READELF

Section: GNU Development Tools (1)
Updated: 2020-09-19
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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]
        [-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[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]]
        [--dwarf-depth=n]
        [--dwarf-start=n]
        [--ctf=section]
        [--ctf-parent=section]
        [--ctf-symbols=section]
        [--ctf-strings=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.

-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, preceeded 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 preceeded 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.

-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>

-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"
"=frame-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 and/or .gnu_debugaltlink sections. 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.
"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.

--ctf=section

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

--ctf-parent=section

Specify the name of another section from which the CTF dictionary can inherit types. (If none is specified, we assume the CTF dictionary inherits types from the default-named member of the archive contained within this section.)

--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

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''.