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 * $FreeBSD: head/sys/kern/link_elf_obj.c 85736 2001-10-30 15:21:45Z green $
27 */
28
29#include "opt_ddb.h"
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/kernel.h>
34#include <sys/lock.h>
35#include <sys/malloc.h>
36#include <sys/mutex.h>
37#include <sys/proc.h>
38#include <sys/namei.h>
39#include <sys/fcntl.h>
40#include <sys/vnode.h>
41#include <sys/linker.h>
42
43#include <machine/elf.h>
44#ifdef GPROF
45#include <machine/profile.h>
46#endif
47
48#include <vm/vm.h>
49#include <vm/vm_param.h>
50#ifdef SPARSE_MAPPING
51#include <vm/vm_object.h>
52#include <vm/vm_kern.h>
53#include <vm/vm_extern.h>
54#endif
55#include <vm/pmap.h>
56#include <vm/vm_map.h>
57
58#ifdef __AOUT__
59#include <nlist.h>
60#endif
61#include <link.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_preload(linker_class_t cls,
103 const char*, linker_file_t*);
104static int link_elf_link_preload_finish(linker_file_t);
105static int link_elf_load_file(linker_class_t, const char*, linker_file_t*);
106static int link_elf_lookup_symbol(linker_file_t, const char*,
107 c_linker_sym_t*);
108static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
109static int link_elf_search_symbol(linker_file_t, caddr_t value,
110 c_linker_sym_t* sym, long* diffp);
111
112static void link_elf_unload_file(linker_file_t);
113static void link_elf_unload_preload(linker_file_t);
114static int link_elf_lookup_set(linker_file_t, const char *,
115 void ***, void ***, int *);
116static int link_elf_each_function_name(linker_file_t,
117 int (*)(const char *, void *),
118 void *);
119
120static kobj_method_t link_elf_methods[] = {
121 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
122 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
123 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
124 KOBJMETHOD(linker_unload, link_elf_unload_file),
125 KOBJMETHOD(linker_load_file, link_elf_load_file),
126 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
127 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
128 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
129 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
130 { 0, 0 }
131};
132
133static struct linker_class link_elf_class = {
134#if ELF_TARG_CLASS == ELFCLASS32
135 "elf32",
136#else
137 "elf64",
138#endif
139 link_elf_methods, sizeof(struct elf_file)
140};
141
142static int parse_dynamic(elf_file_t ef);
143static int relocate_file(elf_file_t ef);
144static int link_elf_preload_parse_symbols(elf_file_t ef);
145
146#ifdef DDB
147static void r_debug_state(struct r_debug *dummy_one,
148 struct link_map *dummy_two);
149
150/*
151 * A list of loaded modules for GDB to use for loading symbols.
152 */
153struct r_debug r_debug;
154
155#define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL);
156
157/*
158 * Function for the debugger to set a breakpoint on to gain control.
159 */
160void
161r_debug_state(struct r_debug *dummy_one __unused,
162 struct link_map *dummy_two __unused)
163{
164}
165
166#endif
167
168/*
169 * The kernel symbol table starts here.
170 */
171extern struct _dynamic _DYNAMIC;
172
173static void
174link_elf_init(void* arg)
175{
176#ifdef __ELF__
177 Elf_Dyn *dp;
178 caddr_t modptr, baseptr, sizeptr;
179 elf_file_t ef;
180 char *modname;
181#ifdef DDB
182 char *newfilename;
183#endif
184#endif
185
186 linker_add_class(&link_elf_class);
187
188#ifdef __ELF__
189 dp = (Elf_Dyn*) &_DYNAMIC;
190 modname = NULL;
191 modptr = preload_search_by_type("elf kernel");
192 if (modptr)
193 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
194 if (modname == NULL)
195 modname = "kernel";
196 linker_kernel_file = linker_make_file(modname, &link_elf_class);
197 if (linker_kernel_file == NULL)
198 panic("link_elf_init: Can't create linker structures for kernel");
199
200 ef = (elf_file_t) linker_kernel_file;
201 ef->preloaded = 1;
202 ef->address = 0;
203#ifdef SPARSE_MAPPING
204 ef->object = 0;
205#endif
206 ef->dynamic = dp;
207
208 if (dp)
209 parse_dynamic(ef);
210 linker_kernel_file->address = (caddr_t) KERNBASE;
211 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
212
213 if (modptr) {
214 ef->modptr = modptr;
215 baseptr = preload_search_info(modptr, MODINFO_ADDR);
216 if (baseptr)
217 linker_kernel_file->address = *(caddr_t *)baseptr;
218 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
219 if (sizeptr)
220 linker_kernel_file->size = *(size_t *)sizeptr;
221 }
222 (void)link_elf_preload_parse_symbols(ef);
223
224#ifdef DDB
225 ef->gdb.l_addr = linker_kernel_file->address;
226 newfilename = malloc(strlen(modname) + 1, M_LINKER, M_WAITOK);
227 strcpy(newfilename, modname);
228 ef->gdb.l_name = newfilename;
229 ef->gdb.l_ld = dp;
230 ef->gdb.l_prev = 0;
231 ef->gdb.l_next = 0;
232
233 r_debug.r_map = &ef->gdb;
234 r_debug.r_brk = r_debug_state;
235 r_debug.r_state = RT_CONSISTENT;
236
237 r_debug_state(NULL, NULL); /* say hello to gdb! */
238#endif
239
240#endif
241}
242
243SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
244
245static int
246link_elf_preload_parse_symbols(elf_file_t ef)
247{
248 caddr_t pointer;
249 caddr_t ssym, esym, base;
250 caddr_t strtab;
251 int strcnt;
252 Elf_Sym* symtab;
253 int symcnt;
254
255 if (ef->modptr == NULL)
256 return 0;
257 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
258 if (pointer == NULL)
259 return 0;
260 ssym = *(caddr_t *)pointer;
261 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
262 if (pointer == NULL)
263 return 0;
264 esym = *(caddr_t *)pointer;
265
266 base = ssym;
267
268 symcnt = *(long *)base;
269 base += sizeof(long);
270 symtab = (Elf_Sym *)base;
271 base += roundup(symcnt, sizeof(long));
272
273 if (base > esym || base < ssym) {
274 printf("Symbols are corrupt!\n");
275 return EINVAL;
276 }
277
278 strcnt = *(long *)base;
279 base += sizeof(long);
280 strtab = base;
281 base += roundup(strcnt, sizeof(long));
282
283 if (base > esym || base < ssym) {
284 printf("Symbols are corrupt!\n");
285 return EINVAL;
286 }
287
288 ef->ddbsymtab = symtab;
289 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
290 ef->ddbstrtab = strtab;
291 ef->ddbstrcnt = strcnt;
292
293 return 0;
294}
295
296static int
297parse_dynamic(elf_file_t ef)
298{
299 Elf_Dyn *dp;
300 int plttype = DT_REL;
301
302 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
303 switch (dp->d_tag) {
304 case DT_HASH:
305 {
306 /* From src/libexec/rtld-elf/rtld.c */
307 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
308 (ef->address + dp->d_un.d_ptr);
309 ef->nbuckets = hashtab[0];
310 ef->nchains = hashtab[1];
311 ef->buckets = hashtab + 2;
312 ef->chains = ef->buckets + ef->nbuckets;
313 break;
314 }
315 case DT_STRTAB:
316 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
317 break;
318 case DT_STRSZ:
319 ef->strsz = dp->d_un.d_val;
320 break;
321 case DT_SYMTAB:
322 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
323 break;
324 case DT_SYMENT:
325 if (dp->d_un.d_val != sizeof(Elf_Sym))
326 return ENOEXEC;
327 break;
328 case DT_PLTGOT:
329 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
330 break;
331 case DT_REL:
332 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
333 break;
334 case DT_RELSZ:
335 ef->relsize = dp->d_un.d_val;
336 break;
337 case DT_RELENT:
338 if (dp->d_un.d_val != sizeof(Elf_Rel))
339 return ENOEXEC;
340 break;
341 case DT_JMPREL:
342 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
343 break;
344 case DT_PLTRELSZ:
345 ef->pltrelsize = dp->d_un.d_val;
346 break;
347 case DT_RELA:
348 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
349 break;
350 case DT_RELASZ:
351 ef->relasize = dp->d_un.d_val;
352 break;
353 case DT_RELAENT:
354 if (dp->d_un.d_val != sizeof(Elf_Rela))
355 return ENOEXEC;
356 break;
357 case DT_PLTREL:
358 plttype = dp->d_un.d_val;
359 if (plttype != DT_REL && plttype != DT_RELA)
360 return ENOEXEC;
361 break;
362#ifdef DDB
363 case DT_DEBUG:
364 dp->d_un.d_ptr = (Elf_Addr) &r_debug;
365 break;
366#endif
367 }
368 }
369
370 if (plttype == DT_RELA) {
371 ef->pltrela = (const Elf_Rela *) ef->pltrel;
372 ef->pltrel = NULL;
373 ef->pltrelasize = ef->pltrelsize;
374 ef->pltrelsize = 0;
375 }
376
377 ef->ddbsymtab = ef->symtab;
378 ef->ddbsymcnt = ef->nchains;
379 ef->ddbstrtab = ef->strtab;
380 ef->ddbstrcnt = ef->strsz;
381
382 return 0;
383}
384
385static void
386link_elf_error(const char *s)
387{
388 printf("kldload: %s\n", s);
389}
390
391#ifdef DDB
392
393static void
394link_elf_add_gdb(struct link_map *l)
395{
396 struct link_map *prev;
397
398 /*
399 * Scan to the end of the list.
400 */
401 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
402 ;
403
404 /* Link in the new entry. */
405 l->l_prev = prev;
406 l->l_next = prev->l_next;
407 prev->l_next = l;
408}
409
410static void
411link_elf_delete_gdb(struct link_map *l)
412{
413 if (l->l_prev == NULL) {
414 if ((r_debug.r_map = l->l_next) != NULL)
415 l->l_next->l_prev = NULL;
416 return;
417 }
418
419 if ((l->l_prev->l_next = l->l_next) != NULL)
420 l->l_next->l_prev = l->l_prev;
421}
422
423#endif /* DDB */
424
425static int
426link_elf_link_preload(linker_class_t cls,
427 const char* filename, linker_file_t *result)
428{
429 caddr_t modptr, baseptr, sizeptr, dynptr;
430 char *type;
431 elf_file_t ef;
432 linker_file_t lf;
433 int error;
434 vm_offset_t dp;
435
436 /* Look to see if we have the file preloaded */
437 modptr = preload_search_by_name(filename);
438 if (modptr == NULL)
439 return ENOENT;
440
441 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
442 baseptr = preload_search_info(modptr, MODINFO_ADDR);
443 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
444 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
445 if (type == NULL || strcmp(type, "elf module") != 0)
446 return (EFTYPE);
447 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
448 return (EINVAL);
449
450 lf = linker_make_file(filename, &link_elf_class);
451 if (lf == NULL) {
452 return ENOMEM;
453 }
454
455 ef = (elf_file_t) lf;
456 ef->preloaded = 1;
457 ef->modptr = modptr;
458 ef->address = *(caddr_t *)baseptr;
459#ifdef SPARSE_MAPPING
460 ef->object = 0;
461#endif
462 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
463 ef->dynamic = (Elf_Dyn *)dp;
464 lf->address = ef->address;
465 lf->size = *(size_t *)sizeptr;
466
467 error = parse_dynamic(ef);
468 if (error) {
469 linker_file_unload(lf);
470 return error;
471 }
472 *result = lf;
473 return (0);
474}
475
476static int
477link_elf_link_preload_finish(linker_file_t lf)
478{
479 elf_file_t ef;
480 int error;
481#ifdef DDB
482 char *newfilename;
483#endif
484
485 ef = (elf_file_t) lf;
486#if 0 /* this will be more trouble than it's worth for now */
487 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
488 if (dp->d_tag != DT_NEEDED)
489 continue;
490 modname = ef->strtab + dp->d_un.d_val;
491 error = linker_load_module(modname, lf);
492 if (error)
493 goto out;
494 }
495#endif
496 error = relocate_file(ef);
497 if (error)
498 return error;
499 (void)link_elf_preload_parse_symbols(ef);
500
501#ifdef DDB
502 GDB_STATE(RT_ADD);
503 ef->gdb.l_addr = lf->address;
504 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
505 strcpy(newfilename, lf->filename);
506 ef->gdb.l_name = newfilename;
507 ef->gdb.l_ld = ef->dynamic;
508 link_elf_add_gdb(&ef->gdb);
509 GDB_STATE(RT_CONSISTENT);
510#endif
511
512 return (0);
513}
514
515static int
516link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* result)
517{
518 struct nameidata nd;
519 struct thread* td = curthread; /* XXX */
520 struct proc* p = td->td_proc; /* XXX */
521 Elf_Ehdr *hdr;
522 caddr_t firstpage;
523 int nbytes, i;
524 Elf_Phdr *phdr;
525 Elf_Phdr *phlimit;
526 Elf_Phdr *segs[2];
527 int nsegs;
528 Elf_Phdr *phdyn;
529 Elf_Phdr *phphdr;
530 caddr_t mapbase;
531 size_t mapsize;
532 Elf_Off base_offset;
533 Elf_Addr base_vaddr;
534 Elf_Addr base_vlimit;
535 int error = 0;
536 int resid, flags;
537 elf_file_t ef;
538 linker_file_t lf;
539 Elf_Shdr *shdr;
540 int symtabindex;
541 int symstrindex;
542 int symcnt;
543 int strcnt;
544#ifdef DDB
545 char *newfilename;
546#endif
547
548 GIANT_REQUIRED;
549
550 shdr = NULL;
551 lf = NULL;
552
553 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
554 flags = FREAD;
555 error = vn_open(&nd, &flags, 0);
556 if (error)
557 return error;
558 NDFREE(&nd, NDF_ONLY_PNBUF);
559
560 /*
561 * Read the elf header from the file.
562 */
563 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
564 if (firstpage == NULL) {
565 error = ENOMEM;
566 goto out;
567 }
568 hdr = (Elf_Ehdr *)firstpage;
569 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
570 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
571 nbytes = PAGE_SIZE - resid;
572 if (error)
573 goto out;
574
575 if (!IS_ELF(*hdr)) {
576 error = ENOEXEC;
577 goto out;
578 }
579
580 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
581 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
582 link_elf_error("Unsupported file layout");
583 error = ENOEXEC;
584 goto out;
585 }
586 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
587 || hdr->e_version != EV_CURRENT) {
588 link_elf_error("Unsupported file version");
589 error = ENOEXEC;
590 goto out;
591 }
592 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
593 link_elf_error("Unsupported file type");
594 error = ENOEXEC;
595 goto out;
596 }
597 if (hdr->e_machine != ELF_TARG_MACH) {
598 link_elf_error("Unsupported machine");
599 error = ENOEXEC;
600 goto out;
601 }
602
603 /*
604 * We rely on the program header being in the first page. This is
605 * not strictly required by the ABI specification, but it seems to
606 * always true in practice. And, it simplifies things considerably.
607 */
608 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
609 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
610 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
611 link_elf_error("Unreadable program headers");
612
613 /*
614 * Scan the program header entries, and save key information.
615 *
616 * We rely on there being exactly two load segments, text and data,
617 * in that order.
618 */
619 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
620 phlimit = phdr + hdr->e_phnum;
621 nsegs = 0;
622 phdyn = NULL;
623 phphdr = NULL;
624 while (phdr < phlimit) {
625 switch (phdr->p_type) {
626
627 case PT_LOAD:
628 if (nsegs == 2) {
629 link_elf_error("Too many sections");
630 error = ENOEXEC;
631 goto out;
632 }
633 segs[nsegs] = phdr;
634 ++nsegs;
635 break;
636
637 case PT_PHDR:
638 phphdr = phdr;
639 break;
640
641 case PT_DYNAMIC:
642 phdyn = phdr;
643 break;
644
645 case PT_INTERP:
646 link_elf_error("Unsupported file type");
647 error = ENOEXEC;
648 goto out;
649 }
650
651 ++phdr;
652 }
653 if (phdyn == NULL) {
654 link_elf_error("Object is not dynamically-linked");
655 error = ENOEXEC;
656 goto out;
657 }
658
659 /*
660 * Allocate the entire address space of the object, to stake out our
661 * contiguous region, and to establish the base address for relocation.
662 */
663 base_offset = trunc_page(segs[0]->p_offset);
664 base_vaddr = trunc_page(segs[0]->p_vaddr);
665 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
666 mapsize = base_vlimit - base_vaddr;
667
668 lf = linker_make_file(filename, &link_elf_class);
669 if (!lf) {
670 error = ENOMEM;
671 goto out;
672 }
673
674 ef = (elf_file_t) lf;
675#ifdef SPARSE_MAPPING
676 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
677 if (ef->object == NULL) {
678 free(ef, M_LINKER);
679 error = ENOMEM;
680 goto out;
681 }
682 vm_object_reference(ef->object);
683 ef->address = (caddr_t) vm_map_min(kernel_map);
684 error = vm_map_find(kernel_map, ef->object, 0,
685 (vm_offset_t *) &ef->address,
686 mapsize, 1,
687 VM_PROT_ALL, VM_PROT_ALL, 0);
688 if (error) {
689 vm_object_deallocate(ef->object);
690 ef->object = 0;
691 goto out;
692 }
693#else
694 ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
695 if (!ef->address) {
696 error = ENOMEM;
697 goto out;
698 }
699#endif
700 mapbase = ef->address;
701
702 /*
703 * Read the text and data sections and zero the bss.
704 */
705 for (i = 0; i < 2; i++) {
706 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
707 error = vn_rdwr(UIO_READ, nd.ni_vp,
708 segbase, segs[i]->p_filesz, segs[i]->p_offset,
709 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
710 if (error) {
711 goto out;
712 }
713 bzero(segbase + segs[i]->p_filesz,
714 segs[i]->p_memsz - segs[i]->p_filesz);
715
716#ifdef SPARSE_MAPPING
717 /*
718 * Wire down the pages
719 */
720 vm_map_pageable(kernel_map,
721 (vm_offset_t) segbase,
722 (vm_offset_t) segbase + segs[i]->p_memsz,
723 FALSE);
724#endif
725 }
726
727#ifdef GPROF
728 /* Update profiling information with the new text segment. */
729 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
730 segs[0]->p_memsz));
731#endif
732
733 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
734
735 lf->address = ef->address;
736 lf->size = mapsize;
737
738 error = parse_dynamic(ef);
739 if (error)
740 goto out;
741 error = linker_load_dependancies(lf);
742 if (error)
743 goto out;
744#if 0 /* this will be more trouble than it's worth for now */
745 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
746 if (dp->d_tag != DT_NEEDED)
747 continue;
748 modname = ef->strtab + dp->d_un.d_val;
749 error = linker_load_module(modname, lf);
750 if (error)
751 goto out;
752 }
753#endif
754 error = relocate_file(ef);
755 if (error)
756 goto out;
757
758 /* Try and load the symbol table if it's present. (you can strip it!) */
759 nbytes = hdr->e_shnum * hdr->e_shentsize;
760 if (nbytes == 0 || hdr->e_shoff == 0)
761 goto nosyms;
762 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
763 if (shdr == NULL) {
764 error = ENOMEM;
765 goto out;
766 }
767 error = vn_rdwr(UIO_READ, nd.ni_vp,
768 (caddr_t)shdr, nbytes, hdr->e_shoff,
769 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
770 if (error)
771 goto out;
772 symtabindex = -1;
773 symstrindex = -1;
774 for (i = 0; i < hdr->e_shnum; i++) {
775 if (shdr[i].sh_type == SHT_SYMTAB) {
776 symtabindex = i;
777 symstrindex = shdr[i].sh_link;
778 }
779 }
780 if (symtabindex < 0 || symstrindex < 0)
781 goto nosyms;
782
783 symcnt = shdr[symtabindex].sh_size;
784 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
785 strcnt = shdr[symstrindex].sh_size;
786 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
787
788 if (ef->symbase == NULL || ef->strbase == NULL) {
789 error = ENOMEM;
790 goto out;
791 }
792 error = vn_rdwr(UIO_READ, nd.ni_vp,
793 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
794 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
795 if (error)
796 goto out;
797 error = vn_rdwr(UIO_READ, nd.ni_vp,
798 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
799 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
800 if (error)
801 goto out;
802
803 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
804 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
805 ef->ddbstrcnt = strcnt;
806 ef->ddbstrtab = ef->strbase;
807
808#ifdef DDB
809 GDB_STATE(RT_ADD);
810 ef->gdb.l_addr = lf->address;
811 newfilename = malloc(strlen(filename) + 1, M_LINKER, M_WAITOK);
812 strcpy(newfilename, filename);
813 ef->gdb.l_name = (const char *)newfilename;
814 ef->gdb.l_ld = ef->dynamic;
815 link_elf_add_gdb(&ef->gdb);
816 GDB_STATE(RT_CONSISTENT);
817#endif
818
819nosyms:
820
821 *result = lf;
822
823out:
824 if (error && lf)
825 linker_file_unload(lf);
826 if (shdr)
827 free(shdr, M_LINKER);
828 if (firstpage)
829 free(firstpage, M_LINKER);
830 VOP_UNLOCK(nd.ni_vp, 0, td);
831 vn_close(nd.ni_vp, FREAD, p->p_ucred, td);
832
833 return error;
834}
835
836static void
837link_elf_unload_file(linker_file_t file)
838{
839 elf_file_t ef = (elf_file_t) file;
840
841#ifdef DDB
842 if (ef->gdb.l_ld) {
843 GDB_STATE(RT_DELETE);
844 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
845 link_elf_delete_gdb(&ef->gdb);
846 GDB_STATE(RT_CONSISTENT);
847 }
848#endif
849
850 if (ef->preloaded) {
851 link_elf_unload_preload(file);
852 return;
853 }
854#ifdef SPARSE_MAPPING
855 if (ef->object) {
856 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
857 (vm_offset_t) ef->address
858 + (ef->object->size << PAGE_SHIFT));
859 vm_object_deallocate(ef->object);
860 }
861#else
862 if (ef->address)
863 free(ef->address, M_LINKER);
864#endif
865 if (ef->symbase)
866 free(ef->symbase, M_LINKER);
867 if (ef->strbase)
868 free(ef->strbase, M_LINKER);
869}
870
871static void
872link_elf_unload_preload(linker_file_t file)
873{
874 if (file->filename)
875 preload_delete_name(file->filename);
876}
877
878static const char *
879symbol_name(elf_file_t ef, Elf_Word r_info)
880{
881 const Elf_Sym *ref;
882
883 if (ELF_R_SYM(r_info)) {
884 ref = ef->symtab + ELF_R_SYM(r_info);
885 return ef->strtab + ref->st_name;
886 } else
887 return NULL;
888}
889
890static int
891relocate_file(elf_file_t ef)
892{
893 const Elf_Rel *rellim;
894 const Elf_Rel *rel;
895 const Elf_Rela *relalim;
896 const Elf_Rela *rela;
897 const char *symname;
898
899 /* Perform relocations without addend if there are any: */
900 rel = ef->rel;
901 if (rel) {
902 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
903 while (rel < rellim) {
904 symname = symbol_name(ef, rel->r_info);
905 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) {
906 printf("link_elf: symbol %s undefined\n", symname);
907 return ENOENT;
908 }
909 rel++;
910 }
911 }
912
913 /* Perform relocations with addend if there are any: */
914 rela = ef->rela;
915 if (rela) {
916 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
917 while (rela < relalim) {
918 symname = symbol_name(ef, rela->r_info);
919 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) {
920 printf("link_elf: symbol %s undefined\n", symname);
921 return ENOENT;
922 }
923 rela++;
924 }
925 }
926
927 /* Perform PLT relocations without addend if there are any: */
928 rel = ef->pltrel;
929 if (rel) {
930 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
931 while (rel < rellim) {
932 symname = symbol_name(ef, rel->r_info);
933 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) {
934 printf("link_elf: symbol %s undefined\n", symname);
935 return ENOENT;
936 }
937 rel++;
938 }
939 }
940
941 /* Perform relocations with addend if there are any: */
942 rela = ef->pltrela;
943 if (rela) {
944 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
945 while (rela < relalim) {
946 symname = symbol_name(ef, rela->r_info);
947 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) {
948 printf("link_elf: symbol %s undefined\n", symname);
949 return ENOENT;
950 }
951 rela++;
952 }
953 }
954
955 return 0;
956}
957
958/*
959 * Hash function for symbol table lookup. Don't even think about changing
960 * this. It is specified by the System V ABI.
961 */
962static unsigned long
963elf_hash(const char *name)
964{
965 const unsigned char *p = (const unsigned char *) name;
966 unsigned long h = 0;
967 unsigned long g;
968
969 while (*p != '\0') {
970 h = (h << 4) + *p++;
971 if ((g = h & 0xf0000000) != 0)
972 h ^= g >> 24;
973 h &= ~g;
974 }
975 return h;
976}
977
978int
979link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
980{
981 elf_file_t ef = (elf_file_t) lf;
982 unsigned long symnum;
983 const Elf_Sym* symp;
984 const char *strp;
985 unsigned long hash;
986 int i;
987
988 /* First, search hashed global symbols */
989 hash = elf_hash(name);
990 symnum = ef->buckets[hash % ef->nbuckets];
991
992 while (symnum != STN_UNDEF) {
993 if (symnum >= ef->nchains) {
994 printf("link_elf_lookup_symbol: corrupt symbol table\n");
995 return ENOENT;
996 }
997
998 symp = ef->symtab + symnum;
999 if (symp->st_name == 0) {
1000 printf("link_elf_lookup_symbol: corrupt symbol table\n");
1001 return ENOENT;
1002 }
1003
1004 strp = ef->strtab + symp->st_name;
1005
1006 if (strcmp(name, strp) == 0) {
1007 if (symp->st_shndx != SHN_UNDEF ||
1008 (symp->st_value != 0 &&
1009 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1010 *sym = (c_linker_sym_t) symp;
1011 return 0;
1012 } else
1013 return ENOENT;
1014 }
1015
1016 symnum = ef->chains[symnum];
1017 }
1018
1019 /* If we have not found it, look at the full table (if loaded) */
1020 if (ef->symtab == ef->ddbsymtab)
1021 return ENOENT;
1022
1023 /* Exhaustive search */
1024 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1025 strp = ef->ddbstrtab + symp->st_name;
1026 if (strcmp(name, strp) == 0) {
1027 if (symp->st_shndx != SHN_UNDEF ||
1028 (symp->st_value != 0 &&
1029 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1030 *sym = (c_linker_sym_t) symp;
1031 return 0;
1032 } else
1033 return ENOENT;
1034 }
1035 }
1036
1037 return ENOENT;
1038}
1039
1040static int
1041link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
1042{
1043 elf_file_t ef = (elf_file_t) lf;
1044 const Elf_Sym* es = (const Elf_Sym*) sym;
1045
1046 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) {
1047 symval->name = ef->strtab + es->st_name;
1048 symval->value = (caddr_t) ef->address + es->st_value;
1049 symval->size = es->st_size;
1050 return 0;
1051 }
1052 if (ef->symtab == ef->ddbsymtab)
1053 return ENOENT;
1054 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) {
1055 symval->name = ef->ddbstrtab + es->st_name;
1056 symval->value = (caddr_t) ef->address + es->st_value;
1057 symval->size = es->st_size;
1058 return 0;
1059 }
1060 return ENOENT;
1061}
1062
1063static int
1064link_elf_search_symbol(linker_file_t lf, caddr_t value,
1065 c_linker_sym_t* sym, long* diffp)
1066{
1067 elf_file_t ef = (elf_file_t) lf;
1068 u_long off = (uintptr_t) (void *) value;
1069 u_long diff = off;
1070 u_long st_value;
1071 const Elf_Sym* es;
1072 const Elf_Sym* best = 0;
1073 int i;
1074
1075 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1076 if (es->st_name == 0)
1077 continue;
1078 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1079 if (off >= st_value) {
1080 if (off - st_value < diff) {
1081 diff = off - st_value;
1082 best = es;
1083 if (diff == 0)
1084 break;
1085 } else if (off - st_value == diff) {
1086 best = es;
1087 }
1088 }
1089 }
1090 if (best == 0)
1091 *diffp = off;
1092 else
1093 *diffp = diff;
1094 *sym = (c_linker_sym_t) best;
1095
1096 return 0;
1097}
1098
1099/*
1100 * Look up a linker set on an ELF system.
1101 */
1102static int
1103link_elf_lookup_set(linker_file_t lf, const char *name,
1104 void ***startp, void ***stopp, int *countp)
1105{
1106 c_linker_sym_t sym;
1107 linker_symval_t symval;
1108 char *setsym;
1109 void **start, **stop;
1110 int len, error = 0, count;
1111
1112 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1113 setsym = malloc(len, M_LINKER, M_WAITOK);
1114 if (setsym == NULL)
1115 return ENOMEM;
1116
1117 /* get address of first entry */
1118 snprintf(setsym, len, "%s%s", "__start_set_", name);
1119 error = link_elf_lookup_symbol(lf, setsym, &sym);
1120 if (error)
1121 goto out;
1122 link_elf_symbol_values(lf, sym, &symval);
1123 if (symval.value == 0) {
1124 error = ESRCH;
1125 goto out;
1126 }
1127 start = (void **)symval.value;
1128
1129 /* get address of last entry */
1130 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1131 error = link_elf_lookup_symbol(lf, setsym, &sym);
1132 if (error)
1133 goto out;
1134 link_elf_symbol_values(lf, sym, &symval);
1135 if (symval.value == 0) {
1136 error = ESRCH;
1137 goto out;
1138 }
1139 stop = (void **)symval.value;
1140
1141 /* and the number of entries */
1142 count = stop - start;
1143
1144 /* and copy out */
1145 if (startp)
1146 *startp = start;
1147 if (stopp)
1148 *stopp = stop;
1149 if (countp)
1150 *countp = count;
1151
1152out:
1153 free(setsym, M_LINKER);
1154 return error;
1155}
1156
1157static int
1158link_elf_each_function_name(linker_file_t file,
1159 int (*callback)(const char *, void *), void *opaque) {
1160 elf_file_t ef = (elf_file_t)file;
1161 const Elf_Sym* symp;
1162 int i, error;
1163
1164 /* Exhaustive search */
1165 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1166 if (symp->st_value != 0 &&
1167 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1168 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1169 if (error)
1170 return (error);
1171 }
1172 }
1173 return (0);
1174}
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 * $FreeBSD: head/sys/kern/link_elf_obj.c 85736 2001-10-30 15:21:45Z green $
27 */
28
29#include "opt_ddb.h"
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/kernel.h>
34#include <sys/lock.h>
35#include <sys/malloc.h>
36#include <sys/mutex.h>
37#include <sys/proc.h>
38#include <sys/namei.h>
39#include <sys/fcntl.h>
40#include <sys/vnode.h>
41#include <sys/linker.h>
42
43#include <machine/elf.h>
44#ifdef GPROF
45#include <machine/profile.h>
46#endif
47
48#include <vm/vm.h>
49#include <vm/vm_param.h>
50#ifdef SPARSE_MAPPING
51#include <vm/vm_object.h>
52#include <vm/vm_kern.h>
53#include <vm/vm_extern.h>
54#endif
55#include <vm/pmap.h>
56#include <vm/vm_map.h>
57
58#ifdef __AOUT__
59#include <nlist.h>
60#endif
61#include <link.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_preload(linker_class_t cls,
103 const char*, linker_file_t*);
104static int link_elf_link_preload_finish(linker_file_t);
105static int link_elf_load_file(linker_class_t, const char*, linker_file_t*);
106static int link_elf_lookup_symbol(linker_file_t, const char*,
107 c_linker_sym_t*);
108static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
109static int link_elf_search_symbol(linker_file_t, caddr_t value,
110 c_linker_sym_t* sym, long* diffp);
111
112static void link_elf_unload_file(linker_file_t);
113static void link_elf_unload_preload(linker_file_t);
114static int link_elf_lookup_set(linker_file_t, const char *,
115 void ***, void ***, int *);
116static int link_elf_each_function_name(linker_file_t,
117 int (*)(const char *, void *),
118 void *);
119
120static kobj_method_t link_elf_methods[] = {
121 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
122 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
123 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
124 KOBJMETHOD(linker_unload, link_elf_unload_file),
125 KOBJMETHOD(linker_load_file, link_elf_load_file),
126 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
127 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
128 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
129 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
130 { 0, 0 }
131};
132
133static struct linker_class link_elf_class = {
134#if ELF_TARG_CLASS == ELFCLASS32
135 "elf32",
136#else
137 "elf64",
138#endif
139 link_elf_methods, sizeof(struct elf_file)
140};
141
142static int parse_dynamic(elf_file_t ef);
143static int relocate_file(elf_file_t ef);
144static int link_elf_preload_parse_symbols(elf_file_t ef);
145
146#ifdef DDB
147static void r_debug_state(struct r_debug *dummy_one,
148 struct link_map *dummy_two);
149
150/*
151 * A list of loaded modules for GDB to use for loading symbols.
152 */
153struct r_debug r_debug;
154
155#define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL);
156
157/*
158 * Function for the debugger to set a breakpoint on to gain control.
159 */
160void
161r_debug_state(struct r_debug *dummy_one __unused,
162 struct link_map *dummy_two __unused)
163{
164}
165
166#endif
167
168/*
169 * The kernel symbol table starts here.
170 */
171extern struct _dynamic _DYNAMIC;
172
173static void
174link_elf_init(void* arg)
175{
176#ifdef __ELF__
177 Elf_Dyn *dp;
178 caddr_t modptr, baseptr, sizeptr;
179 elf_file_t ef;
180 char *modname;
181#ifdef DDB
182 char *newfilename;
183#endif
184#endif
185
186 linker_add_class(&link_elf_class);
187
188#ifdef __ELF__
189 dp = (Elf_Dyn*) &_DYNAMIC;
190 modname = NULL;
191 modptr = preload_search_by_type("elf kernel");
192 if (modptr)
193 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
194 if (modname == NULL)
195 modname = "kernel";
196 linker_kernel_file = linker_make_file(modname, &link_elf_class);
197 if (linker_kernel_file == NULL)
198 panic("link_elf_init: Can't create linker structures for kernel");
199
200 ef = (elf_file_t) linker_kernel_file;
201 ef->preloaded = 1;
202 ef->address = 0;
203#ifdef SPARSE_MAPPING
204 ef->object = 0;
205#endif
206 ef->dynamic = dp;
207
208 if (dp)
209 parse_dynamic(ef);
210 linker_kernel_file->address = (caddr_t) KERNBASE;
211 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
212
213 if (modptr) {
214 ef->modptr = modptr;
215 baseptr = preload_search_info(modptr, MODINFO_ADDR);
216 if (baseptr)
217 linker_kernel_file->address = *(caddr_t *)baseptr;
218 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
219 if (sizeptr)
220 linker_kernel_file->size = *(size_t *)sizeptr;
221 }
222 (void)link_elf_preload_parse_symbols(ef);
223
224#ifdef DDB
225 ef->gdb.l_addr = linker_kernel_file->address;
226 newfilename = malloc(strlen(modname) + 1, M_LINKER, M_WAITOK);
227 strcpy(newfilename, modname);
228 ef->gdb.l_name = newfilename;
229 ef->gdb.l_ld = dp;
230 ef->gdb.l_prev = 0;
231 ef->gdb.l_next = 0;
232
233 r_debug.r_map = &ef->gdb;
234 r_debug.r_brk = r_debug_state;
235 r_debug.r_state = RT_CONSISTENT;
236
237 r_debug_state(NULL, NULL); /* say hello to gdb! */
238#endif
239
240#endif
241}
242
243SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
244
245static int
246link_elf_preload_parse_symbols(elf_file_t ef)
247{
248 caddr_t pointer;
249 caddr_t ssym, esym, base;
250 caddr_t strtab;
251 int strcnt;
252 Elf_Sym* symtab;
253 int symcnt;
254
255 if (ef->modptr == NULL)
256 return 0;
257 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
258 if (pointer == NULL)
259 return 0;
260 ssym = *(caddr_t *)pointer;
261 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
262 if (pointer == NULL)
263 return 0;
264 esym = *(caddr_t *)pointer;
265
266 base = ssym;
267
268 symcnt = *(long *)base;
269 base += sizeof(long);
270 symtab = (Elf_Sym *)base;
271 base += roundup(symcnt, sizeof(long));
272
273 if (base > esym || base < ssym) {
274 printf("Symbols are corrupt!\n");
275 return EINVAL;
276 }
277
278 strcnt = *(long *)base;
279 base += sizeof(long);
280 strtab = base;
281 base += roundup(strcnt, sizeof(long));
282
283 if (base > esym || base < ssym) {
284 printf("Symbols are corrupt!\n");
285 return EINVAL;
286 }
287
288 ef->ddbsymtab = symtab;
289 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
290 ef->ddbstrtab = strtab;
291 ef->ddbstrcnt = strcnt;
292
293 return 0;
294}
295
296static int
297parse_dynamic(elf_file_t ef)
298{
299 Elf_Dyn *dp;
300 int plttype = DT_REL;
301
302 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
303 switch (dp->d_tag) {
304 case DT_HASH:
305 {
306 /* From src/libexec/rtld-elf/rtld.c */
307 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
308 (ef->address + dp->d_un.d_ptr);
309 ef->nbuckets = hashtab[0];
310 ef->nchains = hashtab[1];
311 ef->buckets = hashtab + 2;
312 ef->chains = ef->buckets + ef->nbuckets;
313 break;
314 }
315 case DT_STRTAB:
316 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
317 break;
318 case DT_STRSZ:
319 ef->strsz = dp->d_un.d_val;
320 break;
321 case DT_SYMTAB:
322 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
323 break;
324 case DT_SYMENT:
325 if (dp->d_un.d_val != sizeof(Elf_Sym))
326 return ENOEXEC;
327 break;
328 case DT_PLTGOT:
329 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
330 break;
331 case DT_REL:
332 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
333 break;
334 case DT_RELSZ:
335 ef->relsize = dp->d_un.d_val;
336 break;
337 case DT_RELENT:
338 if (dp->d_un.d_val != sizeof(Elf_Rel))
339 return ENOEXEC;
340 break;
341 case DT_JMPREL:
342 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
343 break;
344 case DT_PLTRELSZ:
345 ef->pltrelsize = dp->d_un.d_val;
346 break;
347 case DT_RELA:
348 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
349 break;
350 case DT_RELASZ:
351 ef->relasize = dp->d_un.d_val;
352 break;
353 case DT_RELAENT:
354 if (dp->d_un.d_val != sizeof(Elf_Rela))
355 return ENOEXEC;
356 break;
357 case DT_PLTREL:
358 plttype = dp->d_un.d_val;
359 if (plttype != DT_REL && plttype != DT_RELA)
360 return ENOEXEC;
361 break;
362#ifdef DDB
363 case DT_DEBUG:
364 dp->d_un.d_ptr = (Elf_Addr) &r_debug;
365 break;
366#endif
367 }
368 }
369
370 if (plttype == DT_RELA) {
371 ef->pltrela = (const Elf_Rela *) ef->pltrel;
372 ef->pltrel = NULL;
373 ef->pltrelasize = ef->pltrelsize;
374 ef->pltrelsize = 0;
375 }
376
377 ef->ddbsymtab = ef->symtab;
378 ef->ddbsymcnt = ef->nchains;
379 ef->ddbstrtab = ef->strtab;
380 ef->ddbstrcnt = ef->strsz;
381
382 return 0;
383}
384
385static void
386link_elf_error(const char *s)
387{
388 printf("kldload: %s\n", s);
389}
390
391#ifdef DDB
392
393static void
394link_elf_add_gdb(struct link_map *l)
395{
396 struct link_map *prev;
397
398 /*
399 * Scan to the end of the list.
400 */
401 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
402 ;
403
404 /* Link in the new entry. */
405 l->l_prev = prev;
406 l->l_next = prev->l_next;
407 prev->l_next = l;
408}
409
410static void
411link_elf_delete_gdb(struct link_map *l)
412{
413 if (l->l_prev == NULL) {
414 if ((r_debug.r_map = l->l_next) != NULL)
415 l->l_next->l_prev = NULL;
416 return;
417 }
418
419 if ((l->l_prev->l_next = l->l_next) != NULL)
420 l->l_next->l_prev = l->l_prev;
421}
422
423#endif /* DDB */
424
425static int
426link_elf_link_preload(linker_class_t cls,
427 const char* filename, linker_file_t *result)
428{
429 caddr_t modptr, baseptr, sizeptr, dynptr;
430 char *type;
431 elf_file_t ef;
432 linker_file_t lf;
433 int error;
434 vm_offset_t dp;
435
436 /* Look to see if we have the file preloaded */
437 modptr = preload_search_by_name(filename);
438 if (modptr == NULL)
439 return ENOENT;
440
441 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
442 baseptr = preload_search_info(modptr, MODINFO_ADDR);
443 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
444 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
445 if (type == NULL || strcmp(type, "elf module") != 0)
446 return (EFTYPE);
447 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
448 return (EINVAL);
449
450 lf = linker_make_file(filename, &link_elf_class);
451 if (lf == NULL) {
452 return ENOMEM;
453 }
454
455 ef = (elf_file_t) lf;
456 ef->preloaded = 1;
457 ef->modptr = modptr;
458 ef->address = *(caddr_t *)baseptr;
459#ifdef SPARSE_MAPPING
460 ef->object = 0;
461#endif
462 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
463 ef->dynamic = (Elf_Dyn *)dp;
464 lf->address = ef->address;
465 lf->size = *(size_t *)sizeptr;
466
467 error = parse_dynamic(ef);
468 if (error) {
469 linker_file_unload(lf);
470 return error;
471 }
472 *result = lf;
473 return (0);
474}
475
476static int
477link_elf_link_preload_finish(linker_file_t lf)
478{
479 elf_file_t ef;
480 int error;
481#ifdef DDB
482 char *newfilename;
483#endif
484
485 ef = (elf_file_t) lf;
486#if 0 /* this will be more trouble than it's worth for now */
487 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
488 if (dp->d_tag != DT_NEEDED)
489 continue;
490 modname = ef->strtab + dp->d_un.d_val;
491 error = linker_load_module(modname, lf);
492 if (error)
493 goto out;
494 }
495#endif
496 error = relocate_file(ef);
497 if (error)
498 return error;
499 (void)link_elf_preload_parse_symbols(ef);
500
501#ifdef DDB
502 GDB_STATE(RT_ADD);
503 ef->gdb.l_addr = lf->address;
504 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
505 strcpy(newfilename, lf->filename);
506 ef->gdb.l_name = newfilename;
507 ef->gdb.l_ld = ef->dynamic;
508 link_elf_add_gdb(&ef->gdb);
509 GDB_STATE(RT_CONSISTENT);
510#endif
511
512 return (0);
513}
514
515static int
516link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* result)
517{
518 struct nameidata nd;
519 struct thread* td = curthread; /* XXX */
520 struct proc* p = td->td_proc; /* XXX */
521 Elf_Ehdr *hdr;
522 caddr_t firstpage;
523 int nbytes, i;
524 Elf_Phdr *phdr;
525 Elf_Phdr *phlimit;
526 Elf_Phdr *segs[2];
527 int nsegs;
528 Elf_Phdr *phdyn;
529 Elf_Phdr *phphdr;
530 caddr_t mapbase;
531 size_t mapsize;
532 Elf_Off base_offset;
533 Elf_Addr base_vaddr;
534 Elf_Addr base_vlimit;
535 int error = 0;
536 int resid, flags;
537 elf_file_t ef;
538 linker_file_t lf;
539 Elf_Shdr *shdr;
540 int symtabindex;
541 int symstrindex;
542 int symcnt;
543 int strcnt;
544#ifdef DDB
545 char *newfilename;
546#endif
547
548 GIANT_REQUIRED;
549
550 shdr = NULL;
551 lf = NULL;
552
553 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
554 flags = FREAD;
555 error = vn_open(&nd, &flags, 0);
556 if (error)
557 return error;
558 NDFREE(&nd, NDF_ONLY_PNBUF);
559
560 /*
561 * Read the elf header from the file.
562 */
563 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
564 if (firstpage == NULL) {
565 error = ENOMEM;
566 goto out;
567 }
568 hdr = (Elf_Ehdr *)firstpage;
569 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
570 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
571 nbytes = PAGE_SIZE - resid;
572 if (error)
573 goto out;
574
575 if (!IS_ELF(*hdr)) {
576 error = ENOEXEC;
577 goto out;
578 }
579
580 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
581 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
582 link_elf_error("Unsupported file layout");
583 error = ENOEXEC;
584 goto out;
585 }
586 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
587 || hdr->e_version != EV_CURRENT) {
588 link_elf_error("Unsupported file version");
589 error = ENOEXEC;
590 goto out;
591 }
592 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
593 link_elf_error("Unsupported file type");
594 error = ENOEXEC;
595 goto out;
596 }
597 if (hdr->e_machine != ELF_TARG_MACH) {
598 link_elf_error("Unsupported machine");
599 error = ENOEXEC;
600 goto out;
601 }
602
603 /*
604 * We rely on the program header being in the first page. This is
605 * not strictly required by the ABI specification, but it seems to
606 * always true in practice. And, it simplifies things considerably.
607 */
608 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
609 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
610 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
611 link_elf_error("Unreadable program headers");
612
613 /*
614 * Scan the program header entries, and save key information.
615 *
616 * We rely on there being exactly two load segments, text and data,
617 * in that order.
618 */
619 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
620 phlimit = phdr + hdr->e_phnum;
621 nsegs = 0;
622 phdyn = NULL;
623 phphdr = NULL;
624 while (phdr < phlimit) {
625 switch (phdr->p_type) {
626
627 case PT_LOAD:
628 if (nsegs == 2) {
629 link_elf_error("Too many sections");
630 error = ENOEXEC;
631 goto out;
632 }
633 segs[nsegs] = phdr;
634 ++nsegs;
635 break;
636
637 case PT_PHDR:
638 phphdr = phdr;
639 break;
640
641 case PT_DYNAMIC:
642 phdyn = phdr;
643 break;
644
645 case PT_INTERP:
646 link_elf_error("Unsupported file type");
647 error = ENOEXEC;
648 goto out;
649 }
650
651 ++phdr;
652 }
653 if (phdyn == NULL) {
654 link_elf_error("Object is not dynamically-linked");
655 error = ENOEXEC;
656 goto out;
657 }
658
659 /*
660 * Allocate the entire address space of the object, to stake out our
661 * contiguous region, and to establish the base address for relocation.
662 */
663 base_offset = trunc_page(segs[0]->p_offset);
664 base_vaddr = trunc_page(segs[0]->p_vaddr);
665 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
666 mapsize = base_vlimit - base_vaddr;
667
668 lf = linker_make_file(filename, &link_elf_class);
669 if (!lf) {
670 error = ENOMEM;
671 goto out;
672 }
673
674 ef = (elf_file_t) lf;
675#ifdef SPARSE_MAPPING
676 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
677 if (ef->object == NULL) {
678 free(ef, M_LINKER);
679 error = ENOMEM;
680 goto out;
681 }
682 vm_object_reference(ef->object);
683 ef->address = (caddr_t) vm_map_min(kernel_map);
684 error = vm_map_find(kernel_map, ef->object, 0,
685 (vm_offset_t *) &ef->address,
686 mapsize, 1,
687 VM_PROT_ALL, VM_PROT_ALL, 0);
688 if (error) {
689 vm_object_deallocate(ef->object);
690 ef->object = 0;
691 goto out;
692 }
693#else
694 ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
695 if (!ef->address) {
696 error = ENOMEM;
697 goto out;
698 }
699#endif
700 mapbase = ef->address;
701
702 /*
703 * Read the text and data sections and zero the bss.
704 */
705 for (i = 0; i < 2; i++) {
706 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
707 error = vn_rdwr(UIO_READ, nd.ni_vp,
708 segbase, segs[i]->p_filesz, segs[i]->p_offset,
709 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
710 if (error) {
711 goto out;
712 }
713 bzero(segbase + segs[i]->p_filesz,
714 segs[i]->p_memsz - segs[i]->p_filesz);
715
716#ifdef SPARSE_MAPPING
717 /*
718 * Wire down the pages
719 */
720 vm_map_pageable(kernel_map,
721 (vm_offset_t) segbase,
722 (vm_offset_t) segbase + segs[i]->p_memsz,
723 FALSE);
724#endif
725 }
726
727#ifdef GPROF
728 /* Update profiling information with the new text segment. */
729 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
730 segs[0]->p_memsz));
731#endif
732
733 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
734
735 lf->address = ef->address;
736 lf->size = mapsize;
737
738 error = parse_dynamic(ef);
739 if (error)
740 goto out;
741 error = linker_load_dependancies(lf);
742 if (error)
743 goto out;
744#if 0 /* this will be more trouble than it's worth for now */
745 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
746 if (dp->d_tag != DT_NEEDED)
747 continue;
748 modname = ef->strtab + dp->d_un.d_val;
749 error = linker_load_module(modname, lf);
750 if (error)
751 goto out;
752 }
753#endif
754 error = relocate_file(ef);
755 if (error)
756 goto out;
757
758 /* Try and load the symbol table if it's present. (you can strip it!) */
759 nbytes = hdr->e_shnum * hdr->e_shentsize;
760 if (nbytes == 0 || hdr->e_shoff == 0)
761 goto nosyms;
762 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
763 if (shdr == NULL) {
764 error = ENOMEM;
765 goto out;
766 }
767 error = vn_rdwr(UIO_READ, nd.ni_vp,
768 (caddr_t)shdr, nbytes, hdr->e_shoff,
769 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
770 if (error)
771 goto out;
772 symtabindex = -1;
773 symstrindex = -1;
774 for (i = 0; i < hdr->e_shnum; i++) {
775 if (shdr[i].sh_type == SHT_SYMTAB) {
776 symtabindex = i;
777 symstrindex = shdr[i].sh_link;
778 }
779 }
780 if (symtabindex < 0 || symstrindex < 0)
781 goto nosyms;
782
783 symcnt = shdr[symtabindex].sh_size;
784 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
785 strcnt = shdr[symstrindex].sh_size;
786 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
787
788 if (ef->symbase == NULL || ef->strbase == NULL) {
789 error = ENOMEM;
790 goto out;
791 }
792 error = vn_rdwr(UIO_READ, nd.ni_vp,
793 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
794 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
795 if (error)
796 goto out;
797 error = vn_rdwr(UIO_READ, nd.ni_vp,
798 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
799 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
800 if (error)
801 goto out;
802
803 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
804 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
805 ef->ddbstrcnt = strcnt;
806 ef->ddbstrtab = ef->strbase;
807
808#ifdef DDB
809 GDB_STATE(RT_ADD);
810 ef->gdb.l_addr = lf->address;
811 newfilename = malloc(strlen(filename) + 1, M_LINKER, M_WAITOK);
812 strcpy(newfilename, filename);
813 ef->gdb.l_name = (const char *)newfilename;
814 ef->gdb.l_ld = ef->dynamic;
815 link_elf_add_gdb(&ef->gdb);
816 GDB_STATE(RT_CONSISTENT);
817#endif
818
819nosyms:
820
821 *result = lf;
822
823out:
824 if (error && lf)
825 linker_file_unload(lf);
826 if (shdr)
827 free(shdr, M_LINKER);
828 if (firstpage)
829 free(firstpage, M_LINKER);
830 VOP_UNLOCK(nd.ni_vp, 0, td);
831 vn_close(nd.ni_vp, FREAD, p->p_ucred, td);
832
833 return error;
834}
835
836static void
837link_elf_unload_file(linker_file_t file)
838{
839 elf_file_t ef = (elf_file_t) file;
840
841#ifdef DDB
842 if (ef->gdb.l_ld) {
843 GDB_STATE(RT_DELETE);
844 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
845 link_elf_delete_gdb(&ef->gdb);
846 GDB_STATE(RT_CONSISTENT);
847 }
848#endif
849
850 if (ef->preloaded) {
851 link_elf_unload_preload(file);
852 return;
853 }
854#ifdef SPARSE_MAPPING
855 if (ef->object) {
856 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
857 (vm_offset_t) ef->address
858 + (ef->object->size << PAGE_SHIFT));
859 vm_object_deallocate(ef->object);
860 }
861#else
862 if (ef->address)
863 free(ef->address, M_LINKER);
864#endif
865 if (ef->symbase)
866 free(ef->symbase, M_LINKER);
867 if (ef->strbase)
868 free(ef->strbase, M_LINKER);
869}
870
871static void
872link_elf_unload_preload(linker_file_t file)
873{
874 if (file->filename)
875 preload_delete_name(file->filename);
876}
877
878static const char *
879symbol_name(elf_file_t ef, Elf_Word r_info)
880{
881 const Elf_Sym *ref;
882
883 if (ELF_R_SYM(r_info)) {
884 ref = ef->symtab + ELF_R_SYM(r_info);
885 return ef->strtab + ref->st_name;
886 } else
887 return NULL;
888}
889
890static int
891relocate_file(elf_file_t ef)
892{
893 const Elf_Rel *rellim;
894 const Elf_Rel *rel;
895 const Elf_Rela *relalim;
896 const Elf_Rela *rela;
897 const char *symname;
898
899 /* Perform relocations without addend if there are any: */
900 rel = ef->rel;
901 if (rel) {
902 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
903 while (rel < rellim) {
904 symname = symbol_name(ef, rel->r_info);
905 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) {
906 printf("link_elf: symbol %s undefined\n", symname);
907 return ENOENT;
908 }
909 rel++;
910 }
911 }
912
913 /* Perform relocations with addend if there are any: */
914 rela = ef->rela;
915 if (rela) {
916 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
917 while (rela < relalim) {
918 symname = symbol_name(ef, rela->r_info);
919 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) {
920 printf("link_elf: symbol %s undefined\n", symname);
921 return ENOENT;
922 }
923 rela++;
924 }
925 }
926
927 /* Perform PLT relocations without addend if there are any: */
928 rel = ef->pltrel;
929 if (rel) {
930 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
931 while (rel < rellim) {
932 symname = symbol_name(ef, rel->r_info);
933 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) {
934 printf("link_elf: symbol %s undefined\n", symname);
935 return ENOENT;
936 }
937 rel++;
938 }
939 }
940
941 /* Perform relocations with addend if there are any: */
942 rela = ef->pltrela;
943 if (rela) {
944 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
945 while (rela < relalim) {
946 symname = symbol_name(ef, rela->r_info);
947 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) {
948 printf("link_elf: symbol %s undefined\n", symname);
949 return ENOENT;
950 }
951 rela++;
952 }
953 }
954
955 return 0;
956}
957
958/*
959 * Hash function for symbol table lookup. Don't even think about changing
960 * this. It is specified by the System V ABI.
961 */
962static unsigned long
963elf_hash(const char *name)
964{
965 const unsigned char *p = (const unsigned char *) name;
966 unsigned long h = 0;
967 unsigned long g;
968
969 while (*p != '\0') {
970 h = (h << 4) + *p++;
971 if ((g = h & 0xf0000000) != 0)
972 h ^= g >> 24;
973 h &= ~g;
974 }
975 return h;
976}
977
978int
979link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
980{
981 elf_file_t ef = (elf_file_t) lf;
982 unsigned long symnum;
983 const Elf_Sym* symp;
984 const char *strp;
985 unsigned long hash;
986 int i;
987
988 /* First, search hashed global symbols */
989 hash = elf_hash(name);
990 symnum = ef->buckets[hash % ef->nbuckets];
991
992 while (symnum != STN_UNDEF) {
993 if (symnum >= ef->nchains) {
994 printf("link_elf_lookup_symbol: corrupt symbol table\n");
995 return ENOENT;
996 }
997
998 symp = ef->symtab + symnum;
999 if (symp->st_name == 0) {
1000 printf("link_elf_lookup_symbol: corrupt symbol table\n");
1001 return ENOENT;
1002 }
1003
1004 strp = ef->strtab + symp->st_name;
1005
1006 if (strcmp(name, strp) == 0) {
1007 if (symp->st_shndx != SHN_UNDEF ||
1008 (symp->st_value != 0 &&
1009 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1010 *sym = (c_linker_sym_t) symp;
1011 return 0;
1012 } else
1013 return ENOENT;
1014 }
1015
1016 symnum = ef->chains[symnum];
1017 }
1018
1019 /* If we have not found it, look at the full table (if loaded) */
1020 if (ef->symtab == ef->ddbsymtab)
1021 return ENOENT;
1022
1023 /* Exhaustive search */
1024 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1025 strp = ef->ddbstrtab + symp->st_name;
1026 if (strcmp(name, strp) == 0) {
1027 if (symp->st_shndx != SHN_UNDEF ||
1028 (symp->st_value != 0 &&
1029 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1030 *sym = (c_linker_sym_t) symp;
1031 return 0;
1032 } else
1033 return ENOENT;
1034 }
1035 }
1036
1037 return ENOENT;
1038}
1039
1040static int
1041link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
1042{
1043 elf_file_t ef = (elf_file_t) lf;
1044 const Elf_Sym* es = (const Elf_Sym*) sym;
1045
1046 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) {
1047 symval->name = ef->strtab + es->st_name;
1048 symval->value = (caddr_t) ef->address + es->st_value;
1049 symval->size = es->st_size;
1050 return 0;
1051 }
1052 if (ef->symtab == ef->ddbsymtab)
1053 return ENOENT;
1054 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) {
1055 symval->name = ef->ddbstrtab + es->st_name;
1056 symval->value = (caddr_t) ef->address + es->st_value;
1057 symval->size = es->st_size;
1058 return 0;
1059 }
1060 return ENOENT;
1061}
1062
1063static int
1064link_elf_search_symbol(linker_file_t lf, caddr_t value,
1065 c_linker_sym_t* sym, long* diffp)
1066{
1067 elf_file_t ef = (elf_file_t) lf;
1068 u_long off = (uintptr_t) (void *) value;
1069 u_long diff = off;
1070 u_long st_value;
1071 const Elf_Sym* es;
1072 const Elf_Sym* best = 0;
1073 int i;
1074
1075 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1076 if (es->st_name == 0)
1077 continue;
1078 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1079 if (off >= st_value) {
1080 if (off - st_value < diff) {
1081 diff = off - st_value;
1082 best = es;
1083 if (diff == 0)
1084 break;
1085 } else if (off - st_value == diff) {
1086 best = es;
1087 }
1088 }
1089 }
1090 if (best == 0)
1091 *diffp = off;
1092 else
1093 *diffp = diff;
1094 *sym = (c_linker_sym_t) best;
1095
1096 return 0;
1097}
1098
1099/*
1100 * Look up a linker set on an ELF system.
1101 */
1102static int
1103link_elf_lookup_set(linker_file_t lf, const char *name,
1104 void ***startp, void ***stopp, int *countp)
1105{
1106 c_linker_sym_t sym;
1107 linker_symval_t symval;
1108 char *setsym;
1109 void **start, **stop;
1110 int len, error = 0, count;
1111
1112 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1113 setsym = malloc(len, M_LINKER, M_WAITOK);
1114 if (setsym == NULL)
1115 return ENOMEM;
1116
1117 /* get address of first entry */
1118 snprintf(setsym, len, "%s%s", "__start_set_", name);
1119 error = link_elf_lookup_symbol(lf, setsym, &sym);
1120 if (error)
1121 goto out;
1122 link_elf_symbol_values(lf, sym, &symval);
1123 if (symval.value == 0) {
1124 error = ESRCH;
1125 goto out;
1126 }
1127 start = (void **)symval.value;
1128
1129 /* get address of last entry */
1130 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1131 error = link_elf_lookup_symbol(lf, setsym, &sym);
1132 if (error)
1133 goto out;
1134 link_elf_symbol_values(lf, sym, &symval);
1135 if (symval.value == 0) {
1136 error = ESRCH;
1137 goto out;
1138 }
1139 stop = (void **)symval.value;
1140
1141 /* and the number of entries */
1142 count = stop - start;
1143
1144 /* and copy out */
1145 if (startp)
1146 *startp = start;
1147 if (stopp)
1148 *stopp = stop;
1149 if (countp)
1150 *countp = count;
1151
1152out:
1153 free(setsym, M_LINKER);
1154 return error;
1155}
1156
1157static int
1158link_elf_each_function_name(linker_file_t file,
1159 int (*callback)(const char *, void *), void *opaque) {
1160 elf_file_t ef = (elf_file_t)file;
1161 const Elf_Sym* symp;
1162 int i, error;
1163
1164 /* Exhaustive search */
1165 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1166 if (symp->st_value != 0 &&
1167 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1168 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1169 if (error)
1170 return (error);
1171 }
1172 }
1173 return (0);
1174}