How can I get "HelloWorld - BitBake Style" working on a newer version of Yocto? - yocto

In the book "Embedded Linux Systems with the Yocto Project", Chapter 4 contains a sample called "HelloWorld - BitBake style". I encountered a bunch of problems trying to get the old example working against the "Sumo" release 2.5.
If you're like me, the first error you encountered following the book's instructions was that you copied across bitbake.conf and got:
ERROR: ParseError at /tmp/bbhello/conf/bitbake.conf:749: Could not include required file conf/abi_version.conf
And after copying over abi_version.conf as well, you kept finding more and more cross-connected files that needed to be moved, and then some relative-path errors after that... Is there a better way?

Here's a series of steps which can allow you to bitbake nano based on the book's instructions.
Unless otherwise specified, these samples and instructions are all based on the online copy of the book's code-samples. While convenient for copy-pasting, the online resource is not totally consistent with the printed copy, and contains at least one extra bug.
Initial workspace setup
This guide assumes that you're working with Yocto release 2.5 ("sumo"), installed into /tmp/poky, and that the build environment will go into /tmp/bbhello. If you don't the Poky tools+libraries already, the easiest way is to clone it with:
$ git clone -b sumo git://git.yoctoproject.org/poky.git /tmp/poky
Then you can initialize the workspace with:
$ source /tmp/poky/oe-init-build-env /tmp/bbhello/
If you start a new terminal window, you'll need to repeat the previous command which will get get your shell environment set up again, but it should not replace any of the files created inside the workspace from the first time.
Wiring up the defaults
The oe-init-build-env script should have just created these files for you:
bbhello/conf/local.conf
bbhello/conf/templateconf.cfg
bbhello/conf/bblayers.conf
Keep these, they supersede some of the book-instructions, meaning that you should not create or have the files:
bbhello/classes/base.bbclass
bbhello/conf/bitbake.conf
Similarly, do not overwrite bbhello/conf/bblayers.conf with the book's sample. Instead, edit it to add a single line pointing to your own meta-hello folder, ex:
BBLAYERS ?= " \
${TOPDIR}/meta-hello \
/tmp/poky/meta \
/tmp/poky/meta-poky \
/tmp/poky/meta-yocto-bsp \
"
Creating the layer and recipe
Go ahead and create the following files from the book-samples:
meta-hello/conf/layer.conf
meta-hello/recipes-editor/nano/nano.bb
We'll edit these files gradually as we hit errors.
Can't find recipe error
The error:
ERROR: BBFILE_PATTERN_hello not defined
It is caused by the book-website's bbhello/meta-hello/conf/layer.conf being internally inconsistent. It uses the collection-name "hello" but on the next two lines uses _test suffixes. Just change them to _hello to match:
# Set layer search pattern and priority
BBFILE_COLLECTIONS += "hello"
BBFILE_PATTERN_hello := "^${LAYERDIR}/"
BBFILE_PRIORITY_hello = "5"
Interestingly, this error is not present in the printed copy of the book.
No license error
The error:
ERROR: /tmp/bbhello/meta-hello/recipes-editor/nano/nano.bb: This recipe does not have the LICENSE field set (nano)
ERROR: Failed to parse recipe: /tmp/bbhello/meta-hello/recipes-editor/nano/nano.bb
Can be fixed by adding a license setting with one of the values that bitbake recognizes. In this case, add a line onto nano.bb of:
LICENSE="GPLv3"
Recipe parse error
ERROR: ExpansionError during parsing /tmp/bbhello/meta-hello/recipes-editor/nano/nano.bb
[...]
bb.data_smart.ExpansionError: Failure expanding variable PV_MAJOR, expression was ${#bb.data.getVar('PV',d,1).split('.')[0]} which triggered exception AttributeError: module 'bb.data' has no attribute 'getVar'
This is fixed by updating the special python commands being used in the recipe, because #bb.data was deprecated and is now removed. Instead, replace it with #d, ex:
PV_MAJOR = "${#d.getVar('PV',d,1).split('.')[0]}"
PV_MINOR = "${#d.getVar('PV',d,1).split('.')[1]}"
License checksum failure
ERROR: nano-2.2.6-r0 do_populate_lic: QA Issue: nano: Recipe file fetches files and does not have license file information (LIC_FILES_CHKSUM) [license-checksum]
This can be fixed by adding a directive to the recipe telling it what license-info-containing file to grab, and what checksum we expect it to have.
We can follow the way the recipe generates the SRC_URI, and modify it slightly to point at the COPYING file in the same web-directory. Add this line to nano.bb:
LIC_FILES_CHKSUM = "${SITE}/v${PV_MAJOR}.${PV_MINOR}/COPYING;md5=f27defe1e96c2e1ecd4e0c9be8967949"
The MD5 checksum in this case came from manually downloading and inspecting the matching file.
Done!
Now bitbake nano ought to work, and when it is complete you should see it built nano:
/tmp/bbhello $ find ./tmp/deploy/ -name "*nano*.rpm*"
./tmp/deploy/rpm/i586/nano-dbg-2.2.6-r0.i586.rpm
./tmp/deploy/rpm/i586/nano-dev-2.2.6-r0.i586.rpm

I have recently worked on that hands-on hello world project. As far as I am concerned, I think that the source code in the book contains some bugs. Below there is a list of suggested fixes:
Inheriting native class
In fact, when you build with bitbake that you got from poky, it builds only for the target, unless you mention in your recipe that you are building for the host machine (native). You can do the latter by adding this line at the end of your recipe:
inherit native
Adding license information
It is worth mentioning that the variable LICENSE is important to be set in any recipe, otherwise bitbake rises an error. In our case, we try to build the version 2.2.6 of the nano editor, its current license is GPLv3, hence it should be mentioned as follow:
LICENSE = "GPLv3"
Using os.system calls
As the book states, you cannot dereference metadata directly from a python function. Which means it is mandatory to access metadata through the d dictionary. Bellow, there is a suggestion for the do_unpack python function, you can use its concept to code the next tasks (do_configure, do_compile):
python do_unpack() {
workdir = d.getVar("WORKDIR", True)
dl_dir = d.getVar("DL_DIR", True)
p = d.getVar("P", True)
tarball_name = os.path.join(dl_dir, p+".tar.gz")
bb.plain("Unpacking tarball")
os.system("tar -x -C " + workdir + " -f " + tarball_name)
bb.plain("tarball unpacked successfully")
}
Launching the nano editor
After successfully building your nano editor package, you can find your nano executable in the following directory in case you are using Ubuntu (arch x86_64):
./tmp/work/x86_64-linux/nano/2.2.6-r0/src/nano
Should you have any comments or questions, Don't hesitate !

Related

Yocto rust recipe also produces -native output that needs packaging

I tried this approach on hardknott but I couldn't get it to work recipe also produces -native output that needs packaging
It is a rust recipe that generates an x86_64 app which I would like to package the right way in sdk, so that it can be used.
I can separate the main package to -native-bin, and I see it in the recipe-sysroot, but I can't get it to populate the recipe-sysroot of the workdir of the file when building the -native-helper recipe. And I suspect the reason is that I get an error that the main recipe for x86_64 can't be found?
ERROR: Manifest xxxxxx.populate_sysroot not found in vs_imx8mp cortexa53 armv8a-crc armv8a aarch64 allarch x86_64_x86_64-nativesdk (variant '')?
So any helpful information would be appreciated!
Hacked like this:
Recipe.bb:
do_install_append() {
# Set permision without run flag so that it doesn't fail on checks
chmod 644 ${D}/usr/bin/#RECIPE#-compiler
}
# #RECIPE# generates a compiler during the target generation step
#separate this to the -native-bin package, and skip the ARCH checks
#also in the image file for stations_sdk move the app to right dir and add execute flag
PACKAGES_prepend = "${PN}-native-bin "
PROVIDES_prepend = "${PN}-native-bin "
INSANE_SKIP_${PN}-native-bin = "arch"
FILES_${PN}-native-bin = "/usr/bin/#RECIPE#-compiler"
SYSROOT_DIRS += "/"
Image.bb:
# #RECIPE# produces a compiler that is produced as a part of the target generation
#so we use the recipe and hack it to supply the -compiler as part of the
#host binaries
TOOLCHAIN_TARGET_TASK_append = " #RECIPE#-native-bin"
do_fix_#RECIPE#() {
mv ${SDK_OUTPUT}/${SDKTARGETSYSROOT}/usr/bin/#RECIPE#-compiler ${SDK_OUTPUT}/${SDKPATHNATIVE}/usr/bin/#RECIPE#-compiler
chmod 755 ${SDK_OUTPUT}/${SDKPATHNATIVE}/usr/bin/#RECIPE#-compiler
}
SDK_POSTPROCESS_COMMAND_prepend = "do_fix_#RECIPE#; "
This produces at the end the binary in the right directory

"failed to load any lstm-specific dictionaries for lang " tesseract 4.1

I tried to train the tesseract 4.1 using OCRD project but after training completed I copied the lang.traineddata but getting above error.
The tesseractWiki page is very confusing to understand asking to use combine_lang_model after making lstmf file. So Actually I have the lstmf file. I created these file by using tif/box pair.
Please help me for further step.
Related discussions:Failed to load any lstm-specific dictionaries for lang xxx
Suppose your training folder like this:
OCRD/makefile
OCRD/data/foo-ground-truth.
You could try as following steps:
Find the WORDLIST_FILE/NUMBERS_FILE/PUNC_FILE in the makefile, and change them to:
WORDLIST_FILE := data/$(MODEL_NAME).wordlist
NUMBERS_FILE := data/$(MODEL_NAME).numbers
PUNC_FILE := data/$(MODEL_NAME).punc
Suppose your base traineddata is eng.traineddata.
2.1 Download the .wordlist/.numbers/.punc files from the langdata_lstm.
2.2 Place them in OCRD/data
2.3 if the MODEL_NAME = foo, rename them as: foo.wordlist, foo.numbers, foo.punc
if you don't have the base traineddata, you could try this too. But if your base traineddata is afr, you should download the files from langdata_lstm/afr.
make training again
The cause of this error:
In OCRD, the default path of the above three files is $ (OUTPUT_DIR) = data / $ (MODEL_NAME), and all files in this path are automatically generated during the training process.
If the variable START_MODEL is not assigned, the makefile will not generate any related files under this path;
If the variable START_MODEL has been assigned, the foo.lstm-number-dawg、foo.lstm-punc-dawg、foo.lstm-word-dawg and so on will be produced in data / $ (MODEL_NAME). But they are not the right one. So there may be a bug in OCRD.

Yocto find the recipe or class that defines a task

I am a yocto noob, trying to decipher how the device tree is built from a Xilinx hardware definition (.hdf) file. But my question is more general.
Is there a yocto way to find the source of task?
Given a task name is it possible to find where the tasks source code lives? (presumably in a recipe or class)
As an example, where is the source for the Python task do_create_yaml which is called by recipes in the meta-xilinx-bsp layer that compile the device tree blob?
bitbake -e device-tree
Will dump the python source for do_create_yaml (amongst the rest of it prodigious output) but how can I find where that is coming from?
Device tree is part of Linux Kernel. In Yocto, this is compiled from KERNEL_DEVICETREE variable value either defined as part of Linux Kernel recipe or machine configuration.
For example, for cubieboard7 as defined here,
KERNEL_DEVICETREE = "s700_cb7_linux.dtb"
instructs the compilation to use this dts file for compilation. This is done by yocto by using various classes.
In our example, we inherit kernel.bbclass which in turn inherits kernel-devicetree.bbclass, in this class (copied from kernel-devicetree.bbclass),
do_compile_append() {
for dtbf in ${KERNEL_DEVICETREE}; do
dtb=`normalize_dtb "$dtbf"`
oe_runmake $dtb
done
}
do_install_append() {
for dtbf in ${KERNEL_DEVICETREE}; do
dtb=`normalize_dtb "$dtbf"`
dtb_ext=${dtb##*.}
dtb_base_name=`basename $dtb .$dtb_ext`
dtb_path=`get_real_dtb_path_in_kernel "$dtb"`
install -m 0644 $dtb_path ${D}/${KERNEL_IMAGEDEST}/$dtb_base_name.$dtb_ext
done
}
do_deploy_append() {
for dtbf in ${KERNEL_DEVICETREE}; do
dtb=`normalize_dtb "$dtbf"`
this appends tasks to compile, install and deploy tasks. So defining KERNEL_DEVICETREE enables the automatic build of dtb.
I found that the datastore contains the filename for tasks as a VarFlag,
from a devpyshell
pydevshell> d.getVarFlags("do_create_yaml")
gives
{'filename': '.....yocto/sources/core/../meta-xilinx-tools/classes/xsctyaml.bbclass', 'lineno': '61', 'func': 1, 'task': 1, 'python': '1', 'deps': ['do_prepare_recipe_sysroot']}
So for the example in my question the active definition for the do_create_yaml task is in xsctyaml.bbclass.

Auditd in Yocto

I'm trying to add auditd to Yocto linux.
I added the selinux layer and it's dependent layers: openembedded-core and meta-virtualization.
I added the layers to bblayers.conf.
I added DISTRO_FEATURES_append = " acl xattr pam selinux"
and PREFERRED_PROVIDER_virtual/refpolicy ?= "refpolicy-mls" to the local.conf file.
After building (by using bitbake core-image-base) and running the qemu, the kauditd process is running, but all user-space tools are not.
The /etc/audit folder is not exist ,non of the audit's config files exists (audit.rules) and no user-space audit process is running.
In the layer's info it is declared - "User space tools for kernel auditing".
What I am missing?
Thanks.
I think I found something that will answer your question: If you know what an example binary or library you expect to be in the target image, you can find what recipe the executable is in, and then add that package to the image.
Start with the name of a binary or library you expect to be in the image and run the following. For me, I am using a CAN bus executable called candump. I wonder what recipe it's in? To find out, I issue:
devtool search candump
Which returns:
can-utils
If nothing is returned, I'd double check your conf/bblayers.conf so that the layer you think it may be in is actually being seen by your build system. If you are unsure, take a look at the link below which points to OpenEmbedded which has a handy search utility for packages.
After you find the recipe, you can then include that recipe into your build.
Here is a good reference in doing what I think you're asking on the OpenEmbedded website:
https://wiki.yoctoproject.org/wiki/Cookbook:Example:Adding_packages_to_your_OS_image
I just added auditd to my system. This is what I did.
First I got the repository checked out.
cd /path/to/yocto
git clone git://git.yoctoproject.org/meta-selinux
cd meta-selinux
# checkout the branch matching the Yocto release you are on
git checkout thud
Then I added auditd to my build.
cd /path/to/build
bitbake-layers add-layer /path/to/yocto/meta-selinux
cat >> conf/local.conf <<'END'
IMAGE_INSTALL_append = " auditd"
END
bitbake my_normal_image_target
Even though the Yocto recipe is called audit, the package name is auditd.
Of course, auditd without selinux is useless but it did attempt to run (journalctl -u auditd) and /etc/audit exists.
FWIW: To get auditd to a point where it reports say, login success/failure, I had to do a few more things. I'm not just adding it to a standard Yocto image, but to a custom image and custom machine. I'm already using systemd so I didn't have to change that (the layer seems to indicate it's required?). My local.conf looked like this.
# enable selinux
DISTRO_FEATURES_append = " acl xattr pam selinux"
# set the policy
PREFERRED_PROVIDER_virtual/refpolicy ?= "refpolicy-mls"
# install selinux packages and auditd
IMAGE_INSTALL_append = " packagegroup-core-selinux auditd"
# tell the kernel to enable selinux (non-enforcing) and audting
APPEND_append = " selinux=1 enforcing=0 audit=1"
I also had to change linux-yocto_selinux.inc to load selinux.cfg later. Probably layer/recipe ordering could have solved this too?
-SRC_URI += "${#bb.utils.contains('DISTRO_FEATURES', 'selinux', 'file://selinux.cfg', '', d)}"
+SRC_URI_append = "${#bb.utils.contains('DISTRO_FEATURES', 'selinux', 'file://selinux.cfg', '', d)}"
With all that in place, I see audit logs in my journal.

Copy all files with given extension to output directory using CMake

I've seen that I can use this command in order to copy a directory using cmake:
file(COPY "myDir" DESTINATION "myDestination")
(from this post)
My problem is that I don't want to copy all of myDir, but only the .h files that are in there. I've tried with
file(COPY "myDir/*.h" DESTINATION "myDestination")
but I obtain the following error:
CMake Error at CMakeLists.txt:23 (file):
file COPY cannot find
"/full/path/to/myDIR/*.h".
How can I filter the files that I want to copy to a destination folder?
I've found the solution by myself:
file(GLOB MY_PUBLIC_HEADERS
"myDir/*.h"
)
file(COPY ${MY_PUBLIC_HEADERS} DESTINATION myDestination)
this also works for me:
install(DIRECTORY "myDir/"
DESTINATION "myDestination"
FILES_MATCHING PATTERN "*.h" )
The alternative approach provided by jepessen does not take into account the fact that sometimes the number of files to be copied is too high. I encountered the issue when doing such thing (more than 110 files)
Due to a limitation on Windows on the number of characters (2047 or 8191) in a single command line, this approach may randomly fail depending on the number of headers that are in the folder. More info here https://support.microsoft.com/en-gb/help/830473/command-prompt-cmd-exe-command-line-string-limitation
Here is my solution:
file(GLOB MY_HEADERS myDir/*.h)
foreach(CurrentHeaderFile IN LISTS MY_HEADERS)
add_custom_command(
TARGET MyTarget PRE_BUILD
COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CurrentHeaderFile} ${myDestination}
COMMENT "Copying header: ${CurrentHeaderFile}")
endforeach()
This works like a charm on MacOS. However, if you have another target that depends on MyTarget and needs to use these headers, you may have some compile errors due to not found includes on Windows. Therefore you may want to prefer the following option that defines an intermediate target.
function (CopyFile ORIGINAL_TARGET FILE_PATH COPY_OUTPUT_DIRECTORY)
# Copy to the disk at build time so that when the header file changes, it is detected by the build system.
set(input ${FILE_PATH})
get_filename_component(file_name ${FILE_PATH} NAME)
set(output ${COPY_OUTPUT_DIRECTORY}/${file_name})
set(copyTarget ${ORIGINAL_TARGET}-${file_name})
add_custom_target(${copyTarget} DEPENDS ${output})
add_dependencies(${ORIGINAL_TARGET} ${copyTarget})
add_custom_command(
DEPENDS ${input}
OUTPUT ${output}
COMMAND ${CMAKE_COMMAND} -E copy_if_different ${input} ${output}
COMMENT "Copying file to ${output}."
)
endfunction ()
foreach(HeaderFile IN LISTS MY_HEADERS)
CopyFile(MyTarget ${HeaderFile} ${myDestination})
endforeach()
The downside indeed is that you end up with multiple target (one per copied file) but they should all end up together (alphabetically) since they start with the same prefix ORIGINAL_TARGET -> "MyTarget"