illumos: 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