b54d7a9715
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
179 lines
4.5 KiB
Groff
179 lines
4.5 KiB
Groff
.\" Copyright (c) 2009 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: dwarf_init.3 3644 2018-10-15 19:55:01Z jkoshy $
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.\"
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.Dd November 9, 2011
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.Dt DWARF_INIT 3
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.Os
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.Sh NAME
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.Nm dwarf_init ,
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.Nm dwarf_elf_init
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.Nd allocate a DWARF debug descriptor
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.Sh LIBRARY
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.Lb libdwarf
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.Sh SYNOPSIS
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.In libdwarf.h
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.Ft int
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.Fo dwarf_init
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.Fa "int fd"
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.Fa "int mode"
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.Fa "Dwarf_Handler errhand"
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.Fa "Dwarf_Ptr errarg"
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.Fa "Dwarf_Debug *ret"
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.Fa "Dwarf_Error *err"
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.Fc
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.Ft in
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.Fo dwarf_elf_init
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.Fa "Elf *elf"
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.Fa "int mode"
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.Fa "Dwarf_Handler errhand"
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.Fa "Dwarf_Ptr errarg"
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.Fa "Dwarf_Debug *ret"
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.Fa "Dwarf_Error *err"
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.Fc
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.Sh DESCRIPTION
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These functions allocate and return a
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.Vt Dwarf_Debug
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instance for the object denoted by argument
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.Ar fd
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or
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.Ar elf .
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This instance would be used for subsequent access to debugging information in the object by other functions in the DWARF(3) library.
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.Pp
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For function
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.Fn dwarf_init ,
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argument
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.Ar fd
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denotes an open file descriptor referencing a compilation object.
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Function
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.Fn dwarf_init
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implicitly allocates an
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.Vt Elf
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descriptor for argument
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.Ar fd .
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.Pp
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For function
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.Fn dwarf_elf_init ,
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argument
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.Ar elf
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denotes a descriptor returned by
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.Xr elf_begin 3
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or
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.Xr elf_memory 3 .
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.Pp
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Argument
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.Ar mode
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specifies the access mode desired.
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It should be at least as permissive as the mode with which
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the file descriptor
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.Ar fd
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or the ELF descriptor
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.Ar elf
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was created with.
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Legal values for argument
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.Ar mode
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are:
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.Pp
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.Bl -tag -width "DW_DLC_WRITE" -compact
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.It DW_DLC_RDWR
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Permit reading and writing of DWARF information.
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.It DW_DLC_READ
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Operate in read-only mode.
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.It DW_DLC_WRITE
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Permit writing of DWARF information.
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.El
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.Pp
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Argument
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.Ar errhand
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denotes a function to be called in case of an error.
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If this argument is
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.Dv NULL
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then a default error handling scheme is used.
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See
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.Xr dwarf 3
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for a description of the error handling scheme used by the
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DWARF(3) library.
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.Pp
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Argument
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.Ar errarg
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is passed to the error handler function denoted by argument
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.Ar errhand
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when it is invoked.
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.Pp
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Argument
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.Ar ret
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points to the memory location that will hold a
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.Vt Dwarf_Debug
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reference on a successful call these functions.
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.Pp
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Argument
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.Ar err
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references a memory location that would hold a
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.Vt Dwarf_Error
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descriptor in case of an error.
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.Ss Memory Management
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The
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.Vt Dwarf_Debug
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instance returned by these functions should be freed using
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.Fn dwarf_finish .
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.Sh IMPLEMENTATION NOTES
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The current implementation does not support access modes
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.Dv DW_DLC_RDWR
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and
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.Dv DW_DLC_WRITE .
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.Sh RETURN VALUES
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These functions return the following values:
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.Bl -tag -width ".Bq Er DW_DLV_NO_ENTRY"
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.It Bq Er DW_DLV_OK
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This return value indicates a successful return.
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.It Bq Er DW_DLV_ERROR
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The operation failed.
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.It Bq Er DW_DLV_NO_ENTRY
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The object specified by arguments
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.Ar "fd"
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or
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.Ar "elf"
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did not contain debug information.
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.El
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.Sh EXAMPLES
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To initialize a
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.Vt Dwarf_Debug
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instance from a open file descriptor referencing an ELF object, and
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with the default error handler, use:
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.Bd -literal -offset indent
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Dwarf_Error err;
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Dwarf_Debug dbg;
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if (dwarf_init(fd, DW_DLC_READ, NULL, NULL, &dbg, &err) !=
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DW_DLV_OK)
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errx(EXIT_FAILURE, "dwarf_init: %s", dwarf_errmsg(err));
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.Ed
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.Sh SEE ALSO
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.Xr dwarf 3 ,
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.Xr dwarf_errmsg 3 ,
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.Xr dwarf_finish 3 ,
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.Xr dwarf_get_elf 3 ,
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.Xr elf_begin 3 ,
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.Xr elf_memory 3
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