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How to extract function prototypes from an elf file?

I could not find the answer to this question.

Using GDB, I can use the "call" command to get a function prototype. Example:

(gdb) call fn
$1 = {void (int, int)} 0x8048414 <fn>

So, GDB can only calculate from the file elf that fn () returns void and takes two integers as arguments.

However, I need to use another tool to extract function prototypes from an elf file. Preferably, I want to use objdump / readelf.

Does anyone know if this is possible? If this is not possible, how does GDB do it? In which section of the elf file are stored prototypes of functions stored?

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GDB DWARF debuginfo. readelf -w ELF . , DWARF Michael J. Eager. pyelftools, DWARF Python.

, subprogram. DWARF:

strndup.c

 1: #include "ansidecl.h"
 2: #include <stddef.h>
 3:
 4: extern size_t strlen (const char*);
 5: extern PTR malloc (size_t);
 6: extern PTR memcpy (PTR, const PTR, size_t);
 7:
 8: char *
 9: strndup (const char *s, size_t n)
10: {
11: char *result;
12: size_t len = strlen (s);
13:
14: if (n < len)
15: len = n;
16:
17: result = (char *) malloc (len + 1);
18: if (!result)
19: return 0;
20:
21: result[len] = '\0';
22: return (char *) memcpy (result, s, len);
23: }

DWARF strndup.c

<1>: DW_TAG_base_type
   DW_AT_name = int
   DW_AT_byte_size = 4
   DW_AT_encoding = signed
<2>: DW_TAG_typedef
   DW_AT_name = size_t
   DW_AT_type = <3>
<3>: DW_TAG_base_type
   DW_AT_name = unsigned int
   DW_AT_byte_size = 4
   DW_AT_encoding = unsigned
<4>: DW_TAG_base_type
   DW_AT_name = long int
   DW_AT_byte_size = 4
   DW_AT_encoding = signed
<5>: DW_TAG_subprogram
   DW_AT_sibling = <10>
   DW_AT_external = 1
   DW_AT_name = strndup
   DW_AT_prototyped = 1
   DW_AT_type = <10>
   DW_AT_low_pc = 0
   DW_AT_high_pc = 0x7b
<6>: DW_TAG_formal_parameter
   DW_AT_name = s
   DW_AT_type = <12>
   DW_AT_location =
   (DW_OP_fbreg: 0)
<7>: DW_TAG_formal_parameter
   DW_AT_name = n
   DW_AT_type = <2>
   DW_AT_location =
   (DW_OP_fbreg: 4)
<8>: DW_TAG_variable
   DW_AT_name = result
   DW_AT_type = <10>
   DW_AT_location =
   (DW_OP_fbreg: -28)
<9>: DW_TAG_variable
   DW_AT_name = len
   DW_AT_type = <2>
   DW_AT_location =
   (DW_OP_fbreg: -24)
<10>: DW_TAG_pointer_type
   DW_AT_byte_size = 4
   DW_AT_type = <11>
<11>: DW_TAG_base_type
   DW_AT_name = char
   DW_AT_byte_size = 1
   DW_AT_encoding =
   signed char
<12>: DW_TAG_pointer_type
   DW_AT_byte_size = 4
   DW_AT_type = <13>
<13>: DW_TAG_const_type
   DW_AT_type = <11>

C . , , :

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