Ubuntu Manpage: readelf - display information about ELF files

Provided by: binutils-common_2.42-4ubuntu2.3_amd64

NAME

       readelf - display information about ELF files

SYNOPSIS

       readelf [-a|--all]
               [-h|--file-header]
               [-l|--program-headers|--segments]
               [-S|--section-headers|--sections]
               [-g|--section-groups]
               [-t|--section-details]
               [-e|--headers]
               [-s|--syms|--symbols]
               [--dyn-syms|--lto-syms]
               [--sym-base=[0|8|10|16]]
               [--demangle=style|--no-demangle]
               [--quiet]
               [--recurse-limit|--no-recurse-limit]
               [-U method|--unicode=method]
               [-X|--extra-sym-info|--no-extra-sym-info]
               [-n|--notes]
               [-r|--relocs]
               [-u|--unwind]
               [-d|--dynamic]
               [-V|--version-info]
               [-A|--arch-specific]
               [-D|--use-dynamic]
               [-L|--lint|--enable-checks]
               [-x <number or name>|--hex-dump=<number or name>]
               [-p <number or name>|--string-dump=<number or name>]
               [-R <number or name>|--relocated-dump=<number or name>]
               [-z|--decompress]
               [-c|--archive-index]
               [-w[lLiaprmfFsoORtUuTgAck]|
                --debug-dump[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=str-offsets,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index,=addr,=cu_index,=links]]
               [-wK|--debug-dump=follow-links]
               [-wN|--debug-dump=no-follow-links]
               [-wD|--debug-dump=use-debuginfod]
               [-wE|--debug-dump=do-not-use-debuginfod]
               [-P|--process-links]
               [--dwarf-depth=n]
               [--dwarf-start=n]
               [--ctf=section]
               [--ctf-parent=section]
               [--ctf-symbols=section]
               [--ctf-strings=section]
               [--sframe=section]
               [-I|--histogram]
               [-v|--version]
               [-W|--wide]
               [-T|--silent-truncation]
               [-H|--help]
               elffile...

DESCRIPTION

       readelf displays information about one or more ELF format object files.  The options
       control what particular information to display.

       elffile... are the object files to be examined.  32-bit and 64-bit ELF files are
       supported, as are archives containing ELF files.

       This program performs a similar function to objdump but it goes into more detail and it
       exists independently of the BFD library, so if there is a bug in BFD then readelf will not
       be affected.

OPTIONS

The long and short forms of options, shown here as alternatives, are equivalent. At least
one option besides -v or -H must be given.

-a
--all
Equivalent to specifying --file-header, --program-headers, --sections, --symbols,
--relocs, --dynamic, --notes, --version-info, --arch-specific, --unwind,
--section-groups and --histogram.

Note - this option does not enable --use-dynamic itself, so if that option is not
present on the command line then dynamic symbols and dynamic relocs will not be
displayed.

-h
--file-header
Displays the information contained in the ELF header at the start of the file.

-l
--program-headers
--segments
Displays the information contained in the file's segment headers, if it has any.

--quiet
Suppress "no symbols" diagnostic.

-S
--sections
--section-headers
Displays the information contained in the file's section headers, if it has any.

-g
--section-groups
Displays the information contained in the file's section groups, if it has any.

-t
--section-details
Displays the detailed section information. Implies -S.

-s
--symbols
--syms
Displays the entries in symbol table section of the file, if it has one. If a symbol
has version information associated with it then this is displayed as well. The
version string is displayed as a suffix to the symbol name, preceded by an @
character. For example foo@VER_1. If the version is the default version to be used
when resolving unversioned references to the symbol then it is displayed as a suffix
preceded by two @ characters. For example foo@@VER_2.

--dyn-syms
Displays the entries in dynamic symbol table section of the file, if it has one. The
output format is the same as the format used by the --syms option.

--lto-syms
Displays the contents of any LTO symbol tables in the file.

--sym-base=[0|8|10|16]
Forces the size field of the symbol table to use the given base. Any unrecognized
options will be treated as 0. --sym-base=0 represents the default and legacy
behaviour. This will output sizes as decimal for numbers less than 100000. For sizes
100000 and greater hexadecimal notation will be used with a 0x prefix. --sym-base=8
will give the symbol sizes in octal. --sym-base=10 will always give the symbol sizes
in decimal. --sym-base=16 will always give the symbol sizes in hexadecimal with a 0x
prefix.

-C
--demangle[=style]
Decode (demangle) low-level symbol names into user-level names. This makes C++
function names readable. Different compilers have different mangling styles. The
optional demangling style argument can be used to choose an appropriate demangling
style for your compiler.

--no-demangle
Do not demangle low-level symbol names. This is the default.

--recurse-limit
--no-recurse-limit
--recursion-limit
--no-recursion-limit
Enables or disables a limit on the amount of recursion performed whilst demangling
strings. Since the name mangling formats allow for an infinite level of recursion it
is possible to create strings whose decoding will exhaust the amount of stack space
available on the host machine, triggering a memory fault. The limit tries to prevent
this from happening by restricting recursion to 2048 levels of nesting.

The default is for this limit to be enabled, but disabling it may be necessary in
order to demangle truly complicated names. Note however that if the recursion limit
is disabled then stack exhaustion is possible and any bug reports about such an event
will be rejected.

-U [d|i|l|e|x|h]
--unicode=[default|invalid|locale|escape|hex|highlight]
Controls the display of non-ASCII characters in identifier names. The default
(--unicode=locale or --unicode=default) is to treat them as multibyte characters and
display them in the current locale. All other versions of this option treat the bytes
as UTF-8 encoded values and attempt to interpret them. If they cannot be interpreted
or if the --unicode=invalid option is used then they are displayed as a sequence of
hex bytes, encloses in curly parethesis characters.

Using the --unicode=escape option will display the characters as as unicode escape
sequences (\uxxxx). Using the --unicode=hex will display the characters as hex byte
sequences enclosed between angle brackets.

Using the --unicode=highlight will display the characters as unicode escape sequences
but it will also highlighted them in red, assuming that colouring is supported by the
output device. The colouring is intended to draw attention to the presence of unicode
sequences when they might not be expected.

-X
--extra-sym-info
When displaying details of symbols, include extra information not normally presented.
Currently this just adds the name of the section referenced by the symbol's index
field, if there is one. In the future more information may be displayed when this
option is enabled.

Enabling this option effectively enables the --wide option as well, at least when
displaying symbol information.

--no-extra-sym-info
Disables the effect of the --extra-sym-info option. This is the default.

-e
--headers
Display all the headers in the file. Equivalent to -h -l -S.

-n
--notes
Displays the contents of the NOTE segments and/or sections, if any.

-r
--relocs
Displays the contents of the file's relocation section, if it has one.

-u
--unwind
Displays the contents of the file's unwind section, if it has one. Only the unwind
sections for IA64 ELF files, as well as ARM unwind tables (".ARM.exidx" /
".ARM.extab") are currently supported. If support is not yet implemented for your
architecture you could try dumping the contents of the .eh_frames section using the
--debug-dump=frames or --debug-dump=frames-interp options.

-d
--dynamic
Displays the contents of the file's dynamic section, if it has one.

-V
--version-info
Displays the contents of the version sections in the file, it they exist.

-A
--arch-specific
Displays architecture-specific information in the file, if there is any.

-D
--use-dynamic
When displaying symbols, this option makes readelf use the symbol hash tables in the
file's dynamic section, rather than the symbol table sections.

When displaying relocations, this option makes readelf display the dynamic relocations
rather than the static relocations.

-L
--lint
--enable-checks
Displays warning messages about possible problems with the file(s) being examined. If
used on its own then all of the contents of the file(s) will be examined. If used
with one of the dumping options then the warning messages will only be produced for
the things being displayed.

-x <number or name>
--hex-dump=<number or name>
Displays the contents of the indicated section as a hexadecimal bytes. A number
identifies a particular section by index in the section table; any other string
identifies all sections with that name in the object file.

-R <number or name>
--relocated-dump=<number or name>
Displays the contents of the indicated section as a hexadecimal bytes. A number
identifies a particular section by index in the section table; any other string
identifies all sections with that name in the object file. The contents of the
section will be relocated before they are displayed.

-p <number or name>
--string-dump=<number or name>
Displays the contents of the indicated section as printable strings. A number
identifies a particular section by index in the section table; any other string
identifies all sections with that name in the object file.

-z
--decompress
Requests that the section(s) being dumped by x, R or p options are decompressed before
being displayed. If the section(s) are not compressed then they are displayed as is.

-c
--archive-index
Displays the file symbol index information contained in the header part of binary
archives. Performs the same function as the t command to ar, but without using the
BFD library.

-w[lLiaprmfFsOoRtUuTgAckK]
--debug-dump[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=str-offsets,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index,=addr,=cu_index,=links,=follow-links]
Displays the contents of the DWARF debug sections in the file, if any are present.
Compressed debug sections are automatically decompressed (temporarily) before they are
displayed. If one or more of the optional letters or words follows the switch then
only those type(s) of data will be dumped. The letters and words refer to the
following information:

"a"
"=abbrev"
Displays the contents of the .debug_abbrev section.

"A"
"=addr"
Displays the contents of the .debug_addr section.

"c"
"=cu_index"
Displays the contents of the .debug_cu_index and/or .debug_tu_index sections.

"f"
"=frames"
Display the raw contents of a .debug_frame section.

"F"
"=frames-interp"
Display the interpreted contents of a .debug_frame section.

"g"
"=gdb_index"
Displays the contents of the .gdb_index and/or .debug_names sections.

"i"
"=info"
Displays the contents of the .debug_info section. Note: the output from this
option can also be restricted by the use of the --dwarf-depth and --dwarf-start
options.

"k"
"=links"
Displays the contents of the .gnu_debuglink, .gnu_debugaltlink and .debug_sup
sections, if any of them are present. Also displays any links to separate dwarf
object files (dwo), if they are specified by the DW_AT_GNU_dwo_name or
DW_AT_dwo_name attributes in the .debug_info section.

"K"
"=follow-links"
Display the contents of any selected debug sections that are found in linked,
separate debug info file(s). This can result in multiple versions of the same
debug section being displayed if it exists in more than one file.

In addition, when displaying DWARF attributes, if a form is found that references
the separate debug info file, then the referenced contents will also be displayed.

Note - in some distributions this option is enabled by default. It can be
disabled via the N debug option. The default can be chosen when configuring the
binutils via the --enable-follow-debug-links=yes or --enable-follow-debug-links=no
options. If these are not used then the default is to enable the following of
debug links.

Note - if support for the debuginfod protocol was enabled when the binutils were
built then this option will also include an attempt to contact any debuginfod
servers mentioned in the DEBUGINFOD_URLS environment variable. This could take
some time to resolve. This behaviour can be disabled via the
=do-not-use-debuginfod debug option.

"N"
"=no-follow-links"
Disables the following of links to separate debug info files.

"D"
"=use-debuginfod"
Enables contacting debuginfod servers if there is a need to follow debug links.
This is the default behaviour.

"E"
"=do-not-use-debuginfod"
Disables contacting debuginfod servers when there is a need to follow debug links.

"l"
"=rawline"
Displays the contents of the .debug_line section in a raw format.

"L"
"=decodedline"
Displays the interpreted contents of the .debug_line section.

"m"
"=macro"
Displays the contents of the .debug_macro and/or .debug_macinfo sections.

"o"
"=loc"
Displays the contents of the .debug_loc and/or .debug_loclists sections.

"O"
"=str-offsets"
Displays the contents of the .debug_str_offsets section.

"p"
"=pubnames"
Displays the contents of the .debug_pubnames and/or .debug_gnu_pubnames sections.

"r"
"=aranges"
Displays the contents of the .debug_aranges section.

"R"
"=Ranges"
Displays the contents of the .debug_ranges and/or .debug_rnglists sections.

"s"
"=str"
Displays the contents of the .debug_str, .debug_line_str and/or .debug_str_offsets
sections.

"t"
"=pubtype"
Displays the contents of the .debug_pubtypes and/or .debug_gnu_pubtypes sections.

"T"
"=trace_aranges"
Displays the contents of the .trace_aranges section.

"u"
"=trace_abbrev"
Displays the contents of the .trace_abbrev section.

"U"
"=trace_info"
Displays the contents of the .trace_info section.

Note: displaying the contents of .debug_static_funcs, .debug_static_vars and
debug_weaknames sections is not currently supported.

--dwarf-depth=n
Limit the dump of the ".debug_info" section to n children. This is only useful with
--debug-dump=info. The default is to print all DIEs; the special value 0 for n will
also have this effect.

With a non-zero value for n, DIEs at or deeper than n levels will not be printed. The
range for n is zero-based.

--dwarf-start=n
Print only DIEs beginning with the DIE numbered n. This is only useful with
--debug-dump=info.

If specified, this option will suppress printing of any header information and all
DIEs before the DIE numbered n. Only siblings and children of the specified DIE will
be printed.

This can be used in conjunction with --dwarf-depth.

-P
--process-links
Display the contents of non-debug sections found in separate debuginfo files that are
linked to the main file. This option automatically implies the -wK option, and only
sections requested by other command line options will be displayed.

--ctf[=section]
Display the contents of the specified CTF section. CTF sections themselves contain
many subsections, all of which are displayed in order.

By default, display the name of the section named .ctf, which is the name emitted by
ld.

--ctf-parent=member
If the CTF section contains ambiguously-defined types, it will consist of an archive
of many CTF dictionaries, all inheriting from one dictionary containing unambiguous
types. This member is by default named .ctf, like the section containing it, but it
is possible to change this name using the "ctf_link_set_memb_name_changer" function at
link time. When looking at CTF archives that have been created by a linker that uses
the name changer to rename the parent archive member, --ctf-parent can be used to
specify the name used for the parent.

--ctf-symbols=section
--ctf-strings=section
Specify the name of another section from which the CTF file can inherit strings and
symbols. By default, the ".symtab" and its linked string table are used.

If either of --ctf-symbols or --ctf-strings is specified, the other must be specified
as well.

-I
--histogram
Display a histogram of bucket list lengths when displaying the contents of the symbol
tables.

-v
--version
Display the version number of readelf.

-W
--wide
Don't break output lines to fit into 80 columns. By default readelf breaks section
header and segment listing lines for 64-bit ELF files, so that they fit into 80
columns. This option causes readelf to print each section header resp. each segment
one a single line, which is far more readable on terminals wider than 80 columns.

-T
--silent-truncation
Normally when readelf is displaying a symbol name, and it has to truncate the name to
fit into an 80 column display, it will add a suffix of "[...]" to the name. This
command line option disables this behaviour, allowing 5 more characters of the name to
be displayed and restoring the old behaviour of readelf (prior to release 2.35).

-H
--help
Display the command-line options understood by readelf.

@file
Read command-line options from file. The options read are inserted in place of the
original @file option. If file does not exist, or cannot be read, then the option
will be treated literally, and not removed.

Options in file are separated by whitespace. A whitespace character may be included
in an option by surrounding the entire option in either single or double quotes. Any
character (including a backslash) may be included by prefixing the character to be
included with a backslash. The file may itself contain additional @file options; any
such options will be processed recursively.

COPYRIGHT

       Copyright (c) 1991-2024 Free Software Foundation, Inc.

       Permission is granted to copy, distribute and/or modify this document under the terms of
       the GNU Free Documentation License, Version 1.3 or any later version published by the Free
       Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no
       Back-Cover Texts.  A copy of the license is included in the section entitled "GNU Free
       Documentation License".

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

SEE ALSO

COPYRIGHT