")
1012 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1013 ".lit8")
1014 /* The conditional bit below was in Oliva's original code
1015 (1999-08-25) and seems to have been dropped by mistake
1016 subsequently. It prevents a crash at startup under X in
1017 `IRIX64 6.5 6.5.17m', whether compiled on that relase or
1018 an earlier one. It causes no trouble on the other ELF
1019 platforms I could test (Irix 6.5.15m, Solaris 8, Debian
1020 Potato x86, Debian Woody SPARC); however, it's reported
1021 to cause crashes under some version of GNU/Linux. It's
1022 not yet clear what's changed in that Irix version to
1023 cause the problem, or why the fix sometimes fails under
1024 GNU/Linux. There's probably no good reason to have
1025 something Irix-specific here, but this will have to do
1026 for now. IRIX6_5 is the most specific macro we have to
1027 test. -- fx 2002-10-01
1028
1029 The issue _looks_ as though it's gone away on 6.5.18m,
1030 but maybe it's still lurking, to be triggered by some
1031 change in the binary. It appears to concern the dynamic
1032 loader, but I never got anywhere with an SGI support call
1033 seeking clues. -- fx 2002-11-29. */
1034 #ifdef IRIX6_5
1035 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1036 ".got")
1037 #endif
1038 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1039 ".sdata1")
1040 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1041 ".data1")
1042 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1043 ".sbss"))
1044 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
1045 else
1046 src = old_base + OLD_SECTION_H (n).sh_offset;
1047
1048 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
1049 NEW_SECTION_H (nn).sh_size);
1050
1051 #ifdef __alpha__
1052 /* Update Alpha COFF symbol table: */
1053 if (strcmp (old_section_names + OLD_SECTION_H (n).sh_name, ".mdebug")
1054 == 0)
1055 {
1056 pHDRR symhdr = (pHDRR) (NEW_SECTION_H (nn).sh_offset + new_base);
1057
1058 symhdr->cbLineOffset += new_data2_size;
1059 symhdr->cbDnOffset += new_data2_size;
1060 symhdr->cbPdOffset += new_data2_size;
1061 symhdr->cbSymOffset += new_data2_size;
1062 symhdr->cbOptOffset += new_data2_size;
1063 symhdr->cbAuxOffset += new_data2_size;
1064 symhdr->cbSsOffset += new_data2_size;
1065 symhdr->cbSsExtOffset += new_data2_size;
1066 symhdr->cbFdOffset += new_data2_size;
1067 symhdr->cbRfdOffset += new_data2_size;
1068 symhdr->cbExtOffset += new_data2_size;
1069 }
1070 #endif /* __alpha__ */
1071
1072 #if defined (_SYSTYPE_SYSV)
1073 if (NEW_SECTION_H (nn).sh_type == SHT_MIPS_DEBUG
1074 && old_mdebug_index != -1)
1075 {
1076 int diff = NEW_SECTION_H(nn).sh_offset
1077 - OLD_SECTION_H(old_mdebug_index).sh_offset;
1078 HDRR *phdr = (HDRR *)(NEW_SECTION_H (nn).sh_offset + new_base);
1079
1080 if (diff)
1081 {
1082 phdr->cbLineOffset += diff;
1083 phdr->cbDnOffset += diff;
1084 phdr->cbPdOffset += diff;
1085 phdr->cbSymOffset += diff;
1086 phdr->cbOptOffset += diff;
1087 phdr->cbAuxOffset += diff;
1088 phdr->cbSsOffset += diff;
1089 phdr->cbSsExtOffset += diff;
1090 phdr->cbFdOffset += diff;
1091 phdr->cbRfdOffset += diff;
1092 phdr->cbExtOffset += diff;
1093 }
1094 }
1095 #endif /* _SYSTYPE_SYSV */
1096
1097 #if __sgi
1098 /* Adjust the HDRR offsets in .mdebug and copy the
1099 line data if it's in its usual 'hole' in the object.
1100 Makes the new file debuggable with dbx.
1101 patches up two problems: the absolute file offsets
1102 in the HDRR record of .mdebug (see /usr/include/syms.h), and
1103 the ld bug that gets the line table in a hole in the
1104 elf file rather than in the .mdebug section proper.
1105 David Anderson. davea@sgi.com Jan 16,1994. */
1106 if (n == old_mdebug_index)
1107 {
1108 #define MDEBUGADJUST(__ct,__fileaddr) \
1109 if (n_phdrr->__ct > 0) \
1110 { \
1111 n_phdrr->__fileaddr += movement; \
1112 }
1113
1114 HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset);
1115 HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset);
1116 unsigned movement = new_data2_size;
1117
1118 MDEBUGADJUST (idnMax, cbDnOffset);
1119 MDEBUGADJUST (ipdMax, cbPdOffset);
1120 MDEBUGADJUST (isymMax, cbSymOffset);
1121 MDEBUGADJUST (ioptMax, cbOptOffset);
1122 MDEBUGADJUST (iauxMax, cbAuxOffset);
1123 MDEBUGADJUST (issMax, cbSsOffset);
1124 MDEBUGADJUST (issExtMax, cbSsExtOffset);
1125 MDEBUGADJUST (ifdMax, cbFdOffset);
1126 MDEBUGADJUST (crfd, cbRfdOffset);
1127 MDEBUGADJUST (iextMax, cbExtOffset);
1128 /* The Line Section, being possible off in a hole of the object,
1129 requires special handling. */
1130 if (n_phdrr->cbLine > 0)
1131 {
1132 if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset
1133 + OLD_SECTION_H (n).sh_size))
1134 {
1135 /* line data is in a hole in elf. do special copy and adjust
1136 for this ld mistake.
1137 */
1138 n_phdrr->cbLineOffset += movement;
1139
1140 memcpy (n_phdrr->cbLineOffset + new_base,
1141 o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
1142 }
1143 else
1144 {
1145 /* somehow line data is in .mdebug as it is supposed to be. */
1146 MDEBUGADJUST (cbLine, cbLineOffset);
1147 }
1148 }
1149 }
1150 #endif /* __sgi */
1151
1152 /* If it is the symbol table, its st_shndx field needs to be patched. */
1153 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
1154 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
1155 {
1156 ElfW(Shdr) *spt = &NEW_SECTION_H (nn);
1157 unsigned int num = spt->sh_size / spt->sh_entsize;
1158 ElfW(Sym) * sym = (ElfW(Sym) *) (NEW_SECTION_H (nn).sh_offset +
1159 new_base);
1160 for (; num--; sym++)
1161 {
1162 if ((sym->st_shndx == SHN_UNDEF)
1163 || (sym->st_shndx == SHN_ABS)
1164 || (sym->st_shndx == SHN_COMMON))
1165 continue;
1166
1167 PATCH_INDEX (sym->st_shndx);
1168 }
1169 }
1170 }
1171
1172 /* Update the symbol values of _edata and _end. */
1173 for (n = new_file_h->e_shnum - 1; n; n--)
1174 {
1175 byte *symnames;
1176 ElfW(Sym) *symp, *symendp;
1177
1178 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
1179 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
1180 continue;
1181
1182 symnames = ((byte *) new_base
1183 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
1184 symp = (ElfW(Sym) *) (NEW_SECTION_H (n).sh_offset + new_base);
1185 symendp = (ElfW(Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
1186
1187 for (; symp < symendp; symp ++)
1188 {
1189 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
1190 || strcmp ((char *) (symnames + symp->st_name), "end") == 0
1191 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0
1192 || strcmp ((char *) (symnames + symp->st_name), "edata") == 0)
1193 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
1194
1195 /* Strictly speaking, #ifdef below is not necessary. But we
1196 keep it to indicate that this kind of change may also be
1197 necessary for other unexecs to support GNUstep. */
1198 #ifdef NS_IMPL_GNUSTEP
1199 /* ObjC runtime modifies the values of some data structures
1200 such as classes and selectors in the .data section after
1201 loading. As the dump process copies the .data section
1202 from the current process, that causes problems when the
1203 modified classes are reinitialized in the dumped
1204 executable. We copy such data from the old file, not
1205 from the current process. */
1206 if (strncmp ((char *) (symnames + symp->st_name),
1207 "_OBJC_", sizeof ("_OBJC_") - 1) == 0)
1208 {
1209 caddr_t old, new;
1210
1211 new = ((symp->st_value - NEW_SECTION_H (symp->st_shndx).sh_addr)
1212 + NEW_SECTION_H (symp->st_shndx).sh_offset + new_base);
1213 /* "Unpatch" index. */
1214 nn = symp->st_shndx;
1215 if (nn > old_bss_index)
1216 nn--;
1217 old = ((symp->st_value - NEW_SECTION_H (symp->st_shndx).sh_addr)
1218 + OLD_SECTION_H (nn).sh_offset + old_base);
1219 memcpy (new, old, symp->st_size);
1220 }
1221 #endif
1222 }
1223 }
1224
1225 /* This loop seeks out relocation sections for the data section, so
1226 that it can undo relocations performed by the runtime linker. */
1227 for (n = new_file_h->e_shnum - 1; n; n--)
1228 {
1229 ElfW(Shdr) section = NEW_SECTION_H (n);
1230
1231 /* Cause a compilation error if anyone uses n instead of nn below. */
1232 struct {int a;} n;
1233 (void)n.a; /* Prevent `unused variable' warnings. */
1234
1235 switch (section.sh_type)
1236 {
1237 default:
1238 break;
1239 case SHT_REL:
1240 case SHT_RELA:
1241 /* This code handles two different size structs, but there should
1242 be no harm in that provided that r_offset is always the first
1243 member. */
1244 nn = section.sh_info;
1245 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
1246 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1247 ".sdata")
1248 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1249 ".lit4")
1250 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1251 ".lit8")
1252 #ifdef IRIX6_5 /* see above */
1253 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1254 ".got")
1255 #endif
1256 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1257 ".sdata1")
1258 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1259 ".data1"))
1260 {
1261 ElfW(Addr) offset = (NEW_SECTION_H (nn).sh_addr
1262 - NEW_SECTION_H (nn).sh_offset);
1263 caddr_t reloc = old_base + section.sh_offset, end;
1264 for (end = reloc + section.sh_size; reloc < end;
1265 reloc += section.sh_entsize)
1266 {
1267 ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
1268 #ifdef __alpha__
1269 /* The Alpha ELF binutils currently have a bug that
1270 sometimes results in relocs that contain all
1271 zeroes. Work around this for now... */
1272 if (((ElfW(Rel) *) reloc)->r_offset == 0)
1273 continue;
1274 #endif
1275 memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
1276 }
1277 }
1278 break;
1279 }
1280 }
1281
1282 /* Write out new_file, and free the buffers. */
1283
1284 if (write (new_file, new_base, new_file_size) != new_file_size)
1285 fatal ("Didn't write %d bytes to %s: errno %d\n",
1286 new_file_size, new_name, errno);
1287 munmap (old_base, old_file_size);
1288 munmap (new_base, new_file_size);
1289
1290 /* Close the files and make the new file executable. */
1291
1292 #if MAP_ANON == 0
1293 close (mmap_fd);
1294 #endif
1295
1296 if (close (old_file))
1297 fatal ("Can't close (%s): errno %d\n", old_name, errno);
1298
1299 if (close (new_file))
1300 fatal ("Can't close (%s): errno %d\n", new_name, errno);
1301
1302 if (stat (new_name, &stat_buf) == -1)
1303 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
1304
1305 n = umask (777);
1306 umask (n);
1307 stat_buf.st_mode |= 0111 & ~n;
1308 if (chmod (new_name, stat_buf.st_mode) == -1)
1309 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
1310 }
1311
1312 /* arch-tag: e02e1512-95e2-4ef0-bba7-b6bce658f1e3
1313 (do not change this comment) */