mdreloc.c revision 1.15 
1/*	$NetBSD: mdreloc.c,v 1.15 2002/09/26 20:42:11 mycroft Exp $	*/
2
3#include <sys/types.h>
4#include <sys/stat.h>
5
6#include "debug.h"
7#include "rtld.h"
8
9void _rtld_bind_start(void);
10void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
11caddr_t _rtld_bind __P((const Obj_Entry *, Elf_Word));
12
13void
14_rtld_setup_pltgot(const Obj_Entry *obj)
15{
16	obj->pltgot[1] = (Elf_Addr) obj;
17	obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
18}
19
20void
21_rtld_relocate_nonplt_self(dynp, relocbase)
22	Elf_Dyn *dynp;
23	Elf_Addr relocbase;
24{
25	const Elf_Rela *rela = 0, *relalim;
26	Elf_Addr relasz = 0;
27	Elf_Addr *where;
28
29	for (; dynp->d_tag != DT_NULL; dynp++) {
30		switch (dynp->d_tag) {
31		case DT_RELA:
32			rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr);
33			break;
34		case DT_RELASZ:
35			relasz = dynp->d_un.d_val;
36			break;
37		}
38	}
39	relalim = (const Elf_Rela *)((caddr_t)rela + relasz);
40	for (; rela < relalim; rela++) {
41		where = (Elf_Addr *)(relocbase + rela->r_offset);
42		*where += (Elf_Addr)relocbase;
43	}
44}
45
46int
47_rtld_relocate_nonplt_objects(obj)
48	const Obj_Entry *obj;
49{
50	const Elf_Rela *rela;
51
52	for (rela = obj->rela; rela < obj->relalim; rela++) {
53		Elf_Addr        *where;
54		const Elf_Sym   *def;
55		const Obj_Entry *defobj;
56		Elf_Addr         tmp;
57		unsigned long	 symnum;
58
59		where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
60		symnum = ELF_R_SYM(rela->r_info);
61
62		switch (ELF_R_TYPE(rela->r_info)) {
63		case R_TYPE(NONE):
64			break;
65
66#if 1 /* XXX should not occur */
67		case R_TYPE(PC32):
68			def = _rtld_find_symdef(symnum, obj, &defobj, false);
69			if (def == NULL)
70				return -1;
71
72			tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
73			    rela->r_addend) - (Elf_Addr)where;
74			if (*where != tmp)
75				*where = tmp;
76			rdbg(("PC32 %s in %s --> %p in %s",
77			    obj->strtab + obj->symtab[symnum].st_name,
78			    obj->path, (void *)*where, defobj->path));
79			break;
80
81		case R_TYPE(GOT32):
82#endif
83		case R_TYPE(32):
84		case R_TYPE(GLOB_DAT):
85			def = _rtld_find_symdef(symnum, obj, &defobj, false);
86			if (def == NULL)
87				return -1;
88
89			tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
90			    rela->r_addend);
91			if (*where != tmp)
92				*where = tmp;
93			rdbg(("32/GLOB_DAT %s in %s --> %p in %s",
94			    obj->strtab + obj->symtab[symnum].st_name,
95			    obj->path, (void *)*where, defobj->path));
96			break;
97
98		case R_TYPE(RELATIVE):
99			*where += (Elf_Addr)obj->relocbase;
100			rdbg(("RELATIVE in %s --> %p", obj->path,
101			    (void *)*where));
102			break;
103
104		case R_TYPE(COPY):
105			/*
106			 * These are deferred until all other relocations have
107			 * been done.  All we do here is make sure that the
108			 * COPY relocation is not in a shared library.  They
109			 * are allowed only in executable files.
110			 */
111			if (obj->isdynamic) {
112				_rtld_error(
113			"%s: Unexpected R_COPY relocation in shared library",
114				    obj->path);
115				return -1;
116			}
117			rdbg(("COPY (avoid in main)"));
118			break;
119
120		default:
121			rdbg(("sym = %lu, type = %lu, offset = %p, "
122			    "addend = %p, contents = %p, symbol = %s",
123			    symnum, (u_long)ELF_R_TYPE(rela->r_info),
124			    (void *)rela->r_offset, (void *)rela->r_addend,
125			    (void *)*where,
126			    obj->strtab + obj->symtab[symnum].st_name));
127			_rtld_error("%s: Unsupported relocation type %ld "
128			    "in non-PLT relocations\n",
129			    obj->path, (u_long) ELF_R_TYPE(rela->r_info));
130			return -1;
131		}
132	}
133	return 0;
134}
135
136int
137_rtld_relocate_plt_lazy(obj)
138	const Obj_Entry *obj;
139{
140	const Elf_Rela *rela;
141
142	if (!obj->isdynamic)
143		return 0;
144
145	for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) {
146		Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
147
148		assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
149
150		/* Just relocate the GOT slots pointing into the PLT */
151		*where += (Elf_Addr)obj->relocbase;
152		rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where));
153	}
154
155	return 0;
156}
157
158caddr_t
159_rtld_bind(obj, reloff)
160	const Obj_Entry *obj;
161	Elf_Word reloff;
162{
163	const Elf_Rela *rela = (const Elf_Rela *)((caddr_t)obj->pltrela + reloff);
164	Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
165	Elf_Addr new_value;
166	const Elf_Sym  *def;
167	const Obj_Entry *defobj;
168
169	assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
170
171	def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true);
172	if (def == NULL)
173		_rtld_die();
174
175	new_value = (Elf_Addr)(defobj->relocbase + def->st_value);
176	rdbg(("bind now/fixup in %s --> old=%p new=%p",
177	    defobj->strtab + def->st_name, (void *)*where, (void *)new_value));
178	if (*where != new_value)
179		*where = new_value;
180
181	return (caddr_t)new_value;
182}
183