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comparison src/unexelf.c @ 0:376386a54a3c r19-14

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date Mon, 13 Aug 2007 08:45:50 +0200
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1 /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992, 1993
2 Free Software Foundation, Inc.
3
4 This file is part of XEmacs.
5
6 XEmacs is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
9 later version.
10
11 XEmacs is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with XEmacs; see the file COPYING. If not, write to
18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
20
21 /* Synched up with: FSF 19.31. */
22
23 /*
24 * unexec.c - Convert a running program into an a.out file.
25 *
26 * Author: Spencer W. Thomas
27 * Computer Science Dept.
28 * University of Utah
29 * Date: Tue Mar 2 1982
30 * Modified heavily since then.
31 *
32 * Synopsis:
33 * unexec (new_name, a_name, data_start, bss_start, entry_address)
34 * char *new_name, *a_name;
35 * unsigned data_start, bss_start, entry_address;
36 *
37 * Takes a snapshot of the program and makes an a.out format file in the
38 * file named by the string argument new_name.
39 * If a_name is non-NULL, the symbol table will be taken from the given file.
40 * On some machines, an existing a_name file is required.
41 *
42 * The boundaries within the a.out file may be adjusted with the data_start
43 * and bss_start arguments. Either or both may be given as 0 for defaults.
44 *
45 * Data_start gives the boundary between the text segment and the data
46 * segment of the program. The text segment can contain shared, read-only
47 * program code and literal data, while the data segment is always unshared
48 * and unprotected. Data_start gives the lowest unprotected address.
49 * The value you specify may be rounded down to a suitable boundary
50 * as required by the machine you are using.
51 *
52 * Specifying zero for data_start means the boundary between text and data
53 * should not be the same as when the program was loaded.
54 * If NO_REMAP is defined, the argument data_start is ignored and the
55 * segment boundaries are never changed.
56 *
57 * Bss_start indicates how much of the data segment is to be saved in the
58 * a.out file and restored when the program is executed. It gives the lowest
59 * unsaved address, and is rounded up to a page boundary. The default when 0
60 * is given assumes that the entire data segment is to be stored, including
61 * the previous data and bss as well as any additional storage allocated with
62 * break (2).
63 *
64 * The new file is set up to start at entry_address.
65 *
66 * If you make improvements I'd like to get them too.
67 * harpo!utah-cs!thomas, thomas@Utah-20
68 *
69 */
70
71 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
72 * ELF support added.
73 *
74 * Basic theory: the data space of the running process needs to be
75 * dumped to the output file. Normally we would just enlarge the size
76 * of .data, scooting everything down. But we can't do that in ELF,
77 * because there is often something between the .data space and the
78 * .bss space.
79 *
80 * In the temacs dump below, notice that the Global Offset Table
81 * (.got) and the Dynamic link data (.dynamic) come between .data1 and
82 * .bss. It does not work to overlap .data with these fields.
83 *
84 * The solution is to create a new .data segment. This segment is
85 * filled with data from the current process. Since the contents of
86 * various sections refer to sections by index, the new .data segment
87 * is made the last in the table to avoid changing any existing index.
88
89 * This is an example of how the section headers are changed. "Addr"
90 * is a process virtual address. "Offset" is a file offset.
91
92 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
93
94 temacs:
95
96 **** SECTION HEADER TABLE ****
97 [No] Type Flags Addr Offset Size Name
98 Link Info Adralgn Entsize
99
100 [1] 1 2 0x80480d4 0xd4 0x13 .interp
101 0 0 0x1 0
102
103 [2] 5 2 0x80480e8 0xe8 0x388 .hash
104 3 0 0x4 0x4
105
106 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
107 4 1 0x4 0x10
108
109 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
110 0 0 0x1 0
111
112 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
113 3 7 0x4 0x8
114
115 [6] 1 6 0x8049348 0x1348 0x3 .init
116 0 0 0x4 0
117
118 [7] 1 6 0x804934c 0x134c 0x680 .plt
119 0 0 0x4 0x4
120
121 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
122 0 0 0x4 0
123
124 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
125 0 0 0x4 0
126
127 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
128 0 0 0x4 0
129
130 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
131 0 0 0x4 0
132
133 [12] 1 3 0x8088330 0x3f330 0x20afc .data
134 0 0 0x4 0
135
136 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
137 0 0 0x4 0
138
139 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
140 0 0 0x4 0x4
141
142 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
143 4 0 0x4 0x8
144
145 [16] 8 3 0x80a98f4 0x608f4 0x449c .bss
146 0 0 0x4 0
147
148 [17] 2 0 0 0x608f4 0x9b90 .symtab
149 18 371 0x4 0x10
150
151 [18] 3 0 0 0x6a484 0x8526 .strtab
152 0 0 0x1 0
153
154 [19] 3 0 0 0x729aa 0x93 .shstrtab
155 0 0 0x1 0
156
157 [20] 1 0 0 0x72a3d 0x68b7 .comment
158 0 0 0x1 0
159
160 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
161
162 xemacs:
163
164 **** SECTION HEADER TABLE ****
165 [No] Type Flags Addr Offset Size Name
166 Link Info Adralgn Entsize
167
168 [1] 1 2 0x80480d4 0xd4 0x13 .interp
169 0 0 0x1 0
170
171 [2] 5 2 0x80480e8 0xe8 0x388 .hash
172 3 0 0x4 0x4
173
174 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
175 4 1 0x4 0x10
176
177 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
178 0 0 0x1 0
179
180 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
181 3 7 0x4 0x8
182
183 [6] 1 6 0x8049348 0x1348 0x3 .init
184 0 0 0x4 0
185
186 [7] 1 6 0x804934c 0x134c 0x680 .plt
187 0 0 0x4 0x4
188
189 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
190 0 0 0x4 0
191
192 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
193 0 0 0x4 0
194
195 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
196 0 0 0x4 0
197
198 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
199 0 0 0x4 0
200
201 [12] 1 3 0x8088330 0x3f330 0x20afc .data
202 0 0 0x4 0
203
204 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
205 0 0 0x4 0
206
207 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
208 0 0 0x4 0x4
209
210 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
211 4 0 0x4 0x8
212
213 [16] 8 3 0x80c6800 0x7d800 0 .bss
214 0 0 0x4 0
215
216 [17] 2 0 0 0x7d800 0x9b90 .symtab
217 18 371 0x4 0x10
218
219 [18] 3 0 0 0x87390 0x8526 .strtab
220 0 0 0x1 0
221
222 [19] 3 0 0 0x8f8b6 0x93 .shstrtab
223 0 0 0x1 0
224
225 [20] 1 0 0 0x8f949 0x68b7 .comment
226 0 0 0x1 0
227
228 [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
229 0 0 0x4 0
230
231 * This is an example of how the file header is changed. "Shoff" is
232 * the section header offset within the file. Since that table is
233 * after the new .data section, it is moved. "Shnum" is the number of
234 * sections, which we increment.
235 *
236 * "Phoff" is the file offset to the program header. "Phentsize" and
237 * "Shentsz" are the program and section header entries sizes respectively.
238 * These can be larger than the apparent struct sizes.
239
240 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
241
242 temacs:
243
244 **** ELF HEADER ****
245 Class Data Type Machine Version
246 Entry Phoff Shoff Flags Ehsize
247 Phentsize Phnum Shentsz Shnum Shstrndx
248
249 1 1 2 3 1
250 0x80499cc 0x34 0x792f4 0 0x34
251 0x20 5 0x28 21 19
252
253 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
254
255 xemacs:
256
257 **** ELF HEADER ****
258 Class Data Type Machine Version
259 Entry Phoff Shoff Flags Ehsize
260 Phentsize Phnum Shentsz Shnum Shstrndx
261
262 1 1 2 3 1
263 0x80499cc 0x34 0x96200 0 0x34
264 0x20 5 0x28 22 19
265
266 * These are the program headers. "Offset" is the file offset to the
267 * segment. "Vaddr" is the memory load address. "Filesz" is the
268 * segment size as it appears in the file, and "Memsz" is the size in
269 * memory. Below, the third segment is the code and the fourth is the
270 * data: the difference between Filesz and Memsz is .bss
271
272 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
273
274 temacs:
275 ***** PROGRAM EXECUTION HEADER *****
276 Type Offset Vaddr Paddr
277 Filesz Memsz Flags Align
278
279 6 0x34 0x8048034 0
280 0xa0 0xa0 5 0
281
282 3 0xd4 0 0
283 0x13 0 4 0
284
285 1 0x34 0x8048034 0
286 0x3f2f9 0x3f2f9 5 0x1000
287
288 1 0x3f330 0x8088330 0
289 0x215c4 0x25a60 7 0x1000
290
291 2 0x60874 0x80a9874 0
292 0x80 0 7 0
293
294 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
295
296 xemacs:
297 ***** PROGRAM EXECUTION HEADER *****
298 Type Offset Vaddr Paddr
299 Filesz Memsz Flags Align
300
301 6 0x34 0x8048034 0
302 0xa0 0xa0 5 0
303
304 3 0xd4 0 0
305 0x13 0 4 0
306
307 1 0x34 0x8048034 0
308 0x3f2f9 0x3f2f9 5 0x1000
309
310 1 0x3f330 0x8088330 0
311 0x3e4d0 0x3e4d0 7 0x1000
312
313 2 0x60874 0x80a9874 0
314 0x80 0 7 0
315
316
317 */
318
319 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
320 *
321 * The above mechanism does not work if the unexeced ELF file is being
322 * re-layout by other applications (such as `strip'). All the applications
323 * that re-layout the internal of ELF will layout all sections in ascending
324 * order of their file offsets. After the re-layout, the data2 section will
325 * still be the LAST section in the section header vector, but its file offset
326 * is now being pushed far away down, and causes part of it not to be mapped
327 * in (ie. not covered by the load segment entry in PHDR vector), therefore
328 * causes the new binary to fail.
329 *
330 * The solution is to modify the unexec algorithm to insert the new data2
331 * section header right before the new bss section header, so their file
332 * offsets will be in the ascending order. Since some of the section's (all
333 * sections AFTER the bss section) indexes are now changed, we also need to
334 * modify some fields to make them point to the right sections. This is done
335 * by macro PATCH_INDEX. All the fields that need to be patched are:
336 *
337 * 1. ELF header e_shstrndx field.
338 * 2. section header sh_link and sh_info field.
339 * 3. symbol table entry st_shndx field.
340 *
341 * The above example now should look like:
342
343 **** SECTION HEADER TABLE ****
344 [No] Type Flags Addr Offset Size Name
345 Link Info Adralgn Entsize
346
347 [1] 1 2 0x80480d4 0xd4 0x13 .interp
348 0 0 0x1 0
349
350 [2] 5 2 0x80480e8 0xe8 0x388 .hash
351 3 0 0x4 0x4
352
353 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
354 4 1 0x4 0x10
355
356 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
357 0 0 0x1 0
358
359 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
360 3 7 0x4 0x8
361
362 [6] 1 6 0x8049348 0x1348 0x3 .init
363 0 0 0x4 0
364
365 [7] 1 6 0x804934c 0x134c 0x680 .plt
366 0 0 0x4 0x4
367
368 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
369 0 0 0x4 0
370
371 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
372 0 0 0x4 0
373
374 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
375 0 0 0x4 0
376
377 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
378 0 0 0x4 0
379
380 [12] 1 3 0x8088330 0x3f330 0x20afc .data
381 0 0 0x4 0
382
383 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
384 0 0 0x4 0
385
386 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
387 0 0 0x4 0x4
388
389 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
390 4 0 0x4 0x8
391
392 [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
393 0 0 0x4 0
394
395 [17] 8 3 0x80c6800 0x7d800 0 .bss
396 0 0 0x4 0
397
398 [18] 2 0 0 0x7d800 0x9b90 .symtab
399 19 371 0x4 0x10
400
401 [19] 3 0 0 0x87390 0x8526 .strtab
402 0 0 0x1 0
403
404 [20] 3 0 0 0x8f8b6 0x93 .shstrtab
405 0 0 0x1 0
406
407 [21] 1 0 0 0x8f949 0x68b7 .comment
408 0 0 0x1 0
409
410 */
411
412 #include <sys/types.h>
413 #include <stdio.h>
414 #include <sys/stat.h>
415 #include <memory.h>
416 #include <string.h>
417 #include <errno.h>
418 #include <unistd.h>
419 #include <fcntl.h>
420 #include <elf.h>
421 #include <sys/mman.h>
422
423 #ifndef emacs
424 #define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1)
425 #else
426 #include <config.h>
427 extern void fatal (char *, ...);
428 #endif
429
430 #ifndef ELF_BSS_SECTION_NAME
431 #define ELF_BSS_SECTION_NAME ".bss"
432 #endif
433
434 /* Get the address of a particular section or program header entry,
435 * accounting for the size of the entries.
436 */
437 /*
438 On PPC Reference Platform running Solaris 2.5.1
439 the plt section is also of type NOBI like the bss section.
440 (not really stored) and therefore sections after the bss
441 section start at the plt offset. The plt section is always
442 the one just before the bss section.
443 Thus, we modify the test from
444 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
445 to
446 if (NEW_SECTION_H (nn).sh_offset >=
447 OLD_SECTION_H (old_bss_index-1).sh_offset)
448 This is just a hack. We should put the new data section
449 before the .plt section.
450 And we should not have this routine at all but use
451 the libelf library to read the old file and create the new
452 file.
453 The changed code is minimal and depends on prep set in m/prep.h
454 Erik Deumens
455 Quantum Theory Project
456 University of Florida
457 deumens@qtp.ufl.edu
458 Apr 23, 1996
459 */
460
461 #define OLD_SECTION_H(n) \
462 (*(Elf32_Shdr *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
463 #define NEW_SECTION_H(n) \
464 (*(Elf32_Shdr *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
465 #define OLD_PROGRAM_H(n) \
466 (*(Elf32_Phdr *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
467 #define NEW_PROGRAM_H(n) \
468 (*(Elf32_Phdr *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
469
470 #define PATCH_INDEX(n) \
471 do { \
472 if ((int) (n) >= old_bss_index) \
473 (n)++; } while (0)
474 typedef unsigned char byte;
475
476 /* Round X up to a multiple of Y. */
477
478 static int
479 round_up (int x, int y)
480 {
481 int rem = x % y;
482 if (rem == 0)
483 return x;
484 return x - rem + y;
485 }
486
487 /* ****************************************************************
488 * unexec
489 *
490 * driving logic.
491 *
492 * In ELF, this works by replacing the old .bss section with a new
493 * .data section, and inserting an empty .bss immediately afterwards.
494 *
495 */
496 void unexec (char *new_name, char *old_name, unsigned int data_start,
497 unsigned int bss_start, unsigned int entry_address);
498 void
499 unexec (char *new_name, char *old_name, unsigned int data_start,
500 unsigned int bss_start, unsigned int entry_address)
501 {
502 int new_file, old_file, new_file_size;
503
504 /* Pointers to the base of the image of the two files. */
505 caddr_t old_base, new_base;
506
507 /* Pointers to the file, program and section headers for the old and new
508 * files.
509 */
510 Elf32_Ehdr *old_file_h, *new_file_h;
511 Elf32_Phdr *old_program_h, *new_program_h;
512 Elf32_Shdr *old_section_h, *new_section_h;
513
514 /* Point to the section name table in the old file */
515 char *old_section_names;
516
517 Elf32_Addr old_bss_addr, new_bss_addr;
518 Elf32_Word old_bss_size, new_data2_size;
519 Elf32_Off new_data2_offset;
520 Elf32_Addr new_data2_addr;
521
522 int n, nn, old_bss_index, old_data_index;
523 struct stat stat_buf;
524
525 /* Open the old file & map it into the address space. */
526
527 old_file = open (old_name, O_RDONLY);
528
529 if (old_file < 0)
530 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
531
532 if (fstat (old_file, &stat_buf) == -1)
533 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
534
535 old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0);
536
537 if (old_base == (caddr_t) -1)
538 fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
539
540 #ifdef DEBUG
541 fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size,
542 old_base);
543 #endif
544
545 /* Get pointers to headers & section names */
546
547 old_file_h = (Elf32_Ehdr *) old_base;
548 old_program_h = (Elf32_Phdr *) ((byte *) old_base + old_file_h->e_phoff);
549 old_section_h = (Elf32_Shdr *) ((byte *) old_base + old_file_h->e_shoff);
550 old_section_names = (char *) old_base
551 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
552
553 /* Find the old .bss section. Figure out parameters of the new
554 * data2 and bss sections.
555 */
556
557 for (old_bss_index = 1; old_bss_index < (int) old_file_h->e_shnum;
558 old_bss_index++)
559 {
560 #ifdef DEBUG
561 fprintf (stderr, "Looking for .bss - found %s\n",
562 old_section_names + OLD_SECTION_H (old_bss_index).sh_name);
563 #endif
564 if (!strcmp (old_section_names + OLD_SECTION_H (old_bss_index).sh_name,
565 ELF_BSS_SECTION_NAME))
566 break;
567 }
568 if (old_bss_index == old_file_h->e_shnum)
569 fatal ("Can't find .bss in %s.\n", old_name, 0);
570
571 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
572 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
573 #if defined(emacs) || !defined(DEBUG)
574 new_bss_addr = (Elf32_Addr) sbrk (0);
575 #else
576 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
577 #endif
578 new_data2_addr = old_bss_addr;
579 new_data2_size = new_bss_addr - old_bss_addr;
580 new_data2_offset = OLD_SECTION_H (old_bss_index).sh_offset;
581
582 #ifdef DEBUG
583 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
584 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
585 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
586 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
587 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
588 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
589 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
590 #endif
591
592 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
593 fatal (".bss shrank when undumping???\n", 0, 0);
594
595 /* Set the output file to the right size and mmap it. Set
596 * pointers to various interesting objects. stat_buf still has
597 * old_file data.
598 */
599
600 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
601 if (new_file < 0)
602 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
603
604 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size;
605
606 if (ftruncate (new_file, new_file_size))
607 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
608
609 #ifdef UNEXEC_USE_MAP_PRIVATE
610 new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
611 new_file, 0);
612 #else
613 new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED,
614 new_file, 0);
615 #endif
616
617 if (new_base == (caddr_t) -1)
618 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
619
620 new_file_h = (Elf32_Ehdr *) new_base;
621 new_program_h = (Elf32_Phdr *) ((byte *) new_base + old_file_h->e_phoff);
622 new_section_h = (Elf32_Shdr *)
623 ((byte *) new_base + old_file_h->e_shoff + new_data2_size);
624
625 /* Make our new file, program and section headers as copies of the
626 * originals.
627 */
628
629 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
630 memcpy (new_program_h, old_program_h,
631 old_file_h->e_phnum * old_file_h->e_phentsize);
632
633 /* Modify the e_shstrndx if necessary. */
634 PATCH_INDEX (new_file_h->e_shstrndx);
635
636 /* Fix up file header. We'll add one section. Section header is
637 * further away now.
638 */
639
640 new_file_h->e_shoff += new_data2_size;
641 new_file_h->e_shnum += 1;
642
643 #ifdef DEBUG
644 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
645 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
646 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
647 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
648 #endif
649
650 /* Fix up a new program header. Extend the writable data segment so
651 * that the bss area is covered too. Find that segment by looking
652 * for a segment that ends just before the .bss area. Make sure
653 * that no segments are above the new .data2. Put a loop at the end
654 * to adjust the offset and address of any segment that is above
655 * data2, just in case we decide to allow this later.
656 */
657
658 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
659 {
660 /* Compute maximum of all requirements for alignment of section. */
661 int alignment = (NEW_PROGRAM_H (n)).p_align;
662 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
663 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
664
665 #ifndef __mips /* ifndef added by jwz at suggestion of
666 r02kar@x4u2.desy.de (Karsten Kuenne) to avoid
667 "Program segment above .bss" when dumping.
668 */
669 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr)
670 fatal ("Program segment above .bss in %s\n", old_name, 0);
671 #endif /* __mips */
672
673 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
674 && (round_up ((int) ((NEW_PROGRAM_H (n)).p_vaddr
675 + (NEW_PROGRAM_H (n)).p_filesz),
676 alignment)
677 == round_up ((int) old_bss_addr, alignment)))
678 break;
679 }
680 if (n < 0)
681 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
682
683 NEW_PROGRAM_H (n).p_filesz += new_data2_size;
684 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
685
686 #if 0 /* Maybe allow section after data2 - does this ever happen? */
687 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
688 {
689 if (NEW_PROGRAM_H (n).p_vaddr
690 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
691 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
692
693 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
694 NEW_PROGRAM_H (n).p_offset += new_data2_size;
695 }
696 #endif
697
698 /* Fix up section headers based on new .data2 section. Any section
699 * whose offset or virtual address is after the new .data2 section
700 * gets its value adjusted. .bss size becomes zero and new address
701 * is set. data2 section header gets added by copying the existing
702 * .data header and modifying the offset, address and size.
703 */
704 for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum;
705 old_data_index++)
706 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
707 ".data"))
708 break;
709 if (old_data_index == old_file_h->e_shnum)
710 fatal ("Can't find .data in %s.\n", old_name, 0);
711
712 /* Walk through all section headers, insert the new data2 section right
713 before the new bss section. */
714 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
715 {
716 caddr_t src;
717 /* If it is bss section, insert the new data2 section before it. */
718 if (n == old_bss_index)
719 {
720 /* Steal the data section header for this data2 section. */
721 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
722 new_file_h->e_shentsize);
723
724 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
725 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
726 NEW_SECTION_H (nn).sh_size = new_data2_size;
727 /* Use the bss section's alignment. This will assure that the
728 new data2 section always be placed in the same spot as the old
729 bss section by any other application. */
730 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
731
732 /* Now copy over what we have in the memory now. */
733 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
734 (caddr_t) OLD_SECTION_H (n).sh_addr,
735 new_data2_size);
736 nn++;
737 }
738
739 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
740 old_file_h->e_shentsize);
741
742 /* The new bss section's size is zero, and its file offset and virtual
743 address should be off by NEW_DATA2_SIZE. */
744 if (n == old_bss_index)
745 {
746 /* NN should be `old_bss_index + 1' at this point. */
747 NEW_SECTION_H (nn).sh_offset += new_data2_size;
748 NEW_SECTION_H (nn).sh_addr += new_data2_size;
749 /* Let the new bss section address alignment be the same as the
750 section address alignment followed the old bss section, so
751 this section will be placed in exactly the same place. */
752 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
753 NEW_SECTION_H (nn).sh_size = 0;
754 }
755 else
756 {
757 /* Any section that was original placed AFTER the bss
758 section should now be off by NEW_DATA2_SIZE. */
759 #ifdef SOLARIS_POWERPC
760 /* On PPC Reference Platform running Solaris 2.5.1
761 the plt section is also of type NOBI like the bss section.
762 (not really stored) and therefore sections after the bss
763 section start at the plt offset. The plt section is always
764 the one just before the bss section.
765 It would be better to put the new data section before
766 the .plt section, or use libelf instead.
767 Erik Deumens, deumens@qtp.ufl.edu. */
768 if (NEW_SECTION_H (nn).sh_offset
769 >= OLD_SECTION_H (old_bss_index-1).sh_offset)
770 NEW_SECTION_H (nn).sh_offset += new_data2_size;
771 #else
772 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
773 NEW_SECTION_H (nn).sh_offset += new_data2_size;
774 #endif
775 /* Any section that was originally placed after the section
776 header table should now be off by the size of one section
777 header table entry. */
778 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
779 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
780 }
781
782 /* If any section hdr refers to the section after the new .data
783 section, make it refer to next one because we have inserted
784 a new section in between. */
785
786 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
787 /* For symbol tables, info is a symbol table index,
788 so don't change it. */
789 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
790 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
791 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
792
793 /* Now, start to copy the content of sections. */
794 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
795 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
796 continue;
797
798 /* Write out the sections. .data and .data1 (and data2, called
799 ".data" in the strings table) get copied from the current process
800 instead of the old file. */
801 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
802 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
803 ".data1"))
804 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
805 else
806 src = old_base + OLD_SECTION_H (n).sh_offset;
807
808 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
809 NEW_SECTION_H (nn).sh_size);
810
811 /* If it is the symbol table, its st_shndx field needs to be patched. */
812 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
813 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
814 {
815 Elf32_Shdr *spt = &NEW_SECTION_H (nn);
816 unsigned int num = spt->sh_size / spt->sh_entsize;
817 Elf32_Sym * sym = (Elf32_Sym *) (NEW_SECTION_H (nn).sh_offset +
818 new_base);
819 for (; num--; sym++)
820 {
821 if ((sym->st_shndx == SHN_UNDEF)
822 || (sym->st_shndx == SHN_ABS)
823 || (sym->st_shndx == SHN_COMMON))
824 continue;
825
826 PATCH_INDEX (sym->st_shndx);
827 }
828 }
829 }
830
831 /* Update the symbol values of _edata and _end. */
832 for (n = new_file_h->e_shnum - 1; n; n--)
833 {
834 byte *symnames;
835 Elf32_Sym *symp, *symendp;
836
837 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
838 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
839 continue;
840
841 symnames = ((byte *) new_base
842 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
843 symp = (Elf32_Sym *) (NEW_SECTION_H (n).sh_offset + new_base);
844 symendp = (Elf32_Sym *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
845
846 for (; symp < symendp; symp ++)
847 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
848 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0)
849 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
850 }
851
852 /* This loop seeks out relocation sections for the data section, so
853 that it can undo relocations performed by the runtime linker. */
854 for (n = new_file_h->e_shnum - 1; n; n--)
855 {
856 Elf32_Shdr section = NEW_SECTION_H (n);
857 switch (section.sh_type) {
858 default:
859 break;
860 case SHT_REL:
861 case SHT_RELA:
862 /* This code handles two different size structs, but there should
863 be no harm in that provided that r_offset is always the first
864 member. */
865 nn = section.sh_info;
866 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
867 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
868 ".data1"))
869 {
870 Elf32_Addr offset = NEW_SECTION_H (nn).sh_addr -
871 NEW_SECTION_H (nn).sh_offset;
872 caddr_t reloc = old_base + section.sh_offset, end;
873 for (end = reloc + section.sh_size; reloc < end;
874 reloc += section.sh_entsize)
875 {
876 Elf32_Addr addr = ((Elf32_Rel *) reloc)->r_offset - offset;
877 memcpy (new_base + addr, old_base + addr, 4);
878 }
879 }
880 break;
881 }
882 }
883
884 #ifdef UNEXEC_USE_MAP_PRIVATE
885 if (lseek (new_file, 0, SEEK_SET) == -1)
886 fatal ("Can't rewind (%s): errno %d\n", new_name, errno);
887
888 if (write (new_file, new_base, new_file_size) != new_file_size)
889 fatal ("Can't write (%s): errno %d\n", new_name, errno);
890 #endif
891
892 /* Close the files and make the new file executable. */
893
894 if (close (old_file))
895 fatal ("Can't close (%s): errno %d\n", old_name, errno);
896
897 if (close (new_file))
898 fatal ("Can't close (%s): errno %d\n", new_name, errno);
899
900 if (stat (new_name, &stat_buf) == -1)
901 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
902
903 n = umask (777);
904 umask (n);
905 stat_buf.st_mode |= 0111 & ~n;
906 if (chmod (new_name, stat_buf.st_mode) == -1)
907 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
908 }