Re: Building minimal rootfs to use as non-root on arm device

[Corbin Champion <corbinlc@gmail.com>]

>> I have created a rootfs using buildroot, but using a crosstool-ng toolchain
>> with glibc.  This showed me the minimal set of files necessary.  I then
>> replaced all the libraries with ones pulled straight from the squeeze .deb
>> packages for armel.

>Hmm. If the problem was to find out the minimal set of files, wouldn't
>grip dependencies do the same?

Good point.  This issue, dns not working, also occurred when doing a full debootstrap (fakechroot variant), but that is also different. 

>> Entering the same setup, but using qemu and chroot on my host machine
>> works

>Are "using qemu and chroot" two distinct test cases?

No.  I copied qemu_arm_static to /usr/bin and used chroot to make this my root.  So, I was on an x86 machine, but used chroot with qemu to emulate being on an arm device with the given root. 

>> When I run "*strace ping google.com*" I get the following:

> Is this on the target?

Yes

>> *open("/data/local/target/bin/ping", O_RDONLY) = 3*

> If yes, how is the rootfs mounted, and what is /data/local/target?

fakechroot is what I use and /data/local/target is the location that I want to be my root.

I use this command:
/data/local/target/usr/bin/fakeroot-sysv -f /data/local/target/usr/bin/faked-sysv -l /data/local/target/usr/lib/libfakeroot/libfakeroot-sysv.so /data/local/target/usr/bin/fakechroot -l /data/local/target/usr/lib/fakechroot/libfakechroot.so /data/local/target/usr/sbin/chroot /data/local/target ash

>> *open("/etc/resolv.conf", O_RDONLY)      = -1 ENOENT (No such file or
>> directory)*
>...
>> *connect(3, {sa_family=AF_INET, sin_port=htons(53),
>> sin_addr=inet_addr("127.0.0.1"

)}, 16) = 0*
>...
>> *open("/data/local/target/etc/hosts", O_RDONLY|O_CLOEXEC) = 3*
>...

>> it figured out that
>> the host file wasn't simply at /etc/hosts, but why do you think it didn't
>> look in the correct location for nsswitch.conf and resolv.conf?

>The fastest way to answer your question would probably be to look at your
>implementation of gethostbyname & Co.

I don't implement these.  libc uses fopen to open these files and I thought fakechroot should modify the path that it is looking for them.  It does that in other cases.  Trying to figure out why this specifically is not working. 

>Do you mean that the correct location should be
>/data/local/target/etc/resolv.conf? If yes, why? What is the problem
>using /etc/resolv.conf?

Yes.  Just like it knew to add /data/local/target to the beginning of where it was looking for the hosts file.  This is because I have run fakechroot. 

>With kind regards,
>Baurzhan.

Thanks,
Corbin