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e40c4104 RS |
1 | /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992 |
2 | Free Software Foundation, Inc. | |
d427b66a | 3 | |
e40c4104 RS |
4 | This program is free software; you can redistribute it and/or modify |
5 | it under the terms of the GNU General Public License as published by | |
6 | the Free Software Foundation; either version 2, or (at your option) | |
7 | any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | GNU General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
15 | along with this program; if not, write to the Free Software | |
16 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
d427b66a JB |
17 | |
18 | In other words, you are welcome to use, share and improve this program. | |
19 | You are forbidden to forbid anyone else to use, share and improve | |
20 | what you give them. Help stamp out software-hoarding! */ | |
21 | ||
22 | ||
23 | /* | |
24 | * unexec.c - Convert a running program into an a.out file. | |
25 | * | |
26 | * Author: Spencer W. Thomas | |
27 | * Computer Science Dept. | |
28 | * University of Utah | |
29 | * Date: Tue Mar 2 1982 | |
30 | * Modified heavily since then. | |
31 | * | |
32 | * Synopsis: | |
33 | * unexec (new_name, a_name, data_start, bss_start, entry_address) | |
34 | * char *new_name, *a_name; | |
35 | * unsigned data_start, bss_start, entry_address; | |
36 | * | |
37 | * Takes a snapshot of the program and makes an a.out format file in the | |
38 | * file named by the string argument new_name. | |
39 | * If a_name is non-NULL, the symbol table will be taken from the given file. | |
40 | * On some machines, an existing a_name file is required. | |
41 | * | |
42 | * The boundaries within the a.out file may be adjusted with the data_start | |
43 | * and bss_start arguments. Either or both may be given as 0 for defaults. | |
44 | * | |
45 | * Data_start gives the boundary between the text segment and the data | |
46 | * segment of the program. The text segment can contain shared, read-only | |
47 | * program code and literal data, while the data segment is always unshared | |
48 | * and unprotected. Data_start gives the lowest unprotected address. | |
49 | * The value you specify may be rounded down to a suitable boundary | |
50 | * as required by the machine you are using. | |
51 | * | |
52 | * Specifying zero for data_start means the boundary between text and data | |
53 | * should not be the same as when the program was loaded. | |
54 | * If NO_REMAP is defined, the argument data_start is ignored and the | |
55 | * segment boundaries are never changed. | |
56 | * | |
57 | * Bss_start indicates how much of the data segment is to be saved in the | |
58 | * a.out file and restored when the program is executed. It gives the lowest | |
59 | * unsaved address, and is rounded up to a page boundary. The default when 0 | |
60 | * is given assumes that the entire data segment is to be stored, including | |
61 | * the previous data and bss as well as any additional storage allocated with | |
62 | * break (2). | |
63 | * | |
64 | * The new file is set up to start at entry_address. | |
65 | * | |
66 | * If you make improvements I'd like to get them too. | |
67 | * harpo!utah-cs!thomas, thomas@Utah-20 | |
68 | * | |
69 | */ | |
70 | ||
71 | /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co. | |
72 | * ELF support added. | |
73 | * | |
74 | * Basic theory: the data space of the running process needs to be | |
75 | * dumped to the output file. Normally we would just enlarge the size | |
76 | * of .data, scooting everything down. But we can't do that in ELF, | |
77 | * because there is often something between the .data space and the | |
78 | * .bss space. | |
79 | * | |
80 | * In the temacs dump below, notice that the Global Offset Table | |
81 | * (.got) and the Dynamic link data (.dynamic) come between .data1 and | |
82 | * .bss. It does not work to overlap .data with these fields. | |
83 | * | |
84 | * The solution is to create a new .data segment. This segment is | |
85 | * filled with data from the current process. Since the contents of | |
86 | * various sections refer to sections by index, the new .data segment | |
87 | * is made the last in the table to avoid changing any existing index. | |
88 | ||
89 | * This is an example of how the section headers are changed. "Addr" | |
90 | * is a process virtual address. "Offset" is a file offset. | |
91 | ||
92 | raid:/nfs/raid/src/dist-18.56/src> dump -h temacs | |
93 | ||
94 | temacs: | |
95 | ||
96 | **** SECTION HEADER TABLE **** | |
97 | [No] Type Flags Addr Offset Size Name | |
98 | Link Info Adralgn Entsize | |
99 | ||
100 | [1] 1 2 0x80480d4 0xd4 0x13 .interp | |
101 | 0 0 0x1 0 | |
102 | ||
103 | [2] 5 2 0x80480e8 0xe8 0x388 .hash | |
104 | 3 0 0x4 0x4 | |
105 | ||
106 | [3] 11 2 0x8048470 0x470 0x7f0 .dynsym | |
107 | 4 1 0x4 0x10 | |
108 | ||
109 | [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr | |
110 | 0 0 0x1 0 | |
111 | ||
112 | [5] 9 2 0x8049010 0x1010 0x338 .rel.plt | |
113 | 3 7 0x4 0x8 | |
114 | ||
115 | [6] 1 6 0x8049348 0x1348 0x3 .init | |
116 | 0 0 0x4 0 | |
117 | ||
118 | [7] 1 6 0x804934c 0x134c 0x680 .plt | |
119 | 0 0 0x4 0x4 | |
120 | ||
121 | [8] 1 6 0x80499cc 0x19cc 0x3c56f .text | |
122 | 0 0 0x4 0 | |
123 | ||
124 | [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini | |
125 | 0 0 0x4 0 | |
126 | ||
127 | [10] 1 2 0x8085f40 0x3df40 0x69c .rodata | |
128 | 0 0 0x4 0 | |
129 | ||
130 | [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1 | |
131 | 0 0 0x4 0 | |
132 | ||
133 | [12] 1 3 0x8088330 0x3f330 0x20afc .data | |
134 | 0 0 0x4 0 | |
135 | ||
136 | [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1 | |
137 | 0 0 0x4 0 | |
138 | ||
139 | [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got | |
140 | 0 0 0x4 0x4 | |
141 | ||
142 | [15] 6 3 0x80a9874 0x60874 0x80 .dynamic | |
143 | 4 0 0x4 0x8 | |
144 | ||
145 | [16] 8 3 0x80a98f4 0x608f4 0x449c .bss | |
146 | 0 0 0x4 0 | |
147 | ||
148 | [17] 2 0 0 0x608f4 0x9b90 .symtab | |
149 | 18 371 0x4 0x10 | |
150 | ||
151 | [18] 3 0 0 0x6a484 0x8526 .strtab | |
152 | 0 0 0x1 0 | |
153 | ||
154 | [19] 3 0 0 0x729aa 0x93 .shstrtab | |
155 | 0 0 0x1 0 | |
156 | ||
157 | [20] 1 0 0 0x72a3d 0x68b7 .comment | |
158 | 0 0 0x1 0 | |
159 | ||
160 | raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs | |
161 | ||
162 | xemacs: | |
163 | ||
164 | **** SECTION HEADER TABLE **** | |
165 | [No] Type Flags Addr Offset Size Name | |
166 | Link Info Adralgn Entsize | |
167 | ||
168 | [1] 1 2 0x80480d4 0xd4 0x13 .interp | |
169 | 0 0 0x1 0 | |
170 | ||
171 | [2] 5 2 0x80480e8 0xe8 0x388 .hash | |
172 | 3 0 0x4 0x4 | |
173 | ||
174 | [3] 11 2 0x8048470 0x470 0x7f0 .dynsym | |
175 | 4 1 0x4 0x10 | |
176 | ||
177 | [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr | |
178 | 0 0 0x1 0 | |
179 | ||
180 | [5] 9 2 0x8049010 0x1010 0x338 .rel.plt | |
181 | 3 7 0x4 0x8 | |
182 | ||
183 | [6] 1 6 0x8049348 0x1348 0x3 .init | |
184 | 0 0 0x4 0 | |
185 | ||
186 | [7] 1 6 0x804934c 0x134c 0x680 .plt | |
187 | 0 0 0x4 0x4 | |
188 | ||
189 | [8] 1 6 0x80499cc 0x19cc 0x3c56f .text | |
190 | 0 0 0x4 0 | |
191 | ||
192 | [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini | |
193 | 0 0 0x4 0 | |
194 | ||
195 | [10] 1 2 0x8085f40 0x3df40 0x69c .rodata | |
196 | 0 0 0x4 0 | |
197 | ||
198 | [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1 | |
199 | 0 0 0x4 0 | |
200 | ||
201 | [12] 1 3 0x8088330 0x3f330 0x20afc .data | |
202 | 0 0 0x4 0 | |
203 | ||
204 | [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1 | |
205 | 0 0 0x4 0 | |
206 | ||
207 | [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got | |
208 | 0 0 0x4 0x4 | |
209 | ||
210 | [15] 6 3 0x80a9874 0x60874 0x80 .dynamic | |
211 | 4 0 0x4 0x8 | |
212 | ||
213 | [16] 8 3 0x80c6800 0x7d800 0 .bss | |
214 | 0 0 0x4 0 | |
215 | ||
216 | [17] 2 0 0 0x7d800 0x9b90 .symtab | |
217 | 18 371 0x4 0x10 | |
218 | ||
219 | [18] 3 0 0 0x87390 0x8526 .strtab | |
220 | 0 0 0x1 0 | |
221 | ||
222 | [19] 3 0 0 0x8f8b6 0x93 .shstrtab | |
223 | 0 0 0x1 0 | |
224 | ||
225 | [20] 1 0 0 0x8f949 0x68b7 .comment | |
226 | 0 0 0x1 0 | |
227 | ||
228 | [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data | |
229 | 0 0 0x4 0 | |
230 | ||
231 | * This is an example of how the file header is changed. "Shoff" is | |
232 | * the section header offset within the file. Since that table is | |
233 | * after the new .data section, it is moved. "Shnum" is the number of | |
234 | * sections, which we increment. | |
235 | * | |
236 | * "Phoff" is the file offset to the program header. "Phentsize" and | |
237 | * "Shentsz" are the program and section header entries sizes respectively. | |
238 | * These can be larger than the apparent struct sizes. | |
239 | ||
240 | raid:/nfs/raid/src/dist-18.56/src> dump -f temacs | |
241 | ||
242 | temacs: | |
243 | ||
244 | **** ELF HEADER **** | |
245 | Class Data Type Machine Version | |
246 | Entry Phoff Shoff Flags Ehsize | |
247 | Phentsize Phnum Shentsz Shnum Shstrndx | |
248 | ||
249 | 1 1 2 3 1 | |
250 | 0x80499cc 0x34 0x792f4 0 0x34 | |
251 | 0x20 5 0x28 21 19 | |
252 | ||
253 | raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs | |
254 | ||
255 | xemacs: | |
256 | ||
257 | **** ELF HEADER **** | |
258 | Class Data Type Machine Version | |
259 | Entry Phoff Shoff Flags Ehsize | |
260 | Phentsize Phnum Shentsz Shnum Shstrndx | |
261 | ||
262 | 1 1 2 3 1 | |
263 | 0x80499cc 0x34 0x96200 0 0x34 | |
264 | 0x20 5 0x28 22 19 | |
265 | ||
266 | * These are the program headers. "Offset" is the file offset to the | |
267 | * segment. "Vaddr" is the memory load address. "Filesz" is the | |
268 | * segment size as it appears in the file, and "Memsz" is the size in | |
269 | * memory. Below, the third segment is the code and the fourth is the | |
270 | * data: the difference between Filesz and Memsz is .bss | |
271 | ||
272 | raid:/nfs/raid/src/dist-18.56/src> dump -o temacs | |
273 | ||
274 | temacs: | |
275 | ***** PROGRAM EXECUTION HEADER ***** | |
276 | Type Offset Vaddr Paddr | |
277 | Filesz Memsz Flags Align | |
278 | ||
279 | 6 0x34 0x8048034 0 | |
280 | 0xa0 0xa0 5 0 | |
281 | ||
282 | 3 0xd4 0 0 | |
283 | 0x13 0 4 0 | |
284 | ||
285 | 1 0x34 0x8048034 0 | |
286 | 0x3f2f9 0x3f2f9 5 0x1000 | |
287 | ||
288 | 1 0x3f330 0x8088330 0 | |
289 | 0x215c4 0x25a60 7 0x1000 | |
290 | ||
291 | 2 0x60874 0x80a9874 0 | |
292 | 0x80 0 7 0 | |
293 | ||
294 | raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs | |
295 | ||
296 | xemacs: | |
297 | ***** PROGRAM EXECUTION HEADER ***** | |
298 | Type Offset Vaddr Paddr | |
299 | Filesz Memsz Flags Align | |
300 | ||
301 | 6 0x34 0x8048034 0 | |
302 | 0xa0 0xa0 5 0 | |
303 | ||
304 | 3 0xd4 0 0 | |
305 | 0x13 0 4 0 | |
306 | ||
307 | 1 0x34 0x8048034 0 | |
308 | 0x3f2f9 0x3f2f9 5 0x1000 | |
309 | ||
310 | 1 0x3f330 0x8088330 0 | |
311 | 0x3e4d0 0x3e4d0 7 0x1000 | |
312 | ||
313 | 2 0x60874 0x80a9874 0 | |
314 | 0x80 0 7 0 | |
315 | ||
316 | ||
317 | */ | |
e40c4104 RS |
318 | \f |
319 | /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc. | |
320 | * | |
321 | * The above mechanism does not work if the unexeced ELF file is being | |
322 | * re-layout by other applications (such as `strip'). All the applications | |
323 | * that re-layout the internal of ELF will layout all sections in ascending | |
324 | * order of their file offsets. After the re-layout, the data2 section will | |
325 | * still be the LAST section in the section header vector, but its file offset | |
326 | * is now being pushed far away down, and causes part of it not to be mapped | |
327 | * in (ie. not covered by the load segment entry in PHDR vector), therefore | |
328 | * causes the new binary to fail. | |
329 | * | |
330 | * The solution is to modify the unexec algorithm to insert the new data2 | |
331 | * section header right before the new bss section header, so their file | |
332 | * offsets will be in the ascending order. Since some of the section's (all | |
333 | * sections AFTER the bss section) indexes are now changed, we also need to | |
334 | * modify some fields to make them point to the right sections. This is done | |
335 | * by macro PATCH_INDEX. All the fields that need to be patched are: | |
336 | * | |
337 | * 1. ELF header e_shstrndx field. | |
338 | * 2. section header sh_link and sh_info field. | |
339 | * 3. symbol table entry st_shndx field. | |
340 | * | |
341 | * The above example now should look like: | |
342 | ||
343 | **** SECTION HEADER TABLE **** | |
344 | [No] Type Flags Addr Offset Size Name | |
345 | Link Info Adralgn Entsize | |
346 | ||
347 | [1] 1 2 0x80480d4 0xd4 0x13 .interp | |
348 | 0 0 0x1 0 | |
d427b66a | 349 | |
e40c4104 RS |
350 | [2] 5 2 0x80480e8 0xe8 0x388 .hash |
351 | 3 0 0x4 0x4 | |
352 | ||
353 | [3] 11 2 0x8048470 0x470 0x7f0 .dynsym | |
354 | 4 1 0x4 0x10 | |
355 | ||
356 | [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr | |
357 | 0 0 0x1 0 | |
358 | ||
359 | [5] 9 2 0x8049010 0x1010 0x338 .rel.plt | |
360 | 3 7 0x4 0x8 | |
361 | ||
362 | [6] 1 6 0x8049348 0x1348 0x3 .init | |
363 | 0 0 0x4 0 | |
364 | ||
365 | [7] 1 6 0x804934c 0x134c 0x680 .plt | |
366 | 0 0 0x4 0x4 | |
367 | ||
368 | [8] 1 6 0x80499cc 0x19cc 0x3c56f .text | |
369 | 0 0 0x4 0 | |
370 | ||
371 | [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini | |
372 | 0 0 0x4 0 | |
373 | ||
374 | [10] 1 2 0x8085f40 0x3df40 0x69c .rodata | |
375 | 0 0 0x4 0 | |
376 | ||
377 | [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1 | |
378 | 0 0 0x4 0 | |
379 | ||
380 | [12] 1 3 0x8088330 0x3f330 0x20afc .data | |
381 | 0 0 0x4 0 | |
382 | ||
383 | [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1 | |
384 | 0 0 0x4 0 | |
385 | ||
386 | [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got | |
387 | 0 0 0x4 0x4 | |
388 | ||
389 | [15] 6 3 0x80a9874 0x60874 0x80 .dynamic | |
390 | 4 0 0x4 0x8 | |
391 | ||
392 | [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data | |
393 | 0 0 0x4 0 | |
394 | ||
395 | [17] 8 3 0x80c6800 0x7d800 0 .bss | |
396 | 0 0 0x4 0 | |
397 | ||
398 | [18] 2 0 0 0x7d800 0x9b90 .symtab | |
399 | 19 371 0x4 0x10 | |
400 | ||
401 | [19] 3 0 0 0x87390 0x8526 .strtab | |
402 | 0 0 0x1 0 | |
403 | ||
404 | [20] 3 0 0 0x8f8b6 0x93 .shstrtab | |
405 | 0 0 0x1 0 | |
406 | ||
407 | [21] 1 0 0 0x8f949 0x68b7 .comment | |
408 | 0 0 0x1 0 | |
409 | ||
410 | */ | |
411 | \f | |
d427b66a JB |
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 | |
d7cb42c3 | 424 | #define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1) |
d427b66a | 425 | #else |
92b52293 | 426 | #include "config.h" |
d7cb42c3 | 427 | extern void fatal (char *, ...); |
d427b66a JB |
428 | #endif |
429 | ||
d8858cfe RS |
430 | #ifndef ELF_BSS_SECTION_NAME |
431 | #define ELF_BSS_SECTION_NAME ".bss" | |
432 | #endif | |
433 | ||
d427b66a JB |
434 | /* Get the address of a particular section or program header entry, |
435 | * accounting for the size of the entries. | |
436 | */ | |
437 | ||
438 | #define OLD_SECTION_H(n) \ | |
439 | (*(Elf32_Shdr *) ((byte *) old_section_h + old_file_h->e_shentsize * (n))) | |
440 | #define NEW_SECTION_H(n) \ | |
441 | (*(Elf32_Shdr *) ((byte *) new_section_h + new_file_h->e_shentsize * (n))) | |
442 | #define OLD_PROGRAM_H(n) \ | |
443 | (*(Elf32_Phdr *) ((byte *) old_program_h + old_file_h->e_phentsize * (n))) | |
444 | #define NEW_PROGRAM_H(n) \ | |
445 | (*(Elf32_Phdr *) ((byte *) new_program_h + new_file_h->e_phentsize * (n))) | |
446 | ||
e40c4104 RS |
447 | #define PATCH_INDEX(n) \ |
448 | do { \ | |
d7cb42c3 | 449 | if ((int) (n) >= old_bss_index) \ |
e40c4104 | 450 | (n)++; } while (0) |
d427b66a JB |
451 | typedef unsigned char byte; |
452 | ||
e40c4104 RS |
453 | /* Round X up to a multiple of Y. */ |
454 | ||
455 | int | |
456 | round_up (x, y) | |
457 | int x, y; | |
458 | { | |
459 | int rem = x % y; | |
460 | if (rem == 0) | |
461 | return x; | |
462 | return x - rem + y; | |
463 | } | |
464 | ||
d427b66a JB |
465 | /* **************************************************************** |
466 | * unexec | |
467 | * | |
468 | * driving logic. | |
469 | * | |
470 | * In ELF, this works by replacing the old .bss section with a new | |
471 | * .data section, and inserting an empty .bss immediately afterwards. | |
472 | * | |
473 | */ | |
474 | void | |
475 | unexec (new_name, old_name, data_start, bss_start, entry_address) | |
476 | char *new_name, *old_name; | |
477 | unsigned data_start, bss_start, entry_address; | |
478 | { | |
d427b66a JB |
479 | int new_file, old_file, new_file_size; |
480 | ||
481 | /* Pointers to the base of the image of the two files. */ | |
482 | caddr_t old_base, new_base; | |
483 | ||
484 | /* Pointers to the file, program and section headers for the old and new | |
485 | * files. | |
486 | */ | |
487 | Elf32_Ehdr *old_file_h, *new_file_h; | |
488 | Elf32_Phdr *old_program_h, *new_program_h; | |
489 | Elf32_Shdr *old_section_h, *new_section_h; | |
490 | ||
491 | /* Point to the section name table in the old file */ | |
492 | char *old_section_names; | |
493 | ||
494 | Elf32_Addr old_bss_addr, new_bss_addr; | |
495 | Elf32_Word old_bss_size, new_data2_size; | |
496 | Elf32_Off new_data2_offset; | |
497 | Elf32_Addr new_data2_addr; | |
498 | ||
e40c4104 | 499 | int n, nn, old_bss_index, old_data_index, new_data2_index; |
d427b66a JB |
500 | struct stat stat_buf; |
501 | ||
502 | /* Open the old file & map it into the address space. */ | |
503 | ||
504 | old_file = open (old_name, O_RDONLY); | |
505 | ||
506 | if (old_file < 0) | |
507 | fatal ("Can't open %s for reading: errno %d\n", old_name, errno); | |
508 | ||
509 | if (fstat (old_file, &stat_buf) == -1) | |
d7cb42c3 | 510 | fatal ("Can't fstat (%s): errno %d\n", old_name, errno); |
d427b66a JB |
511 | |
512 | old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0); | |
513 | ||
514 | if (old_base == (caddr_t) -1) | |
d7cb42c3 | 515 | fatal ("Can't mmap (%s): errno %d\n", old_name, errno); |
d427b66a JB |
516 | |
517 | #ifdef DEBUG | |
d7cb42c3 | 518 | fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size, |
d427b66a JB |
519 | old_base); |
520 | #endif | |
521 | ||
522 | /* Get pointers to headers & section names */ | |
523 | ||
524 | old_file_h = (Elf32_Ehdr *) old_base; | |
525 | old_program_h = (Elf32_Phdr *) ((byte *) old_base + old_file_h->e_phoff); | |
526 | old_section_h = (Elf32_Shdr *) ((byte *) old_base + old_file_h->e_shoff); | |
527 | old_section_names = (char *) old_base | |
d7cb42c3 | 528 | + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset; |
d427b66a JB |
529 | |
530 | /* Find the old .bss section. Figure out parameters of the new | |
531 | * data2 and bss sections. | |
532 | */ | |
533 | ||
d7cb42c3 RS |
534 | for (old_bss_index = 1; old_bss_index < (int) old_file_h->e_shnum; |
535 | old_bss_index++) | |
d427b66a JB |
536 | { |
537 | #ifdef DEBUG | |
538 | fprintf (stderr, "Looking for .bss - found %s\n", | |
d7cb42c3 | 539 | old_section_names + OLD_SECTION_H (old_bss_index).sh_name); |
d427b66a | 540 | #endif |
d7cb42c3 | 541 | if (!strcmp (old_section_names + OLD_SECTION_H (old_bss_index).sh_name, |
d8858cfe | 542 | ELF_BSS_SECTION_NAME)) |
d427b66a JB |
543 | break; |
544 | } | |
545 | if (old_bss_index == old_file_h->e_shnum) | |
546 | fatal ("Can't find .bss in %s.\n", old_name, 0); | |
547 | ||
d7cb42c3 RS |
548 | old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr; |
549 | old_bss_size = OLD_SECTION_H (old_bss_index).sh_size; | |
d427b66a | 550 | #if defined(emacs) || !defined(DEBUG) |
8bf761ce | 551 | new_bss_addr = (Elf32_Addr) sbrk (0); |
d427b66a JB |
552 | #else |
553 | new_bss_addr = old_bss_addr + old_bss_size + 0x1234; | |
554 | #endif | |
555 | new_data2_addr = old_bss_addr; | |
556 | new_data2_size = new_bss_addr - old_bss_addr; | |
d7cb42c3 | 557 | new_data2_offset = OLD_SECTION_H (old_bss_index).sh_offset; |
d427b66a JB |
558 | |
559 | #ifdef DEBUG | |
560 | fprintf (stderr, "old_bss_index %d\n", old_bss_index); | |
561 | fprintf (stderr, "old_bss_addr %x\n", old_bss_addr); | |
562 | fprintf (stderr, "old_bss_size %x\n", old_bss_size); | |
563 | fprintf (stderr, "new_bss_addr %x\n", new_bss_addr); | |
564 | fprintf (stderr, "new_data2_addr %x\n", new_data2_addr); | |
565 | fprintf (stderr, "new_data2_size %x\n", new_data2_size); | |
566 | fprintf (stderr, "new_data2_offset %x\n", new_data2_offset); | |
567 | #endif | |
568 | ||
569 | if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size) | |
570 | fatal (".bss shrank when undumping???\n", 0, 0); | |
571 | ||
d7cb42c3 | 572 | /* Set the output file to the right size and mmap it. Set |
d427b66a JB |
573 | * pointers to various interesting objects. stat_buf still has |
574 | * old_file data. | |
575 | */ | |
576 | ||
577 | new_file = open (new_name, O_RDWR | O_CREAT, 0666); | |
578 | if (new_file < 0) | |
d7cb42c3 | 579 | fatal ("Can't creat (%s): errno %d\n", new_name, errno); |
d427b66a JB |
580 | |
581 | new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size; | |
582 | ||
583 | if (ftruncate (new_file, new_file_size)) | |
d7cb42c3 | 584 | fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno); |
d427b66a | 585 | |
04f903c0 KH |
586 | #ifdef UNEXEC_USE_MAP_PRIVATE |
587 | new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, | |
588 | new_file, 0); | |
589 | #else | |
d427b66a JB |
590 | new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED, |
591 | new_file, 0); | |
04f903c0 | 592 | #endif |
d427b66a JB |
593 | |
594 | if (new_base == (caddr_t) -1) | |
d7cb42c3 | 595 | fatal ("Can't mmap (%s): errno %d\n", new_name, errno); |
d427b66a JB |
596 | |
597 | new_file_h = (Elf32_Ehdr *) new_base; | |
598 | new_program_h = (Elf32_Phdr *) ((byte *) new_base + old_file_h->e_phoff); | |
599 | new_section_h = (Elf32_Shdr *) | |
600 | ((byte *) new_base + old_file_h->e_shoff + new_data2_size); | |
601 | ||
602 | /* Make our new file, program and section headers as copies of the | |
603 | * originals. | |
604 | */ | |
605 | ||
606 | memcpy (new_file_h, old_file_h, old_file_h->e_ehsize); | |
607 | memcpy (new_program_h, old_program_h, | |
608 | old_file_h->e_phnum * old_file_h->e_phentsize); | |
e40c4104 RS |
609 | |
610 | /* Modify the e_shstrndx if necessary. */ | |
611 | PATCH_INDEX (new_file_h->e_shstrndx); | |
d427b66a JB |
612 | |
613 | /* Fix up file header. We'll add one section. Section header is | |
614 | * further away now. | |
615 | */ | |
616 | ||
617 | new_file_h->e_shoff += new_data2_size; | |
618 | new_file_h->e_shnum += 1; | |
619 | ||
620 | #ifdef DEBUG | |
621 | fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff); | |
622 | fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum); | |
623 | fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff); | |
624 | fprintf (stderr, "New section count %d\n", new_file_h->e_shnum); | |
625 | #endif | |
626 | ||
627 | /* Fix up a new program header. Extend the writable data segment so | |
628 | * that the bss area is covered too. Find that segment by looking | |
629 | * for a segment that ends just before the .bss area. Make sure | |
630 | * that no segments are above the new .data2. Put a loop at the end | |
631 | * to adjust the offset and address of any segment that is above | |
632 | * data2, just in case we decide to allow this later. | |
633 | */ | |
634 | ||
635 | for (n = new_file_h->e_phnum - 1; n >= 0; n--) | |
636 | { | |
e40c4104 RS |
637 | /* Compute maximum of all requirements for alignment of section. */ |
638 | int alignment = (NEW_PROGRAM_H (n)).p_align; | |
639 | if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment) | |
640 | alignment = OLD_SECTION_H (old_bss_index).sh_addralign; | |
641 | ||
d7cb42c3 | 642 | if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr) |
d427b66a JB |
643 | fatal ("Program segment above .bss in %s\n", old_name, 0); |
644 | ||
d7cb42c3 | 645 | if (NEW_PROGRAM_H (n).p_type == PT_LOAD |
e40c4104 RS |
646 | && (round_up ((NEW_PROGRAM_H (n)).p_vaddr |
647 | + (NEW_PROGRAM_H (n)).p_filesz, | |
648 | alignment) | |
649 | == round_up (old_bss_addr, alignment))) | |
d427b66a JB |
650 | break; |
651 | } | |
652 | if (n < 0) | |
653 | fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0); | |
654 | ||
d7cb42c3 RS |
655 | NEW_PROGRAM_H (n).p_filesz += new_data2_size; |
656 | NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz; | |
d427b66a JB |
657 | |
658 | #if 0 /* Maybe allow section after data2 - does this ever happen? */ | |
659 | for (n = new_file_h->e_phnum - 1; n >= 0; n--) | |
660 | { | |
d7cb42c3 RS |
661 | if (NEW_PROGRAM_H (n).p_vaddr |
662 | && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr) | |
663 | NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size; | |
d427b66a | 664 | |
d7cb42c3 RS |
665 | if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset) |
666 | NEW_PROGRAM_H (n).p_offset += new_data2_size; | |
d427b66a JB |
667 | } |
668 | #endif | |
669 | ||
670 | /* Fix up section headers based on new .data2 section. Any section | |
671 | * whose offset or virtual address is after the new .data2 section | |
672 | * gets its value adjusted. .bss size becomes zero and new address | |
673 | * is set. data2 section header gets added by copying the existing | |
674 | * .data header and modifying the offset, address and size. | |
675 | */ | |
d7cb42c3 | 676 | for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum; |
d427b66a | 677 | old_data_index++) |
d7cb42c3 | 678 | if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name, |
d427b66a JB |
679 | ".data")) |
680 | break; | |
681 | if (old_data_index == old_file_h->e_shnum) | |
682 | fatal ("Can't find .data in %s.\n", old_name, 0); | |
683 | ||
e40c4104 RS |
684 | /* Walk through all section headers, insert the new data2 section right |
685 | before the new bss section. */ | |
d7cb42c3 | 686 | for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++) |
d427b66a JB |
687 | { |
688 | caddr_t src; | |
e40c4104 RS |
689 | /* If it is bss section, insert the new data2 section before it. */ |
690 | if (n == old_bss_index) | |
691 | { | |
692 | /* Steal the data section header for this data2 section. */ | |
d7cb42c3 | 693 | memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index), |
e40c4104 RS |
694 | new_file_h->e_shentsize); |
695 | ||
d7cb42c3 RS |
696 | NEW_SECTION_H (nn).sh_addr = new_data2_addr; |
697 | NEW_SECTION_H (nn).sh_offset = new_data2_offset; | |
698 | NEW_SECTION_H (nn).sh_size = new_data2_size; | |
e40c4104 RS |
699 | /* Use the bss section's alignment. This will assure that the |
700 | new data2 section always be placed in the same spot as the old | |
701 | bss section by any other application. */ | |
d7cb42c3 | 702 | NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign; |
e40c4104 RS |
703 | |
704 | /* Now copy over what we have in the memory now. */ | |
d7cb42c3 RS |
705 | memcpy (NEW_SECTION_H (nn).sh_offset + new_base, |
706 | (caddr_t) OLD_SECTION_H (n).sh_addr, | |
e40c4104 RS |
707 | new_data2_size); |
708 | nn++; | |
709 | } | |
710 | ||
d7cb42c3 | 711 | memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n), |
e40c4104 RS |
712 | old_file_h->e_shentsize); |
713 | ||
714 | /* The new bss section's size is zero, and its file offset and virtual | |
715 | address should be off by NEW_DATA2_SIZE. */ | |
716 | if (n == old_bss_index) | |
717 | { | |
718 | /* NN should be `old_bss_index + 1' at this point. */ | |
d7cb42c3 RS |
719 | NEW_SECTION_H (nn).sh_offset += new_data2_size; |
720 | NEW_SECTION_H (nn).sh_addr += new_data2_size; | |
e40c4104 RS |
721 | /* Let the new bss section address alignment be the same as the |
722 | section address alignment followed the old bss section, so | |
723 | this section will be placed in exactly the same place. */ | |
d7cb42c3 RS |
724 | NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign; |
725 | NEW_SECTION_H (nn).sh_size = 0; | |
e40c4104 | 726 | } |
85b2e0ee RS |
727 | else |
728 | { | |
729 | /* Any section that was original placed AFTER the bss | |
730 | section should now be off by NEW_DATA2_SIZE. */ | |
731 | if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset) | |
732 | NEW_SECTION_H (nn).sh_offset += new_data2_size; | |
733 | /* Any section that was originally placed after the section | |
734 | header table should now be off by the size of one section | |
735 | header table entry. */ | |
736 | if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff) | |
737 | NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize; | |
738 | } | |
739 | ||
e40c4104 RS |
740 | /* If any section hdr refers to the section after the new .data |
741 | section, make it refer to next one because we have inserted | |
8917361f | 742 | a new section in between. */ |
e40c4104 | 743 | |
d7cb42c3 | 744 | PATCH_INDEX (NEW_SECTION_H (nn).sh_link); |
8917361f RS |
745 | /* For symbol tables, info is a symbol table index, |
746 | so don't change it. */ | |
747 | if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB | |
748 | && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM) | |
749 | PATCH_INDEX (NEW_SECTION_H (nn).sh_info); | |
750 | ||
751 | /* Now, start to copy the content of sections. */ | |
d7cb42c3 RS |
752 | if (NEW_SECTION_H (nn).sh_type == SHT_NULL |
753 | || NEW_SECTION_H (nn).sh_type == SHT_NOBITS) | |
d427b66a | 754 | continue; |
e40c4104 RS |
755 | |
756 | /* Write out the sections. .data and .data1 (and data2, called | |
8917361f RS |
757 | ".data" in the strings table) get copied from the current process |
758 | instead of the old file. */ | |
d7cb42c3 RS |
759 | if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data") |
760 | || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name), | |
d427b66a | 761 | ".data1")) |
d7cb42c3 | 762 | src = (caddr_t) OLD_SECTION_H (n).sh_addr; |
d427b66a | 763 | else |
d7cb42c3 | 764 | src = old_base + OLD_SECTION_H (n).sh_offset; |
e40c4104 | 765 | |
d7cb42c3 RS |
766 | memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src, |
767 | NEW_SECTION_H (nn).sh_size); | |
e40c4104 | 768 | |
8917361f | 769 | /* If it is the symbol table, its st_shndx field needs to be patched. */ |
d7cb42c3 RS |
770 | if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB |
771 | || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM) | |
e40c4104 | 772 | { |
d7cb42c3 | 773 | Elf32_Shdr *spt = &NEW_SECTION_H (nn); |
e40c4104 | 774 | unsigned int num = spt->sh_size / spt->sh_entsize; |
d7cb42c3 | 775 | Elf32_Sym * sym = (Elf32_Sym *) (NEW_SECTION_H (nn).sh_offset + |
e40c4104 RS |
776 | new_base); |
777 | for (; num--; sym++) | |
778 | { | |
779 | if ((sym->st_shndx == SHN_UNDEF) | |
780 | || (sym->st_shndx == SHN_ABS) | |
781 | || (sym->st_shndx == SHN_COMMON)) | |
782 | continue; | |
783 | ||
d7cb42c3 | 784 | PATCH_INDEX (sym->st_shndx); |
e40c4104 RS |
785 | } |
786 | } | |
d427b66a JB |
787 | } |
788 | ||
8917361f | 789 | /* Update the symbol values of _edata and _end. */ |
8bf761ce RS |
790 | for (n = new_file_h->e_shnum - 1; n; n--) |
791 | { | |
792 | byte *symnames; | |
793 | Elf32_Sym *symp, *symendp; | |
794 | ||
795 | if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM | |
796 | && NEW_SECTION_H (n).sh_type != SHT_SYMTAB) | |
797 | continue; | |
798 | ||
8c1e9afe KH |
799 | symnames = ((byte *) new_base |
800 | + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset); | |
8bf761ce RS |
801 | symp = (Elf32_Sym *) (NEW_SECTION_H (n).sh_offset + new_base); |
802 | symendp = (Elf32_Sym *) ((byte *)symp + NEW_SECTION_H (n).sh_size); | |
803 | ||
804 | for (; symp < symendp; symp ++) | |
805 | if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0 | |
806 | || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0) | |
807 | memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr)); | |
808 | } | |
809 | ||
48240339 KH |
810 | #ifdef SOLARIS2 |
811 | /* This loop seeks out relocation sections for the data section, so | |
812 | that it can undo relocations performed by the runtime linker. */ | |
813 | for (n = new_file_h->e_shnum - 1; n; n--) | |
814 | { | |
815 | Elf32_Shdr section = NEW_SECTION_H (n); | |
816 | switch (section.sh_type) { | |
817 | default: | |
818 | break; | |
819 | case SHT_REL: | |
820 | case SHT_RELA: | |
821 | /* This code handles two different size structs, but there | |
822 | should be no harm in that provided that r_offset is always | |
823 | the first member. */ | |
824 | nn = section.sh_info; | |
825 | if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data") | |
826 | || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name), | |
827 | ".data1")) | |
828 | { | |
829 | Elf32_Addr offset = NEW_SECTION_H (nn).sh_addr - | |
830 | NEW_SECTION_H (nn).sh_offset; | |
831 | caddr_t reloc = old_base + section.sh_offset, end; | |
832 | for (end = reloc + section.sh_size; reloc < end; | |
833 | reloc += section.sh_entsize) | |
834 | { | |
835 | Elf32_Addr addr = ((Elf32_Rel *) reloc)->r_offset - offset; | |
836 | memcpy (new_base + addr, old_base + addr, 4); | |
837 | } | |
838 | } | |
839 | break; | |
840 | } | |
841 | } | |
842 | #endif | |
843 | ||
04f903c0 KH |
844 | #ifdef UNEXEC_USE_MAP_PRIVATE |
845 | if (lseek (new_file, 0, SEEK_SET) == -1) | |
846 | fatal ("Can't rewind (%s): errno %d\n", new_name, errno); | |
847 | ||
848 | if (write (new_file, new_base, new_file_size) != new_file_size) | |
849 | fatal ("Can't write (%s): errno %d\n", new_name, errno); | |
850 | #endif | |
851 | ||
8917361f | 852 | /* Close the files and make the new file executable. */ |
d427b66a JB |
853 | |
854 | if (close (old_file)) | |
d7cb42c3 | 855 | fatal ("Can't close (%s): errno %d\n", old_name, errno); |
d427b66a JB |
856 | |
857 | if (close (new_file)) | |
d7cb42c3 | 858 | fatal ("Can't close (%s): errno %d\n", new_name, errno); |
d427b66a JB |
859 | |
860 | if (stat (new_name, &stat_buf) == -1) | |
d7cb42c3 | 861 | fatal ("Can't stat (%s): errno %d\n", new_name, errno); |
d427b66a JB |
862 | |
863 | n = umask (777); | |
864 | umask (n); | |
865 | stat_buf.st_mode |= 0111 & ~n; | |
866 | if (chmod (new_name, stat_buf.st_mode) == -1) | |
d7cb42c3 | 867 | fatal ("Can't chmod (%s): errno %d\n", new_name, errno); |
d427b66a | 868 | } |