1 /* Copyright (C) 1999-2020 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Andreas Jaeger <aj@suse.de>, 1999 and
4 Jakub Jelinek <jakub@redhat.com>, 1999.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
20 /* This code is a heavily simplified version of the readelf program
21 that's part of the current binutils development version. For architectures
22 which need to handle both 32bit and 64bit ELF libraries, this file is
23 included twice for each arch size. */
25 /* check_ptr checks that a pointer is in the mmaped file and doesn't
28 #define check_ptr(ptr) \
31 if ((void *)(ptr) < file_contents \
32 || (void *)(ptr) > (file_contents+file_length)) \
34 error (0, 0, _("file %s is truncated\n"), file_name); \
40 /* Returns 0 if everything is ok, != 0 in case of error. */
42 process_elf_file (const char *file_name
, const char *lib
, int *flag
,
43 unsigned int *osversion
, char **soname
, void *file_contents
,
48 unsigned int dynamic_addr
;
50 char *program_interpreter
;
52 ElfW(Ehdr
) *elf_header
;
53 ElfW(Phdr
) *elf_pheader
, *segment
;
54 ElfW(Dyn
) *dynamic_segment
, *dyn_entry
;
55 char *dynamic_strings
;
57 elf_header
= (ElfW(Ehdr
) *) file_contents
;
60 if (elf_header
->e_ident
[EI_CLASS
] != ElfW (CLASS
))
64 if (elf_header
->e_ident
[EI_CLASS
] == ELFCLASS32
)
65 error (0, 0, _("%s is a 32 bit ELF file.\n"), file_name
);
66 else if (elf_header
->e_ident
[EI_CLASS
] == ELFCLASS64
)
67 error (0, 0, _("%s is a 64 bit ELF file.\n"), file_name
);
69 error (0, 0, _("Unknown ELFCLASS in file %s.\n"), file_name
);
74 if (elf_header
->e_type
!= ET_DYN
)
76 error (0, 0, _("%s is not a shared object file (Type: %d).\n"), file_name
,
81 /* Get information from elf program header. */
82 elf_pheader
= (ElfW(Phdr
) *) (elf_header
->e_phoff
+ file_contents
);
83 check_ptr (elf_pheader
);
85 /* The library is an elf library, now search for soname and
91 program_interpreter
= NULL
;
92 for (i
= 0, segment
= elf_pheader
;
93 i
< elf_header
->e_phnum
; i
++, segment
++)
97 switch (segment
->p_type
)
101 error (0, 0, _("more than one dynamic segment\n"));
103 dynamic_addr
= segment
->p_offset
;
104 dynamic_size
= segment
->p_filesz
;
108 program_interpreter
= (char *) (file_contents
+ segment
->p_offset
);
109 check_ptr (program_interpreter
);
111 /* Check if this is enough to classify the binary. */
112 for (j
= 0; j
< sizeof (interpreters
) / sizeof (interpreters
[0]);
114 if (strcmp (program_interpreter
, interpreters
[j
].soname
) == 0)
116 *flag
= interpreters
[j
].flag
;
122 if (!*osversion
&& segment
->p_filesz
>= 32 && segment
->p_align
>= 4)
124 ElfW(Word
) *abi_note
= (ElfW(Word
) *) (file_contents
125 + segment
->p_offset
);
126 ElfW(Addr
) size
= segment
->p_filesz
;
127 /* NB: Some PT_NOTE segment may have alignment value of 0
128 or 1. gABI specifies that PT_NOTE segments should be
129 aligned to 4 bytes in 32-bit objects and to 8 bytes in
130 64-bit objects. As a Linux extension, we also support
131 4 byte alignment in 64-bit objects. If p_align is less
132 than 4, we treate alignment as 4 bytes since some note
133 segments have 0 or 1 byte alignment. */
134 ElfW(Addr
) align
= segment
->p_align
;
137 else if (align
!= 4 && align
!= 8)
140 while (abi_note
[0] != 4 || abi_note
[1] != 16
142 || memcmp (abi_note
+ 3, "GNU", 4) != 0)
145 = ELF_NOTE_NEXT_OFFSET (abi_note
[0], abi_note
[1],
148 if (size
- 32 < note_size
|| note_size
== 0)
154 abi_note
= (void *) abi_note
+ note_size
;
160 *osversion
= ((abi_note
[4] << 24)
161 | ((abi_note
[5] & 0xff) << 16)
162 | ((abi_note
[6] & 0xff) << 8)
163 | (abi_note
[7] & 0xff));
173 /* Now we can read the dynamic sections. */
174 if (dynamic_size
== 0)
177 dynamic_segment
= (ElfW(Dyn
) *) (file_contents
+ dynamic_addr
);
178 check_ptr (dynamic_segment
);
180 /* Find the string table. */
181 dynamic_strings
= NULL
;
182 for (dyn_entry
= dynamic_segment
; dyn_entry
->d_tag
!= DT_NULL
;
185 check_ptr (dyn_entry
);
186 if (dyn_entry
->d_tag
== DT_STRTAB
)
188 /* Find the file offset of the segment containing the dynamic
190 ElfW(Off
) loadoff
= -1;
191 for (i
= 0, segment
= elf_pheader
;
192 i
< elf_header
->e_phnum
; i
++, segment
++)
194 if (segment
->p_type
== PT_LOAD
195 && dyn_entry
->d_un
.d_val
>= segment
->p_vaddr
196 && (dyn_entry
->d_un
.d_val
- segment
->p_vaddr
197 < segment
->p_filesz
))
199 loadoff
= segment
->p_vaddr
- segment
->p_offset
;
203 if (loadoff
== (ElfW(Off
)) -1)
209 dynamic_strings
= (char *) (file_contents
+ dyn_entry
->d_un
.d_val
211 check_ptr (dynamic_strings
);
216 if (dynamic_strings
== NULL
)
219 /* Now read the DT_NEEDED and DT_SONAME entries. */
220 for (dyn_entry
= dynamic_segment
; dyn_entry
->d_tag
!= DT_NULL
;
223 if (dyn_entry
->d_tag
== DT_NEEDED
|| dyn_entry
->d_tag
== DT_SONAME
)
225 char *name
= dynamic_strings
+ dyn_entry
->d_un
.d_val
;
228 if (dyn_entry
->d_tag
== DT_NEEDED
)
231 if (*flag
== FLAG_ELF
)
233 /* Check if this is enough to classify the binary. */
235 j
< sizeof (known_libs
) / sizeof (known_libs
[0]);
237 if (strcmp (name
, known_libs
[j
].soname
) == 0)
239 *flag
= known_libs
[j
].flag
;
245 else if (dyn_entry
->d_tag
== DT_SONAME
)
246 *soname
= xstrdup (name
);
248 /* Do we have everything we need? */
249 if (*soname
&& *flag
!= FLAG_ELF
)