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[gnu-emacs] / src / unexelf.c
1 /* Copyright (C) 1985-1988, 1990, 1992, 1999-2011
2 Free Software Foundation, Inc.
3
4 This file is part of GNU Emacs.
5
6 GNU Emacs is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
10
11 GNU Emacs is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
18
19 /*
20 In other words, you are welcome to use, share and improve this program.
21 You are forbidden to forbid anyone else to use, share and improve
22 what you give them. Help stamp out software-hoarding! */
23
24
25 /*
26 * unexec.c - Convert a running program into an a.out file.
27 *
28 * Author: Spencer W. Thomas
29 * Computer Science Dept.
30 * University of Utah
31 * Date: Tue Mar 2 1982
32 * Modified heavily since then.
33 *
34 * Synopsis:
35 * unexec (const char *new_name, const char *old_name);
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 old_name is non-NULL, the symbol table will be taken from the given file.
40 * On some machines, an existing old_name file is required.
41 *
42 */
43
44 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
45 * ELF support added.
46 *
47 * Basic theory: the data space of the running process needs to be
48 * dumped to the output file. Normally we would just enlarge the size
49 * of .data, scooting everything down. But we can't do that in ELF,
50 * because there is often something between the .data space and the
51 * .bss space.
52 *
53 * In the temacs dump below, notice that the Global Offset Table
54 * (.got) and the Dynamic link data (.dynamic) come between .data1 and
55 * .bss. It does not work to overlap .data with these fields.
56 *
57 * The solution is to create a new .data segment. This segment is
58 * filled with data from the current process. Since the contents of
59 * various sections refer to sections by index, the new .data segment
60 * is made the last in the table to avoid changing any existing index.
61
62 * This is an example of how the section headers are changed. "Addr"
63 * is a process virtual address. "Offset" is a file offset.
64
65 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
66
67 temacs:
68
69 **** SECTION HEADER TABLE ****
70 [No] Type Flags Addr Offset Size Name
71 Link Info Adralgn Entsize
72
73 [1] 1 2 0x80480d4 0xd4 0x13 .interp
74 0 0 0x1 0
75
76 [2] 5 2 0x80480e8 0xe8 0x388 .hash
77 3 0 0x4 0x4
78
79 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
80 4 1 0x4 0x10
81
82 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
83 0 0 0x1 0
84
85 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
86 3 7 0x4 0x8
87
88 [6] 1 6 0x8049348 0x1348 0x3 .init
89 0 0 0x4 0
90
91 [7] 1 6 0x804934c 0x134c 0x680 .plt
92 0 0 0x4 0x4
93
94 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
95 0 0 0x4 0
96
97 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
98 0 0 0x4 0
99
100 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
101 0 0 0x4 0
102
103 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
104 0 0 0x4 0
105
106 [12] 1 3 0x8088330 0x3f330 0x20afc .data
107 0 0 0x4 0
108
109 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
110 0 0 0x4 0
111
112 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
113 0 0 0x4 0x4
114
115 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
116 4 0 0x4 0x8
117
118 [16] 8 3 0x80a98f4 0x608f4 0x449c .bss
119 0 0 0x4 0
120
121 [17] 2 0 0 0x608f4 0x9b90 .symtab
122 18 371 0x4 0x10
123
124 [18] 3 0 0 0x6a484 0x8526 .strtab
125 0 0 0x1 0
126
127 [19] 3 0 0 0x729aa 0x93 .shstrtab
128 0 0 0x1 0
129
130 [20] 1 0 0 0x72a3d 0x68b7 .comment
131 0 0 0x1 0
132
133 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
134
135 xemacs:
136
137 **** SECTION HEADER TABLE ****
138 [No] Type Flags Addr Offset Size Name
139 Link Info Adralgn Entsize
140
141 [1] 1 2 0x80480d4 0xd4 0x13 .interp
142 0 0 0x1 0
143
144 [2] 5 2 0x80480e8 0xe8 0x388 .hash
145 3 0 0x4 0x4
146
147 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
148 4 1 0x4 0x10
149
150 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
151 0 0 0x1 0
152
153 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
154 3 7 0x4 0x8
155
156 [6] 1 6 0x8049348 0x1348 0x3 .init
157 0 0 0x4 0
158
159 [7] 1 6 0x804934c 0x134c 0x680 .plt
160 0 0 0x4 0x4
161
162 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
163 0 0 0x4 0
164
165 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
166 0 0 0x4 0
167
168 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
169 0 0 0x4 0
170
171 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
172 0 0 0x4 0
173
174 [12] 1 3 0x8088330 0x3f330 0x20afc .data
175 0 0 0x4 0
176
177 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
178 0 0 0x4 0
179
180 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
181 0 0 0x4 0x4
182
183 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
184 4 0 0x4 0x8
185
186 [16] 8 3 0x80c6800 0x7d800 0 .bss
187 0 0 0x4 0
188
189 [17] 2 0 0 0x7d800 0x9b90 .symtab
190 18 371 0x4 0x10
191
192 [18] 3 0 0 0x87390 0x8526 .strtab
193 0 0 0x1 0
194
195 [19] 3 0 0 0x8f8b6 0x93 .shstrtab
196 0 0 0x1 0
197
198 [20] 1 0 0 0x8f949 0x68b7 .comment
199 0 0 0x1 0
200
201 [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
202 0 0 0x4 0
203
204 * This is an example of how the file header is changed. "Shoff" is
205 * the section header offset within the file. Since that table is
206 * after the new .data section, it is moved. "Shnum" is the number of
207 * sections, which we increment.
208 *
209 * "Phoff" is the file offset to the program header. "Phentsize" and
210 * "Shentsz" are the program and section header entries sizes respectively.
211 * These can be larger than the apparent struct sizes.
212
213 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
214
215 temacs:
216
217 **** ELF HEADER ****
218 Class Data Type Machine Version
219 Entry Phoff Shoff Flags Ehsize
220 Phentsize Phnum Shentsz Shnum Shstrndx
221
222 1 1 2 3 1
223 0x80499cc 0x34 0x792f4 0 0x34
224 0x20 5 0x28 21 19
225
226 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
227
228 xemacs:
229
230 **** ELF HEADER ****
231 Class Data Type Machine Version
232 Entry Phoff Shoff Flags Ehsize
233 Phentsize Phnum Shentsz Shnum Shstrndx
234
235 1 1 2 3 1
236 0x80499cc 0x34 0x96200 0 0x34
237 0x20 5 0x28 22 19
238
239 * These are the program headers. "Offset" is the file offset to the
240 * segment. "Vaddr" is the memory load address. "Filesz" is the
241 * segment size as it appears in the file, and "Memsz" is the size in
242 * memory. Below, the third segment is the code and the fourth is the
243 * data: the difference between Filesz and Memsz is .bss
244
245 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
246
247 temacs:
248 ***** PROGRAM EXECUTION HEADER *****
249 Type Offset Vaddr Paddr
250 Filesz Memsz Flags Align
251
252 6 0x34 0x8048034 0
253 0xa0 0xa0 5 0
254
255 3 0xd4 0 0
256 0x13 0 4 0
257
258 1 0x34 0x8048034 0
259 0x3f2f9 0x3f2f9 5 0x1000
260
261 1 0x3f330 0x8088330 0
262 0x215c4 0x25a60 7 0x1000
263
264 2 0x60874 0x80a9874 0
265 0x80 0 7 0
266
267 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
268
269 xemacs:
270 ***** PROGRAM EXECUTION HEADER *****
271 Type Offset Vaddr Paddr
272 Filesz Memsz Flags Align
273
274 6 0x34 0x8048034 0
275 0xa0 0xa0 5 0
276
277 3 0xd4 0 0
278 0x13 0 4 0
279
280 1 0x34 0x8048034 0
281 0x3f2f9 0x3f2f9 5 0x1000
282
283 1 0x3f330 0x8088330 0
284 0x3e4d0 0x3e4d0 7 0x1000
285
286 2 0x60874 0x80a9874 0
287 0x80 0 7 0
288
289
290 */
291 \f
292 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
293 *
294 * The above mechanism does not work if the unexeced ELF file is being
295 * re-layout by other applications (such as `strip'). All the applications
296 * that re-layout the internal of ELF will layout all sections in ascending
297 * order of their file offsets. After the re-layout, the data2 section will
298 * still be the LAST section in the section header vector, but its file offset
299 * is now being pushed far away down, and causes part of it not to be mapped
300 * in (ie. not covered by the load segment entry in PHDR vector), therefore
301 * causes the new binary to fail.
302 *
303 * The solution is to modify the unexec algorithm to insert the new data2
304 * section header right before the new bss section header, so their file
305 * offsets will be in the ascending order. Since some of the section's (all
306 * sections AFTER the bss section) indexes are now changed, we also need to
307 * modify some fields to make them point to the right sections. This is done
308 * by macro PATCH_INDEX. All the fields that need to be patched are:
309 *
310 * 1. ELF header e_shstrndx field.
311 * 2. section header sh_link and sh_info field.
312 * 3. symbol table entry st_shndx field.
313 *
314 * The above example now should look like:
315
316 **** SECTION HEADER TABLE ****
317 [No] Type Flags Addr Offset Size Name
318 Link Info Adralgn Entsize
319
320 [1] 1 2 0x80480d4 0xd4 0x13 .interp
321 0 0 0x1 0
322
323 [2] 5 2 0x80480e8 0xe8 0x388 .hash
324 3 0 0x4 0x4
325
326 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
327 4 1 0x4 0x10
328
329 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
330 0 0 0x1 0
331
332 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
333 3 7 0x4 0x8
334
335 [6] 1 6 0x8049348 0x1348 0x3 .init
336 0 0 0x4 0
337
338 [7] 1 6 0x804934c 0x134c 0x680 .plt
339 0 0 0x4 0x4
340
341 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
342 0 0 0x4 0
343
344 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
345 0 0 0x4 0
346
347 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
348 0 0 0x4 0
349
350 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
351 0 0 0x4 0
352
353 [12] 1 3 0x8088330 0x3f330 0x20afc .data
354 0 0 0x4 0
355
356 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
357 0 0 0x4 0
358
359 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
360 0 0 0x4 0x4
361
362 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
363 4 0 0x4 0x8
364
365 [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
366 0 0 0x4 0
367
368 [17] 8 3 0x80c6800 0x7d800 0 .bss
369 0 0 0x4 0
370
371 [18] 2 0 0 0x7d800 0x9b90 .symtab
372 19 371 0x4 0x10
373
374 [19] 3 0 0 0x87390 0x8526 .strtab
375 0 0 0x1 0
376
377 [20] 3 0 0 0x8f8b6 0x93 .shstrtab
378 0 0 0x1 0
379
380 [21] 1 0 0 0x8f949 0x68b7 .comment
381 0 0 0x1 0
382
383 */
384 \f
385 /* We do not use mmap because that fails with NFS.
386 Instead we read the whole file, modify it, and write it out. */
387
388 #include <config.h>
389 extern void fatal (const char *msgid, ...);
390
391 #include <sys/types.h>
392 #include <stdio.h>
393 #include <sys/stat.h>
394 #include <memory.h>
395 #include <errno.h>
396 #include <unistd.h>
397 #include <fcntl.h>
398 #if !defined (__NetBSD__) && !defined (__OpenBSD__)
399 #include <elf.h>
400 #endif /* not __NetBSD__ and not __OpenBSD__ */
401 #include <sys/mman.h>
402 #if defined (_SYSTYPE_SYSV)
403 #include <sys/elf_mips.h>
404 #include <sym.h>
405 #endif /* _SYSTYPE_SYSV */
406 #if __sgi
407 #include <syms.h> /* for HDRR declaration */
408 #endif /* __sgi */
409
410 #ifndef MAP_ANON
411 #ifdef MAP_ANONYMOUS
412 #define MAP_ANON MAP_ANONYMOUS
413 #else
414 #define MAP_ANON 0
415 #endif
416 #endif
417
418 #ifndef MAP_FAILED
419 #define MAP_FAILED ((void *) -1)
420 #endif
421
422 #if defined (__alpha__) && !defined (__NetBSD__) && !defined (__OpenBSD__)
423 /* Declare COFF debugging symbol table. This used to be in
424 /usr/include/sym.h, but this file is no longer included in Red Hat
425 5.0 and presumably in any other glibc 2.x based distribution. */
426 typedef struct {
427 short magic;
428 short vstamp;
429 int ilineMax;
430 int idnMax;
431 int ipdMax;
432 int isymMax;
433 int ioptMax;
434 int iauxMax;
435 int issMax;
436 int issExtMax;
437 int ifdMax;
438 int crfd;
439 int iextMax;
440 long cbLine;
441 long cbLineOffset;
442 long cbDnOffset;
443 long cbPdOffset;
444 long cbSymOffset;
445 long cbOptOffset;
446 long cbAuxOffset;
447 long cbSsOffset;
448 long cbSsExtOffset;
449 long cbFdOffset;
450 long cbRfdOffset;
451 long cbExtOffset;
452 } HDRR, *pHDRR;
453 #define cbHDRR sizeof(HDRR)
454 #define hdrNil ((pHDRR)0)
455 #endif
456
457 #ifdef __NetBSD__
458 /*
459 * NetBSD does not have normal-looking user-land ELF support.
460 */
461 # if defined __alpha__ || defined __sparc_v9__
462 # define ELFSIZE 64
463 # else
464 # define ELFSIZE 32
465 # endif
466 # include <sys/exec_elf.h>
467
468 # ifndef PT_LOAD
469 # define PT_LOAD Elf_pt_load
470 # if 0 /* was in pkgsrc patches for 20.7 */
471 # define SHT_PROGBITS Elf_sht_progbits
472 # endif
473 # define SHT_SYMTAB Elf_sht_symtab
474 # define SHT_DYNSYM Elf_sht_dynsym
475 # define SHT_NULL Elf_sht_null
476 # define SHT_NOBITS Elf_sht_nobits
477 # define SHT_REL Elf_sht_rel
478 # define SHT_RELA Elf_sht_rela
479
480 # define SHN_UNDEF Elf_eshn_undefined
481 # define SHN_ABS Elf_eshn_absolute
482 # define SHN_COMMON Elf_eshn_common
483 # endif /* !PT_LOAD */
484
485 # ifdef __alpha__
486 # include <sys/exec_ecoff.h>
487 # define HDRR struct ecoff_symhdr
488 # define pHDRR HDRR *
489 # endif /* __alpha__ */
490
491 #ifdef __mips__ /* was in pkgsrc patches for 20.7 */
492 # define SHT_MIPS_DEBUG DT_MIPS_FLAGS
493 # define HDRR struct Elf_Shdr
494 #endif /* __mips__ */
495 #endif /* __NetBSD__ */
496
497 #ifdef __OpenBSD__
498 # include <sys/exec_elf.h>
499 #endif
500
501 #if __GNU_LIBRARY__ - 0 >= 6
502 # include <link.h> /* get ElfW etc */
503 #endif
504
505 #ifndef ElfW
506 # ifdef __STDC__
507 # define ElfBitsW(bits, type) Elf##bits##_##type
508 # else
509 # define ElfBitsW(bits, type) Elf/**/bits/**/_/**/type
510 # endif
511 # ifdef _LP64
512 # define ELFSIZE 64
513 # else
514 # define ELFSIZE 32
515 # endif
516 /* This macro expands `bits' before invoking ElfBitsW. */
517 # define ElfExpandBitsW(bits, type) ElfBitsW (bits, type)
518 # define ElfW(type) ElfExpandBitsW (ELFSIZE, type)
519 #endif
520
521 #ifndef ELF_BSS_SECTION_NAME
522 #define ELF_BSS_SECTION_NAME ".bss"
523 #endif
524
525 /* Get the address of a particular section or program header entry,
526 * accounting for the size of the entries.
527 */
528 /*
529 On PPC Reference Platform running Solaris 2.5.1
530 the plt section is also of type NOBI like the bss section.
531 (not really stored) and therefore sections after the bss
532 section start at the plt offset. The plt section is always
533 the one just before the bss section.
534 Thus, we modify the test from
535 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
536 to
537 if (NEW_SECTION_H (nn).sh_offset >=
538 OLD_SECTION_H (old_bss_index-1).sh_offset)
539 This is just a hack. We should put the new data section
540 before the .plt section.
541 And we should not have this routine at all but use
542 the libelf library to read the old file and create the new
543 file.
544 The changed code is minimal and depends on prep set in m/prep.h
545 Erik Deumens
546 Quantum Theory Project
547 University of Florida
548 deumens@qtp.ufl.edu
549 Apr 23, 1996
550 */
551
552 #define OLD_SECTION_H(n) \
553 (*(ElfW(Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
554 #define NEW_SECTION_H(n) \
555 (*(ElfW(Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
556 #define OLD_PROGRAM_H(n) \
557 (*(ElfW(Phdr) *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
558 #define NEW_PROGRAM_H(n) \
559 (*(ElfW(Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
560
561 #define PATCH_INDEX(n) \
562 do { \
563 if ((int) (n) >= old_bss_index) \
564 (n)++; } while (0)
565 typedef unsigned char byte;
566
567 /* Round X up to a multiple of Y. */
568
569 static ElfW(Addr)
570 round_up (ElfW(Addr) x, ElfW(Addr) y)
571 {
572 int rem = x % y;
573 if (rem == 0)
574 return x;
575 return x - rem + y;
576 }
577
578 /* Return the index of the section named NAME.
579 SECTION_NAMES, FILE_NAME and FILE_H give information
580 about the file we are looking in.
581
582 If we don't find the section NAME, that is a fatal error
583 if NOERROR is 0; we return -1 if NOERROR is nonzero. */
584
585 static int
586 find_section (const char *name, const char *section_names, const char *file_name,
587 ElfW(Ehdr) *old_file_h, ElfW(Shdr) *old_section_h, int noerror)
588 {
589 int idx;
590
591 for (idx = 1; idx < old_file_h->e_shnum; idx++)
592 {
593 #ifdef DEBUG
594 fprintf (stderr, "Looking for %s - found %s\n", name,
595 section_names + OLD_SECTION_H (idx).sh_name);
596 #endif
597 if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
598 name))
599 break;
600 }
601 if (idx == old_file_h->e_shnum)
602 {
603 if (noerror)
604 return -1;
605 else
606 fatal ("Can't find %s in %s.\n", name, file_name);
607 }
608
609 return idx;
610 }
611
612 /* ****************************************************************
613 * unexec
614 *
615 * driving logic.
616 *
617 * In ELF, this works by replacing the old .bss section with a new
618 * .data section, and inserting an empty .bss immediately afterwards.
619 *
620 */
621 void
622 unexec (const char *new_name, const char *old_name)
623 {
624 int new_file, old_file, new_file_size;
625
626 /* Pointers to the base of the image of the two files. */
627 caddr_t old_base, new_base;
628
629 #if MAP_ANON == 0
630 int mmap_fd;
631 #else
632 # define mmap_fd -1
633 #endif
634
635 /* Pointers to the file, program and section headers for the old and
636 new files. */
637 ElfW(Ehdr) *old_file_h, *new_file_h;
638 ElfW(Phdr) *old_program_h, *new_program_h;
639 ElfW(Shdr) *old_section_h, *new_section_h;
640
641 /* Point to the section name table in the old file. */
642 char *old_section_names;
643
644 ElfW(Addr) old_bss_addr, new_bss_addr;
645 ElfW(Word) old_bss_size, new_data2_size;
646 ElfW(Off) new_data2_offset;
647 ElfW(Addr) new_data2_addr;
648 ElfW(Off) old_bss_offset;
649 ElfW(Word) new_data2_incr;
650
651 int n, nn;
652 int old_bss_index, old_sbss_index, old_plt_index;
653 int old_data_index, new_data2_index;
654 int old_mdebug_index;
655 struct stat stat_buf;
656 int old_file_size;
657
658 /* Open the old file, allocate a buffer of the right size, and read
659 in the file contents. */
660
661 old_file = open (old_name, O_RDONLY);
662
663 if (old_file < 0)
664 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
665
666 if (fstat (old_file, &stat_buf) == -1)
667 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
668
669 #if MAP_ANON == 0
670 mmap_fd = open ("/dev/zero", O_RDONLY);
671 if (mmap_fd < 0)
672 fatal ("Can't open /dev/zero for reading: errno %d\n", errno, 0);
673 #endif
674
675 /* We cannot use malloc here because that may use sbrk. If it does,
676 we'd dump our temporary buffers with Emacs, and we'd have to be
677 extra careful to use the correct value of sbrk(0) after
678 allocating all buffers in the code below, which we aren't. */
679 old_file_size = stat_buf.st_size;
680 old_base = mmap (NULL, old_file_size, PROT_READ | PROT_WRITE,
681 MAP_ANON | MAP_PRIVATE, mmap_fd, 0);
682 if (old_base == MAP_FAILED)
683 fatal ("Can't allocate buffer for %s\n", old_name, 0);
684
685 if (read (old_file, old_base, stat_buf.st_size) != stat_buf.st_size)
686 fatal ("Didn't read all of %s: errno %d\n", old_name, errno);
687
688 /* Get pointers to headers & section names */
689
690 old_file_h = (ElfW(Ehdr) *) old_base;
691 old_program_h = (ElfW(Phdr) *) ((byte *) old_base + old_file_h->e_phoff);
692 old_section_h = (ElfW(Shdr) *) ((byte *) old_base + old_file_h->e_shoff);
693 old_section_names = (char *) old_base
694 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
695
696 /* Find the mdebug section, if any. */
697
698 old_mdebug_index = find_section (".mdebug", old_section_names,
699 old_name, old_file_h, old_section_h, 1);
700
701 /* Find the old .bss section. Figure out parameters of the new
702 data2 and bss sections. */
703
704 old_bss_index = find_section (".bss", old_section_names,
705 old_name, old_file_h, old_section_h, 0);
706
707 old_sbss_index = find_section (".sbss", old_section_names,
708 old_name, old_file_h, old_section_h, 1);
709 if (old_sbss_index != -1)
710 if (OLD_SECTION_H (old_sbss_index).sh_type != SHT_NOBITS)
711 old_sbss_index = -1;
712
713 /* PowerPC64 has .plt in the BSS section. */
714 old_plt_index = find_section (".plt", old_section_names,
715 old_name, old_file_h, old_section_h, 1);
716 if (old_plt_index != -1)
717 if (OLD_SECTION_H (old_plt_index).sh_type != SHT_NOBITS)
718 old_plt_index = -1;
719
720 if (old_sbss_index == -1 && old_plt_index == -1)
721 {
722 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
723 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
724 old_bss_offset = OLD_SECTION_H (old_bss_index).sh_offset;
725 new_data2_index = old_bss_index;
726 }
727 else if (old_plt_index != -1
728 && (old_sbss_index == -1
729 || (OLD_SECTION_H (old_sbss_index).sh_addr
730 > OLD_SECTION_H (old_plt_index).sh_addr)))
731 {
732 old_bss_addr = OLD_SECTION_H (old_plt_index).sh_addr;
733 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size
734 + OLD_SECTION_H (old_plt_index).sh_size;
735 if (old_sbss_index != -1)
736 old_bss_size += OLD_SECTION_H (old_sbss_index).sh_size;
737 old_bss_offset = OLD_SECTION_H (old_plt_index).sh_offset;
738 new_data2_index = old_plt_index;
739 }
740 else
741 {
742 old_bss_addr = OLD_SECTION_H (old_sbss_index).sh_addr;
743 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size
744 + OLD_SECTION_H (old_sbss_index).sh_size;
745 old_bss_offset = OLD_SECTION_H (old_sbss_index).sh_offset;
746 new_data2_index = old_sbss_index;
747 }
748
749 /* Find the old .data section. Figure out parameters of
750 the new data2 and bss sections. */
751
752 old_data_index = find_section (".data", old_section_names,
753 old_name, old_file_h, old_section_h, 0);
754
755 #if defined (emacs) || !defined (DEBUG)
756 new_bss_addr = (ElfW(Addr)) sbrk (0);
757 #else
758 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
759 #endif
760 new_data2_addr = old_bss_addr;
761 new_data2_size = new_bss_addr - old_bss_addr;
762 new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset
763 + (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
764 /* This is the amount by which the sections following the bss sections
765 must be shifted in the image. It can differ from new_data2_size if
766 the end of the old .data section (and thus the offset of the .bss
767 section) was unaligned. */
768 new_data2_incr = new_data2_size + (new_data2_offset - old_bss_offset);
769
770 #ifdef DEBUG
771 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
772 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
773 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
774 fprintf (stderr, "old_bss_offset %x\n", old_bss_offset);
775 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
776 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
777 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
778 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
779 fprintf (stderr, "new_data2_incr %x\n", new_data2_incr);
780 #endif
781
782 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
783 fatal (".bss shrank when undumping???\n", 0, 0);
784
785 /* Set the output file to the right size. Allocate a buffer to hold
786 the image of the new file. Set pointers to various interesting
787 objects. stat_buf still has old_file data. */
788
789 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
790 if (new_file < 0)
791 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
792
793 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_incr;
794
795 if (ftruncate (new_file, new_file_size))
796 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
797
798 new_base = mmap (NULL, new_file_size, PROT_READ | PROT_WRITE,
799 MAP_ANON | MAP_PRIVATE, mmap_fd, 0);
800 if (new_base == MAP_FAILED)
801 fatal ("Can't allocate buffer for %s\n", old_name, 0);
802
803 new_file_h = (ElfW(Ehdr) *) new_base;
804 new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
805 new_section_h = (ElfW(Shdr) *)
806 ((byte *) new_base + old_file_h->e_shoff + new_data2_incr);
807
808 /* Make our new file, program and section headers as copies of the
809 originals. */
810
811 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
812 memcpy (new_program_h, old_program_h,
813 old_file_h->e_phnum * old_file_h->e_phentsize);
814
815 /* Modify the e_shstrndx if necessary. */
816 PATCH_INDEX (new_file_h->e_shstrndx);
817
818 /* Fix up file header. We'll add one section. Section header is
819 further away now. */
820
821 new_file_h->e_shoff += new_data2_incr;
822 new_file_h->e_shnum += 1;
823
824 #ifdef DEBUG
825 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
826 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
827 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
828 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
829 #endif
830
831 /* Fix up a new program header. Extend the writable data segment so
832 that the bss area is covered too. Find that segment by looking
833 for a segment that ends just before the .bss area. Make sure
834 that no segments are above the new .data2. Put a loop at the end
835 to adjust the offset and address of any segment that is above
836 data2, just in case we decide to allow this later. */
837
838 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
839 {
840 /* Compute maximum of all requirements for alignment of section. */
841 ElfW(Word) alignment = (NEW_PROGRAM_H (n)).p_align;
842 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
843 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
844
845 #ifdef __sgi
846 /* According to r02kar@x4u2.desy.de (Karsten Kuenne)
847 and oliva@gnu.org (Alexandre Oliva), on IRIX 5.2, we
848 always get "Program segment above .bss" when dumping
849 when the executable doesn't have an sbss section. */
850 if (old_sbss_index != -1)
851 #endif /* __sgi */
852 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz
853 > (old_sbss_index == -1
854 ? old_bss_addr
855 : round_up (old_bss_addr, alignment)))
856 fatal ("Program segment above .bss in %s\n", old_name, 0);
857
858 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
859 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
860 + (NEW_PROGRAM_H (n)).p_filesz,
861 alignment)
862 == round_up (old_bss_addr, alignment)))
863 break;
864 }
865 if (n < 0)
866 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
867
868 /* Make sure that the size includes any padding before the old .bss
869 section. */
870 NEW_PROGRAM_H (n).p_filesz = new_bss_addr - NEW_PROGRAM_H (n).p_vaddr;
871 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
872
873 #if 0 /* Maybe allow section after data2 - does this ever happen? */
874 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
875 {
876 if (NEW_PROGRAM_H (n).p_vaddr
877 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
878 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
879
880 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
881 NEW_PROGRAM_H (n).p_offset += new_data2_incr;
882 }
883 #endif
884
885 /* Fix up section headers based on new .data2 section. Any section
886 whose offset or virtual address is after the new .data2 section
887 gets its value adjusted. .bss size becomes zero and new address
888 is set. data2 section header gets added by copying the existing
889 .data header and modifying the offset, address and size. */
890
891 /* Walk through all section headers, insert the new data2 section right
892 before the new bss section. */
893 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
894 {
895 caddr_t src;
896 /* If it is (s)bss section, insert the new data2 section before it. */
897 /* new_data2_index is the index of either old_sbss or old_bss, that was
898 chosen as a section for new_data2. */
899 if (n == new_data2_index)
900 {
901 /* Steal the data section header for this data2 section. */
902 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
903 new_file_h->e_shentsize);
904
905 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
906 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
907 NEW_SECTION_H (nn).sh_size = new_data2_size;
908 /* Use the bss section's alignment. This will assure that the
909 new data2 section always be placed in the same spot as the old
910 bss section by any other application. */
911 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
912
913 /* Now copy over what we have in the memory now. */
914 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
915 (caddr_t) OLD_SECTION_H (n).sh_addr,
916 new_data2_size);
917 nn++;
918 }
919
920 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
921 old_file_h->e_shentsize);
922
923 if (n == old_bss_index
924 /* The new bss and sbss section's size is zero, and its file offset
925 and virtual address should be off by NEW_DATA2_SIZE. */
926 || n == old_sbss_index || n == old_plt_index
927 )
928 {
929 /* NN should be `old_s?bss_index + 1' at this point. */
930 NEW_SECTION_H (nn).sh_offset = new_data2_offset + new_data2_size;
931 NEW_SECTION_H (nn).sh_addr = new_data2_addr + new_data2_size;
932 /* Let the new bss section address alignment be the same as the
933 section address alignment followed the old bss section, so
934 this section will be placed in exactly the same place. */
935 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
936 NEW_SECTION_H (nn).sh_size = 0;
937 }
938 else
939 {
940 /* Any section that was originally placed after the .bss
941 section should now be off by NEW_DATA2_INCR. If a
942 section overlaps the .bss section, consider it to be
943 placed after the .bss section. Overlap can occur if the
944 section just before .bss has less-strict alignment; this
945 was observed between .symtab and .bss on Solaris 2.5.1
946 (sparc) with GCC snapshot 960602.
947
948 > dump -h temacs
949
950 temacs:
951
952 **** SECTION HEADER TABLE ****
953 [No] Type Flags Addr Offset Size Name
954 Link Info Adralgn Entsize
955
956 [22] 1 3 0x335150 0x315150 0x4 .data.rel.local
957 0 0 0x4 0
958
959 [23] 8 3 0x335158 0x315158 0x42720 .bss
960 0 0 0x8 0
961
962 [24] 2 0 0 0x315154 0x1c9d0 .symtab
963 25 1709 0x4 0x10
964 */
965
966 if (NEW_SECTION_H (nn).sh_offset >= old_bss_offset
967 || (NEW_SECTION_H (nn).sh_offset + NEW_SECTION_H (nn).sh_size
968 > new_data2_offset))
969 NEW_SECTION_H (nn).sh_offset += new_data2_incr;
970
971 /* Any section that was originally placed after the section
972 header table should now be off by the size of one section
973 header table entry. */
974 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
975 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
976 }
977
978 /* If any section hdr refers to the section after the new .data
979 section, make it refer to next one because we have inserted
980 a new section in between. */
981
982 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
983 /* For symbol tables, info is a symbol table index,
984 so don't change it. */
985 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
986 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
987 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
988
989 if (old_sbss_index != -1)
990 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".sbss"))
991 {
992 NEW_SECTION_H (nn).sh_offset =
993 round_up (NEW_SECTION_H (nn).sh_offset,
994 NEW_SECTION_H (nn).sh_addralign);
995 NEW_SECTION_H (nn).sh_type = SHT_PROGBITS;
996 }
997
998 /* Now, start to copy the content of sections. */
999 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
1000 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
1001 continue;
1002
1003 /* Write out the sections. .data and .data1 (and data2, called
1004 ".data" in the strings table) get copied from the current process
1005 instead of the old file. */
1006 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
1007 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1008 ".sdata")
1009 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1010 ".lit4")
1011 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1012 ".lit8")
1013 /* The conditional bit below was in Oliva's original code
1014 (1999-08-25) and seems to have been dropped by mistake
1015 subsequently. It prevents a crash at startup under X in
1016 `IRIX64 6.5 6.5.17m', whether compiled on that relase or
1017 an earlier one. It causes no trouble on the other ELF
1018 platforms I could test (Irix 6.5.15m, Solaris 8, Debian
1019 Potato x86, Debian Woody SPARC); however, it's reported
1020 to cause crashes under some version of GNU/Linux. It's
1021 not yet clear what's changed in that Irix version to
1022 cause the problem, or why the fix sometimes fails under
1023 GNU/Linux. There's probably no good reason to have
1024 something Irix-specific here, but this will have to do
1025 for now. IRIX6_5 is the most specific macro we have to
1026 test. -- fx 2002-10-01
1027
1028 The issue _looks_ as though it's gone away on 6.5.18m,
1029 but maybe it's still lurking, to be triggered by some
1030 change in the binary. It appears to concern the dynamic
1031 loader, but I never got anywhere with an SGI support call
1032 seeking clues. -- fx 2002-11-29. */
1033 #ifdef IRIX6_5
1034 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1035 ".got")
1036 #endif
1037 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1038 ".sdata1")
1039 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1040 ".data1")
1041 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1042 ".sbss"))
1043 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
1044 else
1045 src = old_base + OLD_SECTION_H (n).sh_offset;
1046
1047 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
1048 NEW_SECTION_H (nn).sh_size);
1049
1050 #ifdef __alpha__
1051 /* Update Alpha COFF symbol table: */
1052 if (strcmp (old_section_names + OLD_SECTION_H (n).sh_name, ".mdebug")
1053 == 0)
1054 {
1055 pHDRR symhdr = (pHDRR) (NEW_SECTION_H (nn).sh_offset + new_base);
1056
1057 symhdr->cbLineOffset += new_data2_size;
1058 symhdr->cbDnOffset += new_data2_size;
1059 symhdr->cbPdOffset += new_data2_size;
1060 symhdr->cbSymOffset += new_data2_size;
1061 symhdr->cbOptOffset += new_data2_size;
1062 symhdr->cbAuxOffset += new_data2_size;
1063 symhdr->cbSsOffset += new_data2_size;
1064 symhdr->cbSsExtOffset += new_data2_size;
1065 symhdr->cbFdOffset += new_data2_size;
1066 symhdr->cbRfdOffset += new_data2_size;
1067 symhdr->cbExtOffset += new_data2_size;
1068 }
1069 #endif /* __alpha__ */
1070
1071 #if defined (_SYSTYPE_SYSV)
1072 if (NEW_SECTION_H (nn).sh_type == SHT_MIPS_DEBUG
1073 && old_mdebug_index != -1)
1074 {
1075 int diff = NEW_SECTION_H(nn).sh_offset
1076 - OLD_SECTION_H(old_mdebug_index).sh_offset;
1077 HDRR *phdr = (HDRR *)(NEW_SECTION_H (nn).sh_offset + new_base);
1078
1079 if (diff)
1080 {
1081 phdr->cbLineOffset += diff;
1082 phdr->cbDnOffset += diff;
1083 phdr->cbPdOffset += diff;
1084 phdr->cbSymOffset += diff;
1085 phdr->cbOptOffset += diff;
1086 phdr->cbAuxOffset += diff;
1087 phdr->cbSsOffset += diff;
1088 phdr->cbSsExtOffset += diff;
1089 phdr->cbFdOffset += diff;
1090 phdr->cbRfdOffset += diff;
1091 phdr->cbExtOffset += diff;
1092 }
1093 }
1094 #endif /* _SYSTYPE_SYSV */
1095
1096 #if __sgi
1097 /* Adjust the HDRR offsets in .mdebug and copy the
1098 line data if it's in its usual 'hole' in the object.
1099 Makes the new file debuggable with dbx.
1100 patches up two problems: the absolute file offsets
1101 in the HDRR record of .mdebug (see /usr/include/syms.h), and
1102 the ld bug that gets the line table in a hole in the
1103 elf file rather than in the .mdebug section proper.
1104 David Anderson. davea@sgi.com Jan 16,1994. */
1105 if (n == old_mdebug_index)
1106 {
1107 #define MDEBUGADJUST(__ct,__fileaddr) \
1108 if (n_phdrr->__ct > 0) \
1109 { \
1110 n_phdrr->__fileaddr += movement; \
1111 }
1112
1113 HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset);
1114 HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset);
1115 unsigned movement = new_data2_size;
1116
1117 MDEBUGADJUST (idnMax, cbDnOffset);
1118 MDEBUGADJUST (ipdMax, cbPdOffset);
1119 MDEBUGADJUST (isymMax, cbSymOffset);
1120 MDEBUGADJUST (ioptMax, cbOptOffset);
1121 MDEBUGADJUST (iauxMax, cbAuxOffset);
1122 MDEBUGADJUST (issMax, cbSsOffset);
1123 MDEBUGADJUST (issExtMax, cbSsExtOffset);
1124 MDEBUGADJUST (ifdMax, cbFdOffset);
1125 MDEBUGADJUST (crfd, cbRfdOffset);
1126 MDEBUGADJUST (iextMax, cbExtOffset);
1127 /* The Line Section, being possible off in a hole of the object,
1128 requires special handling. */
1129 if (n_phdrr->cbLine > 0)
1130 {
1131 if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset
1132 + OLD_SECTION_H (n).sh_size))
1133 {
1134 /* line data is in a hole in elf. do special copy and adjust
1135 for this ld mistake.
1136 */
1137 n_phdrr->cbLineOffset += movement;
1138
1139 memcpy (n_phdrr->cbLineOffset + new_base,
1140 o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
1141 }
1142 else
1143 {
1144 /* somehow line data is in .mdebug as it is supposed to be. */
1145 MDEBUGADJUST (cbLine, cbLineOffset);
1146 }
1147 }
1148 }
1149 #endif /* __sgi */
1150
1151 /* If it is the symbol table, its st_shndx field needs to be patched. */
1152 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
1153 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
1154 {
1155 ElfW(Shdr) *spt = &NEW_SECTION_H (nn);
1156 unsigned int num = spt->sh_size / spt->sh_entsize;
1157 ElfW(Sym) * sym = (ElfW(Sym) *) (NEW_SECTION_H (nn).sh_offset +
1158 new_base);
1159 for (; num--; sym++)
1160 {
1161 if ((sym->st_shndx == SHN_UNDEF)
1162 || (sym->st_shndx == SHN_ABS)
1163 || (sym->st_shndx == SHN_COMMON))
1164 continue;
1165
1166 PATCH_INDEX (sym->st_shndx);
1167 }
1168 }
1169 }
1170
1171 /* Update the symbol values of _edata and _end. */
1172 for (n = new_file_h->e_shnum - 1; n; n--)
1173 {
1174 byte *symnames;
1175 ElfW(Sym) *symp, *symendp;
1176
1177 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
1178 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
1179 continue;
1180
1181 symnames = ((byte *) new_base
1182 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
1183 symp = (ElfW(Sym) *) (NEW_SECTION_H (n).sh_offset + new_base);
1184 symendp = (ElfW(Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
1185
1186 for (; symp < symendp; symp ++)
1187 {
1188 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
1189 || strcmp ((char *) (symnames + symp->st_name), "end") == 0
1190 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0
1191 || strcmp ((char *) (symnames + symp->st_name), "edata") == 0)
1192 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
1193
1194 /* Strictly speaking, #ifdef below is not necessary. But we
1195 keep it to indicate that this kind of change may also be
1196 necessary for other unexecs to support GNUstep. */
1197 #ifdef NS_IMPL_GNUSTEP
1198 /* ObjC runtime modifies the values of some data structures
1199 such as classes and selectors in the .data section after
1200 loading. As the dump process copies the .data section
1201 from the current process, that causes problems when the
1202 modified classes are reinitialized in the dumped
1203 executable. We copy such data from the old file, not
1204 from the current process. */
1205 if (strncmp ((char *) (symnames + symp->st_name),
1206 "_OBJC_", sizeof ("_OBJC_") - 1) == 0)
1207 {
1208 caddr_t old, new;
1209
1210 new = ((symp->st_value - NEW_SECTION_H (symp->st_shndx).sh_addr)
1211 + NEW_SECTION_H (symp->st_shndx).sh_offset + new_base);
1212 /* "Unpatch" index. */
1213 nn = symp->st_shndx;
1214 if (nn > old_bss_index)
1215 nn--;
1216 old = ((symp->st_value - NEW_SECTION_H (symp->st_shndx).sh_addr)
1217 + OLD_SECTION_H (nn).sh_offset + old_base);
1218 memcpy (new, old, symp->st_size);
1219 }
1220 #endif
1221 }
1222 }
1223
1224 /* This loop seeks out relocation sections for the data section, so
1225 that it can undo relocations performed by the runtime linker. */
1226 for (n = new_file_h->e_shnum - 1; n; n--)
1227 {
1228 ElfW(Shdr) section = NEW_SECTION_H (n);
1229
1230 /* Cause a compilation error if anyone uses n instead of nn below. */
1231 struct {int a;} n;
1232 (void)n.a; /* Prevent `unused variable' warnings. */
1233
1234 switch (section.sh_type)
1235 {
1236 default:
1237 break;
1238 case SHT_REL:
1239 case SHT_RELA:
1240 /* This code handles two different size structs, but there should
1241 be no harm in that provided that r_offset is always the first
1242 member. */
1243 nn = section.sh_info;
1244 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
1245 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1246 ".sdata")
1247 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1248 ".lit4")
1249 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1250 ".lit8")
1251 #ifdef IRIX6_5 /* see above */
1252 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1253 ".got")
1254 #endif
1255 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1256 ".sdata1")
1257 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1258 ".data1"))
1259 {
1260 ElfW(Addr) offset = (NEW_SECTION_H (nn).sh_addr
1261 - NEW_SECTION_H (nn).sh_offset);
1262 caddr_t reloc = old_base + section.sh_offset, end;
1263 for (end = reloc + section.sh_size; reloc < end;
1264 reloc += section.sh_entsize)
1265 {
1266 ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
1267 #ifdef __alpha__
1268 /* The Alpha ELF binutils currently have a bug that
1269 sometimes results in relocs that contain all
1270 zeroes. Work around this for now... */
1271 if (((ElfW(Rel) *) reloc)->r_offset == 0)
1272 continue;
1273 #endif
1274 memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
1275 }
1276 }
1277 break;
1278 }
1279 }
1280
1281 /* Write out new_file, and free the buffers. */
1282
1283 if (write (new_file, new_base, new_file_size) != new_file_size)
1284 fatal ("Didn't write %d bytes to %s: errno %d\n",
1285 new_file_size, new_name, errno);
1286 munmap (old_base, old_file_size);
1287 munmap (new_base, new_file_size);
1288
1289 /* Close the files and make the new file executable. */
1290
1291 #if MAP_ANON == 0
1292 close (mmap_fd);
1293 #endif
1294
1295 if (close (old_file))
1296 fatal ("Can't close (%s): errno %d\n", old_name, errno);
1297
1298 if (close (new_file))
1299 fatal ("Can't close (%s): errno %d\n", new_name, errno);
1300
1301 if (stat (new_name, &stat_buf) == -1)
1302 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
1303
1304 n = umask (777);
1305 umask (n);
1306 stat_buf.st_mode |= 0111 & ~n;
1307 if (chmod (new_name, stat_buf.st_mode) == -1)
1308 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
1309 }
1310