xref: /titanic_44/usr/src/cmd/sgs/librtld/i386/_relocate.c (revision c28749e97052f09388969427adf7df641cdcdc22)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  *	Copyright (c) 2000-2001 by Sun Microsystems, Inc.
24  *	All rights reserved.
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 /*
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 void
41 undo_reloc(void *vrel, unsigned char *oaddr, unsigned char *iaddr,
42     Reloc *reloc)
43 {
44 	Rel		*rel = vrel;
45 	/* LINTED */
46 	unsigned long	*_oaddr = (unsigned long *)oaddr;
47 	/* LINTED */
48 	unsigned long	*_iaddr = (unsigned long *)iaddr;
49 
50 	switch (ELF_R_TYPE(rel->r_info)) {
51 	case R_386_NONE:
52 		break;
53 
54 	case R_386_COPY:
55 		(void) memset((void *)oaddr, 0, (size_t)reloc->r_size);
56 		break;
57 
58 	case R_386_JMP_SLOT:
59 		if (_iaddr)
60 			*_oaddr = *_iaddr + reloc->r_value;
61 		else
62 			*_oaddr = reloc->r_value;
63 		break;
64 
65 	default:
66 		if (_iaddr)
67 			*_oaddr = *_iaddr;
68 		else
69 			*_oaddr = 0;
70 		break;
71 	}
72 }
73 
74 
75 /*
76  * Copy a relocation record and increment its value.  The record must reflect
77  * the new address to which this image is fixed.  Note that .got entries
78  * associated with .plt's must be fixed to the new base address.
79  */
80 void
81 inc_reloc(void *vnrel, void *vorel, Reloc *reloc, unsigned char *oaddr,
82     unsigned char *iaddr)
83 {
84 	Rel		*nrel = vnrel;
85 	Rel		*orel = vorel;
86 	/* LINTED */
87 	unsigned long	*_oaddr = (unsigned long *)oaddr;
88 	/* LINTED */
89 	unsigned long	*_iaddr = (unsigned long *)iaddr;
90 
91 	if (ELF_R_TYPE(nrel->r_info) == R_386_JMP_SLOT) {
92 		if (_iaddr)
93 			*_oaddr = *_iaddr + reloc->r_value;
94 		else
95 			*_oaddr = reloc->r_value;
96 	}
97 
98 	*nrel = *orel;
99 	nrel->r_offset += reloc->r_value;
100 }
101 
102 
103 /*
104  * Clear a relocation record.  The relocation has been applied to the image and
105  * thus the relocation must not occur again.
106  */
107 void
108 clear_reloc(void * vrel)
109 {
110 	Rel *	rel = vrel;
111 
112 	rel->r_offset = 0;
113 	rel->r_info = ELF_R_INFO(0, R_386_NONE);
114 }
115 
116 
117 /*
118  * Apply a relocation to an image being built from an input file.  Use the
119  * runtime linkers routines to do the necessary magic.
120  */
121 void
122 apply_reloc(void *vrel, Reloc *reloc, const char *name,
123     unsigned char *oaddr, Rt_map *lmp)
124 {
125 	Rel	*rel = vrel;
126 	Byte	type = ELF_R_TYPE(rel->r_info);
127 	Word	value = reloc->r_value;
128 
129 	if (type == R_386_JMP_SLOT) {
130 		uintptr_t	addr, vaddr;
131 
132 		if (FLAGS(lmp) & FLG_RT_FIXED)
133 			vaddr = 0;
134 		else
135 			vaddr = ADDR(lmp);
136 		addr = (uintptr_t)oaddr - rel->r_offset;
137 		/* LINTED */
138 		elf_plt_write((uintptr_t)addr, vaddr, rel,
139 		    (uintptr_t)value, reloc->r_pltndx);
140 	} else if (type == R_386_COPY) {
141 		(void) memcpy((void *)oaddr, (void *)value,
142 		    (size_t)reloc->r_size);
143 
144 	} else {
145 		(void) do_reloc(type, oaddr, &value, reloc->r_name, name);
146 	}
147 }
148