1 /*
2 * Copyright (c) 1995
3 * Ted Lemon (hereinafter referred to as the author)
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 /* elf2ecoff.c
30
31 This program converts an elf executable to an ECOFF executable.
32 No symbol table is retained. This is useful primarily in building
33 net-bootable kernels for machines (e.g., DECstation and Alpha) which
34 only support the ECOFF object file format. */
35
36 #include <stdio.h>
37 #include <string.h>
38 #include <errno.h>
39 #include <sys/types.h>
40 #include <fcntl.h>
41 #include <unistd.h>
42 #include <elf.h>
43 #include <limits.h>
44 #include <netinet/in.h>
45 #include <stdlib.h>
46 #include <stdint.h>
47 #include <inttypes.h>
48
49 #include "ecoff.h"
50
51 /*
52 * Some extra ELF definitions
53 */
54 #define PT_MIPS_REGINFO 0x70000000 /* Register usage information */
55 #define PT_MIPS_ABIFLAGS 0x70000003 /* Records ABI related flags */
56
57 /* -------------------------------------------------------------------- */
58
59 struct sect {
60 uint32_t vaddr;
61 uint32_t len;
62 };
63
64 int *symTypeTable;
65 int must_convert_endian;
66 int format_bigendian;
67
copy(int out,int in,off_t offset,off_t size)68 static void copy(int out, int in, off_t offset, off_t size)
69 {
70 char ibuf[4096];
71 int remaining, cur, count;
72
73 /* Go to the start of the ELF symbol table... */
74 if (lseek(in, offset, SEEK_SET) < 0) {
75 perror("copy: lseek");
76 exit(1);
77 }
78
79 remaining = size;
80 while (remaining) {
81 cur = remaining;
82 if (cur > sizeof ibuf)
83 cur = sizeof ibuf;
84 remaining -= cur;
85 if ((count = read(in, ibuf, cur)) != cur) {
86 fprintf(stderr, "copy: read: %s\n",
87 count ? strerror(errno) :
88 "premature end of file");
89 exit(1);
90 }
91 if ((count = write(out, ibuf, cur)) != cur) {
92 perror("copy: write");
93 exit(1);
94 }
95 }
96 }
97
98 /*
99 * Combine two segments, which must be contiguous. If pad is true, it's
100 * okay for there to be padding between.
101 */
combine(struct sect * base,struct sect * new,int pad)102 static void combine(struct sect *base, struct sect *new, int pad)
103 {
104 if (!base->len)
105 *base = *new;
106 else if (new->len) {
107 if (base->vaddr + base->len != new->vaddr) {
108 if (pad)
109 base->len = new->vaddr - base->vaddr;
110 else {
111 fprintf(stderr,
112 "Non-contiguous data can't be converted.\n");
113 exit(1);
114 }
115 }
116 base->len += new->len;
117 }
118 }
119
phcmp(const void * v1,const void * v2)120 static int phcmp(const void *v1, const void *v2)
121 {
122 const Elf32_Phdr *h1 = v1;
123 const Elf32_Phdr *h2 = v2;
124
125 if (h1->p_vaddr > h2->p_vaddr)
126 return 1;
127 else if (h1->p_vaddr < h2->p_vaddr)
128 return -1;
129 else
130 return 0;
131 }
132
saveRead(int file,off_t offset,off_t len,char * name)133 static char *saveRead(int file, off_t offset, off_t len, char *name)
134 {
135 char *tmp;
136 int count;
137 off_t off;
138 if ((off = lseek(file, offset, SEEK_SET)) < 0) {
139 fprintf(stderr, "%s: fseek: %s\n", name, strerror(errno));
140 exit(1);
141 }
142 if (!(tmp = (char *) malloc(len))) {
143 fprintf(stderr, "%s: Can't allocate %ld bytes.\n", name,
144 len);
145 exit(1);
146 }
147 count = read(file, tmp, len);
148 if (count != len) {
149 fprintf(stderr, "%s: read: %s.\n",
150 name,
151 count ? strerror(errno) : "End of file reached");
152 exit(1);
153 }
154 return tmp;
155 }
156
157 #define swab16(x) \
158 ((uint16_t)( \
159 (((uint16_t)(x) & (uint16_t)0x00ffU) << 8) | \
160 (((uint16_t)(x) & (uint16_t)0xff00U) >> 8) ))
161
162 #define swab32(x) \
163 ((unsigned int)( \
164 (((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) | \
165 (((uint32_t)(x) & (uint32_t)0x0000ff00UL) << 8) | \
166 (((uint32_t)(x) & (uint32_t)0x00ff0000UL) >> 8) | \
167 (((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24) ))
168
convert_elf_hdr(Elf32_Ehdr * e)169 static void convert_elf_hdr(Elf32_Ehdr * e)
170 {
171 e->e_type = swab16(e->e_type);
172 e->e_machine = swab16(e->e_machine);
173 e->e_version = swab32(e->e_version);
174 e->e_entry = swab32(e->e_entry);
175 e->e_phoff = swab32(e->e_phoff);
176 e->e_shoff = swab32(e->e_shoff);
177 e->e_flags = swab32(e->e_flags);
178 e->e_ehsize = swab16(e->e_ehsize);
179 e->e_phentsize = swab16(e->e_phentsize);
180 e->e_phnum = swab16(e->e_phnum);
181 e->e_shentsize = swab16(e->e_shentsize);
182 e->e_shnum = swab16(e->e_shnum);
183 e->e_shstrndx = swab16(e->e_shstrndx);
184 }
185
convert_elf_phdrs(Elf32_Phdr * p,int num)186 static void convert_elf_phdrs(Elf32_Phdr * p, int num)
187 {
188 int i;
189
190 for (i = 0; i < num; i++, p++) {
191 p->p_type = swab32(p->p_type);
192 p->p_offset = swab32(p->p_offset);
193 p->p_vaddr = swab32(p->p_vaddr);
194 p->p_paddr = swab32(p->p_paddr);
195 p->p_filesz = swab32(p->p_filesz);
196 p->p_memsz = swab32(p->p_memsz);
197 p->p_flags = swab32(p->p_flags);
198 p->p_align = swab32(p->p_align);
199 }
200
201 }
202
convert_elf_shdrs(Elf32_Shdr * s,int num)203 static void convert_elf_shdrs(Elf32_Shdr * s, int num)
204 {
205 int i;
206
207 for (i = 0; i < num; i++, s++) {
208 s->sh_name = swab32(s->sh_name);
209 s->sh_type = swab32(s->sh_type);
210 s->sh_flags = swab32(s->sh_flags);
211 s->sh_addr = swab32(s->sh_addr);
212 s->sh_offset = swab32(s->sh_offset);
213 s->sh_size = swab32(s->sh_size);
214 s->sh_link = swab32(s->sh_link);
215 s->sh_info = swab32(s->sh_info);
216 s->sh_addralign = swab32(s->sh_addralign);
217 s->sh_entsize = swab32(s->sh_entsize);
218 }
219 }
220
convert_ecoff_filehdr(struct filehdr * f)221 static void convert_ecoff_filehdr(struct filehdr *f)
222 {
223 f->f_magic = swab16(f->f_magic);
224 f->f_nscns = swab16(f->f_nscns);
225 f->f_timdat = swab32(f->f_timdat);
226 f->f_symptr = swab32(f->f_symptr);
227 f->f_nsyms = swab32(f->f_nsyms);
228 f->f_opthdr = swab16(f->f_opthdr);
229 f->f_flags = swab16(f->f_flags);
230 }
231
convert_ecoff_aouthdr(struct aouthdr * a)232 static void convert_ecoff_aouthdr(struct aouthdr *a)
233 {
234 a->magic = swab16(a->magic);
235 a->vstamp = swab16(a->vstamp);
236 a->tsize = swab32(a->tsize);
237 a->dsize = swab32(a->dsize);
238 a->bsize = swab32(a->bsize);
239 a->entry = swab32(a->entry);
240 a->text_start = swab32(a->text_start);
241 a->data_start = swab32(a->data_start);
242 a->bss_start = swab32(a->bss_start);
243 a->gprmask = swab32(a->gprmask);
244 a->cprmask[0] = swab32(a->cprmask[0]);
245 a->cprmask[1] = swab32(a->cprmask[1]);
246 a->cprmask[2] = swab32(a->cprmask[2]);
247 a->cprmask[3] = swab32(a->cprmask[3]);
248 a->gp_value = swab32(a->gp_value);
249 }
250
convert_ecoff_esecs(struct scnhdr * s,int num)251 static void convert_ecoff_esecs(struct scnhdr *s, int num)
252 {
253 int i;
254
255 for (i = 0; i < num; i++, s++) {
256 s->s_paddr = swab32(s->s_paddr);
257 s->s_vaddr = swab32(s->s_vaddr);
258 s->s_size = swab32(s->s_size);
259 s->s_scnptr = swab32(s->s_scnptr);
260 s->s_relptr = swab32(s->s_relptr);
261 s->s_lnnoptr = swab32(s->s_lnnoptr);
262 s->s_nreloc = swab16(s->s_nreloc);
263 s->s_nlnno = swab16(s->s_nlnno);
264 s->s_flags = swab32(s->s_flags);
265 }
266 }
267
main(int argc,char * argv[])268 int main(int argc, char *argv[])
269 {
270 Elf32_Ehdr ex;
271 Elf32_Phdr *ph;
272 Elf32_Shdr *sh;
273 int i, pad;
274 struct sect text, data, bss;
275 struct filehdr efh;
276 struct aouthdr eah;
277 struct scnhdr esecs[6];
278 int infile, outfile;
279 uint32_t cur_vma = UINT32_MAX;
280 int addflag = 0;
281 int nosecs;
282
283 text.len = data.len = bss.len = 0;
284 text.vaddr = data.vaddr = bss.vaddr = 0;
285
286 /* Check args... */
287 if (argc < 3 || argc > 4) {
288 usage:
289 fprintf(stderr,
290 "usage: elf2ecoff <elf executable> <ecoff executable> [-a]\n");
291 exit(1);
292 }
293 if (argc == 4) {
294 if (strcmp(argv[3], "-a"))
295 goto usage;
296 addflag = 1;
297 }
298
299 /* Try the input file... */
300 if ((infile = open(argv[1], O_RDONLY)) < 0) {
301 fprintf(stderr, "Can't open %s for read: %s\n",
302 argv[1], strerror(errno));
303 exit(1);
304 }
305
306 /* Read the header, which is at the beginning of the file... */
307 i = read(infile, &ex, sizeof ex);
308 if (i != sizeof ex) {
309 fprintf(stderr, "ex: %s: %s.\n",
310 argv[1],
311 i ? strerror(errno) : "End of file reached");
312 exit(1);
313 }
314
315 if (ex.e_ident[EI_DATA] == ELFDATA2MSB)
316 format_bigendian = 1;
317
318 if (ntohs(0xaa55) == 0xaa55) {
319 if (!format_bigendian)
320 must_convert_endian = 1;
321 } else {
322 if (format_bigendian)
323 must_convert_endian = 1;
324 }
325 if (must_convert_endian)
326 convert_elf_hdr(&ex);
327
328 /* Read the program headers... */
329 ph = (Elf32_Phdr *) saveRead(infile, ex.e_phoff,
330 ex.e_phnum * sizeof(Elf32_Phdr),
331 "ph");
332 if (must_convert_endian)
333 convert_elf_phdrs(ph, ex.e_phnum);
334 /* Read the section headers... */
335 sh = (Elf32_Shdr *) saveRead(infile, ex.e_shoff,
336 ex.e_shnum * sizeof(Elf32_Shdr),
337 "sh");
338 if (must_convert_endian)
339 convert_elf_shdrs(sh, ex.e_shnum);
340
341 /* Figure out if we can cram the program header into an ECOFF
342 header... Basically, we can't handle anything but loadable
343 segments, but we can ignore some kinds of segments. We can't
344 handle holes in the address space. Segments may be out of order,
345 so we sort them first. */
346
347 qsort(ph, ex.e_phnum, sizeof(Elf32_Phdr), phcmp);
348
349 for (i = 0; i < ex.e_phnum; i++) {
350 /* Section types we can ignore... */
351 switch (ph[i].p_type) {
352 case PT_NULL:
353 case PT_NOTE:
354 case PT_PHDR:
355 case PT_MIPS_REGINFO:
356 case PT_MIPS_ABIFLAGS:
357 continue;
358
359 case PT_LOAD:
360 /* Writable (data) segment? */
361 if (ph[i].p_flags & PF_W) {
362 struct sect ndata, nbss;
363
364 ndata.vaddr = ph[i].p_vaddr;
365 ndata.len = ph[i].p_filesz;
366 nbss.vaddr = ph[i].p_vaddr + ph[i].p_filesz;
367 nbss.len = ph[i].p_memsz - ph[i].p_filesz;
368
369 combine(&data, &ndata, 0);
370 combine(&bss, &nbss, 1);
371 } else {
372 struct sect ntxt;
373
374 ntxt.vaddr = ph[i].p_vaddr;
375 ntxt.len = ph[i].p_filesz;
376
377 combine(&text, &ntxt, 0);
378 }
379 /* Remember the lowest segment start address. */
380 if (ph[i].p_vaddr < cur_vma)
381 cur_vma = ph[i].p_vaddr;
382 break;
383
384 default:
385 /* Section types we can't handle... */
386 fprintf(stderr,
387 "Program header %d type %d can't be converted.\n",
388 ex.e_phnum, ph[i].p_type);
389 exit(1);
390 }
391 }
392
393 /* Sections must be in order to be converted... */
394 if (text.vaddr > data.vaddr || data.vaddr > bss.vaddr ||
395 text.vaddr + text.len > data.vaddr
396 || data.vaddr + data.len > bss.vaddr) {
397 fprintf(stderr,
398 "Sections ordering prevents a.out conversion.\n");
399 exit(1);
400 }
401
402 /* If there's a data section but no text section, then the loader
403 combined everything into one section. That needs to be the
404 text section, so just make the data section zero length following
405 text. */
406 if (data.len && !text.len) {
407 text = data;
408 data.vaddr = text.vaddr + text.len;
409 data.len = 0;
410 }
411
412 /* If there is a gap between text and data, we'll fill it when we copy
413 the data, so update the length of the text segment as represented in
414 a.out to reflect that, since a.out doesn't allow gaps in the program
415 address space. */
416 if (text.vaddr + text.len < data.vaddr)
417 text.len = data.vaddr - text.vaddr;
418
419 /* We now have enough information to cons up an a.out header... */
420 eah.magic = OMAGIC;
421 eah.vstamp = 200;
422 eah.tsize = text.len;
423 eah.dsize = data.len;
424 eah.bsize = bss.len;
425 eah.entry = ex.e_entry;
426 eah.text_start = text.vaddr;
427 eah.data_start = data.vaddr;
428 eah.bss_start = bss.vaddr;
429 eah.gprmask = 0xf3fffffe;
430 memset(&eah.cprmask, '\0', sizeof eah.cprmask);
431 eah.gp_value = 0; /* unused. */
432
433 if (format_bigendian)
434 efh.f_magic = MIPSEBMAGIC;
435 else
436 efh.f_magic = MIPSELMAGIC;
437 if (addflag)
438 nosecs = 6;
439 else
440 nosecs = 3;
441 efh.f_nscns = nosecs;
442 efh.f_timdat = 0; /* bogus */
443 efh.f_symptr = 0;
444 efh.f_nsyms = 0;
445 efh.f_opthdr = sizeof eah;
446 efh.f_flags = 0x100f; /* Stripped, not sharable. */
447
448 memset(esecs, 0, sizeof esecs);
449 strcpy(esecs[0].s_name, ".text");
450 strcpy(esecs[1].s_name, ".data");
451 strcpy(esecs[2].s_name, ".bss");
452 if (addflag) {
453 strcpy(esecs[3].s_name, ".rdata");
454 strcpy(esecs[4].s_name, ".sdata");
455 strcpy(esecs[5].s_name, ".sbss");
456 }
457 esecs[0].s_paddr = esecs[0].s_vaddr = eah.text_start;
458 esecs[1].s_paddr = esecs[1].s_vaddr = eah.data_start;
459 esecs[2].s_paddr = esecs[2].s_vaddr = eah.bss_start;
460 if (addflag) {
461 esecs[3].s_paddr = esecs[3].s_vaddr = 0;
462 esecs[4].s_paddr = esecs[4].s_vaddr = 0;
463 esecs[5].s_paddr = esecs[5].s_vaddr = 0;
464 }
465 esecs[0].s_size = eah.tsize;
466 esecs[1].s_size = eah.dsize;
467 esecs[2].s_size = eah.bsize;
468 if (addflag) {
469 esecs[3].s_size = 0;
470 esecs[4].s_size = 0;
471 esecs[5].s_size = 0;
472 }
473 esecs[0].s_scnptr = N_TXTOFF(efh, eah);
474 esecs[1].s_scnptr = N_DATOFF(efh, eah);
475 #define ECOFF_SEGMENT_ALIGNMENT(a) 0x10
476 #define ECOFF_ROUND(s, a) (((s)+(a)-1)&~((a)-1))
477 esecs[2].s_scnptr = esecs[1].s_scnptr +
478 ECOFF_ROUND(esecs[1].s_size, ECOFF_SEGMENT_ALIGNMENT(&eah));
479 if (addflag) {
480 esecs[3].s_scnptr = 0;
481 esecs[4].s_scnptr = 0;
482 esecs[5].s_scnptr = 0;
483 }
484 esecs[0].s_relptr = esecs[1].s_relptr = esecs[2].s_relptr = 0;
485 esecs[0].s_lnnoptr = esecs[1].s_lnnoptr = esecs[2].s_lnnoptr = 0;
486 esecs[0].s_nreloc = esecs[1].s_nreloc = esecs[2].s_nreloc = 0;
487 esecs[0].s_nlnno = esecs[1].s_nlnno = esecs[2].s_nlnno = 0;
488 if (addflag) {
489 esecs[3].s_relptr = esecs[4].s_relptr
490 = esecs[5].s_relptr = 0;
491 esecs[3].s_lnnoptr = esecs[4].s_lnnoptr
492 = esecs[5].s_lnnoptr = 0;
493 esecs[3].s_nreloc = esecs[4].s_nreloc = esecs[5].s_nreloc =
494 0;
495 esecs[3].s_nlnno = esecs[4].s_nlnno = esecs[5].s_nlnno = 0;
496 }
497 esecs[0].s_flags = 0x20;
498 esecs[1].s_flags = 0x40;
499 esecs[2].s_flags = 0x82;
500 if (addflag) {
501 esecs[3].s_flags = 0x100;
502 esecs[4].s_flags = 0x200;
503 esecs[5].s_flags = 0x400;
504 }
505
506 /* Make the output file... */
507 if ((outfile = open(argv[2], O_WRONLY | O_CREAT, 0777)) < 0) {
508 fprintf(stderr, "Unable to create %s: %s\n", argv[2],
509 strerror(errno));
510 exit(1);
511 }
512
513 if (must_convert_endian)
514 convert_ecoff_filehdr(&efh);
515 /* Write the headers... */
516 i = write(outfile, &efh, sizeof efh);
517 if (i != sizeof efh) {
518 perror("efh: write");
519 exit(1);
520
521 for (i = 0; i < nosecs; i++) {
522 printf
523 ("Section %d: %s phys %"PRIx32" size %"PRIx32"\t file offset %"PRIx32"\n",
524 i, esecs[i].s_name, esecs[i].s_paddr,
525 esecs[i].s_size, esecs[i].s_scnptr);
526 }
527 }
528 fprintf(stderr, "wrote %d byte file header.\n", i);
529
530 if (must_convert_endian)
531 convert_ecoff_aouthdr(&eah);
532 i = write(outfile, &eah, sizeof eah);
533 if (i != sizeof eah) {
534 perror("eah: write");
535 exit(1);
536 }
537 fprintf(stderr, "wrote %d byte a.out header.\n", i);
538
539 if (must_convert_endian)
540 convert_ecoff_esecs(&esecs[0], nosecs);
541 i = write(outfile, &esecs, nosecs * sizeof(struct scnhdr));
542 if (i != nosecs * sizeof(struct scnhdr)) {
543 perror("esecs: write");
544 exit(1);
545 }
546 fprintf(stderr, "wrote %d bytes of section headers.\n", i);
547
548 pad = (sizeof(efh) + sizeof(eah) + nosecs * sizeof(struct scnhdr)) & 15;
549 if (pad) {
550 pad = 16 - pad;
551 i = write(outfile, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0", pad);
552 if (i < 0) {
553 perror("ipad: write");
554 exit(1);
555 }
556 fprintf(stderr, "wrote %d byte pad.\n", i);
557 }
558
559 /*
560 * Copy the loadable sections. Zero-fill any gaps less than 64k;
561 * complain about any zero-filling, and die if we're asked to zero-fill
562 * more than 64k.
563 */
564 for (i = 0; i < ex.e_phnum; i++) {
565 /* Unprocessable sections were handled above, so just verify that
566 the section can be loaded before copying. */
567 if (ph[i].p_type == PT_LOAD && ph[i].p_filesz) {
568 if (cur_vma != ph[i].p_vaddr) {
569 uint32_t gap = ph[i].p_vaddr - cur_vma;
570 char obuf[1024];
571 if (gap > 65536) {
572 fprintf(stderr,
573 "Intersegment gap (%"PRId32" bytes) too large.\n",
574 gap);
575 exit(1);
576 }
577 fprintf(stderr,
578 "Warning: %d byte intersegment gap.\n",
579 gap);
580 memset(obuf, 0, sizeof obuf);
581 while (gap) {
582 int count =
583 write(outfile, obuf,
584 (gap >
585 sizeof obuf ? sizeof
586 obuf : gap));
587 if (count < 0) {
588 fprintf(stderr,
589 "Error writing gap: %s\n",
590 strerror(errno));
591 exit(1);
592 }
593 gap -= count;
594 }
595 }
596 fprintf(stderr, "writing %d bytes...\n",
597 ph[i].p_filesz);
598 copy(outfile, infile, ph[i].p_offset,
599 ph[i].p_filesz);
600 cur_vma = ph[i].p_vaddr + ph[i].p_filesz;
601 }
602 }
603
604 /*
605 * Write a page of padding for boot PROMS that read entire pages.
606 * Without this, they may attempt to read past the end of the
607 * data section, incur an error, and refuse to boot.
608 */
609 {
610 char obuf[4096];
611 memset(obuf, 0, sizeof obuf);
612 if (write(outfile, obuf, sizeof(obuf)) != sizeof(obuf)) {
613 fprintf(stderr, "Error writing PROM padding: %s\n",
614 strerror(errno));
615 exit(1);
616 }
617 }
618
619 /* Looks like we won... */
620 exit(0);
621 }
622
