man/man1/ctfdump.1

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.\" Copyright 2018, Joyent, Inc.
.\" Copyright 2022 Oxide Computer Company
.\"
.Dd September 20, 2021
.Dt CTFDUMP 1
.Os
.Sh NAME
.Nm ctfdump
.Nd dump parts of ctf data from files
.Sh SYNOPSIS
.Nm ctfdump
.Op Fl cdfhlsSt
.Op Fl p Ar parent
.Op Fl u Ar outfile
.Ar file
.Sh DESCRIPTION
The
.Nm
utility dumps and decodes the
.Sy CTF
data contained inside of
.Sy ELF
objects and raw
.Sy CTF
files.
.Pp
.Nm
can dump information about the CTF header, the labels encoded in the
CTF container, the types of data objects, the internal string table,
the types of the return function and the arguments for functions,
and of course, it displays information about the types defined in the
CTF container.
.Pp
.Nm
can also be used to dump out the raw CTF data and send it to another
file.
When writing out data, it always ensures that the CTF data is
decompressed.
In this form, the CTF data can be inspected using
.Nm
and other tools such as
.Xr mdb 1 .
.Pp
.Nm
in
.Fl c
mode will generate C-style output, which can be used for comparison.
Note that this output is not directly compilable.
.Pp
When no options are specified,
.Nm
displays all information, except the C-style output.
However, when the
.Fl u
option is used, then no information is displayed by default, unless
requested through the appropriate option.
.Sh OPTIONS
The following options are supported:
.Bl -tag -width Ds
.It Fl c
Generate C-style output.
.It Fl d
Dump the types of symbols that correspond to objects.
.It Fl f
Dump the types of the return values and arguments of the functions.
.It Fl h
Dump the CTF header
.It Fl l
Dump all CTF labels associated with the file.
.It Fl p Ar parent
Use the type information in
.Ar parent
to supplement output.
This is useful when a
.Nm
CTF container has been uniquified against
.Ar parent .
This allows
.Nm
to use the names of types when used with
.Fl t .
.It Fl s
Dump the internal CTF string table
.It Fl S
Displays statistics about the CTF container.
.It Fl t
Dump the type information contained in the CTF container.
.It Fl u Ar outfile
Copies the uncompressed CTF data to the file specified by
.Ar outfile .
This can be used to make it easier to inspect the raw CTF data.
.El
.Sh OUTPUT
When the
.Nm
utility is executed with its default options, it prints out a textual
representation of the CTF information.
Note, the output format of
.Nm
is subject to change at any time and should not be relied upon as a
stable format to be used for parsing.
.Ss CTF Header
This section describes the values in the CTF header.
Each line in the section describes the value of one of the
members of the header.
For more information on the meaning and interpretation of these members,
see
.Xr ctf 5 .
.Ss Label Table
This section describes information about the labels present in the CTF
information.
Each entry in this section, if present, starts with a
number and is followed by a string.
An example entry in the label section might look like:
.Bd -literal
\&...
   2270 joyent_20151001T070028Z
\&...
.Ed
.Pp
The number,
.Em 2270 ,
represents the last type that the label applies to.
The string,
.Em joyent_20151001T070028Z ,
is the name of the label.
In this case, if there were no other labels,
it would indicate that the label applied to all types up to, and
including, the type number 2270.
For more information on how labels are used with CTF
information, see the section
.Em The Label Section
in
.Xr ctf 5 .
.Ss Data Objects
This section describes the type information relating to data objects
from the symbol table.
An entry for a data object consists of four columns.
The first column is just a monotonic ID.
The second number is the type id of the object.
The third column is the name of the symbol and the fourth column is the
corresponding index from the symbol table.
.Pp
Take for example, the following couple of entries:
.Bd -literal
\&...
  [0] 13        hz (48)
  [1] 78        _nd (49)
  [2] 1656      __pfmt_label (56)
  [3] 926       _aio_hash (68)
  [4] 13        _lio_free (70)
  [5] 1321      u8_number_of_bytes (73)
\&...
.Ed
.Pp
Let's take the first entry in the list above.
The symbol is named
.Sy hz .
It is the first data object, as indicated by the number zero in
brackets.
It has a type id of 13 and in this case, it has a symbol table index of
48.
.Ss Functions
This section describes the type information for functions.
For each function present in the symbol table with type information, the
function's entry into the function section, the function's name, the
function's symbol table index, the function's return type, and the types
of the function's arguments are printed.
If a function is a variadic function, then the variadic argument is
printed as the string
.Sy '...' .
.Pp
Take for example, the following couple of entries:
.Bd -literal
\&...
  [687] pfprint_stack (3110) returns: 11 args: (385, 115, 29, 1704, 223, 116, 2)
  [688] pfprint_stddev (3111) returns: 11 args: (385, 115, 29, 1704, 223, 116, 2)
  [689] pfprint_quantize (3112) returns: 11 args: (385, 115, 29, 1704, 223, 116, 2)
  [690] pfprint_lquantize (3113) returns: 11 args: (385, 115, 29, 1704, 223, 116, 2)
  [691] pfprint_llquantize (3114) returns: 11 args: (385, 115, 29, 1704, 223, 116, 2)
\&...
.Ed
.Pp
The first column is the function's entry number in the function type
information section.
It is enclosed in brackets.
The next column is the function's name and it is followed in parenthesis
by the its index in the
symbol table.
The following portions of this entry describe the return
type and then all of the arguments, in positional order.
.Ss Types
The types section gives information about each type in the CTF
container.
Each entry begins with its type identifier.
The type identifier may either be in square brackets or in angle
brackets.
If the type identifier is enclosed in angle brackets, then that
represents that it is a root type or top-level type.
If it is square brackets, then it is not.
For more information on root types, see
.Xr ctf 5 .
.Pp
Next, the type will have its name and kind.
If it is an array, it will be followed with a subscript that describes
the number of entries in the array.
If it is a pointer, it will followed by the
.Sy *
symbol to indicate that it is a pointer.
If the type has the
.Sy const ,
.Sy volatile ,
.Sy typedef ,
or
.Sy restrict
keyword applied to it, that will precede the name.
All of these reference types, including pointer, will then be followed
with an example of the type that they refer to.
.Pp
Types which are an integral or floating point value will be followed by
information about their encoding and the number of bits represented in
the type.
.Pp
Arrays will be followed by two different entries, the contents and
index.
The contents member contains the type id of the array's contents
and the index member describes a type which can represent the array's
index.
.Pp
Structures and unions will be preceded with the corresponding C keyword,
.Sy struct
or
.Sy union .
After that, the size in bytes of the structure will be indicated.
On each subsequent line, a single member will be listed.
That line will contain the member's name, it's type identifier, and the
offset into the structure that the member starts at.
The first values is in bits, which is what CTF encodes.
It is then followed by bytes and the bit offset into the byte.
That is the value
.Sq 2.5
indicates that it starts at the 5th bit in the 2nd byte
.Pq i.e. bit 21 .
.Pp
The following show examples of type information for all of these
different types:
.Bd -literal
\&...
  [155] struct ctf_merge_handle (80 bytes)
        cmh_inputs type=165 off=0 bits (0.0 bytes)
        cmh_ninputs type=6 off=256 bits (32.0 bytes)
        cmh_nthreads type=6 off=288 bits (36.0 bytes)
        cmh_unique type=65 off=320 bits (40.0 bytes)
        cmh_msyms type=115 off=384 bits (48.0 bytes)
        cmh_ofd type=34 off=416 bits (52.0 bytes)
        cmh_flags type=34 off=448 bits (56.0 bytes)
        cmh_label type=94 off=512 bits (64.0 bytes)
        cmh_pname type=94 off=576 bits (72.0 bytes)

  <156> typedef ctf_merge_t refers to 155
  [157] struct __va_list_tag (24 bytes)
        gp_offset type=5 off=0 bits (0.0 bytes)
        fp_offset type=5 off=32 bits (4.0 bytes)
        overflow_arg_area type=41 off=64 bits (8.0 bytes)
        reg_save_area type=41 off=128 bits (16.0 bytes)

  [158] struct __va_list_tag [1] contents: 157, index: 9
\&...
.Ed
.Ss String Table
This section describes all of the strings that are present in the CTF
container.
Each line represents an entry in the string table.
First the byte offset into the string table is shown in brackets and
then the
string's value is displayed.
Note the following examples:
.Bd -literal
  [0] \e0
  [1] joyent_20151001T070028Z
  [25] char
  [30] long
  [35] short
.Ed
.Ss Statistics
This section contains miscellaneous statistics about the CTF data
present.
Each line contains a single statistic.
A brief explanation of the statistic is placed first, followed by an
equals sign, and then finally the value.
.Sh EXIT STATUS
.Bl -tag -width Ds
.It Sy 0
Execution completed successfully.
.It Sy 1
A fatal error occurred.
.It Sy 2
Invalid command line options were specified.
.El
.Sh EXAMPLES
.Sy Example 1
Displaying the Type Section of a Single File
.Pp
The following example dumps the type section of the file
.Sy /usr/lib/libc.so.1 .
.Bd -literal -offset 6n
$ ctfdump -t /usr/lib/libc.so.1
- Types ----------------------------------------------------

  <1> int encoding=SIGNED offset=0 bits=32
  <2> long encoding=SIGNED offset=0 bits=32
  <3> typedef pid_t refers to 2
  <4> unsigned int encoding=0x0 offset=0 bits=32
  <5> typedef uid_t refers to 4
  <6> typedef gid_t refers to 5
  <7> typedef uintptr_t refers to 4
\&...
.Ed
.Pp
.Sy Example 2
Dumping the CTF data to Another File
.Pp
The following example dumps the entire CTF data from the file
.Sy /usr/lib/libc.so.1
and places it into the file
.Sy ctf.out .
This then shows how you can use the
.Xr mdb 1
to inspect its contents.
.Bd -literal -offset 6n
$ ctfdump -u ctf.out /usr/lib/libc.so.1
$ mdb ./ctf.out
> ::typedef -r /usr/lib/libctf.so.1
> 0::print ctf_header_t
{
    cth_preamble = {
        ctp_magic = 0xcff1
        ctp_version = 0x2
        ctp_flags = 0
    }
    cth_parlabel = 0
    cth_parname = 0
    cth_lbloff = 0
    cth_objtoff = 0x8
    cth_funcoff = 0x5e0
    cth_typeoff = 0x7178
    cth_stroff = 0x12964
    cth_strlen = 0x7c9c
}
.Ed
.Pp
.Sy Example 3
Dumping C-style output
.Bd -literal -offset 6n
$ ctfdump -c ./genunix | more
/* Types */

typedef Elf64_Addr Addr;

typedef unsigned char Bool;

typedef struct CK_AES_CCM_PARAMS CK_AES_CCM_PARAMS;

typedef struct CK_AES_GCM_PARAMS CK_AES_GCM_PARAMS;
\&...
.Ed
.Sh INTERFACE STABILITY
The command syntax is
.Sy Committed .
The output format is
.Sy Uncommitted .
.Sh SEE ALSO
.Xr ctfdiff 1 ,
.Xr dump 1 ,
.Xr elfdump 1 ,
.Xr mdb 1 ,
.Xr ctf 5