readelf(1) - Man pages

READELF(1) GNU Development Tools READELF(1)

NAME
readelf - display information about ELF files

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. This option can be repeated multiple times
on the command line in order to request multiple hex dumps.

-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. This option can be repeated
multiple times on the command line in order to request multiple
relocated dumps.

-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. This option can be repeated multiple times on the
command line in order to request multiple string dumps.

-j <number or name>
--display-section
Displays the contents of the indicated section according to its
section header type. Sections containing relocations will be
displayed as if the --relocations option had been used, sections
contains symbols will be displayed as if the --syms option had been
used and so on.

A number identifies a particular section by index in the section
table; any other string identifies all sections with that name in
the input file(s).

This option can be repeated multiple times on the command line in
order to request multiple section dumps.

-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-parent-section=section
This option lets you pick a completely different section for the CTF
parent dictionary containing unambiguous types than for the child
dictionaries that contain the ambiguous remainder. The linker does
not emit ELF objects structured like this, but some third-party
linkers may. It's also convenient to inspect CTF written out as
multiple raw files to compose them with objcopy, which can put them
in different ELF sections but not in different members of a single
CTF dict.

--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.

SEE ALSO
objdump(1), and the Info entries for binutils.

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".

binutils-2.44 2025-03-03 READELF(1)

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