arch/arm/mdreloc.c

#include <sys/types.h>
#include <sys/stat.h>

#include "debug.h"
#include "rtld.h"

void
_rtld_setup_pltgot(const Obj_Entry *obj)
{
	obj->pltgot[1] = (Elf_Addr) obj;
	obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
}

int
_rtld_relocate_nonplt_objects(obj, self, dodebug)
	const Obj_Entry *obj;
	bool self;
	bool dodebug;
{
	const Elf_Rel *rel;

	for (rel = obj->rel; rel < obj->rellim; rel++) {
		Elf_Addr        *where;
		const Elf_Sym   *def;
		const Obj_Entry *defobj;
		Elf_Addr         tmp;
		unsigned long	 symnum;

		where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
		symnum = ELF_R_SYM(rel->r_info);

		switch (ELF_R_TYPE(rel->r_info)) {
		case R_TYPE(NONE):
			break;

#if 1 /* XXX should not occur */
		case R_TYPE(PC24): {	/* word32 S - P + A */
			Elf32_Sword addend;

			/*
			 * Extract addend and sign-extend if needed.
			 */
			addend = *where;
			if (addend & 0x00800000)
				addend |= 0xff000000;

			def = _rtld_find_symdef(symnum, obj, &defobj, false);
			if (def == NULL)
				return -1;
			tmp = (Elf_Addr)obj->relocbase + def->st_value
			    - (Elf_Addr)where + (addend << 2);
			if ((tmp & 0xfe000000) != 0xfe000000 &&
			    (tmp & 0xfe000000) != 0) {
				_rtld_error(
				"%s: R_ARM_PC24 relocation @ %p to %s failed "
				"(displacement %ld (%#lx) out of range)",
				    obj->path, where,
				    obj->strtab + obj->symtab[symnum].st_name,
				    (long) tmp, (long) tmp);
				return -1;
			}
			tmp >>= 2;
			*where = (*where & 0xff000000) | (tmp & 0x00ffffff);
			rdbg(dodebug, ("PC24 %s in %s --> %p @ %p in %s",
			    obj->strtab + obj->symtab[symnum].st_name,
			    obj->path, (void *)*where, where, defobj->path));
			break;
		}
#endif

		case R_TYPE(ABS32):	/* word32 B + S + A */
			def = _rtld_find_symdef(symnum, obj, &defobj, false);
			if (def == NULL)
				return -1;
			*where += (Elf_Addr)defobj->relocbase + def->st_value;
			rdbg(dodebug, ("ABS32 %s in %s --> %p @ %p in %s",
			    obj->strtab + obj->symtab[symnum].st_name,
			    obj->path, (void *)*where, where, defobj->path));
			break;

		case R_TYPE(GLOB_DAT):	/* word32 B + S */
			def = _rtld_find_symdef(symnum, obj, &defobj, false);
			if (def == NULL)
				return -1;
			*where = (Elf_Addr)(defobj->relocbase + def->st_value);
			rdbg(dodebug, ("GLOB_DAT %s in %s --> %p @ %p in %s",
			    obj->strtab + obj->symtab[symnum].st_name,
			    obj->path, (void *)*where, where, defobj->path));
			break;

		case R_TYPE(RELATIVE):	/* word32 B + A */
		    {
			extern Elf_Addr	_GLOBAL_OFFSET_TABLE_[];
			extern Elf_Addr	_GOT_END_[];

			/* This is the ...iffy hueristic. */
			if (!self ||
			    (caddr_t)where < (caddr_t)_GLOBAL_OFFSET_TABLE_ ||
			    (caddr_t)where >= (caddr_t)_GOT_END_) {
				*where += (Elf_Addr)obj->relocbase;
				rdbg(dodebug, ("RELATIVE in %s --> %p",
				    obj->path, (void *)*where));
			} else
				rdbg(dodebug, ("RELATIVE in %s stays at %p",
				    obj->path, (void *)*where));
			break;
		    }

		case R_TYPE(COPY):
			/*
			 * These are deferred until all other relocations have
			 * been done.  All we do here is make sure that the
			 * COPY relocation is not in a shared library.  They
			 * are allowed only in executable files.
			 */
			if (obj->isdynamic) {
				_rtld_error(
			"%s: Unexpected R_COPY relocation in shared library",
				    obj->path);
				return -1;
			}
			rdbg(dodebug, ("COPY (avoid in main)"));
			break;

		default:
			rdbg(dodebug, ("sym = %lu, type = %lu, offset = %p, "
			    "contents = %p, symbol = %s",
			    symnum, (u_long)ELF_R_TYPE(rel->r_info),
			    (void *)rel->r_offset, (void *)*where,
			    obj->strtab + obj->symtab[symnum].st_name));
			_rtld_error("%s: Unsupported relocation type %ld "
			    "in non-PLT relocations\n",
			    obj->path, (u_long) ELF_R_TYPE(rel->r_info));
			return -1;
		}
	}
	return 0;
}

int
_rtld_relocate_plt_lazy(obj, dodebug)
	const Obj_Entry *obj;
	bool dodebug;
{
	const Elf_Rel *rel;

	if (!obj->isdynamic)
		return 0;

	for (rel = obj->pltrel; rel < obj->pltrellim; rel++) {
		Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset);

		assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JUMP_SLOT));

		/* Just relocate the GOT slots pointing into the PLT */
		*where += (Elf_Addr)obj->relocbase;
		rdbg(dodebug, ("fixup !main in %s --> %p", obj->path,
		    (void *)*where));
	}

	return 0;
}

int
_rtld_relocate_plt_object(obj, rela, addrp, dodebug)
	const Obj_Entry *obj;
	const Elf_Rela *rela;
	caddr_t *addrp;
	bool dodebug;
{
	Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
	Elf_Addr new_value;
	const Elf_Sym  *def;
	const Obj_Entry *defobj;

	assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT));

	def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true);
	if (def == NULL)
		return -1;

	new_value = (Elf_Addr)(defobj->relocbase + def->st_value);
	rdbg(dodebug, ("bind now/fixup in %s --> old=%p new=%p",
	    defobj->strtab + def->st_name, (void *)*where, (void *)new_value));
	if (*where != new_value)
		*where = new_value;

	*addrp = (caddr_t)new_value;
	return 0;
}