The motivation of the implementation is to make the systemd-nspawn container to boot guest OSes with systemd v259+, otherwise any systemd service requires importing credentials will fail, including journald, D-Bus service and getty. We used to work around this issue by patching systemd to retry the clone() without CLONE_NEWNS, which is not and can not be implemented in QEMU user emulation.
mount(8) from util-linux works because it will fallback to the old mount(2) syscall if fsmount(8) series of syscalls is not available. Tested good on an x86-64 host, with: - an AOSC OS mips64r6el guest, which boots successfully with full systemd support using systemd-nspawn(1). - a Gentoo ppc (big endian) guest, which boots successfully with full systemd support, using systemd-nspawn(1). Xinhui Yang (2): linux-user: implement fsmount(2) series of syscalls linux-user/strace: add fsmount series of syscalls linux-user/strace.c | 102 +++++++++++++++++++++++++++++++++++++++++ linux-user/strace.list | 15 ++++++ linux-user/syscall.c | 77 +++++++++++++++++++++++++++++++ 3 files changed, 194 insertions(+) -- 2.52.0
