2 * Copyright (c) 1998 Doug Rabson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
26 * $FreeBSD: src/sys/kern/link_elf.c,v 1.24 1999/12/24 15:33:36 bde Exp $
29 #include <sys/param.h>
30 #include <sys/kernel.h>
31 #include <sys/systm.h>
32 #include <sys/malloc.h>
34 #include <sys/nlookup.h>
35 #include <sys/fcntl.h>
36 #include <sys/vnode.h>
37 #include <sys/linker.h>
38 #include <machine/elf.h>
41 #include <vm/vm_param.h>
42 #include <vm/vm_zone.h>
45 #include <vm/vm_object.h>
46 #include <vm/vm_kern.h>
47 #include <vm/vm_extern.h>
50 #include <vm/vm_map.h>
52 #if defined(__x86_64__) && defined(_KERNEL_VIRTUAL)
56 static int link_elf_preload_file(const char *, linker_file_t
*);
57 static int link_elf_preload_finish(linker_file_t
);
58 static int link_elf_load_file(const char*, linker_file_t
*);
59 static int link_elf_lookup_symbol(linker_file_t
, const char*,
61 static int link_elf_symbol_values(linker_file_t
, c_linker_sym_t
, linker_symval_t
*);
62 static int link_elf_search_symbol(linker_file_t
, caddr_t value
,
63 c_linker_sym_t
* sym
, long* diffp
);
65 static void link_elf_unload_file(linker_file_t
);
66 static void link_elf_unload_module(linker_file_t
);
67 static int link_elf_lookup_set(linker_file_t
, const char *,
68 void ***, void ***, int *);
69 static int elf_lookup(linker_file_t lf
, Elf_Size symidx
, int deps
, Elf_Addr
*);
70 static void link_elf_reloc_local(linker_file_t lf
);
72 static struct linker_class_ops link_elf_class_ops
= {
74 link_elf_preload_file
,
77 static struct linker_file_ops link_elf_file_ops
= {
78 .lookup_symbol
= link_elf_lookup_symbol
,
79 .symbol_values
= link_elf_symbol_values
,
80 .search_symbol
= link_elf_search_symbol
,
81 .unload
= link_elf_unload_file
,
82 .lookup_set
= link_elf_lookup_set
85 static struct linker_file_ops link_elf_module_ops
= {
86 .lookup_symbol
= link_elf_lookup_symbol
,
87 .symbol_values
= link_elf_symbol_values
,
88 .search_symbol
= link_elf_search_symbol
,
89 .preload_finish
= link_elf_preload_finish
,
90 .unload
= link_elf_unload_module
,
91 .lookup_set
= link_elf_lookup_set
,
94 typedef struct elf_file
{
95 caddr_t address
; /* Relocation address */
97 vm_object_t object
; /* VM object to hold file pages */
99 const Elf_Dyn
* dynamic
; /* Symbol table etc. */
100 Elf_Hashelt nbuckets
; /* DT_HASH info */
102 const Elf_Hashelt
* buckets
;
103 const Elf_Hashelt
* chains
;
105 caddr_t strtab
; /* DT_STRTAB */
106 int strsz
; /* DT_STRSZ */
107 const Elf_Sym
* symtab
; /* DT_SYMTAB */
108 Elf_Addr
* got
; /* DT_PLTGOT */
109 const Elf_Rel
* pltrel
; /* DT_JMPREL */
110 int pltrelsize
; /* DT_PLTRELSZ */
111 const Elf_Rela
* pltrela
; /* DT_JMPREL */
112 int pltrelasize
; /* DT_PLTRELSZ */
113 const Elf_Rel
* rel
; /* DT_REL */
114 int relsize
; /* DT_RELSZ */
115 const Elf_Rela
* rela
; /* DT_RELA */
116 int relasize
; /* DT_RELASZ */
118 const Elf_Sym
* ddbsymtab
; /* The symbol table we are using */
119 long ddbsymcnt
; /* Number of symbols */
120 caddr_t ddbstrtab
; /* String table */
121 long ddbstrcnt
; /* number of bytes in string table */
122 caddr_t symbase
; /* malloc'ed symbold base */
123 caddr_t strbase
; /* malloc'ed string base */
126 static int parse_dynamic(linker_file_t lf
);
127 static int relocate_file(linker_file_t lf
);
128 static int parse_module_symbols(linker_file_t lf
);
131 * The kernel symbol table starts here.
133 extern struct _dynamic _DYNAMIC
;
136 link_elf_init(void* arg
)
139 caddr_t modptr
, baseptr
, sizeptr
;
143 #if ELF_TARG_CLASS == ELFCLASS32
144 linker_add_class("elf32", NULL
, &link_elf_class_ops
);
146 linker_add_class("elf64", NULL
, &link_elf_class_ops
);
149 dp
= (Elf_Dyn
*) &_DYNAMIC
;
151 ef
= kmalloc(sizeof(struct elf_file
), M_LINKER
, M_INTWAIT
| M_ZERO
);
153 #ifdef SPARSE_MAPPING
158 modptr
= preload_search_by_type("elf kernel");
160 modname
= (char *)preload_search_info(modptr
, MODINFO_NAME
);
163 linker_kernel_file
= linker_make_file(modname
, ef
, &link_elf_file_ops
);
164 if (linker_kernel_file
== NULL
)
165 panic("link_elf_init: Can't create linker structures for kernel");
166 parse_dynamic(linker_kernel_file
);
167 #if defined(__x86_64__) && defined(_KERNEL_VIRTUAL)
168 fprintf(stderr
, "WARNING: KERNBASE being used\n");
170 linker_kernel_file
->address
= (caddr_t
) KERNBASE
;
171 linker_kernel_file
->size
= -(intptr_t)linker_kernel_file
->address
;
175 baseptr
= preload_search_info(modptr
, MODINFO_ADDR
);
177 linker_kernel_file
->address
= *(caddr_t
*)baseptr
;
178 sizeptr
= preload_search_info(modptr
, MODINFO_SIZE
);
180 linker_kernel_file
->size
= *(size_t *)sizeptr
;
182 parse_module_symbols(linker_kernel_file
);
183 linker_current_file
= linker_kernel_file
;
184 linker_kernel_file
->flags
|= LINKER_FILE_LINKED
;
188 SYSINIT(link_elf
, SI_BOOT2_KLD
, SI_ORDER_SECOND
, link_elf_init
, 0);
191 parse_module_symbols(linker_file_t lf
)
193 elf_file_t ef
= lf
->priv
;
195 caddr_t ssym
, esym
, base
;
201 if (ef
->modptr
== NULL
)
203 pointer
= preload_search_info(ef
->modptr
, MODINFO_METADATA
|MODINFOMD_SSYM
);
206 ssym
= *(caddr_t
*)pointer
;
207 pointer
= preload_search_info(ef
->modptr
, MODINFO_METADATA
|MODINFOMD_ESYM
);
210 esym
= *(caddr_t
*)pointer
;
214 symcnt
= *(long *)base
;
215 base
+= sizeof(long);
216 symtab
= (Elf_Sym
*)base
;
217 base
+= roundup(symcnt
, sizeof(long));
219 if (base
> esym
|| base
< ssym
) {
220 kprintf("Symbols are corrupt!\n");
224 strcnt
= *(long *)base
;
225 base
+= sizeof(long);
227 base
+= roundup(strcnt
, sizeof(long));
229 if (base
> esym
|| base
< ssym
) {
230 kprintf("Symbols are corrupt!\n");
234 ef
->ddbsymtab
= symtab
;
235 ef
->ddbsymcnt
= symcnt
/ sizeof(Elf_Sym
);
236 ef
->ddbstrtab
= strtab
;
237 ef
->ddbstrcnt
= strcnt
;
243 parse_dynamic(linker_file_t lf
)
245 elf_file_t ef
= lf
->priv
;
247 int plttype
= DT_REL
;
249 for (dp
= ef
->dynamic
; dp
->d_tag
!= DT_NULL
; dp
++) {
253 /* From src/libexec/rtld-elf/rtld.c */
254 const Elf_Hashelt
*hashtab
= (const Elf_Hashelt
*)
255 (ef
->address
+ dp
->d_un
.d_ptr
);
256 ef
->nbuckets
= hashtab
[0];
257 ef
->nchains
= hashtab
[1];
258 ef
->buckets
= hashtab
+ 2;
259 ef
->chains
= ef
->buckets
+ ef
->nbuckets
;
263 ef
->strtab
= (caddr_t
) (ef
->address
+ dp
->d_un
.d_ptr
);
266 ef
->strsz
= dp
->d_un
.d_val
;
269 ef
->symtab
= (Elf_Sym
*) (ef
->address
+ dp
->d_un
.d_ptr
);
272 if (dp
->d_un
.d_val
!= sizeof(Elf_Sym
))
276 ef
->got
= (Elf_Addr
*) (ef
->address
+ dp
->d_un
.d_ptr
);
279 ef
->rel
= (const Elf_Rel
*) (ef
->address
+ dp
->d_un
.d_ptr
);
282 ef
->relsize
= dp
->d_un
.d_val
;
285 if (dp
->d_un
.d_val
!= sizeof(Elf_Rel
))
289 ef
->pltrel
= (const Elf_Rel
*) (ef
->address
+ dp
->d_un
.d_ptr
);
292 ef
->pltrelsize
= dp
->d_un
.d_val
;
295 ef
->rela
= (const Elf_Rela
*) (ef
->address
+ dp
->d_un
.d_ptr
);
298 ef
->relasize
= dp
->d_un
.d_val
;
301 if (dp
->d_un
.d_val
!= sizeof(Elf_Rela
))
305 plttype
= dp
->d_un
.d_val
;
306 if (plttype
!= DT_REL
&& plttype
!= DT_RELA
)
312 if (plttype
== DT_RELA
) {
313 ef
->pltrela
= (const Elf_Rela
*) ef
->pltrel
;
315 ef
->pltrelasize
= ef
->pltrelsize
;
319 ef
->ddbsymtab
= ef
->symtab
;
320 ef
->ddbsymcnt
= ef
->nchains
;
321 ef
->ddbstrtab
= ef
->strtab
;
322 ef
->ddbstrcnt
= ef
->strsz
;
328 link_elf_error(const char *s
)
330 kprintf("kldload: %s\n", s
);
334 link_elf_preload_file(const char *filename
, linker_file_t
*result
)
336 caddr_t modptr
, baseptr
, sizeptr
, dynptr
;
344 * Look to see if we have the module preloaded.
346 modptr
= preload_search_by_name(filename
);
350 /* It's preloaded, check we can handle it and collect information */
351 type
= (char *)preload_search_info(modptr
, MODINFO_TYPE
);
352 baseptr
= preload_search_info(modptr
, MODINFO_ADDR
);
353 sizeptr
= preload_search_info(modptr
, MODINFO_SIZE
);
354 dynptr
= preload_search_info(modptr
, MODINFO_METADATA
|MODINFOMD_DYNAMIC
);
356 (strcmp(type
, "elf" __XSTRING(__ELF_WORD_SIZE
) " module") != 0 &&
357 strcmp(type
, "elf module") != 0))
359 if (baseptr
== NULL
|| sizeptr
== NULL
|| dynptr
== NULL
)
362 ef
= kmalloc(sizeof(struct elf_file
), M_LINKER
, M_WAITOK
| M_ZERO
);
364 ef
->address
= *(caddr_t
*)baseptr
;
365 #ifdef SPARSE_MAPPING
368 dp
= (vm_offset_t
)ef
->address
+ *(vm_offset_t
*)dynptr
;
369 ef
->dynamic
= (Elf_Dyn
*)dp
;
370 lf
= linker_make_file(filename
, ef
, &link_elf_module_ops
);
375 lf
->address
= ef
->address
;
376 lf
->size
= *(size_t *)sizeptr
;
378 error
= parse_dynamic(lf
);
380 linker_file_unload(lf
);
383 link_elf_reloc_local(lf
);
389 link_elf_preload_finish(linker_file_t lf
)
393 error
= relocate_file(lf
);
396 parse_module_symbols(lf
);
402 link_elf_load_file(const char* filename
, linker_file_t
* result
)
404 struct nlookupdata nd
;
405 struct thread
*td
= curthread
; /* XXX */
406 struct proc
*p
= td
->td_proc
;
419 Elf_Addr base_vlimit
;
431 /* XXX Hack for firmware loading where p == NULL */
437 if (p
->p_ucred
== NULL
) {
438 kprintf("link_elf_load_file: cannot load '%s' from filesystem"
439 " this early\n", filename
);
444 pathname
= linker_search_path(filename
);
445 if (pathname
== NULL
)
448 error
= nlookup_init(&nd
, pathname
, UIO_SYSSPACE
, NLC_FOLLOW
|NLC_LOCKVP
);
450 error
= vn_open(&nd
, NULL
, FREAD
, 0);
451 kfree(pathname
, M_LINKER
);
457 nd
.nl_open_vp
= NULL
;
461 * Read the elf header from the file.
463 firstpage
= kmalloc(PAGE_SIZE
, M_LINKER
, M_WAITOK
);
464 hdr
= (Elf_Ehdr
*)firstpage
;
465 error
= vn_rdwr(UIO_READ
, vp
, firstpage
, PAGE_SIZE
, 0,
466 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
467 nbytes
= PAGE_SIZE
- resid
;
476 if (hdr
->e_ident
[EI_CLASS
] != ELF_TARG_CLASS
477 || hdr
->e_ident
[EI_DATA
] != ELF_TARG_DATA
) {
478 link_elf_error("Unsupported file layout");
482 if (hdr
->e_ident
[EI_VERSION
] != EV_CURRENT
483 || hdr
->e_version
!= EV_CURRENT
) {
484 link_elf_error("Unsupported file version");
488 if (hdr
->e_type
!= ET_EXEC
&& hdr
->e_type
!= ET_DYN
) {
492 if (hdr
->e_machine
!= ELF_TARG_MACH
) {
493 link_elf_error("Unsupported machine");
499 * We rely on the program header being in the first page. This is
500 * not strictly required by the ABI specification, but it seems to
501 * always true in practice. And, it simplifies things considerably.
503 if (!((hdr
->e_phentsize
== sizeof(Elf_Phdr
)) &&
504 (hdr
->e_phoff
+ hdr
->e_phnum
*sizeof(Elf_Phdr
) <= PAGE_SIZE
) &&
505 (hdr
->e_phoff
+ hdr
->e_phnum
*sizeof(Elf_Phdr
) <= nbytes
)))
506 link_elf_error("Unreadable program headers");
509 * Scan the program header entries, and save key information.
511 * We rely on there being exactly two load segments, text and data,
514 phdr
= (Elf_Phdr
*) (firstpage
+ hdr
->e_phoff
);
515 phlimit
= phdr
+ hdr
->e_phnum
;
518 while (phdr
< phlimit
) {
519 switch (phdr
->p_type
) {
523 link_elf_error("Too many sections");
546 link_elf_error("Object is not dynamically-linked");
552 * Allocate the entire address space of the object, to stake out our
553 * contiguous region, and to establish the base address for relocation.
555 base_vaddr
= trunc_page(segs
[0]->p_vaddr
);
556 base_vlimit
= round_page(segs
[1]->p_vaddr
+ segs
[1]->p_memsz
);
557 mapsize
= base_vlimit
- base_vaddr
;
559 ef
= kmalloc(sizeof(struct elf_file
), M_LINKER
, M_WAITOK
| M_ZERO
);
560 #ifdef SPARSE_MAPPING
561 ef
->object
= vm_object_allocate(OBJT_DEFAULT
, mapsize
>> PAGE_SHIFT
);
562 if (ef
->object
== NULL
) {
567 vm_object_hold(ef
->object
);
568 vm_object_reference_locked(ef
->object
);
569 ef
->address
= (caddr_t
)vm_map_min(&kernel_map
);
570 error
= vm_map_find(&kernel_map
, ef
->object
, 0,
571 (vm_offset_t
*)&ef
->address
,
573 1, VM_MAPTYPE_NORMAL
,
574 VM_PROT_ALL
, VM_PROT_ALL
,
576 vm_object_drop(ef
->object
);
578 vm_object_deallocate(ef
->object
);
583 ef
->address
= kmalloc(mapsize
, M_LINKER
, M_WAITOK
);
585 mapbase
= ef
->address
;
588 * Read the text and data sections and zero the bss.
590 for (i
= 0; i
< 2; i
++) {
591 caddr_t segbase
= mapbase
+ segs
[i
]->p_vaddr
- base_vaddr
;
592 error
= vn_rdwr(UIO_READ
, vp
,
593 segbase
, segs
[i
]->p_filesz
, segs
[i
]->p_offset
,
594 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
596 #ifdef SPARSE_MAPPING
597 vm_map_remove(&kernel_map
, (vm_offset_t
) ef
->address
,
598 (vm_offset_t
) ef
->address
599 + (ef
->object
->size
<< PAGE_SHIFT
));
600 vm_object_deallocate(ef
->object
);
602 kfree(ef
->address
, M_LINKER
);
607 bzero(segbase
+ segs
[i
]->p_filesz
,
608 segs
[i
]->p_memsz
- segs
[i
]->p_filesz
);
610 #ifdef SPARSE_MAPPING
612 * Wire down the pages
614 vm_map_wire(&kernel_map
,
615 (vm_offset_t
) segbase
,
616 (vm_offset_t
) segbase
+ segs
[i
]->p_memsz
,
621 ef
->dynamic
= (const Elf_Dyn
*) (mapbase
+ phdyn
->p_vaddr
- base_vaddr
);
623 lf
= linker_make_file(filename
, ef
, &link_elf_file_ops
);
625 #ifdef SPARSE_MAPPING
626 vm_map_remove(&kernel_map
, (vm_offset_t
) ef
->address
,
627 (vm_offset_t
) ef
->address
628 + (ef
->object
->size
<< PAGE_SHIFT
));
629 vm_object_deallocate(ef
->object
);
631 kfree(ef
->address
, M_LINKER
);
637 lf
->address
= ef
->address
;
640 error
= parse_dynamic(lf
);
643 link_elf_reloc_local(lf
);
644 error
= linker_load_dependencies(lf
);
647 error
= relocate_file(lf
);
651 /* Try and load the symbol table if it's present. (you can strip it!) */
652 nbytes
= hdr
->e_shnum
* hdr
->e_shentsize
;
653 if (nbytes
== 0 || hdr
->e_shoff
== 0)
655 shdr
= kmalloc(nbytes
, M_LINKER
, M_WAITOK
| M_ZERO
);
656 error
= vn_rdwr(UIO_READ
, vp
,
657 (caddr_t
)shdr
, nbytes
, hdr
->e_shoff
,
658 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
663 for (i
= 0; i
< hdr
->e_shnum
; i
++) {
664 if (shdr
[i
].sh_type
== SHT_SYMTAB
) {
666 symstrindex
= shdr
[i
].sh_link
;
669 if (symtabindex
< 0 || symstrindex
< 0)
672 symcnt
= shdr
[symtabindex
].sh_size
;
673 ef
->symbase
= kmalloc(symcnt
, M_LINKER
, M_WAITOK
);
674 strcnt
= shdr
[symstrindex
].sh_size
;
675 ef
->strbase
= kmalloc(strcnt
, M_LINKER
, M_WAITOK
);
676 error
= vn_rdwr(UIO_READ
, vp
,
677 ef
->symbase
, symcnt
, shdr
[symtabindex
].sh_offset
,
678 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
681 error
= vn_rdwr(UIO_READ
, vp
,
682 ef
->strbase
, strcnt
, shdr
[symstrindex
].sh_offset
,
683 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
687 ef
->ddbsymcnt
= symcnt
/ sizeof(Elf_Sym
);
688 ef
->ddbsymtab
= (const Elf_Sym
*)ef
->symbase
;
689 ef
->ddbstrcnt
= strcnt
;
690 ef
->ddbstrtab
= ef
->strbase
;
698 linker_file_unload(lf
);
700 kfree(shdr
, M_LINKER
);
702 kfree(firstpage
, M_LINKER
);
710 elf_relocaddr(linker_file_t lf
, Elf_Addr x
)
716 if (x
>= ef
->pcpu_start
&& x
< ef
->pcpu_stop
)
717 return ((x
- ef
->pcpu_start
) + ef
->pcpu_base
);
719 if (x
>= ef
->vnet_start
&& x
< ef
->vnet_stop
)
720 return ((x
- ef
->vnet_start
) + ef
->vnet_base
);
727 link_elf_unload_file(linker_file_t file
)
729 elf_file_t ef
= file
->priv
;
732 #ifdef SPARSE_MAPPING
734 vm_map_remove(&kernel_map
, (vm_offset_t
) ef
->address
,
735 (vm_offset_t
) ef
->address
736 + (ef
->object
->size
<< PAGE_SHIFT
));
737 vm_object_deallocate(ef
->object
);
741 kfree(ef
->address
, M_LINKER
);
744 kfree(ef
->symbase
, M_LINKER
);
746 kfree(ef
->strbase
, M_LINKER
);
752 link_elf_unload_module(linker_file_t file
)
754 elf_file_t ef
= file
->priv
;
759 preload_delete_name(file
->filename
);
763 symbol_name(elf_file_t ef
, Elf_Size r_info
)
767 if (ELF_R_SYM(r_info
)) {
768 ref
= ef
->symtab
+ ELF_R_SYM(r_info
);
769 return ef
->strtab
+ ref
->st_name
;
775 relocate_file(linker_file_t lf
)
777 elf_file_t ef
= lf
->priv
;
778 const Elf_Rel
*rellim
;
780 const Elf_Rela
*relalim
;
781 const Elf_Rela
*rela
;
784 /* Perform relocations without addend if there are any: */
787 rellim
= (const Elf_Rel
*)((const char *)ef
->rel
+ ef
->relsize
);
788 while (rel
< rellim
) {
789 if (elf_reloc(lf
, (Elf_Addr
)ef
->address
, rel
, ELF_RELOC_REL
, elf_lookup
)) {
790 symname
= symbol_name(ef
, rel
->r_info
);
791 kprintf("link_elf: symbol %s undefined\n", symname
);
798 /* Perform relocations with addend if there are any: */
801 relalim
= (const Elf_Rela
*)((const char *)ef
->rela
+ ef
->relasize
);
802 while (rela
< relalim
) {
803 if (elf_reloc(lf
, (Elf_Addr
)ef
->address
, rela
, ELF_RELOC_RELA
, elf_lookup
)) {
804 symname
= symbol_name(ef
, rela
->r_info
);
805 kprintf("link_elf: symbol %s undefined\n", symname
);
812 /* Perform PLT relocations without addend if there are any: */
815 rellim
= (const Elf_Rel
*)((const char *)ef
->pltrel
+ ef
->pltrelsize
);
816 while (rel
< rellim
) {
817 if (elf_reloc(lf
, (Elf_Addr
)ef
->address
, rel
, ELF_RELOC_REL
, elf_lookup
)) {
818 symname
= symbol_name(ef
, rel
->r_info
);
819 kprintf("link_elf: symbol %s undefined\n", symname
);
826 /* Perform relocations with addend if there are any: */
829 relalim
= (const Elf_Rela
*)((const char *)ef
->pltrela
+ ef
->pltrelasize
);
830 while (rela
< relalim
) {
831 symname
= symbol_name(ef
, rela
->r_info
);
832 if (elf_reloc(lf
, (Elf_Addr
)ef
->address
, rela
, ELF_RELOC_RELA
, elf_lookup
)) {
833 kprintf("link_elf: symbol %s undefined\n", symname
);
844 * Hash function for symbol table lookup. Don't even think about changing
845 * this. It is specified by the System V ABI.
848 elf_hash(const char *name
)
850 const unsigned char *p
= (const unsigned char *) name
;
856 if ((g
= h
& 0xf0000000) != 0)
864 link_elf_lookup_symbol(linker_file_t lf
, const char* name
, c_linker_sym_t
* sym
)
866 elf_file_t ef
= lf
->priv
;
867 unsigned long symnum
;
873 /* If we don't have a hash, bail. */
874 if (ef
->buckets
== NULL
|| ef
->nbuckets
== 0) {
875 kprintf("link_elf_lookup_symbol: missing symbol hash table\n");
879 /* First, search hashed global symbols */
880 hash
= elf_hash(name
);
881 symnum
= ef
->buckets
[hash
% ef
->nbuckets
];
883 while (symnum
!= STN_UNDEF
) {
884 if (symnum
>= ef
->nchains
) {
885 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
889 symp
= ef
->symtab
+ symnum
;
890 if (symp
->st_name
== 0) {
891 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
895 strp
= ef
->strtab
+ symp
->st_name
;
897 if (strcmp(name
, strp
) == 0) {
898 if (symp
->st_shndx
!= SHN_UNDEF
||
899 (symp
->st_value
!= 0 &&
900 ELF_ST_TYPE(symp
->st_info
) == STT_FUNC
)
902 *sym
= (c_linker_sym_t
) symp
;
909 symnum
= ef
->chains
[symnum
];
912 /* If we have not found it, look at the full table (if loaded) */
913 if (ef
->symtab
== ef
->ddbsymtab
)
916 /* Exhaustive search */
917 for (i
= 0, symp
= ef
->ddbsymtab
; i
< ef
->ddbsymcnt
; i
++, symp
++) {
918 strp
= ef
->ddbstrtab
+ symp
->st_name
;
919 if (strcmp(name
, strp
) == 0) {
920 if (symp
->st_shndx
!= SHN_UNDEF
||
921 (symp
->st_value
!= 0 &&
922 ELF_ST_TYPE(symp
->st_info
) == STT_FUNC
)) {
923 *sym
= (c_linker_sym_t
) symp
;
934 link_elf_symbol_values(linker_file_t lf
, c_linker_sym_t sym
, linker_symval_t
*symval
)
936 elf_file_t ef
= lf
->priv
;
937 const Elf_Sym
*es
= (const Elf_Sym
*)sym
;
939 if (es
>= ef
->symtab
&& ((es
- ef
->symtab
) < ef
->nchains
)) {
940 symval
->name
= ef
->strtab
+ es
->st_name
;
941 symval
->value
= ef
->address
+ es
->st_value
;
942 symval
->size
= es
->st_size
;
945 if (ef
->symtab
== ef
->ddbsymtab
)
947 if (es
>= ef
->ddbsymtab
&& ((es
- ef
->ddbsymtab
) < ef
->ddbsymcnt
)) {
948 symval
->name
= ef
->ddbstrtab
+ es
->st_name
;
949 symval
->value
= ef
->address
+ es
->st_value
;
950 symval
->size
= es
->st_size
;
957 link_elf_search_symbol(linker_file_t lf
, caddr_t value
,
958 c_linker_sym_t
*sym
, long *diffp
)
960 elf_file_t ef
= lf
->priv
;
961 u_long off
= (uintptr_t)(void *)value
;
965 const Elf_Sym
*best
= NULL
;
968 for (i
= 0, es
= ef
->ddbsymtab
; i
< ef
->ddbsymcnt
; i
++, es
++) {
969 if (es
->st_name
== 0)
971 st_value
= es
->st_value
+ (uintptr_t)(void *)ef
->address
;
972 if (off
>= st_value
) {
973 if (off
- st_value
< diff
) {
974 diff
= off
- st_value
;
978 } else if (off
- st_value
== diff
) {
987 *sym
= (c_linker_sym_t
) best
;
993 * Look up a linker set on an ELF system.
996 link_elf_lookup_set(linker_file_t lf
, const char *name
,
997 void ***startp
, void ***stopp
, int *countp
)
1000 linker_symval_t symval
;
1002 void **start
, **stop
;
1003 int len
, error
= 0, count
;
1005 len
= strlen(name
) + sizeof("__start_set_"); /* sizeof includes \0 */
1006 setsym
= kmalloc(len
, M_LINKER
, M_WAITOK
);
1008 /* get address of first entry */
1009 ksnprintf(setsym
, len
, "%s%s", "__start_set_", name
);
1010 error
= link_elf_lookup_symbol(lf
, setsym
, &sym
);
1013 link_elf_symbol_values(lf
, sym
, &symval
);
1014 if (symval
.value
== NULL
) {
1018 start
= (void **)symval
.value
;
1020 /* get address of last entry */
1021 ksnprintf(setsym
, len
, "%s%s", "__stop_set_", name
);
1022 error
= link_elf_lookup_symbol(lf
, setsym
, &sym
);
1025 link_elf_symbol_values(lf
, sym
, &symval
);
1026 if (symval
.value
== NULL
) {
1030 stop
= (void **)symval
.value
;
1032 /* and the number of entries */
1033 count
= stop
- start
;
1044 kfree(setsym
, M_LINKER
);
1049 * Symbol lookup function that can be used when the symbol index is known (ie
1050 * in relocations). It uses the symbol index instead of doing a fully fledged
1051 * hash table based lookup when such is valid. For example for local symbols.
1052 * This is not only more efficient, it's also more correct. It's not always
1053 * the case that the symbol can be found through the hash table.
1056 elf_lookup(linker_file_t lf
, Elf_Size symidx
, int deps
, Elf_Addr
*result
)
1058 elf_file_t ef
= lf
->priv
;
1062 /* Don't even try to lookup the symbol if the index is bogus. */
1063 if (symidx
>= ef
->nchains
)
1066 sym
= ef
->symtab
+ symidx
;
1069 * Don't do a full lookup when the symbol is local. It may even
1070 * fail because it may not be found through the hash table.
1072 if (ELF_ST_BIND(sym
->st_info
) == STB_LOCAL
) {
1073 /* Force lookup failure when we have an insanity. */
1074 if (sym
->st_shndx
== SHN_UNDEF
|| sym
->st_value
== 0)
1076 return ((Elf_Addr
) ef
->address
+ sym
->st_value
);
1079 * XXX we can avoid doing a hash table based lookup for global
1080 * symbols as well. This however is not always valid, so we'll
1081 * just do it the hard way for now. Performance tweaks can
1085 symbol
= ef
->strtab
+ sym
->st_name
;
1087 /* Force a lookup failure if the symbol name is bogus. */
1091 return (linker_file_lookup_symbol(lf
, symbol
, deps
, (caddr_t
*)result
));
1094 link_elf_reloc_local(linker_file_t lf
)
1096 elf_file_t ef
= lf
->priv
;
1097 const Elf_Rel
*rellim
;
1099 const Elf_Rela
*relalim
;
1100 const Elf_Rela
*rela
;
1102 /* Perform relocations without addend if there are any: */
1103 if ((rel
= ef
->rel
) != NULL
) {
1104 rellim
= (const Elf_Rel
*)((const char *)ef
->rel
+ ef
->relsize
);
1105 while (rel
< rellim
) {
1106 elf_reloc_local(lf
, (Elf_Addr
)ef
->address
, rel
, ELF_RELOC_REL
,
1112 /* Perform relocations with addend if there are any: */
1113 if ((rela
= ef
->rela
) != NULL
) {
1114 relalim
= (const Elf_Rela
*)((const char *)ef
->rela
+ ef
->relasize
);
1115 while (rela
< relalim
) {
1116 elf_reloc_local(lf
, (Elf_Addr
)ef
->address
, rela
, ELF_RELOC_RELA
,