man pages section 3: Extended Library Functions, Volume 1

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Updated: July 2014
 
 

elf32_getphdr(3ELF)

Name

elf32_getphdr, elf32_newphdr, elf64_getphdr, elf64_newphdr - retrieve class-dependent program header table

Synopsis

cc [ flag ... ] file... –lelf [ library ... ]
#include <libelf.h>

Elf32_Phdr *elf32_getphdr(Elf *elf);
Elf32_Phdr *elf32_newphdr(Elf *elf, size_t count);
Elf64_Phdr *elf64_getphdr(Elf *elf);
Elf64_Phdr *elf64_newphdr(Elf *elf, size_t count);

Description

For a 32-bit class file, elf32_getphdr() returns a pointer to the program execution header table, if one is available for the ELF descriptor elf.

elf32_newphdr() allocates a new table with count entries, regardless of whether one existed previously, and sets the ELF_F_DIRTY bit for the table. See elf_flagdata(3ELF). Specifying a zero count deletes an existing table. Note this behavior differs from that of elf32_newehdr() allowing a program to replace or delete the program header table, changing its size if necessary. See elf32_getehdr(3ELF).

If no program header table exists, the file is not a 32-bit class file, an error occurs, or elf is NULL, both functions return a null pointer. Additionally, elf32_newphdr() returns a null pointer if count is 0.

The table is an array of Elf32_Phdr structures, each of which includes the following members:

Elf32_Word	p_type;
Elf32_Off	p_offset;
Elf32_Addr	p_vaddr;
Elf32_Addr	p_paddr;
Elf32_Word	p_filesz;
Elf32_Word	p_memsz;
Elf32_Word	p_flags;
Elf32_Word	p_align;

The Elf64_Phdr structures include the following members:

Elf64_Word	p_type;
Elf64_Word	p_flags;
Elf64_Off	p_offset;
Elf64_Addr	p_vaddr;
Elf64_Addr	p_paddr;
Elf64_Xword	p_filesz;
Elf64_Xword	p_memsz;
Elf64_Xword	p_align;

For the 64−bit class, replace 32 with 64 as appropriate.

The ELF header's e_phnum member tells how many entries the program header table has. See elf32_getehdr(3ELF). A program may inspect this value to determine the size of an existing table; elf32_newphdr() automatically sets the member's value to count. If the program is building a new file, it is responsible for creating the file's ELF header before creating the program header table.

Attributes

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Interface Stability
Committed
MT-Level
MT-Safe

See Also

elf(3ELF), elf32_getehdr(3ELF), elf_begin(3ELF), elf_flagdata(3ELF), libelf(3LIB), attributes (5)