. file- and functionality-compatible with previous situation (FreeBSD csu) (with a crt1.o -> crt0.o symlink in /usr/lib) . harmonizes source with netbsd . harmonizes linker invocation (e.g. clang) with netbsd . helpful to get some arm code in there for the arm port project
224 lines
5.4 KiB
C
224 lines
5.4 KiB
C
/* $NetBSD: mdreloc.c,v 1.27 2010/08/06 16:33:18 joerg Exp $ */
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#include <sys/cdefs.h>
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#ifndef lint
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__RCSID("$NetBSD: mdreloc.c,v 1.27 2010/08/06 16:33:18 joerg Exp $");
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#endif /* not lint */
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#include <sys/cdefs.h>
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#ifndef lint
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__RCSID("$NetBSD: mdreloc.c,v 1.27 2010/08/06 16:33:18 joerg Exp $");
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#endif /* not lint */
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#include <sys/types.h>
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#include "debug.h"
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#include "rtld.h"
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void _rtld_bind_start(void);
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void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
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caddr_t _rtld_bind(const Obj_Entry *, Elf_Word);
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static inline int _rtld_relocate_plt_object(const Obj_Entry *,
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const Elf_Rela *, Elf_Addr *);
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void
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_rtld_setup_pltgot(const Obj_Entry *obj)
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{
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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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void
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_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
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{
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const Elf_Rela *rela = 0, *relalim;
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Elf_Addr relasz = 0;
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Elf_Addr *where;
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for (; dynp->d_tag != DT_NULL; dynp++) {
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switch (dynp->d_tag) {
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case DT_RELA:
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rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr);
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break;
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case DT_RELASZ:
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relasz = dynp->d_un.d_val;
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break;
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}
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}
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relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz);
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for (; rela < relalim; rela++) {
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where = (Elf_Addr *)(relocbase + rela->r_offset);
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*where += (Elf_Addr)relocbase;
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}
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}
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int
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_rtld_relocate_nonplt_objects(Obj_Entry *obj)
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{
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const Elf_Rela *rela;
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for (rela = obj->rela; rela < obj->relalim; rela++) {
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Elf_Addr *where;
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const Elf_Sym *def;
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const Obj_Entry *defobj;
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Elf_Addr tmp;
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unsigned long symnum;
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where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
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symnum = ELF_R_SYM(rela->r_info);
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switch (ELF_R_TYPE(rela->r_info)) {
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case R_TYPE(NONE):
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break;
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#if 1 /* XXX should not occur */
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case R_TYPE(PC32):
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def = _rtld_find_symdef(symnum, obj, &defobj, false);
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if (def == NULL)
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return -1;
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tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
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rela->r_addend) - (Elf_Addr)where;
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if (*where != tmp)
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*where = tmp;
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rdbg(("PC32 %s in %s --> %p in %s",
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obj->strtab + obj->symtab[symnum].st_name,
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obj->path, (void *)*where, defobj->path));
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break;
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case R_TYPE(GOT32):
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#endif
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case R_TYPE(32):
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case R_TYPE(GLOB_DAT):
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def = _rtld_find_symdef(symnum, obj, &defobj, false);
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if (def == NULL)
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return -1;
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tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
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rela->r_addend);
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if (*where != tmp)
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*where = tmp;
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rdbg(("32/GLOB_DAT %s in %s --> %p in %s",
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obj->strtab + obj->symtab[symnum].st_name,
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obj->path, (void *)*where, defobj->path));
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break;
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case R_TYPE(RELATIVE):
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*where += (Elf_Addr)obj->relocbase;
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rdbg(("RELATIVE in %s --> %p", obj->path,
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(void *)*where));
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break;
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case R_TYPE(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
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* COPY relocation is not in a shared library. They
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* are allowed only in executable files.
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*/
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if (obj->isdynamic) {
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_rtld_error(
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"%s: Unexpected R_COPY relocation in shared library",
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obj->path);
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return -1;
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}
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rdbg(("COPY (avoid in main)"));
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break;
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default:
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rdbg(("sym = %lu, type = %lu, offset = %p, "
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"addend = %p, contents = %p, symbol = %s",
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symnum, (u_long)ELF_R_TYPE(rela->r_info),
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(void *)rela->r_offset, (void *)rela->r_addend,
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(void *)*where,
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obj->strtab + obj->symtab[symnum].st_name));
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_rtld_error("%s: Unsupported relocation type %ld "
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"in non-PLT relocations",
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obj->path, (u_long) 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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int
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_rtld_relocate_plt_lazy(const Obj_Entry *obj)
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{
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const Elf_Rela *rela;
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if (!obj->relocbase)
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return 0;
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for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) {
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Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
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assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
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/* Just relocate the GOT slots pointing into the PLT */
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*where += (Elf_Addr)obj->relocbase;
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rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where));
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}
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return 0;
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}
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static inline int
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_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela,
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Elf_Addr *tp)
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{
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Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
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Elf_Addr new_value;
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const Elf_Sym *def;
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const Obj_Entry *defobj;
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unsigned long info = rela->r_info;
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assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT));
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def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL);
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if (__predict_false(def == NULL))
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return -1;
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if (__predict_false(def == &_rtld_sym_zero))
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return 0;
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assert(rela->r_addend == 0);
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new_value = (Elf_Addr)(defobj->relocbase + def->st_value +
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rela->r_addend);
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rdbg(("bind now/fixup in %s --> old=%p new=%p",
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defobj->strtab + def->st_name, (void *)*where, (void *)new_value));
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if (*where != new_value)
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*where = new_value;
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if (tp)
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*tp = new_value - rela->r_addend;
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return 0;
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}
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caddr_t
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_rtld_bind(const Obj_Entry *obj, Elf_Word reloff)
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{
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const Elf_Rela *rela = (const Elf_Rela *)((const uint8_t *)obj->pltrela + reloff);
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Elf_Addr result;
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int err;
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result = 0; /* XXX gcc */
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err = _rtld_relocate_plt_object(obj, rela, &result);
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if (err)
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_rtld_die();
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return (caddr_t)result;
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}
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int
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_rtld_relocate_plt_objects(const Obj_Entry *obj)
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{
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const Elf_Rela *rela;
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for (rela = obj->pltrela; rela < obj->pltrelalim; rela++)
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if (_rtld_relocate_plt_object(obj, rela, NULL) < 0)
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return -1;
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return 0;
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}
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