A maybe stupid question: For an embedded project I want to switch the single processes (currently running as root) to capabilities. Since the project also includes several shared libraries, my approach is to switch parts in the libraries to use capabilities.
But a first test with 'seteuid()' and a system() call did not run successfully. Only when I replaced 'seteuid()' with 'setuid()' I had success.
For your information: The 'system()' call should delete a file in /sbin (rm /sbin/xyz).
When I started the project, I found a page on the internet about caps and shared libs. Unfortunately I can't find it anymore.
Can someone please give me info, or a link, on the topic of caps and shared libs?
Thanks
Related
I am building a kiosk application using webkitgtk on the raspberry pi 4.
This application will not be connected to the internet and all the html,css, javascript for the UI are all located on the local filesystem.
I am using buildroot to setup the Linux system, starting with the pi 4 defconfig provided in buildroot.
I have enabled all the packages needed to get webkitgtk running.
Also, the kiosk application has been tested on my desktop, using the same software stack and it works
However, when i try to launch the application on the raspberry pi, a blank page pops up. I have played around with the WebKitWebSettings object associated with my WebKitWebView by enabling local file access. It still shows up a blank screen.
Also included in my pi4 application bundle is a simple gtk3+ application. This launches successfully!
I will really appreciate some pointers as to why this is happening as i have sort of reached a dead end
UPDATE
I enabled the MiniBrowser app that comes with the Webkitgtk package.
Entering the local url, The page does not load. It only gives me a message at the top saying "Successfully downloaded".
It seems to be treating my input as a download
UPDATE 2
After some more experimenting, i was finally able to get webkitgtk working on the pi 4.
The problem seems to originate from using the webkit_web_view_load_uri() api.
It does not seem to recognize my html document as a web page.
I got around it using the webkit_web_view_load_html() call. This included some hacks by first reading in the contents of the html doc into a character buffer, and passing it to webkit_web_view_load_html().
You also have to provide a base path to this function call to be able to resolve all the urls (scripts, css, images etc) in your html document.
Another problem i haven't been able to work around is, SVG images are not loading in webkitgtk. I have used jpg formats and they work. I suspect this my be due to a configuration switch in building webkigtk
It's hard for me to figure out what might be happening without having access to your environment and settings. My gut feeling is that pages are showing blank because perhaps some shared libraries are missing. You can check that with:
$ ldd WebKitBuild/GTK/Release/bin/MiniBrowser
I am using buildroot to setup the Linux system, starting with the pi 4 defconfig provided in buildroot.
There's a buildroot repository for building WPE for RPi. WPE (WebPlatform for Embeded) is like WebKitGTK but doesn't depend on GTK toolkit. Another important difference is that WPE runs natively on Wayland.
If you're interested in having a webapp embedded in a browser running in a device with limited capabilities, WPE is a better choice than WebKitGTK. The buildroot repo for building WPE for RPi is here:
https://github.com/WebPlatformForEmbedded/buildroot
There's is also this very interesting step-by-step guide on how to build WPE for RPi3:
https://samdecrock.medium.com/building-wpe-webkit-for-raspberry-pi-3-cdbd7b5cb362
I'm not sure whether the buildroot recipe would work for RPi4. It seems to work for all previous versions, so you might be stepping in new land if you try to build WPE on RPi4.
If you have an RPi3 available I'd try to build WPE for RPi3 first, and make sure that works. Then try for RPi4.
I'm using PreEmptive Protection Dotfuscator for winform executable .exe file.
Do I have to add Map.Xml and Dotfuscator1.Xml to Setup Project with other Dependencies to locate it in Program Files/MyApp directory, or it is no needed?
(Disclaimer: I am a developer on Dotfuscator and am answering this as part of my job.)
No, after Dotfuscator has run and created a protected/obfuscated .exe file, you typically do not need to involve the Map.xml or Dotfuscator1.xml files in any later step of your build process. Your protected .exe file will be able to run without them, and they are not needed when building your setup executable.
In fact, these files contain sensitive information that could be used to undo parts of the obfuscation. Do not add these files to an installer project, packaging project, or anything that could potentially leave your organization. For details, including how to handle these files as part of your development process, see my answer here.
I have to create one-file (.exe) program.
In this program user can choose directory from his computer.
I create program in order of http://www.tarnyko.net/en/?q=node/31 and it run well.
But when I invoke FileChoser (click on button) I got this error
GLib-GIO-ERROR No GSettings schemas are installed on the system
Response of Tarnyko to this issue is in coment on webpage - this is known "bug" with static compiling.
How can I work around this?
On the one hand I have to have one-file.exe.
On the other hand I realy do not want create "sophisticated" FileChooser on my own... is there any option to deal with this?
My ideas:
1 - Call native File chooser of OS (windows)
2 - Create file chooser on my own - if it is not "much hard" in gtk
I do not know how to do either of this.
Sorry for duplicating - probably succes solution is in answer form "ebassi" here GLib-GIO-ERROR**: No GSettings schemas are installed on the system (not tested yet)
Settings schemas (which are used in GTK in more places than just the file selector widget) cannot be statically linked into a binary: they have to be installed in a well known location (controllable via the $XDG_DATA_DIRS environment variable) and they have to be compiled into a cache.
GTK's dependencies like Pango and GDK-Pixbuf also use ancillary files and loadable modules that are not strictly compatible (unless you're willing to spend time on it) with static linking.
The usual recommendation for only providing a single executable for your application is to have a self-extracting installer that contains all the installed files necessary to running a GTK application, and avoid static linking.
I don't think it's possible to create just one .exe file (without any other files) with GTK+. Maybe only when you recode the GTK and it's dependencies - which is not an easy task to do.
The best solution I found is to put all schemas (and also icons for your GTK+ app) in the same location where your .exe file is placed:
EXE_LOCATION\program.exe
// For icons:
EXE_LOCATION\share\icons\hicolor...
// For schemas
EXE_LOCATION\share\glib-2.0\schemas
Then you deliver these files together with your .exe file and with all needed .dll files.
About the native file chooser in GTK+: It also needs the schemas - at least on Windows OS.
I make a fair amount portable Apps for personal use and they work perfectly for the most part. I do, however, find it quite frustrating that if I run them on another computer none of my preferences are retained, as a program always looks in appData for the configuration files (which obviously don't exist on another system), so I'm wondering whether there is some kind of command line to launch an .exe with a custom .ini location.
I'm asking this firstly because Google has proved fruitless (once again) and secondly because I know it's possible - I've actually done this before, but with only one of my Apps. I accomplished this by launching the App via the command programFile.exe -f configFile.ini /s (I have also seen programFile.exe -d -f configFile.ini /s elsewhere). Naturally, I thought I would try to apply this to some other Apps but it seems it only works for that particular App.
So, is there a command/switch that I am unaware of that will do this for an .exe file?
Thanks
It really depends on each executable file you are using. Some have support for what you are looking for, and some don't. Some programs don't even use .ini files. What you should look for is if each and every program you use have support for user data custom location.
Edit
The only case where generic arguments would be avaialble for a group of EXE files is if they are generated with the same tool, which automatically provides these arguments for you. InstallShield and MSI install programs have that kind of feature (with the silent install and automated installation for instance).
I suggest you look into the tool you are using to generate your portable Apps, and see if it does provide those generic arguments for you, and how they work. If it does not have that feature, then look into the Apps you were able to specify a custom location for your INI file. Somewhere into the code, there must be a piece of code that handles the arguments you specify to the EXE file and handles them. You should share that piece of code with your other Apps, to make sure they provide the same arguments list.
I'm doing some Linux kernel development, and I'm trying to use Netbeans. Despite declared support for Make-based C projects, I cannot create a fully functional Netbeans project. This is despite compiling having Netbeans analyze a kernel binary that was compiled with full debugging information. Problems include:
files are wrongly excluded: Some files are incorrectly greyed out in the project, which means Netbeans does not believe they should be included in the project, when in fact they are compiled into the kernel. The main problem is that Netbeans will miss any definitions that exist in these files, such as data structures and functions, but also miss macro definitions.
cannot find definitions: Pretty self-explanatory - often times, Netbeans cannot find the definition of something. This is partly a result of the above problem.
can't find header files: self-explanatory
I'm wondering if anyone has had success with setting up Netbeans for Linux kernel development, and if so, what settings they used. Ultimately, I'm looking for Netbeans to be able to either parse the Makefile (preferred) or extract the debug information from the binary (less desirable, since this can significantly slow down compilation), and automatically determine which files are actually compiled and which macros are actually defined. Then, based on this, I would like to be able to find the definitions of any data structure, variable, function, etc. and have complete auto-completion.
Let me preface this question with some points:
I'm not interested in solutions involving Vim/Emacs. I know some people like them, but I'm not one of them.
As the title suggest, I would be also happy to know how to set-up Eclipse to do what I need
While I would prefer perfect coverage, something that only misses one in a million definitions is obviously fine
SO's useful "Related Questions" feature has informed me that the following question is related: https://stackoverflow.com/questions/149321/what-ide-would-be-good-for-linux-kernel-driver-development. Upon reading it, the question is more of a comparison between IDE's, whereas I'm looking for how to set-up a particular IDE. Even so, the user Wade Mealing seems to have some expertise in working with Eclipse on this kind of development, so I would certainly appreciate his (and of course all of your) answers.
Cheers
Eclipse seems to be pretty popular for Linux kernel development:
http://cdtdoug.blogspot.com/2008/12/linux-kernel-debugging-with-cdt.html
http://jakob.engbloms.se/archives/338
http://revver.com/video/606464/debugging-the-linux-kernel-using-eclipsecdt-and-qemu/
I previously wrote up an answer. Now I come up with all the details of the solution and would like to share it. Unfortunately stackoverflow does not allow me to edit the previous answer. So I write it up in this new answer.
It involves a few steps.
[1] The first step is to modify linux scripts to leave dep files in. By default after using them in the build, those dep files are removed. Those dep files contains exact dependency information about which other files a C file depends. We need them to create a list of all the files involved in a build. Thus, modify files under linux-x.y.z/scripts to make them not to remove the dep files like this:
linux-3.1.2/scripts
Kbuild.include: echo do_not_rm1 rm -f $(depfile);
Makefile.build: echo do_not_rm2 rm -f $(depfile);
The other steps are detailed in my github code project file https://github.com/minghuascode/Nbk/blob/master/note-nbkparse. Roughly you do:
[2] Configure with your method of configuration, but be sure use "O=" option to build the obj files into a separate directory.
[3] Then use the same "O=" option and "V=1" option to build linux, and save make output into a file.
[4] Run my nbkparse script from the above github project. It does:
[4.1] Read in the make log file, and the dep files. Generate a mirroring command.
[4.2] Run the mirroring command to hard-link the relevant source files into a separate tree, and generate a make-log file for NetBeans to use.
Now create a NetBeans C project using the mirrored source tree and the generated log file. NetBeans should be able to resolve all the kernel symbols. And you will only see the files involved in the build.
The Eclipse wiki has a page about this: HowTo use the CDT to navigate Linux kernel source
I have been doing some embedded linux development. Including kernel module development and have imported the entire linux kernel source code into Eclipse, as a separate project. I have been building the kernel itself outside of Eclipse(so far), but I don't any reason why I shouldn't be able to set up the build environment within Eclipse to build the kernel. For my projects, as long as I setup the PATH properties to point to the appropriate linux source include directories, it seems to be pretty good about name completion for struct fields, etc.
I can't really comment, on if it is picking up the correct defines and not greying out the correspond sections, as I haven't really paid to much attention to the files within the kernel itself.(so far)
I was also wondering about using Netbeans as a linux 'C' IDE, as I do prefer Netbean's for Java GUI development.
I think this would work (done each step for various projects):
[1] Modify kernel build scripts to leave .d files. By default they are removed.
[2] Log the build process to a file.
[3] Write a script to parse the build log.
[3.1] From the build log, you know every .c files.
[3.2] From the .c file, you know which is the corresponding .d file.
[3.3] Look into .d files to find out all the included .h files.
[3.4] Form a complete .c and .h file list.
[4] Now create a new dir, and use "ln -s" or "ln" to pick files of interest.
Now, create a Netbeans project for existing source code in the [4].
Configure code assistance to use make-log file. You should see
exactly the effective source code as when you build it at [2].
Some explanations to the above steps:
At [2], do a real build so the log file contains the exact files and flags of interest.
Later netbeans will be able to use the exact flags to parse.
At [4], pick only the files you want to see. Incorporating the whole kernel tree into netbeans will be unpractical.
There is a trick to parsing .d files: Many of the depended items are not real paths to a .h file, they are a modified entry for part of the linux config sections in the auto config file. You may need to reverse the modification to figure out which is the real header file.
Actually there is a topic on netbeans site. This is the discussion url: http://forums.netbeans.org/ntopic3075.html . And there is a wiki page linked from the discussion: wiki.netbeans.org/CNDLinuxKernel . Basically it asks you to prefix make with CFLAGS="-g3 -gdwarf-2" .
I found this link very helpful in setting up proper indexing in Eclipse. It requires running a script to alter Eclipse environment to match your kernel options, in my case
$ autoconf-to-eclipse.py ./include/generated/autoconf.h .
An illustrated guide to indexing the linux kernel in eclipse