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1 /* Transformation functions for ELF data types.
2    Copyright (C) 1998,1999,2000,2002,2004,2005,2006,2007,2015 Red Hat, Inc.
3    This file is part of elfutils.
4    Written by Ulrich Drepper <drepper@redhat.com>, 1998.
5 
6    This file is free software; you can redistribute it and/or modify
7    it under the terms of either
8 
9      * the GNU Lesser General Public License as published by the Free
10        Software Foundation; either version 3 of the License, or (at
11        your option) any later version
12 
13    or
14 
15      * the GNU General Public License as published by the Free
16        Software Foundation; either version 2 of the License, or (at
17        your option) any later version
18 
19    or both in parallel, as here.
20 
21    elfutils is distributed in the hope that it will be useful, but
22    WITHOUT ANY WARRANTY; without even the implied warranty of
23    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
24    General Public License for more details.
25 
26    You should have received copies of the GNU General Public License and
27    the GNU Lesser General Public License along with this program.  If
28    not, see <http://www.gnu.org/licenses/>.  */
29 
30 #ifdef HAVE_CONFIG_H
31 # include <config.h>
32 #endif
33 
34 #include <byteswap.h>
35 #include <stdint.h>
36 #include <string.h>
37 #include <stdlib.h>
38 
39 #include "libelfP.h"
40 
41 #ifndef LIBELFBITS
42 # define LIBELFBITS	32
43 #endif
44 
45 
46 /* Well, what shall I say.  Nothing to do here.  */
47 #define elf_cvt_Byte(dest, src, n) \
48   (__builtin_constant_p (n) && (n) == 1					      \
49    ? (void) (*((char *) (dest)) = *((char *) (src)))			      \
50    : Elf32_cvt_Byte (dest, src, n))
51 static void
52 (elf_cvt_Byte) (void *dest, const void *src, size_t n,
53 		int encode __attribute__ ((unused)))
54 {
55   if (n != 0)
56     memmove (dest, src, n);
57 }
58 
59 
60 /* We'll optimize the definition of the conversion functions here a
61    bit.  We need only functions for 16, 32, and 64 bits.  The
62    functions referenced in the table will be aliases for one of these
63    functions.  Which one is decided by the ELFxx_FSZ_type.  */
64 
65 #if ALLOW_UNALIGNED
66 
67 #define FETCH(Bits, ptr)	(*(const uint##Bits##_t *) ptr)
68 #define STORE(Bits, ptr, val)	(*(uint##Bits##_t *) ptr = val)
69 
70 #else
71 
72 union unaligned
73   {
74     uint16_t u16;
75     uint32_t u32;
76     uint64_t u64;
77   } __attribute__ ((packed));
78 
79 #define FETCH(Bits, ptr)	(((const union unaligned *) ptr)->u##Bits)
80 #define STORE(Bits, ptr, val)	(((union unaligned *) ptr)->u##Bits = val)
81 
82 #endif
83 
84 /* Now define the conversion functions for the basic types.  We use here
85    the fact that file and memory types are the same and that we have the
86    ELFxx_FSZ_* macros.
87 
88    At the same time we define inline functions which we will use to
89    convert the complex types.  */
90 #define FUNDAMENTAL(NAME, Name, Bits) \
91   INLINE2 (ELFW2(Bits,FSZ_##NAME), ElfW2(Bits,cvt_##Name), ElfW2(Bits,Name))
92 #define INLINE2(Bytes, FName, TName) \
93   INLINE3 (Bytes, FName, TName)
94 #define INLINE3(Bytes, FName, TName)					      \
95   static inline void FName##1 (void *dest, const void *ptr)		      \
96   {									      \
97     switch (Bytes)							      \
98       {									      \
99       case 2: STORE (16, dest, bswap_16 (FETCH (16, ptr))); break;	      \
100       case 4: STORE (32, dest, bswap_32 (FETCH (32, ptr))); break;	      \
101       case 8: STORE (64, dest, bswap_64 (FETCH (64, ptr))); break;	      \
102       default:								      \
103 	abort ();							      \
104       }									      \
105   }									      \
106 									      \
107   static void FName (void *dest, const void *ptr, size_t len,		      \
108 		     int encode __attribute__ ((unused)))		      \
109   {									      \
110     size_t n = len / sizeof (TName);					      \
111     if (dest < ptr)							      \
112       while (n-- > 0)							      \
113 	{								      \
114 	  FName##1 (dest, ptr);						      \
115 	  dest += Bytes;						      \
116 	  ptr += Bytes;							      \
117 	}								      \
118     else								      \
119       {									      \
120 	dest += len;							      \
121 	ptr += len;							      \
122 	while (n-- > 0)							      \
123 	  {								      \
124 	    ptr -= Bytes;						      \
125 	    dest -= Bytes;						      \
126 	    FName##1 (dest, ptr);					      \
127 	  }								      \
128       }									      \
129   }
130 
131 
132 /* Now the tricky part: define the transformation functions for the
133    complex types.  We will use the definitions of the types in
134    abstract.h.  */
135 #define START(Bits, Name, EName) \
136   static void								      \
137   ElfW2 (Bits, cvt_##Name) (void *dest, const void *src, size_t len,	      \
138 			    int encode __attribute__ ((unused)))	      \
139   { ElfW2(Bits, Name) *tdest = (ElfW2(Bits, Name) *) dest;		      \
140     ElfW2(Bits, Name) *tsrc = (ElfW2(Bits, Name) *) src;		      \
141     size_t n;								      \
142     for (n = len / sizeof (ElfW2(Bits, Name)); n > 0; ++tdest, ++tsrc, --n) {
143 #define END(Bits, Name) } }
144 #define TYPE_EXTRA(Code)
145 #define TYPE_XLATE(Code) Code
146 #define TYPE_NAME(Type, Name) TYPE_NAME2 (Type, Name)
147 #define TYPE_NAME2(Type, Name) Type##1 (&tdest->Name, &tsrc->Name);
148 #define TYPE(Name, Bits) TYPE2 (Name, Bits)
149 #define TYPE2(Name, Bits) TYPE3 (Name##Bits)
150 #define TYPE3(Name) Name (cvt_)
151 
152 /* Signal that we are generating conversion functions.  */
153 #define GENERATE_CONVERSION
154 
155 /* First generate the 32-bit conversion functions.  */
156 #define LIBELFBITS 32
157 #include "gelf_xlate.h"
158 
159 /* Now generate the 64-bit conversion functions.  */
160 #define LIBELFBITS 64
161 #include "gelf_xlate.h"
162 
163 
164 /* We have a few functions which we must create by hand since the sections
165    do not contain records of only one type.  */
166 #include "version_xlate.h"
167 #include "gnuhash_xlate.h"
168 #include "note_xlate.h"
169 #include "chdr_xlate.h"
170 
171 
172 /* Now the externally visible table with the function pointers.  */
173 const xfct_t __elf_xfctstom[EV_NUM - 1][EV_NUM - 1][ELFCLASSNUM - 1][ELF_T_NUM] =
174 {
175   [EV_CURRENT - 1] = {
176     [EV_CURRENT - 1] = {
177       [ELFCLASS32 - 1] = {
178 #define define_xfcts(Bits) \
179 	[ELF_T_BYTE]	= elf_cvt_Byte,					      \
180 	[ELF_T_ADDR]	= ElfW2(Bits, cvt_Addr),			      \
181 	[ELF_T_DYN]	= ElfW2(Bits, cvt_Dyn),				      \
182 	[ELF_T_EHDR]	= ElfW2(Bits, cvt_Ehdr),			      \
183 	[ELF_T_HALF]	= ElfW2(Bits, cvt_Half),			      \
184 	[ELF_T_OFF]	= ElfW2(Bits, cvt_Off),				      \
185 	[ELF_T_PHDR]	= ElfW2(Bits, cvt_Phdr),			      \
186 	[ELF_T_RELA]	= ElfW2(Bits, cvt_Rela),			      \
187 	[ELF_T_REL]	= ElfW2(Bits, cvt_Rel),				      \
188 	[ELF_T_SHDR]	= ElfW2(Bits, cvt_Shdr),			      \
189 	[ELF_T_SWORD]	= ElfW2(Bits, cvt_Sword),			      \
190 	[ELF_T_SYM]	= ElfW2(Bits, cvt_Sym),				      \
191 	[ELF_T_WORD]	= ElfW2(Bits, cvt_Word),			      \
192 	[ELF_T_XWORD]	= ElfW2(Bits, cvt_Xword),			      \
193 	[ELF_T_SXWORD]	= ElfW2(Bits, cvt_Sxword),			      \
194 	[ELF_T_VDEF]	= elf_cvt_Verdef,				      \
195 	[ELF_T_VDAUX]	= elf_cvt_Verdef,				      \
196 	[ELF_T_VNEED]	= elf_cvt_Verneed,				      \
197 	[ELF_T_VNAUX]	= elf_cvt_Verneed,				      \
198 	[ELF_T_NHDR]	= elf_cvt_note,					      \
199 	[ELF_T_SYMINFO] = ElfW2(Bits, cvt_Syminfo),			      \
200 	[ELF_T_MOVE]	= ElfW2(Bits, cvt_Move),			      \
201 	[ELF_T_LIB]	= ElfW2(Bits, cvt_Lib),				      \
202 	[ELF_T_AUXV]	= ElfW2(Bits, cvt_auxv_t),			      \
203 	[ELF_T_CHDR]	= ElfW2(Bits, cvt_chdr)
204         define_xfcts (32),
205 	[ELF_T_GNUHASH] = Elf32_cvt_Word
206       },
207       [ELFCLASS64 - 1] = {
208 	define_xfcts (64),
209 	[ELF_T_GNUHASH] = elf_cvt_gnuhash
210       }
211     }
212   }
213 };
214 /* For now we only handle the case where the memory representation is the
215    same as the file representation.  Should this change we have to define
216    separate functions.  For now reuse them.  */
217 strong_alias (__elf_xfctstom, __elf_xfctstof)
218