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_map.h>
47 #if defined(__x86_64__) && defined(_KERNEL_VIRTUAL)
51 static int link_elf_preload_file(const char *, linker_file_t *);
52 static int link_elf_preload_finish(linker_file_t);
53 static int link_elf_load_file(const char*, linker_file_t*);
54 static int link_elf_lookup_symbol(linker_file_t, const char*,
56 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
57 static int link_elf_search_symbol(linker_file_t, caddr_t value,
58 c_linker_sym_t* sym, long* diffp);
60 static void link_elf_unload_file(linker_file_t);
61 static void link_elf_unload_module(linker_file_t);
62 static int link_elf_lookup_set(linker_file_t, const char *,
63 void ***, void ***, int *);
64 static int elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *);
65 static void link_elf_reloc_local(linker_file_t lf);
67 static struct linker_class_ops link_elf_class_ops = {
69 link_elf_preload_file,
72 static struct linker_file_ops link_elf_file_ops = {
73 .lookup_symbol = link_elf_lookup_symbol,
74 .symbol_values = link_elf_symbol_values,
75 .search_symbol = link_elf_search_symbol,
76 .unload = link_elf_unload_file,
77 .lookup_set = link_elf_lookup_set
80 static struct linker_file_ops link_elf_module_ops = {
81 .lookup_symbol = link_elf_lookup_symbol,
82 .symbol_values = link_elf_symbol_values,
83 .search_symbol = link_elf_search_symbol,
84 .preload_finish = link_elf_preload_finish,
85 .unload = link_elf_unload_module,
86 .lookup_set = link_elf_lookup_set,
89 typedef struct elf_file {
90 caddr_t address; /* Relocation address */
91 const Elf_Dyn* dynamic; /* Symbol table etc. */
92 Elf_Hashelt nbuckets; /* DT_HASH info */
94 const Elf_Hashelt* buckets;
95 const Elf_Hashelt* chains;
97 caddr_t strtab; /* DT_STRTAB */
98 int strsz; /* DT_STRSZ */
99 const Elf_Sym* symtab; /* DT_SYMTAB */
100 Elf_Addr* got; /* DT_PLTGOT */
101 const Elf_Rel* pltrel; /* DT_JMPREL */
102 int pltrelsize; /* DT_PLTRELSZ */
103 const Elf_Rela* pltrela; /* DT_JMPREL */
104 int pltrelasize; /* DT_PLTRELSZ */
105 const Elf_Rel* rel; /* DT_REL */
106 int relsize; /* DT_RELSZ */
107 const Elf_Rela* rela; /* DT_RELA */
108 int relasize; /* DT_RELASZ */
110 const Elf_Sym* ddbsymtab; /* The symbol table we are using */
111 long ddbsymcnt; /* Number of symbols */
112 caddr_t ddbstrtab; /* String table */
113 long ddbstrcnt; /* number of bytes in string table */
114 caddr_t symbase; /* malloc'ed symbold base */
115 caddr_t strbase; /* malloc'ed string base */
118 static int parse_dynamic(linker_file_t lf);
119 static int relocate_file(linker_file_t lf);
120 static int parse_module_symbols(linker_file_t lf);
123 * The kernel symbol table starts here.
125 extern struct _dynamic _DYNAMIC;
128 link_elf_init(void* arg)
131 caddr_t modptr, baseptr, sizeptr;
135 #if ELF_TARG_CLASS == ELFCLASS32
136 linker_add_class("elf32", NULL, &link_elf_class_ops);
138 linker_add_class("elf64", NULL, &link_elf_class_ops);
141 dp = (Elf_Dyn*) &_DYNAMIC;
143 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_INTWAIT | M_ZERO);
147 modptr = preload_search_by_type("elf kernel");
149 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
152 linker_kernel_file = linker_make_file(modname, ef, &link_elf_file_ops);
153 if (linker_kernel_file == NULL)
154 panic("link_elf_init: Can't create linker structures for kernel");
155 parse_dynamic(linker_kernel_file);
156 #if defined(__x86_64__) && defined(_KERNEL_VIRTUAL)
157 fprintf(stderr, "WARNING: KERNBASE being used\n");
159 linker_kernel_file->address = (caddr_t) KERNBASE;
160 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
164 baseptr = preload_search_info(modptr, MODINFO_ADDR);
166 linker_kernel_file->address = *(caddr_t *)baseptr;
167 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
169 linker_kernel_file->size = *(size_t *)sizeptr;
171 parse_module_symbols(linker_kernel_file);
172 linker_current_file = linker_kernel_file;
173 linker_kernel_file->flags |= LINKER_FILE_LINKED;
177 SYSINIT(link_elf, SI_BOOT2_KLD, SI_ORDER_SECOND, link_elf_init, 0);
180 parse_module_symbols(linker_file_t lf)
182 elf_file_t ef = lf->priv;
184 caddr_t ssym, esym, base;
190 if (ef->modptr == NULL)
192 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
195 ssym = *(caddr_t *)pointer;
196 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
199 esym = *(caddr_t *)pointer;
203 symcnt = *(long *)base;
204 base += sizeof(long);
205 symtab = (Elf_Sym *)base;
206 base += roundup(symcnt, sizeof(long));
208 if (base > esym || base < ssym) {
209 kprintf("Symbols are corrupt!\n");
213 strcnt = *(long *)base;
214 base += sizeof(long);
216 base += roundup(strcnt, sizeof(long));
218 if (base > esym || base < ssym) {
219 kprintf("Symbols are corrupt!\n");
223 ef->ddbsymtab = symtab;
224 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
225 ef->ddbstrtab = strtab;
226 ef->ddbstrcnt = strcnt;
232 parse_dynamic(linker_file_t lf)
234 elf_file_t ef = lf->priv;
236 int plttype = DT_REL;
238 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
242 /* From src/libexec/rtld-elf/rtld.c */
243 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
244 (ef->address + dp->d_un.d_ptr);
245 ef->nbuckets = hashtab[0];
246 ef->nchains = hashtab[1];
247 ef->buckets = hashtab + 2;
248 ef->chains = ef->buckets + ef->nbuckets;
252 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
255 ef->strsz = dp->d_un.d_val;
258 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
261 if (dp->d_un.d_val != sizeof(Elf_Sym))
265 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
268 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
271 ef->relsize = dp->d_un.d_val;
274 if (dp->d_un.d_val != sizeof(Elf_Rel))
278 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
281 ef->pltrelsize = dp->d_un.d_val;
284 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
287 ef->relasize = dp->d_un.d_val;
290 if (dp->d_un.d_val != sizeof(Elf_Rela))
294 plttype = dp->d_un.d_val;
295 if (plttype != DT_REL && plttype != DT_RELA)
301 if (plttype == DT_RELA) {
302 ef->pltrela = (const Elf_Rela *) ef->pltrel;
304 ef->pltrelasize = ef->pltrelsize;
308 ef->ddbsymtab = ef->symtab;
309 ef->ddbsymcnt = ef->nchains;
310 ef->ddbstrtab = ef->strtab;
311 ef->ddbstrcnt = ef->strsz;
317 link_elf_error(const char *s)
319 kprintf("kldload: %s\n", s);
323 link_elf_preload_file(const char *filename, linker_file_t *result)
325 caddr_t modptr, baseptr, sizeptr, dynptr;
333 * Look to see if we have the module preloaded.
335 modptr = preload_search_by_name(filename);
339 /* It's preloaded, check we can handle it and collect information */
340 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
341 baseptr = preload_search_info(modptr, MODINFO_ADDR);
342 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
343 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
345 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
346 strcmp(type, "elf module") != 0))
348 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
351 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
353 ef->address = *(caddr_t *)baseptr;
354 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
355 ef->dynamic = (Elf_Dyn *)dp;
356 lf = linker_make_file(filename, ef, &link_elf_module_ops);
361 lf->address = ef->address;
362 lf->size = *(size_t *)sizeptr;
364 error = parse_dynamic(lf);
366 linker_file_unload(lf);
369 link_elf_reloc_local(lf);
375 link_elf_preload_finish(linker_file_t lf)
379 error = relocate_file(lf);
382 parse_module_symbols(lf);
388 link_elf_load_file(const char* filename, linker_file_t* result)
390 struct nlookupdata nd;
391 struct thread *td = curthread; /* XXX */
392 struct proc *p = td->td_proc;
405 Elf_Addr base_vlimit;
417 /* XXX Hack for firmware loading where p == NULL */
423 if (p->p_ucred == NULL) {
424 kprintf("link_elf_load_file: cannot load '%s' from filesystem"
425 " this early\n", filename);
430 pathname = linker_search_path(filename);
431 if (pathname == NULL)
434 error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP);
436 error = vn_open(&nd, NULL, FREAD, 0);
437 kfree(pathname, M_LINKER);
443 nd.nl_open_vp = NULL;
447 * Read the elf header from the file.
449 firstpage = kmalloc(PAGE_SIZE, M_LINKER, M_WAITOK);
450 hdr = (Elf_Ehdr *)firstpage;
451 error = vn_rdwr(UIO_READ, vp, firstpage, PAGE_SIZE, 0,
452 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
453 nbytes = PAGE_SIZE - resid;
462 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
463 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
464 link_elf_error("Unsupported file layout");
468 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
469 || hdr->e_version != EV_CURRENT) {
470 link_elf_error("Unsupported file version");
474 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
478 if (hdr->e_machine != ELF_TARG_MACH) {
479 link_elf_error("Unsupported machine");
485 * We rely on the program header being in the first page. This is
486 * not strictly required by the ABI specification, but it seems to
487 * always true in practice. And, it simplifies things considerably.
489 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
490 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
491 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
492 link_elf_error("Unreadable program headers");
495 * Scan the program header entries, and save key information.
497 * We rely on there being exactly two load segments, text and data,
500 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
501 phlimit = phdr + hdr->e_phnum;
504 while (phdr < phlimit) {
505 switch (phdr->p_type) {
509 link_elf_error("Too many sections");
532 link_elf_error("Object is not dynamically-linked");
538 * Allocate the entire address space of the object, to stake out our
539 * contiguous region, and to establish the base address for relocation.
541 base_vaddr = trunc_page(segs[0]->p_vaddr);
542 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
543 mapsize = base_vlimit - base_vaddr;
545 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
546 ef->address = kmalloc(mapsize, M_LINKER, M_WAITOK);
547 mapbase = ef->address;
550 * Read the text and data sections and zero the bss.
552 for (i = 0; i < 2; i++) {
553 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
554 error = vn_rdwr(UIO_READ, vp,
555 segbase, segs[i]->p_filesz, segs[i]->p_offset,
556 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
558 kfree(ef->address, M_LINKER);
562 bzero(segbase + segs[i]->p_filesz,
563 segs[i]->p_memsz - segs[i]->p_filesz);
566 ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
568 lf = linker_make_file(filename, ef, &link_elf_file_ops);
570 kfree(ef->address, M_LINKER);
575 lf->address = ef->address;
578 error = parse_dynamic(lf);
581 link_elf_reloc_local(lf);
582 error = linker_load_dependencies(lf);
585 error = relocate_file(lf);
589 /* Try and load the symbol table if it's present. (you can strip it!) */
590 nbytes = hdr->e_shnum * hdr->e_shentsize;
591 if (nbytes == 0 || hdr->e_shoff == 0)
593 shdr = kmalloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
594 error = vn_rdwr(UIO_READ, vp,
595 (caddr_t)shdr, nbytes, hdr->e_shoff,
596 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
601 for (i = 0; i < hdr->e_shnum; i++) {
602 if (shdr[i].sh_type == SHT_SYMTAB) {
604 symstrindex = shdr[i].sh_link;
607 if (symtabindex < 0 || symstrindex < 0)
610 symcnt = shdr[symtabindex].sh_size;
611 ef->symbase = kmalloc(symcnt, M_LINKER, M_WAITOK);
612 strcnt = shdr[symstrindex].sh_size;
613 ef->strbase = kmalloc(strcnt, M_LINKER, M_WAITOK);
614 error = vn_rdwr(UIO_READ, vp,
615 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
616 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
619 error = vn_rdwr(UIO_READ, vp,
620 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
621 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
625 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
626 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
627 ef->ddbstrcnt = strcnt;
628 ef->ddbstrtab = ef->strbase;
636 linker_file_unload(lf);
638 kfree(shdr, M_LINKER);
640 kfree(firstpage, M_LINKER);
642 vn_close(vp, FREAD, NULL);
648 elf_relocaddr(linker_file_t lf, Elf_Addr x)
654 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
655 return ((x - ef->pcpu_start) + ef->pcpu_base);
657 if (x >= ef->vnet_start && x < ef->vnet_stop)
658 return ((x - ef->vnet_start) + ef->vnet_base);
665 link_elf_unload_file(linker_file_t file)
667 elf_file_t ef = file->priv;
671 kfree(ef->address, M_LINKER);
673 kfree(ef->symbase, M_LINKER);
675 kfree(ef->strbase, M_LINKER);
681 link_elf_unload_module(linker_file_t file)
683 elf_file_t ef = file->priv;
688 preload_delete_name(file->filename);
692 symbol_name(elf_file_t ef, Elf_Size r_info)
696 if (ELF_R_SYM(r_info)) {
697 ref = ef->symtab + ELF_R_SYM(r_info);
698 return ef->strtab + ref->st_name;
704 relocate_file(linker_file_t lf)
706 elf_file_t ef = lf->priv;
707 const Elf_Rel *rellim;
709 const Elf_Rela *relalim;
710 const Elf_Rela *rela;
713 /* Perform relocations without addend if there are any: */
716 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
717 while (rel < rellim) {
718 if (elf_reloc(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, elf_lookup)) {
719 symname = symbol_name(ef, rel->r_info);
720 kprintf("link_elf: symbol %s undefined\n", symname);
727 /* Perform relocations with addend if there are any: */
730 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
731 while (rela < relalim) {
732 if (elf_reloc(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, elf_lookup)) {
733 symname = symbol_name(ef, rela->r_info);
734 kprintf("link_elf: symbol %s undefined\n", symname);
741 /* Perform PLT relocations without addend if there are any: */
744 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
745 while (rel < rellim) {
746 if (elf_reloc(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, elf_lookup)) {
747 symname = symbol_name(ef, rel->r_info);
748 kprintf("link_elf: symbol %s undefined\n", symname);
755 /* Perform relocations with addend if there are any: */
758 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
759 while (rela < relalim) {
760 symname = symbol_name(ef, rela->r_info);
761 if (elf_reloc(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, elf_lookup)) {
762 kprintf("link_elf: symbol %s undefined\n", symname);
773 * Hash function for symbol table lookup. Don't even think about changing
774 * this. It is specified by the System V ABI.
777 elf_hash(const char *name)
779 const unsigned char *p = (const unsigned char *) name;
785 if ((g = h & 0xf0000000) != 0)
793 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
795 elf_file_t ef = lf->priv;
796 unsigned long symnum;
802 /* If we don't have a hash, bail. */
803 if (ef->buckets == NULL || ef->nbuckets == 0) {
804 kprintf("link_elf_lookup_symbol: missing symbol hash table\n");
808 /* First, search hashed global symbols */
809 hash = elf_hash(name);
810 symnum = ef->buckets[hash % ef->nbuckets];
812 while (symnum != STN_UNDEF) {
813 if (symnum >= ef->nchains) {
814 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
818 symp = ef->symtab + symnum;
819 if (symp->st_name == 0) {
820 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
824 strp = ef->strtab + symp->st_name;
826 if (strcmp(name, strp) == 0) {
827 if (symp->st_shndx != SHN_UNDEF ||
828 (symp->st_value != 0 &&
829 ELF_ST_TYPE(symp->st_info) == STT_FUNC)
831 *sym = (c_linker_sym_t) symp;
838 symnum = ef->chains[symnum];
841 /* If we have not found it, look at the full table (if loaded) */
842 if (ef->symtab == ef->ddbsymtab)
845 /* Exhaustive search */
846 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
847 strp = ef->ddbstrtab + symp->st_name;
848 if (strcmp(name, strp) == 0) {
849 if (symp->st_shndx != SHN_UNDEF ||
850 (symp->st_value != 0 &&
851 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
852 *sym = (c_linker_sym_t) symp;
863 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t *symval)
865 elf_file_t ef = lf->priv;
866 const Elf_Sym *es = (const Elf_Sym *)sym;
868 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) {
869 symval->name = ef->strtab + es->st_name;
870 symval->value = ef->address + es->st_value;
871 symval->size = es->st_size;
874 if (ef->symtab == ef->ddbsymtab)
876 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) {
877 symval->name = ef->ddbstrtab + es->st_name;
878 symval->value = ef->address + es->st_value;
879 symval->size = es->st_size;
886 link_elf_search_symbol(linker_file_t lf, caddr_t value,
887 c_linker_sym_t *sym, long *diffp)
889 elf_file_t ef = lf->priv;
890 u_long off = (uintptr_t)(void *)value;
894 const Elf_Sym *best = NULL;
897 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
898 if (es->st_name == 0)
900 st_value = es->st_value + (uintptr_t)(void *)ef->address;
901 if (off >= st_value) {
902 if (off - st_value < diff) {
903 diff = off - st_value;
907 } else if (off - st_value == diff) {
916 *sym = (c_linker_sym_t) best;
922 * Look up a linker set on an ELF system.
925 link_elf_lookup_set(linker_file_t lf, const char *name,
926 void ***startp, void ***stopp, int *countp)
929 linker_symval_t symval;
931 void **start, **stop;
932 int len, error = 0, count;
934 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
935 setsym = kmalloc(len, M_LINKER, M_WAITOK);
937 /* get address of first entry */
938 ksnprintf(setsym, len, "%s%s", "__start_set_", name);
939 error = link_elf_lookup_symbol(lf, setsym, &sym);
942 link_elf_symbol_values(lf, sym, &symval);
943 if (symval.value == NULL) {
947 start = (void **)symval.value;
949 /* get address of last entry */
950 ksnprintf(setsym, len, "%s%s", "__stop_set_", name);
951 error = link_elf_lookup_symbol(lf, setsym, &sym);
954 link_elf_symbol_values(lf, sym, &symval);
955 if (symval.value == NULL) {
959 stop = (void **)symval.value;
961 /* and the number of entries */
962 count = stop - start;
973 kfree(setsym, M_LINKER);
978 * Symbol lookup function that can be used when the symbol index is known (ie
979 * in relocations). It uses the symbol index instead of doing a fully fledged
980 * hash table based lookup when such is valid. For example for local symbols.
981 * This is not only more efficient, it's also more correct. It's not always
982 * the case that the symbol can be found through the hash table.
985 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *result)
987 elf_file_t ef = lf->priv;
991 /* Don't even try to lookup the symbol if the index is bogus. */
992 if (symidx >= ef->nchains)
995 sym = ef->symtab + symidx;
998 * Don't do a full lookup when the symbol is local. It may even
999 * fail because it may not be found through the hash table.
1001 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1002 /* Force lookup failure when we have an insanity. */
1003 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1005 return ((Elf_Addr) ef->address + sym->st_value);
1008 * XXX we can avoid doing a hash table based lookup for global
1009 * symbols as well. This however is not always valid, so we'll
1010 * just do it the hard way for now. Performance tweaks can
1014 symbol = ef->strtab + sym->st_name;
1016 /* Force a lookup failure if the symbol name is bogus. */
1020 return (linker_file_lookup_symbol(lf, symbol, deps, (caddr_t *)result));
1023 link_elf_reloc_local(linker_file_t lf)
1025 elf_file_t ef = lf->priv;
1026 const Elf_Rel *rellim;
1028 const Elf_Rela *relalim;
1029 const Elf_Rela *rela;
1031 /* Perform relocations without addend if there are any: */
1032 if ((rel = ef->rel) != NULL) {
1033 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1034 while (rel < rellim) {
1035 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1041 /* Perform relocations with addend if there are any: */
1042 if ((rela = ef->rela) != NULL) {
1043 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1044 while (rela < relalim) {
1045 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,