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Assume C89 or later.
[bpt/emacs.git] / src / unexelf.c
1 /* Copyright (C) 1985-1988, 1990, 1992, 1999-2012
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 #include <unexec.h>
390
391 extern void fatal (const char *msgid, ...);
392
393 #include <sys/types.h>
394 #include <stdint.h>
395 #include <stdio.h>
396 #include <sys/stat.h>
397 #include <memory.h>
398 #include <errno.h>
399 #include <unistd.h>
400 #include <fcntl.h>
401 #if !defined (__NetBSD__) && !defined (__OpenBSD__)
402 #include <elf.h>
403 #endif /* not __NetBSD__ and not __OpenBSD__ */
404 #include <sys/mman.h>
405 #if defined (_SYSTYPE_SYSV)
406 #include <sys/elf_mips.h>
407 #include <sym.h>
408 #endif /* _SYSTYPE_SYSV */
409 #if __sgi
410 #include <syms.h> /* for HDRR declaration */
411 #endif /* __sgi */
412
413 #ifndef MAP_ANON
414 #ifdef MAP_ANONYMOUS
415 #define MAP_ANON MAP_ANONYMOUS
416 #else
417 #define MAP_ANON 0
418 #endif
419 #endif
420
421 #ifndef MAP_FAILED
422 #define MAP_FAILED ((void *) -1)
423 #endif
424
425 #if defined (__alpha__) && !defined (__NetBSD__) && !defined (__OpenBSD__)
426 /* Declare COFF debugging symbol table. This used to be in
427 /usr/include/sym.h, but this file is no longer included in Red Hat
428 5.0 and presumably in any other glibc 2.x based distribution. */
429 typedef struct {
430 short magic;
431 short vstamp;
432 int ilineMax;
433 int idnMax;
434 int ipdMax;
435 int isymMax;
436 int ioptMax;
437 int iauxMax;
438 int issMax;
439 int issExtMax;
440 int ifdMax;
441 int crfd;
442 int iextMax;
443 long cbLine;
444 long cbLineOffset;
445 long cbDnOffset;
446 long cbPdOffset;
447 long cbSymOffset;
448 long cbOptOffset;
449 long cbAuxOffset;
450 long cbSsOffset;
451 long cbSsExtOffset;
452 long cbFdOffset;
453 long cbRfdOffset;
454 long cbExtOffset;
455 } HDRR, *pHDRR;
456 #define cbHDRR sizeof (HDRR)
457 #define hdrNil ((pHDRR)0)
458 #endif
459
460 #ifdef __NetBSD__
461 /*
462 * NetBSD does not have normal-looking user-land ELF support.
463 */
464 # if defined __alpha__ || defined __sparc_v9__
465 # define ELFSIZE 64
466 # else
467 # define ELFSIZE 32
468 # endif
469 # include <sys/exec_elf.h>
470
471 # ifndef PT_LOAD
472 # define PT_LOAD Elf_pt_load
473 # if 0 /* was in pkgsrc patches for 20.7 */
474 # define SHT_PROGBITS Elf_sht_progbits
475 # endif
476 # define SHT_SYMTAB Elf_sht_symtab
477 # define SHT_DYNSYM Elf_sht_dynsym
478 # define SHT_NULL Elf_sht_null
479 # define SHT_NOBITS Elf_sht_nobits
480 # define SHT_REL Elf_sht_rel
481 # define SHT_RELA Elf_sht_rela
482
483 # define SHN_UNDEF Elf_eshn_undefined
484 # define SHN_ABS Elf_eshn_absolute
485 # define SHN_COMMON Elf_eshn_common
486 # endif /* !PT_LOAD */
487
488 # ifdef __alpha__
489 # include <sys/exec_ecoff.h>
490 # define HDRR struct ecoff_symhdr
491 # define pHDRR HDRR *
492 # endif /* __alpha__ */
493
494 #ifdef __mips__ /* was in pkgsrc patches for 20.7 */
495 # define SHT_MIPS_DEBUG DT_MIPS_FLAGS
496 # define HDRR struct Elf_Shdr
497 #endif /* __mips__ */
498 #endif /* __NetBSD__ */
499
500 #ifdef __OpenBSD__
501 # include <sys/exec_elf.h>
502 #endif
503
504 #if __GNU_LIBRARY__ - 0 >= 6
505 # include <link.h> /* get ElfW etc */
506 #endif
507
508 #ifndef ElfW
509 # define ElfBitsW(bits, type) Elf##bits##_##type
510 # ifdef _LP64
511 # define ELFSIZE 64
512 # else
513 # define ELFSIZE 32
514 # endif
515 /* This macro expands `bits' before invoking ElfBitsW. */
516 # define ElfExpandBitsW(bits, type) ElfBitsW (bits, type)
517 # define ElfW(type) ElfExpandBitsW (ELFSIZE, type)
518 #endif
519
520 /* Get the address of a particular section or program header entry,
521 * accounting for the size of the entries.
522 */
523 /*
524 On PPC Reference Platform running Solaris 2.5.1
525 the plt section is also of type NOBI like the bss section.
526 (not really stored) and therefore sections after the bss
527 section start at the plt offset. The plt section is always
528 the one just before the bss section.
529 Thus, we modify the test from
530 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
531 to
532 if (NEW_SECTION_H (nn).sh_offset >=
533 OLD_SECTION_H (old_bss_index-1).sh_offset)
534 This is just a hack. We should put the new data section
535 before the .plt section.
536 And we should not have this routine at all but use
537 the libelf library to read the old file and create the new
538 file.
539 The changed code is minimal and depends on prep set in m/prep.h
540 Erik Deumens
541 Quantum Theory Project
542 University of Florida
543 deumens@qtp.ufl.edu
544 Apr 23, 1996
545 */
546
547 #define OLD_SECTION_H(n) \
548 (*(ElfW (Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
549 #define NEW_SECTION_H(n) \
550 (*(ElfW (Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
551 #define NEW_PROGRAM_H(n) \
552 (*(ElfW (Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
553
554 #define PATCH_INDEX(n) \
555 do { \
556 if ((int) (n) >= old_bss_index) \
557 (n)++; } while (0)
558 typedef unsigned char byte;
559
560 /* Round X up to a multiple of Y. */
561
562 static ElfW (Addr)
563 round_up (ElfW (Addr) x, ElfW (Addr) y)
564 {
565 int rem = x % y;
566 if (rem == 0)
567 return x;
568 return x - rem + y;
569 }
570
571 /* Return the index of the section named NAME.
572 SECTION_NAMES, FILE_NAME and FILE_H give information
573 about the file we are looking in.
574
575 If we don't find the section NAME, that is a fatal error
576 if NOERROR is 0; we return -1 if NOERROR is nonzero. */
577
578 static int
579 find_section (const char *name, const char *section_names, const char *file_name,
580 ElfW (Ehdr) *old_file_h, ElfW (Shdr) *old_section_h, int noerror)
581 {
582 int idx;
583
584 for (idx = 1; idx < old_file_h->e_shnum; idx++)
585 {
586 #ifdef DEBUG
587 fprintf (stderr, "Looking for %s - found %s\n", name,
588 section_names + OLD_SECTION_H (idx).sh_name);
589 #endif
590 if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
591 name))
592 break;
593 }
594 if (idx == old_file_h->e_shnum)
595 {
596 if (noerror)
597 return -1;
598 else
599 fatal ("Can't find %s in %s.\n", name, file_name);
600 }
601
602 return idx;
603 }
604
605 /* ****************************************************************
606 * unexec
607 *
608 * driving logic.
609 *
610 * In ELF, this works by replacing the old .bss section with a new
611 * .data section, and inserting an empty .bss immediately afterwards.
612 *
613 */
614 void
615 unexec (const char *new_name, const char *old_name)
616 {
617 int new_file, old_file, new_file_size;
618
619 #if defined (emacs) || !defined (DEBUG)
620 void *new_break;
621 #endif
622
623 /* Pointers to the base of the image of the two files. */
624 caddr_t old_base, new_base;
625
626 #if MAP_ANON == 0
627 int mmap_fd;
628 #else
629 # define mmap_fd -1
630 #endif
631
632 /* Pointers to the file, program and section headers for the old and
633 new files. */
634 ElfW (Ehdr) *old_file_h, *new_file_h;
635 ElfW (Phdr) *old_program_h, *new_program_h;
636 ElfW (Shdr) *old_section_h, *new_section_h;
637
638 /* Point to the section name table in the old file. */
639 char *old_section_names;
640
641 ElfW (Addr) old_bss_addr, new_bss_addr;
642 ElfW (Word) old_bss_size, new_data2_size;
643 ElfW (Off) new_data2_offset;
644 ElfW (Addr) new_data2_addr;
645 ElfW (Off) old_bss_offset;
646 ElfW (Word) new_data2_incr;
647
648 int n, nn;
649 int old_bss_index, old_sbss_index, old_plt_index;
650 int old_data_index, new_data2_index;
651 #if defined _SYSTYPE_SYSV || defined __sgi
652 int old_mdebug_index;
653 #endif
654 struct stat stat_buf;
655 int old_file_size;
656
657 /* Open the old file, allocate a buffer of the right size, and read
658 in the file contents. */
659
660 old_file = open (old_name, O_RDONLY);
661
662 if (old_file < 0)
663 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
664
665 if (fstat (old_file, &stat_buf) == -1)
666 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
667
668 #if MAP_ANON == 0
669 mmap_fd = open ("/dev/zero", O_RDONLY);
670 if (mmap_fd < 0)
671 fatal ("Can't open /dev/zero for reading: errno %d\n", errno, 0);
672 #endif
673
674 /* We cannot use malloc here because that may use sbrk. If it does,
675 we'd dump our temporary buffers with Emacs, and we'd have to be
676 extra careful to use the correct value of sbrk(0) after
677 allocating all buffers in the code below, which we aren't. */
678 old_file_size = stat_buf.st_size;
679 old_base = mmap (NULL, old_file_size, PROT_READ | PROT_WRITE,
680 MAP_ANON | MAP_PRIVATE, mmap_fd, 0);
681 if (old_base == MAP_FAILED)
682 fatal ("Can't allocate buffer for %s\n", old_name, 0);
683
684 if (read (old_file, old_base, stat_buf.st_size) != stat_buf.st_size)
685 fatal ("Didn't read all of %s: errno %d\n", old_name, errno);
686
687 /* Get pointers to headers & section names */
688
689 old_file_h = (ElfW (Ehdr) *) old_base;
690 old_program_h = (ElfW (Phdr) *) ((byte *) old_base + old_file_h->e_phoff);
691 old_section_h = (ElfW (Shdr) *) ((byte *) old_base + old_file_h->e_shoff);
692 old_section_names = (char *) old_base
693 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
694
695 /* Find the mdebug section, if any. */
696
697 #if defined _SYSTYPE_SYSV || defined __sgi
698 old_mdebug_index = find_section (".mdebug", old_section_names,
699 old_name, old_file_h, old_section_h, 1);
700 #endif
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_break = sbrk (0);
758 new_bss_addr = (ElfW (Addr)) new_break;
759 #else
760 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
761 #endif
762 new_data2_addr = old_bss_addr;
763 new_data2_size = new_bss_addr - old_bss_addr;
764 new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset
765 + (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
766 /* This is the amount by which the sections following the bss sections
767 must be shifted in the image. It can differ from new_data2_size if
768 the end of the old .data section (and thus the offset of the .bss
769 section) was unaligned. */
770 new_data2_incr = new_data2_size + (new_data2_offset - old_bss_offset);
771
772 #ifdef DEBUG
773 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
774 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
775 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
776 fprintf (stderr, "old_bss_offset %x\n", old_bss_offset);
777 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
778 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
779 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
780 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
781 fprintf (stderr, "new_data2_incr %x\n", new_data2_incr);
782 #endif
783
784 if ((uintptr_t) new_bss_addr < (uintptr_t) old_bss_addr + old_bss_size)
785 fatal (".bss shrank when undumping???\n", 0, 0);
786
787 /* Set the output file to the right size. Allocate a buffer to hold
788 the image of the new file. Set pointers to various interesting
789 objects. stat_buf still has old_file data. */
790
791 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
792 if (new_file < 0)
793 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
794
795 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_incr;
796
797 if (ftruncate (new_file, new_file_size))
798 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
799
800 new_base = mmap (NULL, new_file_size, PROT_READ | PROT_WRITE,
801 MAP_ANON | MAP_PRIVATE, mmap_fd, 0);
802 if (new_base == MAP_FAILED)
803 fatal ("Can't allocate buffer for %s\n", old_name, 0);
804
805 new_file_h = (ElfW (Ehdr) *) new_base;
806 new_program_h = (ElfW (Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
807 new_section_h = (ElfW (Shdr) *)
808 ((byte *) new_base + old_file_h->e_shoff + new_data2_incr);
809
810 /* Make our new file, program and section headers as copies of the
811 originals. */
812
813 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
814 memcpy (new_program_h, old_program_h,
815 old_file_h->e_phnum * old_file_h->e_phentsize);
816
817 /* Modify the e_shstrndx if necessary. */
818 PATCH_INDEX (new_file_h->e_shstrndx);
819
820 /* Fix up file header. We'll add one section. Section header is
821 further away now. */
822
823 new_file_h->e_shoff += new_data2_incr;
824 new_file_h->e_shnum += 1;
825
826 #ifdef DEBUG
827 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
828 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
829 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
830 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
831 #endif
832
833 /* Fix up a new program header. Extend the writable data segment so
834 that the bss area is covered too. Find that segment by looking
835 for a segment that ends just before the .bss area. Make sure
836 that no segments are above the new .data2. Put a loop at the end
837 to adjust the offset and address of any segment that is above
838 data2, just in case we decide to allow this later. */
839
840 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
841 {
842 /* Compute maximum of all requirements for alignment of section. */
843 ElfW (Word) alignment = (NEW_PROGRAM_H (n)).p_align;
844 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
845 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
846
847 #ifdef __sgi
848 /* According to r02kar@x4u2.desy.de (Karsten Kuenne)
849 and oliva@gnu.org (Alexandre Oliva), on IRIX 5.2, we
850 always get "Program segment above .bss" when dumping
851 when the executable doesn't have an sbss section. */
852 if (old_sbss_index != -1)
853 #endif /* __sgi */
854 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz
855 > (old_sbss_index == -1
856 ? old_bss_addr
857 : round_up (old_bss_addr, alignment)))
858 fatal ("Program segment above .bss in %s\n", old_name, 0);
859
860 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
861 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
862 + (NEW_PROGRAM_H (n)).p_filesz,
863 alignment)
864 == round_up (old_bss_addr, alignment)))
865 break;
866 }
867 if (n < 0)
868 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
869
870 /* Make sure that the size includes any padding before the old .bss
871 section. */
872 NEW_PROGRAM_H (n).p_filesz = new_bss_addr - NEW_PROGRAM_H (n).p_vaddr;
873 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
874
875 #if 0 /* Maybe allow section after data2 - does this ever happen? */
876 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
877 {
878 if (NEW_PROGRAM_H (n).p_vaddr
879 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
880 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
881
882 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
883 NEW_PROGRAM_H (n).p_offset += new_data2_incr;
884 }
885 #endif
886
887 /* Fix up section headers based on new .data2 section. Any section
888 whose offset or virtual address is after the new .data2 section
889 gets its value adjusted. .bss size becomes zero and new address
890 is set. data2 section header gets added by copying the existing
891 .data header and modifying the offset, address and size. */
892
893 /* Walk through all section headers, insert the new data2 section right
894 before the new bss section. */
895 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
896 {
897 caddr_t src;
898 /* If it is (s)bss section, insert the new data2 section before it. */
899 /* new_data2_index is the index of either old_sbss or old_bss, that was
900 chosen as a section for new_data2. */
901 if (n == new_data2_index)
902 {
903 /* Steal the data section header for this data2 section. */
904 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
905 new_file_h->e_shentsize);
906
907 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
908 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
909 NEW_SECTION_H (nn).sh_size = new_data2_size;
910 /* Use the bss section's alignment. This will assure that the
911 new data2 section always be placed in the same spot as the old
912 bss section by any other application. */
913 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
914
915 /* Now copy over what we have in the memory now. */
916 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
917 (caddr_t) OLD_SECTION_H (n).sh_addr,
918 new_data2_size);
919 nn++;
920 }
921
922 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
923 old_file_h->e_shentsize);
924
925 if (n == old_bss_index
926 /* The new bss and sbss section's size is zero, and its file offset
927 and virtual address should be off by NEW_DATA2_SIZE. */
928 || n == old_sbss_index || n == old_plt_index
929 )
930 {
931 /* NN should be `old_s?bss_index + 1' at this point. */
932 NEW_SECTION_H (nn).sh_offset = new_data2_offset + new_data2_size;
933 NEW_SECTION_H (nn).sh_addr = new_data2_addr + new_data2_size;
934 /* Let the new bss section address alignment be the same as the
935 section address alignment followed the old bss section, so
936 this section will be placed in exactly the same place. */
937 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
938 NEW_SECTION_H (nn).sh_size = 0;
939 }
940 else
941 {
942 /* Any section that was originally placed after the .bss
943 section should now be off by NEW_DATA2_INCR. If a
944 section overlaps the .bss section, consider it to be
945 placed after the .bss section. Overlap can occur if the
946 section just before .bss has less-strict alignment; this
947 was observed between .symtab and .bss on Solaris 2.5.1
948 (sparc) with GCC snapshot 960602.
949
950 > dump -h temacs
951
952 temacs:
953
954 **** SECTION HEADER TABLE ****
955 [No] Type Flags Addr Offset Size Name
956 Link Info Adralgn Entsize
957
958 [22] 1 3 0x335150 0x315150 0x4 .data.rel.local
959 0 0 0x4 0
960
961 [23] 8 3 0x335158 0x315158 0x42720 .bss
962 0 0 0x8 0
963
964 [24] 2 0 0 0x315154 0x1c9d0 .symtab
965 25 1709 0x4 0x10
966 */
967
968 if (NEW_SECTION_H (nn).sh_offset >= old_bss_offset
969 || (NEW_SECTION_H (nn).sh_offset + NEW_SECTION_H (nn).sh_size
970 > new_data2_offset))
971 NEW_SECTION_H (nn).sh_offset += new_data2_incr;
972
973 /* Any section that was originally placed after the section
974 header table should now be off by the size of one section
975 header table entry. */
976 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
977 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
978 }
979
980 /* If any section hdr refers to the section after the new .data
981 section, make it refer to next one because we have inserted
982 a new section in between. */
983
984 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
985 /* For symbol tables, info is a symbol table index,
986 so don't change it. */
987 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
988 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
989 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
990
991 if (old_sbss_index != -1)
992 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".sbss"))
993 {
994 NEW_SECTION_H (nn).sh_offset =
995 round_up (NEW_SECTION_H (nn).sh_offset,
996 NEW_SECTION_H (nn).sh_addralign);
997 NEW_SECTION_H (nn).sh_type = SHT_PROGBITS;
998 }
999
1000 /* Now, start to copy the content of sections. */
1001 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
1002 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
1003 continue;
1004
1005 /* Write out the sections. .data and .data1 (and data2, called
1006 ".data" in the strings table) get copied from the current process
1007 instead of the old file. */
1008 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
1009 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1010 ".sdata")
1011 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1012 ".lit4")
1013 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1014 ".lit8")
1015 /* The conditional bit below was in Oliva's original code
1016 (1999-08-25) and seems to have been dropped by mistake
1017 subsequently. It prevents a crash at startup under X in
1018 `IRIX64 6.5 6.5.17m', whether compiled on that release or
1019 an earlier one. It causes no trouble on the other ELF
1020 platforms I could test (Irix 6.5.15m, Solaris 8, Debian
1021 Potato x86, Debian Woody SPARC); however, it's reported
1022 to cause crashes under some version of GNU/Linux. It's
1023 not yet clear what's changed in that Irix version to
1024 cause the problem, or why the fix sometimes fails under
1025 GNU/Linux. There's probably no good reason to have
1026 something Irix-specific here, but this will have to do
1027 for now. IRIX6_5 is the most specific macro we have to
1028 test. -- fx 2002-10-01
1029
1030 The issue _looks_ as though it's gone away on 6.5.18m,
1031 but maybe it's still lurking, to be triggered by some
1032 change in the binary. It appears to concern the dynamic
1033 loader, but I never got anywhere with an SGI support call
1034 seeking clues. -- fx 2002-11-29. */
1035 #ifdef IRIX6_5
1036 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1037 ".got")
1038 #endif
1039 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1040 ".sdata1")
1041 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1042 ".data1")
1043 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1044 ".sbss"))
1045 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
1046 else
1047 src = old_base + OLD_SECTION_H (n).sh_offset;
1048
1049 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
1050 NEW_SECTION_H (nn).sh_size);
1051
1052 #if defined __alpha__ && !defined __OpenBSD__
1053 /* Update Alpha COFF symbol table: */
1054 if (strcmp (old_section_names + OLD_SECTION_H (n).sh_name, ".mdebug")
1055 == 0)
1056 {
1057 pHDRR symhdr = (pHDRR) (NEW_SECTION_H (nn).sh_offset + new_base);
1058
1059 symhdr->cbLineOffset += new_data2_size;
1060 symhdr->cbDnOffset += new_data2_size;
1061 symhdr->cbPdOffset += new_data2_size;
1062 symhdr->cbSymOffset += new_data2_size;
1063 symhdr->cbOptOffset += new_data2_size;
1064 symhdr->cbAuxOffset += new_data2_size;
1065 symhdr->cbSsOffset += new_data2_size;
1066 symhdr->cbSsExtOffset += new_data2_size;
1067 symhdr->cbFdOffset += new_data2_size;
1068 symhdr->cbRfdOffset += new_data2_size;
1069 symhdr->cbExtOffset += new_data2_size;
1070 }
1071 #endif /* __alpha__ && !__OpenBSD__ */
1072
1073 #if defined (_SYSTYPE_SYSV)
1074 if (NEW_SECTION_H (nn).sh_type == SHT_MIPS_DEBUG
1075 && old_mdebug_index != -1)
1076 {
1077 int diff = NEW_SECTION_H (nn).sh_offset
1078 - OLD_SECTION_H (old_mdebug_index).sh_offset;
1079 HDRR *phdr = (HDRR *)(NEW_SECTION_H (nn).sh_offset + new_base);
1080
1081 if (diff)
1082 {
1083 phdr->cbLineOffset += diff;
1084 phdr->cbDnOffset += diff;
1085 phdr->cbPdOffset += diff;
1086 phdr->cbSymOffset += diff;
1087 phdr->cbOptOffset += diff;
1088 phdr->cbAuxOffset += diff;
1089 phdr->cbSsOffset += diff;
1090 phdr->cbSsExtOffset += diff;
1091 phdr->cbFdOffset += diff;
1092 phdr->cbRfdOffset += diff;
1093 phdr->cbExtOffset += diff;
1094 }
1095 }
1096 #endif /* _SYSTYPE_SYSV */
1097
1098 #if __sgi
1099 /* Adjust the HDRR offsets in .mdebug and copy the
1100 line data if it's in its usual 'hole' in the object.
1101 Makes the new file debuggable with dbx.
1102 patches up two problems: the absolute file offsets
1103 in the HDRR record of .mdebug (see /usr/include/syms.h), and
1104 the ld bug that gets the line table in a hole in the
1105 elf file rather than in the .mdebug section proper.
1106 David Anderson. davea@sgi.com Jan 16,1994. */
1107 if (n == old_mdebug_index)
1108 {
1109 #define MDEBUGADJUST(__ct,__fileaddr) \
1110 if (n_phdrr->__ct > 0) \
1111 { \
1112 n_phdrr->__fileaddr += movement; \
1113 }
1114
1115 HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset);
1116 HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset);
1117 unsigned movement = new_data2_size;
1118
1119 MDEBUGADJUST (idnMax, cbDnOffset);
1120 MDEBUGADJUST (ipdMax, cbPdOffset);
1121 MDEBUGADJUST (isymMax, cbSymOffset);
1122 MDEBUGADJUST (ioptMax, cbOptOffset);
1123 MDEBUGADJUST (iauxMax, cbAuxOffset);
1124 MDEBUGADJUST (issMax, cbSsOffset);
1125 MDEBUGADJUST (issExtMax, cbSsExtOffset);
1126 MDEBUGADJUST (ifdMax, cbFdOffset);
1127 MDEBUGADJUST (crfd, cbRfdOffset);
1128 MDEBUGADJUST (iextMax, cbExtOffset);
1129 /* The Line Section, being possible off in a hole of the object,
1130 requires special handling. */
1131 if (n_phdrr->cbLine > 0)
1132 {
1133 if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset
1134 + OLD_SECTION_H (n).sh_size))
1135 {
1136 /* line data is in a hole in elf. do special copy and adjust
1137 for this ld mistake.
1138 */
1139 n_phdrr->cbLineOffset += movement;
1140
1141 memcpy (n_phdrr->cbLineOffset + new_base,
1142 o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
1143 }
1144 else
1145 {
1146 /* somehow line data is in .mdebug as it is supposed to be. */
1147 MDEBUGADJUST (cbLine, cbLineOffset);
1148 }
1149 }
1150 }
1151 #endif /* __sgi */
1152
1153 /* If it is the symbol table, its st_shndx field needs to be patched. */
1154 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
1155 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
1156 {
1157 ElfW (Shdr) *spt = &NEW_SECTION_H (nn);
1158 unsigned int num = spt->sh_size / spt->sh_entsize;
1159 ElfW (Sym) * sym = (ElfW (Sym) *) (NEW_SECTION_H (nn).sh_offset +
1160 new_base);
1161 for (; num--; sym++)
1162 {
1163 if ((sym->st_shndx == SHN_UNDEF)
1164 || (sym->st_shndx == SHN_ABS)
1165 || (sym->st_shndx == SHN_COMMON))
1166 continue;
1167
1168 PATCH_INDEX (sym->st_shndx);
1169 }
1170 }
1171 }
1172
1173 /* Update the symbol values of _edata and _end. */
1174 for (n = new_file_h->e_shnum - 1; n; n--)
1175 {
1176 byte *symnames;
1177 ElfW (Sym) *symp, *symendp;
1178
1179 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
1180 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
1181 continue;
1182
1183 symnames = ((byte *) new_base
1184 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
1185 symp = (ElfW (Sym) *) (NEW_SECTION_H (n).sh_offset + new_base);
1186 symendp = (ElfW (Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
1187
1188 for (; symp < symendp; symp ++)
1189 {
1190 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
1191 || strcmp ((char *) (symnames + symp->st_name), "end") == 0
1192 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0
1193 || strcmp ((char *) (symnames + symp->st_name), "edata") == 0)
1194 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
1195
1196 /* Strictly speaking, #ifdef below is not necessary. But we
1197 keep it to indicate that this kind of change may also be
1198 necessary for other unexecs to support GNUstep. */
1199 #ifdef NS_IMPL_GNUSTEP
1200 /* ObjC runtime modifies the values of some data structures
1201 such as classes and selectors in the .data section after
1202 loading. As the dump process copies the .data section
1203 from the current process, that causes problems when the
1204 modified classes are reinitialized in the dumped
1205 executable. We copy such data from the old file, not
1206 from the current process. */
1207 if (strncmp ((char *) (symnames + symp->st_name),
1208 "_OBJC_", sizeof ("_OBJC_") - 1) == 0)
1209 {
1210 caddr_t old, new;
1211
1212 new = ((symp->st_value - NEW_SECTION_H (symp->st_shndx).sh_addr)
1213 + NEW_SECTION_H (symp->st_shndx).sh_offset + new_base);
1214 /* "Unpatch" index. */
1215 nn = symp->st_shndx;
1216 if (nn > old_bss_index)
1217 nn--;
1218 if (nn == old_bss_index)
1219 memset (new, 0, symp->st_size);
1220 else
1221 {
1222 old = ((symp->st_value
1223 - NEW_SECTION_H (symp->st_shndx).sh_addr)
1224 + OLD_SECTION_H (nn).sh_offset + old_base);
1225 memcpy (new, old, symp->st_size);
1226 }
1227 }
1228 #endif
1229 }
1230 }
1231
1232 /* This loop seeks out relocation sections for the data section, so
1233 that it can undo relocations performed by the runtime linker. */
1234 for (n = new_file_h->e_shnum - 1; n; n--)
1235 {
1236 ElfW (Shdr) section = NEW_SECTION_H (n);
1237
1238 /* Cause a compilation error if anyone uses n instead of nn below. */
1239 #define n ((void) 0);
1240 n /* Prevent 'macro "n" is not used' warnings. */
1241
1242 switch (section.sh_type)
1243 {
1244 default:
1245 break;
1246 case SHT_REL:
1247 case SHT_RELA:
1248 /* This code handles two different size structs, but there should
1249 be no harm in that provided that r_offset is always the first
1250 member. */
1251 nn = section.sh_info;
1252 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
1253 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1254 ".sdata")
1255 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1256 ".lit4")
1257 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1258 ".lit8")
1259 #ifdef IRIX6_5 /* see above */
1260 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1261 ".got")
1262 #endif
1263 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1264 ".sdata1")
1265 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1266 ".data1"))
1267 {
1268 ElfW (Addr) offset = (NEW_SECTION_H (nn).sh_addr
1269 - NEW_SECTION_H (nn).sh_offset);
1270 caddr_t reloc = old_base + section.sh_offset, end;
1271 for (end = reloc + section.sh_size; reloc < end;
1272 reloc += section.sh_entsize)
1273 {
1274 ElfW (Addr) addr = ((ElfW (Rel) *) reloc)->r_offset - offset;
1275 #ifdef __alpha__
1276 /* The Alpha ELF binutils currently have a bug that
1277 sometimes results in relocs that contain all
1278 zeroes. Work around this for now... */
1279 if (((ElfW (Rel) *) reloc)->r_offset == 0)
1280 continue;
1281 #endif
1282 memcpy (new_base + addr, old_base + addr, sizeof (ElfW (Addr)));
1283 }
1284 }
1285 break;
1286 }
1287
1288 #undef n
1289 }
1290
1291 /* Write out new_file, and free the buffers. */
1292
1293 if (write (new_file, new_base, new_file_size) != new_file_size)
1294 fatal ("Didn't write %d bytes to %s: errno %d\n",
1295 new_file_size, new_name, errno);
1296 munmap (old_base, old_file_size);
1297 munmap (new_base, new_file_size);
1298
1299 /* Close the files and make the new file executable. */
1300
1301 #if MAP_ANON == 0
1302 close (mmap_fd);
1303 #endif
1304
1305 if (close (old_file))
1306 fatal ("Can't close (%s): errno %d\n", old_name, errno);
1307
1308 if (close (new_file))
1309 fatal ("Can't close (%s): errno %d\n", new_name, errno);
1310
1311 if (stat (new_name, &stat_buf) == -1)
1312 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
1313
1314 n = umask (777);
1315 umask (n);
1316 stat_buf.st_mode |= 0111 & ~n;
1317 if (chmod (new_name, stat_buf.st_mode) == -1)
1318 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
1319 }
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