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1 /*
2  * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version 2
7  * of the License, or (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #ifndef _OBJTOOL_ELF_H
19 #define _OBJTOOL_ELF_H
20 
21 #include <stdio.h>
22 #include <gelf.h>
23 #include <linux/list.h>
24 #include <linux/hashtable.h>
25 
26 #ifdef LIBELF_USE_DEPRECATED
27 # define elf_getshdrnum    elf_getshnum
28 # define elf_getshdrstrndx elf_getshstrndx
29 #endif
30 
31 /*
32  * Fallback for systems without this "read, mmaping if possible" cmd.
33  */
34 #ifndef ELF_C_READ_MMAP
35 #define ELF_C_READ_MMAP ELF_C_READ
36 #endif
37 
38 struct section {
39 	struct list_head list;
40 	GElf_Shdr sh;
41 	struct list_head symbol_list;
42 	DECLARE_HASHTABLE(symbol_hash, 8);
43 	struct list_head rela_list;
44 	DECLARE_HASHTABLE(rela_hash, 16);
45 	struct section *base, *rela;
46 	struct symbol *sym;
47 	Elf_Data *data;
48 	char *name;
49 	int idx;
50 	unsigned int len;
51 	bool changed, text, rodata;
52 };
53 
54 struct symbol {
55 	struct list_head list;
56 	struct hlist_node hash;
57 	GElf_Sym sym;
58 	struct section *sec;
59 	char *name;
60 	unsigned int idx;
61 	unsigned char bind, type;
62 	unsigned long offset;
63 	unsigned int len;
64 	struct symbol *pfunc, *cfunc;
65 };
66 
67 struct rela {
68 	struct list_head list;
69 	struct hlist_node hash;
70 	GElf_Rela rela;
71 	struct section *rela_sec;
72 	struct symbol *sym;
73 	unsigned int type;
74 	unsigned long offset;
75 	int addend;
76 };
77 
78 struct elf {
79 	Elf *elf;
80 	GElf_Ehdr ehdr;
81 	int fd;
82 	char *name;
83 	struct list_head sections;
84 	DECLARE_HASHTABLE(rela_hash, 16);
85 };
86 
87 
88 struct elf *elf_open(const char *name, int flags);
89 struct section *find_section_by_name(struct elf *elf, const char *name);
90 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
91 struct symbol *find_symbol_by_name(struct elf *elf, const char *name);
92 struct symbol *find_symbol_containing(struct section *sec, unsigned long offset);
93 struct rela *find_rela_by_dest(struct section *sec, unsigned long offset);
94 struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
95 				     unsigned int len);
96 struct symbol *find_containing_func(struct section *sec, unsigned long offset);
97 struct section *elf_create_section(struct elf *elf, const char *name, size_t
98 				   entsize, int nr);
99 struct section *elf_create_rela_section(struct elf *elf, struct section *base);
100 int elf_rebuild_rela_section(struct section *sec);
101 int elf_write(struct elf *elf);
102 void elf_close(struct elf *elf);
103 
104 #define for_each_sec(file, sec)						\
105 	list_for_each_entry(sec, &file->elf->sections, list)
106 
107 #endif /* _OBJTOOL_ELF_H */
108