xref: /titanic_51/usr/src/cmd/sgs/librtld/amd64/_relocate.c (revision 13faa91230bde46da937bf33010b9accc5bdeb59)
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 
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 */
41 void
42 undo_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 */
86 void
87 inc_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  */
101 void
102 clear_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  */
115 void
116 apply_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_rtld(type, oaddr, &value, reloc->r_name, name,
141 		    LIST(lmp));
142 	}
143 }
144