b54d7a9715
Highlights: - Make sure that only TLS sections are sorted into TLS segment. - Fixed multiple errors in "Section to Segment mapping". - Man page updates - ar improvements - elfcopy: avoid filter_reloc uninitialized variable for rela - elfcopy: avoid stripping relocations from static binaries - readelf: avoid printing directory in front of absolute path - readelf: add NT_FREEBSD_FEATURE_CTL FreeBSD note type - test improvements NOTES: Some of these changes originated in FreeBSD and simply reduce diffs between contrib and vendor. ELF Tool Chain ar is not (currently) used in FreeBSD, and there are improvements in both FreeBSD and ELF Tool Chain ar that are not in the other. Sponsored by: The FreeBSD Foundation
201 lines
6.3 KiB
Groff
201 lines
6.3 KiB
Groff
.\" Copyright (c) 2006,2008 Joseph Koshy. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" This software is provided by Joseph Koshy ``as is'' and
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.\" any express or implied warranties, including, but not limited to, the
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.\" implied warranties of merchantability and fitness for a particular purpose
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.\" are disclaimed. in no event shall Joseph Koshy be liable
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.\" for any direct, indirect, incidental, special, exemplary, or consequential
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.\" damages (including, but not limited to, procurement of substitute goods
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.\" or services; loss of use, data, or profits; or business interruption)
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.\" however caused and on any theory of liability, whether in contract, strict
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.\" liability, or tort (including negligence or otherwise) arising in any way
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.\" out of the use of this software, even if advised of the possibility of
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.\" such damage.
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.\"
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.\" $Id: gelf.3 3643 2018-10-14 21:09:24Z jkoshy $
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.\"
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.Dd September 1, 2006
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.Dt GELF 3
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.Os
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.Sh NAME
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.Nm GElf
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.Nd class-independent API for ELF manipulation
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.Sh LIBRARY
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.Lb libelf
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.Sh SYNOPSIS
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.In gelf.h
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.Sh DESCRIPTION
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This manual page describes a class independent API for manipulating
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ELF objects.
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This API allows an application to operate on ELF descriptors without
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needing to the know the ELF class of the descriptor.
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.Pp
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The GElf API may be used alongside the ELF API without restriction.
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.Ss GElf Data Structures
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The GElf API defines the following class-independent data structures:
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.Bl -tag -width GElf_Sxword
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.It Vt GElf_Addr
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A representation of ELF addresses.
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.It Vt GElf_Dyn
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A class-independent representation of ELF
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.Sy .dynamic
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section entries.
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.It Vt GElf_Ehdr
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A class-independent representation of an ELF Executable Header.
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.It Vt GElf_Half
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An unsigned 16 bit quantity.
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.It Vt GElf_Off
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A class-independent representation of a ELF offset.
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.It Vt GElf_Phdr
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A class-independent representation of an ELF Program Header Table
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entry.
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.It Vt GElf_Rel
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A class-independent representation of an ELF relocation entry.
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.It Vt GElf_Rela
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A class-independent representation of an ELF relocation entry with
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addend.
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.It Vt GElf_Shdr
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A class-independent representation of an ELF Section Header Table
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entry.
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.It Vt GElf_Sword
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A signed 32 bit quantity.
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.It Vt GElf_Sxword
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A signed 64 bit quantity.
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.It Vt GElf_Sym
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A class-independent representation of an ELF symbol table entry.
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.It Vt GElf_Word
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An unsigned 32 bit quantity.
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.It Vt GElf_Xword
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An unsigned 64 bit quantity.
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.El
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.Pp
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These data structures are sized to be compatible with the
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corresponding 64 bit ELF structures, and have the same internal
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structure as their 64 bit class-dependent counterparts.
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Class-dependent ELF structures are described in
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.Xr elf 5 .
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.Ss GElf Programming Model
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GElf functions always return a
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.Em copy
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of the underlying (class-dependent) ELF data structure.
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The programming model with GElf is as follows:
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.Bl -enum
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.It
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An application will retrieve data from an ELF descriptor using a
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.Fn gelf_get_*
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function.
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This will copy out data into a private
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.Vt GElf_*
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data structure.
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.It
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The application will work with its private copy of the GElf
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structure.
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.It
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Once done, the application copies the new values back to the
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underlying ELF data structure using the
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.Fn gelf_update_*
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functions.
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.It
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The application will then use the
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.Fn elf_flag*
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APIs to indicate to the ELF library that an ELF data structure is dirty.
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.El
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.Pp
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When updating an underlying 32 bit ELF data structure, the GElf
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routines will signal an error if a GElf value is out of range
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for the underlying ELF data type.
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.Ss Namespace use
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The GElf interface uses the following symbols:
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.Bl -tag -width indent
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.It GElf_*
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Class-independent data types.
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.It gelf_*
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For functions defined in the API set.
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.El
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.Ss GElf Programming APIs
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This section provides an overview of the GElf programming APIs.
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Further information is provided in the manual page of each function
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listed here.
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.Bl -tag -width indent
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.It "Allocating ELF Data Structures"
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.Bl -tag -compact -width indent
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.It Fn gelf_newehdr
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Allocate a new ELF Executable Header.
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.It Fn gelf_newphdr
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Allocate a new ELF Program Header Table.
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.El
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.It "Data Translation"
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.Bl -tag -compact -width indent
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.It Fn gelf_xlatetof
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Translate the native representation of an ELF data structure to its
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file representation.
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.It Fn gelf_xlatetom
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Translate from the file representation of an ELF data structure to a
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native representation.
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.El
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.It "Retrieving ELF Data"
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.Bl -tag -compact -width indent
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.It Fn gelf_getdyn
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Retrieve an ELF
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.Sy .dynamic
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table entry.
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.It Fn gelf_getehdr
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Retrieve an ELF Executable Header from the underlying ELF descriptor.
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.It Fn gelf_getphdr
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Retrieve an ELF Program Header Table entry from the underlying ELF descriptor.
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.It Fn gelf_getrel
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Retrieve an ELF relocation entry.
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.It Fn gelf_getrela
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Retrieve an ELF relocation entry with addend.
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.It Fn gelf_getshdr
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Retrieve an ELF Section Header Table entry from the underlying ELF descriptor.
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.It Fn gelf_getsym
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Retrieve an ELF symbol table entry.
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.El
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.It Queries
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.Bl -tag -compact -width indent
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.It Fn gelf_checksum
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Retrieves the ELF checksum for an ELF descriptor.
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.It Fn gelf_fsize
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Retrieves the size of the file representation of an ELF type.
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.It Fn gelf_getclass
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Retrieves the ELF class of an ELF descriptor.
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.El
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.It "Updating ELF Data"
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.Bl -tag -compact -width ".Fn gelf_update_shdr"
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.It Fn gelf_update_dyn
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Copy back an ELF
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.Sy .dynamic
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Table entry.
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.It Fn gelf_update_phdr
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Copy back an ELF Program Header Table entry.
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.It Fn gelf_update_rel
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Copy back an ELF relocation entry.
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.It Fn gelf_update_rela
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Copy back an ELF relocation with addend entry.
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.It Fn gelf_update_shdr
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Copy back an ELF Section Header Table entry.
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.It Fn gelf_update_sym
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Copy back an ELF symbol table entry.
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.El
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.El
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.Sh SEE ALSO
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.Xr elf 3 ,
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.Xr elf 5
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.Sh HISTORY
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The GELF(3) API first appeared in System V Release 4.
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This implementation of the API first appeared in
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.Fx 7.0 .
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.Sh AUTHORS
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The GElf API was implemented by
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.An Joseph Koshy Aq Mt jkoshy@FreeBSD.org .
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