thisroot.sh does not recognize bash when running in qemu-x86_64

[kkauder]

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Description

Using a docker container on M1, but not optimized for M1, thisroot.sh extracts the shell name as qemu-x86_64, and consequently produces

ERROR: must "cd where/root/is" before calling ". bin/thisroot.sh" for this version of "qemu-x86_64"!

Reason:
/proc/$$/cmdline produces

/usr/bin/qemu-x86_64
/usr/bin/bash
bash
--norc
...

and cut -d '' -f1 picks up the emulator, not the shell.

Reproducer

I don't know where to find a lighter image, this one isn't too bad at <10 GB. On a Silicon Mac:

curl -L https://github.com/eic/eic-shell/raw/main/install.sh | bash
./eic-shell
source /usr/local/bin/thisroot.sh

I believe in linux the following also invokes the image with a qemu setting

docker run --rm -it --platform linux/arm64 ghcr.io/eic/jug_dev:master-nightly

ROOT version

   ------------------------------------------------------------------
  | Welcome to ROOT 6.28/04                        https://root.cern |
  | (c) 1995-2022, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for linuxx8664gcc on May 08 2023, 02:44:07                 |
  | From tags/v6-28-04@v6-28-04                                      |
  | With g++ (Debian 12.2.0-14) 12.2.0                               |
  | Try '.help'/'.?', '.demo', '.license', '.credits', '.quit'/'.q'  |
   ------------------------------------------------------------------

Installation method

spack

Operating system

Docker container on M1 Mac, inside uname -a = Linux 7163f573db33 5.15.49-linuxkit-pr #1 SMP PREEMPT Thu May 25 07:27:39 UTC 2023 x86_64 GNU/Linux

Additional context

No response

[ferdymercury]

Try maybe adding something like:

if trueExe == qemu-x86_64
trueExe=$(cut -d '' -f2 /proc/$$/cmdline) || return 1
endif

[wdconinc]

The same happens for various other combinations of host and target architectures with qemu. The filename of the emulator doesn't even always include qemu (it's /usr/libexec/qemu-binfmt/aarch64-binfmt-P when emulating aarch64 on x64_64, for example)...

[kkauder]

Is there a reason why ps -p $$ -o comm= isn't used as the default? Cause that seems to work.

[ferdymercury]

Because it failed when calling as executable or with some other platforms (4c9e1e6) #10418

[wdconinc]

Please consider #14251 as a possible fix.