I am running ubuntu 13.10 on linux kernel version 3.11.0-12.I have to add a system call in this but i am facing a problem. The very first step says that I have to change my current working directory to kernel directory.
I used the command " cd linux-3.11.0-12 " but it is showing that no such file or directory exists. Please tell me where am i going wrong and how do I correct this mistake.
Wait, you want to add a system call to the Linux kernel, but you don't know how to reach the source code? Are you sure you are able to modify, configure, build, install and boot the Linux kernel?
Assuming yes, you need to get the source code of Linux first (for example, by cloning https://github.com/torvalds/linux or just downloading the version you are interested in), extract it somewhere and then cd to the path where you extracted it. Then you can begin modifying to your heart's content.
Perhaps this blog post could help you.
To get the source of the installed kernel on ubuntu, you can use the command [for ubuntu 13.04+ ]
apt-get source linux-image-`uname -r`
and should be typically be placed under /usr/src
Reference:
[1] https://help.ubuntu.com/community/Kernel/Compile
[2] https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel
Related
I have a Yocto build for i.mx6 and I want to modify its Kernel. I figured that if I copy Kernel source outside the Yocto project and make my modifications without dealing with patches, I can speed things up significantly. But the thing is, the Kernel source I have to use is already patched and I want to fetch and continue working from there. I will work on the already-patched source files and re-arranging them is a painful process.
For starting point, my patches work fine, and I can get a working image using bitbake fsl-image-multimedia-full command. The Kernel source I want to use is created after this process.
I have tried copying the source under ..../tmp/work-shared/imx6qsabresd/kernel-source. Although make zImage and make modules finished without any trouble, manual building was not successful with an error in a dtsi file (Unable to parse...). Of course, I have checked the file and there was no syntax error.
Also, I checked the kernel source files I copied and it seems that the patches are successfully implemented.
Am I doing something wrong with the patches? With my manual build routine, I can build unpatched kernel source with no errors. I am sure that there are experienced Yocto users here that have their own workarounds to make this process shorter. So, any help is appreciated. Thanks in advance.
You can also edit files in tmp/work-shared/<machine>/kernel-source then compile modified kernel with bitbake -C compile virtual/kernel
My favorite method of doing kernel development in a Yocto project is to create an SDK and build the kernel outside of the Yocto system. This allows more rapid builds because make will only build new changes, whereas a kernel build within Yocto always starts from scratch.
Here are some of my notes on compiling the Linux kernel outside of the Yocto system. The exact paths for this will depend on your exact configuration and software versions. In your case, IMAGE_NAME=fsl-image-multimedia-full
Run bitbake -c populate_sdk ${IMAGE_NAME}. You will get a
self-extracting and self-installing shell script.
Run the shell script (for me it was
tmp/deploy/sdk/${NAME}-glibc-i686-${IMAGE_NAME}-cortexa9hf-neon-toolchain-1.0.0.sh),
and agree to the default SDK location (for me it was
usr/local/oecore-i686).
Source the scripts generated by the install script. I use the
following helper script to load the SDK so I don't have to keep
track of the paths involved. You need to source this in each time
you want to use the SDK.
enable_sdk.sh:
#!/bin/bash
if [[ "$0" = "$BASH_SOURCE" ]]
then
echo "Error: you must source this script."
exit 1
fi
source /usr/local/oecore-i686/environment-setup-corei7-32-${NAME}-linux
source /usr/local/oecore-i686/environment-setup-cortexa9hf-neon-${NAME}-linux-gnueabi
Copy the defconfig file from your Yocto directory to your kernel
directory (checked out somewhere outside of the Yocto tree) as
.config.
Run make oldconfig in your kernel directory so that the Linux
kernel build system picks up the existing .config.
Note: you may have to answer questions about config options that
are not set in the .config file.
Note: running make menuconfig will fail when the SDK is enabled,
because the SDK does not have the ncurses libraries set up
correctly. For this command, run it in a new terminal that has not
enabled the SDK so that it uses the local ncurses-dev packages you
have installed.
Run make -jN to build the kernel.
To run the new kernel, copy the zImage and ${NAME}.dtb files to
your NFS/TFTP share or boot device. I use another script to speed
up the process.
update_kernel.sh:
#!/bin/bash
set -x
sudo cp /path-to-linux-source/arch/arm/boot/dts/${NAME}.dtb /srv/nfs/${DEVICE}/boot/
sudo cp /path-to-linux-source/arch/arm/boot/zImage /srv/nfs/${DEVICE}/boot/
set +x
You can also point Yocto to your local Linux repo in your .bb
file. This is useful for making sure your kernel changes still
build correctly within Yocto.
SRC_URI = "git:///path-to-linux-source/.git/;branch=${KBRANCH};protocol=file"
UPDATE: Over a year later, I realize that I completely missed the question about broken patches. Without more information, I can't be sure what went wrong copying the kernel source from Yocto to an external build. I'd suggest opening a Bitbake devshell for the kernel and doing a diff with the external directory after manually applying patches to see what went wrong, or just copy the source from inside the devshell to your external directory.
https://www.yoctoproject.org/docs/1.4.2/dev-manual/dev-manual.html#platdev-appdev-devshell
When debugging certain commands or even when just editing packages, devshell can be a useful tool. When you invoke devshell, source files are extracted into your working directory and patches are applied.
Since it can't parse it, there seems to be a problem with patch. How do you patch the device tree? Are you patching it in the .bb file?
If so, check your patch for possible syntax errors, it's very easy to overlook the syntax errors in device tree. You can remove the patch and do it manually from bitbake -c devshell <kernel-name>
If not, please try to do it there and check again. Please share results if any of these helps you.
I need some help to install the ABySS assembler on PuTTY (virtual Linux) without root permission (as it takes a long time going via IT department etc.).
To be honest I've no idea where to start from, so I'll be very appreciated for step-by-step guide if that is not too much to ask.
Thanks in advance.
If you are referring to the software here, then it should be sufficient to follow the instructions here. Specifically, you should take note of the part labelled To install ABySS in a specified directory:, and specify a directory in your home directory that you have write access to. For example, I might:
mkdir ~/abyss
./configure --prefix=$HOME/abyss
make
make install
Note that I have removed sudo from before make install, so that you are trying to run the installation as a user rather than root. make install will put the software wherever you specified with --prefix.
However, this all depends upon the source code for any libraries upon which ABySS depends existing on your system as well. I expect you will fail at the ./configure step because some library is missing. In this case download the source code for those libraries and tell configure where you have put them (in your home directory), following the example given for Boost on that same page.
I'm a beginner at Debian, and GNU/linux in general and I was following a tutorial to create a cross compiler, when I stumbled upon the message
/usr/bin/fakeroot: line 178: /debian/rules/: No such file or directory
when running the following command
TARGET="alpha-dec-osf4" fakeroot debian/rules binary-cross
or even
fakeroot /debian/rules/ clean
I'm trying to find a manual or guide to learn about debian/rules, but I even have problems finding something for beginners.
Does anybody know what I'm doing wrong? I'm using Debian GNU/Linux 7.5 (wheezy)
Thank you very much in advance
EDIT: I tried these commands to compile a binutils 2.17, in order to make a cross compiler that would output Alpha OSF/1 binaries on x86 systems. I downloaded binutils from the GNU webpage, so perhaps this was my main mistake, as #Sigi explained that it should be a debian package.
You must not use /debian/rules, but instead debian/rules (note the missing slash at the beginning). If you start a path to a file with a slash (/), the system will start the search in the root directory of your filesystem (this is the top-most directory on any Unix system). On the other hand, if your path does not begin with a slash, the search will always be relative to your current directory. The latter is what applies to invoking debian/rules.
The command is supposed to be executed inside an extracted Debian source package. Check if ls debian/rules will list a file, otherwise you are in the wrong directory.
Regarding a guide for beginners or anything: Debian package building, let alone the creating or modification of Debian packages is decidedly not a beginner's topic. You should first get a solid foundational knowledge in Linux administration before getting your hands dirty in that area.
I want to add some debug info or printf in the random.c in order to look deeply into the Linux random number generator. The entropy in /dev/random and /dev/urandom are both generated by random.c. My questions are:
1. Where I can find the random.c file in Linux 2.6.32?
2. What is the best way to add my modification of random source code into the kernel? Is it OK to just compile random.c and load it as loadable kernel module? Or do I have to recompile and install the kernel to make the new random.c with debug msg somehow take effect? The key point is to make sure that only one copy of random number generator is running in the kernel.
Thank you. Any kind of suggestion is highly appreciated.
random.c is linked directly into the kernel, it isn't built as a module, so you can't just recompile it alone and load it into your kernel, you need to recompile the whole new kernel.
To build the kernel, make sure you have the usual development tools installed: gcc, GNU make, etc. Some distros provide a "build-essentials" or "Development Tools" or similar metapackage that include all of the usual development tools for building the core system packages.
How you build your kernel depends on whether you have any distribution specific patches that are needed to use your system, or if you want to ensure that you use your distro's packaging system to install the kernel. If so, you should probably follow your distro's instructions for building the kernel. For example, Ubuntu's instructions, Arch's instructioins, Fedora's instructions, CentOS instructions (likely similar on RHEL 6, Red Hat doesn't provide documentation as they don't support building custom kernels), SuSE instructions.
Otherwise, if you don't mind configuring and installing your kernel manually, you can do it by hand. The following instructions should cover most distros reasonable well, but be sure to check your distro docs in case there are any distro-specific gotchas.
Download the appropriate tarball from kernel.org and decompress it somewhere. Or if you prefer, check it out using Git. Since you reference 2.6.32, I've included the latest version of 2.6.32 in the below instructions.
$ curl -O https://www.kernel.org/pub/linux/kernel/v2.6/longterm/v2.6.32/linux-2.6.32.61.tar.xz
$ xzcat linux-2.6.32.61.tar.xz | tar xvf -
$ cd linux-2.6.32.61
# or...
$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
$ cd linux
$ git checkout -b my-branch v2.6.32.61
Now you need to do to configure it, build it, and install it. Greg Kroah-Hartmann, a leading kernel developer and stable kernel maintainer, has a free book on the subject. I'd recommend reading his book, but if you want a quick rundown, I'll summarize the highlights.
There are several ways to configure it. A good way to start is to just copy your current config in, and then run make menuconfig or make xcconfig to get a curses or graphical kernel configuration utility that allows you to easily browse and choose the right options (as there may be new options in the new kernel that you are building). Many distros install the config for a given kernel in /boot/config or /boot/config-version corresponding to the kernel version. Copy that into your source tree as .config, and then run make menuconfig or make xconfig:
$ cp /boot/config .config
$ make xconfig
After configuring it, I'd recommend adding something to the EXTRAVERSION definition in the Makefile. The contents of that are tacked on to the version, to help distinguish your modified kernel from the upstream one. I'd recommend setting it to help keep track of which is your modified kernel.
Once it's configured, just build it like anything else. I recommend using -j to run a parallel build if you have multiple cores.
$ make -j8
Now it's built, and you can install it. On most systems, the following works; if not, check out Greg's book or check your distro's documentation:
$ sudo make modules_install
$ sudo make install
And finally you have to add it to your bootloader (on some systems, make install may do this, on some it may not). Depending on whether you use Lilo, Grub, or Grub2, you may need to edit /etc/lilo.conf (followed by running sudo lilo to install the changes), /boot/grub/menu.lst, or /boot/grub/custom.cfg (followed by sudo grub-mkconfig -o /boot/grub/grub.cfg to install the changes). See the relevant documentation for the given bootloader for more details. Generally you want to copy an existing entry and duplicate it, updating it to point to your new kernel. Make sure you leave the existing entries, so you will be able to boot back into your old kernel if this doesn't work.
Now reboot, select your new kernel, and hope your system boots. Woo! You've built your own kernel.
Now that you've made sure you can do that successfully without modifications, you can make your change. You are going to want to modify drivers/char/random.c. To print out debugging statements, use printk(). It works mostly like printf(), though it's not exactly the same so check out the documentation before using it. After you modify, rebuild, and reinstall your new kernel, and reboot into it, you can see the messages printed out with printk() statements using the dmesg command.
For more information, check out Greg's book that I linked to above, the kernel README, and HOWTO, browse around the kernel's Documentation directory, and various other docs.
If you look at the Makefile for it, char driver is not meant to be compiled as a module (random.o is included as obj-y in drivers/char/Makefile).
You can read more about how to kbuild (kernel build) system works from: https://www.kernel.org/doc/Documentation/kbuild/makefiles.txt
Particularly section --- 3.1 Goal definitions touches this topic.
Generally you can search for files in kernel sources from source cross references (called LXR's). One is for example provided in http://lxr.free-electrons.com/
Indeed, you can add your modifications to the drivers/char/random.c, and recompile the char driver. After that you will have to rebuild the kernel, so that it will link also your new random.o to the kernel. And then you will have to boot that kernel, that process will depend on your distribution.
Most distributions have good/decent instructions around how to recompile/boot your own kernel.
I am trying to install mod_java on ubuntu.
I have installed the latest java(1.6).
I have configured freeswitch with mod_java module enabled in module.conf.xml
then when i run the make file, it says:
freeswitch_java.h:5:17: error: jni.h: No such file or directory
I have searched through the java installtion folders, but did not find any include folder or jni.h.
Can anyone help, what is being the problem here.
Thanks for reading this question.
I had the same problem. The solution was to run configure with the option --with-java:
./configure --with-java=/usr/lib/jvm/java-1.6.0-openjdk/include/
I don't know if it makes any difference but I added mod_java after building freeswitch without it. It was disabled in my initial build in module.conf.xml but afterwards I ran the above command plus:
make mod_java-install
It worked for me on ubuntu with openjdk. Are you using the Sun JDK? Maybe in the version you have dont have the include folder which has the source files. Try installing the other JDK. Or try and see of ther are some other related packages in apt that will get you the include folder.
Type this linux command to locate your jni.h file on your filesystem.
locate jni.h
you should be able to get it somewhere
in /usr/lib/java directory or some other directory
depending upon your java home.
copy paste the jni.h in src/include folder of your freeswitch src.
It will throw you some more errors for different .h files
just copy all of them to your src/include folder.
in latest freeswitch, installing through Makefile, its not possible to configure as the Makefile downloads and installs. Its possible by modifying the Makefile.in file to add the include path
mod_java_la_CPPFLAGS
-I/usr/lib/jvm/default-java/include \