.. SPDX-License-Identifier: CC-BY-SA-4.0
.. Copyright (C) 2019 Chris Johns <chrisj@rtems.org>
Dynamic Loader
**************
Introduction
============
The RTEMS shell has the following dynamic loader commands:
- rtl_ - Manage the Run-Time Loader (RTL)
Commands
========
This section details the Dynamic Loader Commands available. A subsection is
dedicated to each of the commands and describes the behavior and configuration
of that command as well as providing an example usage.
.. raw:: latex
\clearpage
.. _rtl:
rtl - Manager the RTL
---------------------
.. index:: rtl
SYNOPSYS:
.. code-block:: none
rtl [-l] -[h] command [...]
DESCRIPTION:
This command manages the Run-time Loader (RTL) using a series of
sub-commands. The sub-command selected determines what is displayed or the
action taken. Sub-commands can have options that modified the behaviour of
the specific command.
The ``-l`` option lists the available commands and ``-h`` displays
a simple help message.
The commands are:
- `list <rtl-list_>`_ : Listings
- `sym <rtl-sym_>`_ : Symbols
- `obj <rtl-obj_>`_ : Object files
- `ar <rtl-ar_>`_ : Archive files
- `call <rtl-call_>`_ : Call symbols
- `trace <rtl-trace_>`_ : Link-editor trace debugging
.. index:: rtl list
.. _rtl-list:
``list``:
List the loaded object files. The executable object file's full path is
displayed. If the executable object file is loaded from an archive the
archive is include in the path. If no options are provided only a list of
the object file names is displayed.
The command is:
.. code-block:: none
rtl list [-nlmsdb] [name]
The options are:
``-n``
Display all the name fields.
``-l``
Long display the RTL's fields:
- ``unresolved`` - number of unresolved symbols
- ``users`` - number of users, ie times loaded
- ``references`` - number of referencs to symbols
- ``symbols`` - number of symbols
- ``symbol memory`` - amount of symbol memory
``-m``
Display the memory map. The sections listed are:
- ``exec`` - total memory allocated
- ``text`` - size of the executable code resident
- ``const`` - size of the constants or read-only memory
- ``data`` - size of the initialised data memory
- ``bss`` - size of the uninitialised data memory
``-s``
Display the local symbols present in the listed object file's symbol
table. List the symbol's value.
``-d``
Display the loaded object files that depend on symbols provided by this
object file. The object file cannot be unloaded while there are
references.
``-b``
Include the base kernel image in the list of object modules. It is not
included by default. If this option is included the base kernel module
name of ``rtems-kernel`` can be used as a ``name``.
``name``
The optional ``name`` argument is a regular expression filter for the
object files to list. The match is partial. If no name argument is
provided all object modules are listed.
.. index:: rtl sym
.. _rtl-sym:
``sym``:
List symbols in the symbol table with their value. Symbols are grouped by
the object file they reside in.
The command is:
.. code-block:: none
rtl sym [-bu] [-o name] [symbol]
The options are:
``-u``
List the system wide unresolved externals. Symbols are not displayed
when displaying unresolved externals.
``-o name``
Display the symbols for the matching object files. The name is a
regular expression and it is a partial match.
``-b``
Include the base kernel image in the list of object modules. It is not
included by default. If this option is included the base kernel module
name of ``rtems-kernel`` can be used as a ``name``.
``symbol``
The optional ``symbol`` argument is a regular expression filter for the
symbols. The match is partial. If no symbol argument is provided all
symbols and their values are displayed.
.. index:: rtl obj
.. _rtl-obj:
``obj``:
Manage object files. The sub-commands control the operation this command
performs.
The command is:
.. code-block:: none
rtl obj [command] [...]
``load <file>``
Load the executable object file specificed by the ``<file>``
argument. The ``file`` argument can be a file or it can be resided in
archive file. The format is ``archive:file``. The ``archive`` is file
name of the archive and ``file`` is the file in the archive.
If the ``<file>`` references symbols in known archive dependent object
files in the available archives they are loaded.
``unload <file>``
Unload the executable object file specificed by the ``<file>``
argument. The ``<file>`` argument can be the object files' name or it
can be a complete name including the archive.
.. index:: rtl ar
.. _rtl-ar:
``ar``:
Display details about archives known to the link editor.
The command is:
.. code-block:: none
rtl ar [-lsd] [name]
The options are:
``-l``
Long display the RTL's archive fields:
- ``size`` - size of the archive in the file system
- ``symbols`` - number of symbols in the archive's symbol search table
- ``refs`` - number of referencs to object files in the archive
- ``flags`` - RTL specific flags
``-s``
Display the symbols in the archive symbol tables
``-d``
Display any duplicate symbols in any archives with the archive the
instance of the symbol.
``name``
The optional ``name`` argument is a regular expression filter for the
archive files to list. The match is partial. If no name argument is
provided all archives known to the link editor are listed.
.. index:: rtl call
.. _rtl-call:
``call``:
Call a symbol that resides in a code (``text``) section of an object
file. Arguments can be passed and there is no return value support.
There are no checks made on the signature of a symbol being called. The
argument signature used needs to match the symbol being called or
unpredictable behaviour may result.
The reference count of the object file containing the symbol is
increased while the call is active. The ``-l`` option locks the object
by not lowering the reference count once the call completes. This is
useful if the call starts a thread in the object file. The reference
count cannot be lowered by the shell and the object file remains locked
in memory.
The call occurs on the stack of the shell so it is important to make
sure there is sufficient space available to meet the needs of the call
when configuring your shell.
The call blocks the shell while it is active. There is no ability to
background the call.
If no arguments are provided the call signature is:
.. code-block:: none
void call (void);
If no options to specify a format are provided and there are arguments
the call signature is the standard ``argc/argv`` call signature:
.. code-block:: none
void call (int argc, const char* argv[]);
The command is:
.. code-block:: none
rtl call [-lsui] name [args]
The options are:
``-l``
Leave the object file the symbol resides in locked after the call
returns.
``-s``
Concatenate the ``[args]`` into a single string and pass as a single
``const char*`` argument. Quoted arguments are stripped or quotes and
merged into the single string. The call signature is:
.. code-block:: none
void call (const char* str);
``-u``
Pass up to four unsigned integer ``[args]`` arguments. The symbol's
call signature can have fewer than four arguments, the unreferenced
arguments are ignored. The call signature is:
.. code-block:: none
void call (unsigned int u1,
unsigned int u2,
unsigned int u3,
unsigned int u4);
``-i``
Pass up to four integer ``[args]`` arguments. The symbol's call
signature can have fewer than four arguments, the unreferenced
arguments are ignored. The call signature is:
.. code-block:: none
void call (int i1, int i2, int i3, int i4);
``name``
The ``name`` argument is symbol name to find and call.
.. index:: rtl trace
.. _rtl-trace:
``trace``:
Clear or set trace flags. The trace flags provide details trace
information from the link editor and can aid debugging. Note, some
options can produce a large volume or output.
The command is:
.. code-block:: none
rtl trace [-l] [-h] [set/clear] flags...
The options are:
``-l``
List the available flags that can be cleared or set.
``-?``
A ``trace`` command specific help
The flags are:
- ``all``
- ``detail``
- ``warning``
- ``load``
- ``unload``
- ``section``
- ``symbol``
- ``reloc``
- ``global-sym``
- ``load-sect``
- ``allocator``
- ``unresolved``
- ``cache``
- ``archives``
- ``archive-syms``
- ``dependency``
- ``bit-alloc``
EXIT STATUS:
This command returns 0 to indicate success else it returns 1.
NOTES:
- Using this command may initialise the RTL manager if has not been used
and initialised before now.
- A base kernel image symbol file has to be present for base kernel symbols
to be viewed and searched.
EXAMPLES:
The following examples can be used with the testsuite's ``dl10`` test.
Attempt to load an object file that not exist then load an object file that
exists:
.. code-block:: none
SHLL [/] # rtl obj load /foo.o
error: load: /foo.o: file not found
SHLL [/] $ rtl obj load /dl10-o1.o
List the object files:
.. code-block:: none
SHLL [/] # rtl list
/dl10-o1.o
/libdl10_1.a:dl10-o2.o
/libdl10_2.a:dl10-o5.o
/libdl10_2.a:dl10-o3.o
/libdl10_1.a:dl10-o4.o
The list shows the referenced archive object files that have been
loaded. Show the details for the library object file ``dl10-o2.o``:
.. code-block:: none
SHLL [/] # rtl list -l dl10-o4.o
/libdl10_1.a:dl10-o4.o
unresolved : 0
users : 0
references : 1
symbols : 7
symbol memory : 250
The object file has one reference, 7 symbols and uses 250 bytes of
memory. List the symbols:
.. code-block:: none
SHLL [/] # rtl list -s dl10-o4.o
/libdl10_1.a:dl10-o4.o
rtems_main_o4 = 0x20de818
dl04_unresolv_1 = 0x20dead0
dl04_unresolv_2 = 0x20dead4
dl04_unresolv_3 = 0x20dead8
dl04_unresolv_4 = 0x20deadc
dl04_unresolv_5 = 0x20deaa0
dl04_unresolv_6 = 0x20deac0
The dependents of a group of object files can be listed using a regular
expression:
.. code-block:: none
SHLL [/] # rtl list -d dl10-o[234].o
/libdl10_1.a:dl10-o2.o
dependencies : dl10-o3.o
/libdl10_2.a:dl10-o3.o
dependencies : dl10-o4.o
: dl10-o5.o
/libdl10_1.a:dl10-o4.o
dependencies : dl10-o5.o
A number of flags can be selected at once:
.. code-block:: none
SHLL [/] # rtl list -lmsd dl10-o1.o
/dl10-o1.o
exec size : 1086
text base : 0x20dbec0 (352)
const base : 0x20dc028 (452)
data base : 0x20dc208 (12)
bss base : 0x20dc220 (266)
unresolved : 0
users : 1
references : 0
symbols : 9
symbol memory : 281
dl01_func1 = 0x20dbec0
rtems_main_o1 = 0x20dbec8
dl01_bss1 = 0x20dc220
dl01_bss2 = 0x20dc224
dl01_bss3 = 0x20dc2a0
dl01_data1 = 0x20dc20c
dl01_data2 = 0x20dc208
dl01_const1 = 0x20dc1e8
dl01_const2 = 0x20dc1e4
dependencies : dl10-o2.o
List all symbols that contain ``main``:
.. code-block:: none
SHLL [/] # rtl sym main
/dl10-o1.o
rtems_main_o1 = 0x20dbec8
/libdl10_1.a:dl10-o2.o
rtems_main_o2 = 0x20dd1a0
/libdl10_2.a:dl10-o5.o
rtems_main_o5 = 0x20df280
/libdl10_2.a:dl10-o3.o
rtems_main_o3 = 0x20ddc40
/libdl10_1.a:dl10-o4.o
rtems_main_o4 = 0x20de818
Include the base kernel image in the search:
.. code-block:: none
SHLL [/] # rtl sym -b main
rtems-kernel
rtems_shell_main_cp = 0x2015e9c
rtems_shell_main_loop = 0x201c2bc
rtems_shell_main_monitor = 0x203f070
rtems_shell_main_mv = 0x201a11c
rtems_shell_main_rm = 0x201ad38
/dl10-o1.o
rtems_main_o1 = 0x20dbec8
/libdl10_1.a:dl10-o2.o
rtems_main_o2 = 0x20dd1a0
/libdl10_2.a:dl10-o5.o
rtems_main_o5 = 0x20df280
/libdl10_2.a:dl10-o3.o
rtems_main_o3 = 0x20ddc40
/libdl10_1.a:dl10-o4.o
rtems_main_o4 = 0x20de818
The filter is a regular expression:
.. code-block:: none
SHLL [/] # rtl sym -b ^rtems_task
rtems-kernel
rtems_task_create = 0x2008934
rtems_task_delete = 0x20386b8
rtems_task_exit = 0x2008a98
rtems_task_ident = 0x2038738
rtems_task_iterate = 0x2038798
rtems_task_self = 0x20387b8
rtems_task_set_priority = 0x20387c4
rtems_task_start = 0x2008b7c
rtems_task_wake_after = 0x2008bd0
The search can be limited to a selection of object files:
.. code-block:: none
SHLL [/] # rtl sym -o dl10-o[12].o dl01_b
/dl10-o1.o
dl01_bss1 = 0x20dc220
dl01_bss2 = 0x20dc224
dl01_bss3 = 0x20dc2a0
SHLL [/] # rtl sym -o dl10-o[12].o dl0[12]_b
/dl10-o1.o
dl01_bss1 = 0x20dc220
dl01_bss2 = 0x20dc224
dl01_bss3 = 0x20dc2a0
/libdl10_1.a:dl10-o2.o
dl02_bss1 = 0x20dd400
dl02_bss2 = 0x20dd404
dl02_bss3 = 0x20dd420
List the archives known to the link editor:
.. code-block:: none
SHLL [/] # rtl ar
/libdl10_1.a
/libdl10_2.a
A long listing of the archives provides the link editor details:
.. code-block:: none
SHLL [/] # rtl ar -l
/libdl10_1.a:
size : 37132
symbols : 13
refs : 0
flags : 0
/libdl10_2.a:
size : 53050
symbols : 8
refs : 0
flags : 0
.. index:: list archive symbols
List the symbols an archive provides using the ``-s`` option:
.. code-block:: none
SHLL [/] # rtl ar -s libdl10_1.a
/libdl10_1.a:
symbols : dl02_bss1
dl02_bss2
dl02_bss3
dl02_data1
dl02_data2
dl04_unresolv_1
dl04_unresolv_2
dl04_unresolv_3
dl04_unresolv_4
dl04_unresolv_5
dl04_unresolv_6
rtems_main_o2
rtems_main_o4
.. index:: duplicate symbols
List the duplicate symbols in the archives using the ``-d`` option:
.. code-block:: none
SHLL [/] # rtl ar -d
/libdl10_1.a:
dups :
/libdl10_2.a:
dups : rtems_main_o5 (/libdl10_2.a)
The link editor will list the first archive if finds that has the duplicate
symbol.
Call the symbol ``rtems_main_o4`` with no options:
.. code-block:: none
SHLL [/] # rtl call rtems_main_o4
dlo4: module: testsuites/libtests/dl10/dl-o4.c
dlo4: dl04_unresolv_1: 4: 0x20dee68: 0
dlo4: dl04_unresolv_2: 4: 0x20dee6c: %f
dlo4: dl04_unresolv_3: 1: 0x20dee70: 00
dlo4: dl04_unresolv_4: 4: 0x20dee74: 0
dlo4: dl04_unresolv_5: 4: 0x20dee38: 4
dlo4: dl04_unresolv_6: 4: 0x20dee58: dl-O4
dlo5: module: testsuites/libtests/dl10/dl-o5.c
dlo5: dl05_unresolv_1: 8: 0x20df860: 0
dlo5: dl05_unresolv_2: 2: 0x20df868: 0
dlo5: dl05_unresolv_3: 4: 0x20df86c: 0
dlo5: dl05_unresolv_4: 1: 0x20df870: 0
dlo5: dl05_unresolv_5: 8: 0x20df878: 0
Call a symbol in a data section of an object file:
.. code-block:: none
SHLL [/] # rtl call dl04_unresolv_3
error: symbol not in obj text: dl04_unresolv_3
Call the symbol ``rtems_main_o5`` with a single string:
.. code-block:: none
SHLL [/] # rtl call -s rtems_main_o5 arg1 arg2 "arg3 and still arg3" arg4
dlo5: module: testsuites/libtests/dl10/dl-o5.c
dlo5: dl05_unresolv_1: 8: 0x20df860: 0
dlo5: dl05_unresolv_2: 2: 0x20df868: 0
dlo5: dl05_unresolv_3: 4: 0x20df86c: 0
dlo5: dl05_unresolv_4: 1: 0x20df870: 0
dlo5: dl05_unresolv_5: 8: 0x20df878: 0
Note, the call does not have any argument and the strin passed is
ignored.
Call the symbol ``rtems_main_o5`` with three integer arguments:
.. code-block:: none
SHLL [/] # rtl call -i rtems_main_o5 1 22 333
dlo5: module: testsuites/libtests/dl10/dl-o5.c
dlo5: dl05_unresolv_1: 8: 0x20df860: 0
dlo5: dl05_unresolv_2: 2: 0x20df868: 0
dlo5: dl05_unresolv_3: 4: 0x20df86c: 0
dlo5: dl05_unresolv_4: 1: 0x20df870: 0
dlo5: dl05_unresolv_5: 8: 0x20df878: 0
.. index:: rtems_rtl_shell_command
CONFIGURATION:
This command is not included in the default shell command set. The command
needs to be added with the shell's ``rtems_shell_add_cmd``.
.. code-block:: c
#include <rtems/rtl/rtl-shell.h>
#include <rtems/shell.h>
rtems_shell_init_environment ();
if (rtems_shell_add_cmd ("rtl",
"rtl",
"rtl -?",
rtems_rtl_shell_command) == NULL)
printf("error: command add failed\n");
PROGRAMMING INFORMATION:
The ``rtl`` commanf is implemented by a C language function which has the
following prototype:
.. code-block:: c
int rtems_rtl_shell_command(
int argc,
char **argv
);
The sub-command parts of the ``rtl`` command can be called directly. These
calls all use the RTEMS Printer interface and as a result can be redirected
and captured.
.. index:: rtems_rtl_shell_list
``list``
The RTL list command.
.. code-block:: c
#include <rtems/rtl/rtl-shell.h>
int rtems_rtl_shell_list (
const rtems_printer* printer,
int argc,
char* argv[]
);
.. index:: rtems_rtl_shell_object
``sym``
The RTL symbol command.
.. code-block:: c
#include <rtems/rtl/rtl-shell.h>
int rtems_rtl_shell_sym (
const rtems_printer* printer,
int argc,
char* argv[]
);
.. index:: rtems_rtl_shell_object
``sym``
The RTL object command.
.. code-block:: c
#include <rtems/rtl/rtl-shell.h>
int rtems_rtl_shell_object (
const rtems_printer* printer,
int argc,
char* argv[]
);
.. index:: rtems_rtl_shell_archive
``ar``
The RTL object command.
.. code-block:: c
#include <rtems/rtl/rtl-archive.h>
int rtems_rtl_shell_archive (
const rtems_printer* printer,
int argc,
char* argv[]
);
.. index:: rtems_rtl_shell_call
``call``
The RTL object command.
.. code-block:: c
#include <rtems/rtl/rtl-archive.h>
int rtems_rtl_shell_call (
const rtems_printer* printer,
int argc,
char* argv[]
);
