Le 02/10/2024 à 10:08, Ilya Leoshkevich a écrit :
On Fri, 2024-08-30 at 15:36 -0700, Noah Goldstein wrote:
The new option '-qemu-children' makes it so that on `execve` the
child
process will be launch by the same `qemu` executable that is
currently
running along with its current commandline arguments.
The motivation for the change is to make it so that plugins running
through `qemu` can continue to run on children. Why not just
`binfmt`?: Plugins can be desirable regardless of system/architecture
emulation, and can sometimes be useful for elf files that can run
natively. Enabling `binfmt` for all natively runnable elf files may
not be desirable.
Another reason to have this is that one may not have root permissions
to configure binfmt-misc.
A little note on that: binfmt_misc is now part of the user namespace (since linux v6.7), so you can
configure binfmt_misc as a non root user in a given namepace.
There is helper to use it with unshare from util-linux, you can do things like
that:
With 'F' flag, load the interpreter from the initial namespace:
$ /bin/qemu-m68k-static --version
qemu-m68k version 8.2.2 (qemu-8.2.2-1.fc40)
Copyright (c) 2003-2023 Fabrice Bellard and the QEMU Project developers
$ unshare --map-root-user --fork --pid
--load-interp=":qemu-m68k:M::\\x7fELF\\x01\\x02\\x01\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x02\\x00\\x04:\\xff\\xff\\xff\\xff\\xff\\xff\\xfe\\x00\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xfe\\xff\\xff:/bin/qemu-m68k-static:OCF"
--root=chroot/m68k/sid
# QEMU_VERSION= ls
qemu-m68k version 8.2.2 (qemu-8.2.2-1.fc40)
Copyright (c) 2003-2023 Fabrice Bellard and the QEMU Project developers
# /qemu-m68k --version
qemu-m68k version 8.0.50 (v8.0.0-340-gb1cff5e2da95)
Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project developers
Without 'F' flag, from inside the namespace:
$ unshare --map-root-user --fork --pid
--load-interp=":qemu-m68k:M::\\x7fELF\\x01\\x02\\x01\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x02\\x00\\x04:\\xff\\xff\\xff\\xff\\xff\\xff\\xfe\\x00\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xfe\\xff\\xff:/qemu-m68k:OC"
--root=chroot/m68k/sid
# QEMU_VERSION= ls
qemu-m68k version 8.0.50 (v8.0.0-340-gb1cff5e2da95)
Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project developers
# /qemu-m68k --version
qemu-m68k version 8.0.50 (v8.0.0-340-gb1cff5e2da95)
Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project developers
Thanks,
Laurent
