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