1 /* ELF support for BFD.
2    Copyright (C) 1991-2016 Free Software Foundation, Inc.
3 
4    Written by Fred Fish @ Cygnus Support, from information published
5    in "UNIX System V Release 4, Programmers Guide: ANSI C and
6    Programming Support Tools".
7 
8    This file is part of BFD, the Binary File Descriptor library.
9 
10    This program is free software; you can redistribute it and/or modify
11    it under the terms of the GNU General Public License as published by
12    the Free Software Foundation; either version 3 of the License, or
13    (at your option) any later version.
14 
15    This program is distributed in the hope that it will be useful,
16    but WITHOUT ANY WARRANTY; without even the implied warranty of
17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18    GNU General Public License for more details.
19 
20    You should have received a copy of the GNU General Public License
21    along with this program; if not, write to the Free Software
22    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
23    MA 02110-1301, USA.  */
24 
25 /* This file is part of ELF support for BFD, and contains the portions
26    that describe how ELF is represented externally by the BFD library.
27    I.E. it describes the in-file representation of ELF.  It requires
28    the elf/common.h file which contains the portions that are common to
29    both the internal and external representations.  */
30 
31 /* The 64-bit stuff is kind of random.  Perhaps someone will publish a
32    spec someday.  */
33 
34 #ifndef _ELF_EXTERNAL_H
35 #define _ELF_EXTERNAL_H
36 
37 /* Special section indices, which may show up in st_shndx fields, among
38    other places.  */
39 
40 #define SHN_LORESERVE	0xFF00		/* Begin range of reserved indices */
41 #define SHN_LOPROC	0xFF00		/* Begin range of appl-specific */
42 #define SHN_HIPROC	0xFF1F		/* End range of appl-specific */
43 #define SHN_LOOS	0xFF20		/* OS specific semantics, lo */
44 #define SHN_HIOS	0xFF3F		/* OS specific semantics, hi */
45 #define SHN_ABS		0xFFF1		/* Associated symbol is absolute */
46 #define SHN_COMMON	0xFFF2		/* Associated symbol is in common */
47 #define SHN_XINDEX	0xFFFF		/* Section index is held elsewhere */
48 #define SHN_HIRESERVE	0xFFFF		/* End range of reserved indices */
49 
50 /* ELF Header (32-bit implementations) */
51 
52 typedef struct {
53   unsigned char	e_ident[16];		/* ELF "magic number" */
54   unsigned char	e_type[2];		/* Identifies object file type */
55   unsigned char	e_machine[2];		/* Specifies required architecture */
56   unsigned char	e_version[4];		/* Identifies object file version */
57   unsigned char	e_entry[4];		/* Entry point virtual address */
58   unsigned char	e_phoff[4];		/* Program header table file offset */
59   unsigned char	e_shoff[4];		/* Section header table file offset */
60   unsigned char	e_flags[4];		/* Processor-specific flags */
61   unsigned char	e_ehsize[2];		/* ELF header size in bytes */
62   unsigned char	e_phentsize[2];		/* Program header table entry size */
63   unsigned char	e_phnum[2];		/* Program header table entry count */
64   unsigned char	e_shentsize[2];		/* Section header table entry size */
65   unsigned char	e_shnum[2];		/* Section header table entry count */
66   unsigned char	e_shstrndx[2];		/* Section header string table index */
67 } Elf32_External_Ehdr;
68 
69 typedef struct {
70   unsigned char	e_ident[16];		/* ELF "magic number" */
71   unsigned char	e_type[2];		/* Identifies object file type */
72   unsigned char	e_machine[2];		/* Specifies required architecture */
73   unsigned char	e_version[4];		/* Identifies object file version */
74   unsigned char	e_entry[8];		/* Entry point virtual address */
75   unsigned char	e_phoff[8];		/* Program header table file offset */
76   unsigned char	e_shoff[8];		/* Section header table file offset */
77   unsigned char	e_flags[4];		/* Processor-specific flags */
78   unsigned char	e_ehsize[2];		/* ELF header size in bytes */
79   unsigned char	e_phentsize[2];		/* Program header table entry size */
80   unsigned char	e_phnum[2];		/* Program header table entry count */
81   unsigned char	e_shentsize[2];		/* Section header table entry size */
82   unsigned char	e_shnum[2];		/* Section header table entry count */
83   unsigned char	e_shstrndx[2];		/* Section header string table index */
84 } Elf64_External_Ehdr;
85 
86 /* Program header */
87 
88 typedef struct {
89   unsigned char	p_type[4];		/* Identifies program segment type */
90   unsigned char	p_offset[4];		/* Segment file offset */
91   unsigned char	p_vaddr[4];		/* Segment virtual address */
92   unsigned char	p_paddr[4];		/* Segment physical address */
93   unsigned char	p_filesz[4];		/* Segment size in file */
94   unsigned char	p_memsz[4];		/* Segment size in memory */
95   unsigned char	p_flags[4];		/* Segment flags */
96   unsigned char	p_align[4];		/* Segment alignment, file & memory */
97 } Elf32_External_Phdr;
98 
99 typedef struct {
100   unsigned char	p_type[4];		/* Identifies program segment type */
101   unsigned char	p_flags[4];		/* Segment flags */
102   unsigned char	p_offset[8];		/* Segment file offset */
103   unsigned char	p_vaddr[8];		/* Segment virtual address */
104   unsigned char	p_paddr[8];		/* Segment physical address */
105   unsigned char	p_filesz[8];		/* Segment size in file */
106   unsigned char	p_memsz[8];		/* Segment size in memory */
107   unsigned char	p_align[8];		/* Segment alignment, file & memory */
108 } Elf64_External_Phdr;
109 
110 /* Section header */
111 
112 typedef struct {
113   unsigned char	sh_name[4];		/* Section name, index in string tbl */
114   unsigned char	sh_type[4];		/* Type of section */
115   unsigned char	sh_flags[4];		/* Miscellaneous section attributes */
116   unsigned char	sh_addr[4];		/* Section virtual addr at execution */
117   unsigned char	sh_offset[4];		/* Section file offset */
118   unsigned char	sh_size[4];		/* Size of section in bytes */
119   unsigned char	sh_link[4];		/* Index of another section */
120   unsigned char	sh_info[4];		/* Additional section information */
121   unsigned char	sh_addralign[4];	/* Section alignment */
122   unsigned char	sh_entsize[4];		/* Entry size if section holds table */
123 } Elf32_External_Shdr;
124 
125 typedef struct {
126   unsigned char	sh_name[4];		/* Section name, index in string tbl */
127   unsigned char	sh_type[4];		/* Type of section */
128   unsigned char	sh_flags[8];		/* Miscellaneous section attributes */
129   unsigned char	sh_addr[8];		/* Section virtual addr at execution */
130   unsigned char	sh_offset[8];		/* Section file offset */
131   unsigned char	sh_size[8];		/* Size of section in bytes */
132   unsigned char	sh_link[4];		/* Index of another section */
133   unsigned char	sh_info[4];		/* Additional section information */
134   unsigned char	sh_addralign[8];	/* Section alignment */
135   unsigned char	sh_entsize[8];		/* Entry size if section holds table */
136 } Elf64_External_Shdr;
137 
138 /* Compression header */
139 
140 typedef struct {
141   unsigned char	ch_type[4];		/* Type of compression */
142   unsigned char	ch_size[4];		/* Size of uncompressed data in bytes */
143   unsigned char	ch_addralign[4];	/* Alignment of uncompressed data  */
144 } Elf32_External_Chdr;
145 
146 typedef struct {
147   unsigned char	ch_type[4];		/* Type of compression */
148   unsigned char	ch_reserved[4];		/* Padding */
149   unsigned char	ch_size[8];		/* Size of uncompressed data in bytes */
150   unsigned char	ch_addralign[8];	/* Alignment of uncompressed data  */
151 } Elf64_External_Chdr;
152 
153 /* Symbol table entry */
154 
155 typedef struct {
156   unsigned char	st_name[4];		/* Symbol name, index in string tbl */
157   unsigned char	st_value[4];		/* Value of the symbol */
158   unsigned char	st_size[4];		/* Associated symbol size */
159   unsigned char	st_info[1];		/* Type and binding attributes */
160   unsigned char	st_other[1];		/* No defined meaning, 0 */
161   unsigned char	st_shndx[2];		/* Associated section index */
162 } Elf32_External_Sym;
163 
164 typedef struct {
165   unsigned char	st_name[4];		/* Symbol name, index in string tbl */
166   unsigned char	st_info[1];		/* Type and binding attributes */
167   unsigned char	st_other[1];		/* No defined meaning, 0 */
168   unsigned char	st_shndx[2];		/* Associated section index */
169   unsigned char	st_value[8];		/* Value of the symbol */
170   unsigned char	st_size[8];		/* Associated symbol size */
171 } Elf64_External_Sym;
172 
173 typedef struct {
174   unsigned char est_shndx[4];		/* Section index */
175 } Elf_External_Sym_Shndx;
176 
177 /* Note segments */
178 
179 typedef struct {
180   unsigned char	namesz[4];		/* Size of entry's owner string */
181   unsigned char	descsz[4];		/* Size of the note descriptor */
182   unsigned char	type[4];		/* Interpretation of the descriptor */
183   char		name[1];		/* Start of the name+desc data */
184 } Elf_External_Note;
185 
186 /* Relocation Entries */
187 typedef struct {
188   unsigned char r_offset[4];	/* Location at which to apply the action */
189   unsigned char	r_info[4];	/* index and type of relocation */
190 } Elf32_External_Rel;
191 
192 typedef struct {
193   unsigned char r_offset[4];	/* Location at which to apply the action */
194   unsigned char	r_info[4];	/* index and type of relocation */
195   unsigned char	r_addend[4];	/* Constant addend used to compute value */
196 } Elf32_External_Rela;
197 
198 typedef struct {
199   unsigned char r_data[4];	/* jump and bitmap for relative relocations */
200 } Elf32_External_Relr;
201 
202 typedef struct {
203   unsigned char r_offset[8];	/* Location at which to apply the action */
204   unsigned char	r_info[8];	/* index and type of relocation */
205 } Elf64_External_Rel;
206 
207 typedef struct {
208   unsigned char r_offset[8];	/* Location at which to apply the action */
209   unsigned char	r_info[8];	/* index and type of relocation */
210   unsigned char	r_addend[8];	/* Constant addend used to compute value */
211 } Elf64_External_Rela;
212 
213 typedef struct {
214   unsigned char r_data[8];	/* jump and bitmap for relative relocations */
215 } Elf64_External_Relr;
216 
217 /* dynamic section structure */
218 
219 typedef struct {
220   unsigned char	d_tag[4];		/* entry tag value */
221   union {
222     unsigned char	d_val[4];
223     unsigned char	d_ptr[4];
224   } d_un;
225 } Elf32_External_Dyn;
226 
227 typedef struct {
228   unsigned char	d_tag[8];		/* entry tag value */
229   union {
230     unsigned char	d_val[8];
231     unsigned char	d_ptr[8];
232   } d_un;
233 } Elf64_External_Dyn;
234 
235 /* The version structures are currently size independent.  They are
236    named without a 32 or 64.  If that ever changes, these structures
237    will need to be renamed.  */
238 
239 /* This structure appears in a SHT_GNU_verdef section.  */
240 
241 typedef struct {
242   unsigned char		vd_version[2];
243   unsigned char		vd_flags[2];
244   unsigned char		vd_ndx[2];
245   unsigned char		vd_cnt[2];
246   unsigned char		vd_hash[4];
247   unsigned char		vd_aux[4];
248   unsigned char		vd_next[4];
249 } Elf_External_Verdef;
250 
251 /* This structure appears in a SHT_GNU_verdef section.  */
252 
253 typedef struct {
254   unsigned char		vda_name[4];
255   unsigned char		vda_next[4];
256 } Elf_External_Verdaux;
257 
258 /* This structure appears in a SHT_GNU_verneed section.  */
259 
260 typedef struct {
261   unsigned char		vn_version[2];
262   unsigned char		vn_cnt[2];
263   unsigned char		vn_file[4];
264   unsigned char		vn_aux[4];
265   unsigned char		vn_next[4];
266 } Elf_External_Verneed;
267 
268 /* This structure appears in a SHT_GNU_verneed section.  */
269 
270 typedef struct {
271   unsigned char		vna_hash[4];
272   unsigned char		vna_flags[2];
273   unsigned char		vna_other[2];
274   unsigned char		vna_name[4];
275   unsigned char		vna_next[4];
276 } Elf_External_Vernaux;
277 
278 /* This structure appears in a SHT_GNU_versym section.  This is not a
279    standard ELF structure; ELF just uses Elf32_Half.  */
280 
281 typedef struct {
282   unsigned char		vs_vers[2];
283 } ATTRIBUTE_PACKED  Elf_External_Versym;
284 
285 /* Structure for syminfo section.  */
286 typedef struct
287 {
288   unsigned char		si_boundto[2];
289   unsigned char		si_flags[2];
290 } Elf_External_Syminfo;
291 
292 
293 /* This structure appears on the stack and in NT_AUXV core file notes.  */
294 typedef struct
295 {
296   unsigned char		a_type[4];
297   unsigned char		a_val[4];
298 } Elf32_External_Auxv;
299 
300 typedef struct
301 {
302   unsigned char		a_type[8];
303   unsigned char		a_val[8];
304 } Elf64_External_Auxv;
305 
306 /* Size of SHT_GROUP section entry.  */
307 
308 #define GRP_ENTRY_SIZE		4
309 
310 #endif /* _ELF_EXTERNAL_H */
311