Sorry,

the status was "scheduled", because tag "Hostarch: x86_64" was missing in Project config of that project.

It does not deal with qemu-accel at all.

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

*From:* Илья Палачев <[email protected]>
*Sent:* Wednesday, July 30, 2014 7:41PM
*To:* Alexander Graf <[email protected]>, Ilya Palachev
*Cc:* [email protected] <[email protected]>
*Subject:* Re: [opensuse-arm] How does package "qemu-accel" work?

Hi, again..

I have a problem during the build at build.tizen.org related with qemu-accel 
package. The cross build for armv7l architecture is based on qemu-accel 
package. It was imported from opensuse (some time ago).

Now the problem is that packages in "armv7l" in our project is staying in "scheduled" 
state for a long time (while most of workers are in idle state) and this happens only package 
"qemu-accel" is based in current repository. If we use usual version of qemu-accel (without my 
modifications) packages begin to build.

Can wrong build of "qemu-accel" package cause the obs scheduler to hang?

Best regards,
Ilya

15.07.2014, 16:00, "Alexander Graf" <[email protected]>:

On 07/15/2014 01:45 PM, Ilya Palachev wrote:
  Hi, all.

  I have found that package "qemu-accel-armv7l-cross-arm" contains
  directory /emul/i586-for-arm/ with cross utilities that accelerate the
  build.

  Could you explain, how does this construction work?

  For example, there are 2 binaries in the chroot environemt:

  bash-4.2# file /usr/bin/make
  /usr/bin/make: ELF 32-bit LSB executable, ARM, version 1 (SYSV),
  dynamically linked (uses shared libs), for GNU/Linux 2.6.16,
  BuildID[sha1]=0xe1ed5cff83cb3973a9b8ed363857cd796dba63cf, not stripped
  bash-4.2# file /emul/i586-for-arm/usr/bin/make
  /emul/i586-for-arm/usr/bin/make: ELF 32-bit LSB executable, Intel
  80386, version 1 (SYSV), dynamically linked (uses shared libs), for
  GNU/Linux 2.6.16,
  BuildID[sha1]=0x90f51594906fdc9f7906c7e119ba8703a616d4b8, not stripped
  bash-4.2# whereis make
  make: /usr/bin/make /usr/share/man/man1/make.1.gz
  bash-4.2# LD_DEBUG=all make 2>&1 | tail -10
       27438: binding file make [0] to /emul/i586-for-arm/lib/libc.so.6
  [0]: normal symbol `exit' [GLIBC_2.0]
       27438: symbol=ferror;  lookup in file=make [0]
       27438: symbol=ferror;  lookup in
  file=/emul/i586-for-arm/lib/libc.so.6 [0]
       27438: binding file make [0] to /emul/i586-for-arm/lib/libc.so.6
  [0]: normal symbol `ferror' [GLIBC_2.0]
       27438: symbol=fclose;  lookup in file=make [0]
       27438: symbol=fclose;  lookup in
  file=/emul/i586-for-arm/lib/libc.so.6 [0]
       27438: binding file make [0] to /emul/i586-for-arm/lib/libc.so.6
  [0]: normal symbol `fclose' [GLIBC_2.1]
       27438:
       27438: calling fini: make [0]
       27438:

  "whereis" says that "make" is taken from /usr/bin/, but ld.so says
  that it is taken from /emul/i586-for-arm/usr/bin/, so we have cross
  accelerated executable "make".

  How does this work?
ARM binaries don't run natively on x86. So instead when we see an ARM
binary, we execute a binfmt_misc handler instead. Our binfmt_misc
handler (qemu-arm-binfmt) checks whether /emul/i586-for-arm/$0 exists.
If it does, it executes that one. If it doesn't, it calls qemu-arm with $@.

For the glorious details, check out

https://github.com/openSUSE/qemu/blob/opensuse-2.1/linux-user/binfmt.c

Alex

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