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.. SPDX-License-Identifier: GPL-2.0+
.. Copyright 2022, Heinrich Schuchardt <xypron.glpk@gmx.de>
source command
==============
Synopsis
--------
::
source [<addr>][:[<image>]|#[<config>]]
Description
-----------
The *source* command is used to execute a script file from memory.
Two formats for script files exist:
* legacy U-Boot image format
* Flat Image Tree (FIT)
The benefit of the FIT images is that they can be signed and verifed as
decribed in :download:`signature.txt <../../uImage.FIT/signature.txt>`.
Both formats can be created with the mkimage tool.
addr
location of the script file in memory, defaults to CONFIG_SYS_LOAD_ADDR.
image
name of an image in a FIT file
config
name of a configuration in a FIT file. A hash sign following white space
starts a comment. Hence, if no *addr* is specified, the hash sign has to be
escaped with a backslash or the argument must be quoted.
If both *image* and *config* are omitted, the default configuration is used, or
if no configuration is defined, the default image.
Examples
--------
FIT image
'''''''''
For creating a FIT image an image tree source file (\*.its) is needed. Here is
an example (source.its).
.. code-block::
/dts-v1/;
/ {
description = "FIT image to test the source command";
#address-cells = <1>;
images {
default = "script-1";
script-1 {
data = "echo 1";
type = "script";
compression = "none";
};
script-2 {
data = "echo 2";
type = "script";
compression = "none";
};
};
configurations {
default = "conf-2";
conf-1 {
script = "script-1";
};
conf-2 {
script = "script-2";
};
};
};
The FIT image file (boot.itb) is created with:
.. code-block:: bash
mkimage -f source.its boot.itb
In U-Boot the script can be loaded and execute like this
.. code-block::
=> load host 0:1 $loadaddr boot.itb
1552 bytes read in 0 ms
=> source $loadaddr#conf-1
## Executing script at 00000000
1
=> source $loadaddr#conf-2
## Executing script at 00000000
2
=> source $loadaddr:script-1
## Executing script at 00000000
1
=> source $loadaddr:script-2
## Executing script at 00000000
2
=> source $loadaddr
## Executing script at 00000000
2
=> source \#conf-1
## Executing script at 00000000
1
=> source '#conf-1'
## Executing script at 00000000
1
=> source ':script-1'
## Executing script at 00000000
1
=> source
## Executing script at 00000000
2
=>
Instead of specifying command line instructions directly in the *data* property
of the image tree source file another file can be included. Here is a minimal
example which encapsulates the file boot.txt:
.. code-block::
/dts-v1/;
/ {
description = "";
images {
script {
data = /incbin/("./boot.txt");
type = "script";
};
};
};
Legacy U-Boot image
'''''''''''''''''''
A script file using the legacy U-Boot image file format can be created based on
a text file. Let's use this example text file (boot.txt):
.. code-block:: bash
echo Hello from a script
echo -------------------
The boot scripts (boot.scr) is created with:
.. code-block:: bash
mkimage -T script -n 'Test script' -d boot.txt boot.scr
The script can be execute in U-boot like this:
.. code-block::
=> load host 0:1 $loadaddr boot.scr
122 bytes read in 0 ms
=> source $loadaddr
## Executing script at 00000000
Hello from a script
-------------------
=> source
## Executing script at 00000000
Hello from a script
-------------------
=>
Configuration
-------------
The source command is only available if CONFIG_CMD_SOURCE=y.
The FIT image file format requires CONFIG_FIT=y.#
The legacy U-Boot image file format requires CONFIG_LEGACY_IMAGE_FORMAT=y.
On hardened systems support for the legacy U-Boot image format should be
disabled as these images cannot be signed and verified.
Return value
------------
If the scripts is executed successfully, the return value $? is 0 (true).
Otherwise it is 1 (false).
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