ldd for busybox compiled for arm

[Yegor Yefremov]

Hi Vered!

do you need ldd on your host or on the target too? On target you can use:

LD_TRACE_LOADED_OBJECTS=1 <executable>

to get dependencies, so no need to cross-compile and install ldd.

Yegor

On 05.01.2017 04:34, Vered Zvi wrote:
> 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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