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5191 serge 1
/* ELF support for BFD.
6324 serge 2
   Copyright (C) 1991-2015 Free Software Foundation, Inc.
5191 serge 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 internally in the BFD library.
27
   I.E. it describes the in-memory 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
/* NOTE that these structures are not kept in the same order as they appear
32
   in the object file.  In some cases they've been reordered for more optimal
33
   packing under various circumstances.  */
34
 
35
#ifndef _ELF_INTERNAL_H
36
#define _ELF_INTERNAL_H
37
 
38
/* Special section indices, which may show up in st_shndx fields, among
39
   other places.  */
40
 
41
#undef SHN_UNDEF
42
#undef SHN_LORESERVE
43
#undef SHN_LOPROC
44
#undef SHN_HIPROC
45
#undef SHN_LOOS
46
#undef SHN_HIOS
47
#undef SHN_ABS
48
#undef SHN_COMMON
49
#undef SHN_XINDEX
50
#undef SHN_HIRESERVE
51
#define SHN_UNDEF	0		/* Undefined section reference */
52
#define SHN_LORESERVE	(-0x100u)	/* Begin range of reserved indices */
53
#define SHN_LOPROC	(-0x100u)	/* Begin range of appl-specific */
54
#define SHN_HIPROC	(-0xE1u)	/* End range of appl-specific */
55
#define SHN_LOOS	(-0xE0u)	/* OS specific semantics, lo */
56
#define SHN_HIOS	(-0xC1u)	/* OS specific semantics, hi */
57
#define SHN_ABS		(-0xFu)		/* Associated symbol is absolute */
58
#define SHN_COMMON	(-0xEu)		/* Associated symbol is in common */
59
#define SHN_XINDEX	(-0x1u)		/* Section index is held elsewhere */
60
#define SHN_HIRESERVE	(-0x1u)		/* End range of reserved indices */
61
#define SHN_BAD		(-0x101u)	/* Used internally by bfd */
62
 
63
/* ELF Header */
64
 
65
#define EI_NIDENT	16		/* Size of e_ident[] */
66
 
67
typedef struct elf_internal_ehdr {
68
  unsigned char		e_ident[EI_NIDENT]; /* ELF "magic number" */
69
  bfd_vma		e_entry;	/* Entry point virtual address */
70
  bfd_size_type		e_phoff;	/* Program header table file offset */
71
  bfd_size_type		e_shoff;	/* Section header table file offset */
72
  unsigned long		e_version;	/* Identifies object file version */
73
  unsigned long		e_flags;	/* Processor-specific flags */
74
  unsigned short	e_type;		/* Identifies object file type */
75
  unsigned short	e_machine;	/* Specifies required architecture */
76
  unsigned int		e_ehsize;	/* ELF header size in bytes */
77
  unsigned int		e_phentsize;	/* Program header table entry size */
78
  unsigned int		e_phnum;	/* Program header table entry count */
79
  unsigned int		e_shentsize;	/* Section header table entry size */
80
  unsigned int		e_shnum;	/* Section header table entry count */
81
  unsigned int		e_shstrndx;	/* Section header string table index */
82
} Elf_Internal_Ehdr;
83
 
84
/* Program header */
85
 
86
struct elf_internal_phdr {
87
  unsigned long	p_type;			/* Identifies program segment type */
88
  unsigned long	p_flags;		/* Segment flags */
89
  bfd_vma	p_offset;		/* Segment file offset */
90
  bfd_vma	p_vaddr;		/* Segment virtual address */
91
  bfd_vma	p_paddr;		/* Segment physical address */
92
  bfd_vma	p_filesz;		/* Segment size in file */
93
  bfd_vma	p_memsz;		/* Segment size in memory */
94
  bfd_vma	p_align;		/* Segment alignment, file & memory */
95
};
96
 
97
typedef struct elf_internal_phdr Elf_Internal_Phdr;
98
 
99
/* Section header */
100
 
101
typedef struct elf_internal_shdr {
102
  unsigned int	sh_name;		/* Section name, index in string tbl */
103
  unsigned int	sh_type;		/* Type of section */
104
  bfd_vma	sh_flags;		/* Miscellaneous section attributes */
105
  bfd_vma	sh_addr;		/* Section virtual addr at execution */
106
  file_ptr	sh_offset;		/* Section file offset */
107
  bfd_size_type	sh_size;		/* Size of section in bytes */
108
  unsigned int	sh_link;		/* Index of another section */
109
  unsigned int	sh_info;		/* Additional section information */
110
  bfd_vma	sh_addralign;		/* Section alignment */
111
  bfd_size_type	sh_entsize;		/* Entry size if section holds table */
112
 
113
  /* The internal rep also has some cached info associated with it. */
114
  asection *	bfd_section;		/* Associated BFD section.  */
115
  unsigned char *contents;		/* Section contents.  */
116
} Elf_Internal_Shdr;
117
 
6324 serge 118
/* Compression header */
119
 
120
typedef struct elf_internal_chdr {
121
  unsigned int	ch_type;		/* Type of compression */
122
  bfd_size_type	ch_size;		/* Size of uncompressed data in bytes */
123
  bfd_vma	ch_addralign;		/* Alignment of uncompressed data */
124
} Elf_Internal_Chdr;
125
 
5191 serge 126
/* Symbol table entry */
127
 
128
struct elf_internal_sym {
129
  bfd_vma	st_value;		/* Value of the symbol */
130
  bfd_vma	st_size;		/* Associated symbol size */
131
  unsigned long	st_name;		/* Symbol name, index in string tbl */
132
  unsigned char	st_info;		/* Type and binding attributes */
133
  unsigned char	st_other;		/* Visibilty, and target specific */
134
  unsigned char st_target_internal;	/* Internal-only information */
135
  unsigned int  st_shndx;		/* Associated section index */
136
};
137
 
138
typedef struct elf_internal_sym Elf_Internal_Sym;
139
 
140
/* Note segments */
141
 
142
typedef struct elf_internal_note {
143
  unsigned long	namesz;			/* Size of entry's owner string */
144
  unsigned long	descsz;			/* Size of the note descriptor */
145
  unsigned long	type;			/* Interpretation of the descriptor */
146
  char *	namedata;		/* Start of the name+desc data */
147
  char *	descdata;		/* Start of the desc data */
148
  bfd_vma	descpos;		/* File offset of the descdata */
149
} Elf_Internal_Note;
150
 
151
/* Relocation Entries */
152
 
153
typedef struct elf_internal_rela {
154
  bfd_vma	r_offset;	/* Location at which to apply the action */
155
  bfd_vma	r_info;		/* Index and Type of relocation */
156
  bfd_vma	r_addend;	/* Constant addend used to compute value */
157
} Elf_Internal_Rela;
158
 
159
/* dynamic section structure */
160
 
161
typedef struct elf_internal_dyn {
162
  /* This needs to support 64-bit values in elf64.  */
163
  bfd_vma d_tag;		/* entry tag value */
164
  union {
165
    /* This needs to support 64-bit values in elf64.  */
166
    bfd_vma	d_val;
167
    bfd_vma	d_ptr;
168
  } d_un;
169
} Elf_Internal_Dyn;
170
 
171
/* This structure appears in a SHT_GNU_verdef section.  */
172
 
173
typedef struct elf_internal_verdef {
174
  unsigned short vd_version;	/* Version number of structure.  */
175
  unsigned short vd_flags;	/* Flags (VER_FLG_*).  */
176
  unsigned short vd_ndx;	/* Version index.  */
177
  unsigned short vd_cnt;	/* Number of verdaux entries.  */
178
  unsigned long	 vd_hash;	/* Hash of name.  */
179
  unsigned long	 vd_aux;	/* Offset to verdaux entries.  */
180
  unsigned long	 vd_next;	/* Offset to next verdef.  */
181
 
182
  /* These fields are set up when BFD reads in the structure.  FIXME:
183
     It would be cleaner to store these in a different structure.  */
184
  bfd			      *vd_bfd;		/* BFD.  */
185
  const char		      *vd_nodename;	/* Version name.  */
186
  struct elf_internal_verdef  *vd_nextdef;	/* vd_next as pointer.  */
187
  struct elf_internal_verdaux *vd_auxptr;	/* vd_aux as pointer.  */
188
  unsigned int		       vd_exp_refno;	/* Used by the linker.  */
189
} Elf_Internal_Verdef;
190
 
191
/* This structure appears in a SHT_GNU_verdef section.  */
192
 
193
typedef struct elf_internal_verdaux {
194
  unsigned long vda_name;	/* String table offset of name.  */
195
  unsigned long vda_next;	/* Offset to next verdaux.  */
196
 
197
  /* These fields are set up when BFD reads in the structure.  FIXME:
198
     It would be cleaner to store these in a different structure.  */
199
  const char *vda_nodename;			/* vda_name as pointer.  */
200
  struct elf_internal_verdaux *vda_nextptr;	/* vda_next as pointer.  */
201
} Elf_Internal_Verdaux;
202
 
203
/* This structure appears in a SHT_GNU_verneed section.  */
204
 
205
typedef struct elf_internal_verneed {
206
  unsigned short vn_version;	/* Version number of structure.  */
207
  unsigned short vn_cnt;	/* Number of vernaux entries.  */
208
  unsigned long	 vn_file;	/* String table offset of library name.  */
209
  unsigned long	 vn_aux;	/* Offset to vernaux entries.  */
210
  unsigned long	 vn_next;	/* Offset to next verneed.  */
211
 
212
  /* These fields are set up when BFD reads in the structure.  FIXME:
213
     It would be cleaner to store these in a different structure.  */
214
  bfd			      *vn_bfd;		/* BFD.  */
215
  const char                  *vn_filename;	/* vn_file as pointer.  */
216
  struct elf_internal_vernaux *vn_auxptr;	/* vn_aux as pointer.  */
217
  struct elf_internal_verneed *vn_nextref;	/* vn_nextref as pointer.  */
218
} Elf_Internal_Verneed;
219
 
220
/* This structure appears in a SHT_GNU_verneed section.  */
221
 
222
typedef struct elf_internal_vernaux {
223
  unsigned long	 vna_hash;	/* Hash of dependency name.  */
224
  unsigned short vna_flags;	/* Flags (VER_FLG_*).  */
225
  unsigned short vna_other;	/* Unused.  */
226
  unsigned long	 vna_name;	/* String table offset to version name.  */
227
  unsigned long	 vna_next;	/* Offset to next vernaux.  */
228
 
229
  /* These fields are set up when BFD reads in the structure.  FIXME:
230
     It would be cleaner to store these in a different structure.  */
231
  const char                  *vna_nodename;	/* vna_name as pointer.  */
232
  struct elf_internal_vernaux *vna_nextptr;	/* vna_next as pointer.  */
233
} Elf_Internal_Vernaux;
234
 
235
/* This structure appears in a SHT_GNU_versym section.  This is not a
236
   standard ELF structure; ELF just uses Elf32_Half.  */
237
 
238
typedef struct elf_internal_versym {
239
  unsigned short vs_vers;
240
} Elf_Internal_Versym;
241
 
242
/* Structure for syminfo section.  */
243
typedef struct
244
{
245
  unsigned short int 	si_boundto;
246
  unsigned short int	si_flags;
247
} Elf_Internal_Syminfo;
248
 
249
/* This structure appears on the stack and in NT_AUXV core file notes.  */
250
typedef struct
251
{
252
  bfd_vma a_type;
253
  bfd_vma a_val;
254
} Elf_Internal_Auxv;
255
 
256
 
257
/* This structure is used to describe how sections should be assigned
258
   to program segments.  */
259
 
260
struct elf_segment_map
261
{
262
  /* Next program segment.  */
263
  struct elf_segment_map *next;
264
  /* Program segment type.  */
265
  unsigned long p_type;
266
  /* Program segment flags.  */
267
  unsigned long p_flags;
268
  /* Program segment physical address.  */
269
  bfd_vma p_paddr;
270
  /* Program segment virtual address offset from section vma.  */
271
  bfd_vma p_vaddr_offset;
272
  /* Program segment alignment.  */
273
  bfd_vma p_align;
274
  /* Segment size in file and memory */
275
  bfd_vma p_size;
276
  /* Required size of filehdr + phdrs, if non-zero */
277
  bfd_vma header_size;
278
  /* Whether the p_flags field is valid; if not, the flags are based
279
     on the section flags.  */
280
  unsigned int p_flags_valid : 1;
281
  /* Whether the p_paddr field is valid; if not, the physical address
282
     is based on the section lma values.  */
283
  unsigned int p_paddr_valid : 1;
284
  /* Whether the p_align field is valid; if not, PT_LOAD segment
285
     alignment is based on the default maximum page size.  */
286
  unsigned int p_align_valid : 1;
287
  /* Whether the p_size field is valid; if not, the size are based
288
     on the section sizes.  */
289
  unsigned int p_size_valid : 1;
290
  /* Whether this segment includes the file header.  */
291
  unsigned int includes_filehdr : 1;
292
  /* Whether this segment includes the program headers.  */
293
  unsigned int includes_phdrs : 1;
294
  /* Number of sections (may be 0).  */
295
  unsigned int count;
296
  /* Sections.  Actual number of elements is in count field.  */
297
  asection *sections[1];
298
};
299
 
300
/* .tbss is special.  It doesn't contribute memory space to normal
301
   segments and it doesn't take file space in normal segments.  */
302
#define ELF_TBSS_SPECIAL(sec_hdr, segment)			\
303
  (((sec_hdr)->sh_flags & SHF_TLS) != 0				\
304
   && (sec_hdr)->sh_type == SHT_NOBITS				\
305
   && (segment)->p_type != PT_TLS)
306
 
307
#define ELF_SECTION_SIZE(sec_hdr, segment)			\
308
  (ELF_TBSS_SPECIAL(sec_hdr, segment) ? 0 : (sec_hdr)->sh_size)
309
 
310
/* Decide if the section SEC_HDR is in SEGMENT.  If CHECK_VMA, then
311
   VMAs are checked for alloc sections.  If STRICT, then a zero size
312
   section won't match at the end of a segment, unless the segment
313
   is also zero size.  Regardless of STRICT and CHECK_VMA, zero size
314
   sections won't match at the start or end of PT_DYNAMIC, unless
315
   PT_DYNAMIC is itself zero sized.  */
316
#define ELF_SECTION_IN_SEGMENT_1(sec_hdr, segment, check_vma, strict)	\
317
  ((/* Only PT_LOAD, PT_GNU_RELRO and PT_TLS segments can contain	\
318
       SHF_TLS sections.  */						\
319
    ((((sec_hdr)->sh_flags & SHF_TLS) != 0)				\
320
     && ((segment)->p_type == PT_TLS					\
321
	 || (segment)->p_type == PT_GNU_RELRO				\
322
	 || (segment)->p_type == PT_LOAD))				\
323
    /* PT_TLS segment contains only SHF_TLS sections, PT_PHDR no	\
324
       sections at all.  */						\
325
    || (((sec_hdr)->sh_flags & SHF_TLS) == 0				\
326
	&& (segment)->p_type != PT_TLS					\
327
	&& (segment)->p_type != PT_PHDR))				\
6324 serge 328
   /* PT_LOAD and similar segments only have SHF_ALLOC sections.  */	\
329
   && !(((sec_hdr)->sh_flags & SHF_ALLOC) == 0				\
330
	&& ((segment)->p_type == PT_LOAD				\
331
	    || (segment)->p_type == PT_DYNAMIC				\
332
	    || (segment)->p_type == PT_GNU_EH_FRAME			\
333
	    || (segment)->p_type == PT_GNU_RELRO			\
334
	    || (segment)->p_type == PT_GNU_STACK))			\
5191 serge 335
   /* Any section besides one of type SHT_NOBITS must have file		\
336
      offsets within the segment.  */					\
337
   && ((sec_hdr)->sh_type == SHT_NOBITS					\
338
       || ((bfd_vma) (sec_hdr)->sh_offset >= (segment)->p_offset	\
339
	   && (!(strict)						\
340
	       || ((sec_hdr)->sh_offset - (segment)->p_offset		\
341
		   <= (segment)->p_filesz - 1))				\
342
	   && (((sec_hdr)->sh_offset - (segment)->p_offset		\
343
		+ ELF_SECTION_SIZE(sec_hdr, segment))			\
344
	       <= (segment)->p_filesz)))				\
345
   /* SHF_ALLOC sections must have VMAs within the segment.  */		\
346
   && (!(check_vma)							\
347
       || ((sec_hdr)->sh_flags & SHF_ALLOC) == 0			\
348
       || ((sec_hdr)->sh_addr >= (segment)->p_vaddr			\
349
	   && (!(strict)						\
350
	       || ((sec_hdr)->sh_addr - (segment)->p_vaddr		\
351
		   <= (segment)->p_memsz - 1))				\
352
	   && (((sec_hdr)->sh_addr - (segment)->p_vaddr			\
353
		+ ELF_SECTION_SIZE(sec_hdr, segment))			\
354
	       <= (segment)->p_memsz)))					\
355
   /* No zero size sections at start or end of PT_DYNAMIC.  */		\
356
   && ((segment)->p_type != PT_DYNAMIC					\
357
       || (sec_hdr)->sh_size != 0					\
358
       || (segment)->p_memsz == 0					\
359
       || (((sec_hdr)->sh_type == SHT_NOBITS				\
360
	    || ((bfd_vma) (sec_hdr)->sh_offset > (segment)->p_offset	\
361
	        && ((sec_hdr)->sh_offset - (segment)->p_offset		\
362
		    < (segment)->p_filesz)))				\
363
	   && (((sec_hdr)->sh_flags & SHF_ALLOC) == 0			\
364
	       || ((sec_hdr)->sh_addr > (segment)->p_vaddr		\
365
		   && ((sec_hdr)->sh_addr - (segment)->p_vaddr		\
366
		       < (segment)->p_memsz))))))
367
 
368
#define ELF_SECTION_IN_SEGMENT(sec_hdr, segment)			\
369
  (ELF_SECTION_IN_SEGMENT_1 (sec_hdr, segment, 1, 0))
370
 
371
#define ELF_SECTION_IN_SEGMENT_STRICT(sec_hdr, segment)			\
372
  (ELF_SECTION_IN_SEGMENT_1 (sec_hdr, segment, 1, 1))
373
 
374
#endif /* _ELF_INTERNAL_H */