Re: Creating a QEmu (x86-64) Image, which can execute binary applications from other x86-64 linux OSes


Christian Lohr <christian.lohr.ext@...>
 

Ok, I created a symbolic link with “ln -s /lib /lib64” and it seemed to work. Thanks a lot.

 

Von: yocto@... <yocto@...> Im Auftrag von Alexander Kanavin
Gesendet: Mittwoch, 12. Februar 2020 12:00
An: Lohr, Christian [ext] <christian.lohr.ext@...>
Cc: yocto@...
Betreff: Re: [yocto] Creating a QEmu (x86-64) Image, which can execute binary applications from other x86-64 linux OSes

 

But this is exactly what happens: the kernel reads the dynamic loader/interpreter path from the binary (which is different than the list of dynamically linked libraries printed by ldd), isn't able to find it and stops right there.

 

Try like this:

 

/lib/ld-linux-x86-64.so.2 /usr/share/dotnet/dotnet

 

Alex

 

 

On Wed, 12 Feb 2020 at 11:45, Lohr, Christian [ext] <christian.lohr.ext@...> wrote:

I used the x86_64 variant from the layer (it only downloads the binaries and copies them).

And I checked that with ldd, it seemed ok so far:

---------------------------------------------------------

root@qemux86-64:/usr/share/dotnet# ldd dotnet

            linux-vdso.so.1 (0x00007fffea543000)

            libpthread.so.0 => /lib/libpthread.so.0 (0x00007f9fde06c000)

            libdl.so.2 => /lib/libdl.so.2 (0x00007f9fde067000)

            libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007f9fddee5000)

            libm.so.6 => /lib/libm.so.6 (0x00007f9fddda4000)

            libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x00007f9fddd8a000)

            libc.so.6 => /lib/libc.so.6 (0x00007f9fddbd0000)

            /lib64/ld-linux-x86-64.so.2 => /lib/ld-linux-x86-64.so.2 (0x00007f9fde097000)

 

Strace didn’t help either:

-------------------------------

root@qemux86-64:/# strace /usr/share/dotnet/dotnet

execve("/usr/share/dotnet/dotnet", ["/usr/share/dotnet/dotnet"], 0x7ffe22f0ab70 /* 22 vars */) = -1 ENOENT (No such file or directory)

strace: exec: No such file or directory

+++ exited with 1 +++

 

It’s strange that it denies that the binaries are there. Normally I would have expected something like “wrong elf architecture” or something about missing libraries. The only thing I think I could do now, is to turn this “—enable-default-pie” off, but I’m not sure if this helps, and I don’t know where to turn it off. And what I’m also trying is to go back to Yocto Rocko Release (for this experiment I used Warrior Release)

 

Von: yocto@... <yocto@...> Im Auftrag von Alexander Kanavin
Gesendet: Mittwoch, 12. Februar 2020 10:26
An: Lohr, Christian [ext] <christian.lohr.ext@...>
Cc: yocto@...
Betreff: Re: [yocto] Creating a QEmu (x86-64) Image, which can execute binary applications from other x86-64 linux OSes

 

That layer does have the x86_64 variant as well, no? Is it not working?

 

The error you're seeing is almost certainly due to Yocto using /lib/ld-so... for dynamic loader, and the binary hardcoding /lib64/....

 

Alex

 

On Wed, 12 Feb 2020 at 10:15, Lohr, Christian [ext] <christian.lohr.ext@...> wrote:

Hello Alex,

 

Thanks for replying. Yes, I know that this isn’t the way it works on Yocto (and I told the managers it is a crappy idea to do that more than once). But they need .NET Core in that company I work for, and Mono doesn’t work (that’s what they told me). Compiling .NET Core through the Yocto process is ugly, because Microsoft used a mixture of shell scripts to compile it for some platforms, it won’t work this way on Yocto. Actually one already tried it, but only until .NET Core 2.2: https://github.com/Tragetaschen/meta-aspnet

And despite this, I already managed to get the dotnet binaries for ARM32 and ARM64 already working on a i.MX6 and i.MX8

There’s a layer which just deploys the binaries: https://github.com/RDunkley/meta-dotnet-core

This is currently the last step. I thought if it worked on i.MX6 and i.MX8 it shouldn’t be a problem to get it running on Virtualbox with x86-64. It should only make the things easy for the developers. It isn’t even our target platform.

 

Best regards,

 

 

Christian Lohr

Von: yocto@... <yocto@...> Im Auftrag von Alexander Kanavin
Gesendet: Mittwoch, 12. Februar 2020 09:51
An: Lohr, Christian [ext] <christian.lohr.ext@...>
Cc: yocto@...
Betreff: Re: [yocto] Creating a QEmu (x86-64) Image, which can execute binary applications from other x86-64 linux OSes

 

Yocto generally does not support this use case. The binary was compiled in a different environment and expects things in different places, and probably being different versions too. I could point out the specific problem why the executable doesn't even start, but it's really the wrong way to approach it. Is the source code for it available?

 

Microsoft specifically lists which distributions are supported, and there is nothing Yocto-based in it:

 

For mono things you can use meta-mono layer, but I am not sure if it provides exactly the item you're after.

 

Alex

 

On Wed, 12 Feb 2020 at 09:36, Christian Lohr <christian.lohr.ext@...> wrote:

Hello,

 

I’m trying to create a normal QEmu (x86-64) Image, which I can let run in Virtualbox. As a addition I deployed .NET Core, which I got from this side:

https://dotnet.microsoft.com/download/dotnet-core/thank-you/runtime-aspnetcore-3.1.1-linux-x64-binaries

 

But I can’t execute it:

----------------------------

root@qemux86-64:/usr/share/dotnet# ./dotnet

-sh: ./dotnet: No such file or directory

 

 

But it is there:

------------------

root@qemux86-64:/usr/share/dotnet# ls -lh

total 116K

-rw-r--r-- 1 root root 1.1K Feb 10 02:33 LICENSE.txt

-rw-r--r-- 1 root root  31K Feb 10 02:33 ThirdPartyNotices.txt

-rwxr-xr-x 1 root root  72K Feb 10 02:33 dotnet

drwxr-xr-x 3 root root 4.0K Feb 10 02:36 host

drwxr-xr-x 4 root root 4.0K Feb 10 02:36 shared

 

 

It tried to get more information about the dotnet-executable

------------------------------------------------------------------------------

root@qemux86-64:/usr/share/dotnet# readelf -h dotnet

ELF Header:

  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00

  Class:                             ELF64

  Data:                              2's complement, little endian

  Version:                           1 (current)

  OS/ABI:                            UNIX - System V

  ABI Version:                       0

  Type:                              EXEC (Executable file)

  Machine:                           Advanced Micro Devices X86-64

  Version:                           0x1

  Entry point address:               0x402f17

  Start of program headers:          64 (bytes into file)

  Start of section headers:          71032 (bytes into file)

  Flags:                             0x0

  Size of this header:               64 (bytes)

  Size of program headers:           56 (bytes)

  Number of program headers:         10

  Size of section headers:           64 (bytes)

  Number of section headers:         31

  Section header string table index: 30

 

root@qemux86-64:/usr/share/dotnet#  file dotnet

dotnet: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=28c244c1953bcbee994709a4b849086ee7cf0c99, stripped

 

 

I compared those values with that from Python, which does run on this system

-------------------------------------------------------------------------------------------------------

root@qemux86-64:/opt/jre-8/bin# readelf -h /usr/bin/python3.7

ELF Header:

  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00

  Class:                             ELF64

  Data:                              2's complement, little endian

  Version:                           1 (current)

  OS/ABI:                            UNIX - System V

  ABI Version:                       0

  Type:                              DYN (Shared object file)

  Machine:                           Advanced Micro Devices X86-64

  Version:                           0x1

  Entry point address:               0x1060

  Start of program headers:          64 (bytes into file)

  Start of section headers:          12568 (bytes into file)

  Flags:                             0x0

  Size of this header:               64 (bytes)

  Size of program headers:           56 (bytes)

  Number of program headers:         11

  Size of section headers:           64 (bytes)

  Number of section headers:         27

  Section header string table index: 26

 

root@qemux86-64:/usr/share/dotnet# file /usr/bin/python3.7

/usr/bin/python3.7: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-x86-64.so.2, BuildID[sha1]=a455873f278466378405802b0e0171337e52a81c, for GNU/Linux 3.2.0, stripped

 

================================================================================

 

The only difference I found, is that Python is a “ELF 64-bit LSB pie executable” whereas dotnet is a “ELF 64-bit LSB executable”. I tried to turn that PIE (seemed to be a gcc option: --enable-default-pie) feature of, but that didn’t work well, and I couldn’t find a way to remove it.

 

 

----

 

Best regards,

 

Christian Lohr

Im Auftrag von:

Carl Zeiss Meditec AG
Göschwitzer Strasse 51-52

07745 Jena, Deutschland

christian.lohr.ext@...

Tel: +493641220206

 

 

 

 

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