While building iw version 3.11 (which has an Android.mk file already), I encountered some issues due to missing/ wrong headers and libraries. Since it has an Android.mk file, the NDK can be used.
In the following I will assume the following:
- A device image has been built before (the kernel headers and libnl-2 static library should at least be available). I have built CyanogenMod 10 (with kernel 3.0.something) for the i9300, update the paths below to reflect that.
- The NDK is installed to
~/android/system/ndk
.
- The NDK has appropriate platforms and toolchains installed.
Preparation after extracting iw-3.11.tar.xz
and changing my directory in it:
ln -s . jni
ln -nsv ~/android/system/external ./
The next issue is the netlink library:
In file included from external/libnl-headers/netlink/genl/genl.h:15:0,
from /tmp/and/iw/jni/iw.c:17:
external/libnl-headers/netlink/netlink.h:27:29: fatal error: linux/genetlink.h: No such file or directory.
Simply creating a link to the android/system/out/target/product/i9300/obj/KERNEL_OBJ/usr/include/linux
breaks other headers badly which will give errors such as:
Compile thumb : iw <= iw.c
In file included from /home/user/android/system/ndk/platforms/android-14/arch-arm/usr/include/net/if.h:28:0,
from /tmp/and/iw/jni/iw.c:10:
/tmp/and/iw/jni/linux/if.h:178:19: error: field 'ifru_addr' has incomplete type
/tmp/and/iw/jni/linux/if.h:179:19: error: field 'ifru_dstaddr' has incomplete type
/tmp/and/iw/jni/linux/if.h:180:19: error: field 'ifru_broadaddr' has incomplete type
/tmp/and/iw/jni/linux/if.h:181:19: error: field 'ifru_netmask' has incomplete type
/tmp/and/iw/jni/linux/if.h:182:20: error: field 'ifru_hwaddr' has incomplete type
In file included from external/libnl-headers/netlink/netlink.h:20:0,
from external/libnl-headers/netlink/genl/genl.h:15,
from /tmp/and/iw/jni/iw.c:17:
/home/user/android/system/ndk/platforms/android-14/arch-arm/usr/include/sys/socket.h:74:44: warning: 'struct msghdr' declared inside parameter list [enabled by default]
/home/user/android/system/ndk/platforms/android-14/arch-arm/usr/include/sys/socket.h:74:44: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
/home/user/android/system/ndk/platforms/android-14/arch-arm/usr/include/sys/socket.h:75:38: warning: 'struct msghdr' declared inside parameter list [enabled by default]
In file included from external/libnl-headers/netlink/netlink.h:25:0,
from external/libnl-headers/netlink/genl/genl.h:15,
from /tmp/and/iw/jni/iw.c:17:
/tmp/and/iw/jni/linux/netlink.h:33:2: error: unknown type name 'sa_family_t'
In file included from external/libnl-headers/netlink/genl/genl.h:15:0,
from /tmp/and/iw/jni/iw.c:17:
external/libnl-headers/netlink/netlink.h:51:16: warning: 'struct msghdr' declared inside parameter list [enabled by default]
external/libnl-headers/netlink/netlink.h:54:19: warning: 'struct iovec' declared inside parameter list [enabled by default]
make: *** [/tmp/and/iw/obj/local/armeabi/objs/iw/iw.o] Error 1
A workaround is to create the linux
directory and put a symlink to ~/android/system/out/target/product/i9300/obj/KERNEL_OBJ/usr/include/linux/genetlink.h
in it:
mkdir -p linux
ln -svn ~/android/system/out/target/product/i9300/obj/KERNEL_OBJ/usr/include/linux/genetlink.h linux/
Finally patch Android.mk
to finish linking to the netlink library:
sed "/LOCAL_LDFLAGS/s#\$# -L$HOME/android/system/out/target/product/i9300/obj/STATIC_LIBRARIES/libnl_2_intermediates -lnl_2#" -i Android.mk
Now the build can be started:
NDK_PROJECT_PATH=$PWD ~/android/system/ndk/ndk-build TARGET_PLATFORM=android-14
It will not complete because netlink/genl/genl.h cannot be found, but the iw
binary is available in libs/armeabi!