I need to find the size of an elf image for some computation. I have tried with the readelf utility on linux which gives the informations about the headers and section. I need to have the exact file size of the elf(on the whole).
How do I find the size of the ELF from the header information or Is there any other means to find the size of an elf without reading the full image.
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Answer
You can use the stat
functions family (stat()
, lstat()
, fstat()
) to get the size of any file (using the st_size
member of the stat
member).
Do you need something more specific?
If you really want to use the ELF structure, use the elf.h header which contains that structure:
typedef struct { unsigned char e_ident[EI_NIDENT]; uint16_t e_type; uint16_t e_machine; uint32_t e_version; ElfN_Addr e_entry; ElfN_Off e_phoff; ElfN_Off e_shoff; uint32_t e_flags; uint16_t e_ehsize; uint16_t e_phentsize; uint16_t e_phnum; uint16_t e_shentsize; uint16_t e_shnum; uint16_t e_shstrndx; } Elf32_Ehdr;
It’s the header of an ELF32 file (replace 32 with 64 for a 64-bit file).
e_ehsize
is the size of the file in bytes.
I’ll copy verbatim the comment that was posted as an edit suggestion:
This answer is incorrect. e_ehsize is merely the size of the elf header, not the elf file.