_relocate.c revision 5189:66a4f4f8a159 
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 2007 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26#pragma ident	"%Z%%M%	%I%	%E% SMI"
27
28#include	<string.h>
29#include	"machdep.h"
30#include	"reloc.h"
31#include	"_librtld.h"
32#include	"_elf.h"
33
34/*
35 * Undo relocations that have been applied to a memory image.  Basically this
36 * involves copying the original files relocation offset into the new image
37 * being created.
38 */
39void
40undo_reloc(void *vrel, uchar_t *oaddr, uchar_t *iaddr, Reloc *reloc)
41{
42	Rel	*rel = vrel;
43	/* LINTED */
44	ulong_t	*_oaddr = (ulong_t *)oaddr;
45	/* LINTED */
46	ulong_t	*_iaddr = (ulong_t *)iaddr;
47
48	switch (ELF_R_TYPE(rel->r_info)) {
49	case R_386_NONE:
50		break;
51
52	case R_386_COPY:
53		(void) memset((void *)oaddr, 0, (size_t)reloc->r_size);
54		break;
55
56	case R_386_JMP_SLOT:
57		if (_iaddr)
58			*_oaddr = *_iaddr + reloc->r_value;
59		else
60			*_oaddr = reloc->r_value;
61		break;
62
63	default:
64		if (_iaddr)
65			*_oaddr = *_iaddr;
66		else
67			*_oaddr = 0;
68		break;
69	}
70}
71
72/*
73 * Copy a relocation record and increment its value.  The record must reflect
74 * the new address to which this image is fixed.  Note that .got entries
75 * associated with .plt's must be fixed to the new base address.
76 */
77void
78inc_reloc(void *vnrel, void *vorel, Reloc *reloc, uchar_t *oaddr,
79    uchar_t *iaddr)
80{
81	Rel	*nrel = vnrel;
82	Rel	*orel = vorel;
83	/* LINTED */
84	ulong_t	*_oaddr = (ulong_t *)oaddr;
85	/* LINTED */
86	ulong_t	*_iaddr = (ulong_t *)iaddr;
87
88	if (ELF_R_TYPE(nrel->r_info) == R_386_JMP_SLOT) {
89		if (_iaddr)
90			*_oaddr = *_iaddr + reloc->r_value;
91		else
92			*_oaddr = reloc->r_value;
93	}
94
95	*nrel = *orel;
96	nrel->r_offset += reloc->r_value;
97}
98
99/*
100 * Clear a relocation record.  The relocation has been applied to the image and
101 * thus the relocation must not occur again.
102 */
103void
104clear_reloc(void *vrel)
105{
106	Rel	*rel = vrel;
107
108	rel->r_offset = 0;
109	rel->r_info = ELF_R_INFO(0, R_386_NONE);
110}
111
112/*
113 * Apply a relocation to an image being built from an input file.  Use the
114 * runtime linkers routines to do the necessary magic.
115 */
116void
117apply_reloc(void *vrel, Reloc *reloc, const char *name, uchar_t *oaddr,
118    Rt_map *lmp)
119{
120	Rel	*rel = vrel;
121	Xword	type = ELF_R_TYPE(rel->r_info);
122	Word	value = reloc->r_value;
123
124	if (type == R_386_JMP_SLOT) {
125		uintptr_t	addr, vaddr;
126
127		if (FLAGS(lmp) & FLG_RT_FIXED)
128			vaddr = 0;
129		else
130			vaddr = ADDR(lmp);
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_386_COPY) {
137		(void) memcpy((void *)oaddr, (void *)value,
138		    (size_t)reloc->r_size);
139	} else {
140		(void) do_reloc_rtld(type, oaddr, &value, reloc->r_name, name,
141		    LIST(lmp));
142	}
143}
144