I need to control some DC motors using PWM. I have been trying to use the bcm2835 library, but I need root access to run my program. I need to avoid this, as this program is part of a ROS package, which gives problems if run as root. I have tried to follow the instructions that appear in the section "Running as root", but I haven't been successful. I have done the following.
First, I have installed libcap2 and libcap-dev and added my user to the kmem group.
sudo apt-get install libcap2 libcap-dev
sudo adduser ubuntu kmem
Then, I have installed the version latest version of bcm2835 library.
wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.67.tar.gz
tar zxvf bcm2835-1.67.tar.gz
cd bcm2835-1.67
./configure
make
sudo make check
sudo make install
After that, I uncommented the #define BCM2835_HAVE_LIBCAP line in bcm2835.h, which I found in /usr/local/include/.
I allowed write access to /dev/mem by members of kmem group.
echo 'SUBSYSTEM=="mem", KERNEL=="mem", GROUP="kmem", MODE="0660"' | sudo tee /etc/udev/rules.d/98-mem.rules
sudo reboot
And finally, I compiled my program (called l298n) and run the following command.
sudo setcap cap_sys_rawio+ep l298n
After doing all this, my program is still not able to provide PWM control unless I run it as root.
Have I done anything wrong? Is there any other way around this? As far as I know, other libraries would run into the same problem, as it depends on the access level of /dev/mem.
I am running Ubuntu 20.04 LTS in a Raspberry Pi 3B+.
What you did wrong:
You edited the wrong bcm2835.h, you need to edit bcm2835.h where ever you unpacked bcm2835-1.67.tar.gz, not /usr/local/include.
You didn't recompile the library to actually have the added feature in it.
Also, if you're just accessing the GPIO pins and don't need non-root access to /dev/mem then there's no need to do anything more than adding access rights to /dev/gpiomem to your non-root user.
Have you tried version 68 already ?
There where made some changings concerning 'BCM2835_HAVE_LIBCAP'.
Related
I have an out-of-tree Linux kernel module that I need to compile. When I execute "make" in the kernel module directory I am getting:
"fatal error: stdarg.h: No such file or directory"
Before starting the build I installed the header file based on my Linux distribution.
$sudo apt-get install kernel-headers-$(uname -r)
How can I solve this compilation error? (my distribution is Ubuntu 16.04 with linux-headers-4.15.0-42-generic)
I ran a search of stdarg.h with the "locate" command to see if I can sport the file on the system.
I got:
/usr/include/c++/5/tr1/stdarg.h
/usr/lib/gcc/i686-linux-gnu/5/include/cross-stdarg.h
/usr/lib/gcc/i686-linux-gnu/5/include/stdarg.h
...
It tells me there is at least one stdarg.h provided by the compiler.
I tried to include the path "/usr/lib/gcc/i686-linux-gnu/5/include" in the kernel module Makefile so stdarg.h can be picked up. It did not work (while building, another reference to stdarg.h in the official kernel header was not being resolved).
I finally created a symlink directly under:
/usr/src/linux-headers-4.15.0-42-generic/include
$sudo ln -s /usr/lib/gcc/i686-linux-gnu/5/include/stdarg.h stdarg.h
This was just enough to solve the compilation issue.
I am wondering if the kernel headers should come with an implementation of stdarg.h by default (that is the first time I encounter this issue). I have also read that the compiler provide one implementation and most of the time it is better to use the compiler version.
Updated note: if the above solution still does not solve the problem:
Before running make again, do a make clean. Do a ls -la in the folder and look for a ".cache.mk" file. If this is still there, remove it and run "make" again. It should solve the problem.
I had the same issue with CentOS 9, and the other answers didn't work for me. Apparently the problem is that in more recent kernels, it shouldn't be <stdarg.h> but <linux/stdarg.h>. With virtualbox guest additions 6.1.34, it correctly checks for kernel with a version of 5.15.0 or more. But my kernel is the 5.14.xx, meaning the include for stdarg.h is wrong.
Solving the issue
Dependencies
Install all the dependencies for the guest edition
gcc make perl kernel-devel kernel-headers bzip2 dkms
Installation
Run the Guest Addition installation like you would normally. It will fail by saying it is unable to compile the kernel modules. That's expected. It will copy all the file we need to the VM disk.
Editing
We now need to edit the erroneous files.
/opt/VBoxGuestAdditions-6.1.34/src/vboxguest-6.1.34/vboxguest/include/iprt/stdarg.h
/opt/VBoxGuestAdditions-6.1.34/src/vboxguest-6.1.34/vboxsf/include/iprt/stdarg.h
On line 48 (may change for different versions), it check for a version of Linux and select the correct header depending on the version. We need to replace if RTLNX_VER_MIN(5,15,0) with if RTLNX_VER_MIN(5,14,0) in both files.
Compile the kernel modules
We can now compile the kernel modules, and the error should be gone.
sudo rcvboxadd quicksetup all
I personally got an error the first time, but then I recompiled without changing anything and it worked.
Remember that it's just a workaround, it may not work with different versions.
If you using Arch Linux with zen-kernel:
sudo CPATH=/usr/src/linux-zen/include/linux vmware-modconfig --console --install-all
I had the same problem with VirtualBox 6.1.0 running archlinux with kernel 6.1.9.
I downloaded VirtualBoxGuestAdditions_7.2.0.iso file from https://download.virtualbox.org/virtualbox/7.0.2/ link(you may select more appropriate to your VirtualBox version) and assigned as an optical drive to virtualbox machine. After start of the system running blkid command on terminal showed the name of CD rom device which was /dev/sr0. then I created iso folder on
/mnt folder
mkdir /mnt/iso
and mounted cd drive to that folder
mount -o loop /dev/sr0 /mnt/iso
after I cd'ed to /mnt/iso
cd /mnt/iso
and manually run VirtualBoxGuestAdditions.run script
sh ./VirtualBoxGuestAdditions.run
which successfully compiled and istalled required virtualbox guest modules.
Now everytime I update kernel version I redo the same procedure. And it work fine.
It also remove old 6.1.0 guest additons folder.
I have encountered numerous problems in the installation of Wireshark, and the capture of USB traffic, especially due to user permissions.
How to install Wireshark on Linux and capture USB traffic?
Tested on Ubuntu 14.04, but probably works on other distributions since none of the steps are specific to Ubuntu.
The first time you follow the tutorial, do all the steps 1 -> 7.
When you restart your computer, you have to repeat steps 6 and 7 to see the USB interfaces in Wireshark.
Install Wireshark and libpcap:
sudo apt-get install wireshark libpcap0.8
For Debian, Ubuntu and other Debian derivatives, continue to step 3.
For other Linux based systems or other installation methods, see the Wireshark Wiki, then go to step 6.
Reconfigure wireshark to allow non-superusers to track packets:
sudo dpkg-reconfigure wireshark-common
Select <Yes> in the prompt
Add your username to the "wireshark" usergroup:
sudo usermod -a -G wireshark <your_username>
You can verify if it’s done correctly by displaying the groups your username is part of:
groups <your_username>
If not, you can add the group "wireshark" manually:
groupadd wireshark
And then add your username to the group (see above)
Important: Logout of your session, then log back in.
This step depends on the kernel version that is installed on your machine. To know the version of your kernel, type:
uname -r
For versions of the kernel prior to 2.6.21, if debugfs is not already mounted on /sys/kernel/debug, ensure that it is mounted there by issuing the following command:
sudo mount -t debugfs / /sys/kernel/debug
For kernel version 2.6.21 and later, load the loadable module usbmon in the Kernel:
`sudo modprobe usbmon`
See [Wireshark Wiki](https://wiki.wireshark.org/CaptureSetup/USB#Linux) for more information about this differentiation.
If the usbmon interfaces don't appear in Wireshark, look for interfaces using dumpcap (the command-line tool of Wireshark):
sudo dumpcap -D
You should see the usbmon* interfaces. Now display the permissions of the usbmon interfaces:
ls -l /dev/usbmon*
If the usbmon* files have 'crw-------', then it's normal that Wireshark cannot read them because it's not run as root. Do not execute wireshark in root mode, it may damage files. Instead, you can give it regular users privileges :
sudo setfacl -m u:$USER:r /dev/usbmon*
Now the usbmon interfaces should appear in Wireshark.
Sources:
https://wiki.wireshark.org/CaptureSetup/USB#Linux
https://wiki.wireshark.org/CaptureSetup/CapturePrivileges#Most_UNIXes
https://unix.stackexchange.com/questions/55722/wireshark-couldnt-run-usr-sbin-dumpcap-in-child-process
http://anonscm.debian.org/viewvc/collab-maint/ext-maint/wireshark/trunk/debian/README.Debian?view=markup
I've just got my guest box running CentOS working perfectly, except for one problem. I'm trying to mount a shared folder. I've followed the instructions for getting the shared folder "Mountable" by using this code:
VBoxManage sharedfolder add "TEST - 250" --name "github" --hostpath "C:\filepath\github"
Where "TEST - 250" is the name of the VM, "github" is the name of the folder as I'd like to call it in my VM, and "C:\filepath\github" is the directory path on the Windows host where I can find the contents I would like to share.
All seems well, and as instructed by Oracle, I am to use this command in the VM:
sudo mount -t vboxsf shared ~/host
I've made a directory off of the root called "host". The problem here is that I'm getting the following message:
mount: unknown filesystem type 'vobxsf'
Looking at this further, I'm told that in the /sbin/ folder, there should be a file called mount.vboxsf, where there is not.
I then read chapter 4 here: http://www.virtualbox.org/manual/ch04.html ... more specifically section 4.2.2.1.6 for Oracle Linux, Red Hat Enterprise Linux and CentOS. I follow ALL commands they ask for:
yum install dkms
yum update
yum install gcc
yum install kernel-devel
And just in case...
yum install kernel-uek-devel
All seem to work fine. I reboot the system to activate the updates. Once I login to the rebooted system, I type:
ls /sbin/mount*
... and I do NOT see the mount.vboxsf file. What am I doing wrong?
Also, is there a way to just get this file, and place it there? If I had that, I could perform my drive mounting, and be done with what I need to do. Any suggestions?
You need to install guest editions.
"The VirtualBox Guest Additions for all supported guest operating systems are provided as a single CD-ROM image file which is called VBoxGuestAdditions.iso. This image file is located in the installation directory of VirtualBox."
create mount directory
sudo mkdir -p /media/VirtualBoxGuestAdditions
mount guest additions iso
sudo mount -t iso9660 -o loop /installation/directory/of/VirtualBox/VBoxGuestAdditions.iso /media/VirtualBoxGuestAdditions/
Install guest additions
sudo /media/VirtualBoxGuestAdditions/VBoxLinuxAdditions.run
Then mount.vboxsf file should be in sbin and you can mount with
sudo mount -t vboxsf shared ~/host
See https://www.virtualbox.org/manual/ch04.html
After following the steps described by the given answer and experiencing a kernel header issue i came across this link which has a command that does simplify things.
/etc/init.d/vboxadd setup
Hope it helps future explorers on this question. :)
I got the same error.
When I tried to install VBoxGuestAdditions (Devices -> Insert Guest Additions CD Image) on Ubuntu 16.04 x86, it throws error message "Unable to insert the virtual optical disk ..."
SOLUTION:
1. Open a terminal and enter: sudo apt-get install virtualbox-guest-utils
Reboot and enjoy.
sudo ./whateverTheArchitectureTypeYouHaveIs.sh worked for me. By default, VBOXAddition folder is in /media/..
I'm trying to run the time command for a file on a virtual machine running Fedora 19 64-bit and I get the message "/usr/bin/time: No such file or directory". I tried googling, but it appears it's something that I should already have. How do I get this on my computer?
For those on a raspberry pi or similar debian-based distributions, I found that I could install the package time (sudo apt install time) to obtain access to the time command.
Edit: For Fedora-based systems, the package name might be different. Try a dnf search time, followed by a sudo dnf install {package_name}. I don't have a Fedora machine immediately to hand to get the exact package name from.
bash/zsh/modern shells usually implement a basic time command as a builtin. So it won't exist on the filesystem, but time mycommand should work.
If you want the "proper" time command (with more options eg: -l/-v), then you'll need to install it via apt/yum/etc. You'll need to run it as /usr/bin/time mycommand so the shell-builtin doesn't get invoked.
It might be in other locations. I'd start by typing:
which time
This command will give you the path to time, if it's anywhere in your path.
If you need to build it yourself, you can get the source here:
http://directory.fsf.org/wiki/Time
I accidentally deleted the symbol link /lib64/libc.so.6 -> /lib64/libc-2.12.so with
$ sudo rm libc.so.6
Then I can not use anything including ls command. The error appears for any command I type
ls: error while loading shared libraries: libc.so.6: cannot open shared object file: No such file or directory
I've tried
$ export LD_PRELOAD=/lib64/libc-2.12.so
After this I can use ls and ln ..., but still can not use sudo ln ... or sudo -E ln .... I always get this err
sudo: error while loading shared libraries: libc.so.6: cannot open shared object file: No such file or directory
It's a remote server so I can not use a live CD. I now have a ssh bash session alive but can not establish new ones. I have sudo privilege, but don't have root password.
So currently my problem is I need to run sudo sln -s libc-2.12.so libc.so.6 to re-create the symlink libc.so.6, but I can not run sudo without libc.so.6.
How can I fix it? Thanks~
I resolved the issue by using a statically linked version of "ln" that was already in the server's /sbin.
E.g., this restored it for my configuration:
/sbin/sln /lib64/libc-2.5.so /lib64/libc.so.6
A bit embarrassing :) but it happened to me as well on Ubuntu 12.04.3 (which is not CentOS 6.4 but I thought this could still help maybe).
Because my Ubuntu wouldn't start I used a liveUSB to boot up and then mounted my hard drive and created the symlink (I did have the file itself libc-2.15.so) and that did it.
Just a few specific details:
I asked a good friend to use his computer for half an hour
I Downloaded my exact Ubuntu iso (12.04.3, if you're on;y missing the symlink, it could be any version so much that it can mount drives) from here: link
I made sure his Ubuntu has usb-creator-gtk ($ sudo apt-get install usb-gtk-creator, I'm sure Windows has an equivalent usb boot creator)
Created the liveUSB using usb-creator-gtk
Booted my computer with it (you'll probably need to change your BIOS settings to allow external USB to be booted first)
Once I booted from the live USB I figured where my hard drive partition by running the Ubuntu partition tool (the live USB has one) - mine was of type ext4 and in /dev/sdb1
I mounted it by doing $ mkdir /home/ubuntu/mnt and then $ sudo mount-t ext4 /dev/sdb1 /home/ubuntu/mnt
I then proceeded to that folder $ cd /home/ubuntu/mnt
From that location I then created the symlink by $ sudo ln -s lib/x86_64-linux-gnu/libc-2.15.so lib/x86_64-linux-gnu/libc.so.6
After a reboot I was good.
Hope it helps you (or someone..)
I would add some thing more to #wilfo answer as same also happened with me [accidentally deleting lib.so.6 and was getting /sbin/init missing libc.so.6 on boot up] .
After creating liveUSB in windows (using UNetbootin etc [http://unetbootin.sourceforge.net/]) or in ubuntu as #wilfo suggested.
Booting from liveUSB, I selected "experience ubuntu without installing it" and was happy applying wilfo's method until step 6 and then i couldn't find my hard drive partition of type ext3/4. All were nftf/fat/extended stuff.
So i recovered previous ubuntu (the one with missing libc.so...) by following this link
https://help.ubuntu.com/community/Boot-Repair
make sure to follow all necessary steps and take a backup of your ubuntu partition.
you can see your previous ubuntu files inside /mnt/boot-sav/wubi1/home
take a backup from here to your windows partations /mnt/boot-sav/sda...
and follow remaining procedure here https://help.ubuntu.com/community/Boot-Repair