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 __FBSDID("$FreeBSD$");
31
32 #include <sys/param.h>
33 #include <sys/exec.h>
34 #include <sys/linker.h>
35 #include <sys/module.h>
36 #include <inttypes.h>
37 #include <string.h>
38 #include <machine/elf.h>
39 #include <stand.h>
40 #define FREEBSD_ELF
41 #include <link.h>
42
43 #include "bootstrap.h"
44
45 #define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l)
46
47 #if defined(__i386__) && __ELF_WORD_SIZE == 64
48 #undef ELF_TARG_CLASS
49 #undef ELF_TARG_MACH
50 #define ELF_TARG_CLASS ELFCLASS64
51 #define ELF_TARG_MACH EM_X86_64
52 #endif
53
54 typedef struct elf_file {
55 Elf_Ehdr hdr;
56 Elf_Shdr *e_shdr;
57
58 int symtabindex; /* Index of symbol table */
59 int shstrindex; /* Index of section name string table */
60
61 int fd;
62 vm_offset_t off;
63 } *elf_file_t;
64
65 static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef,
66 u_int64_t loadaddr);
67 static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef,
68 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp);
69 static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef,
70 Elf_Addr p, void *val, size_t len);
71 static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp,
72 elf_file_t ef);
73 static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx);
74
75 const char *__elfN(obj_kerneltype) = "elf kernel";
76 const char *__elfN(obj_moduletype) = "elf obj module";
77
78 /*
79 * Attempt to load the file (file) as an ELF module. It will be stored at
80 * (dest), and a pointer to a module structure describing the loaded object
81 * will be saved in (result).
82 */
83 int
__elfN(obj_loadfile)84 __elfN(obj_loadfile)(char *filename, u_int64_t dest,
85 struct preloaded_file **result)
86 {
87 struct preloaded_file *fp, *kfp;
88 struct elf_file ef;
89 Elf_Ehdr *hdr;
90 int err;
91 ssize_t bytes_read;
92
93 fp = NULL;
94 bzero(&ef, sizeof(struct elf_file));
95
96 /*
97 * Open the image, read and validate the ELF header
98 */
99 if (filename == NULL) /* can't handle nameless */
100 return(EFTYPE);
101 if ((ef.fd = open(filename, O_RDONLY)) == -1)
102 return(errno);
103
104 hdr = &ef.hdr;
105 bytes_read = read(ef.fd, hdr, sizeof(*hdr));
106 if (bytes_read != sizeof(*hdr)) {
107 err = EFTYPE; /* could be EIO, but may be small file */
108 goto oerr;
109 }
110
111 /* Is it ELF? */
112 if (!IS_ELF(*hdr)) {
113 err = EFTYPE;
114 goto oerr;
115 }
116 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */
117 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
118 hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */
119 hdr->e_version != EV_CURRENT ||
120 hdr->e_machine != ELF_TARG_MACH || /* Machine ? */
121 hdr->e_type != ET_REL) {
122 err = EFTYPE;
123 goto oerr;
124 }
125
126 if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 ||
127 hdr->e_shentsize != sizeof(Elf_Shdr)) {
128 err = EFTYPE;
129 goto oerr;
130 }
131
132 kfp = file_findfile(NULL, __elfN(obj_kerneltype));
133 if (kfp == NULL) {
134 printf("elf" __XSTRING(__ELF_WORD_SIZE)
135 "_obj_loadfile: can't load module before kernel\n");
136 err = EPERM;
137 goto oerr;
138 }
139
140 if (archsw.arch_loadaddr != NULL)
141 dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest);
142 else
143 dest = roundup(dest, PAGE_SIZE);
144
145 /*
146 * Ok, we think we should handle this.
147 */
148 fp = file_alloc();
149 if (fp == NULL) {
150 printf("elf" __XSTRING(__ELF_WORD_SIZE)
151 "_obj_loadfile: cannot allocate module info\n");
152 err = EPERM;
153 goto out;
154 }
155 fp->f_name = strdup(filename);
156 fp->f_type = strdup(__elfN(obj_moduletype));
157
158 printf("%s ", filename);
159
160 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest);
161 if (fp->f_size == 0 || fp->f_addr == 0)
162 goto ioerr;
163
164 /* save exec header as metadata */
165 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr);
166
167 /* Load OK, return module pointer */
168 *result = (struct preloaded_file *)fp;
169 err = 0;
170 goto out;
171
172 ioerr:
173 err = EIO;
174 oerr:
175 file_discard(fp);
176 out:
177 close(ef.fd);
178 if (ef.e_shdr != NULL)
179 free(ef.e_shdr);
180
181 return(err);
182 }
183
184 /*
185 * With the file (fd) open on the image, and (ehdr) containing
186 * the Elf header, load the image at (off)
187 */
188 static int
__elfN(obj_loadimage)189 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
190 {
191 Elf_Ehdr *hdr;
192 Elf_Shdr *shdr, *cshdr, *lshdr;
193 vm_offset_t firstaddr, lastaddr;
194 int i, nsym, res, ret, shdrbytes, symstrindex;
195
196 ret = 0;
197 firstaddr = lastaddr = (vm_offset_t)off;
198 hdr = &ef->hdr;
199 ef->off = (vm_offset_t)off;
200
201 /* Read in the section headers. */
202 shdrbytes = hdr->e_shnum * hdr->e_shentsize;
203 shdr = alloc_pread(ef->fd, (off_t)hdr->e_shoff, shdrbytes);
204 if (shdr == NULL) {
205 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
206 "_obj_loadimage: read section headers failed\n");
207 goto out;
208 }
209 ef->e_shdr = shdr;
210
211 /*
212 * Decide where to load everything, but don't read it yet.
213 * We store the load address as a non-zero sh_addr value.
214 * Start with the code/data and bss.
215 */
216 for (i = 0; i < hdr->e_shnum; i++)
217 shdr[i].sh_addr = 0;
218 for (i = 0; i < hdr->e_shnum; i++) {
219 if (shdr[i].sh_size == 0)
220 continue;
221 switch (shdr[i].sh_type) {
222 case SHT_PROGBITS:
223 case SHT_NOBITS:
224 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
225 shdr[i].sh_addr = (Elf_Addr)lastaddr;
226 lastaddr += shdr[i].sh_size;
227 break;
228 }
229 }
230
231 /* Symbols. */
232 nsym = 0;
233 for (i = 0; i < hdr->e_shnum; i++) {
234 switch (shdr[i].sh_type) {
235 case SHT_SYMTAB:
236 nsym++;
237 ef->symtabindex = i;
238 shdr[i].sh_addr = (Elf_Addr)lastaddr;
239 lastaddr += shdr[i].sh_size;
240 break;
241 }
242 }
243 if (nsym != 1) {
244 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
245 "_obj_loadimage: file has no valid symbol table\n");
246 goto out;
247 }
248 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign);
249 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr;
250 lastaddr += shdr[ef->symtabindex].sh_size;
251
252 symstrindex = shdr[ef->symtabindex].sh_link;
253 if (symstrindex < 0 || symstrindex >= hdr->e_shnum ||
254 shdr[symstrindex].sh_type != SHT_STRTAB) {
255 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
256 "_obj_loadimage: file has invalid symbol strings\n");
257 goto out;
258 }
259 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign);
260 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr;
261 lastaddr += shdr[symstrindex].sh_size;
262
263 /* Section names. */
264 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum ||
265 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
266 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
267 "_obj_loadimage: file has no section names\n");
268 goto out;
269 }
270 ef->shstrindex = hdr->e_shstrndx;
271 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign);
272 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr;
273 lastaddr += shdr[ef->shstrindex].sh_size;
274
275 /* Relocation tables. */
276 for (i = 0; i < hdr->e_shnum; i++) {
277 switch (shdr[i].sh_type) {
278 case SHT_REL:
279 case SHT_RELA:
280 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
281 shdr[i].sh_addr = (Elf_Addr)lastaddr;
282 lastaddr += shdr[i].sh_size;
283 break;
284 }
285 }
286
287 /* Clear the whole area, including bss regions. */
288 kern_bzero(firstaddr, lastaddr - firstaddr);
289
290 /* Figure section with the lowest file offset we haven't loaded yet. */
291 for (cshdr = NULL; /* none */; /* none */)
292 {
293 /*
294 * Find next section to load. The complexity of this loop is
295 * O(n^2), but with the number of sections being typically
296 * small, we do not care.
297 */
298 lshdr = cshdr;
299
300 for (i = 0; i < hdr->e_shnum; i++) {
301 if (shdr[i].sh_addr == 0 ||
302 shdr[i].sh_type == SHT_NOBITS)
303 continue;
304 /* Skip sections that were loaded already. */
305 if (lshdr != NULL &&
306 lshdr->sh_offset >= shdr[i].sh_offset)
307 continue;
308 /* Find section with smallest offset. */
309 if (cshdr == lshdr ||
310 cshdr->sh_offset > shdr[i].sh_offset)
311 cshdr = &shdr[i];
312 }
313
314 if (cshdr == lshdr)
315 break;
316
317 if (kern_pread(ef->fd, (vm_offset_t)cshdr->sh_addr,
318 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) {
319 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
320 "_obj_loadimage: read failed\n");
321 goto out;
322 }
323 }
324
325 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr);
326
327 res = __elfN(obj_parse_modmetadata)(fp, ef);
328 if (res != 0)
329 goto out;
330
331 ret = lastaddr - firstaddr;
332 fp->f_addr = firstaddr;
333
334 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr);
335
336 out:
337 printf("\n");
338 return ret;
339 }
340
341 #if defined(__i386__) && __ELF_WORD_SIZE == 64
342 struct mod_metadata64 {
343 int md_version; /* structure version MDTV_* */
344 int md_type; /* type of entry MDT_* */
345 u_int64_t md_data; /* specific data */
346 u_int64_t md_cval; /* common string label */
347 };
348 #endif
349
350 int
__elfN(obj_parse_modmetadata)351 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
352 {
353 struct mod_metadata md;
354 #if defined(__i386__) && __ELF_WORD_SIZE == 64
355 struct mod_metadata64 md64;
356 #endif
357 struct mod_depend *mdepend;
358 struct mod_version mver;
359 char *s;
360 int error, modcnt, minfolen;
361 Elf_Addr v, p, p_stop;
362
363 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop,
364 &modcnt) != 0)
365 return 0;
366
367 modcnt = 0;
368 while (p < p_stop) {
369 COPYOUT(p, &v, sizeof(v));
370 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v));
371 if (error != 0)
372 return (error);
373 #if defined(__i386__) && __ELF_WORD_SIZE == 64
374 COPYOUT(v, &md64, sizeof(md64));
375 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64));
376 if (error != 0)
377 return (error);
378 md.md_version = md64.md_version;
379 md.md_type = md64.md_type;
380 md.md_cval = (const char *)(uintptr_t)md64.md_cval;
381 md.md_data = (void *)(uintptr_t)md64.md_data;
382 #else
383 COPYOUT(v, &md, sizeof(md));
384 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md));
385 if (error != 0)
386 return (error);
387 #endif
388 p += sizeof(Elf_Addr);
389 switch(md.md_type) {
390 case MDT_DEPEND:
391 s = strdupout((vm_offset_t)md.md_cval);
392 minfolen = sizeof(*mdepend) + strlen(s) + 1;
393 mdepend = malloc(minfolen);
394 if (mdepend == NULL)
395 return ENOMEM;
396 COPYOUT((vm_offset_t)md.md_data, mdepend,
397 sizeof(*mdepend));
398 strcpy((char*)(mdepend + 1), s);
399 free(s);
400 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen,
401 mdepend);
402 free(mdepend);
403 break;
404 case MDT_VERSION:
405 s = strdupout((vm_offset_t)md.md_cval);
406 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver));
407 file_addmodule(fp, s, mver.mv_version, NULL);
408 free(s);
409 modcnt++;
410 break;
411 case MDT_MODULE:
412 case MDT_PNP_INFO:
413 break;
414 default:
415 printf("unknown type %d\n", md.md_type);
416 break;
417 }
418 }
419 return 0;
420 }
421
422 static int
__elfN(obj_lookup_set)423 __elfN(obj_lookup_set)(struct preloaded_file *fp __unused, elf_file_t ef,
424 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp)
425 {
426 Elf_Ehdr *hdr;
427 Elf_Shdr *shdr;
428 char *p;
429 vm_offset_t shstrtab;
430 int i;
431
432 hdr = &ef->hdr;
433 shdr = ef->e_shdr;
434 shstrtab = shdr[ef->shstrindex].sh_addr;
435
436 for (i = 0; i < hdr->e_shnum; i++) {
437 if (shdr[i].sh_type != SHT_PROGBITS)
438 continue;
439 if (shdr[i].sh_name == 0)
440 continue;
441 p = strdupout(shstrtab + shdr[i].sh_name);
442 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) {
443 *startp = shdr[i].sh_addr;
444 *stopp = shdr[i].sh_addr + shdr[i].sh_size;
445 *countp = (*stopp - *startp) / sizeof(Elf_Addr);
446 free(p);
447 return (0);
448 }
449 free(p);
450 }
451
452 return (ESRCH);
453 }
454
455 /*
456 * Apply any intra-module relocations to the value. p is the load address
457 * of the value and val/len is the value to be modified. This does NOT modify
458 * the image in-place, because this is done by kern_linker later on.
459 */
460 static int
__elfN(obj_reloc_ptr)461 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p,
462 void *val, size_t len)
463 {
464 Elf_Ehdr *hdr;
465 Elf_Shdr *shdr;
466 Elf_Addr off = p;
467 Elf_Addr base;
468 Elf_Rela a, *abase;
469 Elf_Rel r, *rbase;
470 int error, i, j, nrel, nrela;
471
472 (void)mp;
473 hdr = &ef->hdr;
474 shdr = ef->e_shdr;
475
476 for (i = 0; i < hdr->e_shnum; i++) {
477 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL)
478 continue;
479 base = shdr[shdr[i].sh_info].sh_addr;
480 if (base == 0 || shdr[i].sh_addr == 0)
481 continue;
482 if (off < base || off + len > base +
483 shdr[shdr[i].sh_info].sh_size)
484 continue;
485
486 switch (shdr[i].sh_type) {
487 case SHT_RELA:
488 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr;
489
490 nrela = shdr[i].sh_size / sizeof(Elf_Rela);
491 for (j = 0; j < nrela; j++) {
492 COPYOUT(abase + j, &a, sizeof(a));
493
494 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
495 &a, ELF_RELOC_RELA, base, off, val, len);
496 if (error != 0)
497 return (error);
498 }
499 break;
500 case SHT_REL:
501 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr;
502
503 nrel = shdr[i].sh_size / sizeof(Elf_Rel);
504 for (j = 0; j < nrel; j++) {
505 COPYOUT(rbase + j, &r, sizeof(r));
506
507 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
508 &r, ELF_RELOC_REL, base, off, val, len);
509 if (error != 0)
510 return (error);
511 }
512 break;
513 }
514 }
515 return (0);
516 }
517
518 /* Look up the address of a specified symbol. */
519 static Elf_Addr
__elfN(obj_symaddr)520 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx)
521 {
522 Elf_Sym sym;
523 Elf_Addr base;
524
525 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym))
526 return (0);
527 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym),
528 &sym, sizeof(sym));
529 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum)
530 return (0);
531 base = ef->e_shdr[sym.st_shndx].sh_addr;
532 if (base == 0)
533 return (0);
534 return (base + sym.st_value);
535 }
536