ae500c1ff8
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
108 lines
3.5 KiB
Groff
108 lines
3.5 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: elf_errmsg.3 3639 2018-10-14 14:07:02Z jkoshy $
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.\"
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.Dd June 11, 2006
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.Dt ELF_ERRMSG 3
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.Os
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.Sh NAME
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.Nm elf_errmsg ,
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.Nm elf_errno
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.Nd ELF library error message handling
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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 int
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.Fn elf_errno "void"
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.Ft "const char *"
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.Fn elf_errmsg "int error"
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.Sh DESCRIPTION
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When an error occurs during an ELF library API call, the library
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encodes the error using an error number and stores the error number
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internally for retrieval by the application at a later point of time.
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Error numbers may contain an OS supplied error code in addition to
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an ELF API specific error code.
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An error number value of zero indicates no error.
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.Pp
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Function
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.Fn elf_errno
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is used to retrieve the last error recorded by the ELF library.
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Invoking this function has the side-effect of resetting the
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ELF library's recorded error number to zero.
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.Pp
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The function
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.Fn elf_errmsg
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returns a null-terminated string with a human readable
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description of the error specified in argument
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.Ar error .
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A zero value for argument
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.Ar error
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retrieves the most recent error encountered by the ELF
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library.
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An argument value of -1 behaves identically, except that
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it guarantees a non-NULL return from
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.Fn elf_errmsg .
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.Sh RETURN VALUES
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Function
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.Fn elf_errno
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returns a non-zero value encoding the last error encountered
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by the ELF library, or zero if no error was encountered.
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.Pp
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Function
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.Fn elf_errmsg
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returns a pointer to library local storage for non-zero values
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of argument
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.Ar error .
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With a zero argument, the function will return a NULL pointer if no
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error had been encountered by the library, or will return a pointer to
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library local storage containing an appropriate message otherwise.
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.Sh EXAMPLES
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Clearing the ELF library's recorded error number can be accomplished
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by invoking
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.Fn elf_errno
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and discarding its return value.
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.Bd -literal -offset indent
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/* clear error */
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(void) elf_errno();
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.Ed
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.Pp
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Retrieving a human-readable description of the current error number
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can be done with the following snippet:
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.Bd -literal -offset indent
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int err;
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const char *errmsg;
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\&...
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err = elf_errno();
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if (err != 0)
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errmsg = elf_errmsg(err);
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.Ed
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.Sh SEE ALSO
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.Xr elf 3 ,
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.Xr gelf 3
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.Sh BUGS
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Function
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.Fn elf_errmsg
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is not localized.
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