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 #if defined(__amd64__) && defined(_KERNEL_VIRTUAL)
57 static int link_elf_preload_file(const char *, linker_file_t *);
58 static int link_elf_preload_finish(linker_file_t);
59 static int link_elf_load_file(const char*, linker_file_t*);
60 static int link_elf_lookup_symbol(linker_file_t, const char*,
62 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
63 static int link_elf_search_symbol(linker_file_t, caddr_t value,
64 c_linker_sym_t* sym, long* diffp);
66 static void link_elf_unload_file(linker_file_t);
67 static void link_elf_unload_module(linker_file_t);
68 static int link_elf_lookup_set(linker_file_t, const char *,
69 void ***, void ***, int *);
70 static int elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *);
71 static void link_elf_reloc_local(linker_file_t lf);
73 static struct linker_class_ops link_elf_class_ops = {
75 link_elf_preload_file,
78 static struct linker_file_ops link_elf_file_ops = {
79 .lookup_symbol = link_elf_lookup_symbol,
80 .symbol_values = link_elf_symbol_values,
81 .search_symbol = link_elf_search_symbol,
82 .unload = link_elf_unload_file,
83 .lookup_set = link_elf_lookup_set
86 static struct linker_file_ops link_elf_module_ops = {
87 .lookup_symbol = link_elf_lookup_symbol,
88 .symbol_values = link_elf_symbol_values,
89 .search_symbol = link_elf_search_symbol,
90 .preload_finish = link_elf_preload_finish,
91 .unload = link_elf_unload_module,
92 .lookup_set = link_elf_lookup_set,
95 typedef struct elf_file {
96 caddr_t address; /* Relocation address */
98 vm_object_t object; /* VM object to hold file pages */
100 const Elf_Dyn* dynamic; /* Symbol table etc. */
101 Elf_Hashelt nbuckets; /* DT_HASH info */
103 const Elf_Hashelt* buckets;
104 const Elf_Hashelt* chains;
106 caddr_t strtab; /* DT_STRTAB */
107 int strsz; /* DT_STRSZ */
108 const Elf_Sym* symtab; /* DT_SYMTAB */
109 Elf_Addr* got; /* DT_PLTGOT */
110 const Elf_Rel* pltrel; /* DT_JMPREL */
111 int pltrelsize; /* DT_PLTRELSZ */
112 const Elf_Rela* pltrela; /* DT_JMPREL */
113 int pltrelasize; /* DT_PLTRELSZ */
114 const Elf_Rel* rel; /* DT_REL */
115 int relsize; /* DT_RELSZ */
116 const Elf_Rela* rela; /* DT_RELA */
117 int relasize; /* DT_RELASZ */
119 const Elf_Sym* ddbsymtab; /* The symbol table we are using */
120 long ddbsymcnt; /* Number of symbols */
121 caddr_t ddbstrtab; /* String table */
122 long ddbstrcnt; /* number of bytes in string table */
123 caddr_t symbase; /* malloc'ed symbold base */
124 caddr_t strbase; /* malloc'ed string base */
127 static int parse_dynamic(linker_file_t lf);
128 static int relocate_file(linker_file_t lf);
129 static int parse_module_symbols(linker_file_t lf);
132 * The kernel symbol table starts here.
134 extern struct _dynamic _DYNAMIC;
137 link_elf_init(void* arg)
140 caddr_t modptr, baseptr, sizeptr;
144 #if ELF_TARG_CLASS == ELFCLASS32
145 linker_add_class("elf32", NULL, &link_elf_class_ops);
147 linker_add_class("elf64", NULL, &link_elf_class_ops);
150 dp = (Elf_Dyn*) &_DYNAMIC;
152 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_INTWAIT | M_ZERO);
154 #ifdef SPARSE_MAPPING
159 modptr = preload_search_by_type("elf kernel");
161 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
164 linker_kernel_file = linker_make_file(modname, ef, &link_elf_file_ops);
165 if (linker_kernel_file == NULL)
166 panic("link_elf_init: Can't create linker structures for kernel");
167 parse_dynamic(linker_kernel_file);
168 #if defined(__amd64__) && defined(_KERNEL_VIRTUAL)
169 fprintf(stderr, "WARNING: KERNBASE being used\n");
171 linker_kernel_file->address = (caddr_t) KERNBASE;
172 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
176 baseptr = preload_search_info(modptr, MODINFO_ADDR);
178 linker_kernel_file->address = *(caddr_t *)baseptr;
179 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
181 linker_kernel_file->size = *(size_t *)sizeptr;
183 parse_module_symbols(linker_kernel_file);
184 linker_current_file = linker_kernel_file;
185 linker_kernel_file->flags |= LINKER_FILE_LINKED;
189 SYSINIT(link_elf, SI_BOOT2_KLD, SI_ORDER_SECOND, link_elf_init, 0);
192 parse_module_symbols(linker_file_t lf)
194 elf_file_t ef = lf->priv;
196 caddr_t ssym, esym, base;
202 if (ef->modptr == NULL)
204 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
207 ssym = *(caddr_t *)pointer;
208 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
211 esym = *(caddr_t *)pointer;
215 symcnt = *(long *)base;
216 base += sizeof(long);
217 symtab = (Elf_Sym *)base;
218 base += roundup(symcnt, sizeof(long));
220 if (base > esym || base < ssym) {
221 kprintf("Symbols are corrupt!\n");
225 strcnt = *(long *)base;
226 base += sizeof(long);
228 base += roundup(strcnt, sizeof(long));
230 if (base > esym || base < ssym) {
231 kprintf("Symbols are corrupt!\n");
235 ef->ddbsymtab = symtab;
236 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
237 ef->ddbstrtab = strtab;
238 ef->ddbstrcnt = strcnt;
244 parse_dynamic(linker_file_t lf)
246 elf_file_t ef = lf->priv;
248 int plttype = DT_REL;
250 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
254 /* From src/libexec/rtld-elf/rtld.c */
255 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
256 (ef->address + dp->d_un.d_ptr);
257 ef->nbuckets = hashtab[0];
258 ef->nchains = hashtab[1];
259 ef->buckets = hashtab + 2;
260 ef->chains = ef->buckets + ef->nbuckets;
264 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
267 ef->strsz = dp->d_un.d_val;
270 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
273 if (dp->d_un.d_val != sizeof(Elf_Sym))
277 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
280 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
283 ef->relsize = dp->d_un.d_val;
286 if (dp->d_un.d_val != sizeof(Elf_Rel))
290 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
293 ef->pltrelsize = dp->d_un.d_val;
296 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
299 ef->relasize = dp->d_un.d_val;
302 if (dp->d_un.d_val != sizeof(Elf_Rela))
306 plttype = dp->d_un.d_val;
307 if (plttype != DT_REL && plttype != DT_RELA)
313 if (plttype == DT_RELA) {
314 ef->pltrela = (const Elf_Rela *) ef->pltrel;
316 ef->pltrelasize = ef->pltrelsize;
320 ef->ddbsymtab = ef->symtab;
321 ef->ddbsymcnt = ef->nchains;
322 ef->ddbstrtab = ef->strtab;
323 ef->ddbstrcnt = ef->strsz;
329 link_elf_error(const char *s)
331 kprintf("kldload: %s\n", s);
335 link_elf_preload_file(const char *filename, linker_file_t *result)
337 caddr_t modptr, baseptr, sizeptr, dynptr;
345 * Look to see if we have the module preloaded.
347 modptr = preload_search_by_name(filename);
351 /* It's preloaded, check we can handle it and collect information */
352 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
353 baseptr = preload_search_info(modptr, MODINFO_ADDR);
354 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
355 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
357 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
358 strcmp(type, "elf module") != 0))
360 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
363 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
365 ef->address = *(caddr_t *)baseptr;
366 #ifdef SPARSE_MAPPING
369 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
370 ef->dynamic = (Elf_Dyn *)dp;
371 lf = linker_make_file(filename, ef, &link_elf_module_ops);
376 lf->address = ef->address;
377 lf->size = *(size_t *)sizeptr;
379 error = parse_dynamic(lf);
381 linker_file_unload(lf);
384 link_elf_reloc_local(lf);
390 link_elf_preload_finish(linker_file_t lf)
394 error = relocate_file(lf);
397 parse_module_symbols(lf);
403 link_elf_load_file(const char* filename, linker_file_t* result)
405 struct nlookupdata nd;
406 struct thread *td = curthread; /* XXX */
407 struct proc *p = td->td_proc;
422 Elf_Addr base_vlimit;
435 if (p->p_ucred == NULL) {
436 kprintf("link_elf_load_file: cannot load '%s' from filesystem"
437 " this early\n", filename);
442 pathname = linker_search_path(filename);
443 if (pathname == NULL)
446 error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP);
448 error = vn_open(&nd, NULL, FREAD, 0);
449 kfree(pathname, M_LINKER);
455 nd.nl_open_vp = NULL;
459 * Read the elf header from the file.
461 firstpage = kmalloc(PAGE_SIZE, M_LINKER, M_WAITOK);
462 hdr = (Elf_Ehdr *)firstpage;
463 error = vn_rdwr(UIO_READ, vp, firstpage, PAGE_SIZE, 0,
464 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
465 nbytes = PAGE_SIZE - resid;
474 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
475 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
476 link_elf_error("Unsupported file layout");
480 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
481 || hdr->e_version != EV_CURRENT) {
482 link_elf_error("Unsupported file version");
486 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
490 if (hdr->e_machine != ELF_TARG_MACH) {
491 link_elf_error("Unsupported machine");
497 * We rely on the program header being in the first page. This is
498 * not strictly required by the ABI specification, but it seems to
499 * always true in practice. And, it simplifies things considerably.
501 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
502 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
503 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
504 link_elf_error("Unreadable program headers");
507 * Scan the program header entries, and save key information.
509 * We rely on there being exactly two load segments, text and data,
512 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
513 phlimit = phdr + hdr->e_phnum;
517 while (phdr < phlimit) {
518 switch (phdr->p_type) {
522 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_offset = trunc_page(segs[0]->p_offset);
556 base_vaddr = trunc_page(segs[0]->p_vaddr);
557 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
558 mapsize = base_vlimit - base_vaddr;
560 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
561 #ifdef SPARSE_MAPPING
562 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
563 if (ef->object == NULL) {
568 vm_object_reference(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,
577 vm_object_deallocate(ef->object);
582 ef->address = kmalloc(mapsize, M_LINKER, M_WAITOK);
584 mapbase = ef->address;
587 * Read the text and data sections and zero the bss.
589 for (i = 0; i < 2; i++) {
590 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
591 error = vn_rdwr(UIO_READ, vp,
592 segbase, segs[i]->p_filesz, segs[i]->p_offset,
593 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
595 #ifdef SPARSE_MAPPING
596 vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
597 (vm_offset_t) ef->address
598 + (ef->object->size << PAGE_SHIFT));
599 vm_object_deallocate(ef->object);
601 kfree(ef->address, M_LINKER);
606 bzero(segbase + segs[i]->p_filesz,
607 segs[i]->p_memsz - segs[i]->p_filesz);
609 #ifdef SPARSE_MAPPING
611 * Wire down the pages
613 vm_map_wire(&kernel_map,
614 (vm_offset_t) segbase,
615 (vm_offset_t) segbase + segs[i]->p_memsz,
620 ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
622 lf = linker_make_file(filename, ef, &link_elf_file_ops);
624 #ifdef SPARSE_MAPPING
625 vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
626 (vm_offset_t) ef->address
627 + (ef->object->size << PAGE_SHIFT));
628 vm_object_deallocate(ef->object);
630 kfree(ef->address, M_LINKER);
636 lf->address = ef->address;
639 error = parse_dynamic(lf);
642 link_elf_reloc_local(lf);
643 error = linker_load_dependencies(lf);
646 error = relocate_file(lf);
650 /* Try and load the symbol table if it's present. (you can strip it!) */
651 nbytes = hdr->e_shnum * hdr->e_shentsize;
652 if (nbytes == 0 || hdr->e_shoff == 0)
654 shdr = kmalloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
655 error = vn_rdwr(UIO_READ, vp,
656 (caddr_t)shdr, nbytes, hdr->e_shoff,
657 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
662 for (i = 0; i < hdr->e_shnum; i++) {
663 if (shdr[i].sh_type == SHT_SYMTAB) {
665 symstrindex = shdr[i].sh_link;
668 if (symtabindex < 0 || symstrindex < 0)
671 symcnt = shdr[symtabindex].sh_size;
672 ef->symbase = kmalloc(symcnt, M_LINKER, M_WAITOK);
673 strcnt = shdr[symstrindex].sh_size;
674 ef->strbase = kmalloc(strcnt, M_LINKER, M_WAITOK);
675 error = vn_rdwr(UIO_READ, vp,
676 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
677 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
680 error = vn_rdwr(UIO_READ, vp,
681 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
682 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
686 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
687 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
688 ef->ddbstrcnt = strcnt;
689 ef->ddbstrtab = ef->strbase;
697 linker_file_unload(lf);
699 kfree(shdr, M_LINKER);
701 kfree(firstpage, M_LINKER);
709 elf_relocaddr(linker_file_t lf, Elf_Addr x)
715 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
716 return ((x - ef->pcpu_start) + ef->pcpu_base);
718 if (x >= ef->vnet_start && x < ef->vnet_stop)
719 return ((x - ef->vnet_start) + ef->vnet_base);
726 link_elf_unload_file(linker_file_t file)
728 elf_file_t ef = file->priv;
731 #ifdef SPARSE_MAPPING
733 vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
734 (vm_offset_t) ef->address
735 + (ef->object->size << PAGE_SHIFT));
736 vm_object_deallocate(ef->object);
740 kfree(ef->address, M_LINKER);
743 kfree(ef->symbase, M_LINKER);
745 kfree(ef->strbase, M_LINKER);
751 link_elf_unload_module(linker_file_t file)
753 elf_file_t ef = file->priv;
758 preload_delete_name(file->filename);
762 symbol_name(elf_file_t ef, Elf_Size r_info)
766 if (ELF_R_SYM(r_info)) {
767 ref = ef->symtab + ELF_R_SYM(r_info);
768 return ef->strtab + ref->st_name;
774 relocate_file(linker_file_t lf)
776 elf_file_t ef = lf->priv;
777 const Elf_Rel *rellim;
779 const Elf_Rela *relalim;
780 const Elf_Rela *rela;
783 /* Perform relocations without addend if there are any: */
786 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
787 while (rel < rellim) {
788 if (elf_reloc(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, elf_lookup)) {
789 symname = symbol_name(ef, rel->r_info);
790 kprintf("link_elf: symbol %s undefined\n", symname);
797 /* Perform relocations with addend if there are any: */
800 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
801 while (rela < relalim) {
802 if (elf_reloc(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, elf_lookup)) {
803 symname = symbol_name(ef, rela->r_info);
804 kprintf("link_elf: symbol %s undefined\n", symname);
811 /* Perform PLT relocations without addend if there are any: */
814 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
815 while (rel < rellim) {
816 if (elf_reloc(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, elf_lookup)) {
817 symname = symbol_name(ef, rel->r_info);
818 kprintf("link_elf: symbol %s undefined\n", symname);
825 /* Perform relocations with addend if there are any: */
828 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
829 while (rela < relalim) {
830 symname = symbol_name(ef, rela->r_info);
831 if (elf_reloc(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, elf_lookup)) {
832 kprintf("link_elf: symbol %s undefined\n", symname);
843 * Hash function for symbol table lookup. Don't even think about changing
844 * this. It is specified by the System V ABI.
847 elf_hash(const char *name)
849 const unsigned char *p = (const unsigned char *) name;
855 if ((g = h & 0xf0000000) != 0)
863 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
865 elf_file_t ef = lf->priv;
866 unsigned long symnum;
872 /* If we don't have a hash, bail. */
873 if (ef->buckets == NULL || ef->nbuckets == 0) {
874 kprintf("link_elf_lookup_symbol: missing symbol hash table\n");
878 /* First, search hashed global symbols */
879 hash = elf_hash(name);
880 symnum = ef->buckets[hash % ef->nbuckets];
882 while (symnum != STN_UNDEF) {
883 if (symnum >= ef->nchains) {
884 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
888 symp = ef->symtab + symnum;
889 if (symp->st_name == 0) {
890 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
894 strp = ef->strtab + symp->st_name;
896 if (strcmp(name, strp) == 0) {
897 if (symp->st_shndx != SHN_UNDEF ||
898 (symp->st_value != 0 &&
899 ELF_ST_TYPE(symp->st_info) == STT_FUNC)
901 *sym = (c_linker_sym_t) symp;
908 symnum = ef->chains[symnum];
911 /* If we have not found it, look at the full table (if loaded) */
912 if (ef->symtab == ef->ddbsymtab)
915 /* Exhaustive search */
916 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
917 strp = ef->ddbstrtab + symp->st_name;
918 if (strcmp(name, strp) == 0) {
919 if (symp->st_shndx != SHN_UNDEF ||
920 (symp->st_value != 0 &&
921 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
922 *sym = (c_linker_sym_t) symp;
933 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t *symval)
935 elf_file_t ef = lf->priv;
936 const Elf_Sym *es = (const Elf_Sym *)sym;
938 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) {
939 symval->name = ef->strtab + es->st_name;
940 symval->value = (caddr_t) ef->address + es->st_value;
941 symval->size = es->st_size;
944 if (ef->symtab == ef->ddbsymtab)
946 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) {
947 symval->name = ef->ddbstrtab + es->st_name;
948 symval->value = (caddr_t) ef->address + es->st_value;
949 symval->size = es->st_size;
956 link_elf_search_symbol(linker_file_t lf, caddr_t value,
957 c_linker_sym_t *sym, long *diffp)
959 elf_file_t ef = lf->priv;
960 u_long off = (uintptr_t)(void *)value;
964 const Elf_Sym *best = 0;
967 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
968 if (es->st_name == 0)
970 st_value = es->st_value + (uintptr_t)(void *)ef->address;
971 if (off >= st_value) {
972 if (off - st_value < diff) {
973 diff = off - st_value;
977 } else if (off - st_value == diff) {
986 *sym = (c_linker_sym_t) best;
992 * Look up a linker set on an ELF system.
995 link_elf_lookup_set(linker_file_t lf, const char *name,
996 void ***startp, void ***stopp, int *countp)
999 linker_symval_t symval;
1001 void **start, **stop;
1002 int len, error = 0, count;
1004 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1005 setsym = kmalloc(len, M_LINKER, M_WAITOK);
1007 /* get address of first entry */
1008 ksnprintf(setsym, len, "%s%s", "__start_set_", name);
1009 error = link_elf_lookup_symbol(lf, setsym, &sym);
1012 link_elf_symbol_values(lf, sym, &symval);
1013 if (symval.value == 0) {
1017 start = (void **)symval.value;
1019 /* get address of last entry */
1020 ksnprintf(setsym, len, "%s%s", "__stop_set_", name);
1021 error = link_elf_lookup_symbol(lf, setsym, &sym);
1024 link_elf_symbol_values(lf, sym, &symval);
1025 if (symval.value == 0) {
1029 stop = (void **)symval.value;
1031 /* and the number of entries */
1032 count = stop - start;
1043 kfree(setsym, M_LINKER);
1048 * Symbol lookup function that can be used when the symbol index is known (ie
1049 * in relocations). It uses the symbol index instead of doing a fully fledged
1050 * hash table based lookup when such is valid. For example for local symbols.
1051 * This is not only more efficient, it's also more correct. It's not always
1052 * the case that the symbol can be found through the hash table.
1055 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *result)
1057 elf_file_t ef = lf->priv;
1061 /* Don't even try to lookup the symbol if the index is bogus. */
1062 if (symidx >= ef->nchains)
1065 sym = ef->symtab + symidx;
1068 * Don't do a full lookup when the symbol is local. It may even
1069 * fail because it may not be found through the hash table.
1071 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1072 /* Force lookup failure when we have an insanity. */
1073 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1075 return ((Elf_Addr) ef->address + sym->st_value);
1078 * XXX we can avoid doing a hash table based lookup for global
1079 * symbols as well. This however is not always valid, so we'll
1080 * just do it the hard way for now. Performance tweaks can
1084 symbol = ef->strtab + sym->st_name;
1086 /* Force a lookup failure if the symbol name is bogus. */
1090 return (linker_file_lookup_symbol(lf, symbol, deps, (caddr_t *)result));
1093 link_elf_reloc_local(linker_file_t lf)
1095 elf_file_t ef = lf->priv;
1096 const Elf_Rel *rellim;
1098 const Elf_Rela *relalim;
1099 const Elf_Rela *rela;
1101 /* Perform relocations without addend if there are any: */
1102 if ((rel = ef->rel) != NULL) {
1103 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1104 while (rel < rellim) {
1105 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1111 /* Perform relocations with addend if there are any: */
1112 if ((rela = ef->rela) != NULL) {
1113 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1114 while (rela < relalim) {
1115 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,