1 /*
2 * Copyright (c) 2004 Ian Dowse <iedowse@freebsd.org>
3 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
4 * Copyright (c) 1998 Peter Wemm <peter@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 #include <sys/cdefs.h>
30
31 #include <sys/param.h>
32 #include <sys/exec.h>
33 #include <sys/linker.h>
34 #include <sys/module.h>
35 #include <inttypes.h>
36 #include <string.h>
37 #include <machine/elf.h>
38 #include <stand.h>
39 #define FREEBSD_ELF
40 #include <link.h>
41
42 #include "bootstrap.h"
43
44 #define COPYOUT(s, d, l) archsw.arch_copyout((vm_offset_t)(s), d, l)
45
46 #if defined(__i386__) && __ELF_WORD_SIZE == 64
47 #undef ELF_TARG_CLASS
48 #undef ELF_TARG_MACH
49 #define ELF_TARG_CLASS ELFCLASS64
50 #define ELF_TARG_MACH EM_X86_64
51 #endif
52
53 typedef struct elf_file {
54 Elf_Ehdr hdr;
55 Elf_Shdr *e_shdr;
56
57 int symtabindex; /* Index of symbol table */
58 int shstrindex; /* Index of section name string table */
59
60 int fd;
61 vm_offset_t off;
62 } *elf_file_t;
63
64 static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef,
65 uint64_t loadaddr);
66 static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef,
67 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp);
68 static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef,
69 Elf_Addr p, void *val, size_t len);
70 static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp,
71 elf_file_t ef);
72 static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx);
73
74 const char *__elfN(obj_kerneltype) = "elf kernel";
75 const char *__elfN(obj_moduletype) = "elf obj module";
76
77 /*
78 * Attempt to load the file (file) as an ELF module. It will be stored at
79 * (dest), and a pointer to a module structure describing the loaded object
80 * will be saved in (result).
81 */
82 int
__elfN(obj_loadfile)83 __elfN(obj_loadfile)(char *filename, uint64_t dest,
84 struct preloaded_file **result)
85 {
86 struct preloaded_file *fp, *kfp;
87 struct elf_file ef;
88 Elf_Ehdr *hdr;
89 int err;
90 ssize_t bytes_read;
91
92 fp = NULL;
93 bzero(&ef, sizeof (struct elf_file));
94
95 /*
96 * Open the image, read and validate the ELF header
97 */
98 if (filename == NULL) /* can't handle nameless */
99 return (EFTYPE);
100 if ((ef.fd = open(filename, O_RDONLY)) == -1)
101 return (errno);
102
103 hdr = &ef.hdr;
104 bytes_read = read(ef.fd, hdr, sizeof (*hdr));
105 if (bytes_read != sizeof (*hdr)) {
106 err = EFTYPE; /* could be EIO, but may be small file */
107 goto oerr;
108 }
109
110 /* Is it ELF? */
111 if (!IS_ELF(*hdr)) {
112 err = EFTYPE;
113 goto oerr;
114 }
115 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */
116 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
117 hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */
118 hdr->e_version != EV_CURRENT ||
119 hdr->e_machine != ELF_TARG_MACH || /* Machine ? */
120 hdr->e_type != ET_REL) {
121 err = EFTYPE;
122 goto oerr;
123 }
124
125 if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 ||
126 hdr->e_shentsize != sizeof (Elf_Shdr)) {
127 err = EFTYPE;
128 goto oerr;
129 }
130
131 kfp = file_findfile(NULL, __elfN(obj_kerneltype));
132 if (kfp == NULL) {
133 printf("elf" __XSTRING(__ELF_WORD_SIZE)
134 "_obj_loadfile: can't load module before kernel\n");
135 err = EPERM;
136 goto oerr;
137 }
138
139 if (archsw.arch_loadaddr != NULL)
140 dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest);
141 else
142 dest = roundup(dest, PAGE_SIZE);
143
144 /*
145 * Ok, we think we should handle this.
146 */
147 fp = file_alloc();
148 if (fp == NULL) {
149 printf("elf" __XSTRING(__ELF_WORD_SIZE)
150 "_obj_loadfile: cannot allocate module info\n");
151 err = EPERM;
152 goto out;
153 }
154 fp->f_name = strdup(filename);
155 fp->f_type = strdup(__elfN(obj_moduletype));
156
157 printf("%s ", filename);
158
159 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest);
160 if (fp->f_size == 0 || fp->f_addr == 0)
161 goto ioerr;
162
163 /* save exec header as metadata */
164 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof (*hdr), hdr);
165
166 /* Load OK, return module pointer */
167 *result = (struct preloaded_file *)fp;
168 err = 0;
169 goto out;
170
171 ioerr:
172 err = EIO;
173 oerr:
174 file_discard(fp);
175 out:
176 (void) close(ef.fd);
177 if (ef.e_shdr != NULL)
178 free(ef.e_shdr);
179
180 return (err);
181 }
182
183 /*
184 * With the file (fd) open on the image, and (ehdr) containing
185 * the Elf header, load the image at (off)
186 */
187 static int
__elfN(obj_loadimage)188 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, uint64_t off)
189 {
190 Elf_Ehdr *hdr;
191 Elf_Shdr *shdr, *cshdr, *lshdr;
192 vm_offset_t firstaddr, lastaddr;
193 int i, nsym, res, ret, shdrbytes, symstrindex;
194
195 ret = 0;
196 firstaddr = lastaddr = (vm_offset_t)off;
197 hdr = &ef->hdr;
198 ef->off = (vm_offset_t)off;
199
200 /* Read in the section headers. */
201 shdrbytes = hdr->e_shnum * hdr->e_shentsize;
202 shdr = alloc_pread(ef->fd, (off_t)hdr->e_shoff, shdrbytes);
203 if (shdr == NULL) {
204 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
205 "_obj_loadimage: read section headers failed\n");
206 goto out;
207 }
208 ef->e_shdr = shdr;
209
210 /*
211 * Decide where to load everything, but don't read it yet.
212 * We store the load address as a non-zero sh_addr value.
213 * Start with the code/data and bss.
214 */
215 for (i = 0; i < hdr->e_shnum; i++)
216 shdr[i].sh_addr = 0;
217 for (i = 0; i < hdr->e_shnum; i++) {
218 if (shdr[i].sh_size == 0)
219 continue;
220 switch (shdr[i].sh_type) {
221 case SHT_PROGBITS:
222 case SHT_NOBITS:
223 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
224 shdr[i].sh_addr = (Elf_Addr)lastaddr;
225 lastaddr += shdr[i].sh_size;
226 break;
227 }
228 }
229
230 /* Symbols. */
231 nsym = 0;
232 for (i = 0; i < hdr->e_shnum; i++) {
233 switch (shdr[i].sh_type) {
234 case SHT_SYMTAB:
235 nsym++;
236 ef->symtabindex = i;
237 shdr[i].sh_addr = (Elf_Addr)lastaddr;
238 lastaddr += shdr[i].sh_size;
239 break;
240 }
241 }
242 if (nsym != 1) {
243 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
244 "_obj_loadimage: file has no valid symbol table\n");
245 goto out;
246 }
247 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign);
248 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr;
249 lastaddr += shdr[ef->symtabindex].sh_size;
250
251 symstrindex = shdr[ef->symtabindex].sh_link;
252 if (symstrindex < 0 || symstrindex >= hdr->e_shnum ||
253 shdr[symstrindex].sh_type != SHT_STRTAB) {
254 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
255 "_obj_loadimage: file has invalid symbol strings\n");
256 goto out;
257 }
258 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign);
259 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr;
260 lastaddr += shdr[symstrindex].sh_size;
261
262 /* Section names. */
263 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum ||
264 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
265 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
266 "_obj_loadimage: file has no section names\n");
267 goto out;
268 }
269 ef->shstrindex = hdr->e_shstrndx;
270 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign);
271 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr;
272 lastaddr += shdr[ef->shstrindex].sh_size;
273
274 /* Relocation tables. */
275 for (i = 0; i < hdr->e_shnum; i++) {
276 switch (shdr[i].sh_type) {
277 case SHT_REL:
278 case SHT_RELA:
279 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
280 shdr[i].sh_addr = (Elf_Addr)lastaddr;
281 lastaddr += shdr[i].sh_size;
282 break;
283 }
284 }
285
286 /* Clear the whole area, including bss regions. */
287 kern_bzero(firstaddr, lastaddr - firstaddr);
288
289 /* Figure section with the lowest file offset we haven't loaded yet. */
290 for (cshdr = NULL; /* none */; /* none */) {
291 /*
292 * Find next section to load. The complexity of this loop is
293 * O(n^2), but with the number of sections being typically
294 * small, we do not care.
295 */
296 lshdr = cshdr;
297
298 for (i = 0; i < hdr->e_shnum; i++) {
299 if (shdr[i].sh_addr == 0 ||
300 shdr[i].sh_type == SHT_NOBITS)
301 continue;
302 /* Skip sections that were loaded already. */
303 if (lshdr != NULL &&
304 lshdr->sh_offset >= shdr[i].sh_offset)
305 continue;
306 /* Find section with smallest offset. */
307 if (cshdr == lshdr ||
308 cshdr->sh_offset > shdr[i].sh_offset)
309 cshdr = &shdr[i];
310 }
311
312 if (cshdr == lshdr)
313 break;
314
315 if (kern_pread(ef->fd, (vm_offset_t)cshdr->sh_addr,
316 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) {
317 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
318 "_obj_loadimage: read failed\n");
319 goto out;
320 }
321 }
322
323 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr);
324
325 res = __elfN(obj_parse_modmetadata)(fp, ef);
326 if (res != 0)
327 goto out;
328
329 ret = lastaddr - firstaddr;
330 fp->f_addr = firstaddr;
331
332 printf("size 0x%lx at 0x%lx", (ulong_t)ret, (ulong_t)firstaddr);
333
334 out:
335 printf("\n");
336 return (ret);
337 }
338
339 #if defined(__i386__) && __ELF_WORD_SIZE == 64
340 struct mod_metadata64 {
341 int md_version; /* structure version MDTV_* */
342 int md_type; /* type of entry MDT_* */
343 uint64_t md_data; /* specific data */
344 uint64_t md_cval; /* common string label */
345 };
346 #endif
347
348 int
__elfN(obj_parse_modmetadata)349 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
350 {
351 struct mod_metadata md;
352 #if defined(__i386__) && __ELF_WORD_SIZE == 64
353 struct mod_metadata64 md64;
354 #endif
355 struct mod_depend *mdepend;
356 struct mod_version mver;
357 char *s;
358 int error, modcnt, minfolen;
359 Elf_Addr v, p, p_stop;
360
361 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop,
362 &modcnt) != 0)
363 return (0);
364
365 modcnt = 0;
366 while (p < p_stop) {
367 (void) COPYOUT(p, &v, sizeof (v));
368 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof (v));
369 if (error != 0)
370 return (error);
371 #if defined(__i386__) && __ELF_WORD_SIZE == 64
372 (void) COPYOUT(v, &md64, sizeof (md64));
373 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof (md64));
374 if (error != 0)
375 return (error);
376 md.md_version = md64.md_version;
377 md.md_type = md64.md_type;
378 md.md_cval = (const char *)(uintptr_t)md64.md_cval;
379 md.md_data = (void *)(uintptr_t)md64.md_data;
380 #else
381 (void) COPYOUT(v, &md, sizeof (md));
382 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof (md));
383 if (error != 0)
384 return (error);
385 #endif
386 p += sizeof (Elf_Addr);
387 switch (md.md_type) {
388 case MDT_DEPEND:
389 s = strdupout((vm_offset_t)md.md_cval);
390 minfolen = sizeof (*mdepend) + strlen(s) + 1;
391 mdepend = malloc(minfolen);
392 if (mdepend == NULL)
393 return (ENOMEM);
394 (void) COPYOUT((vm_offset_t)md.md_data, mdepend,
395 sizeof (*mdepend));
396 (void) strcpy((char *)(mdepend + 1), s);
397 free(s);
398 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen,
399 mdepend);
400 free(mdepend);
401 break;
402 case MDT_VERSION:
403 s = strdupout((vm_offset_t)md.md_cval);
404 (void) COPYOUT((vm_offset_t)md.md_data, &mver,
405 sizeof (mver));
406 (void) file_addmodule(fp, s, mver.mv_version, NULL);
407 free(s);
408 modcnt++;
409 break;
410 case MDT_MODULE:
411 case MDT_PNP_INFO:
412 break;
413 default:
414 printf("unknown type %d\n", md.md_type);
415 break;
416 }
417 }
418 return (0);
419 }
420
421 static int
__elfN(obj_lookup_set)422 __elfN(obj_lookup_set)(struct preloaded_file *fp __unused, elf_file_t ef,
423 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp)
424 {
425 Elf_Ehdr *hdr;
426 Elf_Shdr *shdr;
427 char *p;
428 vm_offset_t shstrtab;
429 int i;
430
431 hdr = &ef->hdr;
432 shdr = ef->e_shdr;
433 shstrtab = shdr[ef->shstrindex].sh_addr;
434
435 for (i = 0; i < hdr->e_shnum; i++) {
436 if (shdr[i].sh_type != SHT_PROGBITS)
437 continue;
438 if (shdr[i].sh_name == 0)
439 continue;
440 p = strdupout(shstrtab + shdr[i].sh_name);
441 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) {
442 *startp = shdr[i].sh_addr;
443 *stopp = shdr[i].sh_addr + shdr[i].sh_size;
444 *countp = (*stopp - *startp) / sizeof (Elf_Addr);
445 free(p);
446 return (0);
447 }
448 free(p);
449 }
450
451 return (ESRCH);
452 }
453
454 /*
455 * Apply any intra-module relocations to the value. p is the load address
456 * of the value and val/len is the value to be modified. This does NOT modify
457 * the image in-place, because this is done by kern_linker later on.
458 */
459 static int
__elfN(obj_reloc_ptr)460 __elfN(obj_reloc_ptr)(struct preloaded_file *mp __unused, elf_file_t ef,
461 Elf_Addr p, void *val, size_t len)
462 {
463 Elf_Ehdr *hdr;
464 Elf_Shdr *shdr;
465 Elf_Addr off = p;
466 Elf_Addr base;
467 Elf_Rela a, *abase;
468 Elf_Rel r, *rbase;
469 int error, i, j, nrel, nrela;
470
471 hdr = &ef->hdr;
472 shdr = ef->e_shdr;
473
474 for (i = 0; i < hdr->e_shnum; i++) {
475 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL)
476 continue;
477 base = shdr[shdr[i].sh_info].sh_addr;
478 if (base == 0 || shdr[i].sh_addr == 0)
479 continue;
480 if (off < base || off + len > base +
481 shdr[shdr[i].sh_info].sh_size)
482 continue;
483
484 switch (shdr[i].sh_type) {
485 case SHT_RELA:
486 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr;
487
488 nrela = shdr[i].sh_size / sizeof (Elf_Rela);
489 for (j = 0; j < nrela; j++) {
490 (void) COPYOUT(abase + j, &a, sizeof (a));
491
492 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
493 &a, ELF_RELOC_RELA, base, off, val, len);
494 if (error != 0)
495 return (error);
496 }
497 break;
498 case SHT_REL:
499 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr;
500
501 nrel = shdr[i].sh_size / sizeof (Elf_Rel);
502 for (j = 0; j < nrel; j++) {
503 (void) COPYOUT(rbase + j, &r, sizeof (r));
504
505 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
506 &r, ELF_RELOC_REL, base, off, val, len);
507 if (error != 0)
508 return (error);
509 }
510 break;
511 }
512 }
513 return (0);
514 }
515
516 /* Look up the address of a specified symbol. */
517 static Elf_Addr
__elfN(obj_symaddr)518 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx)
519 {
520 Elf_Sym sym;
521 Elf_Addr base;
522
523 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof (Elf_Sym))
524 return (0);
525 (void) COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr +
526 symidx * sizeof (Elf_Sym), &sym, sizeof (sym));
527 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum)
528 return (0);
529 base = ef->e_shdr[sym.st_shndx].sh_addr;
530 if (base == 0)
531 return (0);
532 return (base + sym.st_value);
533 }
534