Remotely debugging a Linux process from Windows with gdb and gdbserver: what exactly is needed on the Windows side?

20
votes

I am running Eclipse CDT on Windows to develop C code that is built & tested on remote Linux systems. Currently, the code is never compiled on Windows.

I am able to use CDT to begin the remote process on the Linux target under gdbserver, and then attach gdb from the Windows host. However, gdb immediately fails with errors like:

warning: A handler for the OS ABI "GNU/Linux" is not built into this configuration
of GDB.  Attempting to continue with the default i386 settings.
[...]
Remote 'g' packet reply is too long: 74afe9bff0aee9bf02000000f4af4a00a0aee9bf[...]

Debugging between two Linux systems works fine, so it's clear that I'm doing something wrong on the Windows host side. My specific questions are:

  • Is the Cygwin version of gdb sufficient to debug remote Linux processes, or do I need a special cross-gdb in order to run it on Windows and work with Linux processes? If so, is there anywhere can I get hold of such a gdb?

  • Remote debugging with gdb requires that symbols are available on the host system. What is the easiest way to achieve this? Can I just copy the symbols produced by the build on the Linux target to the Windows host, or do have to get a full build going on Windows? Is there a way to avoid this requirement, such that I can supply symbols only on the target?

Thanks,

-R

More info: The RSE FAQ provides some pointers, but unfortunately I'm still blocked. The FAQ describes two approaches:

  • Launch the gdb client on the remote system over ssh. Problem here is that certain fields in the CDT debug launcher are tied to the local system (project path, executable path etc...).
  • Build/obtain a cross-debugging version of gdb that supports debugging Linux processes from Windows. Problem here is that there's little info on how to achieve this.

I have also raised this issue on the CDT forum.

6
windowslinuxgdbeclipse-cdtgdbserver

6 Answers

0
votes

Setting up a cross-compile or cross-debug environment with gcc/gdb is a very difficult problem, and it's almost never the most efficient solution. Putting a linux VM on your windows box, and debugging there, will be much less work. If you need, really, to debug 'over there', I'd suggest just ssh-ing and using command-line gdb. If you can't have source over there, remote-debugging from a linux VM under your control would be practical.

9
votes

Just rebuild gdb with target platform supporting. You can use Cygwin for this. Example for RHEL target platform:

> wget http://ftp.gnu.org/gnu/gdb/gdb-<ver>.tar.xz
> tar -xJvf gdb-<ver>.tar.xz
> mkdir -p gdb-<ver>/build/x86_64-redhat-linux-gnu
> cd gdb-<ver>/build/x86_64-redhat-linux-gnu
> ../../configure --target=x86_64-redhat-linux-gnu
> make && make install
> x86_64-redhat-linux-gnu-gdb.exe --version

Don't forget to reconfigure your toolchain after this. To obtain the target configuration name, you can use:

> echo ${BASH_VERSINFO[5]}
5
votes

Now there is a plugin http://marketplace.eclipse.org/content/direct-remote-c-debugging

Which allows you to launch gdb on the server remotely over ssh. It takes care about path mapping and others things.

You don't need gdb server to be running remotely

2
votes

I failed to build on Windows, but found quite easy building it under Linux. To summarize and complete @Eugene response: First, prepare sources:

wget http://ftp.gnu.org/gnu/gdb/gdb-<ver>.tar.xz
tar -xJvf gdb-<ver>.tar.xz
mkdir -p gdb-<ver>/build/x86_64-redhat-linux-gnu
cd gdb-<ver>/build/x86_64-redhat-linux-gnu

Download Windows compiler:

sudo apt-get install mingw-w64

Check out the target configuration platform you want to debug your binaries (what to put in --target parameter):

echo ${BASH_VERSINFO[5]}

Prepare makefiles targeted for your desired platform but running on different host. We compiling it static so that it doesn't depend on any DLLs or other libraries. Also we disabling building other binaries as gdb wiki suggests: 

../../configure --host=x86_64-w64-mingw32 --target=x86_64-pc-linux-gnu --enable-static=yes --disable-interprocess-agent --disable-binutils --disable-ld --disable-gold --disable-gas --disable-sim --disable-gprof

finally, build (takes like 30-60 min):

make LDFLAGS=-static

You can find your debugger in gdb folder. It is also good to strip it of debugging symbols as after building executable is huge:

strip -s gdb/gdb.exe

Voila! gdb.exe ready to run in Windows and remotely debug Linux executables!

1
votes

Visual Studio Community Edition 2017 features GDB cross-compiling and debugging tools. Couple this with a Linux server or the Windows Linux sub-system and you can reliably develop C code for Linux systems. check out this guide.

0
votes

Software development is generally much easier on linux than it is on windows. But that's off topic.

What is important when you debug cross compiled binaries is that you use gdb from cross compiler - not host gdb. You can not for example use gdb built for windows to debug a linux process (well you can but it is not recommended). You need to use the cross compiler gdb to debug the remote process (which is part of the same toolchain that was used to build the binary). As you are saying that you never compile on windows, I'm pretty certain this could be your problem. The easiest way for you to get it working is to just use the gdb from command line on the remote machine, where you compile, and do your debugging over ssh.