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comparison dynodump/dynodump.c @ 153:25f70ba0133c r20-3b3

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date Mon, 13 Aug 2007 09:38:25 +0200
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152:4c132ee2d62b 153:25f70ba0133c
1 /*
2 * Copyright (c) 1995 by Sun Microsystems, Inc.
3 * All rights reserved.
4 *
5 * This source code is a product of Sun Microsystems, Inc. and is provided
6 * for unrestricted use provided that this legend is included on all tape
7 * media and as a part of the software program in whole or part. Users
8 * may copy or modify this source code without charge, but are not authorized
9 * to license or distribute it to anyone else except as part of a product or
10 * program developed by the user.
11 *
12 * THIS PROGRAM CONTAINS SOURCE CODE COPYRIGHTED BY SUN MICROSYSTEMS, INC.
13 * SUN MICROSYSTEMS, INC., MAKES NO REPRESENTATIONS ABOUT THE SUITABLITY
14 * OF SUCH SOURCE CODE FOR ANY PURPOSE. IT IS PROVIDED "AS IS" WITHOUT
15 * EXPRESS OR IMPLIED WARRANTY OF ANY KIND. SUN MICROSYSTEMS, INC. DISCLAIMS
16 * ALL WARRANTIES WITH REGARD TO SUCH SOURCE CODE, INCLUDING ALL IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN
18 * NO EVENT SHALL SUN MICROSYSTEMS, INC. BE LIABLE FOR ANY SPECIAL, INDIRECT,
19 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
20 * FROM USE OF SUCH SOURCE CODE, REGARDLESS OF THE THEORY OF LIABILITY.
21 *
22 * This source code is provided with no support and without any obligation on
23 * the part of Sun Microsystems, Inc. to assist in its use, correction,
24 * modification or enhancement.
25 *
26 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
27 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS
28 * SOURCE CODE OR ANY PART THEREOF.
29 *
30 * Sun Microsystems, Inc.
31 * 2550 Garcia Avenue
32 * Mountain View, California 94043
33 */
34
35 /*
36 * dynodump(3x) dumps a running executable into a specified ELF file. The new
37 * file consists of the memory contents of the original file together with any
38 * heap. This heap is assigned to a new `.heap' section within the new file.
39 *
40 * The new file may be re-executed, and will contain any data modifications
41 * made to the original image up until the time dynodump(3x) was called.
42 *
43 * The original image may have undergone relocations (performed by ld.so.1)
44 * prior to control being transferred to the image. These relocations will
45 * reside as the data copied from the image. To prevent subsequent executions
46 * of the new image from undergoing the same relocations, any relocation entries
47 * (besides copy or jump slot relocations) are nulled out. Note that copy
48 * relocations such as required for __iob must be reinitialized each time the
49 * process starts, so it is not sufficient to simply null out the .dynamic
50 * sections relocation information. The effect of this is that if the new
51 * image was bound to definitions in any shared object dependencies, then these
52 * dependencies *must* reside in the same location as when dynodump(3x) was
53 * called. Any changes to the shared object dependencies of the new image, or
54 * uses of such things as LD_PRELOAD, may result in the bindings encoded in the
55 * image becoming invalid.
56 *
57 * The following flags modify the data of the image created:
58 *
59 * RTLD_SAVREL save the original relocation data. Under this option any
60 * relocation offset is reset to contain the same data as was
61 * found in the images original file.
62 *
63 * This option allows relocation information to be retained in the
64 * new image so that it may be re-executed when the new image is
65 * run. This allows far greater flexibility as the new image can
66 * now take advantage of new shared objects.
67 *
68 * Note. under this mechanism, any data item that undergoes
69 * relocation and is then further modified during the execution of
70 * the image before dynodump(3x) is called will lose the
71 * modification that occured during the applications execution.
72 *
73 * N.B. The above commentary is not quite correct in the flags have been hardwired
74 * to RTLD_SAVREL.
75 */
76 #pragma ident "@(#) $Id: dynodump.c,v 1.3 1997/05/29 04:22:30 steve Exp $ - SMI"
77
78 #include <sys/param.h>
79 #include <sys/procfs.h>
80 #include <fcntl.h>
81 #include <stdio.h>
82 #include <libelf.h>
83 #include <link.h>
84 #include <stdlib.h>
85 #include <string.h>
86 #include <unistd.h>
87 #include <errno.h>
88 #include <malloc.h>
89 #include "machdep.h"
90 #include "_dynodump.h"
91
92 /*
93 * Generic elf error message generator
94 */
95 static int
96 elferr(const char * str)
97 {
98 fprintf(stderr, "%s: %s\n", str, elf_errmsg(elf_errno()));
99 return (1);
100 }
101
102 int dynodump (const char * file);
103 int
104 dynodump(const char * file)
105 {
106 Elf *ielf, *oelf;
107 Ehdr *iehdr, *oehdr;
108 Phdr *iphdr, *ophdr, *data_phdr = 0;
109 Cache *icache, *ocache, *_icache, *_ocache;
110 Cache *data_cache = 0, *shstr_cache = 0;
111 Cache *heap_cache = 0;
112 Word heap_sz = 0;
113 Elf_Scn *scn;
114 Shdr *shdr;
115 Elf_Data *data, rundata;
116 Half ndx, _ndx;
117 int fd, _fd;
118 Addr edata, _addr;
119 char *istrs, *ostrs, *_ostrs, proc[16];
120 const char heap[] = ".heap";
121 prstatus_t pstat;
122
123 /* make a call to the processor specific un-init stuff */
124 dynodump_uninit();
125
126 /*
127 * Obtain a file descriptor for this process,
128 * for the executable and get a prstatus_t
129 * structure.
130 */
131 sprintf(proc, "/proc/%ld", getpid());
132 if (((_fd = open(proc, O_RDONLY, 0)) == -1) ||
133 ((fd = ioctl(_fd, PIOCOPENM, (void *)0)) == -1) ||
134 (ioctl(_fd, PIOCSTATUS, &pstat) == -1)) {
135 fprintf(stderr, "/proc: initialization error: %s\n",
136 strerror(errno));
137 close(_fd);
138 return (1);
139 }
140 close(_fd);
141
142 /*
143 * Initialize with the ELF library and make sure this is an executable
144 * ELF file we're dealing with.
145 */
146 elf_version(EV_CURRENT);
147 if ((ielf = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
148 close(fd);
149 return (elferr("elf_begin"));
150 }
151 close(fd);
152
153 if ((elf_kind(ielf) != ELF_K_ELF) ||
154 ((iehdr = elf_getehdr(ielf)) == NULL) ||
155 (iehdr->e_type != ET_EXEC)) {
156 fprintf(stderr, "image is not an ELF executable\n");
157 elf_end(ielf);
158 return (1);
159 }
160 /*
161 * Elf_elf_header(iehdr);
162 */
163
164 /*
165 * Create the new output file.
166 */
167 if ((fd = open(file, O_RDWR | O_CREAT | O_TRUNC, 0777)) == -1) {
168 fprintf(stderr, "%s: open failed: %s\n", file,
169 strerror(errno));
170 elf_end(ielf);
171 return (1);
172 }
173 if ((oelf = elf_begin(fd, ELF_C_WRITE, NULL)) == NULL) {
174 elf_end(ielf);
175 close(fd);
176 return (elferr("elf_begin"));
177 }
178
179 /*
180 * Obtain the input program headers. Remember the data segments
181 * program header entry as this will be updated later to reflect the
182 * new .heap sections size.
183 */
184 if ((iphdr = elf_getphdr(ielf)) == NULL)
185 return (elferr("elf_getphdr"));
186
187 for (ndx = 0, ophdr = iphdr; ndx != iehdr->e_phnum; ndx++, ophdr++) {
188 /*
189 * Save the program header that contains the NOBITS section, or
190 * the last loadable program header if no NOBITS exists.
191 * A NOBITS section translates to a memory size requirement that
192 * is greater than the file data it is mapped from.
193 */
194 if (ophdr->p_type == PT_LOAD) {
195 if (ophdr->p_filesz != ophdr->p_memsz)
196 data_phdr = ophdr;
197 else if (data_phdr) {
198 if (data_phdr->p_vaddr < ophdr->p_vaddr)
199 data_phdr = ophdr;
200 } else
201 data_phdr = ophdr;
202 }
203 }
204 if (data_phdr == 0) {
205 fprintf(stderr, "no data segment found!\n");
206 return (0);
207 }
208
209 /*
210 * Obtain the input files section header string table.
211 */
212 if ((scn = elf_getscn(ielf, iehdr->e_shstrndx)) == NULL)
213 return (elferr("elf_getscn"));
214 if ((data = elf_getdata(scn, NULL)) == NULL)
215 return (elferr("elf_getdata"));
216 istrs = data->d_buf;
217
218 /*
219 * Construct a cache to maintain the input files section information.
220 */
221 if ((icache = (Cache *) malloc(iehdr->e_shnum * sizeof (Cache))) == 0) {
222 fprintf(stderr, "malloc failed: %s\n", strerror(errno));
223 return (1);
224 }
225 _icache = icache;
226 _icache++;
227
228 /*
229 * Traverse each section from the input file.
230 */
231 for (ndx = 1, scn = 0;
232 (_icache->c_scn = elf_nextscn(ielf, scn));
233 ndx++, scn = _icache->c_scn, _icache++) {
234
235 if ((_icache->c_shdr = shdr = elf_getshdr(_icache->c_scn)) == NULL)
236 return (elferr("elf_getshdr"));
237
238 if ((_icache->c_data = elf_getdata(_icache->c_scn, NULL)) == NULL)
239 return (elferr("elf_getdata"));
240
241 _icache->c_name = istrs + (size_t)(shdr->sh_name);
242
243 /*
244 * For each section that has a virtual address reestablish the
245 * data buffer to point to the memory image.
246 *
247 * if (shdr->sh_addr)
248 * _icache->c_data->d_buf = (void *)shdr->sh_addr;
249 */
250
251 /*
252 * Remember the last section of the data segment, the new .heap
253 * section will be added after this section.
254 * If we already have one, then set data_cache to the previous
255 * section and set heap_cache to this one.
256 */
257 if ((shdr->sh_addr + shdr->sh_size)
258 == (data_phdr->p_vaddr + data_phdr->p_memsz)) {
259 if (strcmp(_icache->c_name, heap) == 0) {
260 #ifdef DEBUG
261 printf("Found a previous .heap section\n");
262 #endif
263 data_cache = _icache - 1;
264 heap_cache = _icache;
265 heap_sz = shdr->sh_size;
266 } else {
267 data_cache = _icache;
268 }
269 }
270
271 /*
272 * Remember the section header string table as this will be
273 * rewritten with the new .heap name.
274 */
275 if ((shdr->sh_type == SHT_STRTAB) &&
276 ((strcmp(_icache->c_name, ".shstrtab")) == 0))
277 shstr_cache = _icache;
278 }
279 if (data_cache == 0) {
280 fprintf(stderr, "final data section not found!\n");
281 return (0);
282 }
283
284 /*
285 * Determine the new .heap section to create.
286 */
287 rundata.d_buf = (void *)(data_cache->c_shdr->sh_addr +
288 data_cache->c_shdr->sh_size);
289 rundata.d_size = (int)sbrk(0) - (int)rundata.d_buf;
290 rundata.d_type = ELF_T_BYTE;
291 rundata.d_off = 0;
292 rundata.d_align = 1;
293 rundata.d_version = EV_CURRENT;
294
295 /*
296 * From the new data buffer determine the new value for _end and _edata.
297 * This will also be used to update the data segment program header.
298 *
299 * If we had a .heap section, then its size is part of the program
300 * headers notion of data size. Because we're only going to output one
301 * heap section (ignoring the one in the running binary) we need to
302 * subract the size of that which we're ignoring.
303 */
304 if (heap_cache) {
305 edata = S_ROUND((data_phdr->p_vaddr
306 + data_phdr->p_memsz
307 - heap_sz), rundata.d_align) + rundata.d_size;
308 } else {
309 edata = S_ROUND((data_phdr->p_vaddr + data_phdr->p_memsz),
310 rundata.d_align) + rundata.d_size;
311 }
312
313 /*
314 * We're now ready to construct the new elf image.
315 *
316 * Obtain a new elf header and initialize it with any basic information
317 * that isn't calculated as part of elf_update(). Bump the section
318 * header string table index to account for the .heap section we'll be
319 * adding.
320 */
321 if ((oehdr = elf_newehdr(oelf)) == NULL)
322 return (elferr("elf_newehdr"));
323
324 oehdr->e_entry = iehdr->e_entry;
325 oehdr->e_machine = iehdr->e_machine;
326 oehdr->e_type = iehdr->e_type;
327 oehdr->e_flags = iehdr->e_flags;
328 /*
329 * If we already have a heap section, we don't need any adjustment
330 */
331 if (heap_cache)
332 oehdr->e_shstrndx = iehdr->e_shstrndx;
333 else
334 oehdr->e_shstrndx = iehdr->e_shstrndx + 1;
335
336 #ifdef DEBUG
337 printf("iehdr->e_flags = %x\n", iehdr->e_flags);
338 printf("iehdr->e_entry = %x\n", iehdr->e_entry);
339 printf("iehdr->e_shstrndx= %d\n", iehdr->e_shstrndx);
340 printf("iehdr->e_machine = %d\n", iehdr->e_machine);
341 printf("iehdr->e_type = 0x%x\n", iehdr->e_type);
342 printf("oehdr->e_machine = %d\n", oehdr->e_machine);
343 printf("oehdr->e_type = 0x%x\n", oehdr->e_type);
344 #endif
345
346 /*
347 * Obtain a new set of program headers. Initialize these with the same
348 * information as the input program headers and update the data segment
349 * to reflect the new .heap section.
350 */
351 if ((ophdr = elf_newphdr(oelf, iehdr->e_phnum)) == NULL)
352 return (elferr("elf_newphdr"));
353
354 for (ndx = 0; ndx != iehdr->e_phnum; ndx++, iphdr++, ophdr++) {
355 *ophdr = *iphdr;
356 if (data_phdr == iphdr)
357 ophdr->p_filesz = ophdr->p_memsz = edata - ophdr->p_vaddr;
358 }
359
360 /*
361 * Obtain a new set of sections.
362 */
363 _icache = icache;
364 _icache++;
365 for (ndx = 1; ndx != iehdr->e_shnum; ndx++, _icache++) {
366 /*
367 * Skip the heap section of the running executable
368 */
369 if (_icache == heap_cache)
370 continue;
371 /*
372 * Create a matching section header in the output file.
373 */
374 if ((scn = elf_newscn(oelf)) == NULL)
375 return (elferr("elf_newscn"));
376 if ((shdr = elf_getshdr(scn)) == NULL)
377 return (elferr("elf_getshdr"));
378 *shdr = *_icache->c_shdr;
379
380 /*
381 * Create a matching data buffer for this section.
382 */
383 if ((data = elf_newdata(scn)) == NULL)
384 return (elferr("elf_newdata"));
385 *data = *_icache->c_data;
386
387 /*
388 * For each section that has a virtual address reestablish the
389 * data buffer to point to the memory image. Note, we skip
390 * the plt section.
391 */
392 if ((shdr->sh_addr) && (!((shdr->sh_type == SHT_PROGBITS)
393 && (strcmp(_icache->c_name, ".plt") == 0))))
394 data->d_buf = (void *)shdr->sh_addr;
395
396 /*
397 * Update any NOBITS section to indicate that it now contains
398 * data.
399 */
400 if (shdr->sh_type == SHT_NOBITS)
401 shdr->sh_type = SHT_PROGBITS;
402
403 /*
404 * Add the new .heap section after the last section of the
405 * present data segment. If we had a heap section, then
406 * this is the section preceding it.
407 */
408 if (data_cache == _icache) {
409 if ((scn = elf_newscn(oelf)) == NULL)
410 return (elferr("elf_newscn"));
411 if ((shdr = elf_getshdr(scn)) == NULL)
412 return (elferr("elf_getshdr"));
413 shdr->sh_type = SHT_PROGBITS;
414 shdr->sh_flags = SHF_ALLOC | SHF_WRITE;
415
416 if ((data = elf_newdata(scn)) == NULL)
417 return (elferr("elf_newdata"));
418 *data = rundata;
419 }
420
421 /*
422 * Update the section header string table size to reflect the
423 * new section name (only if we didn't already have a heap).
424 */
425 if (!heap_cache) {
426 if (shstr_cache && (shstr_cache == _icache)) {
427 data->d_size += sizeof (heap);
428 }
429 }
430 }
431
432 /*
433 * Write out the new image, and obtain a new elf descriptor that will
434 * allow us to write to the new image.
435 */
436 if (elf_update(oelf, ELF_C_WRITE) == -1)
437 return (elferr("elf_update"));
438 elf_end(oelf);
439 if ((oelf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL)
440 return (elferr("elf_begin"));
441 if ((oehdr = elf_getehdr(oelf)) == NULL)
442 return (elferr("elf_getehdr"));
443
444 /*
445 * Obtain the output files section header string table.
446 */
447 if ((scn = elf_getscn(oelf, oehdr->e_shstrndx)) == NULL)
448 return (elferr("elf_getscn"));
449 if ((data = elf_getdata(scn, NULL)) == NULL)
450 return (elferr("elf_getdata"));
451 ostrs = _ostrs = data->d_buf;
452 *_ostrs++ = '\0';
453
454 /*
455 * Construct a cache to maintain the output files section information.
456 */
457 if ((ocache = (Cache *)malloc(oehdr->e_shnum * sizeof (Cache))) == 0) {
458 fprintf(stderr, "malloc failed: %s\n", strerror(errno));
459 return (1);
460 }
461 _ocache = ocache;
462 _ocache++;
463 _icache = icache;
464 _icache++;
465
466 /*
467 * Traverse each section from the input file rebuilding the section
468 * header string table as we go.
469 */
470 _ndx = _addr = 0;
471 for (ndx = 1, scn = 0;
472 (_ocache->c_scn = elf_nextscn(oelf, scn));
473 ndx++, scn = _ocache->c_scn, _ocache++, _icache++) {
474
475 const char *strs;
476
477 if (_icache == heap_cache) {
478 #ifdef DEBUG
479 printf("ignoring .heap section in input\n");
480 #endif
481 _icache++;
482 }
483
484 if ((_ocache->c_shdr = shdr =
485 elf_getshdr(_ocache->c_scn)) == NULL)
486 return (elferr("elf_getshdr"));
487 if ((_ocache->c_data =
488 elf_getdata(_ocache->c_scn, NULL)) == NULL)
489 return (elferr("elf_getdata"));
490
491 /*
492 * If were inserting the new .heap section, insert the new
493 * section name and initialize it's virtual address.
494 */
495 if (_addr) {
496 strs = heap;
497 shdr->sh_addr = S_ROUND(_addr, shdr->sh_addralign);
498 _addr = 0;
499 } else {
500 strs = istrs + (size_t)(_icache->c_shdr->sh_name);
501 }
502
503 strcpy(_ostrs, strs);
504 shdr->sh_name = _ostrs - ostrs;
505 _ocache->c_name = _ostrs;
506 _ostrs += strlen(strs) + 1;
507
508 /*
509 * If we've inserted a new section any later section may need
510 * their sh_link fields updated.
511 * If we already had a heap section, then this is not required.
512 */
513 if (!heap_cache) {
514 if (_ndx) {
515 if (_ocache->c_shdr->sh_link >= _ndx)
516 _ocache->c_shdr->sh_link++;
517 }
518 }
519
520 /*
521 * If this is the last section of the original data segment
522 * determine sufficient information to initialize the new .heap
523 * section which will be obtained next.
524 */
525 if (data_cache == _icache) {
526 _ndx = ndx + 1;
527 _addr = shdr->sh_addr + shdr->sh_size;
528 _icache--;
529 data_cache = 0;
530 }
531 }
532
533 /*
534 * Now that we have a complete description of the new image update any
535 * sections that are required.
536 *
537 * o update the value of _edata and _end.
538 *
539 * o reset any relocation entries if necessary.
540 */
541 _ocache = &ocache[1];
542 _icache = &icache[1];
543 for (ndx = 1; ndx < oehdr->e_shnum; ndx++, _ocache++, _icache++) {
544 if ((_ocache->c_shdr->sh_type == SHT_SYMTAB) ||
545 (_ocache->c_shdr->sh_type == SHT_DYNSYM))
546 update_sym(ocache, _ocache, edata);
547
548 if (_ocache->c_shdr->sh_type == M_REL_SHT_TYPE)
549 update_reloc(ocache, _ocache, icache, _icache, oehdr->e_shnum);
550 }
551
552 if (elf_update(oelf, ELF_C_WRITE) == -1)
553 return (elferr("elf_update"));
554
555 elf_end(oelf);
556 elf_end(ielf);
557 return (0);
558 }