1 /* Transformation functions for ELF data types.
2    Copyright (C) 1998,1999,2000,2002,2004,2005,2006,2007 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   memmove (dest, src, n);
56 }
57 
58 
59 /* We'll optimize the definition of the conversion functions here a
60    bit.  We need only functions for 16, 32, and 64 bits.  The
61    functions referenced in the table will be aliases for one of these
62    functions.  Which one is decided by the ELFxx_FSZ_type.  */
63 
64 #if ALLOW_UNALIGNED
65 
66 #define FETCH(Bits, ptr)	(*(const uint##Bits##_t *) ptr)
67 #define STORE(Bits, ptr, val)	(*(uint##Bits##_t *) ptr = val)
68 
69 #else
70 
71 union unaligned
72   {
73     uint16_t u16;
74     uint32_t u32;
75     uint64_t u64;
76   } __attribute__ ((packed));
77 
78 #define FETCH(Bits, ptr)	(((const union unaligned *) ptr)->u##Bits)
79 #define STORE(Bits, ptr, val)	(((union unaligned *) ptr)->u##Bits = val)
80 
81 #endif
82 
83 /* Now define the conversion functions for the basic types.  We use here
84    the fact that file and memory types are the same and that we have the
85    ELFxx_FSZ_* macros.
86 
87    At the same time we define inline functions which we will use to
88    convert the complex types.  */
89 #define FUNDAMENTAL(NAME, Name, Bits) \
90   INLINE2 (ELFW2(Bits,FSZ_##NAME), ElfW2(Bits,cvt_##Name), ElfW2(Bits,Name))
91 #define INLINE2(Bytes, FName, TName) \
92   INLINE3 (Bytes, FName, TName)
93 #define INLINE3(Bytes, FName, TName)					      \
94   static inline void FName##1 (void *dest, const void *ptr)		      \
95   {									      \
96     switch (Bytes)							      \
97       {									      \
98       case 2: STORE (16, dest, bswap_16 (FETCH (16, ptr))); break;	      \
99       case 4: STORE (32, dest, bswap_32 (FETCH (32, ptr))); break;	      \
100       case 8: STORE (64, dest, bswap_64 (FETCH (64, ptr))); break;	      \
101       default:								      \
102 	abort ();							      \
103       }									      \
104   }									      \
105 									      \
106   static void FName (void *dest, const void *ptr, size_t len,		      \
107 		     int encode __attribute__ ((unused)))		      \
108   {									      \
109     size_t n = len / sizeof (TName);					      \
110     if (dest < ptr)							      \
111       while (n-- > 0)							      \
112 	{								      \
113 	  FName##1 (dest, ptr);						      \
114 	  dest += Bytes;						      \
115 	  ptr += Bytes;							      \
116 	}								      \
117     else								      \
118       {									      \
119 	dest += len;							      \
120 	ptr += len;							      \
121 	while (n-- > 0)							      \
122 	  {								      \
123 	    ptr -= Bytes;						      \
124 	    dest -= Bytes;						      \
125 	    FName##1 (dest, ptr);					      \
126 	  }								      \
127       }									      \
128   }
129 
130 
131 /* Now the tricky part: define the transformation functions for the
132    complex types.  We will use the definitions of the types in
133    abstract.h.  */
134 #define START(Bits, Name, EName) \
135   static void								      \
136   ElfW2 (Bits, cvt_##Name) (void *dest, const void *src, size_t len,	      \
137 			    int encode __attribute__ ((unused)))	      \
138   { ElfW2(Bits, Name) *tdest = (ElfW2(Bits, Name) *) dest;		      \
139     ElfW2(Bits, Name) *tsrc = (ElfW2(Bits, Name) *) src;		      \
140     size_t n;								      \
141     for (n = len / sizeof (ElfW2(Bits, Name)); n > 0; ++tdest, ++tsrc, --n) {
142 #define END(Bits, Name) } }
143 #define TYPE_EXTRA(Code)
144 #define TYPE_XLATE(Code) Code
145 #define TYPE_NAME(Type, Name) TYPE_NAME2 (Type, Name)
146 #define TYPE_NAME2(Type, Name) Type##1 (&tdest->Name, &tsrc->Name);
147 #define TYPE(Name, Bits) TYPE2 (Name, Bits)
148 #define TYPE2(Name, Bits) TYPE3 (Name##Bits)
149 #define TYPE3(Name) Name (cvt_)
150 
151 /* Signal that we are generating conversion functions.  */
152 #define GENERATE_CONVERSION
153 
154 /* First generate the 32-bit conversion functions.  */
155 #define LIBELFBITS 32
156 #include "gelf_xlate.h"
157 
158 /* Now generate the 64-bit conversion functions.  */
159 #define LIBELFBITS 64
160 #include "gelf_xlate.h"
161 
162 
163 /* We have a few functions which we must create by hand since the sections
164    do not contain records of only one type.  */
165 #include "version_xlate.h"
166 #include "gnuhash_xlate.h"
167 #include "note_xlate.h"
168 
169 
170 /* Now the externally visible table with the function pointers.  */
171 const xfct_t __elf_xfctstom[EV_NUM - 1][EV_NUM - 1][ELFCLASSNUM - 1][ELF_T_NUM] =
172 {
173   [EV_CURRENT - 1] = {
174     [EV_CURRENT - 1] = {
175       [ELFCLASS32 - 1] = {
176 #define define_xfcts(Bits) \
177 	[ELF_T_BYTE]	= elf_cvt_Byte,					      \
178 	[ELF_T_ADDR]	= ElfW2(Bits, cvt_Addr),			      \
179 	[ELF_T_DYN]	= ElfW2(Bits, cvt_Dyn),				      \
180 	[ELF_T_EHDR]	= ElfW2(Bits, cvt_Ehdr),			      \
181 	[ELF_T_HALF]	= ElfW2(Bits, cvt_Half),			      \
182 	[ELF_T_OFF]	= ElfW2(Bits, cvt_Off),				      \
183 	[ELF_T_PHDR]	= ElfW2(Bits, cvt_Phdr),			      \
184 	[ELF_T_RELA]	= ElfW2(Bits, cvt_Rela),			      \
185 	[ELF_T_REL]	= ElfW2(Bits, cvt_Rel),				      \
186 	[ELF_T_SHDR]	= ElfW2(Bits, cvt_Shdr),			      \
187 	[ELF_T_SWORD]	= ElfW2(Bits, cvt_Sword),			      \
188 	[ELF_T_SYM]	= ElfW2(Bits, cvt_Sym),				      \
189 	[ELF_T_WORD]	= ElfW2(Bits, cvt_Word),			      \
190 	[ELF_T_XWORD]	= ElfW2(Bits, cvt_Xword),			      \
191 	[ELF_T_SXWORD]	= ElfW2(Bits, cvt_Sxword),			      \
192 	[ELF_T_VDEF]	= elf_cvt_Verdef,				      \
193 	[ELF_T_VDAUX]	= elf_cvt_Verdef,				      \
194 	[ELF_T_VNEED]	= elf_cvt_Verneed,				      \
195 	[ELF_T_VNAUX]	= elf_cvt_Verneed,				      \
196 	[ELF_T_NHDR]	= elf_cvt_note,					      \
197 	[ELF_T_SYMINFO] = ElfW2(Bits, cvt_Syminfo),			      \
198 	[ELF_T_MOVE]	= ElfW2(Bits, cvt_Move),			      \
199 	[ELF_T_LIB]	= ElfW2(Bits, cvt_Lib),				      \
200 	[ELF_T_AUXV]	= ElfW2(Bits, cvt_auxv_t)
201         define_xfcts (32),
202 	[ELF_T_GNUHASH] = Elf32_cvt_Word
203       },
204       [ELFCLASS64 - 1] = {
205 	define_xfcts (64),
206 	[ELF_T_GNUHASH] = elf_cvt_gnuhash
207       }
208     }
209   }
210 };
211 /* For now we only handle the case where the memory representation is the
212    same as the file representation.  Should this change we have to define
213    separate functions.  For now reuse them.  */
214 strong_alias (__elf_xfctstom, __elf_xfctstof)
215