_relocate.c revision 1618:8c9a4f31d225 
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29#include	<string.h>
30#include	"machdep.h"
31#include	"reloc.h"
32#include	"_librtld.h"
33#include	"_elf.h"
34
35/*
36 * Undo relocations that have been applied to a memory image.  Basically this
37 * involves copying the original files relocation offset into the new image
38 * being created.
39 */
40/* ARGSUSED3 */
41void
42undo_reloc(void *vrel, uchar_t *oaddr, uchar_t *iaddr, Reloc *reloc)
43{
44	Rela		*rel = vrel;
45	const Rel_entry	*rep;
46	Xword		rtype = ELF_R_TYPE(rel->r_info);
47	ulong_t		*_oaddr;
48	ulong_t		*_iaddr;
49
50	switch (rtype) {
51	case R_AMD64_NONE:
52		break;
53	case R_AMD64_COPY:
54		(void) memset((void *)oaddr, 0, (size_t)reloc->r_size);
55		break;
56	case R_AMD64_JUMP_SLOT:
57		/* LINTED */
58		_oaddr = (unsigned long *)oaddr;
59		/* LINTED */
60		_iaddr = (unsigned long *)iaddr;
61
62		if (_iaddr) {
63			*_oaddr++ = *_iaddr++;
64			*_oaddr++ = *_iaddr++;
65			*_oaddr = *_iaddr;
66		} else {
67			*_oaddr++ = 0;
68			*_oaddr++ = 0;
69			*_oaddr = 0;
70		}
71		break;
72	default:
73		rep = &reloc_table[rtype];
74		if (iaddr)
75			(void) memcpy(oaddr, iaddr, rep->re_fsize);
76		else
77			(void) memset(oaddr, 0, rep->re_fsize);
78	}
79}
80
81/*
82 * Copy a relocation record and increment its value.  The record must reflect
83 * the new address to which this image is fixed.
84 */
85/* ARGSUSED3 */
86void
87inc_reloc(void *vnrel, void *vorel, Reloc *reloc, uchar_t *oaddr,
88    uchar_t *iaddr)
89{
90	Rela	*nrel = vnrel;
91	Rela	*orel = vorel;
92
93	*nrel = *orel;
94	nrel->r_offset += reloc->r_value;
95}
96
97/*
98 * Clear a relocation record.  The relocation has been applied to the image and
99 * thus the relocation must not occur again.
100 */
101void
102clear_reloc(void *vrel)
103{
104	Rela	*rel = vrel;
105
106	rel->r_offset = 0;
107	rel->r_info = ELF_R_INFO(0, R_AMD64_NONE);
108	rel->r_addend = 0;
109}
110
111/*
112 * Apply a relocation to an image being built from an input file.  Use the
113 * runtime linkers routines to do the necessary magic.
114 */
115void
116apply_reloc(void *vrel, Reloc *reloc, const char *name, uchar_t *oaddr,
117    Rt_map *lmp)
118{
119	Rela	*rel = vrel;
120	Xword	type = ELF_R_TYPE(rel->r_info);
121	Xword	value = reloc->r_value + rel->r_addend;
122
123	if (type == R_AMD64_JUMP_SLOT) {
124		uintptr_t	addr, vaddr;
125
126		if (FLAGS(lmp) & FLG_RT_FIXED)
127			vaddr = 0;
128		else
129			vaddr = ADDR(lmp);
130
131		addr = (uintptr_t)oaddr - rel->r_offset;
132		/* LINTED */
133		elf_plt_write((uintptr_t)addr, vaddr, rel,
134		    (uintptr_t)value, reloc->r_pltndx);
135
136	} else if (type == R_AMD64_COPY) {
137		(void) memcpy((void *)oaddr, (void *)value,
138		    (size_t)reloc->r_size);
139	} else {
140		(void) do_reloc(type, oaddr, &value, reloc->r_name, name,
141		    LIST(lmp));
142	}
143}
144