How to write Hello World for OpenWRT and/or dd-wrt - openwrt

Question

I'm working on running a Hello World program on the Linksys WRT54G-V4 running either dd-wrt or OpenWRT.
Right now this router is running dd-wrt for reasons I'll explain below. I'd like to switch this router to OpenWRT, because I've not been able to build dd-wrt or its toolchain. I 'assume' that the OpenWRT toolchain should produce executable binaries that will run on dd-wrt also.
OpenWRT was pretty straightforward to build, since it has a nice menu driven make system. Using this handy tool I built a toolchain that will cross compile from my x86 Ubuntu box to a MIPS target.
Following the instructions I've been able to build OpenWRT and produce images for brcm47xx and brcm63xx.
For example, here is a successful compile of my little Hello World program:
jim#ubuntu:~/Desktop/tests$ cat helloC.c
#include <stdio.h>
int main (int argc, char **argv)
{
printf("Hello World\n");
return 0;
}
jim#ubuntu:~/Desktop/tests$
jim#ubuntu:~/Desktop/tests$ mipsel-openwrt-linux-gcc -o HelloWorld helloC.c
jim#ubuntu:~/Desktop/tests$
jim#ubuntu:~/Desktop/tests$ file HelloWorld
HelloWorld: ELF 32-bit LSB executable, MIPS, MIPS32 version 1, dynamically linked (uses shared libs), with unknown capability 0xf41 = 0x756e6700, with unknown capability 0x70100 = 0x3040000, not stripped
jim#ubuntu:~/Desktop/tests$
Sadly, when I try to run HelloWorld on my WRT54G-V4 running dd-wrt I get a seg fault.
Looking at Wikipedia, I see that this router uses the Broadcom BCM5352.
When I run make menuconfig in by OpenWRT/trunk directory I don't see an option for the BCM5352, which is why I'm reluctant to flash my router with one of the images I've created in the brcm47xx or brcm63xx directories. I don't want to guess wrong and brick the router.
Question 1 - Which Broadcom configuration should I select using make menuconfig to target my WRT54G-V4 with its BCM5352 chipset?
Question 2 - Should my 'HelloWorld' executable file I generated above run directly from the command line on the 54G, or must I make it a package per http://www.gargoyle-router.com/wiki/doku.php?id=openwrt_coding ?
TIA

Answer 1

You can follow the official howto (from: http://www.dd-wrt.com/forum/viewtopic.php?p=21499&sid=de90601a8d51747d1c8ccec29284127d)
1. The helloworld.c source
Code:
#include <stdio.h>
int main ( void ) {
printf( "Hello world!\n" );
}
2. Get and unpack the toolchain in your homedir
Code:
cd ~
wget ftp://ftp.dd-wrt.com/sourcecode/toolchains.x86.debian.sp1.tar.bz2
tar -jxf toolchains.x86.debian.sp1.tar.bz2
3. Add the path to your cross-compiler executable to your path environment variable and compile helloworld.c
Code:
PATH=~/toolchains/4.1.0-uclibc-0.9.28/bin:$PATH mipsel-linux-uclibc-gcc helloworld.c -o helloworld
4. Check if its correctly compiled with the cross-compiler
Code:
file helloworld
helloworld: ELF 32-bit LSB executable, MIPS, version 1 (SYSV), dynamically linked (uses shared libs), not stripped
5. Finally, transfer the helloworld binary file to your router, set the executable bit and run it.
Tested with Ubuntu 6.06.1 LTS.