Check kernel structs layout

 sudo pahole -C task_struct /sys/kernel/btf/vmlinux

MacVim with MacPorts and Xcode 7.2 failure

If the install of MacVim with MacPorts fails with error, that says something like this in the log:

"Could not find service "com.apple.CoreSimulator.CoreSimulatorService" in domain ......"

The solution would be change permissions on the: /Applications/Xcode.app/Contents/Developer/Library/PrivateFrameworks/CoreSimulator.framework/Versions/A/XPCServices/com.apple.CoreSimulator.CoreSimulatorService.xpc

with:

sudo chmod g-w com.apple.CoreSimulator.CoreSimulatorService.xpc

Enjoy!

JDK 7 on Mac OS X

It's been some time since I touched Java on Mac OS X, was mostly busy with native (C/C++) cross-platform development recently.
Here is just another note for myself before I forget.

After you install Java 7 on Mac OS X and you try to run java (or javac) it will still pick up the java 1.6 from /System/Library/Java/JavaVirtualMachines/1.6.0.jdk.

In order to fix this go to 

/System/Library/Frameworks/JavaVM.framework/Versions

and remove the CurrentJDK symlink.

Then create the new one to point to the JDK 1.7, in my case with the command:

sudo ln -s /Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/ CurrentJDK

Now check the version: 

$ java -version

java version "1.7.0_79"

.............

Enjoy!

tcpdumping

Just a bookmark for myself, when wireshark is not avail.

This collects the full payload, only from the host  x.x.x.x and https port

and writes into the out.pcap file:

tcpdump -s 0 -w out.pcap -A host x.x.x.x and tcp port https

A useful collection of "gitignores"

https://github.com/github/gitignore

When char bites ...

Got bitten by the char arithmetics in C today, while porting some native code to Android NDK.
Good reminder that the chars are not defined as signed or unsigned in the C standard and treated as unsigned by the ARM compiler for example.
To fix this problem it's better to use either something like int8_t from stdint.h or the compiler flag:
 -funsigned-char

Good luck!

C/C++ macros for the cross platform development

Here are the couple of links that I found very useful for the C/C++ cross-platform development:

http://nadeausoftware.com/articles/2011/12/c_c_tip_how_list_compiler_predefined_macros

http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_system