1 /* Copyright (C) 1999-2024 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library 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 GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
18 #include <elf-read-prop.h>
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 *isa_level
, char **soname
, void *file_contents
,
47 unsigned int dynamic_addr
;
49 char *program_interpreter
;
51 ElfW(Ehdr
) *elf_header
;
52 ElfW(Phdr
) *elf_pheader
, *segment
;
53 ElfW(Dyn
) *dynamic_segment
, *dyn_entry
;
54 char *dynamic_strings
;
56 elf_header
= (ElfW(Ehdr
) *) file_contents
;
58 if (elf_header
->e_ident
[EI_CLASS
] != ElfW (CLASS
))
62 if (elf_header
->e_ident
[EI_CLASS
] == ELFCLASS32
)
63 error (0, 0, _("%s is a 32 bit ELF file.\n"), file_name
);
64 else if (elf_header
->e_ident
[EI_CLASS
] == ELFCLASS64
)
65 error (0, 0, _("%s is a 64 bit ELF file.\n"), file_name
);
67 error (0, 0, _("Unknown ELFCLASS in file %s.\n"), file_name
);
72 if (elf_header
->e_type
!= ET_DYN
)
74 error (0, 0, _("%s is not a shared object file (Type: %d).\n"), file_name
,
79 /* Get information from elf program header. */
80 elf_pheader
= (ElfW(Phdr
) *) (elf_header
->e_phoff
+ file_contents
);
81 check_ptr (elf_pheader
);
83 /* The library is an elf library. */
84 *flag
= FLAG_ELF_LIBC6
;
86 /* The default ISA level is 0. */
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
);
112 case PT_GNU_PROPERTY
:
113 /* The NT_GNU_PROPERTY_TYPE_0 note must be aligned to 4 bytes
114 in 32-bit objects and to 8 bytes in 64-bit objects. Skip
115 notes with incorrect alignment. */
116 if (segment
->p_align
== (__ELF_NATIVE_CLASS
/ 8))
118 const ElfW(Nhdr
) *note
= (const void *) (file_contents
119 + segment
->p_offset
);
120 const ElfW(Addr
) size
= segment
->p_filesz
;
121 const ElfW(Addr
) align
= segment
->p_align
;
123 const ElfW(Addr
) start
= (ElfW(Addr
)) (uintptr_t) note
;
124 unsigned int last_type
= 0;
126 while ((ElfW(Addr
)) (uintptr_t) (note
+ 1) - start
< size
)
128 /* Find the NT_GNU_PROPERTY_TYPE_0 note. */
129 if (note
->n_namesz
== 4
130 && note
->n_type
== NT_GNU_PROPERTY_TYPE_0
131 && memcmp (note
+ 1, "GNU", 4) == 0)
133 /* Check for invalid property. */
134 if (note
->n_descsz
< 8
135 || (note
->n_descsz
% sizeof (ElfW(Addr
))) != 0)
138 /* Start and end of property array. */
139 unsigned char *ptr
= (unsigned char *) (note
+ 1) + 4;
140 unsigned char *ptr_end
= ptr
+ note
->n_descsz
;
144 unsigned int type
= *(unsigned int *) ptr
;
145 unsigned int datasz
= *(unsigned int *) (ptr
+ 4);
147 /* Property type must be in ascending order. */
148 if (type
< last_type
)
152 if ((ptr
+ datasz
) > ptr_end
)
157 /* Target specific property processing.
159 false: Continue processing the properties.
160 true : Stop processing the properties.
162 if (read_gnu_property (isa_level
, type
,
166 /* Check the next property item. */
167 ptr
+= ALIGN_UP (datasz
, sizeof (ElfW(Addr
)));
169 while ((ptr_end
- ptr
) >= 8);
171 /* Only handle one NT_GNU_PROPERTY_TYPE_0. */
175 note
= ((const void *) note
176 + ELF_NOTE_NEXT_OFFSET (note
->n_namesz
,
190 /* Now we can read the dynamic sections. */
191 if (dynamic_size
== 0)
194 dynamic_segment
= (ElfW(Dyn
) *) (file_contents
+ dynamic_addr
);
195 check_ptr (dynamic_segment
);
197 /* Find the string table. */
198 dynamic_strings
= NULL
;
199 for (dyn_entry
= dynamic_segment
; dyn_entry
->d_tag
!= DT_NULL
;
202 check_ptr (dyn_entry
);
203 if (dyn_entry
->d_tag
== DT_STRTAB
)
205 /* Find the file offset of the segment containing the dynamic
207 ElfW(Off
) loadoff
= -1;
208 for (i
= 0, segment
= elf_pheader
;
209 i
< elf_header
->e_phnum
; i
++, segment
++)
211 if (segment
->p_type
== PT_LOAD
212 && dyn_entry
->d_un
.d_val
>= segment
->p_vaddr
213 && (dyn_entry
->d_un
.d_val
- segment
->p_vaddr
214 < segment
->p_filesz
))
216 loadoff
= segment
->p_vaddr
- segment
->p_offset
;
220 if (loadoff
== (ElfW(Off
)) -1)
226 dynamic_strings
= (char *) (file_contents
+ dyn_entry
->d_un
.d_val
228 check_ptr (dynamic_strings
);
233 if (dynamic_strings
== NULL
)
236 /* Now read the DT_SONAME entries. */
237 for (dyn_entry
= dynamic_segment
; dyn_entry
->d_tag
!= DT_NULL
;
240 if (dyn_entry
->d_tag
== DT_SONAME
)
242 char *name
= dynamic_strings
+ dyn_entry
->d_un
.d_val
;
244 *soname
= xstrdup (name
);