RE: ldd for busybox compiled for arm

[Vered Zvi <veredz@elta.co.il>]

Hi Andy,

Thank you for the detailed reply.

On the host I ran:
cross-compile-ldd  /mydir/boot/rootfs/bin/sh
and got:
libm.so.6 => /lib/libm.so.6 (0xdeadbeef)
libc.so.6 => /lib/libc.so.6 (0xdeadbeef)
ld-linux-armhf.so.3 => /lib/ld-linux-armhf.so.3 (0xdeadbeef)

same result for:
cross-compile-ldd  /mydir/boot/rootfs/sbin/init

I double checked that libm.so.6, libc.so.6 are in /lib

On the host I ran:
file /mydir/boot/roots/bin/busybox
and got:
/mydir//boot/rootfs/bin/busybox: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, BuildID[sha1]=fc40d0187472069db3da93db4b30f9df92a75bbd, stripped

Does it make sense ?

On the host I tried to run /mydir/boot/rootfs/bin/ls.
It runs like the reguar host's ls

Does it make sense ?

I checked:
./arm-cortex_a15-linux-gnueabihf-gcc -v
and got:
COLLECT_GCC=./arm-cortex_a15-linux-gnueabihf-gcc
...
Target: arm-cortex_a15-linux-gnueabihf

Using genext2fs I created a ram disk image from the folder that contains:
/boot /bin/ /sbin/ /usr .....

Upon boot the kernel displays the following error:
/sbin/init exists but couldn't execute it (error -8)
/bin/sh exists but couldn't execute it (error -8)

Can you tell what can cause this error ?
Is it possible that the ramdisk image is not propery created ?

Best regards,
Z.V

________________________________________
From: ANDY KENNEDY [ANDY.KENNEDY@adtran.com]
Sent: Wednesday, January 04, 2017 10:18 PM
To: Vered Zvi; crossgcc@sourceware.org
Subject: RE: ldd for busybox compiled for arm

> -----Original Message-----
> From: crossgcc-owner@sourceware.org [mailto:crossgcc-owner@sourceware.org] On Behalf Of Vered Zvi
> Sent: Tuesday, January 03, 2017 3:49 PM
> To: crossgcc@sourceware.org
> Subject: ldd for busybox compiled for arm
>
>
> Hello,

Hi Vered!

>
> Using crosstool-ng 1.22.0 I created a toolchain for:  arm-cortex_a15-linux-gnueabi
> The host is Centos 7.2.1511 (64)
>
> Using this toolchain I compiled busybox.
> make ARCH=arm CROSS_COMPILE=../../../../toolchain/crosstool/release/bin/arm-cortex_a15-linux-
> gnueabihf- defconfig
> make ARCH=arm CROSS_COMPILE=../../../../toolchain/crosstool/release/bin/arm-cortex_a15-linux-
> gnueabihf-

After doing this, you should have ended up with two files in the
local directory:  busybox busybox_unstripped.

What does "file" return to you for these two files.

>
> Is it possible to use ldd from this toolchain to find out the dependencies for /bin/sh , /sbin/init
> ?
>
> Strange: both /bin/sh, /sbin/init run under x86.

I would hope that to be the case.  /bin/sh on the HOST should not have
been altered by the above steps.  Now, if you mean that you attempted to
run these two commands on the target, this is different.  On target, you
may have to run 'busybox install' to correctly configure the system with
the appropriate links.  The file /bin/busybox on TARGET should be your
NEW busybox prior to executing the install.

If you cannot execute your freshly built busybox on the system (busybox
without options will display the built-ins applets for busybox), you may
have linking issues.  The trick there is that you would many of the libs
that come with the toolchain before this will work.  If you are looking
to build a system without libraries, I suggest that you use BuildRoot
with an internal toolchain to build your busybox statically.

> How it is possible ?
> They were compiled for ARM.
>
> Thank you,
> Z.V

HTH!

Andy

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