2007-10-22 03:38:43 +00:00
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.\" Copyright (c) 2006,2007 Joseph Koshy. All rights reserved.
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2006-11-11 17:16:35 +00:00
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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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.\" $FreeBSD$
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.\"
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2007-10-22 03:38:43 +00:00
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.Dd October 22, 2007
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2006-11-13 09:46:16 +00:00
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.Dt ELF_GETSCN 3
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2010-04-14 19:08:06 +00:00
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.Os
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2006-11-11 17:16:35 +00:00
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.Sh NAME
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.Nm elf_getscn ,
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.Nm elf_ndxscn ,
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.Nm elf_newscn ,
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.Nm elf_nextscn
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.Nd get/allocate section information for an ELF object
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.Sh LIBRARY
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.Lb libelf
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.Sh SYNOPSIS
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.In libelf.h
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.Ft "Elf_Scn *"
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.Fn elf_getscn "Elf *elf" "size_t index"
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.Ft size_t
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.Fn elf_ndxscn "Elf_Scn *scn"
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.Ft "Elf_Scn *"
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.Fn elf_newscn "Elf *elf"
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.Ft "Elf_Scn *"
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.Fn elf_nextscn "Elf *elf" "Elf_Scn *scn"
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.Sh DESCRIPTION
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These functions are used to iterate through the sections associated
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with an ELF descriptor.
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.Pp
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Function
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.Fn elf_getscn
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will return a section descriptor for the section at index
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.Ar index
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in the object denoted by ELF descriptor
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.Ar elf .
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An error will be signalled if the specified section does not
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exist.
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.Pp
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Function
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.Fn elf_ndxscn
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returns the section table index associated with section descriptor
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.Ar scn .
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.Pp
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Function
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.Fn elf_newscn
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creates a new section and appends it to the list of sections
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associated with descriptor
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.Ar elf .
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The library will automatically increment the
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.Va e_shnum
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field of the ELF header associated with descriptor
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.Ar elf ,
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and will set the
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.Dv ELF_F_DIRTY
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2007-10-22 03:38:43 +00:00
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flag on the returned section descriptor.
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2006-11-11 17:16:35 +00:00
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For ELF descriptors opened for writing, the ELF library will
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automatically create an empty section at index zero
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.Dv ( SHN_UNDEF )
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on the first call to
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.Fn elf_newscn .
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.Pp
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Function
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.Fn elf_nextscn
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takes a section descriptor
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.Ar scn
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and returns a pointer to the section descriptor at the next higher
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index.
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Argument
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.Ar scn
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is allowed to be NULL, in which case this function will return a
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pointer to the section descriptor at index 1.
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If no further sections are present, function
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.Fn elf_nextscn
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will return a NULL pointer.
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.Sh RETURN VALUES
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Functions
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.Fn elf_getscn ,
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.Fn elf_newscn
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and
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.Fn elf_nextscn
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return a valid pointer to a section descriptor if successful, or
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NULL if an error occurs.
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.Pp
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Function
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.Fn elf_ndxscn
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returns a valid section table index if successful, or
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.Dv SHN_UNDEF
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if an error occurs.
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.Sh ERRORS
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These functions may fail with the following errors:
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.Bl -tag -width "[ELF_E_RESOURCE]"
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.It Bq Er ELF_E_ARGUMENT
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Arguments
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.Ar elf
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or
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.Ar scn
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were NULL.
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.It Bq Er ELF_E_ARGUMENT
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Argument
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.Ar index
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exceeded the current number of sections in the ELF object.
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.It Bq Er ELF_E_ARGUMENT
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Argument
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.Ar elf
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was not a descriptor for an ELF file.
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.It Bq Er ELF_E_ARGUMENT
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Section descriptor
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.Ar scn
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was not associated with ELF descriptor
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.Ar elf .
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.It Bq Er ELF_E_CLASS
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Descriptor
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.Ar elf
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was of an unknown ELF class.
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.It Bq Er ELF_E_SECTION
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Argument
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.Ar elf
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specified extended section numbering in the ELF header with the section header at
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index
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.Dv SHN_UNDEF
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not being of type
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.Dv SHT_NULL .
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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_flagdata 3 ,
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.Xr elf_flagscn 3 ,
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.Xr elf_getdata 3 ,
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.Xr elf_getshdr 3 ,
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.Xr gelf 3
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