Control gdb running on remote target - c++

I have ability to run gdb on remote target and if I debug directly on this remote, everything is good. But the problem that I don't want to use pure command line gdb.
I want:
Integrate remote gdb with host QT Creator
Highlight source code when debugging remote
Also I want try to avoid using remote debugging by gdbserver, because it's too difficult and I've encountered multiple problems.
These problems:
On host machine I have to have copy of application
All multiple shared libraries should be resolved (with the same version)
Leads to have copy of remote root filesystem or to mount this one by sshfs.
...
If it is possible I'll just write plugin for QT Creator.
Can't I control remote gdb and send them commands like "break", "run", "print"?

Related

How do breakpoints work when using a remote build host in NetBeans?

I have been tasked with setting up a development environment for an embedded platform. So far, I have set up a remote build host in NetBeans, which copies all of the source files to the target device, compiles them natively with the GNU toolchain on the device (g++, ld, etc.), and then runs the compiled binary and forwards stdout to the development machine that NetBeans is running on.
What I don't understand is: How does the binary on the build machine know where and when to start/stop if the breakpoints exist only in NetBeans? The build host only required ssh access and a compiling/linking toolchain, but somehow seems to communicate with NetBeans for debugging. A colleague of mine suggested it uses gdbserver, but I have not found any documentation on the NetBeans website about this package, and it is not installed on the build host (at least not from apt). How is NetBeans doing this?
GUI IDE's which use (or can be configured to use) a distinct command-line toolchain for compilation and debug typically do this by running each required toolchain program as a subprocess and interacting with it through standard streams. Essentially, the IDE would use gcc or gdb with the same textual interface used when running it in a terminal window. The IDE uses its knowledge of lines in the source file to configure breakpoints in gdb much as you would while running it by hand.
In your case, the IDE is configured to use a "remote host" for all of this, so instead of being invoked locally, the toolchain is controlled through as ssh session to the remote machine where both building and running occur.
Because the gdb debugger and the target program are running on the same computer, no gdbserver is required.
In the cases where gdb is too large for the target system, gdbserver is a small program which often gets cross-compiled for the target and loaded onto it. This serves as a compact little delegate which talks to the main gdb program running on a build machine via a serial or network connection and performs the raw interaction with processor, memory, and running program on behalf of gdb.
Another possibility is that the gdbserver role is held by a helper program running on the same machine as gdb which instead commands something like a JTAG debug adapter to interact with the target hardware at a lower level. In this case however, the helper program implementing the gdbserver protocol is not usually called "gdbserver" but instead has an implementation specific name, for example openocd.
gdb runs on the target machine. Only communication with gdb (commands etc) goes via net to your local machine. Read gdb documentation if need to know more/
You can do exactly the same - just open the remote terminal , run gdbserver, start gdb and you are done :)

Eclipse Remote Debugging CDT tutorial

TL;DR: is there a step by step tutorial to do remote code debugging using Eclipse Neon?
I have the source code in a Linux machine with a GCC dev environment. Normally, I ssh to the box, edit the file, and compile/debug using gdb, and it works, but it is a bit clunky for me.
I am now trying to debug the code from my Windows machine using the latest Eclipse version (Neon as of this writing).
I've tried following the instructions online (like this one), but they all seem to point towards (cross-)compiling the code locally, deploying it remotely and debugging there. This is not what I'm after. I essentially want to use Eclipse as a remote text editor+gdb interface, with the building and compiling being done in the remote system.
I've installed CDT, plus pretty much any plugin remotely related to remote development
Remote System Explorer
Remote Launch
GCC Cross compiler support
Remote (over TCF/TE) Run/Debug Launcher
Direct Remote C++ Debugging
TCF C/C++ Debugger
TM Terminal
So far, I can connect to the remote system, create a Remote Project and edit the source code.
I don't need Eclipse to compile the code (I can do that separately) but I'm unable to debug the code.
Using C/C++ Remote Application fails in many creative ways when trying to find gdb in the remote system.
Using GDB (DSF) Automatic Remote Debugging Launcher ends in a java.lang.NullPointerException, which also invalidates the configuration
Using Direct Remote Debugging Launcher asks about a remote workspace, then complains with "Error with command: gdb --version Cannot run program "gdb": Launching failed"
Remote Application complains about the Process/Image field. Setting it to the binary output doesn't enable the Debug button, so no dice.
TCF is dead in the water. It doesn't recognize the SSH connections I set up on RSE, it asks for the username password (I use public keys) and root password (?!) Even when entering that info, it fails to continue.
On a whim, I tried NetBeans, and followed the instructions here, and got it working in five minutes. The mode I'm following is the "Full Remote Development" according to NetBeans. The reason I'll still need to stick to Eclipse is that it is the dev environment that we use in the company, and it makes little sense to me to add another IDE to do something that Eclipse by all rights should do no problem.
What I find is that the walkthroughs for Eclipse I've found are either
Using plugins that are now either deprecated, not supported or have been completely reworked. Eclipse crashes and burns on these.
Trying to compile locally and deploy remotely, doing things like embedded even, but that's not what I'm looking for.
Using the Eclipse DStore client-server combo, which is essentially an alternative to SSH, but not what I'm looking for either.
I'm then hoping someone has written/found a tutorial that is relatively simple to follow (it is, after all, a relatively simple thing to do, as NetBeans has proven), and that works on any version of Eclipse.
I'll consider using an older version of Eclipse, but if so, please be specific in which version I should use, and which plugins I should install.

How to debug a linux C++ program from Windows with Eclipse?

I use a headless (i.e. no screen) remote ubuntu server x64 for developping a C++ application (with no UI either).
I want to conveniently (IDE like, not command line) debug this program from windows (7/64), with Eclipse if possible. I have a windows share between the two and full root access on both machines.
So far I have heard of two solutions :
Remote gdb
Remote X server
I have worked on solution 1 : built a cross gdb, copied my program and libs on windows. I'm able to remote-gdb from cygwin command line, but not from eclipse (stuck at "launching... 85%" with no error message nor log)
I have also worked on solution 2 : installed xauth, set X forwarding, installed xming on my windows, set DISPLAY on the linux box. But no effect "can't open DISPLAY xxx" with no easy troubleshoot.
When googling for those problems, I only find outdated pages or different problems.
Did anyone do it ? Can you share advices or fresh pointers on how to remote debug a C++ linux app from Windows ?
I suggest to install an X11 server on your Windows machine (e.g. Xming perhaps?) and to do ssh -X with some X11 client applications (like emacs, ddd if needed, xterm) on your Linux server. Don't use a complex thing like Eclipse. You could just use emacs (remotely on the Linux server, displaying on the Windows desktop X11 server)...
Once emacs works well (running on the remote Linux server, displaying on the Windows desktop X11 server), you can run gdb inside it.
To get ssh -X working, you need to configure it appropriately. Maybe you forgot that step. To test it, just use ssh -X yourlinuxhost xterm, and work on configuration till that step works.
Of course you could also install Linux on your laptop or desktop, perhaps inside a virtual machine above your Windows.
NB. I never used Windows, but I do know that some X11 servers exist for it.
There is a eclipse plugin RSE (Remote System Explorer), it can pretty much do what you are expecting. The code base can be in linux server, eclipses uses telnet / ssh to login. Execution again can happen on a server, native gdb is used to debug.
You can use the following simple plugin for Eclipse.
http://marketplace.eclipse.org/content/direct-remote-c-debugging
It needs just ssh connection to the server and it cares about anything else

How to run and debug C++ application in Eclipse that's started with a script?

I'm trying to use Eclipse CDT on Ubuntu for C++ development. I'm working on a large C++ project that leverages Tcl as a scripting language to kick off and control the application.
How can I configure Eclipse to launch the application using shell scripts rather than using a C++ "main" application? The shell scripts launch a Tcl application that in turn calls into the C++ application.
Also, is it possible to debug a C++ application using Eclipse and gdb that's started via a script? If so, how does one go about doing it?
Interesting question. Without being able to provide you a straight solution, but Eclipse (gdb) can be attached to a running program - that may not help in your case.
What about trying to employ some kind of remote debugging? I.e. you start your program with gdb and configure gdb to wait for a remote debugger to attach? The 'remote' debugger will be on your local system, of course.
EDIT:
Start your program via
gdbserver localhost:1234 <executable>
Configure your debug session in Eclipse:
- GDB Hardware Debugging
- I had to select the "Standard GDB Hardware debugging launcher" (Debugger tab at the bottom for Helios)
- Check use remote target: Generic TCP/IP: localhost, port 1234
I didn't manage to resolve symbols yet, that might be a path issue.

Remote GDB debugging

I've just spent a whole day trying to find a way to enable GDB debugging from Qt Creator or Eclipse. I learned that there are basically two approaches to launch the target application:
Using ssh (ssh host gdb)
Using gdbserver
I was able to use both approaches to launch gdb remotely and start the application. However, GDB never responds to any breakpoints set in the IDE. Also I can't pause the application to inspect the program state. In Qt Creator I just get an obscure stack trace (I might have been looking at the traces of ssh or gdb actually...).
Can anyone help me to get started?
Progress!
I found that with Qt Creator 2.0 there is an feature called "Attach and debug remote application." It's based on gdbserver. The good thing is that it stops on the IDE's breakpoints. However, there are two issues:
When it hits a breakpoint it only shows assembly code, not the source code.
GDB often quits because of 'signal received'
I should probably mention that the remote executable is compiled with an older version of GCC than the one installed on my local PC. Perhaps some of the problems are related to this.
Update
I should mention that I switched to running cgdb on the remote machine via SSH.
The remote Qt Creator-based solution wasn't stable. GDB tends to quit because of mysterious 'signal received' messages.
So that GDB on your host (the machine you develop and compile on, so where you have Qt Creator) you have to give it access to the "symbol file".
I usually don't use Qt Creator, but GDB and gdbserver directly for cross-compiled programs remote-debugging. You could maybe give this a try to be sure that this works for you and maybe then find the missing option in Qt Creator (or maybe this will help you find what is missing).
On the target machine run:
gdbserver :5000 yourprogram
On the host machine, run gdb and then load the symbol file:
(gdb) symbol-file yourprogram
On GDB on the host machine, you then have to connect to connect GDB to the remote gdbserver:
(gdb) target remote target_ip_address:5000
From then you can use GDB on the host controlling the program on the target.
I hope this helps!
Due to peculiarities in our makefile build system the file references contained in the debugging symbols look like this:
../src/main.cpp
../../src/utils/logger.cpp
This is no problem for GDB, but Qt Creator was unable to map these paths to the actual files. I was able to fix this by adding 'dir' statements in the GDB init file:
dir src
dir src/utils
...
Now it works.