i'm running raspbian (2015-05-05-raspbian-wheezy.img) in qemu using compiled kernel (https://github.com/dhruvvyas90/qemu-rpi-kernel) on ubuntu 14.04. my final goal is to launch my python script within the emulation.
i'm following manual from http://www.unixmen.com/emulating-raspbian-using-qemu/, though many others suggest very similar sequence of actions.
things i'm trying and issues i'm experiencing:
first boot is more or less ok. i comment the line in /etc/ld.so.preload as suggested and reboot.
on second boot (after i remove init=/bin/bash) and all subsequent boots i get
ERROR ../libkmod/libkmod.c:554 kmod_search_moddep: could not open moddep file '/lib/modules/3.10.25/modules.dep.bin'
some googling suggested to run "sudo rpi-update". it didn't help, same message during boot.
on second boot (after i remove init=/bin/bash) and all subsequent boots i get
fsck died with exit status 6
looking into "/var/log/fsck/checkfs" as suggested tells that some location is not there, but it doesn't say which one
running "startx" produces error message from 1. it loads the UI eventually, but desktop only has "wastebasket" icon. there is also a thick white stripe on top of the screen blinking, like it keeps trying to load a tab but fails everytime. qemu window stops to respond to further interaction after this.
running "sudo apt-get upgrade" installs some packages, but after reboot i can't even get to UI - just blank screen with mouse cursor.
i'm not very experienced with how linux is configured at low level. i understand that i might be doing something completely stoopid.
so, my questions are:
how do i debug? i couldn't figure out the settings for qemu to write logs. i really don't want to fallback to gdb, as i'm not debugging qemu itself, just want to get notification on it's events.
ctrl key doesn't seem to work inside qemu window.
no copy-paste available. or i can't see how to turn it on.
am i missing something? from all the manuals i have seen it seems like this should go much much smoother. like it should "just work".
Since your post many things changed. The most important things is that now using Andrew Baumann GitHub repo you can build QEMU that boots recent Raspbian. I described my experience woth this code here. Instructions are straight forward. Implementation needs polishing but it best compilation of work so far.
To answer your questions:
QEMU have -s and -S options for GDB. First option setup gdb server hook and second freez CPU, so you can connect debugger. This is not for QEMU debugging this for guest system debugging. Default QEMU logging is to stderr, so if something valuable happen you will see it in terminal. You can raise QEMU verbosity by uncommenting various *DEBUG_ statements in source code. Also check help for -d and -D command line flags of QEMU.
Not sure I can help with this. Only thing that I can say is that my QEMU version 2.5.50 reacts to Ctrl+Alt which exits from GUI after capturing cursor, so it looks like QEMU understand Ctrl key. I assume that QEMU do not capture your special keys combination because your window manager do it before passing to QEMU.
This also not work for me, but I see some work was done in this area. Not sure how to enable and use that feature.
Emulating any hardware is very complex and requires a lot of work. All emulated targets are limited to some most important features. BCM2835/BCM2836 (Raspberry Pi/Raspberry Pi 2) SoC are still not accepted by mainline QEMU, so just work will not apply to those platforms.
Related
I am using Windows 10.
I downloaded setup-x86_64.exe from https://cygwin.com/install.html and am selecting the defaults (Install from Internet/Direct Connection/default locations).
I have tried several mirrors including cygwin.mirror.constant.com
I am accepting all the default packages plus some basic developer stuff (gdb, make) and check "Select required packages (RECOMMENDED)".
I get quite a way through the Cygwin Setup and then get the first of many pop-up messages "IO Error Opening file....._autorebase/binutils/cygwin/grep/mintty etc. Do you want to skip this package?"
If I skip the packages, I get a non-working Cygwin install (it can't find mintty). If I don't skip the packages, it hangs when the Cygwin installer hangs when it gets to the first of the problem packages.
Thanks in advance about what part of the setup process I am missing.
A bit late, but anyway: I have stumbled across the same problems yesterday when I tried to install Cygwin on Windows 10 the first time.
I have followed all advice given at various sites (including this one): Disabled antivirus software, followed the Cygwin FAQ, and so on, but to no avail.
Then I studied the setup log and found a line which told something about an address mismatch (sorry that I don't have the exact wording - I surely won't repeat the experiment ...). That lead me to the idea that it might something have to do with ASLR (a technique for hardening the system against malware).
The next step was to turn off ASLR via the UI of Windows Defender. After I had done that, I could install Cygwin without any problems. I have not yet tested if I actually could use Cygwin when I turn on ASLR again; I don't feel very comfortable when having turned it off completely.
The alternative would be to turn off ASLR per executable. This is also possible in Windows Defender's UI. But it could mean adding dozens of exceptions, depending on how many Cygwin packages you have installed.
The technical reason for the problem is how POSIX's fork() works. Basically, it clones the parent process's image, using the same offset addresses. But when ASLR is active, those offsets will change when cloning the process, which will make fork() fail. Since fork() is extensively used by Cygwin, it can't operate as intended when ASLR is active.
Im looking for a way how to get rid of (kernel?) messages that appear in my ncurses app. I wrote the app myself, so i would prefer a API that redirects these messages to /dev/null. I mean messages like, a USB stick that is inserted.
I tried to add this, but unfortunately it doesn't work
freopen("/dev/null", "w", stderr);
I'm not running X, just ncurses direct from the console.
I mean messages like, a USB stick that is inserted.
Thanks!
UPDATE 1:
Someone votes to close this question because it would not be related to programming. But it is, i wrote the ncurses app myself, i'm looking for a way how to disable the kernel message. I updated the question.
UPDATE 2:
Let me explain what i'm doing, and whats the problem in more detail:
I'm using Tiny Core linux, thats after boots starts (self written) ncurses program. Now when you for example connect a USB drive, a message (i suspect kernel) is shown over my program. I guess the message is written straight into the framebuffer. Im using TC 5.x since i need 32 bit, im running as root and have full access to the os.
You should be able to use openvt to have your program run on a new Virtual Terminal.
I'll also note that it should be possible to embed control for the VTs yourself if you prefer to break the external dependency, but note that structures used may not be stable between kernel versions, and may require recompilation.
See the KBD project's sources, specifically openvt.c to see how it works.
Try configuring the kernel through boot parameters with the option:
loglevel=3 (or a lower value)
0 (KERN_EMERG) system is unusable
1 (KERN_ALERT) action must be taken immediately
2 (KERN_CRIT) critical conditions
3 (KERN_ERR) error conditions
4 (KERN_WARNING) warning conditions
5 (KERN_NOTICE) normal but significant condition
6 (KERN_INFO) informational
7 (KERN_DEBUG) debug-level messages
source: https://www.kernel.org/doc/Documentation/kernel-parameters.txt
See also: Change default console loglevel during boot up
It might be impossible to block some other process with sufficient access from writing to /dev/console but you may be able to redefine console as some other device, at boot time by setting console=ttyS0 (first serial port), see:
https://unix.stackexchange.com/questions/60641/linux-difference-between-dev-console-dev-tty-and-dev-tty0
Also if we know exactly which software is sending the message it may be possible to reconfigure it (possibly dynamically) but it would help to know the version and edition of Tiny Core Linux you are using?
E.g. this website has a "Core", "TinyCore" and "CorePlus" versions 1.x up to 7
http://tinycorelinux.net/downloads.html
This would help reproducing the exact same behavior and testing potential solutions.
I want to run a program when my embedded Linux's desktop has started up, in the same way as Windows runs programs in the "Startup" folder. How can I do this?
Specifically, my target hardware is Beaglebone Black, the Debian variant (rev C board). The Window Manager is the default one.
In Linux these are called init scripts and usually sit in /etc/init.d. How they should be defined varies between different distros but today many use the Linux Standard Base (LSB) Init Script format.
Good readings on this:
https://wiki.debian.org/LSBInitScripts
https://www.debian-administration.org/article/28/Making_scripts_run_at_boot_time_with_Debian
There are multiple ways to start a program, it turns out. LXDE - the window manager - supports auto-start of .desktop files places in either ~/.config/autostart or /etc/xdg/autostart - hooray!
http://wiki.lxde.org/en/Autostart
Except... though I can run a simple program as proof-of-concept in this way, when I try to run mine, it fails. I can't figure out why. The file
.xsession-errors.old
contains X server errors ("resource temporarily unavailable").
I am now using another mechanism - running the code from a shell script (this is necessary because I need to specify a working directory for the program). This uses the "autostart" file in /etc/xdg/lxsession/, and at least it works. Well kind of. I either have to "sleep 5" before running, or prefixing the run with an # symbol which forces a retry if it fails. It looks a little like something my code is dependent on is not in place at the precise time the autostart mechanism finds it. I can find no way of ensuring startup order. This is plainly a crock of stinky stuff.
First off, sorry for my english, it is not very good.
I have a Toshiba satellite c885d running windows 8.1. I have a lexar 4 gigabyte usb flashdrive. It says on the back: LJDS50-4GB. I used Linuxlive usb creator and backtrack 5 r3 gnome 32 bit. I downloaded the ISO from backtrack-linux.org.
When I put my usb into my computer, hold f12, and power it on, it takes me to the boot menu, where it gives me 4 options to boot from. after each one, there is a little bit of text. except after "usb" is blank. and then at the bottom is two more options, one taking you to the menu that you can also access by pressing f2 durring startup.
If I hit enter when usb is selected, it takes me to a black screen that says two words (something like checking usb, but I forgot. I will put in an edit that will contain a picture and the exact text.) then after 2 seconds, it says failed, and then launches windows. PLEASE PLEASE PLEASE help me out. I tried researching a solution to the problem, none of which worked. I have successfully run backtrack from the VM thingy that linuxlive has with all of the usb stuff, and It works fine, but it is really slow, as I have too many windows processes running at the same time. If anyone can diagnose me with a problem, awesome. If you can give me a solution, stupendous.
edit: it says "checking media" and then "failed"
images:
Ok, after some discussion in question comments I suspect that the problem is in your install image. If you can't see GRUB menu then you are unable to enter bootloader on your USB drive. It might be several things causing your problem with common denominator - UEFI:
You have written your install image incorrectly and UEFI is not recognizing it.
You have written your install image correctly, but that image is not capable to run on UEFI - see discussion here.
Anyway 100% way to make Backtrack like most of current Linux distros to work on UEFI is to turn UEFI to legacy mode (BIOS), though you have to unninstall Windows 8 ;-)
I would not give lot of hopes to that because Backtrack 5 is based on Ubuntu 10.04 which is way too old - earliest Ubuntu supporting UEFI is 12.04.
I can recommend a few things that might help:
Erase your usb flash drive and write Backtrack image to it again, but with UnetBootIn. There is an official tutorial for that.
Do not try to install Backtrack 5 if don't know what GRUB is. You can install latest Ubuntu that can run on UEFI with SecureBoot (not sure it's easy) and enjoy all of the tools from Backtrack repositories.
Good Luck and have a lot of fun!
I figured it out, just had to follow the tutorial from this page: https://askubuntu.com/questions/221835/installing-ubuntu-on-a-pre-installed-windows-8-64-bit-system-uefi-supported
I am booting up a linux kernel using a full system simulator, and I'd like to run my benchmark on the booted system. However, when it boots up, it shows me this message: "clocksource tsc unstable" and occasionally it hangs in the beggining. However, sometimes it lets me run my benchmark and then probably it hangs in the middle since the application never finishes and seems it's stuck there. Any idea how to fix this issue?
Thanks.
It suggests that, kernel didn't manage to calculate tsc (Time Stamp Counter) value properly i.e value is stale. This usually happens with VM. The way to avoid this is to - use predefined lpj (loops per jiffy) as kernel parameter (lpj=). Try it, hope issue will be fixed!