1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1998-2000 Doug Rabson
5 * Copyright (c) 2004 Peter Wemm
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32
33 #include "opt_ddb.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/mount.h>
42 #include <sys/proc.h>
43 #include <sys/namei.h>
44 #include <sys/fcntl.h>
45 #include <sys/vnode.h>
46 #include <sys/linker.h>
47
48 #include <machine/elf.h>
49
50 #include <net/vnet.h>
51
52 #include <security/mac/mac_framework.h>
53
54 #include <vm/vm.h>
55 #include <vm/vm_param.h>
56 #include <vm/vm_object.h>
57 #include <vm/vm_kern.h>
58 #include <vm/vm_extern.h>
59 #include <vm/pmap.h>
60 #include <vm/vm_map.h>
61
62 #include <sys/link_elf.h>
63
64 #ifdef DDB_CTF
65 #include <sys/zlib.h>
66 #endif
67
68 #include "linker_if.h"
69
70 typedef struct {
71 void *addr;
72 Elf_Off size;
73 int flags;
74 int sec; /* Original section */
75 char *name;
76 } Elf_progent;
77
78 typedef struct {
79 Elf_Rel *rel;
80 int nrel;
81 int sec;
82 } Elf_relent;
83
84 typedef struct {
85 Elf_Rela *rela;
86 int nrela;
87 int sec;
88 } Elf_relaent;
89
90
91 typedef struct elf_file {
92 struct linker_file lf; /* Common fields */
93
94 int preloaded;
95 caddr_t address; /* Relocation address */
96 vm_object_t object; /* VM object to hold file pages */
97 Elf_Shdr *e_shdr;
98
99 Elf_progent *progtab;
100 u_int nprogtab;
101
102 Elf_relaent *relatab;
103 u_int nrelatab;
104
105 Elf_relent *reltab;
106 int nreltab;
107
108 Elf_Sym *ddbsymtab; /* The symbol table we are using */
109 long ddbsymcnt; /* Number of symbols */
110 caddr_t ddbstrtab; /* String table */
111 long ddbstrcnt; /* number of bytes in string table */
112
113 caddr_t shstrtab; /* Section name string table */
114 long shstrcnt; /* number of bytes in string table */
115
116 caddr_t ctftab; /* CTF table */
117 long ctfcnt; /* number of bytes in CTF table */
118 caddr_t ctfoff; /* CTF offset table */
119 caddr_t typoff; /* Type offset table */
120 long typlen; /* Number of type entries. */
121
122 } *elf_file_t;
123
124 #include <kern/kern_ctf.c>
125
126 static int link_elf_link_preload(linker_class_t cls,
127 const char *, linker_file_t *);
128 static int link_elf_link_preload_finish(linker_file_t);
129 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *);
130 static int link_elf_lookup_symbol(linker_file_t, const char *,
131 c_linker_sym_t *);
132 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
133 linker_symval_t *);
134 static int link_elf_search_symbol(linker_file_t, caddr_t value,
135 c_linker_sym_t *sym, long *diffp);
136
137 static void link_elf_unload_file(linker_file_t);
138 static int link_elf_lookup_set(linker_file_t, const char *,
139 void ***, void ***, int *);
140 static int link_elf_each_function_name(linker_file_t,
141 int (*)(const char *, void *), void *);
142 static int link_elf_each_function_nameval(linker_file_t,
143 linker_function_nameval_callback_t,
144 void *);
145 static int link_elf_reloc_local(linker_file_t, bool);
146 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
147 static long link_elf_strtab_get(linker_file_t, caddr_t *);
148
149 static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
150 Elf_Addr *);
151
152 static kobj_method_t link_elf_methods[] = {
153 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
154 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
155 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
156 KOBJMETHOD(linker_unload, link_elf_unload_file),
157 KOBJMETHOD(linker_load_file, link_elf_load_file),
158 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
159 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
160 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
161 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
162 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
163 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
164 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
165 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
166 { 0, 0 }
167 };
168
169 static struct linker_class link_elf_class = {
170 #if ELF_TARG_CLASS == ELFCLASS32
171 "elf32_obj",
172 #else
173 "elf64_obj",
174 #endif
175 link_elf_methods, sizeof(struct elf_file)
176 };
177
178 static int relocate_file(elf_file_t ef);
179 static void elf_obj_cleanup_globals_cache(elf_file_t);
180
181 static void
link_elf_error(const char * filename,const char * s)182 link_elf_error(const char *filename, const char *s)
183 {
184 if (filename == NULL)
185 printf("kldload: %s\n", s);
186 else
187 printf("kldload: %s: %s\n", filename, s);
188 }
189
190 static void
link_elf_init(void * arg)191 link_elf_init(void *arg)
192 {
193
194 linker_add_class(&link_elf_class);
195 }
196
197 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL);
198
199 static int
link_elf_link_preload(linker_class_t cls,const char * filename,linker_file_t * result)200 link_elf_link_preload(linker_class_t cls, const char *filename,
201 linker_file_t *result)
202 {
203 Elf_Ehdr *hdr;
204 Elf_Shdr *shdr;
205 Elf_Sym *es;
206 void *modptr, *baseptr, *sizeptr;
207 char *type;
208 elf_file_t ef;
209 linker_file_t lf;
210 Elf_Addr off;
211 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
212
213 /* Look to see if we have the file preloaded */
214 modptr = preload_search_by_name(filename);
215 if (modptr == NULL)
216 return ENOENT;
217
218 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
219 baseptr = preload_search_info(modptr, MODINFO_ADDR);
220 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
221 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
222 MODINFOMD_ELFHDR);
223 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
224 MODINFOMD_SHDR);
225 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
226 " obj module") != 0 &&
227 strcmp(type, "elf obj module") != 0)) {
228 return (EFTYPE);
229 }
230 if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
231 shdr == NULL)
232 return (EINVAL);
233
234 lf = linker_make_file(filename, &link_elf_class);
235 if (lf == NULL)
236 return (ENOMEM);
237
238 ef = (elf_file_t)lf;
239 ef->preloaded = 1;
240 ef->address = *(caddr_t *)baseptr;
241 lf->address = *(caddr_t *)baseptr;
242 lf->size = *(size_t *)sizeptr;
243
244 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
245 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
246 hdr->e_ident[EI_VERSION] != EV_CURRENT ||
247 hdr->e_version != EV_CURRENT ||
248 hdr->e_type != ET_REL ||
249 hdr->e_machine != ELF_TARG_MACH) {
250 error = EFTYPE;
251 goto out;
252 }
253 ef->e_shdr = shdr;
254
255 /* Scan the section header for information and table sizing. */
256 symtabindex = -1;
257 symstrindex = -1;
258 for (i = 0; i < hdr->e_shnum; i++) {
259 switch (shdr[i].sh_type) {
260 case SHT_PROGBITS:
261 case SHT_NOBITS:
262 #ifdef __amd64__
263 case SHT_X86_64_UNWIND:
264 #endif
265 /* Ignore sections not loaded by the loader. */
266 if (shdr[i].sh_addr == 0)
267 break;
268 ef->nprogtab++;
269 break;
270 case SHT_SYMTAB:
271 symtabindex = i;
272 symstrindex = shdr[i].sh_link;
273 break;
274 case SHT_REL:
275 /*
276 * Ignore relocation tables for sections not
277 * loaded by the loader.
278 */
279 if (shdr[shdr[i].sh_info].sh_addr == 0)
280 break;
281 ef->nreltab++;
282 break;
283 case SHT_RELA:
284 if (shdr[shdr[i].sh_info].sh_addr == 0)
285 break;
286 ef->nrelatab++;
287 break;
288 }
289 }
290
291 shstrindex = hdr->e_shstrndx;
292 if (ef->nprogtab == 0 || symstrindex < 0 ||
293 symstrindex >= hdr->e_shnum ||
294 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
295 shstrindex >= hdr->e_shnum ||
296 shdr[shstrindex].sh_type != SHT_STRTAB) {
297 printf("%s: bad/missing section headers\n", filename);
298 error = ENOEXEC;
299 goto out;
300 }
301
302 /* Allocate space for tracking the load chunks */
303 if (ef->nprogtab != 0)
304 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
305 M_LINKER, M_WAITOK | M_ZERO);
306 if (ef->nreltab != 0)
307 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
308 M_LINKER, M_WAITOK | M_ZERO);
309 if (ef->nrelatab != 0)
310 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
311 M_LINKER, M_WAITOK | M_ZERO);
312 if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
313 (ef->nreltab != 0 && ef->reltab == NULL) ||
314 (ef->nrelatab != 0 && ef->relatab == NULL)) {
315 error = ENOMEM;
316 goto out;
317 }
318
319 /* XXX, relocate the sh_addr fields saved by the loader. */
320 off = 0;
321 for (i = 0; i < hdr->e_shnum; i++) {
322 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
323 off = shdr[i].sh_addr;
324 }
325 for (i = 0; i < hdr->e_shnum; i++) {
326 if (shdr[i].sh_addr != 0)
327 shdr[i].sh_addr = shdr[i].sh_addr - off +
328 (Elf_Addr)ef->address;
329 }
330
331 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
332 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
333 ef->ddbstrcnt = shdr[symstrindex].sh_size;
334 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
335 ef->shstrcnt = shdr[shstrindex].sh_size;
336 ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
337
338 /* Now fill out progtab and the relocation tables. */
339 pb = 0;
340 rl = 0;
341 ra = 0;
342 for (i = 0; i < hdr->e_shnum; i++) {
343 switch (shdr[i].sh_type) {
344 case SHT_PROGBITS:
345 case SHT_NOBITS:
346 #ifdef __amd64__
347 case SHT_X86_64_UNWIND:
348 #endif
349 if (shdr[i].sh_addr == 0)
350 break;
351 ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
352 if (shdr[i].sh_type == SHT_PROGBITS)
353 ef->progtab[pb].name = "<<PROGBITS>>";
354 #ifdef __amd64__
355 else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
356 ef->progtab[pb].name = "<<UNWIND>>";
357 #endif
358 else
359 ef->progtab[pb].name = "<<NOBITS>>";
360 ef->progtab[pb].size = shdr[i].sh_size;
361 ef->progtab[pb].sec = i;
362 if (ef->shstrtab && shdr[i].sh_name != 0)
363 ef->progtab[pb].name =
364 ef->shstrtab + shdr[i].sh_name;
365 if (ef->progtab[pb].name != NULL &&
366 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
367 void *dpcpu;
368
369 dpcpu = dpcpu_alloc(shdr[i].sh_size);
370 if (dpcpu == NULL) {
371 printf("%s: pcpu module space is out "
372 "of space; cannot allocate %#jx "
373 "for %s\n", __func__,
374 (uintmax_t)shdr[i].sh_size,
375 filename);
376 error = ENOSPC;
377 goto out;
378 }
379 memcpy(dpcpu, ef->progtab[pb].addr,
380 ef->progtab[pb].size);
381 dpcpu_copy(dpcpu, shdr[i].sh_size);
382 ef->progtab[pb].addr = dpcpu;
383 #ifdef VIMAGE
384 } else if (ef->progtab[pb].name != NULL &&
385 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
386 void *vnet_data;
387
388 vnet_data = vnet_data_alloc(shdr[i].sh_size);
389 if (vnet_data == NULL) {
390 printf("%s: vnet module space is out "
391 "of space; cannot allocate %#jx "
392 "for %s\n", __func__,
393 (uintmax_t)shdr[i].sh_size,
394 filename);
395 error = ENOSPC;
396 goto out;
397 }
398 memcpy(vnet_data, ef->progtab[pb].addr,
399 ef->progtab[pb].size);
400 vnet_data_copy(vnet_data, shdr[i].sh_size);
401 ef->progtab[pb].addr = vnet_data;
402 #endif
403 } else if (ef->progtab[pb].name != NULL &&
404 !strcmp(ef->progtab[pb].name, ".ctors")) {
405 lf->ctors_addr = ef->progtab[pb].addr;
406 lf->ctors_size = shdr[i].sh_size;
407 }
408
409 /* Update all symbol values with the offset. */
410 for (j = 0; j < ef->ddbsymcnt; j++) {
411 es = &ef->ddbsymtab[j];
412 if (es->st_shndx != i)
413 continue;
414 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
415 }
416 pb++;
417 break;
418 case SHT_REL:
419 if (shdr[shdr[i].sh_info].sh_addr == 0)
420 break;
421 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
422 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
423 ef->reltab[rl].sec = shdr[i].sh_info;
424 rl++;
425 break;
426 case SHT_RELA:
427 if (shdr[shdr[i].sh_info].sh_addr == 0)
428 break;
429 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
430 ef->relatab[ra].nrela =
431 shdr[i].sh_size / sizeof(Elf_Rela);
432 ef->relatab[ra].sec = shdr[i].sh_info;
433 ra++;
434 break;
435 }
436 }
437 if (pb != ef->nprogtab) {
438 printf("%s: lost progbits\n", filename);
439 error = ENOEXEC;
440 goto out;
441 }
442 if (rl != ef->nreltab) {
443 printf("%s: lost reltab\n", filename);
444 error = ENOEXEC;
445 goto out;
446 }
447 if (ra != ef->nrelatab) {
448 printf("%s: lost relatab\n", filename);
449 error = ENOEXEC;
450 goto out;
451 }
452
453 /* Local intra-module relocations */
454 error = link_elf_reloc_local(lf, false);
455 if (error != 0)
456 goto out;
457 *result = lf;
458 return (0);
459
460 out:
461 /* preload not done this way */
462 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
463 return (error);
464 }
465
466 static void
link_elf_invoke_ctors(caddr_t addr,size_t size)467 link_elf_invoke_ctors(caddr_t addr, size_t size)
468 {
469 void (**ctor)(void);
470 size_t i, cnt;
471
472 if (addr == NULL || size == 0)
473 return;
474 cnt = size / sizeof(*ctor);
475 ctor = (void *)addr;
476 for (i = 0; i < cnt; i++) {
477 if (ctor[i] != NULL)
478 (*ctor[i])();
479 }
480 }
481
482 static int
link_elf_link_preload_finish(linker_file_t lf)483 link_elf_link_preload_finish(linker_file_t lf)
484 {
485 elf_file_t ef;
486 int error;
487
488 ef = (elf_file_t)lf;
489 error = relocate_file(ef);
490 if (error)
491 return (error);
492
493 /* Notify MD code that a module is being loaded. */
494 error = elf_cpu_load_file(lf);
495 if (error)
496 return (error);
497
498 #if defined(__i386__) || defined(__amd64__)
499 /* Now ifuncs. */
500 error = link_elf_reloc_local(lf, true);
501 if (error != 0)
502 return (error);
503 #endif
504
505 /* Invoke .ctors */
506 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
507 return (0);
508 }
509
510 static int
link_elf_load_file(linker_class_t cls,const char * filename,linker_file_t * result)511 link_elf_load_file(linker_class_t cls, const char *filename,
512 linker_file_t *result)
513 {
514 struct nameidata *nd;
515 struct thread *td = curthread; /* XXX */
516 Elf_Ehdr *hdr;
517 Elf_Shdr *shdr;
518 Elf_Sym *es;
519 int nbytes, i, j;
520 vm_offset_t mapbase;
521 size_t mapsize;
522 int error = 0;
523 ssize_t resid;
524 int flags;
525 elf_file_t ef;
526 linker_file_t lf;
527 int symtabindex;
528 int symstrindex;
529 int shstrindex;
530 int nsym;
531 int pb, rl, ra;
532 int alignmask;
533
534 shdr = NULL;
535 lf = NULL;
536 mapsize = 0;
537 hdr = NULL;
538
539 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
540 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
541 flags = FREAD;
542 error = vn_open(nd, &flags, 0, NULL);
543 if (error) {
544 free(nd, M_TEMP);
545 return error;
546 }
547 NDFREE(nd, NDF_ONLY_PNBUF);
548 if (nd->ni_vp->v_type != VREG) {
549 error = ENOEXEC;
550 goto out;
551 }
552 #ifdef MAC
553 error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
554 if (error) {
555 goto out;
556 }
557 #endif
558
559 /* Read the elf header from the file. */
560 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
561 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
562 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
563 &resid, td);
564 if (error)
565 goto out;
566 if (resid != 0){
567 error = ENOEXEC;
568 goto out;
569 }
570
571 if (!IS_ELF(*hdr)) {
572 error = ENOEXEC;
573 goto out;
574 }
575
576 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
577 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
578 link_elf_error(filename, "Unsupported file layout");
579 error = ENOEXEC;
580 goto out;
581 }
582 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
583 || hdr->e_version != EV_CURRENT) {
584 link_elf_error(filename, "Unsupported file version");
585 error = ENOEXEC;
586 goto out;
587 }
588 if (hdr->e_type != ET_REL) {
589 error = ENOSYS;
590 goto out;
591 }
592 if (hdr->e_machine != ELF_TARG_MACH) {
593 link_elf_error(filename, "Unsupported machine");
594 error = ENOEXEC;
595 goto out;
596 }
597
598 lf = linker_make_file(filename, &link_elf_class);
599 if (!lf) {
600 error = ENOMEM;
601 goto out;
602 }
603 ef = (elf_file_t) lf;
604 ef->nprogtab = 0;
605 ef->e_shdr = 0;
606 ef->nreltab = 0;
607 ef->nrelatab = 0;
608
609 /* Allocate and read in the section header */
610 nbytes = hdr->e_shnum * hdr->e_shentsize;
611 if (nbytes == 0 || hdr->e_shoff == 0 ||
612 hdr->e_shentsize != sizeof(Elf_Shdr)) {
613 error = ENOEXEC;
614 goto out;
615 }
616 shdr = malloc(nbytes, M_LINKER, M_WAITOK);
617 ef->e_shdr = shdr;
618 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
619 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
620 NOCRED, &resid, td);
621 if (error)
622 goto out;
623 if (resid) {
624 error = ENOEXEC;
625 goto out;
626 }
627
628 /* Scan the section header for information and table sizing. */
629 nsym = 0;
630 symtabindex = -1;
631 symstrindex = -1;
632 for (i = 0; i < hdr->e_shnum; i++) {
633 if (shdr[i].sh_size == 0)
634 continue;
635 switch (shdr[i].sh_type) {
636 case SHT_PROGBITS:
637 case SHT_NOBITS:
638 #ifdef __amd64__
639 case SHT_X86_64_UNWIND:
640 #endif
641 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
642 break;
643 ef->nprogtab++;
644 break;
645 case SHT_SYMTAB:
646 nsym++;
647 symtabindex = i;
648 symstrindex = shdr[i].sh_link;
649 break;
650 case SHT_REL:
651 /*
652 * Ignore relocation tables for unallocated
653 * sections.
654 */
655 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
656 break;
657 ef->nreltab++;
658 break;
659 case SHT_RELA:
660 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
661 break;
662 ef->nrelatab++;
663 break;
664 case SHT_STRTAB:
665 break;
666 }
667 }
668 if (ef->nprogtab == 0) {
669 link_elf_error(filename, "file has no contents");
670 error = ENOEXEC;
671 goto out;
672 }
673 if (nsym != 1) {
674 /* Only allow one symbol table for now */
675 link_elf_error(filename,
676 "file must have exactly one symbol table");
677 error = ENOEXEC;
678 goto out;
679 }
680 if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
681 shdr[symstrindex].sh_type != SHT_STRTAB) {
682 link_elf_error(filename, "file has invalid symbol strings");
683 error = ENOEXEC;
684 goto out;
685 }
686
687 /* Allocate space for tracking the load chunks */
688 if (ef->nprogtab != 0)
689 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
690 M_LINKER, M_WAITOK | M_ZERO);
691 if (ef->nreltab != 0)
692 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
693 M_LINKER, M_WAITOK | M_ZERO);
694 if (ef->nrelatab != 0)
695 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
696 M_LINKER, M_WAITOK | M_ZERO);
697
698 if (symtabindex == -1) {
699 link_elf_error(filename, "lost symbol table index");
700 error = ENOEXEC;
701 goto out;
702 }
703 /* Allocate space for and load the symbol table */
704 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
705 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
706 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
707 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
708 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
709 &resid, td);
710 if (error)
711 goto out;
712 if (resid != 0){
713 error = EINVAL;
714 goto out;
715 }
716
717 /* Allocate space for and load the symbol strings */
718 ef->ddbstrcnt = shdr[symstrindex].sh_size;
719 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
720 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
721 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
722 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
723 &resid, td);
724 if (error)
725 goto out;
726 if (resid != 0){
727 error = EINVAL;
728 goto out;
729 }
730
731 /* Do we have a string table for the section names? */
732 shstrindex = -1;
733 if (hdr->e_shstrndx != 0 &&
734 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
735 shstrindex = hdr->e_shstrndx;
736 ef->shstrcnt = shdr[shstrindex].sh_size;
737 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
738 M_WAITOK);
739 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
740 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
741 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
742 &resid, td);
743 if (error)
744 goto out;
745 if (resid != 0){
746 error = EINVAL;
747 goto out;
748 }
749 }
750
751 /* Size up code/data(progbits) and bss(nobits). */
752 alignmask = 0;
753 for (i = 0; i < hdr->e_shnum; i++) {
754 if (shdr[i].sh_size == 0)
755 continue;
756 switch (shdr[i].sh_type) {
757 case SHT_PROGBITS:
758 case SHT_NOBITS:
759 #ifdef __amd64__
760 case SHT_X86_64_UNWIND:
761 #endif
762 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
763 break;
764 alignmask = shdr[i].sh_addralign - 1;
765 mapsize += alignmask;
766 mapsize &= ~alignmask;
767 mapsize += shdr[i].sh_size;
768 break;
769 }
770 }
771
772 /*
773 * We know how much space we need for the text/data/bss/etc.
774 * This stuff needs to be in a single chunk so that profiling etc
775 * can get the bounds and gdb can associate offsets with modules
776 */
777 ef->object = vm_object_allocate(OBJT_DEFAULT,
778 round_page(mapsize) >> PAGE_SHIFT);
779 if (ef->object == NULL) {
780 error = ENOMEM;
781 goto out;
782 }
783 ef->address = (caddr_t) vm_map_min(kernel_map);
784
785 /*
786 * In order to satisfy amd64's architectural requirements on the
787 * location of code and data in the kernel's address space, request a
788 * mapping that is above the kernel.
789 */
790 #ifdef __amd64__
791 mapbase = KERNBASE;
792 #else
793 mapbase = VM_MIN_KERNEL_ADDRESS;
794 #endif
795 error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
796 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
797 VM_PROT_ALL, 0);
798 if (error) {
799 vm_object_deallocate(ef->object);
800 ef->object = 0;
801 goto out;
802 }
803
804 /* Wire the pages */
805 error = vm_map_wire(kernel_map, mapbase,
806 mapbase + round_page(mapsize),
807 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
808 if (error != KERN_SUCCESS) {
809 error = ENOMEM;
810 goto out;
811 }
812
813 /* Inform the kld system about the situation */
814 lf->address = ef->address = (caddr_t)mapbase;
815 lf->size = mapsize;
816
817 /*
818 * Now load code/data(progbits), zero bss(nobits), allocate space for
819 * and load relocs
820 */
821 pb = 0;
822 rl = 0;
823 ra = 0;
824 alignmask = 0;
825 for (i = 0; i < hdr->e_shnum; i++) {
826 if (shdr[i].sh_size == 0)
827 continue;
828 switch (shdr[i].sh_type) {
829 case SHT_PROGBITS:
830 case SHT_NOBITS:
831 #ifdef __amd64__
832 case SHT_X86_64_UNWIND:
833 #endif
834 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
835 break;
836 alignmask = shdr[i].sh_addralign - 1;
837 mapbase += alignmask;
838 mapbase &= ~alignmask;
839 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
840 ef->progtab[pb].name =
841 ef->shstrtab + shdr[i].sh_name;
842 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
843 lf->ctors_addr = (caddr_t)mapbase;
844 lf->ctors_size = shdr[i].sh_size;
845 }
846 } else if (shdr[i].sh_type == SHT_PROGBITS)
847 ef->progtab[pb].name = "<<PROGBITS>>";
848 #ifdef __amd64__
849 else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
850 ef->progtab[pb].name = "<<UNWIND>>";
851 #endif
852 else
853 ef->progtab[pb].name = "<<NOBITS>>";
854 if (ef->progtab[pb].name != NULL &&
855 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
856 ef->progtab[pb].addr =
857 dpcpu_alloc(shdr[i].sh_size);
858 if (ef->progtab[pb].addr == NULL) {
859 printf("%s: pcpu module space is out "
860 "of space; cannot allocate %#jx "
861 "for %s\n", __func__,
862 (uintmax_t)shdr[i].sh_size,
863 filename);
864 }
865 }
866 #ifdef VIMAGE
867 else if (ef->progtab[pb].name != NULL &&
868 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
869 ef->progtab[pb].addr =
870 vnet_data_alloc(shdr[i].sh_size);
871 if (ef->progtab[pb].addr == NULL) {
872 printf("%s: vnet module space is out "
873 "of space; cannot allocate %#jx "
874 "for %s\n", __func__,
875 (uintmax_t)shdr[i].sh_size,
876 filename);
877 }
878 }
879 #endif
880 else
881 ef->progtab[pb].addr =
882 (void *)(uintptr_t)mapbase;
883 if (ef->progtab[pb].addr == NULL) {
884 error = ENOSPC;
885 goto out;
886 }
887 ef->progtab[pb].size = shdr[i].sh_size;
888 ef->progtab[pb].sec = i;
889 if (shdr[i].sh_type == SHT_PROGBITS
890 #ifdef __amd64__
891 || shdr[i].sh_type == SHT_X86_64_UNWIND
892 #endif
893 ) {
894 error = vn_rdwr(UIO_READ, nd->ni_vp,
895 ef->progtab[pb].addr,
896 shdr[i].sh_size, shdr[i].sh_offset,
897 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
898 NOCRED, &resid, td);
899 if (error)
900 goto out;
901 if (resid != 0){
902 error = EINVAL;
903 goto out;
904 }
905 /* Initialize the per-cpu or vnet area. */
906 if (ef->progtab[pb].addr != (void *)mapbase &&
907 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
908 dpcpu_copy(ef->progtab[pb].addr,
909 shdr[i].sh_size);
910 #ifdef VIMAGE
911 else if (ef->progtab[pb].addr !=
912 (void *)mapbase &&
913 !strcmp(ef->progtab[pb].name, VNET_SETNAME))
914 vnet_data_copy(ef->progtab[pb].addr,
915 shdr[i].sh_size);
916 #endif
917 } else
918 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
919
920 /* Update all symbol values with the offset. */
921 for (j = 0; j < ef->ddbsymcnt; j++) {
922 es = &ef->ddbsymtab[j];
923 if (es->st_shndx != i)
924 continue;
925 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
926 }
927 mapbase += shdr[i].sh_size;
928 pb++;
929 break;
930 case SHT_REL:
931 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
932 break;
933 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
934 M_WAITOK);
935 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
936 ef->reltab[rl].sec = shdr[i].sh_info;
937 error = vn_rdwr(UIO_READ, nd->ni_vp,
938 (void *)ef->reltab[rl].rel,
939 shdr[i].sh_size, shdr[i].sh_offset,
940 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
941 &resid, td);
942 if (error)
943 goto out;
944 if (resid != 0){
945 error = EINVAL;
946 goto out;
947 }
948 rl++;
949 break;
950 case SHT_RELA:
951 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
952 break;
953 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
954 M_WAITOK);
955 ef->relatab[ra].nrela =
956 shdr[i].sh_size / sizeof(Elf_Rela);
957 ef->relatab[ra].sec = shdr[i].sh_info;
958 error = vn_rdwr(UIO_READ, nd->ni_vp,
959 (void *)ef->relatab[ra].rela,
960 shdr[i].sh_size, shdr[i].sh_offset,
961 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
962 &resid, td);
963 if (error)
964 goto out;
965 if (resid != 0){
966 error = EINVAL;
967 goto out;
968 }
969 ra++;
970 break;
971 }
972 }
973 if (pb != ef->nprogtab) {
974 link_elf_error(filename, "lost progbits");
975 error = ENOEXEC;
976 goto out;
977 }
978 if (rl != ef->nreltab) {
979 link_elf_error(filename, "lost reltab");
980 error = ENOEXEC;
981 goto out;
982 }
983 if (ra != ef->nrelatab) {
984 link_elf_error(filename, "lost relatab");
985 error = ENOEXEC;
986 goto out;
987 }
988 if (mapbase != (vm_offset_t)ef->address + mapsize) {
989 printf(
990 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
991 filename != NULL ? filename : "<none>",
992 (u_long)mapbase, ef->address, (u_long)mapsize,
993 (u_long)(vm_offset_t)ef->address + mapsize);
994 error = ENOMEM;
995 goto out;
996 }
997
998 /* Local intra-module relocations */
999 error = link_elf_reloc_local(lf, false);
1000 if (error != 0)
1001 goto out;
1002
1003 /* Pull in dependencies */
1004 VOP_UNLOCK(nd->ni_vp, 0);
1005 error = linker_load_dependencies(lf);
1006 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
1007 if (error)
1008 goto out;
1009
1010 /* External relocations */
1011 error = relocate_file(ef);
1012 if (error)
1013 goto out;
1014
1015 /* Notify MD code that a module is being loaded. */
1016 error = elf_cpu_load_file(lf);
1017 if (error)
1018 goto out;
1019
1020 #if defined(__i386__) || defined(__amd64__)
1021 /* Now ifuncs. */
1022 error = link_elf_reloc_local(lf, true);
1023 if (error != 0)
1024 goto out;
1025 #endif
1026
1027 /* Invoke .ctors */
1028 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
1029
1030 *result = lf;
1031
1032 out:
1033 VOP_UNLOCK(nd->ni_vp, 0);
1034 vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
1035 free(nd, M_TEMP);
1036 if (error && lf)
1037 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1038 free(hdr, M_LINKER);
1039
1040 return error;
1041 }
1042
1043 static void
link_elf_unload_file(linker_file_t file)1044 link_elf_unload_file(linker_file_t file)
1045 {
1046 elf_file_t ef = (elf_file_t) file;
1047 u_int i;
1048
1049 /* Notify MD code that a module is being unloaded. */
1050 elf_cpu_unload_file(file);
1051
1052 if (ef->progtab) {
1053 for (i = 0; i < ef->nprogtab; i++) {
1054 if (ef->progtab[i].size == 0)
1055 continue;
1056 if (ef->progtab[i].name == NULL)
1057 continue;
1058 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
1059 dpcpu_free(ef->progtab[i].addr,
1060 ef->progtab[i].size);
1061 #ifdef VIMAGE
1062 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
1063 vnet_data_free(ef->progtab[i].addr,
1064 ef->progtab[i].size);
1065 #endif
1066 }
1067 }
1068 if (ef->preloaded) {
1069 free(ef->reltab, M_LINKER);
1070 free(ef->relatab, M_LINKER);
1071 free(ef->progtab, M_LINKER);
1072 free(ef->ctftab, M_LINKER);
1073 free(ef->ctfoff, M_LINKER);
1074 free(ef->typoff, M_LINKER);
1075 if (file->pathname != NULL)
1076 preload_delete_name(file->pathname);
1077 return;
1078 }
1079
1080 for (i = 0; i < ef->nreltab; i++)
1081 free(ef->reltab[i].rel, M_LINKER);
1082 for (i = 0; i < ef->nrelatab; i++)
1083 free(ef->relatab[i].rela, M_LINKER);
1084 free(ef->reltab, M_LINKER);
1085 free(ef->relatab, M_LINKER);
1086 free(ef->progtab, M_LINKER);
1087
1088 if (ef->object) {
1089 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1090 (vm_offset_t) ef->address +
1091 (ef->object->size << PAGE_SHIFT));
1092 }
1093 free(ef->e_shdr, M_LINKER);
1094 free(ef->ddbsymtab, M_LINKER);
1095 free(ef->ddbstrtab, M_LINKER);
1096 free(ef->shstrtab, M_LINKER);
1097 free(ef->ctftab, M_LINKER);
1098 free(ef->ctfoff, M_LINKER);
1099 free(ef->typoff, M_LINKER);
1100 }
1101
1102 static const char *
symbol_name(elf_file_t ef,Elf_Size r_info)1103 symbol_name(elf_file_t ef, Elf_Size r_info)
1104 {
1105 const Elf_Sym *ref;
1106
1107 if (ELF_R_SYM(r_info)) {
1108 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1109 return ef->ddbstrtab + ref->st_name;
1110 } else
1111 return NULL;
1112 }
1113
1114 static Elf_Addr
findbase(elf_file_t ef,int sec)1115 findbase(elf_file_t ef, int sec)
1116 {
1117 int i;
1118 Elf_Addr base = 0;
1119
1120 for (i = 0; i < ef->nprogtab; i++) {
1121 if (sec == ef->progtab[i].sec) {
1122 base = (Elf_Addr)ef->progtab[i].addr;
1123 break;
1124 }
1125 }
1126 return base;
1127 }
1128
1129 static int
relocate_file(elf_file_t ef)1130 relocate_file(elf_file_t ef)
1131 {
1132 const Elf_Rel *rellim;
1133 const Elf_Rel *rel;
1134 const Elf_Rela *relalim;
1135 const Elf_Rela *rela;
1136 const char *symname;
1137 const Elf_Sym *sym;
1138 int i;
1139 Elf_Size symidx;
1140 Elf_Addr base;
1141
1142
1143 /* Perform relocations without addend if there are any: */
1144 for (i = 0; i < ef->nreltab; i++) {
1145 rel = ef->reltab[i].rel;
1146 if (rel == NULL) {
1147 link_elf_error(ef->lf.filename, "lost a reltab!");
1148 return (ENOEXEC);
1149 }
1150 rellim = rel + ef->reltab[i].nrel;
1151 base = findbase(ef, ef->reltab[i].sec);
1152 if (base == 0) {
1153 link_elf_error(ef->lf.filename, "lost base for reltab");
1154 return (ENOEXEC);
1155 }
1156 for ( ; rel < rellim; rel++) {
1157 symidx = ELF_R_SYM(rel->r_info);
1158 if (symidx >= ef->ddbsymcnt)
1159 continue;
1160 sym = ef->ddbsymtab + symidx;
1161 /* Local relocs are already done */
1162 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1163 continue;
1164 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1165 elf_obj_lookup)) {
1166 symname = symbol_name(ef, rel->r_info);
1167 printf("link_elf_obj: symbol %s undefined\n",
1168 symname);
1169 return (ENOENT);
1170 }
1171 }
1172 }
1173
1174 /* Perform relocations with addend if there are any: */
1175 for (i = 0; i < ef->nrelatab; i++) {
1176 rela = ef->relatab[i].rela;
1177 if (rela == NULL) {
1178 link_elf_error(ef->lf.filename, "lost a relatab!");
1179 return (ENOEXEC);
1180 }
1181 relalim = rela + ef->relatab[i].nrela;
1182 base = findbase(ef, ef->relatab[i].sec);
1183 if (base == 0) {
1184 link_elf_error(ef->lf.filename,
1185 "lost base for relatab");
1186 return (ENOEXEC);
1187 }
1188 for ( ; rela < relalim; rela++) {
1189 symidx = ELF_R_SYM(rela->r_info);
1190 if (symidx >= ef->ddbsymcnt)
1191 continue;
1192 sym = ef->ddbsymtab + symidx;
1193 /* Local relocs are already done */
1194 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1195 continue;
1196 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1197 elf_obj_lookup)) {
1198 symname = symbol_name(ef, rela->r_info);
1199 printf("link_elf_obj: symbol %s undefined\n",
1200 symname);
1201 return (ENOENT);
1202 }
1203 }
1204 }
1205
1206 /*
1207 * Only clean SHN_FBSD_CACHED for successful return. If we
1208 * modified symbol table for the object but found an
1209 * unresolved symbol, there is no reason to roll back.
1210 */
1211 elf_obj_cleanup_globals_cache(ef);
1212
1213 return (0);
1214 }
1215
1216 static int
link_elf_lookup_symbol(linker_file_t lf,const char * name,c_linker_sym_t * sym)1217 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1218 {
1219 elf_file_t ef = (elf_file_t) lf;
1220 const Elf_Sym *symp;
1221 const char *strp;
1222 int i;
1223
1224 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1225 strp = ef->ddbstrtab + symp->st_name;
1226 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1227 *sym = (c_linker_sym_t) symp;
1228 return 0;
1229 }
1230 }
1231 return ENOENT;
1232 }
1233
1234 static int
link_elf_symbol_values(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval)1235 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1236 linker_symval_t *symval)
1237 {
1238 elf_file_t ef;
1239 const Elf_Sym *es;
1240 caddr_t val;
1241
1242 ef = (elf_file_t) lf;
1243 es = (const Elf_Sym*) sym;
1244 val = (caddr_t)es->st_value;
1245 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1246 symval->name = ef->ddbstrtab + es->st_name;
1247 val = (caddr_t)es->st_value;
1248 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1249 val = ((caddr_t (*)(void))val)();
1250 symval->value = val;
1251 symval->size = es->st_size;
1252 return 0;
1253 }
1254 return ENOENT;
1255 }
1256
1257 static int
link_elf_search_symbol(linker_file_t lf,caddr_t value,c_linker_sym_t * sym,long * diffp)1258 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1259 c_linker_sym_t *sym, long *diffp)
1260 {
1261 elf_file_t ef = (elf_file_t) lf;
1262 u_long off = (uintptr_t) (void *) value;
1263 u_long diff = off;
1264 u_long st_value;
1265 const Elf_Sym *es;
1266 const Elf_Sym *best = NULL;
1267 int i;
1268
1269 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1270 if (es->st_name == 0)
1271 continue;
1272 st_value = es->st_value;
1273 if (off >= st_value) {
1274 if (off - st_value < diff) {
1275 diff = off - st_value;
1276 best = es;
1277 if (diff == 0)
1278 break;
1279 } else if (off - st_value == diff) {
1280 best = es;
1281 }
1282 }
1283 }
1284 if (best == NULL)
1285 *diffp = off;
1286 else
1287 *diffp = diff;
1288 *sym = (c_linker_sym_t) best;
1289
1290 return 0;
1291 }
1292
1293 /*
1294 * Look up a linker set on an ELF system.
1295 */
1296 static int
link_elf_lookup_set(linker_file_t lf,const char * name,void *** startp,void *** stopp,int * countp)1297 link_elf_lookup_set(linker_file_t lf, const char *name,
1298 void ***startp, void ***stopp, int *countp)
1299 {
1300 elf_file_t ef = (elf_file_t)lf;
1301 void **start, **stop;
1302 int i, count;
1303
1304 /* Relative to section number */
1305 for (i = 0; i < ef->nprogtab; i++) {
1306 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1307 strcmp(ef->progtab[i].name + 4, name) == 0) {
1308 start = (void **)ef->progtab[i].addr;
1309 stop = (void **)((char *)ef->progtab[i].addr +
1310 ef->progtab[i].size);
1311 count = stop - start;
1312 if (startp)
1313 *startp = start;
1314 if (stopp)
1315 *stopp = stop;
1316 if (countp)
1317 *countp = count;
1318 return (0);
1319 }
1320 }
1321 return (ESRCH);
1322 }
1323
1324 static int
link_elf_each_function_name(linker_file_t file,int (* callback)(const char *,void *),void * opaque)1325 link_elf_each_function_name(linker_file_t file,
1326 int (*callback)(const char *, void *), void *opaque)
1327 {
1328 elf_file_t ef = (elf_file_t)file;
1329 const Elf_Sym *symp;
1330 int i, error;
1331
1332 /* Exhaustive search */
1333 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1334 if (symp->st_value != 0 &&
1335 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1336 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1337 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1338 if (error)
1339 return (error);
1340 }
1341 }
1342 return (0);
1343 }
1344
1345 static int
link_elf_each_function_nameval(linker_file_t file,linker_function_nameval_callback_t callback,void * opaque)1346 link_elf_each_function_nameval(linker_file_t file,
1347 linker_function_nameval_callback_t callback, void *opaque)
1348 {
1349 linker_symval_t symval;
1350 elf_file_t ef = (elf_file_t)file;
1351 const Elf_Sym* symp;
1352 int i, error;
1353
1354 /* Exhaustive search */
1355 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1356 if (symp->st_value != 0 &&
1357 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1358 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1359 error = link_elf_symbol_values(file,
1360 (c_linker_sym_t)symp, &symval);
1361 if (error)
1362 return (error);
1363 error = callback(file, i, &symval, opaque);
1364 if (error)
1365 return (error);
1366 }
1367 }
1368 return (0);
1369 }
1370
1371 static void
elf_obj_cleanup_globals_cache(elf_file_t ef)1372 elf_obj_cleanup_globals_cache(elf_file_t ef)
1373 {
1374 Elf_Sym *sym;
1375 Elf_Size i;
1376
1377 for (i = 0; i < ef->ddbsymcnt; i++) {
1378 sym = ef->ddbsymtab + i;
1379 if (sym->st_shndx == SHN_FBSD_CACHED) {
1380 sym->st_shndx = SHN_UNDEF;
1381 sym->st_value = 0;
1382 }
1383 }
1384 }
1385
1386 /*
1387 * Symbol lookup function that can be used when the symbol index is known (ie
1388 * in relocations). It uses the symbol index instead of doing a fully fledged
1389 * hash table based lookup when such is valid. For example for local symbols.
1390 * This is not only more efficient, it's also more correct. It's not always
1391 * the case that the symbol can be found through the hash table.
1392 */
1393 static int
elf_obj_lookup(linker_file_t lf,Elf_Size symidx,int deps,Elf_Addr * res)1394 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1395 {
1396 elf_file_t ef = (elf_file_t)lf;
1397 Elf_Sym *sym;
1398 const char *symbol;
1399 Elf_Addr res1;
1400
1401 /* Don't even try to lookup the symbol if the index is bogus. */
1402 if (symidx >= ef->ddbsymcnt) {
1403 *res = 0;
1404 return (EINVAL);
1405 }
1406
1407 sym = ef->ddbsymtab + symidx;
1408
1409 /* Quick answer if there is a definition included. */
1410 if (sym->st_shndx != SHN_UNDEF) {
1411 res1 = (Elf_Addr)sym->st_value;
1412 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC)
1413 res1 = ((Elf_Addr (*)(void))res1)();
1414 *res = res1;
1415 return (0);
1416 }
1417
1418 /* If we get here, then it is undefined and needs a lookup. */
1419 switch (ELF_ST_BIND(sym->st_info)) {
1420 case STB_LOCAL:
1421 /* Local, but undefined? huh? */
1422 *res = 0;
1423 return (EINVAL);
1424
1425 case STB_GLOBAL:
1426 case STB_WEAK:
1427 /* Relative to Data or Function name */
1428 symbol = ef->ddbstrtab + sym->st_name;
1429
1430 /* Force a lookup failure if the symbol name is bogus. */
1431 if (*symbol == 0) {
1432 *res = 0;
1433 return (EINVAL);
1434 }
1435 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1436
1437 /*
1438 * Cache global lookups during module relocation. The failure
1439 * case is particularly expensive for callers, who must scan
1440 * through the entire globals table doing strcmp(). Cache to
1441 * avoid doing such work repeatedly.
1442 *
1443 * After relocation is complete, undefined globals will be
1444 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1445 * above.
1446 */
1447 if (res1 != 0) {
1448 sym->st_shndx = SHN_FBSD_CACHED;
1449 sym->st_value = res1;
1450 *res = res1;
1451 return (0);
1452 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1453 sym->st_value = 0;
1454 *res = 0;
1455 return (0);
1456 }
1457 return (EINVAL);
1458
1459 default:
1460 return (EINVAL);
1461 }
1462 }
1463
1464 static void
link_elf_fix_link_set(elf_file_t ef)1465 link_elf_fix_link_set(elf_file_t ef)
1466 {
1467 static const char startn[] = "__start_";
1468 static const char stopn[] = "__stop_";
1469 Elf_Sym *sym;
1470 const char *sym_name, *linkset_name;
1471 Elf_Addr startp, stopp;
1472 Elf_Size symidx;
1473 int start, i;
1474
1475 startp = stopp = 0;
1476 for (symidx = 1 /* zero entry is special */;
1477 symidx < ef->ddbsymcnt; symidx++) {
1478 sym = ef->ddbsymtab + symidx;
1479 if (sym->st_shndx != SHN_UNDEF)
1480 continue;
1481
1482 sym_name = ef->ddbstrtab + sym->st_name;
1483 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1484 start = 1;
1485 linkset_name = sym_name + sizeof(startn) - 1;
1486 }
1487 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1488 start = 0;
1489 linkset_name = sym_name + sizeof(stopn) - 1;
1490 }
1491 else
1492 continue;
1493
1494 for (i = 0; i < ef->nprogtab; i++) {
1495 if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1496 startp = (Elf_Addr)ef->progtab[i].addr;
1497 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1498 break;
1499 }
1500 }
1501 if (i == ef->nprogtab)
1502 continue;
1503
1504 sym->st_value = start ? startp : stopp;
1505 sym->st_shndx = i;
1506 }
1507 }
1508
1509 static int
link_elf_reloc_local(linker_file_t lf,bool ifuncs)1510 link_elf_reloc_local(linker_file_t lf, bool ifuncs)
1511 {
1512 elf_file_t ef = (elf_file_t)lf;
1513 const Elf_Rel *rellim;
1514 const Elf_Rel *rel;
1515 const Elf_Rela *relalim;
1516 const Elf_Rela *rela;
1517 const Elf_Sym *sym;
1518 Elf_Addr base;
1519 int i;
1520 Elf_Size symidx;
1521
1522 link_elf_fix_link_set(ef);
1523
1524 /* Perform relocations without addend if there are any: */
1525 for (i = 0; i < ef->nreltab; i++) {
1526 rel = ef->reltab[i].rel;
1527 if (rel == NULL) {
1528 link_elf_error(ef->lf.filename, "lost a reltab");
1529 return (ENOEXEC);
1530 }
1531 rellim = rel + ef->reltab[i].nrel;
1532 base = findbase(ef, ef->reltab[i].sec);
1533 if (base == 0) {
1534 link_elf_error(ef->lf.filename, "lost base for reltab");
1535 return (ENOEXEC);
1536 }
1537 for ( ; rel < rellim; rel++) {
1538 symidx = ELF_R_SYM(rel->r_info);
1539 if (symidx >= ef->ddbsymcnt)
1540 continue;
1541 sym = ef->ddbsymtab + symidx;
1542 /* Only do local relocs */
1543 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1544 continue;
1545 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1546 elf_is_ifunc_reloc(rel->r_info)) == ifuncs)
1547 elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1548 elf_obj_lookup);
1549 }
1550 }
1551
1552 /* Perform relocations with addend if there are any: */
1553 for (i = 0; i < ef->nrelatab; i++) {
1554 rela = ef->relatab[i].rela;
1555 if (rela == NULL) {
1556 link_elf_error(ef->lf.filename, "lost a relatab!");
1557 return (ENOEXEC);
1558 }
1559 relalim = rela + ef->relatab[i].nrela;
1560 base = findbase(ef, ef->relatab[i].sec);
1561 if (base == 0) {
1562 link_elf_error(ef->lf.filename, "lost base for reltab");
1563 return (ENOEXEC);
1564 }
1565 for ( ; rela < relalim; rela++) {
1566 symidx = ELF_R_SYM(rela->r_info);
1567 if (symidx >= ef->ddbsymcnt)
1568 continue;
1569 sym = ef->ddbsymtab + symidx;
1570 /* Only do local relocs */
1571 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1572 continue;
1573 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1574 elf_is_ifunc_reloc(rela->r_info)) == ifuncs)
1575 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1576 elf_obj_lookup);
1577 }
1578 }
1579 return (0);
1580 }
1581
1582 static long
link_elf_symtab_get(linker_file_t lf,const Elf_Sym ** symtab)1583 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1584 {
1585 elf_file_t ef = (elf_file_t)lf;
1586
1587 *symtab = ef->ddbsymtab;
1588
1589 if (*symtab == NULL)
1590 return (0);
1591
1592 return (ef->ddbsymcnt);
1593 }
1594
1595 static long
link_elf_strtab_get(linker_file_t lf,caddr_t * strtab)1596 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1597 {
1598 elf_file_t ef = (elf_file_t)lf;
1599
1600 *strtab = ef->ddbstrtab;
1601
1602 if (*strtab == NULL)
1603 return (0);
1604
1605 return (ef->ddbstrcnt);
1606 }
1607