Develop PostgreSQL on Mavericks (OS X 10.9) - c

I'm try to debug PostgreSQL in Eclipse / Netbeans / QtCreator on Mavericks (OS X 10.9).
I have tried various compilers (GCC 4.2, CLang) in the various IDEs, different debuggers (GDB, LLDB), but I haven't found a configuration that works - especially in the sense that I can debug the code properly.
I'm currently trying with GCC 4.2 and GDB. I have installed GCC via homebrew and also certified gdb. I can compile the PostgreSQL source code and run it. However, each time I try to attach the debugger to the running threads, I always (independent of IDE) the following error:
Mach error at "darwin-at.c:726" in function "void darwin_resume_thread(struct inferior *, darwin_thread_t *, int, int)": (os/kern) failure (0x5).
Do you have any ideas what this means? Or do you have maybe a clue how I can get PostgreSQL to compile, debug and run on OS X 10.9?

Use the compiler and debugger from XCode, not one installed from Macports / Homebrew / whatever. Build with llvm and debug with lldb.
You might need to install XCode 5 for this to work on your new OS X.
Apple tends to rather freely break kernel interfaces, etc, when they update the OS, and rarely document these changes for 3rd parties. So it sometimes takes time for 3rd party tools to catch up and work on the latest OS X. In this case it seems reasonably likely that they've messed with the debug interfaces used by gdb.
If you still have issues when using the XCode 5 toolchain, post about that with specifics. The current question is a little bit of everything, so it's hard to pin down details.
Given that this is a Mach error (i.e. the kernel is complaining) it's also possible you've got a 3rd party driver or utility that's causing issues with a hook. Check what kernel extensions you've got installed.

Related

The Linux kernels 3.* series won't boot properly upon being customly compiled in Ubuntu 16.04.1 by means of make-kpkg and gcc-4.8.5

Recently I upgraded up to Ubuntu 16.04.1 Xenial (from 14.04 Trusty) the build-host where I've compiled different linux kernels so far for my own project. Ubuntu 16.04.1 implies using a new updated environment for building binaries. These tools include a new gcc-5.4, libc6 (for userspace applications), etc. Also a new Ubuntu supplies (or suggests) a new kernel-package containing a new make-kpkg script and pulling different dependencies like build-essential, binutils, etc. with it
Ok, my task is to compile a linux kernel v3.10.12 (or v3.19) and run it within a VirtualBox machine (architecture x86_64, system Ubuntu 16.04.1). I used to be able to compile kernel-v3.10.12 and kernel-v3.19 in Ubuntu 14.04 Trusty deployed on the build server with the compiler gcc-4.8 and launch the kernels under the VirtualBox machine I mentioned above, but now something goes wrong while starting a kernel compiled
For example, let's consider v3.10.12 being compiled and run
For building the kernel I utilize 'make-kpkg' script provided by Ubuntu aptitude's package 'kernel-package'. I build the kernel for x86_64 using gcc-4.8 as I have always been doing
Once 'make-kpkg' has compiled the kernel and gathered linux-headers it starts packing them into deb-packages what makes me able to execute 'dpkg -i' on them in the system and install them in a 'debian' way
Okey, supposing I did it. Then I am going to reboot the system
When I choose my compiled kernel in the grub menu, it writes in the screen "Loading linux kernel... Loading initial ramdisk", then the inscription disappears, the screen goes black and I see only a cursor in the form of underscore "_" sign in the top-left side of the screen. That's all. Nothing is going to happen further. The booting process seems to have stuck
I tried swapping make-kpkg for an old one (from Trusty), swapping compiler gcc-4.8.5 for gcc-4.9, gcc-4.7, even gcc-5.2 having made a couple of supplementations inside the directory include/linux/ for the support of gcc-5.2, but nothing has come off, the result still persists being the same
I tried the same actions (on the same Ubuntu 16.04.1 and tool-chain) with new kernels 4. series* (for example, 4.6) meaning building the kernels, packing them into *.deb packages and installing into the VirtualBox machine and rebooting the system, and everything goes correctly, I see debug messages in the screen like I have always seen. I tried to use gcc-4.7, gcc-4.8, gcc-4.9, gcc-5.4 and everything works, I am able to load the linux-kernel-v4.6 appropriately and completely. But when I build 3.10.12 (or 3.19) kernels I cannot boot them properly and cannot have figured out why it has been happening
Actually, what I have found out is that the deal is in the kernel but not in initrd because I managed to substitute the 'broken' kernel by a working one having left 'initrd' built together with the 'broken' kernel and the debug logging started appearing and the kernel was loading until a rootfs came out to be mounted, at that moment the kernel didn't manage to load it and left in initramfs mode
Has someone faced the same issue I am observing? Actually I am almost exhausted having been struggling with this trouble for days
Maybe someone has any recipes or suggestion how to get rid of the problem?
I even put the 'panic' function code exactly in the first line of the function "asmlinkage void __init start_kernel(void)" but nothing happened, still the same black screen
Can the problem be related to a new glibc being used by gcc compiling my kernel? Personally, I am not prone to think so but in the world of linux everything can happen. On the other hand maybe toolchain (ld, as) somehow has affected? I am kindly asking to provide me a help.
I am nearly assured that someone before me has already encountered such an issue, I would have been searching for a topic alike but didn't find anything resembling
Thank you in advance
Short Answer
It's a glibc kernel version mismatch, if you need this you could create the glibc package such that it supports the kernel version that you need, by using the --enable-kernel flag at configuration time.
Long Answer
It's highly likely that your glibc was compiled in such a way that it only works down to a certain version of linux. This is done with the help of the --enable-kernel flag at the configuration stage. Any version older than the one specified in --enable-kernel will be rejected by glibc as a consequence no program will ever be loaded, like the init program presumably systemd's init.
This is from the configuration help of glibc
--enable-kernel=version
This option is currently only
useful on GNU/Linux systems. The version parameter should have the form X.Y.Z and describes the smallest version of the Linux kernel the generated library is expected to support. The higher the version number is, the less compatibility code is added, and the faster the code gets.
Finally I succeeded in this problem
Actually what I have done is to have compiled an old gcc-4.8.5 with an old glibc-2.19 on the host-system where I build the old-versioned kernels.
Glibc-2.19 was compiled with an option --enable-kernel=3.10.12 and with headers of an old-versioned linux-3.10.12. The compiler has turned out to be like a 'cross-compiler' with usage of glibc-2.19. So, I built an old kernel with the version 3.10.12 with this 'cross-compiler', which uses glibc-2.19, and everything has started working in a proper way
Thanks for the help and directing me to a right way to solve the problem, but I am obliged to notice that the deal was in host-system's glibc used but not in target-system glibc used as I had been assumedly said (but maybe I misunderstood #iharob)

Issue with gdb on ubuntu with gcc 4.4.3

i am using gcc 4.4.3 on ubuntu 10.4 32bit machine.
i use 'gdb' to debug my code. Since few days i am seeing that whenever i debug code gdb steps into the c library functions used in the code also(like printf,fgets etc). This shows a long list of calls from one function to other.see the attached screen shot.
Previously gdb was working fine just stepping over my own code.
Maybe i am being novice !! But it is sometimes really irritating when gdb shows me numerous lines which i am not interested in the present context.
If someone can guide me as in how to turn off/on this feature and what can be cause of it being switched on on its own(i don't remember doing anything).
Many thanks.
i used to do that previously also but then it never went into any of the lib functions
You (or someone) have installed libc6-dbg package. Before that, GDB couldn't step into libc functions, because they didn't have any debug info. Now they do, and it can.
Either get out of the habit of typing step when you want next, or un-install libc6-dbg.

Binary compatibility between Linux distributions

Sorry if this is an obvious question, but I've found surprisingly few references on the web ...
I'm working with an API written in C by one of our business partners and supplied to us as a .so binary file, built on Fedora 11. We've been testing out the API on a Fedora 11 development machine with no problems. However, when I try to link against the API on our customer's target platform, which happens to be SuSE Enterprise 10.2, I get a "File format not recognized" error.
Commands that are also part of the binutils package, such as objdump or nm, give me the same file format error. The "file" command shows me:
ELF 64-bit LSB shared object, AMD x86-64, version 1 (SYSV), not stripped
and the "ldd" command shows:
ldd: warning: you do not have execution permission for `./libuscuavactivity.so.1.1'
./libuscuavactivity.so.1.1: /usr/lib64/libstdc++.so.6: version `GLIBCXX_3.4.9' not found (required by ./libuscuavactivity.so.1.1)
[dependent library list]
I'm guessing this is due to incompatibility between the C libraries on the two platforms, with the problem being that the code was compiled against a new version of glibc etc. than the one available on SuSE 10.2. I'm posting this question on the off chance that there is a way to compile the code on our partner's Fedora 11 platform in such a way that it will run on SuSE 10.2 as well.
I think the trick is to build on a flavour of linux with the oldest kernel and C library versions of any of the platforms you wish to support. In my job we build on Debian 4, which allows us to officially support Debian 4 and above, RedHat 3,4,5, SuSE 10 plus various other distros (SELinux etc.) in an unofficial fashion.
I suspect by building on a nice new version of linux, it becomes difficult to support people on older machines.
(edit) I should mention that we use the default compiler that comes with Debian 4, which I think is GCC 4.1.2. Installing newer compiler versions tends to make compatibility much worse.
Windows has it problems with compatability between different realeases, service packs, installed SDKs, and DLLs in general (DLL Hell, anyone?). Linux is not immune to the same kinds of issues.
The compatability issues I have seen include:
Runtime library changes
Link library changes
Kernel changes
Compiler technology changes (eg: pre and post EGCS gcc versions. This might be your issue).
Packager issues (RPM vs. APT)
In your particular case, I'd have them do a "gcc -v" on their system and report to you the gcc version number. Compare that to what you are using.
You might have to get hold of that version of the compiler to build your half with.
You can use Linux Application Checker tool ([1], [2], [3]) in order to solve compatibility problems of an application between Linux distributions. It will check your file formats and all dependent libraries. It supports almost all popular Linux distributions including all versions of SuSE and Fedora.
This is just a personal opinion, but when distributing something in binary-only form on Linux, you have a few options:
Build the gamut of .debs and .rpms for every distro under the sun, with a nominal ".tar.gz full of binaries" package for anything you've missed. The first part is ideal but cumbersome. The latter part will lead you to point 2 and 3.
Do as some are suggesting and find the oldest distro you can find and build there. My own opinion is this is sort of a ridiculous idea. See point 3.
Distribute binaries, and statically link where ever you can. Especially for libstdc++, which appears to be your problem here. There are seemingly very many incompatible versions of libstdc++ floating around, which makes it a compatibility nightmare. If you can't link statically, you can also put *.so files alongside your binary, and use stuff like LD_PRELOAD or LD_LIBRARY_PATH to make them link preferentially at runtime. Note that if you take this route you may have to comply with LGPL etc. since you are now distributing other people's work alongside your project.
Of course, distributing your project in source form is always preferred on Linux. :-)
If the message is file format not recognized then the problem is most likely one mentioned by elmarco in a comment -- namely, different architecture. It might (I'm not sure) be a dynamic linker version mismatch, but that would mean the .so file was built with an ancient dynamic linker. I do not believe any incompatibility in libc could cause this -- they could cause link failures and runtime problems (latter very rarely), but not this.
I don't know about Suse, but I know fedora likes to stay on the bleeding edge. So you may very well be right about library versions. Why don't you ask and see if you can get the source code and build it on your Suse machine?

How to start debugging?

I have learned C and I would like to start to improve open source software. I would like to hack away one irritating bug in GTK+. To see the bug I need to use Gedit.
How can I download the sources of GTK+ and gedit and compile both of them so that I can see where the bug is? And I have never used any debugger in Linux so is there somewhere a tutorial for that?
You can get information about downloading and compiling of gedit here:
http://projects.gnome.org/gedit/developers.html
My Debugger of choice is GDB:
http://www.gnu.org/software/gdb/
GDB is a console application that may be hard to handle for a beginner. Try an IDE like Eclipse that provides a GUI to GDB.
Almost all Linux debuggers are front-ends for or adaptations of the gdb debugger. You should therefore learn how to use this first, preferably by starting on
small programs of your own construction, not giant FOSS codebases. The gdb manual,
available from here is actually a pretty good tutorial.
The information on building and installing GTK+ should be here:
http://www.gtk.org/development.html
The sources should be here:
http://www.gtk.org/download-linux.html
You can check out gdb:
http://www.gnu.org/software/gdb/ That's a pretty standard linux debugger. I would spend time with it on something simple first, or get an IDE that uses it. Learning gdb can be worth the time though.
gdb is a dinosaur which should long since have been made extinct. Debugging is one area where (gasp!) Windows beats Unix. Having got that off my chest, I advise you to start with the Data Display Debugger (DDD) graphical front end to gdb. Yes, the GUI is quaint, but you will be far more productive, quicker, than if you start with gdb.
Also don't overlook valgrind for finding and diagnosing memory errors. The KDE project actually mandates use of valgrind; I'm not sure about Gnome.
It is possible that you won't see the bug if you download the latest gedit and gtk+ sources. It might be fixed in the latest sources or the latest sources might be different enough to not trigger your bug.
What Linux distribution are you running?
First of all I'd suggest consulting your distribution's bug database to see if someone has filed a similar bug. If you don't find anything, I'd suggest using your distribution's tools to obtain the source that corresponds to the binary that you have installed on your sytem (e.g. apt-get source libgtk-2.0 on Debian or Ubuntu).
Also, your distribution might also make a debug package available (e.g. libgtk2.0-0-dbg on Debian) which will let you run a debugger on the binary that you already have without requiring the source. While this is no substitute for having the sources, it can be useful for running valgrind or making sense out of a core file.

How do I cross-compile C code on Windows for a binary to also be run on Unix (Solaris/HPUX/Linux)?

I been looking into Cygwin/Mingw/lcc and I liked to be able to compile perl native C extensions on my windows(preferably under cygwin) and then run them on Solaris and HP unix without any further fuss, is this possible?
This all stems from my original perl cross-platform question here.
(This is a very old question, but missing some useful info --
I've personally done this for Solaris (SPARC & x86), AIX, HP-UX and Linux (x86, x64).)
Getting C++ cross-compiled is much harder than straight C.
HP-UX 32-bit PA-RISC is not supported because it uses SOM format instead of ELF and binutils doesn't (and likely won't ever) support SOM. In other words, you can only cross-compile 64-bit PA-RISC. (Requires PA-RISC 2.0 chip.)
I would go with mingw instead of cygwin, if you can. Cygwin introduces a lot of file permission headaches and cygwin1.dll dependencies that can be troublesome. If possible, however, build on linux. Everything will be much faster because all the tools and scripts you're running are designed for an environment where exec and stat are fast operations. Windows + NTFS is not that environment.
Start with the crosstools script, but be prepared to spend a lot of time on this.
Try with the very latest gcc/binutuils first, but if you can't overcome problems try dropping back to older packages. E.g. for Power3 (AIX) gcc 4.x series cross compiler generates bad code, 3.x is fine.
When copying native libs and headers make sure you are copying from the oldest machine you're likely to run on. Copying a new libc means your code won't run on any machine with an older libc.
When copying native libs and headers you probably want 'tar -h' to turn symlinks into actual files, also watch that on Solaris some requisite crt object files are buried in a cc directory, not under /usr/lib
Cross-compiler are very hard to setup and get working correctly.
Consider that (the people at) NetBSD have to put in a huge amount of work to get cross-compiling to work, and they're running the same OS, just different architectures.
You'd have to, at least, copy all the headers from the other OSs to Windows, and get a cross-compiler, linker etc for the target OS/architecture.
Also that may well not be possible - perl and shared libraries may be compiled with a native/non-gcc compiler which won't be available on Windows at all.
I agree with Douglas, that getting a cross compiler up and working is very hard to do. This is generally, your choice of last resort. If you are boot strapping, or making a binary for an embedded device, then often cross-compiling is your only option. You should be comfortable compiling your own gcc under Cygwin before considering cross compiling. To cross compile, you need to build a gcc to run under windows, but which will create binaries for your execution platform. Sample instructions for doing this can be found here.
Perhaps you are wanting to cross compile because you don't have root and/or can't compile on your target platform. For example, I had a hosting provider which ran Redhat Linux. I could run Perl CGI scripts, and associated modules, but I could not compile on the target machine, and an libraries I built had to exist in my own directory.
To solve this, I could have attempted to cross compile for my target platform, but instead, I decided to setup a similar host inside a VM on Windows. From within Cygwin, you can create a script which ssh's into your VM, copies your source, and does a full configure/build. The last step was to deploy the binary artifact onto my hosted system.
I've successfully had both Solaris 10 and Open Solaris running within a VM on Windows. Unfortunately, you might have a harder time running HPUX under a VM.
Why don't you have a read up on "Grand Unified Builder" (http://lilypond.org/gub/ and http://valentin.villenave.info/The-LilyPond-Report-11 (section #4))
I don't know how it works, but GUB allows the Lilypond developers to compile for about 11 platforms on a linux box.
Compile on Windows then use Wine to run them on any *nix. It works well most of the time.
No, this isn't possible at the binary level. There are so many differences at binary level between the various OSes and CPUs.
But what you can do is make the your C extensions source compatible so that it can compile to different platforms. C was designed as a "portable assembly language". As long as you stick with routines that are cross-platform, then they will usually work the same. You'll still need to test because there could be bugs that exists on particular platform.
This can't be done ... but is it that much of a hassle to recompile the code under Solaris or HP?

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