152 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			Groff
		
	
	
	
	
	
			
		
		
	
	
			152 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			Groff
		
	
	
	
	
	
.\" Copyright (c) 2006-2008 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.
 | 
						|
.\"
 | 
						|
.\" $Id$
 | 
						|
.\"
 | 
						|
.Dd October 22, 2007
 | 
						|
.Os
 | 
						|
.Dt ELF_GETSCN 3
 | 
						|
.Sh NAME
 | 
						|
.Nm elf_getscn ,
 | 
						|
.Nm elf_ndxscn ,
 | 
						|
.Nm elf_newscn ,
 | 
						|
.Nm elf_nextscn
 | 
						|
.Nd get/allocate section information for an ELF object
 | 
						|
.Sh LIBRARY
 | 
						|
.Lb libelf
 | 
						|
.Sh SYNOPSIS
 | 
						|
.In libelf.h
 | 
						|
.Ft "Elf_Scn *"
 | 
						|
.Fn elf_getscn "Elf *elf" "size_t index"
 | 
						|
.Ft size_t
 | 
						|
.Fn elf_ndxscn "Elf_Scn *scn"
 | 
						|
.Ft "Elf_Scn *"
 | 
						|
.Fn elf_newscn "Elf *elf"
 | 
						|
.Ft "Elf_Scn *"
 | 
						|
.Fn elf_nextscn "Elf *elf" "Elf_Scn *scn"
 | 
						|
.Sh DESCRIPTION
 | 
						|
These functions are used to iterate through the sections associated
 | 
						|
with an ELF descriptor.
 | 
						|
.Pp
 | 
						|
Function
 | 
						|
.Fn elf_getscn
 | 
						|
will return a section descriptor for the section at index
 | 
						|
.Ar index
 | 
						|
in the object denoted by ELF descriptor
 | 
						|
.Ar elf .
 | 
						|
An error will be signalled if the specified section does not
 | 
						|
exist.
 | 
						|
.Pp
 | 
						|
Function
 | 
						|
.Fn elf_ndxscn
 | 
						|
returns the section table index associated with section descriptor
 | 
						|
.Ar scn .
 | 
						|
.Pp
 | 
						|
Function
 | 
						|
.Fn elf_newscn
 | 
						|
creates a new section and appends it to the list of sections
 | 
						|
associated with descriptor
 | 
						|
.Ar elf .
 | 
						|
The library will automatically increment the
 | 
						|
.Va e_shnum
 | 
						|
field of the ELF header associated with descriptor
 | 
						|
.Ar elf ,
 | 
						|
and will set the
 | 
						|
.Dv ELF_F_DIRTY
 | 
						|
flag on the returned section descriptor.
 | 
						|
For ELF descriptors opened for writing, the ELF library will
 | 
						|
automatically create an empty section at index zero
 | 
						|
.Dv ( SHN_UNDEF )
 | 
						|
on the first call to
 | 
						|
.Fn elf_newscn .
 | 
						|
.Pp
 | 
						|
Function
 | 
						|
.Fn elf_nextscn
 | 
						|
takes a section descriptor
 | 
						|
.Ar scn
 | 
						|
and returns a pointer to the section descriptor at the next higher
 | 
						|
index.
 | 
						|
Argument
 | 
						|
.Ar scn
 | 
						|
is allowed to be NULL, in which case this function will return a
 | 
						|
pointer to the section descriptor at index 1.
 | 
						|
If no further sections are present, function
 | 
						|
.Fn elf_nextscn
 | 
						|
will return a NULL pointer.
 | 
						|
.Sh RETURN VALUES
 | 
						|
Functions
 | 
						|
.Fn elf_getscn ,
 | 
						|
.Fn elf_newscn
 | 
						|
and
 | 
						|
.Fn elf_nextscn
 | 
						|
return a valid pointer to a section descriptor if successful, or
 | 
						|
NULL if an error occurs.
 | 
						|
.Pp
 | 
						|
Function
 | 
						|
.Fn elf_ndxscn
 | 
						|
returns a valid section table index if successful, or
 | 
						|
.Dv SHN_UNDEF
 | 
						|
if an error occurs.
 | 
						|
.Sh ERRORS
 | 
						|
These functions may fail with the following errors:
 | 
						|
.Bl -tag -width "[ELF_E_RESOURCE]"
 | 
						|
.It Bq Er ELF_E_ARGUMENT
 | 
						|
Arguments
 | 
						|
.Ar elf
 | 
						|
or
 | 
						|
.Ar scn
 | 
						|
were NULL.
 | 
						|
.It Bq Er ELF_E_ARGUMENT
 | 
						|
Argument
 | 
						|
.Ar index
 | 
						|
exceeded the current number of sections in the ELF object.
 | 
						|
.It Bq Er ELF_E_ARGUMENT
 | 
						|
Argument
 | 
						|
.Ar elf
 | 
						|
was not a descriptor for an ELF file.
 | 
						|
.It Bq Er ELF_E_ARGUMENT
 | 
						|
Section descriptor
 | 
						|
.Ar scn
 | 
						|
was not associated with ELF descriptor
 | 
						|
.Ar elf .
 | 
						|
.It Bq Er ELF_E_CLASS
 | 
						|
Descriptor
 | 
						|
.Ar elf
 | 
						|
was of an unknown ELF class.
 | 
						|
.It Bq Er ELF_E_SECTION
 | 
						|
Argument
 | 
						|
.Ar elf
 | 
						|
specified extended section numbering in the ELF header with the section header at
 | 
						|
index
 | 
						|
.Dv SHN_UNDEF
 | 
						|
not being of type
 | 
						|
.Dv SHT_NULL .
 | 
						|
.El
 | 
						|
.Sh SEE ALSO
 | 
						|
.Xr elf 3 ,
 | 
						|
.Xr elf_flagdata 3 ,
 | 
						|
.Xr elf_flagscn 3 ,
 | 
						|
.Xr elf_getdata 3 ,
 | 
						|
.Xr elf_getshdr 3 ,
 | 
						|
.Xr gelf 3
 |