1  .\" Copyright (c) 2006,2008 Joseph Koshy.  All rights reserved.
  2  .\"
  3  .\" Redistribution and use in source and binary forms, with or without
  4  .\" modification, are permitted provided that the following conditions
  5  .\" are met:
  6  .\" 1. Redistributions of source code must retain the above copyright
  7  .\"    notice, this list of conditions and the following disclaimer.
  8  .\" 2. Redistributions in binary form must reproduce the above copyright
  9  .\"    notice, this list of conditions and the following disclaimer in the
 10  .\"    documentation and/or other materials provided with the distribution.
 11  .\"
 12  .\" This software is provided by Joseph Koshy ``as is'' and
 13  .\" any express or implied warranties, including, but not limited to, the
 14  .\" implied warranties of merchantability and fitness for a particular purpose
 15  .\" are disclaimed.  in no event shall Joseph Koshy be liable
 16  .\" for any direct, indirect, incidental, special, exemplary, or consequential
 17  .\" damages (including, but not limited to, procurement of substitute goods
 18  .\" or services; loss of use, data, or profits; or business interruption)
 19  .\" however caused and on any theory of liability, whether in contract, strict
 20  .\" liability, or tort (including negligence or otherwise) arising in any way
 21  .\" out of the use of this software, even if advised of the possibility of
 22  .\" such damage.
 23  .\"
 24  .\" $Id$
 25  .\"
 26  .Dd August 29, 2006
 27  .Os
 28  .Dt GELF_CHECKSUM 3
 29  .Sh NAME
 30  .Nm elf32_checksum ,
 31  .Nm elf64_checksum ,
 32  .Nm gelf_checksum
 33  .Nd return the checksum of an ELF object
 34  .Sh LIBRARY
 35  .Lb libelf
 36  .Sh SYNOPSIS
 37  .In libelf.h
 38  .Ft long
 39  .Fn elf32_checksum "Elf *elf"
 40  .Ft long
 41  .Fn elf64_checksum "Elf *elf"
 42  .In gelf.h
 43  .Ft long
 44  .Fn gelf_checksum "Elf *elf"
 45  .Sh DESCRIPTION
 46  These functions return a simple checksum of the ELF object described
 47  by their argument
 48  .Ar elf .
 49  The checksum is computed in way that allows its value to remain
 50  unchanged in presence of modifications to the ELF object by utilities
 51  like
 52  .Xr strip 1 .
 53  .Pp
 54  Function
 55  .Fn elf32_checksum
 56  returns a checksum for an ELF descriptor
 57  .Ar elf
 58  of class
 59  .Dv ELFCLASS32 .
 60  .Pp
 61  Function
 62  .Fn elf64_checksum
 63  returns a checksum for an ELF descriptor
 64  .Ar elf
 65  of class
 66  .Dv ELFCLASS64 .
 67  .Pp
 68  Function
 69  .Fn gelf_checksum
 70  provides a class-independent way retrieving the checksum
 71  for ELF object
 72  .Ar elf .
 73  .Sh RETURN VALUES
 74  These functions return the checksum of the ELF object, or zero in case
 75  an error was encountered.
 76  .Sh ERRORS
 77  These functions may fail with the following errors:
 78  .Bl -tag -width "[ELF_E_RESOURCE]"
 79  .It Bq Er ELF_E_ARGUMENT
 80  Argument
 81  .Ar elf
 82  was NULL.
 83  .It Bq Er ELF_E_ARGUMENT
 84  Argument
 85  .Ar elf
 86  was not a descriptor for an ELF file.
 87  .It Bq Er ELF_E_ARGUMENT
 88  The ELF descriptor
 89  .Ar elf
 90  was not opened for reading or updating.
 91  .It Bq Er ELF_E_CLASS
 92  For functions
 93  .Fn elf32_checksum
 94  and
 95  .Fn elf64_checksum ,
 96  ELF descriptor
 97  .Ar elf
 98  did not match the class of the called function.
 99  .It Bq Er ELF_E_HEADER
100  The ELF object specified by argument
101  .Ar elf
102  had a malformed executable header.
103  .It Bq Er ELF_E_RESOURCE
104  An out of memory condition was detected during processing.
105  .It Bq Er ELF_E_SECTION
106  The ELF object specified by argument
107  .Ar elf
108  contained a section with a malformed section header.
109  .It Bq Er ELF_E_VERSION
110  The ELF object was of an unsupported version.
111  .El
112  .Sh SEE ALSO
113  .Xr strip 1 ,
114  .Xr elf 3 ,
115  .Xr gelf 3