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 $
27 * $DragonFly: src/sys/kern/link_elf.c,v 1.29 2008/08/01 23:11:16 dillon Exp $
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/systm.h>
33 #include <sys/malloc.h>
35 #include <sys/nlookup.h>
36 #include <sys/fcntl.h>
37 #include <sys/vnode.h>
38 #include <sys/linker.h>
39 #include <machine/elf.h>
42 #include <vm/vm_param.h>
43 #include <vm/vm_zone.h>
46 #include <vm/vm_object.h>
47 #include <vm/vm_kern.h>
48 #include <vm/vm_extern.h>
51 #include <vm/vm_map.h>
53 static int link_elf_preload_file(const char *, linker_file_t
*);
54 static int link_elf_preload_finish(linker_file_t
);
55 static int link_elf_load_file(const char*, linker_file_t
*);
56 static int link_elf_lookup_symbol(linker_file_t
, const char*,
58 static int link_elf_symbol_values(linker_file_t
, c_linker_sym_t
, linker_symval_t
*);
59 static int link_elf_search_symbol(linker_file_t
, caddr_t value
,
60 c_linker_sym_t
* sym
, long* diffp
);
62 static void link_elf_unload_file(linker_file_t
);
63 static void link_elf_unload_module(linker_file_t
);
64 static int link_elf_lookup_set(linker_file_t
, const char *,
65 void ***, void ***, int *);
66 static int elf_lookup(linker_file_t lf
, Elf_Size symidx
, int deps
, Elf_Addr
*);
67 static void link_elf_reloc_local(linker_file_t lf
);
69 static struct linker_class_ops link_elf_class_ops
= {
71 link_elf_preload_file
,
74 static struct linker_file_ops link_elf_file_ops
= {
75 .lookup_symbol
= link_elf_lookup_symbol
,
76 .symbol_values
= link_elf_symbol_values
,
77 .search_symbol
= link_elf_search_symbol
,
78 .unload
= link_elf_unload_file
,
79 .lookup_set
= link_elf_lookup_set
82 static struct linker_file_ops link_elf_module_ops
= {
83 .lookup_symbol
= link_elf_lookup_symbol
,
84 .symbol_values
= link_elf_symbol_values
,
85 .search_symbol
= link_elf_search_symbol
,
86 .preload_finish
= link_elf_preload_finish
,
87 .unload
= link_elf_unload_module
,
88 .lookup_set
= link_elf_lookup_set
,
91 typedef struct elf_file
{
92 caddr_t address
; /* Relocation address */
94 vm_object_t object
; /* VM object to hold file pages */
96 const Elf_Dyn
* dynamic
; /* Symbol table etc. */
97 Elf_Hashelt nbuckets
; /* DT_HASH info */
99 const Elf_Hashelt
* buckets
;
100 const Elf_Hashelt
* chains
;
102 caddr_t strtab
; /* DT_STRTAB */
103 int strsz
; /* DT_STRSZ */
104 const Elf_Sym
* symtab
; /* DT_SYMTAB */
105 Elf_Addr
* got
; /* DT_PLTGOT */
106 const Elf_Rel
* pltrel
; /* DT_JMPREL */
107 int pltrelsize
; /* DT_PLTRELSZ */
108 const Elf_Rela
* pltrela
; /* DT_JMPREL */
109 int pltrelasize
; /* DT_PLTRELSZ */
110 const Elf_Rel
* rel
; /* DT_REL */
111 int relsize
; /* DT_RELSZ */
112 const Elf_Rela
* rela
; /* DT_RELA */
113 int relasize
; /* DT_RELASZ */
115 const Elf_Sym
* ddbsymtab
; /* The symbol table we are using */
116 long ddbsymcnt
; /* Number of symbols */
117 caddr_t ddbstrtab
; /* String table */
118 long ddbstrcnt
; /* number of bytes in string table */
119 caddr_t symbase
; /* malloc'ed symbold base */
120 caddr_t strbase
; /* malloc'ed string base */
123 static int parse_dynamic(linker_file_t lf
);
124 static int relocate_file(linker_file_t lf
);
125 static int parse_module_symbols(linker_file_t lf
);
128 * The kernel symbol table starts here.
130 extern struct _dynamic _DYNAMIC
;
133 link_elf_init(void* arg
)
136 caddr_t modptr
, baseptr
, sizeptr
;
140 #if ELF_TARG_CLASS == ELFCLASS32
141 linker_add_class("elf32", NULL
, &link_elf_class_ops
);
143 linker_add_class("elf64", NULL
, &link_elf_class_ops
);
146 dp
= (Elf_Dyn
*) &_DYNAMIC
;
148 ef
= kmalloc(sizeof(struct elf_file
), M_LINKER
, M_INTWAIT
| M_ZERO
);
150 #ifdef SPARSE_MAPPING
155 modptr
= preload_search_by_type("elf kernel");
157 modname
= (char *)preload_search_info(modptr
, MODINFO_NAME
);
160 linker_kernel_file
= linker_make_file(modname
, ef
, &link_elf_file_ops
);
161 if (linker_kernel_file
== NULL
)
162 panic("link_elf_init: Can't create linker structures for kernel");
163 parse_dynamic(linker_kernel_file
);
164 linker_kernel_file
->address
= (caddr_t
) KERNBASE
;
165 linker_kernel_file
->size
= -(intptr_t)linker_kernel_file
->address
;
169 baseptr
= preload_search_info(modptr
, MODINFO_ADDR
);
171 linker_kernel_file
->address
= *(caddr_t
*)baseptr
;
172 sizeptr
= preload_search_info(modptr
, MODINFO_SIZE
);
174 linker_kernel_file
->size
= *(size_t *)sizeptr
;
176 parse_module_symbols(linker_kernel_file
);
177 linker_current_file
= linker_kernel_file
;
178 linker_kernel_file
->flags
|= LINKER_FILE_LINKED
;
182 SYSINIT(link_elf
, SI_BOOT2_KLD
, SI_ORDER_SECOND
, link_elf_init
, 0);
185 parse_module_symbols(linker_file_t lf
)
187 elf_file_t ef
= lf
->priv
;
189 caddr_t ssym
, esym
, base
;
195 if (ef
->modptr
== NULL
)
197 pointer
= preload_search_info(ef
->modptr
, MODINFO_METADATA
|MODINFOMD_SSYM
);
200 ssym
= *(caddr_t
*)pointer
;
201 pointer
= preload_search_info(ef
->modptr
, MODINFO_METADATA
|MODINFOMD_ESYM
);
204 esym
= *(caddr_t
*)pointer
;
208 symcnt
= *(long *)base
;
209 base
+= sizeof(long);
210 symtab
= (Elf_Sym
*)base
;
211 base
+= roundup(symcnt
, sizeof(long));
213 if (base
> esym
|| base
< ssym
) {
214 kprintf("Symbols are corrupt!\n");
218 strcnt
= *(long *)base
;
219 base
+= sizeof(long);
221 base
+= roundup(strcnt
, sizeof(long));
223 if (base
> esym
|| base
< ssym
) {
224 kprintf("Symbols are corrupt!\n");
228 ef
->ddbsymtab
= symtab
;
229 ef
->ddbsymcnt
= symcnt
/ sizeof(Elf_Sym
);
230 ef
->ddbstrtab
= strtab
;
231 ef
->ddbstrcnt
= strcnt
;
237 parse_dynamic(linker_file_t lf
)
239 elf_file_t ef
= lf
->priv
;
241 int plttype
= DT_REL
;
243 for (dp
= ef
->dynamic
; dp
->d_tag
!= DT_NULL
; dp
++) {
247 /* From src/libexec/rtld-elf/rtld.c */
248 const Elf_Hashelt
*hashtab
= (const Elf_Hashelt
*)
249 (ef
->address
+ dp
->d_un
.d_ptr
);
250 ef
->nbuckets
= hashtab
[0];
251 ef
->nchains
= hashtab
[1];
252 ef
->buckets
= hashtab
+ 2;
253 ef
->chains
= ef
->buckets
+ ef
->nbuckets
;
257 ef
->strtab
= (caddr_t
) (ef
->address
+ dp
->d_un
.d_ptr
);
260 ef
->strsz
= dp
->d_un
.d_val
;
263 ef
->symtab
= (Elf_Sym
*) (ef
->address
+ dp
->d_un
.d_ptr
);
266 if (dp
->d_un
.d_val
!= sizeof(Elf_Sym
))
270 ef
->got
= (Elf_Addr
*) (ef
->address
+ dp
->d_un
.d_ptr
);
273 ef
->rel
= (const Elf_Rel
*) (ef
->address
+ dp
->d_un
.d_ptr
);
276 ef
->relsize
= dp
->d_un
.d_val
;
279 if (dp
->d_un
.d_val
!= sizeof(Elf_Rel
))
283 ef
->pltrel
= (const Elf_Rel
*) (ef
->address
+ dp
->d_un
.d_ptr
);
286 ef
->pltrelsize
= dp
->d_un
.d_val
;
289 ef
->rela
= (const Elf_Rela
*) (ef
->address
+ dp
->d_un
.d_ptr
);
292 ef
->relasize
= dp
->d_un
.d_val
;
295 if (dp
->d_un
.d_val
!= sizeof(Elf_Rela
))
299 plttype
= dp
->d_un
.d_val
;
300 if (plttype
!= DT_REL
&& plttype
!= DT_RELA
)
306 if (plttype
== DT_RELA
) {
307 ef
->pltrela
= (const Elf_Rela
*) ef
->pltrel
;
309 ef
->pltrelasize
= ef
->pltrelsize
;
313 ef
->ddbsymtab
= ef
->symtab
;
314 ef
->ddbsymcnt
= ef
->nchains
;
315 ef
->ddbstrtab
= ef
->strtab
;
316 ef
->ddbstrcnt
= ef
->strsz
;
322 link_elf_error(const char *s
)
324 kprintf("kldload: %s\n", s
);
328 link_elf_preload_file(const char *filename
, linker_file_t
*result
)
330 caddr_t modptr
, baseptr
, sizeptr
, dynptr
;
338 * Look to see if we have the module preloaded.
340 modptr
= preload_search_by_name(filename
);
344 /* It's preloaded, check we can handle it and collect information */
345 type
= (char *)preload_search_info(modptr
, MODINFO_TYPE
);
346 baseptr
= preload_search_info(modptr
, MODINFO_ADDR
);
347 sizeptr
= preload_search_info(modptr
, MODINFO_SIZE
);
348 dynptr
= preload_search_info(modptr
, MODINFO_METADATA
|MODINFOMD_DYNAMIC
);
350 (strcmp(type
, "elf" __XSTRING(__ELF_WORD_SIZE
) " module") != 0 &&
351 strcmp(type
, "elf module") != 0))
353 if (baseptr
== NULL
|| sizeptr
== NULL
|| dynptr
== NULL
)
356 ef
= kmalloc(sizeof(struct elf_file
), M_LINKER
, M_WAITOK
| M_ZERO
);
358 ef
->address
= *(caddr_t
*)baseptr
;
359 #ifdef SPARSE_MAPPING
362 dp
= (vm_offset_t
)ef
->address
+ *(vm_offset_t
*)dynptr
;
363 ef
->dynamic
= (Elf_Dyn
*)dp
;
364 lf
= linker_make_file(filename
, ef
, &link_elf_module_ops
);
369 lf
->address
= ef
->address
;
370 lf
->size
= *(size_t *)sizeptr
;
372 error
= parse_dynamic(lf
);
374 linker_file_unload(lf
);
377 link_elf_reloc_local(lf
);
383 link_elf_preload_finish(linker_file_t lf
)
387 error
= relocate_file(lf
);
390 parse_module_symbols(lf
);
396 link_elf_load_file(const char* filename
, linker_file_t
* result
)
398 struct nlookupdata nd
;
399 struct thread
*td
= curthread
; /* XXX */
400 struct proc
*p
= td
->td_proc
;
415 Elf_Addr base_vlimit
;
428 if (p
->p_ucred
== NULL
) {
429 kprintf("link_elf_load_file: cannot load '%s' from filesystem"
430 " this early\n", filename
);
435 pathname
= linker_search_path(filename
);
436 if (pathname
== NULL
)
439 error
= nlookup_init(&nd
, pathname
, UIO_SYSSPACE
, NLC_FOLLOW
|NLC_LOCKVP
);
441 error
= vn_open(&nd
, NULL
, FREAD
, 0);
442 kfree(pathname
, M_LINKER
);
448 nd
.nl_open_vp
= NULL
;
452 * Read the elf header from the file.
454 firstpage
= kmalloc(PAGE_SIZE
, M_LINKER
, M_WAITOK
);
455 hdr
= (Elf_Ehdr
*)firstpage
;
456 error
= vn_rdwr(UIO_READ
, vp
, firstpage
, PAGE_SIZE
, 0,
457 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
458 nbytes
= PAGE_SIZE
- resid
;
467 if (hdr
->e_ident
[EI_CLASS
] != ELF_TARG_CLASS
468 || hdr
->e_ident
[EI_DATA
] != ELF_TARG_DATA
) {
469 link_elf_error("Unsupported file layout");
473 if (hdr
->e_ident
[EI_VERSION
] != EV_CURRENT
474 || hdr
->e_version
!= EV_CURRENT
) {
475 link_elf_error("Unsupported file version");
479 if (hdr
->e_type
!= ET_EXEC
&& hdr
->e_type
!= ET_DYN
) {
483 if (hdr
->e_machine
!= ELF_TARG_MACH
) {
484 link_elf_error("Unsupported machine");
490 * We rely on the program header being in the first page. This is
491 * not strictly required by the ABI specification, but it seems to
492 * always true in practice. And, it simplifies things considerably.
494 if (!((hdr
->e_phentsize
== sizeof(Elf_Phdr
)) &&
495 (hdr
->e_phoff
+ hdr
->e_phnum
*sizeof(Elf_Phdr
) <= PAGE_SIZE
) &&
496 (hdr
->e_phoff
+ hdr
->e_phnum
*sizeof(Elf_Phdr
) <= nbytes
)))
497 link_elf_error("Unreadable program headers");
500 * Scan the program header entries, and save key information.
502 * We rely on there being exactly two load segments, text and data,
505 phdr
= (Elf_Phdr
*) (firstpage
+ hdr
->e_phoff
);
506 phlimit
= phdr
+ hdr
->e_phnum
;
510 while (phdr
< phlimit
) {
511 switch (phdr
->p_type
) {
515 link_elf_error("Too many sections");
539 link_elf_error("Object is not dynamically-linked");
545 * Allocate the entire address space of the object, to stake out our
546 * contiguous region, and to establish the base address for relocation.
548 base_offset
= trunc_page(segs
[0]->p_offset
);
549 base_vaddr
= trunc_page(segs
[0]->p_vaddr
);
550 base_vlimit
= round_page(segs
[1]->p_vaddr
+ segs
[1]->p_memsz
);
551 mapsize
= base_vlimit
- base_vaddr
;
553 ef
= kmalloc(sizeof(struct elf_file
), M_LINKER
, M_WAITOK
| M_ZERO
);
554 #ifdef SPARSE_MAPPING
555 ef
->object
= vm_object_allocate(OBJT_DEFAULT
, mapsize
>> PAGE_SHIFT
);
556 if (ef
->object
== NULL
) {
561 vm_object_reference(ef
->object
);
562 ef
->address
= (caddr_t
)vm_map_min(&kernel_map
);
563 error
= vm_map_find(&kernel_map
, ef
->object
, 0,
564 (vm_offset_t
*)&ef
->address
, mapsize
,
567 VM_PROT_ALL
, VM_PROT_ALL
,
570 vm_object_deallocate(ef
->object
);
575 ef
->address
= kmalloc(mapsize
, M_LINKER
, M_WAITOK
);
577 mapbase
= ef
->address
;
580 * Read the text and data sections and zero the bss.
582 for (i
= 0; i
< 2; i
++) {
583 caddr_t segbase
= mapbase
+ segs
[i
]->p_vaddr
- base_vaddr
;
584 error
= vn_rdwr(UIO_READ
, vp
,
585 segbase
, segs
[i
]->p_filesz
, segs
[i
]->p_offset
,
586 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
588 #ifdef SPARSE_MAPPING
589 vm_map_remove(&kernel_map
, (vm_offset_t
) ef
->address
,
590 (vm_offset_t
) ef
->address
591 + (ef
->object
->size
<< PAGE_SHIFT
));
592 vm_object_deallocate(ef
->object
);
594 kfree(ef
->address
, M_LINKER
);
599 bzero(segbase
+ segs
[i
]->p_filesz
,
600 segs
[i
]->p_memsz
- segs
[i
]->p_filesz
);
602 #ifdef SPARSE_MAPPING
604 * Wire down the pages
606 vm_map_wire(&kernel_map
,
607 (vm_offset_t
) segbase
,
608 (vm_offset_t
) segbase
+ segs
[i
]->p_memsz
,
613 ef
->dynamic
= (const Elf_Dyn
*) (mapbase
+ phdyn
->p_vaddr
- base_vaddr
);
615 lf
= linker_make_file(filename
, ef
, &link_elf_file_ops
);
617 #ifdef SPARSE_MAPPING
618 vm_map_remove(&kernel_map
, (vm_offset_t
) ef
->address
,
619 (vm_offset_t
) ef
->address
620 + (ef
->object
->size
<< PAGE_SHIFT
));
621 vm_object_deallocate(ef
->object
);
623 kfree(ef
->address
, M_LINKER
);
629 lf
->address
= ef
->address
;
632 error
= parse_dynamic(lf
);
635 link_elf_reloc_local(lf
);
636 error
= linker_load_dependencies(lf
);
639 error
= relocate_file(lf
);
643 /* Try and load the symbol table if it's present. (you can strip it!) */
644 nbytes
= hdr
->e_shnum
* hdr
->e_shentsize
;
645 if (nbytes
== 0 || hdr
->e_shoff
== 0)
647 shdr
= kmalloc(nbytes
, M_LINKER
, M_WAITOK
| M_ZERO
);
648 error
= vn_rdwr(UIO_READ
, vp
,
649 (caddr_t
)shdr
, nbytes
, hdr
->e_shoff
,
650 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
655 for (i
= 0; i
< hdr
->e_shnum
; i
++) {
656 if (shdr
[i
].sh_type
== SHT_SYMTAB
) {
658 symstrindex
= shdr
[i
].sh_link
;
661 if (symtabindex
< 0 || symstrindex
< 0)
664 symcnt
= shdr
[symtabindex
].sh_size
;
665 ef
->symbase
= kmalloc(symcnt
, M_LINKER
, M_WAITOK
);
666 strcnt
= shdr
[symstrindex
].sh_size
;
667 ef
->strbase
= kmalloc(strcnt
, M_LINKER
, M_WAITOK
);
668 error
= vn_rdwr(UIO_READ
, vp
,
669 ef
->symbase
, symcnt
, shdr
[symtabindex
].sh_offset
,
670 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
673 error
= vn_rdwr(UIO_READ
, vp
,
674 ef
->strbase
, strcnt
, shdr
[symstrindex
].sh_offset
,
675 UIO_SYSSPACE
, IO_NODELOCKED
, p
->p_ucred
, &resid
);
679 ef
->ddbsymcnt
= symcnt
/ sizeof(Elf_Sym
);
680 ef
->ddbsymtab
= (const Elf_Sym
*)ef
->symbase
;
681 ef
->ddbstrcnt
= strcnt
;
682 ef
->ddbstrtab
= ef
->strbase
;
690 linker_file_unload(lf
);
692 kfree(shdr
, M_LINKER
);
694 kfree(firstpage
, M_LINKER
);
702 elf_relocaddr(linker_file_t lf
, Elf_Addr x
)
708 if (x
>= ef
->pcpu_start
&& x
< ef
->pcpu_stop
)
709 return ((x
- ef
->pcpu_start
) + ef
->pcpu_base
);
711 if (x
>= ef
->vnet_start
&& x
< ef
->vnet_stop
)
712 return ((x
- ef
->vnet_start
) + ef
->vnet_base
);
719 link_elf_unload_file(linker_file_t file
)
721 elf_file_t ef
= file
->priv
;
724 #ifdef SPARSE_MAPPING
726 vm_map_remove(&kernel_map
, (vm_offset_t
) ef
->address
,
727 (vm_offset_t
) ef
->address
728 + (ef
->object
->size
<< PAGE_SHIFT
));
729 vm_object_deallocate(ef
->object
);
733 kfree(ef
->address
, M_LINKER
);
736 kfree(ef
->symbase
, M_LINKER
);
738 kfree(ef
->strbase
, M_LINKER
);
744 link_elf_unload_module(linker_file_t file
)
746 elf_file_t ef
= file
->priv
;
751 preload_delete_name(file
->filename
);
755 symbol_name(elf_file_t ef
, Elf_Size r_info
)
759 if (ELF_R_SYM(r_info
)) {
760 ref
= ef
->symtab
+ ELF_R_SYM(r_info
);
761 return ef
->strtab
+ ref
->st_name
;
767 relocate_file(linker_file_t lf
)
769 elf_file_t ef
= lf
->priv
;
770 const Elf_Rel
*rellim
;
772 const Elf_Rela
*relalim
;
773 const Elf_Rela
*rela
;
776 /* Perform relocations without addend if there are any: */
779 rellim
= (const Elf_Rel
*)((const char *)ef
->rel
+ ef
->relsize
);
780 while (rel
< rellim
) {
781 if (elf_reloc(lf
, (Elf_Addr
)ef
->address
, rel
, ELF_RELOC_REL
, elf_lookup
)) {
782 symname
= symbol_name(ef
, rel
->r_info
);
783 kprintf("link_elf: symbol %s undefined\n", symname
);
790 /* Perform relocations with addend if there are any: */
793 relalim
= (const Elf_Rela
*)((const char *)ef
->rela
+ ef
->relasize
);
794 while (rela
< relalim
) {
795 if (elf_reloc(lf
, (Elf_Addr
)ef
->address
, rela
, ELF_RELOC_RELA
, elf_lookup
)) {
796 symname
= symbol_name(ef
, rela
->r_info
);
797 kprintf("link_elf: symbol %s undefined\n", symname
);
804 /* Perform PLT relocations without addend if there are any: */
807 rellim
= (const Elf_Rel
*)((const char *)ef
->pltrel
+ ef
->pltrelsize
);
808 while (rel
< rellim
) {
809 if (elf_reloc(lf
, (Elf_Addr
)ef
->address
, rel
, ELF_RELOC_REL
, elf_lookup
)) {
810 symname
= symbol_name(ef
, rel
->r_info
);
811 kprintf("link_elf: symbol %s undefined\n", symname
);
818 /* Perform relocations with addend if there are any: */
821 relalim
= (const Elf_Rela
*)((const char *)ef
->pltrela
+ ef
->pltrelasize
);
822 while (rela
< relalim
) {
823 symname
= symbol_name(ef
, rela
->r_info
);
824 if (elf_reloc(lf
, (Elf_Addr
)ef
->address
, rela
, ELF_RELOC_RELA
, elf_lookup
)) {
825 kprintf("link_elf: symbol %s undefined\n", symname
);
836 * Hash function for symbol table lookup. Don't even think about changing
837 * this. It is specified by the System V ABI.
840 elf_hash(const char *name
)
842 const unsigned char *p
= (const unsigned char *) name
;
848 if ((g
= h
& 0xf0000000) != 0)
856 link_elf_lookup_symbol(linker_file_t lf
, const char* name
, c_linker_sym_t
* sym
)
858 elf_file_t ef
= lf
->priv
;
859 unsigned long symnum
;
865 /* If we don't have a hash, bail. */
866 if (ef
->buckets
== NULL
|| ef
->nbuckets
== 0) {
867 kprintf("link_elf_lookup_symbol: missing symbol hash table\n");
871 /* First, search hashed global symbols */
872 hash
= elf_hash(name
);
873 symnum
= ef
->buckets
[hash
% ef
->nbuckets
];
875 while (symnum
!= STN_UNDEF
) {
876 if (symnum
>= ef
->nchains
) {
877 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
881 symp
= ef
->symtab
+ symnum
;
882 if (symp
->st_name
== 0) {
883 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
887 strp
= ef
->strtab
+ symp
->st_name
;
889 if (strcmp(name
, strp
) == 0) {
890 if (symp
->st_shndx
!= SHN_UNDEF
||
891 (symp
->st_value
!= 0 &&
892 ELF_ST_TYPE(symp
->st_info
) == STT_FUNC
)
894 *sym
= (c_linker_sym_t
) symp
;
901 symnum
= ef
->chains
[symnum
];
904 /* If we have not found it, look at the full table (if loaded) */
905 if (ef
->symtab
== ef
->ddbsymtab
)
908 /* Exhaustive search */
909 for (i
= 0, symp
= ef
->ddbsymtab
; i
< ef
->ddbsymcnt
; i
++, symp
++) {
910 strp
= ef
->ddbstrtab
+ symp
->st_name
;
911 if (strcmp(name
, strp
) == 0) {
912 if (symp
->st_shndx
!= SHN_UNDEF
||
913 (symp
->st_value
!= 0 &&
914 ELF_ST_TYPE(symp
->st_info
) == STT_FUNC
)) {
915 *sym
= (c_linker_sym_t
) symp
;
926 link_elf_symbol_values(linker_file_t lf
, c_linker_sym_t sym
, linker_symval_t
*symval
)
928 elf_file_t ef
= lf
->priv
;
929 const Elf_Sym
*es
= (const Elf_Sym
*)sym
;
931 if (es
>= ef
->symtab
&& ((es
- ef
->symtab
) < ef
->nchains
)) {
932 symval
->name
= ef
->strtab
+ es
->st_name
;
933 symval
->value
= (caddr_t
) ef
->address
+ es
->st_value
;
934 symval
->size
= es
->st_size
;
937 if (ef
->symtab
== ef
->ddbsymtab
)
939 if (es
>= ef
->ddbsymtab
&& ((es
- ef
->ddbsymtab
) < ef
->ddbsymcnt
)) {
940 symval
->name
= ef
->ddbstrtab
+ es
->st_name
;
941 symval
->value
= (caddr_t
) ef
->address
+ es
->st_value
;
942 symval
->size
= es
->st_size
;
949 link_elf_search_symbol(linker_file_t lf
, caddr_t value
,
950 c_linker_sym_t
*sym
, long *diffp
)
952 elf_file_t ef
= lf
->priv
;
953 u_long off
= (uintptr_t)(void *)value
;
957 const Elf_Sym
*best
= 0;
960 for (i
= 0, es
= ef
->ddbsymtab
; i
< ef
->ddbsymcnt
; i
++, es
++) {
961 if (es
->st_name
== 0)
963 st_value
= es
->st_value
+ (uintptr_t)(void *)ef
->address
;
964 if (off
>= st_value
) {
965 if (off
- st_value
< diff
) {
966 diff
= off
- st_value
;
970 } else if (off
- st_value
== diff
) {
979 *sym
= (c_linker_sym_t
) best
;
985 * Look up a linker set on an ELF system.
988 link_elf_lookup_set(linker_file_t lf
, const char *name
,
989 void ***startp
, void ***stopp
, int *countp
)
992 linker_symval_t symval
;
994 void **start
, **stop
;
995 int len
, error
= 0, count
;
997 len
= strlen(name
) + sizeof("__start_set_"); /* sizeof includes \0 */
998 setsym
= kmalloc(len
, M_LINKER
, M_WAITOK
);
1000 /* get address of first entry */
1001 ksnprintf(setsym
, len
, "%s%s", "__start_set_", name
);
1002 error
= link_elf_lookup_symbol(lf
, setsym
, &sym
);
1005 link_elf_symbol_values(lf
, sym
, &symval
);
1006 if (symval
.value
== 0) {
1010 start
= (void **)symval
.value
;
1012 /* get address of last entry */
1013 ksnprintf(setsym
, len
, "%s%s", "__stop_set_", name
);
1014 error
= link_elf_lookup_symbol(lf
, setsym
, &sym
);
1017 link_elf_symbol_values(lf
, sym
, &symval
);
1018 if (symval
.value
== 0) {
1022 stop
= (void **)symval
.value
;
1024 /* and the number of entries */
1025 count
= stop
- start
;
1036 kfree(setsym
, M_LINKER
);
1041 * Symbol lookup function that can be used when the symbol index is known (ie
1042 * in relocations). It uses the symbol index instead of doing a fully fledged
1043 * hash table based lookup when such is valid. For example for local symbols.
1044 * This is not only more efficient, it's also more correct. It's not always
1045 * the case that the symbol can be found through the hash table.
1048 elf_lookup(linker_file_t lf
, Elf_Size symidx
, int deps
, Elf_Addr
*result
)
1050 elf_file_t ef
= lf
->priv
;
1054 /* Don't even try to lookup the symbol if the index is bogus. */
1055 if (symidx
>= ef
->nchains
)
1058 sym
= ef
->symtab
+ symidx
;
1061 * Don't do a full lookup when the symbol is local. It may even
1062 * fail because it may not be found through the hash table.
1064 if (ELF_ST_BIND(sym
->st_info
) == STB_LOCAL
) {
1065 /* Force lookup failure when we have an insanity. */
1066 if (sym
->st_shndx
== SHN_UNDEF
|| sym
->st_value
== 0)
1068 return ((Elf_Addr
) ef
->address
+ sym
->st_value
);
1071 * XXX we can avoid doing a hash table based lookup for global
1072 * symbols as well. This however is not always valid, so we'll
1073 * just do it the hard way for now. Performance tweaks can
1077 symbol
= ef
->strtab
+ sym
->st_name
;
1079 /* Force a lookup failure if the symbol name is bogus. */
1083 return (linker_file_lookup_symbol(lf
, symbol
, deps
, (caddr_t
*)result
));
1086 link_elf_reloc_local(linker_file_t lf
)
1088 elf_file_t ef
= lf
->priv
;
1089 const Elf_Rel
*rellim
;
1091 const Elf_Rela
*relalim
;
1092 const Elf_Rela
*rela
;
1094 /* Perform relocations without addend if there are any: */
1095 if ((rel
= ef
->rel
) != NULL
) {
1096 rellim
= (const Elf_Rel
*)((const char *)ef
->rel
+ ef
->relsize
);
1097 while (rel
< rellim
) {
1098 elf_reloc_local(lf
, (Elf_Addr
)ef
->address
, rel
, ELF_RELOC_REL
,
1104 /* Perform relocations with addend if there are any: */
1105 if ((rela
= ef
->rela
) != NULL
) {
1106 relalim
= (const Elf_Rela
*)((const char *)ef
->rela
+ ef
->relasize
);
1107 while (rela
< relalim
) {
1108 elf_reloc_local(lf
, (Elf_Addr
)ef
->address
, rela
, ELF_RELOC_RELA
,