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mdreloc.c revision 1.13 
      1 /*	$NetBSD: mdreloc.c,v 1.13 2002/09/25 07:27:55 mycroft Exp $	*/
      2 
      3 #include <sys/types.h>
      4 #include <sys/stat.h>
      5 
      6 #include "debug.h"
      7 #include "rtld.h"
      8 
      9 void _rtld_bind_start(void);
     10 caddr_t _rtld_bind __P((const Obj_Entry *, Elf_Word));
     11 
     12 void
     13 _rtld_setup_pltgot(const Obj_Entry *obj)
     14 {
     15 	obj->pltgot[1] = (Elf_Addr) obj;
     16 	obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
     17 }
     18 
     19 int
     20 _rtld_relocate_nonplt_objects(obj, self)
     21 	const Obj_Entry *obj;
     22 	bool self;
     23 {
     24 	const Elf_Rela *rela;
     25 
     26 	for (rela = obj->rela; rela < obj->relalim; rela++) {
     27 		Elf_Addr        *where;
     28 		const Elf_Sym   *def;
     29 		const Obj_Entry *defobj;
     30 		Elf_Addr         tmp;
     31 		unsigned long	 symnum;
     32 
     33 		where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
     34 		symnum = ELF_R_SYM(rela->r_info);
     35 
     36 		switch (ELF_R_TYPE(rela->r_info)) {
     37 		case R_TYPE(NONE):
     38 			break;
     39 
     40 		case R_TYPE(32):	/* word32 S + A */
     41 		case R_TYPE(GLOB_DAT):	/* word32 S + A */
     42 			def = _rtld_find_symdef(symnum, obj, &defobj, false);
     43 			if (def == NULL)
     44 				return -1;
     45 
     46 			tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
     47 			    rela->r_addend);
     48 
     49 			if (*where != tmp)
     50 				*where = tmp;
     51 			rdbg(("32/GLOB_DAT %s in %s --> %p in %s",
     52 			    obj->strtab + obj->symtab[symnum].st_name,
     53 			    obj->path, (void *)*where, defobj->path));
     54 			break;
     55 
     56 		case R_TYPE(RELATIVE):	/* word32 B + A */
     57 			tmp = (Elf_Addr)(obj->relocbase + rela->r_addend);
     58 			if (*where != tmp)
     59 				*where = tmp;
     60 			rdbg(("RELATIVE in %s --> %p", obj->path,
     61 			    (void *)*where));
     62 			break;
     63 
     64 		case R_TYPE(COPY):
     65 			/*
     66 			 * These are deferred until all other relocations have
     67 			 * been done.  All we do here is make sure that the
     68 			 * COPY relocation is not in a shared library.  They
     69 			 * are allowed only in executable files.
     70 			 */
     71 			if (obj->isdynamic) {
     72 				_rtld_error(
     73 			"%s: Unexpected R_COPY relocation in shared library",
     74 				    obj->path);
     75 				return -1;
     76 			}
     77 			rdbg(("COPY (avoid in main)"));
     78 			break;
     79 
     80 		default:
     81 			rdbg(("sym = %lu, type = %lu, offset = %p, "
     82 			    "addend = %p, contents = %p, symbol = %s",
     83 			    symnum, (u_long)ELF_R_TYPE(rela->r_info),
     84 			    (void *)rela->r_offset, (void *)rela->r_addend,
     85 			    (void *)*where,
     86 			    obj->strtab + obj->symtab[symnum].st_name));
     87 			_rtld_error("%s: Unsupported relocation type %ld "
     88 			    "in non-PLT relocations\n",
     89 			    obj->path, (u_long) ELF_R_TYPE(rela->r_info));
     90 			return -1;
     91 		}
     92 	}
     93 	return 0;
     94 }
     95 
     96 int
     97 _rtld_relocate_plt_lazy(obj)
     98 	const Obj_Entry *obj;
     99 {
    100 	const Elf_Rela *rela;
    101 
    102 	if (!obj->isdynamic)
    103 		return 0;
    104 
    105 	for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) {
    106 		Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
    107 
    108 		assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
    109 
    110 		/* Just relocate the GOT slots pointing into the PLT */
    111 		*where += (Elf_Addr)obj->relocbase;
    112 		rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where));
    113 	}
    114 
    115 	return 0;
    116 }
    117 
    118 caddr_t
    119 _rtld_bind(obj, reloff)
    120 	const Obj_Entry *obj;
    121 	Elf_Word reloff;
    122 {
    123 	const Elf_Rela *rela = (const Elf_Rela *)((caddr_t)obj->pltrela + reloff);
    124 	Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
    125 	Elf_Addr new_value;
    126 	const Elf_Sym  *def;
    127 	const Obj_Entry *defobj;
    128 
    129 	assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
    130 
    131 	def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true);
    132 	if (def == NULL)
    133 		_rtld_die();
    134 
    135 	new_value = (Elf_Addr)(defobj->relocbase + def->st_value +
    136 	    rela->r_addend);
    137 	rdbg(("bind now/fixup in %s --> old=%p new=%p",
    138 	    defobj->strtab + def->st_name, (void *)*where, (void *)new_value));
    139 	if (*where != new_value)
    140 		*where = new_value;
    141 
    142 	return (caddr_t)(new_value - rela->r_addend);
    143 }
    144