1/*-
2 * Copyright (c) 1998-2000 Doug Rabson
3 * All rights reserved.
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
|
28__FBSDID("$FreeBSD: head/sys/kern/link_elf_obj.c 118094 2003-07-27 17:04:56Z phk $");
|
| 28__FBSDID("$FreeBSD: head/sys/kern/link_elf_obj.c 118771 2003-08-11 07:14:08Z bms $"); |
29
30#include "opt_ddb.h"
31#include "opt_mac.h"
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/kernel.h>
36#include <sys/lock.h>
37#include <sys/mac.h>
38#include <sys/malloc.h>
39#include <sys/mutex.h>
40#include <sys/proc.h>
41#include <sys/namei.h>
42#include <sys/fcntl.h>
43#include <sys/vnode.h>
44#include <sys/linker.h>
45
46#include <machine/elf.h>
47#ifdef GPROF
48#include <machine/profile.h>
49#endif
50
51#include <vm/vm.h>
52#include <vm/vm_param.h>
53#ifdef SPARSE_MAPPING
54#include <vm/vm_object.h>
55#include <vm/vm_kern.h>
56#include <vm/vm_extern.h>
57#endif
58#include <vm/pmap.h>
59#include <vm/vm_map.h>
60
61#include <sys/link_elf.h>
62
63#include "linker_if.h"
64
65typedef struct elf_file {
66 struct linker_file lf; /* Common fields */
67 int preloaded; /* Was file pre-loaded */
68 caddr_t address; /* Relocation address */
69#ifdef SPARSE_MAPPING
70 vm_object_t object; /* VM object to hold file pages */
71#endif
72 Elf_Dyn* dynamic; /* Symbol table etc. */
73 Elf_Hashelt nbuckets; /* DT_HASH info */
74 Elf_Hashelt nchains;
75 const Elf_Hashelt* buckets;
76 const Elf_Hashelt* chains;
77 caddr_t hash;
78 caddr_t strtab; /* DT_STRTAB */
79 int strsz; /* DT_STRSZ */
80 const Elf_Sym* symtab; /* DT_SYMTAB */
81 Elf_Addr* got; /* DT_PLTGOT */
82 const Elf_Rel* pltrel; /* DT_JMPREL */
83 int pltrelsize; /* DT_PLTRELSZ */
84 const Elf_Rela* pltrela; /* DT_JMPREL */
85 int pltrelasize; /* DT_PLTRELSZ */
86 const Elf_Rel* rel; /* DT_REL */
87 int relsize; /* DT_RELSZ */
88 const Elf_Rela* rela; /* DT_RELA */
89 int relasize; /* DT_RELASZ */
90 caddr_t modptr;
91 const Elf_Sym* ddbsymtab; /* The symbol table we are using */
92 long ddbsymcnt; /* Number of symbols */
93 caddr_t ddbstrtab; /* String table */
94 long ddbstrcnt; /* number of bytes in string table */
95 caddr_t symbase; /* malloc'ed symbold base */
96 caddr_t strbase; /* malloc'ed string base */
97#ifdef DDB
98 struct link_map gdb; /* hooks for gdb */
99#endif
100} *elf_file_t;
101
102static int link_elf_link_common_finish(linker_file_t);
103static int link_elf_link_preload(linker_class_t cls,
104 const char*, linker_file_t*);
105static int link_elf_link_preload_finish(linker_file_t);
106static int link_elf_load_file(linker_class_t, const char*, linker_file_t*);
107static int link_elf_lookup_symbol(linker_file_t, const char*,
108 c_linker_sym_t*);
109static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
110static int link_elf_search_symbol(linker_file_t, caddr_t value,
111 c_linker_sym_t* sym, long* diffp);
112
113static void link_elf_unload_file(linker_file_t);
114static void link_elf_unload_preload(linker_file_t);
115static int link_elf_lookup_set(linker_file_t, const char *,
116 void ***, void ***, int *);
117static int link_elf_each_function_name(linker_file_t,
118 int (*)(const char *, void *),
119 void *);
120static void link_elf_reloc_local(linker_file_t);
121
122static kobj_method_t link_elf_methods[] = {
123 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
124 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
125 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
126 KOBJMETHOD(linker_unload, link_elf_unload_file),
127 KOBJMETHOD(linker_load_file, link_elf_load_file),
128 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
129 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
130 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
131 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
132 { 0, 0 }
133};
134
135static struct linker_class link_elf_class = {
136#if ELF_TARG_CLASS == ELFCLASS32
137 "elf32",
138#else
139 "elf64",
140#endif
141 link_elf_methods, sizeof(struct elf_file)
142};
143
144static int parse_dynamic(elf_file_t ef);
145static int relocate_file(elf_file_t ef);
146static int link_elf_preload_parse_symbols(elf_file_t ef);
147
148#ifdef DDB
149static void r_debug_state(struct r_debug *dummy_one,
150 struct link_map *dummy_two);
151
152/*
153 * A list of loaded modules for GDB to use for loading symbols.
154 */
155struct r_debug r_debug;
156
157#define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL);
158
159/*
160 * Function for the debugger to set a breakpoint on to gain control.
161 */
162static void
163r_debug_state(struct r_debug *dummy_one __unused,
164 struct link_map *dummy_two __unused)
165{
166}
167
168static void
169link_elf_add_gdb(struct link_map *l)
170{
171 struct link_map *prev;
172
173 l->l_next = NULL;
174
175 if (r_debug.r_map == NULL) {
176 /* Add first. */
177 l->l_prev = NULL;
178 r_debug.r_map = l;
179 } else {
180 /* Append to list. */
181 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
182 ;
183 l->l_prev = prev;
184 prev->l_next = l;
185 }
186}
187
188static void
189link_elf_delete_gdb(struct link_map *l)
190{
191 if (l->l_prev == NULL) {
192 /* Remove first. */
193 if ((r_debug.r_map = l->l_next) != NULL)
194 l->l_next->l_prev = NULL;
195 } else {
196 /* Remove any but first. */
197 if ((l->l_prev->l_next = l->l_next) != NULL)
198 l->l_next->l_prev = l->l_prev;
199 }
200}
201#endif /* DDB */
202
203#ifdef __ia64__
204Elf_Addr link_elf_get_gp(linker_file_t);
205#endif
206
207/*
208 * The kernel symbol table starts here.
209 */
210extern struct _dynamic _DYNAMIC;
211
212static void
213link_elf_error(const char *s)
214{
215 printf("kldload: %s\n", s);
216}
217
218/*
219 * Actions performed after linking/loading both the preloaded kernel and any
220 * modules; whether preloaded or dynamicly loaded.
221 */
222static int
223link_elf_link_common_finish(linker_file_t lf)
224{
225#ifdef DDB
226 elf_file_t ef = (elf_file_t)lf;
227 char *newfilename;
228#endif
229 int error;
230
231 /* Notify MD code that a module is being loaded. */
232 error = elf_cpu_load_file(lf);
233 if (error)
234 return (error);
235
236#ifdef DDB
237 GDB_STATE(RT_ADD);
238 ef->gdb.l_addr = lf->address;
239 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
240 strcpy(newfilename, lf->filename);
241 ef->gdb.l_name = newfilename;
242 ef->gdb.l_ld = ef->dynamic;
243 link_elf_add_gdb(&ef->gdb);
244 GDB_STATE(RT_CONSISTENT);
245#endif
246
247 return (0);
248}
249
250static void
251link_elf_init(void* arg)
252{
253 Elf_Dyn *dp;
254 caddr_t modptr, baseptr, sizeptr;
255 elf_file_t ef;
256 char *modname;
257
258 linker_add_class(&link_elf_class);
259
260 dp = (Elf_Dyn*) &_DYNAMIC;
261 modname = NULL;
262 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
263 if (modptr == NULL)
264 modptr = preload_search_by_type("elf kernel");
265 if (modptr)
266 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
267 if (modname == NULL)
268 modname = "kernel";
269 linker_kernel_file = linker_make_file(modname, &link_elf_class);
270 if (linker_kernel_file == NULL)
271 panic("link_elf_init: Can't create linker structures for kernel");
272
273 ef = (elf_file_t) linker_kernel_file;
274 ef->preloaded = 1;
275 ef->address = 0;
276#ifdef SPARSE_MAPPING
277 ef->object = 0;
278#endif
279 ef->dynamic = dp;
280
281 if (dp)
282 parse_dynamic(ef);
283 linker_kernel_file->address = (caddr_t) KERNBASE;
284 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
285
286 if (modptr) {
287 ef->modptr = modptr;
288 baseptr = preload_search_info(modptr, MODINFO_ADDR);
289 if (baseptr)
290 linker_kernel_file->address = *(caddr_t *)baseptr;
291 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
292 if (sizeptr)
293 linker_kernel_file->size = *(size_t *)sizeptr;
294 }
295 (void)link_elf_preload_parse_symbols(ef);
296
297#ifdef DDB
298 r_debug.r_map = NULL;
299 r_debug.r_brk = r_debug_state;
300 r_debug.r_state = RT_CONSISTENT;
301#endif
302
303 (void)link_elf_link_common_finish(linker_kernel_file);
304}
305
306SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
307
308static int
309link_elf_preload_parse_symbols(elf_file_t ef)
310{
311 caddr_t pointer;
312 caddr_t ssym, esym, base;
313 caddr_t strtab;
314 int strcnt;
315 Elf_Sym* symtab;
316 int symcnt;
317
318 if (ef->modptr == NULL)
319 return 0;
320 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
321 if (pointer == NULL)
322 return 0;
323 ssym = *(caddr_t *)pointer;
324 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
325 if (pointer == NULL)
326 return 0;
327 esym = *(caddr_t *)pointer;
328
329 base = ssym;
330
331 symcnt = *(long *)base;
332 base += sizeof(long);
333 symtab = (Elf_Sym *)base;
334 base += roundup(symcnt, sizeof(long));
335
336 if (base > esym || base < ssym) {
337 printf("Symbols are corrupt!\n");
338 return EINVAL;
339 }
340
341 strcnt = *(long *)base;
342 base += sizeof(long);
343 strtab = base;
344 base += roundup(strcnt, sizeof(long));
345
346 if (base > esym || base < ssym) {
347 printf("Symbols are corrupt!\n");
348 return EINVAL;
349 }
350
351 ef->ddbsymtab = symtab;
352 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
353 ef->ddbstrtab = strtab;
354 ef->ddbstrcnt = strcnt;
355
356 return 0;
357}
358
359static int
360parse_dynamic(elf_file_t ef)
361{
362 Elf_Dyn *dp;
363 int plttype = DT_REL;
364
365 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
366 switch (dp->d_tag) {
367 case DT_HASH:
368 {
369 /* From src/libexec/rtld-elf/rtld.c */
370 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
371 (ef->address + dp->d_un.d_ptr);
372 ef->nbuckets = hashtab[0];
373 ef->nchains = hashtab[1];
374 ef->buckets = hashtab + 2;
375 ef->chains = ef->buckets + ef->nbuckets;
376 break;
377 }
378 case DT_STRTAB:
379 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
380 break;
381 case DT_STRSZ:
382 ef->strsz = dp->d_un.d_val;
383 break;
384 case DT_SYMTAB:
385 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
386 break;
387 case DT_SYMENT:
388 if (dp->d_un.d_val != sizeof(Elf_Sym))
389 return ENOEXEC;
390 break;
391 case DT_PLTGOT:
392 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
393 break;
394 case DT_REL:
395 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
396 break;
397 case DT_RELSZ:
398 ef->relsize = dp->d_un.d_val;
399 break;
400 case DT_RELENT:
401 if (dp->d_un.d_val != sizeof(Elf_Rel))
402 return ENOEXEC;
403 break;
404 case DT_JMPREL:
405 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
406 break;
407 case DT_PLTRELSZ:
408 ef->pltrelsize = dp->d_un.d_val;
409 break;
410 case DT_RELA:
411 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
412 break;
413 case DT_RELASZ:
414 ef->relasize = dp->d_un.d_val;
415 break;
416 case DT_RELAENT:
417 if (dp->d_un.d_val != sizeof(Elf_Rela))
418 return ENOEXEC;
419 break;
420 case DT_PLTREL:
421 plttype = dp->d_un.d_val;
422 if (plttype != DT_REL && plttype != DT_RELA)
423 return ENOEXEC;
424 break;
425#ifdef DDB
426 case DT_DEBUG:
427 dp->d_un.d_ptr = (Elf_Addr) &r_debug;
428 break;
429#endif
430 }
431 }
432
433 if (plttype == DT_RELA) {
434 ef->pltrela = (const Elf_Rela *) ef->pltrel;
435 ef->pltrel = NULL;
436 ef->pltrelasize = ef->pltrelsize;
437 ef->pltrelsize = 0;
438 }
439
440 ef->ddbsymtab = ef->symtab;
441 ef->ddbsymcnt = ef->nchains;
442 ef->ddbstrtab = ef->strtab;
443 ef->ddbstrcnt = ef->strsz;
444
445 return 0;
446}
447
448static int
449link_elf_link_preload(linker_class_t cls,
450 const char* filename, linker_file_t *result)
451{
452 caddr_t modptr, baseptr, sizeptr, dynptr;
453 char *type;
454 elf_file_t ef;
455 linker_file_t lf;
456 int error;
457 vm_offset_t dp;
458
459 /* Look to see if we have the file preloaded */
460 modptr = preload_search_by_name(filename);
461 if (modptr == NULL)
462 return ENOENT;
463
464 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
465 baseptr = preload_search_info(modptr, MODINFO_ADDR);
466 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
467 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
468 if (type == NULL ||
469 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
470 strcmp(type, "elf module") != 0))
471 return (EFTYPE);
472 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
473 return (EINVAL);
474
475 lf = linker_make_file(filename, &link_elf_class);
476 if (lf == NULL) {
477 return ENOMEM;
478 }
479
480 ef = (elf_file_t) lf;
481 ef->preloaded = 1;
482 ef->modptr = modptr;
483 ef->address = *(caddr_t *)baseptr;
484#ifdef SPARSE_MAPPING
485 ef->object = 0;
486#endif
487 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
488 ef->dynamic = (Elf_Dyn *)dp;
489 lf->address = ef->address;
490 lf->size = *(size_t *)sizeptr;
491
492 error = parse_dynamic(ef);
493 if (error) {
494 linker_file_unload(lf);
495 return error;
496 }
497 link_elf_reloc_local(lf);
498 *result = lf;
499 return (0);
500}
501
502static int
503link_elf_link_preload_finish(linker_file_t lf)
504{
505 elf_file_t ef;
506 int error;
507
508 ef = (elf_file_t) lf;
509#if 0 /* this will be more trouble than it's worth for now */
510 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
511 if (dp->d_tag != DT_NEEDED)
512 continue;
513 modname = ef->strtab + dp->d_un.d_val;
514 error = linker_load_module(modname, lf);
515 if (error)
516 goto out;
517 }
518#endif
519 error = relocate_file(ef);
520 if (error)
521 return error;
522 (void)link_elf_preload_parse_symbols(ef);
523
524 return (link_elf_link_common_finish(lf));
525}
526
527static int
528link_elf_load_file(linker_class_t cls, const char* filename,
529 linker_file_t* result)
530{
531 struct nameidata nd;
532 struct thread* td = curthread; /* XXX */
533 Elf_Ehdr *hdr;
534 caddr_t firstpage;
535 int nbytes, i;
536 Elf_Phdr *phdr;
537 Elf_Phdr *phlimit;
538 Elf_Phdr *segs[2];
539 int nsegs;
540 Elf_Phdr *phdyn;
541 Elf_Phdr *phphdr;
542 caddr_t mapbase;
543 size_t mapsize;
544 Elf_Off base_offset;
545 Elf_Addr base_vaddr;
546 Elf_Addr base_vlimit;
547 int error = 0;
548 int resid, flags;
549 elf_file_t ef;
550 linker_file_t lf;
551 Elf_Shdr *shdr;
552 int symtabindex;
553 int symstrindex;
554 int symcnt;
555 int strcnt;
556
557 GIANT_REQUIRED;
558
559 shdr = NULL;
560 lf = NULL;
561
562 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
563 flags = FREAD;
564 error = vn_open(&nd, &flags, 0, -1);
565 if (error)
566 return error;
567 NDFREE(&nd, NDF_ONLY_PNBUF);
568#ifdef MAC
569 error = mac_check_kld_load(curthread->td_ucred, nd.ni_vp);
570 if (error) {
571 firstpage = NULL;
572 goto out;
573 }
574#endif
575
576 /*
577 * Read the elf header from the file.
578 */
579 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
580 if (firstpage == NULL) {
581 error = ENOMEM;
582 goto out;
583 }
584 hdr = (Elf_Ehdr *)firstpage;
585 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
586 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
587 &resid, td);
588 nbytes = PAGE_SIZE - resid;
589 if (error)
590 goto out;
591
592 if (!IS_ELF(*hdr)) {
593 error = ENOEXEC;
594 goto out;
595 }
596
597 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
598 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
599 link_elf_error("Unsupported file layout");
600 error = ENOEXEC;
601 goto out;
602 }
603 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
604 || hdr->e_version != EV_CURRENT) {
605 link_elf_error("Unsupported file version");
606 error = ENOEXEC;
607 goto out;
608 }
609 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
610 link_elf_error("Unsupported file type");
611 error = ENOEXEC;
612 goto out;
613 }
614 if (hdr->e_machine != ELF_TARG_MACH) {
615 link_elf_error("Unsupported machine");
616 error = ENOEXEC;
617 goto out;
618 }
619
620 /*
621 * We rely on the program header being in the first page. This is
622 * not strictly required by the ABI specification, but it seems to
623 * always true in practice. And, it simplifies things considerably.
624 */
625 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
626 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
627 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
628 link_elf_error("Unreadable program headers");
629
630 /*
631 * Scan the program header entries, and save key information.
632 *
633 * We rely on there being exactly two load segments, text and data,
634 * in that order.
635 */
636 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
637 phlimit = phdr + hdr->e_phnum;
638 nsegs = 0;
639 phdyn = NULL;
640 phphdr = NULL;
641 while (phdr < phlimit) {
642 switch (phdr->p_type) {
643
644 case PT_LOAD:
645 if (nsegs == 2) {
646 link_elf_error("Too many sections");
647 error = ENOEXEC;
648 goto out;
649 }
650 /*
651 * XXX: We just trust they come in right order ??
652 */
653 segs[nsegs] = phdr;
654 ++nsegs;
655 break;
656
657 case PT_PHDR:
658 phphdr = phdr;
659 break;
660
661 case PT_DYNAMIC:
662 phdyn = phdr;
663 break;
664
665 case PT_INTERP:
666 link_elf_error("Unsupported file type");
667 error = ENOEXEC;
668 goto out;
669 }
670
671 ++phdr;
672 }
673 if (phdyn == NULL) {
674 link_elf_error("Object is not dynamically-linked");
675 error = ENOEXEC;
676 goto out;
677 }
678 if (nsegs != 2) {
679 link_elf_error("Too few sections");
680 error = ENOEXEC;
681 goto out;
682 }
683
684 /*
685 * Allocate the entire address space of the object, to stake out our
686 * contiguous region, and to establish the base address for relocation.
687 */
688 base_offset = trunc_page(segs[0]->p_offset);
689 base_vaddr = trunc_page(segs[0]->p_vaddr);
690 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
691 mapsize = base_vlimit - base_vaddr;
692
693 lf = linker_make_file(filename, &link_elf_class);
694 if (!lf) {
695 error = ENOMEM;
696 goto out;
697 }
698
699 ef = (elf_file_t) lf;
700#ifdef SPARSE_MAPPING
701 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
702 if (ef->object == NULL) {
703 error = ENOMEM;
704 goto out;
705 }
706 vm_object_reference(ef->object);
707 ef->address = (caddr_t) vm_map_min(kernel_map);
708 error = vm_map_find(kernel_map, ef->object, 0,
709 (vm_offset_t *) &ef->address,
710 mapsize, 1,
711 VM_PROT_ALL, VM_PROT_ALL, 0);
712 if (error) {
713 vm_object_deallocate(ef->object);
714 ef->object = 0;
715 goto out;
716 }
717#else
718 ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
719 if (!ef->address) {
720 error = ENOMEM;
721 goto out;
722 }
723#endif
724 mapbase = ef->address;
725
726 /*
727 * Read the text and data sections and zero the bss.
728 */
729 for (i = 0; i < 2; i++) {
730 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
731 error = vn_rdwr(UIO_READ, nd.ni_vp,
732 segbase, segs[i]->p_filesz, segs[i]->p_offset,
733 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
734 &resid, td);
735 if (error) {
736 goto out;
737 }
738 bzero(segbase + segs[i]->p_filesz,
739 segs[i]->p_memsz - segs[i]->p_filesz);
740
741#ifdef SPARSE_MAPPING
742 /*
743 * Wire down the pages
744 */
745 vm_map_wire(kernel_map,
746 (vm_offset_t) segbase,
747 (vm_offset_t) segbase + segs[i]->p_memsz,
|
748 FALSE);
|
| 748 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); |
749#endif
750 }
751
752#ifdef GPROF
753 /* Update profiling information with the new text segment. */
754 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
755 segs[0]->p_memsz));
756#endif
757
758 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
759
760 lf->address = ef->address;
761 lf->size = mapsize;
762
763 error = parse_dynamic(ef);
764 if (error)
765 goto out;
766 link_elf_reloc_local(lf);
767
768 error = linker_load_dependencies(lf);
769 if (error)
770 goto out;
771#if 0 /* this will be more trouble than it's worth for now */
772 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
773 if (dp->d_tag != DT_NEEDED)
774 continue;
775 modname = ef->strtab + dp->d_un.d_val;
776 error = linker_load_module(modname, lf);
777 if (error)
778 goto out;
779 }
780#endif
781 error = relocate_file(ef);
782 if (error)
783 goto out;
784
785 /* Try and load the symbol table if it's present. (you can strip it!) */
786 nbytes = hdr->e_shnum * hdr->e_shentsize;
787 if (nbytes == 0 || hdr->e_shoff == 0)
788 goto nosyms;
789 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
790 if (shdr == NULL) {
791 error = ENOMEM;
792 goto out;
793 }
794 error = vn_rdwr(UIO_READ, nd.ni_vp,
795 (caddr_t)shdr, nbytes, hdr->e_shoff,
796 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
797 &resid, td);
798 if (error)
799 goto out;
800 symtabindex = -1;
801 symstrindex = -1;
802 for (i = 0; i < hdr->e_shnum; i++) {
803 if (shdr[i].sh_type == SHT_SYMTAB) {
804 symtabindex = i;
805 symstrindex = shdr[i].sh_link;
806 }
807 }
808 if (symtabindex < 0 || symstrindex < 0)
809 goto nosyms;
810
811 symcnt = shdr[symtabindex].sh_size;
812 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
813 strcnt = shdr[symstrindex].sh_size;
814 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
815
816 if (ef->symbase == NULL || ef->strbase == NULL) {
817 error = ENOMEM;
818 goto out;
819 }
820 error = vn_rdwr(UIO_READ, nd.ni_vp,
821 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
822 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
823 &resid, td);
824 if (error)
825 goto out;
826 error = vn_rdwr(UIO_READ, nd.ni_vp,
827 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
828 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
829 &resid, td);
830 if (error)
831 goto out;
832
833 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
834 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
835 ef->ddbstrcnt = strcnt;
836 ef->ddbstrtab = ef->strbase;
837
838 error = link_elf_link_common_finish(lf);
839 if (error)
840 goto out;
841
842nosyms:
843
844 *result = lf;
845
846out:
847 if (error && lf)
848 linker_file_unload(lf);
849 if (shdr)
850 free(shdr, M_LINKER);
851 if (firstpage)
852 free(firstpage, M_LINKER);
853 VOP_UNLOCK(nd.ni_vp, 0, td);
854 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
855
856 return error;
857}
858
859static void
860link_elf_unload_file(linker_file_t file)
861{
862 elf_file_t ef = (elf_file_t) file;
863
864#ifdef DDB
865 if (ef->gdb.l_ld) {
866 GDB_STATE(RT_DELETE);
867 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
868 link_elf_delete_gdb(&ef->gdb);
869 GDB_STATE(RT_CONSISTENT);
870 }
871#endif
872
873 /* Notify MD code that a module is being unloaded. */
874 elf_cpu_unload_file(file);
875
876 if (ef->preloaded) {
877 link_elf_unload_preload(file);
878 return;
879 }
880
881#ifdef SPARSE_MAPPING
882 if (ef->object) {
883 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
884 (vm_offset_t) ef->address
885 + (ef->object->size << PAGE_SHIFT));
886 vm_object_deallocate(ef->object);
887 }
888#else
889 if (ef->address)
890 free(ef->address, M_LINKER);
891#endif
892 if (ef->symbase)
893 free(ef->symbase, M_LINKER);
894 if (ef->strbase)
895 free(ef->strbase, M_LINKER);
896}
897
898static void
899link_elf_unload_preload(linker_file_t file)
900{
901 if (file->filename)
902 preload_delete_name(file->filename);
903}
904
905static const char *
906symbol_name(elf_file_t ef, Elf_Word r_info)
907{
908 const Elf_Sym *ref;
909
910 if (ELF_R_SYM(r_info)) {
911 ref = ef->symtab + ELF_R_SYM(r_info);
912 return ef->strtab + ref->st_name;
913 } else
914 return NULL;
915}
916
917static int
918relocate_file(elf_file_t ef)
919{
920 const Elf_Rel *rellim;
921 const Elf_Rel *rel;
922 const Elf_Rela *relalim;
923 const Elf_Rela *rela;
924 const char *symname;
925
926 /* Perform relocations without addend if there are any: */
927 rel = ef->rel;
928 if (rel) {
929 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
930 while (rel < rellim) {
931 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) {
932 symname = symbol_name(ef, rel->r_info);
933 printf("link_elf: symbol %s undefined\n", symname);
934 return ENOENT;
935 }
936 rel++;
937 }
938 }
939
940 /* Perform relocations with addend if there are any: */
941 rela = ef->rela;
942 if (rela) {
943 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
944 while (rela < relalim) {
945 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) {
946 symname = symbol_name(ef, rela->r_info);
947 printf("link_elf: symbol %s undefined\n", symname);
948 return ENOENT;
949 }
950 rela++;
951 }
952 }
953
954 /* Perform PLT relocations without addend if there are any: */
955 rel = ef->pltrel;
956 if (rel) {
957 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
958 while (rel < rellim) {
959 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) {
960 symname = symbol_name(ef, rel->r_info);
961 printf("link_elf: symbol %s undefined\n", symname);
962 return ENOENT;
963 }
964 rel++;
965 }
966 }
967
968 /* Perform relocations with addend if there are any: */
969 rela = ef->pltrela;
970 if (rela) {
971 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
972 while (rela < relalim) {
973 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) {
974 symname = symbol_name(ef, rela->r_info);
975 printf("link_elf: symbol %s undefined\n", symname);
976 return ENOENT;
977 }
978 rela++;
979 }
980 }
981
982 return 0;
983}
984
985/*
986 * Hash function for symbol table lookup. Don't even think about changing
987 * this. It is specified by the System V ABI.
988 */
989static unsigned long
990elf_hash(const char *name)
991{
992 const unsigned char *p = (const unsigned char *) name;
993 unsigned long h = 0;
994 unsigned long g;
995
996 while (*p != '\0') {
997 h = (h << 4) + *p++;
998 if ((g = h & 0xf0000000) != 0)
999 h ^= g >> 24;
1000 h &= ~g;
1001 }
1002 return h;
1003}
1004
1005static int
1006link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1007{
1008 elf_file_t ef = (elf_file_t) lf;
1009 unsigned long symnum;
1010 const Elf_Sym* symp;
1011 const char *strp;
1012 unsigned long hash;
1013 int i;
1014
1015 /* First, search hashed global symbols */
1016 hash = elf_hash(name);
1017 symnum = ef->buckets[hash % ef->nbuckets];
1018
1019 while (symnum != STN_UNDEF) {
1020 if (symnum >= ef->nchains) {
1021 printf("link_elf_lookup_symbol: corrupt symbol table\n");
1022 return ENOENT;
1023 }
1024
1025 symp = ef->symtab + symnum;
1026 if (symp->st_name == 0) {
1027 printf("link_elf_lookup_symbol: corrupt symbol table\n");
1028 return ENOENT;
1029 }
1030
1031 strp = ef->strtab + symp->st_name;
1032
1033 if (strcmp(name, strp) == 0) {
1034 if (symp->st_shndx != SHN_UNDEF ||
1035 (symp->st_value != 0 &&
1036 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1037 *sym = (c_linker_sym_t) symp;
1038 return 0;
1039 } else
1040 return ENOENT;
1041 }
1042
1043 symnum = ef->chains[symnum];
1044 }
1045
1046 /* If we have not found it, look at the full table (if loaded) */
1047 if (ef->symtab == ef->ddbsymtab)
1048 return ENOENT;
1049
1050 /* Exhaustive search */
1051 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1052 strp = ef->ddbstrtab + symp->st_name;
1053 if (strcmp(name, strp) == 0) {
1054 if (symp->st_shndx != SHN_UNDEF ||
1055 (symp->st_value != 0 &&
1056 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1057 *sym = (c_linker_sym_t) symp;
1058 return 0;
1059 } else
1060 return ENOENT;
1061 }
1062 }
1063
1064 return ENOENT;
1065}
1066
1067static int
1068link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
1069{
1070 elf_file_t ef = (elf_file_t) lf;
1071 const Elf_Sym* es = (const Elf_Sym*) sym;
1072
1073 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1074 symval->name = ef->strtab + es->st_name;
1075 symval->value = (caddr_t) ef->address + es->st_value;
1076 symval->size = es->st_size;
1077 return 0;
1078 }
1079 if (ef->symtab == ef->ddbsymtab)
1080 return ENOENT;
1081 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1082 symval->name = ef->ddbstrtab + es->st_name;
1083 symval->value = (caddr_t) ef->address + es->st_value;
1084 symval->size = es->st_size;
1085 return 0;
1086 }
1087 return ENOENT;
1088}
1089
1090static int
1091link_elf_search_symbol(linker_file_t lf, caddr_t value,
1092 c_linker_sym_t* sym, long* diffp)
1093{
1094 elf_file_t ef = (elf_file_t) lf;
1095 u_long off = (uintptr_t) (void *) value;
1096 u_long diff = off;
1097 u_long st_value;
1098 const Elf_Sym* es;
1099 const Elf_Sym* best = 0;
1100 int i;
1101
1102 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1103 if (es->st_name == 0)
1104 continue;
1105 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1106 if (off >= st_value) {
1107 if (off - st_value < diff) {
1108 diff = off - st_value;
1109 best = es;
1110 if (diff == 0)
1111 break;
1112 } else if (off - st_value == diff) {
1113 best = es;
1114 }
1115 }
1116 }
1117 if (best == 0)
1118 *diffp = off;
1119 else
1120 *diffp = diff;
1121 *sym = (c_linker_sym_t) best;
1122
1123 return 0;
1124}
1125
1126/*
1127 * Look up a linker set on an ELF system.
1128 */
1129static int
1130link_elf_lookup_set(linker_file_t lf, const char *name,
1131 void ***startp, void ***stopp, int *countp)
1132{
1133 c_linker_sym_t sym;
1134 linker_symval_t symval;
1135 char *setsym;
1136 void **start, **stop;
1137 int len, error = 0, count;
1138
1139 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1140 setsym = malloc(len, M_LINKER, M_WAITOK);
1141 if (setsym == NULL)
1142 return ENOMEM;
1143
1144 /* get address of first entry */
1145 snprintf(setsym, len, "%s%s", "__start_set_", name);
1146 error = link_elf_lookup_symbol(lf, setsym, &sym);
1147 if (error)
1148 goto out;
1149 link_elf_symbol_values(lf, sym, &symval);
1150 if (symval.value == 0) {
1151 error = ESRCH;
1152 goto out;
1153 }
1154 start = (void **)symval.value;
1155
1156 /* get address of last entry */
1157 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1158 error = link_elf_lookup_symbol(lf, setsym, &sym);
1159 if (error)
1160 goto out;
1161 link_elf_symbol_values(lf, sym, &symval);
1162 if (symval.value == 0) {
1163 error = ESRCH;
1164 goto out;
1165 }
1166 stop = (void **)symval.value;
1167
1168 /* and the number of entries */
1169 count = stop - start;
1170
1171 /* and copy out */
1172 if (startp)
1173 *startp = start;
1174 if (stopp)
1175 *stopp = stop;
1176 if (countp)
1177 *countp = count;
1178
1179out:
1180 free(setsym, M_LINKER);
1181 return error;
1182}
1183
1184static int
1185link_elf_each_function_name(linker_file_t file,
1186 int (*callback)(const char *, void *), void *opaque) {
1187 elf_file_t ef = (elf_file_t)file;
1188 const Elf_Sym* symp;
1189 int i, error;
1190
1191 /* Exhaustive search */
1192 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1193 if (symp->st_value != 0 &&
1194 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1195 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1196 if (error)
1197 return (error);
1198 }
1199 }
1200 return (0);
1201}
1202
1203#ifdef __ia64__
1204/*
1205 * Each KLD has its own GP. The GP value for each load module is given by
1206 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
1207 * don't have direct access to the ELF file structure. The link_elf_get_gp()
1208 * function returns the GP given a pointer to a generic linker file struct.
1209 */
1210Elf_Addr
1211link_elf_get_gp(linker_file_t lf)
1212{
1213 elf_file_t ef = (elf_file_t)lf;
1214 return (Elf_Addr)ef->got;
1215}
1216#endif
1217
1218const Elf_Sym *
1219elf_get_sym(linker_file_t lf, Elf_Word symidx)
1220{
1221 elf_file_t ef = (elf_file_t)lf;
1222
1223 if (symidx >= ef->nchains)
1224 return (NULL);
1225 return (ef->symtab + symidx);
1226}
1227
1228const char *
1229elf_get_symname(linker_file_t lf, Elf_Word symidx)
1230{
1231 elf_file_t ef = (elf_file_t)lf;
1232 const Elf_Sym *sym;
1233
1234 if (symidx >= ef->nchains)
1235 return (NULL);
1236 sym = ef->symtab + symidx;
1237 return (ef->strtab + sym->st_name);
1238}
1239
1240/*
1241 * Symbol lookup function that can be used when the symbol index is known (ie
1242 * in relocations). It uses the symbol index instead of doing a fully fledged
1243 * hash table based lookup when such is valid. For example for local symbols.
1244 * This is not only more efficient, it's also more correct. It's not always
1245 * the case that the symbol can be found through the hash table.
1246 */
1247Elf_Addr
1248elf_lookup(linker_file_t lf, Elf_Word symidx, int deps)
1249{
1250 elf_file_t ef = (elf_file_t)lf;
1251 const Elf_Sym *sym;
1252 const char *symbol;
1253
1254 /* Don't even try to lookup the symbol if the index is bogus. */
1255 if (symidx >= ef->nchains)
1256 return (0);
1257
1258 sym = ef->symtab + symidx;
1259
1260 /*
1261 * Don't do a full lookup when the symbol is local. It may even
1262 * fail because it may not be found through the hash table.
1263 */
1264 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1265 /* Force lookup failure when we have an insanity. */
1266 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1267 return (0);
1268 return ((Elf_Addr)ef->address + sym->st_value);
1269 }
1270
1271 /*
1272 * XXX we can avoid doing a hash table based lookup for global
1273 * symbols as well. This however is not always valid, so we'll
1274 * just do it the hard way for now. Performance tweaks can
1275 * always be added.
1276 */
1277
1278 symbol = ef->strtab + sym->st_name;
1279
1280 /* Force a lookup failure if the symbol name is bogus. */
1281 if (*symbol == 0)
1282 return (0);
1283
1284 return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1285}
1286
1287static void
1288link_elf_reloc_local(linker_file_t lf)
1289{
1290 const Elf_Rel *rellim;
1291 const Elf_Rel *rel;
1292 const Elf_Rela *relalim;
1293 const Elf_Rela *rela;
1294 elf_file_t ef = (elf_file_t)lf;
1295
1296 /* Perform relocations without addend if there are any: */
1297 if ((rel = ef->rel) != NULL) {
1298 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1299 while (rel < rellim) {
1300 elf_reloc_local(lf, rel, ELF_RELOC_REL);
1301 rel++;
1302 }
1303 }
1304
1305 /* Perform relocations with addend if there are any: */
1306 if ((rela = ef->rela) != NULL) {
1307 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1308 while (rela < relalim) {
1309 elf_reloc_local(lf, rela, ELF_RELOC_RELA);
1310 rela++;
1311 }
1312 }
1313}
|