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mdreloc.c revision 1.14 
      1 /*	$NetBSD: mdreloc.c,v 1.14 2002/09/26 20:42:12 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)
     21 	const Obj_Entry *obj;
     22 {
     23 	const Elf_Rela *rela;
     24 
     25 	for (rela = obj->rela; rela < obj->relalim; rela++) {
     26 		Elf_Addr        *where;
     27 		const Elf_Sym   *def;
     28 		const Obj_Entry *defobj;
     29 		Elf_Addr         tmp;
     30 		unsigned long	 symnum;
     31 
     32 		where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
     33 		symnum = ELF_R_SYM(rela->r_info);
     34 
     35 		switch (ELF_R_TYPE(rela->r_info)) {
     36 		case R_TYPE(NONE):
     37 			break;
     38 
     39 		case R_TYPE(32):	/* word32 S + A */
     40 		case R_TYPE(GLOB_DAT):	/* word32 S + A */
     41 			def = _rtld_find_symdef(symnum, obj, &defobj, false);
     42 			if (def == NULL)
     43 				return -1;
     44 
     45 			tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
     46 			    rela->r_addend);
     47 
     48 			if (*where != tmp)
     49 				*where = tmp;
     50 			rdbg(("32/GLOB_DAT %s in %s --> %p in %s",
     51 			    obj->strtab + obj->symtab[symnum].st_name,
     52 			    obj->path, (void *)*where, defobj->path));
     53 			break;
     54 
     55 		case R_TYPE(RELATIVE):	/* word32 B + A */
     56 			tmp = (Elf_Addr)(obj->relocbase + rela->r_addend);
     57 			if (*where != tmp)
     58 				*where = tmp;
     59 			rdbg(("RELATIVE in %s --> %p", obj->path,
     60 			    (void *)*where));
     61 			break;
     62 
     63 		case R_TYPE(COPY):
     64 			/*
     65 			 * These are deferred until all other relocations have
     66 			 * been done.  All we do here is make sure that the
     67 			 * COPY relocation is not in a shared library.  They
     68 			 * are allowed only in executable files.
     69 			 */
     70 			if (obj->isdynamic) {
     71 				_rtld_error(
     72 			"%s: Unexpected R_COPY relocation in shared library",
     73 				    obj->path);
     74 				return -1;
     75 			}
     76 			rdbg(("COPY (avoid in main)"));
     77 			break;
     78 
     79 		default:
     80 			rdbg(("sym = %lu, type = %lu, offset = %p, "
     81 			    "addend = %p, contents = %p, symbol = %s",
     82 			    symnum, (u_long)ELF_R_TYPE(rela->r_info),
     83 			    (void *)rela->r_offset, (void *)rela->r_addend,
     84 			    (void *)*where,
     85 			    obj->strtab + obj->symtab[symnum].st_name));
     86 			_rtld_error("%s: Unsupported relocation type %ld "
     87 			    "in non-PLT relocations\n",
     88 			    obj->path, (u_long) ELF_R_TYPE(rela->r_info));
     89 			return -1;
     90 		}
     91 	}
     92 	return 0;
     93 }
     94 
     95 int
     96 _rtld_relocate_plt_lazy(obj)
     97 	const Obj_Entry *obj;
     98 {
     99 	const Elf_Rela *rela;
    100 
    101 	if (!obj->isdynamic)
    102 		return 0;
    103 
    104 	for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) {
    105 		Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
    106 
    107 		assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
    108 
    109 		/* Just relocate the GOT slots pointing into the PLT */
    110 		*where += (Elf_Addr)obj->relocbase;
    111 		rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where));
    112 	}
    113 
    114 	return 0;
    115 }
    116 
    117 caddr_t
    118 _rtld_bind(obj, reloff)
    119 	const Obj_Entry *obj;
    120 	Elf_Word reloff;
    121 {
    122 	const Elf_Rela *rela = (const Elf_Rela *)((caddr_t)obj->pltrela + reloff);
    123 	Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
    124 	Elf_Addr new_value;
    125 	const Elf_Sym  *def;
    126 	const Obj_Entry *defobj;
    127 
    128 	assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
    129 
    130 	def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true);
    131 	if (def == NULL)
    132 		_rtld_die();
    133 
    134 	new_value = (Elf_Addr)(defobj->relocbase + def->st_value +
    135 	    rela->r_addend);
    136 	rdbg(("bind now/fixup in %s --> old=%p new=%p",
    137 	    defobj->strtab + def->st_name, (void *)*where, (void *)new_value));
    138 	if (*where != new_value)
    139 		*where = new_value;
    140 
    141 	return (caddr_t)(new_value - rela->r_addend);
    142 }
    143