.if defined(WITH_BUNDLED_LIBELF)

SUBDIR+= libelf

.endif

# $FreeBSD: head/lib/libelf/Makefile 238741 2012-07-24 16:03:28Z ache $

LIB=	elf

SRCS=	elf_begin.c						\

	elf_cntl.c						\

	elf_end.c elf_errmsg.c elf_errno.c			\

	elf_data.c						\

	elf_fill.c						\

	elf_flag.c						\

	elf_getarhdr.c						\

	elf_getarsym.c						\

	elf_getbase.c						\

	elf_getident.c						\

	elf_hash.c						\

	elf_kind.c						\

	elf_memory.c						\

	elf_next.c						\

	elf_rand.c						\

	elf_rawfile.c						\

	elf_phnum.c						\

	elf_shnum.c						\

	elf_shstrndx.c						\

	elf_scn.c						\

	elf_strptr.c						\

	elf_update.c						\

	elf_version.c						\

	gelf_cap.c						\

	gelf_checksum.c						\

	gelf_dyn.c						\

	gelf_ehdr.c						\

	gelf_getclass.c						\

	gelf_fsize.c						\

	gelf_move.c						\

	gelf_phdr.c						\

	gelf_rel.c						\

	gelf_rela.c						\

	gelf_shdr.c						\

	gelf_sym.c						\

	gelf_syminfo.c						\

	gelf_symshndx.c						\

	gelf_xlate.c						\

	libelf.c						\

	libelf_align.c						\

	libelf_allocate.c					\

	libelf_ar.c						\

	libelf_ar_util.c					\

	libelf_checksum.c					\

	libelf_data.c						\

	libelf_ehdr.c						\

	libelf_extended.c					\

	libelf_phdr.c						\

	libelf_shdr.c						\

	libelf_xlate.c						\

	${GENSRCS}

INTERNALLIB=

INCS=	libelf.h gelf.h

GENSRCS=	libelf_fsize.c libelf_msize.c libelf_convert.c

CLEANFILES=	${GENSRCS}

CLEANDIRS=	sys

CFLAGS+=	-I${.CURDIR} -I.

NO_MAN=	yes

libelf_convert.c:	elf_types.m4 libelf_convert.m4

libelf_fsize.c:		elf_types.m4 libelf_fsize.m4

libelf_msize.c:		elf_types.m4 libelf_msize.m4

.include <bsd.lib.mk>

# Keep the .SUFFIXES line after the include of bsd.lib.mk

.SUFFIXES:	.m4 .c

.m4.c:

	m4 -D SRCDIR=${.CURDIR} ${.IMPSRC} > ${.TARGET}

# $FreeBSD: releng/9.1/lib/libelf/README 186758 2009-01-05 05:14:26Z jkoshy $

# $NetBSD$

libelf: a BSD-licensed implementation of the ELF(3)/GELF(3) API.

Documentation:

 * Manual page elf.3 contains an overview of the library.  Other

   manual pages document individual APIs in the library.

 * A tutorial "libelf by Example" is available at:

   http://people.freebsd.org/~jkoshy/download/libelf/article.html

For ongoing development please see http://elftoolchain.sourceforge.net/

/*

 * $FreeBSD: releng/9.1/lib/libelf/Version.map 210345 2010-07-21 12:14:50Z kaiw $

 */

FBSD_1.0 {

global:

	elf32_checksum;

	elf32_fsize;

	elf32_getehdr;

	elf32_getphdr;

	elf32_getshdr;

	elf32_newehdr;

	elf32_newphdr;

	elf32_xlatetof;

	elf32_xlatetom;

	elf64_checksum;

	elf64_fsize;

	elf64_getehdr;

	elf64_getphdr;

	elf64_getshdr;

	elf64_newehdr;

	elf64_newphdr;

	elf64_xlatetof;

	elf64_xlatetom;

	elf_begin;

	elf_cntl;

	elf_end;

	elf_errmsg;

	elf_errno;

	elf_fill;

	elf_flagdata;

	elf_flagehdr;

	elf_flagelf;

	elf_flagphdr;

	elf_flagscn;

	elf_flagshdr;

	elf_getarhdr;

	elf_getarsym;

	elf_getbase;

	elf_getdata;

	elf_getident;

	elf_getscn;

	elf_getphdrnum;

	elf_getphnum;

	elf_getshdrnum;

	elf_getshnum;

	elf_getshdrstrndx;

	elf_getshstrndx;

	elf_hash;

	elf_kind;

	elf_memory;

	elf_ndxscn;

	elf_newdata;

	elf_newscn;

	elf_next;

	elf_nextscn;

	elf_rand;

	elf_rawdata;

	elf_rawfile;

	elf_setshstrndx;

	elf_strptr;

	elf_update;

	elf_version;

	gelf_checksum;

	gelf_fsize;

	gelf_getcap;

	gelf_getclass;

	gelf_getdyn;

	gelf_getehdr;

	gelf_getmove;

	gelf_getphdr;

	gelf_getrel;

	gelf_getrela;

	gelf_getshdr;

	gelf_getsym;

	gelf_getsyminfo;

	gelf_getsymshndx;

	gelf_newehdr;

	gelf_newphdr;

	gelf_update_cap;

	gelf_update_dyn;

	gelf_update_ehdr;

	gelf_update_move;

	gelf_update_phdr;

	gelf_update_rel;

	gelf_update_rela;

	gelf_update_shdr;

	gelf_update_sym;

	gelf_update_syminfo;

	gelf_update_symshndx;

	gelf_xlatetof;

	gelf_xlatetom;

local:

	*;

};

/*

 * Private symbols, mostly test hooks

 */

FBSDprivate_1.0 {

global:

	_libelf_set_error;

	_libelf_get_max_error;

	_libelf_get_no_error_message;

	_libelf_get_unknown_error_message;

};

/*-

 * Copyright (c) 2006 Joseph Koshy

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 * $FreeBSD: releng/9.1/lib/libelf/_libelf.h 210348 2010-07-21 12:54:34Z kaiw $

 */

#ifndef	__LIBELF_H_

#define	__LIBELF_H_

#include <sys/queue.h>

#ifndef	NULL

#define NULL 	((void *) 0)

#endif

/*

 * Library-private data structures.

 */

#define LIBELF_MSG_SIZE	256

struct _libelf_globals {

	int		libelf_arch;

	unsigned int	libelf_byteorder;

	int		libelf_class;

	int		libelf_error;

	int		libelf_fillchar;

	unsigned int	libelf_version;

	char		libelf_msg[LIBELF_MSG_SIZE];

};

extern struct _libelf_globals _libelf;

#define	LIBELF_PRIVATE(N)	(_libelf.libelf_##N)

#define	LIBELF_ELF_ERROR_MASK	0xFF

#define	LIBELF_OS_ERROR_SHIFT	8

#define	LIBELF_SET_ERROR(E, O) do {					\

	LIBELF_PRIVATE(error) = ((ELF_E_##E & LIBELF_ELF_ERROR_MASK)|	\

	    ((O) << LIBELF_OS_ERROR_SHIFT));				\

	} while (0)

#define	LIBELF_ADJUST_AR_SIZE(S)	(((S) + 1U) & ~1U)

/*

 * Flags for library internal use.  These use the upper 16 bits of a

 * flags field.

 */

#define	LIBELF_F_MALLOCED	0x010000 /* whether data was malloc'ed */

#define	LIBELF_F_MMAP		0x020000 /* whether e_rawfile was mmap'ed */

#define	LIBELF_F_SHDRS_LOADED	0x040000 /* whether all shdrs were read in */

struct _Elf {

	int		e_activations;	/* activation count */

	Elf_Arhdr	*e_arhdr;	/* header for archive members */

	unsigned int	e_byteorder;	/* ELFDATA* */

	int		e_class;	/* ELFCLASS*  */

	Elf_Cmd		e_cmd;		/* ELF_C_* used at creation time */

	int		e_fd;		/* associated file descriptor */

	unsigned int	e_flags;	/* ELF_F_*, LIBELF_F_* flags */

	Elf_Kind	e_kind;		/* ELF_K_* */

	Elf		*e_parent; 	/* non-NULL for archive members */

	char	 	*e_rawfile;	/* uninterpreted bytes */

	size_t		e_rawsize;	/* size of uninterpreted bytes */

	unsigned int	e_version;	/* file version */

	union {

		struct {		/* ar(1) archives */

			off_t	e_next;	/* set by elf_rand()/elf_next() */

			int	e_nchildren;

			char	*e_rawstrtab;	/* file name strings */

			size_t	e_rawstrtabsz;

			char	*e_rawsymtab;	/* symbol table */

			size_t	e_rawsymtabsz;

			Elf_Arsym *e_symtab;

			size_t	e_symtabsz;

		} e_ar;

		struct {		/* regular ELF files */

			union {

				Elf32_Ehdr *e_ehdr32;

				Elf64_Ehdr *e_ehdr64;

			} e_ehdr;

			union {

				Elf32_Phdr *e_phdr32;

				Elf64_Phdr *e_phdr64;

			} e_phdr;

			STAILQ_HEAD(, _Elf_Scn)	e_scn;	/* section list */

			size_t	e_nphdr;	/* number of Phdr entries */

			size_t	e_nscn;		/* number of sections */

			size_t	e_strndx;	/* string table section index */

		} e_elf;

	} e_u;

};

struct _Elf_Scn {

	union {

		Elf32_Shdr	s_shdr32;

		Elf64_Shdr	s_shdr64;

	} s_shdr;

	STAILQ_HEAD(, _Elf_Data) s_data;	/* list of Elf_Data descriptors */

	STAILQ_HEAD(, _Elf_Data) s_rawdata;	/* raw data for this section */

	STAILQ_ENTRY(_Elf_Scn) s_next;

	struct _Elf	*s_elf;		/* parent ELF descriptor */

	unsigned int	s_flags;	/* flags for the section as a whole */

	size_t		s_ndx;		/* index# for this section */

	uint64_t	s_offset;	/* managed by elf_update() */

	uint64_t	s_rawoff;	/* original offset in the file */

	uint64_t	s_size;		/* managed by elf_update() */

};

enum {

	ELF_TOFILE,

	ELF_TOMEMORY

};

#define	LIBELF_COPY_U32(DST,SRC,NAME)	do {		\

		if ((SRC)->NAME > UINT_MAX) {		\

			LIBELF_SET_ERROR(RANGE, 0);	\

			return (0);			\

		}					\

		(DST)->NAME = (SRC)->NAME;		\

	} while (0)

#define	LIBELF_COPY_S32(DST,SRC,NAME)	do {		\

		if ((SRC)->NAME > INT_MAX ||		\

		    (SRC)->NAME < INT_MIN) {		\

			LIBELF_SET_ERROR(RANGE, 0);	\

			return (0);			\

		}					\

		(DST)->NAME = (SRC)->NAME;		\

	} while (0)

/*

 * Prototypes

 */

Elf_Data *_libelf_allocate_data(Elf_Scn *_s);

Elf	*_libelf_allocate_elf(void);

Elf_Scn	*_libelf_allocate_scn(Elf *_e, size_t _ndx);

Elf_Arhdr *_libelf_ar_gethdr(Elf *_e);

Elf	*_libelf_ar_open(Elf *_e);

Elf	*_libelf_ar_open_member(int _fd, Elf_Cmd _c, Elf *_ar);

int	_libelf_ar_get_member(char *_s, size_t _sz, int _base, size_t *_ret);

char	*_libelf_ar_get_string(const char *_buf, size_t _sz, int _rawname);

char	*_libelf_ar_get_name(char *_buf, size_t _sz, Elf *_e);

int	_libelf_ar_get_number(char *_buf, size_t _sz, int _base, size_t *_ret);

Elf_Arsym *_libelf_ar_process_symtab(Elf *_ar, size_t *_dst);

unsigned long _libelf_checksum(Elf *_e, int _elfclass);

void	*_libelf_ehdr(Elf *_e, int _elfclass, int _allocate);

int	_libelf_falign(Elf_Type _t, int _elfclass);

size_t	_libelf_fsize(Elf_Type _t, int _elfclass, unsigned int _version,

    size_t count);

int	(*_libelf_get_translator(Elf_Type _t, int _direction, int _elfclass))

	    (char *_dst, size_t dsz, char *_src, size_t _cnt, int _byteswap);

void	*_libelf_getphdr(Elf *_e, int _elfclass);

void	*_libelf_getshdr(Elf_Scn *_scn, int _elfclass);

void	_libelf_init_elf(Elf *_e, Elf_Kind _kind);

int	_libelf_load_scn(Elf *e, void *ehdr);

int	_libelf_malign(Elf_Type _t, int _elfclass);

size_t	_libelf_msize(Elf_Type _t, int _elfclass, unsigned int _version);

void	*_libelf_newphdr(Elf *_e, int _elfclass, size_t _count);

Elf_Data *_libelf_release_data(Elf_Data *_d);

Elf	*_libelf_release_elf(Elf *_e);

Elf_Scn	*_libelf_release_scn(Elf_Scn *_s);

int	_libelf_setphnum(Elf *_e, void *_eh, int _elfclass, size_t _phnum);

int	_libelf_setshnum(Elf *_e, void *_eh, int _elfclass, size_t _shnum);

int	_libelf_setshstrndx(Elf *_e, void *_eh, int _elfclass,

    size_t _shstrndx);

Elf_Data *_libelf_xlate(Elf_Data *_d, const Elf_Data *_s,

    unsigned int _encoding, int _elfclass, int _direction);

int	_libelf_xlate_shtype(uint32_t _sht);

#endif	/* __LIBELF_H_ */

.\" Copyright (c) 2006,2007 Joseph Koshy.  All rights reserved.

.\"

.\" Redistribution and use in source and binary forms, with or without

.\" modification, are permitted provided that the following conditions

.\" are met:

.\" 1. Redistributions of source code must retain the above copyright

.\"    notice, this list of conditions and the following disclaimer.

.\" 2. Redistributions in binary form must reproduce the above copyright

.\"    notice, this list of conditions and the following disclaimer in the

.\"    documentation and/or other materials provided with the distribution.

.\"

.\" This software is provided by Joseph Koshy ``as is'' and

.\" any express or implied warranties, including, but not limited to, the

.\" implied warranties of merchantability and fitness for a particular purpose

.\" are disclaimed.  in no event shall Joseph Koshy be liable

.\" for any direct, indirect, incidental, special, exemplary, or consequential

.\" damages (including, but not limited to, procurement of substitute goods

.\" or services; loss of use, data, or profits; or business interruption)

.\" however caused and on any theory of liability, whether in contract, strict

.\" liability, or tort (including negligence or otherwise) arising in any way

.\" out of the use of this software, even if advised of the possibility of

.\" such damage.

.\"

.\" $FreeBSD: head/lib/libelf/elf.3 236438 2012-06-02 08:47:26Z joel $

.\"

.Dd October 21, 2007

.Dt ELF 3

.Os

.Sh NAME

.Nm elf

.Nd API for manipulating ELF objects

.Sh LIBRARY

.Lb libelf

.Sh SYNOPSIS

.In libelf.h

.Sh DESCRIPTION

The

.Lb libelf

provides functions that allow an application to read and manipulate

ELF object files, and to read

.Xr ar 1

archives.

The library allows the manipulation of ELF objects in a byte ordering

and word-size independent way, allowing an application to read and

create ELF objects for 32 and 64 bit architectures and for little-

and big-endian machines.

The library is capable of processing ELF objects that use extended

section numbering.

.Pp

This manual page serves to provide an overview of the functionality in

the ELF library.

Further information may found in the manual pages for individual

.Xr ELF 3

functions that comprise the library.

.Ss ELF Concepts

As described in

.Xr elf 5 ,

ELF files contain several data structures that are laid out in a

specific way.

ELF files begin with an

.Dq Executable Header ,

and may contain an optional

.Dq Program Header Table ,

and optional data in the form of ELF

.Dq sections .

A

.Dq Section Header Table

describes the content of the data in these sections.

.Pp

ELF objects have an associated

.Dq "ELF class"

which denotes the natural machine word size for the architecture

the object is associated with.

Objects for 32 bit architectures have an ELF class of

.Dv ELFCLASS32 .

Objects for 64 bit architectures have an ELF class of

.Dv ELFCLASS64 .

.Pp

ELF objects also have an associated

.Dq endianness

which denotes the endianness of the machine architecture associated

with the object.

This may be

.Dv ELFDATA2LSB

for little-endian architectures and

.Dv ELFDATA2MSB

for big-endian architectures.

.Pp

ELF objects are also associated with an API version number.

This version number determines the layout of the individual components

of an ELF file and the semantics associated with these.

.Ss Data Representation And Translation

The

.Xr ELF 3

library distinguishes between

.Dq native

representations of ELF data structures and their

.Dq file

representations.

.Pp

An application would work with ELF data in its

.Dq native

representation, i.e., using the native byteorder and alignment mandated

by the processor the application is running on.

The

.Dq file

representation of the same data could use a different byte ordering

and follow different constraints on object alignment than these native

constraints.

.Pp

Accordingly, the

.Xr ELF 3

library offers translation facilities

.Po

.Xr elf32_xlatetof 3 ,

.Xr elf32_xlatetom 3 ,

.Xr elf64_xlatetof 3

and

.Xr elf64_xlatetom 3

.Pc

to and from these

representations and also provides higher-level APIs that retrieve and store

data from the ELF object in a transparent manner.

.Ss Library Working Version

Conceptually, there are three version numbers associated with an

application using the ELF library to manipulate ELF objects:

.Bl -bullet -compact -offset indent

.It

The ELF version that the application was compiled against.

This version determines the ABI expected by the application.

.It

The ELF version of the ELF object being manipulated by the

application through the ELF library.

.It

The ELF version (or set of versions) supported by the ELF library itself.

.El

.Pp

In order to facilitate working with ELF objects of differing versions,

the ELF library requires the application to call the

.Fn elf_version

function before invoking many of its operations, in order to inform

the library of the application's desired working version.

.Pp

In the current implementation, all three versions have to be

.Dv EV_CURRENT .

.Ss Namespace use

The ELF library uses the following prefixes:

.Bl -tag -width "ELF_F_*"

.It elf_*

Used for class-independent functions.

.It elf32_*

Used for functions working with 32 bit ELF objects.

.It elf64_*

Used for functions working with 64 bit ELF objects.

.It Elf_*

Used for class-independent data types.

.It ELF_C_*

Used for command values used in a few functions.

These symbols are defined as members of the

.Vt Elf_Cmd

enumeration.

.It ELF_E_*

Used for error numbers.

.It ELF_F_*

Used for flags.

.It ELF_K_*

These constants define the kind of file associated with an ELF

descriptor.

See

.Xr elf_kind 3 .

The symbols are defined by the

.Vt Elf_Kind

enumeration.

.It ELF_T_*

These values are defined by the

.Vt Elf_Type

enumeration, and denote the types of ELF data structures

that can be present in an ELF object.

.El

.Ss Descriptors

Applications communicate with the library using descriptors.

These are:

.Bl -tag -width ".Vt Elf_Data"

.It Vt Elf

An

.Vt Elf

descriptor represents an ELF object or an

.Xr ar 1

archive.

It is allocated using one of the

.Fn elf_begin

or

.Fn elf_memory

functions.

An

.Vt Elf

descriptor can be used to read and write data to an ELF file.

An

.Vt Elf

descriptor can be associated with zero or more

.Vt Elf_Scn

section descriptors.

.Pp

Given an ELF descriptor, the application may retrieve the ELF

object's class-dependent

.Dq "Executable Header"

structures using the

.Fn elf32_getehdr

or

.Fn elf64_getehdr

functions.

A new Ehdr structure may be allocated using the

.Fn elf64_newehdr

or

.Fn elf64_newehdr

functions.

.Pp

The

.Dq "Program Header Table"

associated with an ELF descriptor may be allocated using the

.Fn elf32_getphdr

or

.Fn elf64_getphdr

functions.

A new program header table may be allocated or an existing table

resized using the

.Fn elf32_newphdr

or

.Fn elf64_newphdr

functions.

.Pp

The

.Vt Elf

structure is opaque and has no members visible to the

application.

.\" TODO describe the Elf_Arhdr and Elf_Arsym structures.

.It Vt Elf_Data

An

.Vt Elf_Data

data structure describes an individual chunk of a ELF file as

represented in memory.

It has the following application visible members:

.Bl -tag -width ".Vt unsigned int d_version" -compact

.It Vt "uint64_t d_align"

The in-file alignment of the data buffer within its containing ELF section.

This value must be a power of two.

.It Vt "uint64_t d_off"

The offset with the containing section where this descriptors data

would be placed.

This field will be computed by the library unless the application

requests full control of the ELF object's layout.

.It Vt "uint64_t d_size"

The number of bytes of data in this descriptor.

.It Vt "void *d_buf"

A pointer to data in memory.

.It Vt "Elf_Type d_type"

The ELF type (see below) of the data in this descriptor.

.It Vt "unsigned int d_version"

The operating version for the data in this buffer.

.El

.Pp

.Vt Elf_Data

descriptors are usually associated with

.Vt Elf_Scn

descriptors.

Existing data descriptors associated with an ELF section may be

structures are retrieved using the

.Fn elf_getdata

function.

The

.Fn elf_newdata

function may be used to attach new data descriptors to an ELF section.

.It Vt Elf_Scn

.Vt Elf_Scn

descriptors represent a section in an ELF object.

.Pp

They are retrieved using the

.Fn elf_getscn

function.

An application may iterate through the existing sections of an ELF

object using the

.Fn elf_nextscn

function.

New sections may be allocated using the

.Fn elf_newscn

function.

.Pp

The

.Vt Elf_Scn

descriptor is opaque and contains no application modifiable fields.

.El

.Ss Supported Elf Types

The following ELF datatypes are supported by the library.

.Pp

.Bl -tag -width ".Dv ELF_T_SYMINFO" -compact

.It Dv ELF_T_ADDR

Machine addresses.

.It Dv ELF_T_BYTE

Byte data.

The library will not attempt to translate byte data.

.It Dv ELF_T_CAP

Software and hardware capability records.

.It Dv ELF_T_DYN

Records used in a section of type

.Dv SHT_DYNAMIC .

.It Dv ELF_T_EHDR

ELF executable header.

.It Dv ELF_T_HALF

16-bit unsigned words.

.It Dv ELF_T_LWORD

64 bit unsigned words.

.It Dv ELF_T_MOVE

ELF Move records.

.\".It Dv ELF_T_MOVEP

.\" As yet unsupported.

.It Dv ELF_T_NOTE

ELF Note structures.

.It Dv ELF_T_OFF

File offsets.

.It Dv ELF_T_PHDR

ELF program header table entries.

.It Dv ELF_T_REL

ELF relocation entries.

.It Dv ELF_T_RELA

ELF relocation entries with addends.

.It Dv ELF_T_SHDR

ELF section header entries.

.It Dv ELF_T_SWORD

Signed 32-bit words.

.It Dv ELF_T_SXWORD

Signed 64-bit words.

.It Dv ELF_T_SYMINFO

ELF symbol information.

.It Dv ELF_T_SYM

ELF symbol table entries.

.It Dv ELF_T_VDEF

Symbol version definition records.

.It Dv ELF_T_VNEED

Symbol version requirement records.

.It Dv ELF_T_WORD

Unsigned 32-bit words.

.It Dv ELF_T_XWORD

Unsigned 64-bit words.

.El

.Pp

The symbol

.Dv ELF_T_NUM

denotes the number of Elf types known to the library.

.Pp

The following table shows the mapping between ELF section types

defined in

.Xr elf 5

and the types supported by the library.

.Bl -column ".Dv SHT_PREINIT_ARRAY" ".Dv ELF_T_SYMINFO"

.It Em Section Type Ta Em "Library Type" Ta Em Description

.It Dv SHT_DYNAMIC Ta Dv ELF_T_DYN Ta Xo

.Sq .dynamic

section entries.

.Xc

.It Dv SHT_DYNSYM Ta Dv ELF_T_SYM Ta Symbols for dynamic linking.

.It Dv SHT_FINI_ARRAY Ta Dv ELF_T_ADDR Ta Termination function pointers.

.It Dv SHT_GROUP Ta Dv ELF_T_WORD Ta Section group marker.

.It Dv SHT_HASH Ta Dv ELF_T_HASH Ta Symbol hashes.

.It Dv SHT_INIT_ARRAY Ta Dv ELF_T_ADDR Ta Initialization function pointers.

.It Dv SHT_NOBITS Ta Dv ELF_T_BYTE Ta Xo

Empty sections.

See

.Xr elf 5 .

.Xc

.It Dv SHT_NOTE Ta Dv ELF_T_NOTE Ta ELF note records.

.It Dv SHT_PREINIT_ARRAY Ta Dv ELF_T_ADDR Ta Pre-initialization function pointers.

.It Dv SHT_PROGBITS Ta Dv ELF_T_BYTE Ta Machine code.

.It Dv SHT_REL Ta Dv ELF_T_REL Ta ELF relocation records.

.It Dv SHT_RELA Ta Dv ELF_T_RELA Ta Relocation records with addends.

.It Dv SHT_STRTAB Ta Dv ELF_T_BYTE Ta String tables.

.It Dv SHT_SYMTAB Ta Dv ELF_T_SYM Ta Symbol tables.

.It Dv SHT_SYMTAB_SHNDX Ta Dv ELF_T_WORD Ta Used with extended section numbering.

.It Dv SHT_GNU_verdef Ta Dv ELF_T_VDEF Ta Symbol version definitions.

.It Dv SHT_GNU_verneed Ta Dv ELF_T_VNEED Ta Symbol versioning requirements.

.It Dv SHT_GNU_versym Ta Dv ELF_T_HALF Ta Version symbols.

.It Dv SHT_SUNW_move Ta Dv ELF_T_MOVE Ta ELF move records.

.It Dv SHT_SUNW_syminfo Ta Dv ELF_T_SYMINFO Ta Additional symbol flags.

.El

.Ss Functional Grouping

This section contains a brief overview of the available functionality

in the ELF library.

Each function listed here is described further in its own manual page.

.Bl -tag -width 2n

.It "Archive Access"

.Bl -tag -width 17n -compact

.It Fn elf_getarsym

Retrieve the archive symbol table.

.It Fn elf_getarhdr

Retrieve the archive header for an object.

.It Fn elf_getbase

Retrieve the offset of a member inside an archive.

.It Fn elf_next

Iterate through an

.Xr ar 1

archive.

.It Fn elf_rand

Random access inside an

.Xr ar 1

archive.

.El

.It "Data Structures"

.Bl -tag -width 17n -compact

.It Fn elf_getdata

Retrieve translated data for an ELF section.

.It Fn elf_getscn

Retrieve the section descriptor for a named section.

.It Fn elf_ndxscn

Retrieve the index for a section.

.It Fn elf_newdata

Add a new

.Vt Elf_Data

descriptor to an ELF section.

.It Fn elf_newscn

Add a new section descriptor to an ELF descriptor.

.It Fn elf_nextscn

Iterate through the sections in an ELF object.

.It Fn elf_rawdata

Retrieve untranslated data for an ELF sectino.

.It Fn elf_rawfile

Return a pointer to the untranslated file contents for an ELF object.

.It Fn elf32_getehdr , Fn elf64_getehdr

Retrieve the Executable Header in an ELF object.

.It Fn elf32_getphdr , Fn elf64_getphdr

Retrieve the Program Header Table in an ELF object.

.It Fn elf32_getshdr , Fn elf64_getshdr

Retrieve the ELF section header associated with an

.Vt Elf_Scn

descriptor.

.It Fn elf32_newehdr , Fn elf64_newehdr

Allocate an Executable Header in an ELF object.

.It Fn elf32_newphdr , Fn elf64_newphdr

Allocate or resize the Program Header Table in an ELF object.

.El

.It "Data Translation"

.Bl -tag -width 17n -compact

.It Fn elf32_xlatetof , Fn elf64_xlatetof

Translate an ELF data structure from its native representation to its

file representation.

.It Fn elf32_xlatetom , Fn elf64_xlatetom

Translate an ELF data structure from its file representation to a

native representation.

.El

.It "Error Reporting"

.Bl -tag -width 17n -compact

.It Fn elf_errno

Retrieve the current error.

.It Fn elf_errmsg

Retrieve a human readable description of the current error.

.El

.It "Initialization"

.Bl -tag -width 17n -compact

.It Fn elf_begin

Opens an

.Xr ar 1

archive or ELF object given a file descriptor.

.It Fn elf_end

Close an ELF descriptor and release all its resources.

.It Fn elf_memory

Opens an

.Xr ar 1

archive or ELF object present in a memory area.

.It Fn elf_version

Sets the operating version.

.El

.It "IO Control"

.Bl -tag -width 17n -compact

.It Fn elf_cntl

Manage the association between and ELF descriptor and its underlying file.

.It Fn elf_flagdata

Mark an

.Vt Elf_Data

descriptor as dirty.

.It Fn elf_flagehdr

Mark the ELF Executable Header in an ELF descriptor as dirty.

.It Fn elf_flagphdr

Mark the ELF Program Header Table in an ELF descriptor as dirty.

.It Fn elf_flagscn

Mark an

.Vt Elf_Scn

descriptor as dirty.

.It Fn elf_flagshdr

Mark an ELF Section Header as dirty.

.It Fn elf_setshstrndx

Set the index of the section name string table for the ELF object.

.It Fn elf_update

Recompute ELF object layout and optionally write the modified object

back to the underlying file.

.El

.It "Queries"

.Bl -tag -width 17n -compact

.It Fn elf32_checksum , Fn elf64_checkum

Compute checksum of an ELF object.

.It Fn elf_getident

Retrieve the identification bytes for an ELF object.

.It Fn elf_getshnum

Retrieve the number of sections in an ELF object.

.It Fn elf_getshstrndx

Retrieve the section index of the section name string table in

an ELF object.

.It Fn elf_hash

Compute the ELF hash value of a string.

.It Fn elf_kind

Query the kind of object associated with an ELF descriptor.

.It Fn elf32_fsize , Fn elf64_fsize

Return the size of the file representation of an ELF type.

.El

.El

.Ss Controlling ELF Object Layout

In the usual mode of operation, library will compute section

offsets and alignments based on the contents of an ELF descriptor's

sections without need for further intervention by the

application.

.Pp

However, if the application wishes to take complete charge of the

layout of the ELF file, it may set the

.Dv ELF_F_LAYOUT

flag on an ELF descriptor using

.Xr elf_flagelf 3 ,

following which the library will use the data offsets and alignments

specified by the application when laying out the file.

Application control of file layout is described further in the

.Xr elf_update 3

manual page.

.Pp

Gaps in between sections will be filled with the fill character

set by function

.Fn elf_fill .

.Ss Error Handling

In case an error is encountered, these library functions set an

internal error number and signal the presence of the error by

returning an special return value.

The application can check the

current error number by calling

.Xr elf_errno 3 .

A human readable description of the recorded error is available by

calling

.Xr elf_errmsg 3 .

.Ss Memory Management Rules

The library keeps track of all

.Vt Elf_Scn

and

.Vt Elf_Data

descriptors associated with an ELF descriptor and recovers them

when the descriptor is closed using

.Xr elf_end 3 .

Thus the application must not call

.Xr free 3

on data structures allocated by the ELF library.

.Pp

Conversely the library will not

free data that it has not allocated.

As an example, an application may call

.Xr elf_newdata 3

to allocate a new

.Vt Elf_Data

descriptor and can set the

.Va d_off

member of the descriptor to point to a region of memory allocated

using

.Xr malloc 3 .

It is the applications responsibility to free this area, though the

library will reclaim the space used by the

.Vt Elf_Data

descriptor itself.

.Sh SEE ALSO

.Xr gelf 3 ,

.Xr elf 5

.Sh HISTORY

The original ELF(3) API was developed for Unix System V.

The current implementation of the ELF(3) API appeared in

.Fx 7.0 .

.Sh AUTHORS

The ELF library was written by

.An "Joseph Koshy"

.Aq jkoshy@FreeBSD.org .

.\" Copyright (c) 2006 Joseph Koshy.  All rights reserved.

.\"

.\" Redistribution and use in source and binary forms, with or without

.\" modification, are permitted provided that the following conditions

.\" are met:

.\" 1. Redistributions of source code must retain the above copyright

.\"    notice, this list of conditions and the following disclaimer.

.\" 2. Redistributions in binary form must reproduce the above copyright

.\"    notice, this list of conditions and the following disclaimer in the

.\"    documentation and/or other materials provided with the distribution.

.\"

.\" This software is provided by Joseph Koshy ``as is'' and

.\" any express or implied warranties, including, but not limited to, the

.\" implied warranties of merchantability and fitness for a particular purpose

.\" are disclaimed.  in no event shall Joseph Koshy be liable

.\" for any direct, indirect, incidental, special, exemplary, or consequential

.\" damages (including, but not limited to, procurement of substitute goods

.\" or services; loss of use, data, or profits; or business interruption)

.\" however caused and on any theory of liability, whether in contract, strict

.\" liability, or tort (including negligence or otherwise) arising in any way

.\" out of the use of this software, even if advised of the possibility of

.\" such damage.

.\"

.\" $FreeBSD: head/lib/libelf/elf_begin.3 236626 2012-06-05 18:19:52Z joel $

.\"

.Dd June 20, 2010

.Dt ELF_BEGIN 3

.Os

.Sh NAME

.Nm elf_begin

.Nd open an ELF file or ar(1) archive

.Sh LIBRARY

.Lb libelf

.Sh SYNOPSIS

.In libelf.h

.Ft "Elf *"

.Fn elf_begin "int fd" "Elf_Cmd cmd" "Elf *elf"

.Sh DESCRIPTION

Function

.Fn elf_begin

is used to open ELF files and

.Xr ar 1

archives for further processing by other APIs in the

.Xr elf 3

library.

It is also used to access individual ELF members of an

.Xr ar 1

archive in combination with the

.Xr elf_next 3

and

.Xr elf_rand 3

APIs.

.Pp

Argument

.Ar fd

is an open file descriptor returned from an

.Xr open 2

system call.

Function

.Fn elf_begin

uses argument

.Ar fd

for reading or writing depending on the value of argument

.Ar cmd .

Argument

.Ar elf

is primarily used for iterating through archives.

.Pp

The argument

.Ar cmd

can have the following values:

.Bl -tag -width "ELF_C_WRITE"

.It ELF_C_NULL

Causes

.Fn elf_begin

to return NULL.

Arguments

.Ar fd

and

.Ar elf

are ignored, and no additional error is signalled.

.It ELF_C_READ

This value is to be when the application wishes to examine (but not

modify) the contents of the file specified by argument

.Ar fd .

It can be used for both

.Xr ar 1

archives and for regular ELF files.

.Pp

Argument

.Ar fd

should have been opened for reading.

If argument

.Ar elf

is NULL, the library will allocate a new ELF descriptor for

the file being processed.

If argument

.Ar elf

is not NULL, and references a regular ELF file previously opened with

.Fn elf_begin ,

then the activation count for

.Ar elf

is incremented.

If argument

.Ar elf

is not NULL, and references a descriptor for an

.Xr ar 1

archive opened earlier with

.Fn elf_begin ,

a descriptor for an element in the archive is returned as

described in the section

.Sx "Processing ar(1) archives"

below.

.It Dv ELF_C_RDWR

The command is used to prepare an ELF file for reading and writing.

It is not supported for archives.

.Pp

Argument

.Ar fd

should have been opened for reading and writing.

If argument

.Ar elf

is NULL, the library will allocate a new ELF descriptor for

the file being processed.

If the argument

.Ar elf

is non-null, it should point to a descriptor previously

allocated with

.Fn elf_begin

with the same values for arguments

.Ar fd

and

.Ar cmd ;

in this case the library will increment the activation count for descriptor

.Ar elf

and return the same descriptor.

Changes to the in-memory image of the ELF file are written back to

disk using the

.Xr elf_update 3

function.

.Pp

This command is not valid for

.Xr ar 1

archives.

.It Dv ELF_C_WRITE

This command is used when the application wishes to create a new ELF

file.

Argument

.Ar fd

should have been opened for writing.

Argument

.Ar elf

is ignored, and the previous contents of file referenced by

argument

.Ar fd

are overwritten.

.El

.Ss Processing ar(1) archives

An

.Xr ar 1

archive may be opened in read mode (with argument

.Ar cmd

set to

.Dv ELF_C_READ )

using

.Fn elf_begin

or

.Fn elf_memory .

The returned ELF descriptor can be passed into to

subsequent calls to

.Fn elf_begin

to access individual members of the archive.

.Pp

Random access within an opened archive is possible using

the

.Xr elf_next 3

and

.Xr elf_rand 3

functions.

.Pp

The symbol table of the archive may be retrieved

using

.Xr elf_getarsym 3 .

.Sh RETURN VALUES

The function returns a pointer to a ELF descriptor if successful, or NULL

if an error occurred.

.Sh EXAMPLES

To iterate through the members of an

.Xr ar 1

archive, use:

.Bd -literal -offset indent

Elf_Cmd c;

Elf *ar_e, *elf_e;

\&...

c = ELF_C_READ;

if ((ar_e = elf_begin(fd, c, (Elf *) 0)) == 0) {

	\&... handle error in opening the archive ...

}

while ((elf_e = elf_begin(fd, c, ar_e)) != 0) {

	\&... process member referenced by elf_e here ...

	c = elf_next(elf_e);

	elf_end(elf_e);

}

.Ed

.Pp

To create a new ELF file, use:

.Bd -literal -offset indent

int fd;

Elf *e;

\&...

if ((fd = open("filename", O_RDWR|O_TRUNC|O_CREAT, 0666)) < 0) {

	\&... handle the error from open(2) ...

}

if ((e = elf_begin(fd, ELF_C_WRITE, (Elf *) 0)) == 0) {

	\&... handle the error from elf_begin() ...

}

\&... create the ELF image using other elf(3) APIs ...

elf_update(e, ELF_C_WRITE);

elf_end(e);

.Ed

.Sh ERRORS

Function

.Fn elf_begin

can fail with the following errors:

.Bl -tag -width "[ELF_E_RESOURCE]"

.It Bq Er ELF_E_ARCHIVE

The archive denoted by argument

.Ar elf

could not be parsed.

.It Bq Er ELF_E_ARGUMENT

An unrecognized value was specified in argument

.Ar cmd .

.It Bq Er ELF_E_ARGUMENT

A non-null value for argument

.Ar elf

was specified when

.Ar cmd

was set to

.Dv ELF_C_RDWR .

.It Bq Er ELF_E_ARGUMENT

The value of argument

.Ar fd

differs from the one the ELF descriptor

.Ar elf

was created with.

.It Bq Er ELF_E_ARGUMENT

Argument

.Ar cmd

differs from the value specified when ELF descriptor

.Ar elf

was created.

.It Bq Er ELF_E_ARGUMENT

An

.Xr ar 1

archive was opened with

.Ar cmd

set to

.Dv ELF_C_RDWR .

.It Bq Er ELF_E_IO

Function

.Fn elf_begin

was unable to truncate a file opened for writing using

.Dv ELF_C_WRITE .

.It Bq Er ELF_E_RESOURCE

An out of memory condition was encountered.

.It Bq Er ELF_E_SEQUENCE

Function

.Fn elf_begin

was called before a working version was established with

.Xr elf_version 3 .

.El

.Sh SEE ALSO

.Xr elf 3 ,

.Xr elf_end 3 ,

.Xr elf_errno 3 ,

.Xr elf_memory 3 ,

.Xr elf_next 3 ,

.Xr elf_rand 3 ,

.Xr elf_update 3 ,

.Xr gelf 3

/*-

 * Copyright (c) 2006 Joseph Koshy

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <sys/cdefs.h>

__FBSDID("$FreeBSD: releng/9.1/lib/libelf/elf_begin.c 210351 2010-07-21 13:18:57Z kaiw $");

#include <sys/types.h>

#include <sys/errno.h>

#include <sys/mman.h>

#include <sys/stat.h>

#include <ar.h>

#include <ctype.h>

#include <libelf.h>

#include <unistd.h>

#include "_libelf.h"

static Elf *

_libelf_open_object(int fd, Elf_Cmd c)

{

	Elf *e;

	void *m;

	struct stat sb;

	/*

	 * 'Raw' files are always mapped with 'PROT_READ'.  At

	 * elf_update(3) time for files opened with ELF_C_RDWR the

	 * mapping is unmapped, file data is written to using write(2)

	 * and then the raw data is immediately mapped back in.

	 */

	if (fstat(fd, &sb) < 0) {

		LIBELF_SET_ERROR(IO, errno);

		return (NULL);

	}

	m = NULL;

	if ((m = mmap(NULL, (size_t) sb.st_size, PROT_READ, MAP_PRIVATE, fd,

	    (off_t) 0)) == MAP_FAILED) {

		LIBELF_SET_ERROR(IO, errno);

		return (NULL);

	}

	if ((e = elf_memory(m, (size_t) sb.st_size)) == NULL) {

		(void) munmap(m, (size_t) sb.st_size);

		return (NULL);

	}

	e->e_flags |= LIBELF_F_MMAP;

	e->e_fd = fd;

	e->e_cmd = c;

	if (c == ELF_C_RDWR && e->e_kind == ELF_K_AR) {

		(void) elf_end(e);

		LIBELF_SET_ERROR(ARGUMENT, 0);

		return (NULL);

	}

	return (e);

}

Elf *

elf_begin(int fd, Elf_Cmd c, Elf *a)

{

	Elf *e;

	e = NULL;

	if (LIBELF_PRIVATE(version) == EV_NONE) {

		LIBELF_SET_ERROR(SEQUENCE, 0);

		return (NULL);

	}

	switch (c) {

	case ELF_C_NULL:

		return (NULL);

	case ELF_C_WRITE:

		if (a != NULL) { /* not allowed for ar(1) archives. */

			LIBELF_SET_ERROR(ARGUMENT, 0);

			return (NULL);

		}

		/*

		 * Check writeability of `fd' immediately and fail if

		 * not writeable.

		 */

		if (ftruncate(fd, (off_t) 0) < 0) {

			LIBELF_SET_ERROR(IO, errno);

			return (NULL);

		}

		if ((e = _libelf_allocate_elf()) != NULL) {

			_libelf_init_elf(e, ELF_K_ELF);

			e->e_byteorder = LIBELF_PRIVATE(byteorder);

			e->e_fd = fd;

			e->e_cmd = c;

		}

		return (e);

	case ELF_C_RDWR:

		if (a != NULL) { /* not allowed for ar(1) archives. */

			LIBELF_SET_ERROR(ARGUMENT, 0);

			return (NULL);

		}

		/*FALLTHROUGH*/

	case ELF_C_READ:

		/*

		 * Descriptor `a' could be for a regular ELF file, or

		 * for an ar(1) archive.  If descriptor `a' was opened

		 * using a valid file descriptor, we need to check if

		 * the passed in `fd' value matches the original one.

		 */

		if (a &&

		    ((a->e_fd != -1 && a->e_fd != fd) || c != a->e_cmd)) {

			LIBELF_SET_ERROR(ARGUMENT, 0);

			return (NULL);

		}

		break;

	default:

		LIBELF_SET_ERROR(ARGUMENT, 0);

		return (NULL);

	}

	if (a == NULL)

		e = _libelf_open_object(fd, c);

	else if (a->e_kind == ELF_K_AR)

		e = _libelf_ar_open_member(a->e_fd, c, a);

	else

		(e = a)->e_activations++;

	return (e);

}

.\" Copyright (c) 2006 Joseph Koshy.  All rights reserved.

.\"

.\" Redistribution and use in source and binary forms, with or without

.\" modification, are permitted provided that the following conditions

.\" are met:

.\" 1. Redistributions of source code must retain the above copyright

.\"    notice, this list of conditions and the following disclaimer.

.\" 2. Redistributions in binary form must reproduce the above copyright

.\"    notice, this list of conditions and the following disclaimer in the

.\"    documentation and/or other materials provided with the distribution.

.\"

.\" This software is provided by Joseph Koshy ``as is'' and

.\" any express or implied warranties, including, but not limited to, the

.\" implied warranties of merchantability and fitness for a particular purpose

.\" are disclaimed.  in no event shall Joseph Koshy be liable

.\" for any direct, indirect, incidental, special, exemplary, or consequential

.\" damages (including, but not limited to, procurement of substitute goods

.\" or services; loss of use, data, or profits; or business interruption)

.\" however caused and on any theory of liability, whether in contract, strict

.\" liability, or tort (including negligence or otherwise) arising in any way

.\" out of the use of this software, even if advised of the possibility of

.\" such damage.

.\"

.\" $FreeBSD: releng/9.1/lib/libelf/elf_cntl.3 219210 2011-03-02 21:59:53Z uqs $

.\"

.Dd August 9, 2006

.Dt ELF_CNTL 3

.Os

.Sh NAME

.Nm elf_cntl

.Nd control an elf file descriptor

.Sh LIBRARY

.Lb libelf

.Sh SYNOPSIS

.In libelf.h

.Ft int

.Fn elf_cntl "Elf *elf" "Elf_Cmd cmd"

.Sh DESCRIPTION

Function

.Fn elf_cntl

controls the ELF library's subsequent use of the file descriptor

used to create ELF descriptor

.Ar elf .

.Pp

Argument

.Ar cmd

informs the library of the action to be taken:

.Bl -tag -width "ELF_C_FDDONE"

.It Dv ELF_C_FDDONE

This value instructs the ELF library not to perform any further

I/O on the file descriptor associated with argument

.Ar elf .

For ELF descriptors opened with mode

.Ar ELF_C_WRITE

or

.Ar ELF_C_RDWR

subsequent

.Fn elf_update

operations on the descriptor will fail.

.It Dv ELF_C_FDREAD

This value instructs the ELF library to read in all necessary

data associated with ELF descriptor

.Ar elf

into memory so that the underlying file descriptor can be

safely closed with command

.Dv ELF_C_FDDONE .

.El

.Pp

Argument

.Ar elf

must be an ELF descriptor associated with a file system object

(e.g., an

.Xr ar 1

archive, an ELF file, or other data file).

.Sh IMPLEMENTATION NOTES

Due to use of

.Xr mmap 2

internally, this function is a no-op for ELF objects opened in

.Dv ELF_C_READ

mode.

.Sh RETURN VALUES

Function

.Fn elf_cntl

returns 0 on success, or -1 if an error was detected.

.Sh ERRORS

.Bl -tag -width "[ELF_E_RESOURCE]"

.It Bq Er ELF_E_ARCHIVE

Argument

.Ar elf

is a descriptor for an archive member.

.It Bq Er ELF_E_ARGUMENT

Argument

.Ar elf

was NULL.

.It Bq Er ELF_E_ARGUMENT

Argument

.Ar cmd

was not recognized.

.It Bq Er ELF_E_MODE

An

.Dv ELF_C_FDREAD

operation was requested on an ELF descriptor opened

for writing.

.El

.Sh SEE ALSO

.Xr elf 3 ,

.Xr elf_begin 3 ,

.Xr elf_end 3 ,

.Xr elf_next 3 ,

.Xr elf_update 3 ,

.Xr gelf 3

/*-

 * Copyright (c) 2006 Joseph Koshy

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <sys/cdefs.h>

__FBSDID("$FreeBSD: releng/9.1/lib/libelf/elf_cntl.c 164190 2006-11-11 17:16:35Z jkoshy $");

#include <libelf.h>

#include "_libelf.h"

int

elf_cntl(Elf *e, Elf_Cmd c)

{

	if (e == NULL ||

	    (c != ELF_C_FDDONE && c != ELF_C_FDREAD)) {

		LIBELF_SET_ERROR(ARGUMENT, 0);

		return (-1);

	}