Tribblix: manual page: elfdump.1

ELFDUMP(1) User Commands ELFDUMP(1)

NAME

elfdump - dumps selected parts of an object file

SYNOPSIS

elfdump [-cCdegGhHiklmnPrsSuvy] [-p | -w file] [-I index-expr]
[-N name] [-O osabi] [-T type] filename...

DESCRIPTION

The elfdump utility symbolically dumps selected parts of the
specified object file(s). The options allow specific portions of the
file to be displayed.

The elfdump utility is similar in function to the dump(1) utility.
The dump utility offers an older and less user-friendly interface
than elfdump, although dump might be more appropriate for certain
uses such as in shell scripts.

Archive files, produced by ar(1), can also be inspected with elfdump.
In this case, each object within the archive is processed using the
options supplied.

elfdump can display the ELF header, program header array, and section
header array for any ELF object. It is also able to display the data
found in the following types of sections:

Category Option ELF Section Type
Dynamic -d SHT_DYNAMIC
Global Offset Table (GOT) -G Special. See below.
Group -g SHT_GROUP
Hardware/Software
Capabilities -H SHT_SUNW_cap
Hash Table -h SHT_HASH
Interpreter -i Special, see below.
Move -m SHT_SUNW_move
Note -n SHT_NOTE
Relocation -r SHT_RELA
SHT_REL
Stack Unwind/Exceptions -u Special. See below.
Syminfo -y SHT_SUNW_syminfo
Symbol Sort -S SHT_SUNW_symsort
SHT_SUNW_tlssort
Symbol Table -s SHT_SYMTAB
SHT_DYNSYM
SHT_SUNW_LDYNSYM
SHT_SUNW_versym
Versioning -v SHT_SUNW_verdef
SHT_SUNW_verneed

Interpreter and global offset table sections do not have a special
ELF section type, but are instead implemented as SHT_PROGBITS
sections with well known names (.interp and .got respectively).
elfdump is able to recognize and display these special sections.

Sections used for stack unwinding and exception handling can have the
ELF section type SHT_PROGBITS, or SHT_AMD64_UNWIND, depending on the
compiler and platform involved. These sections are recognized by
name: .eh_frame, .eh_frame_hdr, and .exception_ranges.

When run without options to narrow the information displayed, elfdump
displays all available information for each object.

For a complete description of the displayed information, refer to the
Linker and Libraries Guide.

OPTIONS

The following options are supported:

-c
Dumps section header information.

-C
Demangles symbol names.

-d
Dumps the contents of the .dynamic section.

-e
Dumps the ELF header.

-g
Dumps the contents of the .group section.

-G
Dumps the contents of the .got section.

-h
Dumps the contents of the .hash section.

-H
Dumps the contents of the .SUNW_cap hardware and
software capabilities section.

-i
Dumps the contents of the .interp section.

-I index-expr
Qualifies the sections or program headers to
examine with a specific index or index range. For
example, the third section header in a file can be
displayed using:

example% elfdump -c -I 3 filename

An index-expr can be a single non-negative integer
value that specifies a specific item, as shown in
the previous example. Alternatively, an index-expr
can consist of two such values separated by a colon
(:), indicating a range of items. The following
example displays the third, fourth, and fifth
program headers in a file:

example% elfdump -p -I 3:5 filename

When specifying an index range, the second value
can be omitted to indicate the final item in the
file. For example, the following statement lists
all section headers from the tenth to the end:

example% elfdump -c -I 10: filename

See Matching Options for additional information
about the matching options (-I, -N, -T).

-k
Calculates the ELF checksum. See
gelf_checksum(3ELF).

-l
Displays long section names without truncation.

-m
Dumps the contents of the .SUNW_move section.

-n
Dumps the contents of .note sections. By default,
elfdump displays this data without interpretation
in hexadecimal form. Core files are an exception. A
subset of the core file notes described in core(5)
are interpreted by elfdump and displayed in a high
level format: NT_PRSTATUS, NT_PRPSINFO,
NT_PLATFORM, NT_AUXV, NT_ASRS, NT_PSTATUS,
NT_PSINFO, NT_PRCRED, NT_UTSNAME, NT_LWPSTATUS,
NT_LWPSINFO, NT_PRPRIV, NT_PRPRIVINFO, NT_CONTENT,
and NT_ZONENAME.

-N name
Qualifies the sections or program headers to
examine with a specific name. For example, in a
file that contains more than one symbol table, the
.dynsym symbol table can be displayed by itself
using:

example% elfdump -N .dynsym filename

ELF program headers do not have names. If the -p
option is specified, name refers to the program
header type, and the behavior of the -N option is
identical to that of the -T option. For example,
the program header that identifies an interpreter
can be displayed using:

example% elfdump -p -N PT_INTERP filename

See Matching Options for additional information
about the matching options (-I, -N, -T).

-O osabi
Specifies the Operating System ABI to apply when
interpreting the object. osabi can be the name or
value of any of the ELFOSABI_ constants found in
/usr/include/sys/elf.h. For convenience, the
ELFOSABI_ prefix may be omitted from these names.
Two osabi values are fully supported: solaris is
the native ABI of the Solaris operating system.
none is the generic ELF ABI. Support for other
operating system ABIs may be incomplete or missing.
Items for which strings are unavailable are
displayed in numeric form.

If -O is not used, and the object ELF header
specifies a non-generic ABI, the ABI specified by
the object is used. If the object specifies the
generic ELF ABI, elfdump searches for a .note.ABI-
tag section, and if found, identifies the object as
having the linux ABI. Otherwise, an object that
specifies the generic ELF ABI is assumed to conform
to the solaris ABI.

-p
Dumps the program headers. Individual program
headers can be specified using the matching options
(-I, -N, -T). See Matching Options for additional
information.

The -p and -w options are mutually exclusive. Only
one of these options can be used in a given elfdump
invocation

-P
Generate and use alternative section header
information based on the information from the
program headers, ignoring any section header
information contained in the file. If the file has
no section headers a warning message is printed and
this option is automatically selected. Section
headers are not used by the system to execute a
program. As such, a malicious program can have its
section headers stripped or altered to provide
misleading information. In contrast the program
headers must be accurate for the program to be
runnable. The use of synthetic section header
information derived from the program headers allows
files with altered section headers to be examined.

-r
Dumps the contents of the .rel[a] relocation
sections.

-s
Dumps the contents of the .SUNW_ldynsym, .dynsym,
and .symtab symbol table sections. For archives,
the archive symbol table is also dumped. Individual
sections can be specified with the matching options
(-I, -N, -T). An archive symbol table can be
specified using the special section name -N ARSYM.

In the case of core files, the shndx field has the
value "unknown" since the field does not contain
the valid values.

In addition to the standard symbol table
information, the version definition index of the
symbol is also provided under the ver heading.

See Matching Options for additional information
about the matching options (-I, -N, -T).

-S
Dumps the contents of the .SUNW_ldynsym and .dynsym
symbol table sections sorted in the order given by
the .SUNW_dynsymsort and .SUNW_dyntlssort symbol
sort sections. Thread Local Storage (TLS) symbols
are sorted by offset. Regular symbols are sorted by
address. Symbols not referenced by the sort
sections are not displayed.

-T type
Qualifies the sections or program headers to
examine with a specific type. For example, in a
file that contains more than one symbol table, the
.dynsym symbol table can be displayed by itself
using:

example% elfdump -T SHT_DYNSYM filename

The value of type can be a numeric value, or any of
the SHT_ symbolic names defined in
/usr/include/sys/elf.h. The SHT_ prefix is
optional, and type is case insensitive. Therefore,
the above example can also be written as:

example% elfdump -T dynsym filename

If the -p option is specified, type refers to the
program header type, which allows for the display
of specific program headers. For example, the
program header that identifies an interpreter can
be displayed using:

example% elfdump -p -T PT_INTERP filename

The value of type can be a numeric value, or any of
the PT_ symbolic names defined in
/usr/include/sys/elf.h. The PT_ prefix is optional,
and type is case insensitive. Therefore, the above
example can also be written as:

example% elfdump -p -T interp filename

See Matching Options for additional information
about the matching options (-I, -N, -T).

-u
Dumps the contents of sections used for stack frame
unwinding and exception processing.

-v
Dumps the contents of the .SUNW_version version
sections.

-w file
Writes the contents of sections which are specified
with the matching options (-I, -N, -T) to the named
file. For example, extracting the .text section of
a file can be carried out with:

example% elfdump -w text.out -N .text filename

See Matching Options for additional information
about the matching options (-I, -N, -T).

The -p and -w options are mutually exclusive. Only
one of these options can be used in a given elfdump
invocation

-y
Dumps the contents of the .SUNW_syminfo section.

OPERANDS

The following operand is supported:

filename
The name of the specified object file.

USAGE

Matching Options

The options -I, -N, and -T are collectively referred to as the
matching options. These options are used to narrow the range of
program headers or sections to examine, by index, name, or type.

The exact interpretation of the matching options depends on the other
options used:

o When used with the -p option, the matching options
reference program headers. -I refers to program header
indexes. -T refers to program header types. As program
headers do not have names, the -N option behaves
identically to -T for program headers.

o The matching options are used to select sections by index,
name, or type when used with any of the options -c, -g,
-m, -n, -r, -s, -S, -u, or -w.

o If matching options are used alone without any of the
options -c, -g, -m, -n, -p-r, -s, -S, -u, or -w, then
elfdump examines each object, and displays the contents of
any sections matched.

Any number and type of matching option can be mixed in a given
invocation of elfdump. In this case, elfdump displays the superset of
all items matched by any of the matching options used. This feature
allows for the selection of complex groupings of items using the most
convenient form for specifying each item.

FILES

liblddbg.so
linker debugging library

ATTRIBUTES