532 lines
14 KiB
C
532 lines
14 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright 1996, 1997, 1998, 1999 John D. Polstra.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Dynamic linker for ELF.
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*
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* John Polstra <jdp@polstra.com>.
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*/
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#include <sys/param.h>
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#include <sys/mman.h>
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#include <machine/cpufunc.h>
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#include <machine/specialreg.h>
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#include <machine/sysarch.h>
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#include <dlfcn.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "debug.h"
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#include "rtld.h"
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#include "rtld_tls.h"
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/*
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* Process the special R_X86_64_COPY relocations in the main program. These
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* copy data from a shared object into a region in the main program's BSS
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* segment.
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*
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* Returns 0 on success, -1 on failure.
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*/
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int
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do_copy_relocations(Obj_Entry *dstobj)
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{
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const Elf_Rela *relalim;
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const Elf_Rela *rela;
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assert(dstobj->mainprog); /* COPY relocations are invalid elsewhere */
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relalim = (const Elf_Rela *)((const char *) dstobj->rela + dstobj->relasize);
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for (rela = dstobj->rela; rela < relalim; rela++) {
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if (ELF_R_TYPE(rela->r_info) == R_X86_64_COPY) {
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void *dstaddr;
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const Elf_Sym *dstsym;
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const char *name;
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size_t size;
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const void *srcaddr;
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const Elf_Sym *srcsym;
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const Obj_Entry *srcobj, *defobj;
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SymLook req;
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int res;
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dstaddr = (void *)(dstobj->relocbase + rela->r_offset);
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dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
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name = dstobj->strtab + dstsym->st_name;
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size = dstsym->st_size;
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symlook_init(&req, name);
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req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info));
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req.flags = SYMLOOK_EARLY;
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for (srcobj = globallist_next(dstobj); srcobj != NULL;
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srcobj = globallist_next(srcobj)) {
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res = symlook_obj(&req, srcobj);
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if (res == 0) {
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srcsym = req.sym_out;
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defobj = req.defobj_out;
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break;
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}
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}
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if (srcobj == NULL) {
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_rtld_error("Undefined symbol \"%s\" referenced from COPY"
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" relocation in %s", name, dstobj->path);
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return -1;
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}
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srcaddr = (const void *)(defobj->relocbase + srcsym->st_value);
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memcpy(dstaddr, srcaddr, size);
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}
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}
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return 0;
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}
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/* Initialize the special GOT entries. */
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void
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init_pltgot(Obj_Entry *obj)
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{
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if (obj->pltgot != NULL) {
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obj->pltgot[1] = (Elf_Addr) obj;
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obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
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}
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}
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/* Process the non-PLT relocations. */
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int
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reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
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RtldLockState *lockstate)
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{
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const Elf_Rela *relalim;
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const Elf_Rela *rela;
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SymCache *cache;
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const Elf_Sym *def;
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const Obj_Entry *defobj;
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Elf_Addr *where, symval;
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Elf32_Addr *where32;
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int r;
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r = -1;
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symval = 0;
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def = NULL;
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/*
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* The dynamic loader may be called from a thread, we have
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* limited amounts of stack available so we cannot use alloca().
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*/
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if (obj != obj_rtld) {
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cache = calloc(obj->dynsymcount, sizeof(SymCache));
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/* No need to check for NULL here */
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} else
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cache = NULL;
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relalim = (const Elf_Rela *)((const char*)obj->rela + obj->relasize);
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for (rela = obj->rela; rela < relalim; rela++) {
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/*
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* First, resolve symbol for relocations which
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* reference symbols.
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*/
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switch (ELF_R_TYPE(rela->r_info)) {
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case R_X86_64_64:
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case R_X86_64_PC32:
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case R_X86_64_GLOB_DAT:
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case R_X86_64_TPOFF64:
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case R_X86_64_TPOFF32:
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case R_X86_64_DTPMOD64:
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case R_X86_64_DTPOFF64:
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case R_X86_64_DTPOFF32:
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def = find_symdef(ELF_R_SYM(rela->r_info), obj,
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&defobj, flags, cache, lockstate);
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if (def == NULL)
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goto done;
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/*
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* If symbol is IFUNC, only perform relocation
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* when caller allowed it by passing
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* SYMLOOK_IFUNC flag. Skip the relocations
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* otherwise.
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*
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* Also error out in case IFUNC relocations
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* are specified for TLS, which cannot be
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* usefully interpreted.
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*/
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if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
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switch (ELF_R_TYPE(rela->r_info)) {
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case R_X86_64_64:
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case R_X86_64_PC32:
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case R_X86_64_GLOB_DAT:
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if ((flags & SYMLOOK_IFUNC) == 0) {
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obj->non_plt_gnu_ifunc = true;
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continue;
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}
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symval = (Elf_Addr)rtld_resolve_ifunc(
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defobj, def);
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break;
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case R_X86_64_TPOFF64:
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case R_X86_64_TPOFF32:
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case R_X86_64_DTPMOD64:
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case R_X86_64_DTPOFF64:
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case R_X86_64_DTPOFF32:
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_rtld_error("%s: IFUNC for TLS reloc",
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obj->path);
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goto done;
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}
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} else {
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if ((flags & SYMLOOK_IFUNC) != 0)
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continue;
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symval = (Elf_Addr)defobj->relocbase +
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def->st_value;
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}
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break;
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default:
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if ((flags & SYMLOOK_IFUNC) != 0)
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continue;
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break;
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}
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where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
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where32 = (Elf32_Addr *)where;
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switch (ELF_R_TYPE(rela->r_info)) {
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case R_X86_64_NONE:
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break;
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case R_X86_64_64:
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*where = symval + rela->r_addend;
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break;
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case R_X86_64_PC32:
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/*
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* I don't think the dynamic linker should
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* ever see this type of relocation. But the
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* binutils-2.6 tools sometimes generate it.
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*/
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*where32 = (Elf32_Addr)(unsigned long)(symval +
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rela->r_addend - (Elf_Addr)where);
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break;
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/* missing: R_X86_64_GOT32 R_X86_64_PLT32 */
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case R_X86_64_COPY:
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/*
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* These are deferred until all other relocations have
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* been done. All we do here is make sure that the COPY
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* relocation is not in a shared library. They are
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* allowed only in executable files.
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*/
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if (!obj->mainprog) {
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_rtld_error("%s: Unexpected R_X86_64_COPY "
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"relocation in shared library", obj->path);
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goto done;
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}
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break;
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case R_X86_64_GLOB_DAT:
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*where = symval;
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break;
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case R_X86_64_TPOFF64:
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/*
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* We lazily allocate offsets for static TLS
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* as we see the first relocation that
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* references the TLS block. This allows us to
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* support (small amounts of) static TLS in
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* dynamically loaded modules. If we run out
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* of space, we generate an error.
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*/
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if (!defobj->tls_done) {
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if (!allocate_tls_offset(
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__DECONST(Obj_Entry *, defobj))) {
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_rtld_error("%s: No space available "
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"for static Thread Local Storage",
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obj->path);
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goto done;
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}
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}
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*where = (Elf_Addr)(def->st_value - defobj->tlsoffset +
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rela->r_addend);
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break;
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case R_X86_64_TPOFF32:
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/*
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* We lazily allocate offsets for static TLS
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* as we see the first relocation that
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* references the TLS block. This allows us to
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* support (small amounts of) static TLS in
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* dynamically loaded modules. If we run out
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* of space, we generate an error.
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*/
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if (!defobj->tls_done) {
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if (!allocate_tls_offset(
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__DECONST(Obj_Entry *, defobj))) {
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_rtld_error("%s: No space available "
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"for static Thread Local Storage",
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obj->path);
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goto done;
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}
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}
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*where32 = (Elf32_Addr)(def->st_value -
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defobj->tlsoffset + rela->r_addend);
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break;
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case R_X86_64_DTPMOD64:
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*where += (Elf_Addr)defobj->tlsindex;
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break;
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case R_X86_64_DTPOFF64:
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*where += (Elf_Addr)(def->st_value + rela->r_addend);
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break;
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case R_X86_64_DTPOFF32:
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*where32 += (Elf32_Addr)(def->st_value +
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rela->r_addend);
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break;
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case R_X86_64_RELATIVE:
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*where = (Elf_Addr)(obj->relocbase + rela->r_addend);
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break;
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/*
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* missing:
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* R_X86_64_GOTPCREL, R_X86_64_32, R_X86_64_32S, R_X86_64_16,
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* R_X86_64_PC16, R_X86_64_8, R_X86_64_PC8
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*/
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default:
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_rtld_error("%s: Unsupported relocation type %u"
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" in non-PLT relocations\n", obj->path,
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(unsigned int)ELF_R_TYPE(rela->r_info));
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goto done;
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}
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}
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r = 0;
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done:
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free(cache);
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return (r);
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}
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/* Process the PLT relocations. */
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int
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reloc_plt(Obj_Entry *obj)
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{
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const Elf_Rela *relalim;
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const Elf_Rela *rela;
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relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize);
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for (rela = obj->pltrela; rela < relalim; rela++) {
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Elf_Addr *where;
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switch(ELF_R_TYPE(rela->r_info)) {
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case R_X86_64_JMP_SLOT:
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/* Relocate the GOT slot pointing into the PLT. */
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where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
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*where += (Elf_Addr)obj->relocbase;
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break;
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case R_X86_64_IRELATIVE:
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obj->irelative = true;
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break;
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default:
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_rtld_error("Unknown relocation type %x in PLT",
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(unsigned int)ELF_R_TYPE(rela->r_info));
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return (-1);
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}
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}
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return 0;
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}
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/* Relocate the jump slots in an object. */
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int
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reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
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{
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const Elf_Rela *relalim;
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const Elf_Rela *rela;
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if (obj->jmpslots_done)
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return 0;
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relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize);
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for (rela = obj->pltrela; rela < relalim; rela++) {
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Elf_Addr *where, target;
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const Elf_Sym *def;
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const Obj_Entry *defobj;
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switch (ELF_R_TYPE(rela->r_info)) {
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case R_X86_64_JMP_SLOT:
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where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
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def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
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SYMLOOK_IN_PLT | flags, NULL, lockstate);
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if (def == NULL)
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return (-1);
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if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
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obj->gnu_ifunc = true;
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continue;
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}
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target = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend);
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reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela);
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break;
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case R_X86_64_IRELATIVE:
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break;
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default:
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_rtld_error("Unknown relocation type %x in PLT",
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(unsigned int)ELF_R_TYPE(rela->r_info));
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return (-1);
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}
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}
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obj->jmpslots_done = true;
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return 0;
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}
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/* Fixup the jump slot at "where" to transfer control to "target". */
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Elf_Addr
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reloc_jmpslot(Elf_Addr *where, Elf_Addr target,
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const struct Struct_Obj_Entry *obj __unused,
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const struct Struct_Obj_Entry *refobj __unused,
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const Elf_Rel *rel __unused)
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{
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#ifdef dbg
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dbg("reloc_jmpslot: *%p = %p", where, (void *)target);
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#endif
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if (!ld_bind_not)
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*where = target;
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return (target);
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}
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int
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reloc_iresolve(Obj_Entry *obj, RtldLockState *lockstate)
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{
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const Elf_Rela *relalim;
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const Elf_Rela *rela;
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if (!obj->irelative)
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return (0);
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relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize);
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for (rela = obj->pltrela; rela < relalim; rela++) {
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Elf_Addr *where, target, *ptr;
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switch (ELF_R_TYPE(rela->r_info)) {
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case R_X86_64_JMP_SLOT:
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break;
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case R_X86_64_IRELATIVE:
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ptr = (Elf_Addr *)(obj->relocbase + rela->r_addend);
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where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
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lock_release(rtld_bind_lock, lockstate);
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target = call_ifunc_resolver(ptr);
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wlock_acquire(rtld_bind_lock, lockstate);
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*where = target;
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break;
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}
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}
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obj->irelative = false;
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return (0);
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}
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int
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reloc_gnu_ifunc(Obj_Entry *obj, int flags, RtldLockState *lockstate)
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{
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const Elf_Rela *relalim;
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const Elf_Rela *rela;
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if (!obj->gnu_ifunc)
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return (0);
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relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize);
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for (rela = obj->pltrela; rela < relalim; rela++) {
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Elf_Addr *where, target;
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const Elf_Sym *def;
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const Obj_Entry *defobj;
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switch (ELF_R_TYPE(rela->r_info)) {
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case R_X86_64_JMP_SLOT:
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where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
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def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
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SYMLOOK_IN_PLT | flags, NULL, lockstate);
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if (def == NULL)
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return (-1);
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if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC)
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continue;
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lock_release(rtld_bind_lock, lockstate);
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target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
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wlock_acquire(rtld_bind_lock, lockstate);
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reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela);
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break;
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}
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}
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obj->gnu_ifunc = false;
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return (0);
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}
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uint32_t cpu_feature, cpu_feature2, cpu_stdext_feature, cpu_stdext_feature2;
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void
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ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused)
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{
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u_int p[4], cpu_high;
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do_cpuid(1, p);
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cpu_feature = p[3];
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cpu_feature2 = p[2];
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do_cpuid(0, p);
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cpu_high = p[0];
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if (cpu_high >= 7) {
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cpuid_count(7, 0, p);
|
|
cpu_stdext_feature = p[1];
|
|
cpu_stdext_feature2 = p[2];
|
|
}
|
|
}
|
|
|
|
void
|
|
pre_init(void)
|
|
{
|
|
|
|
}
|
|
|
|
int __getosreldate(void);
|
|
|
|
void
|
|
allocate_initial_tls(Obj_Entry *objs)
|
|
{
|
|
void *addr;
|
|
|
|
/*
|
|
* Fix the size of the static TLS block by using the maximum
|
|
* offset allocated so far and adding a bit for dynamic
|
|
* modules to use.
|
|
*/
|
|
tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
|
|
|
|
addr = allocate_tls(objs, 0, 3 * sizeof(Elf_Addr), sizeof(Elf_Addr));
|
|
if (__getosreldate() >= P_OSREL_WRFSBASE &&
|
|
(cpu_stdext_feature & CPUID_STDEXT_FSGSBASE) != 0)
|
|
wrfsbase((uintptr_t)addr);
|
|
else
|
|
sysarch(AMD64_SET_FSBASE, &addr);
|
|
}
|
|
|
|
void *__tls_get_addr(tls_index *ti)
|
|
{
|
|
Elf_Addr** segbase;
|
|
|
|
__asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
|
|
|
|
return tls_get_addr_common(&segbase[1], ti->ti_module, ti->ti_offset);
|
|
}
|