This patch series implements extended support for the `clone` system
call. As best I can tell, any option combination including `CLONE_VM`
should be supported with the addition of this patch series. The
implementation is described in greater detail in the patches themselves.
Testing:
* All targets built on x86_64.
* `make check` and `make check-tcg` are passing. Additional tests have
been added to `linux-test.c` to validate clone behavior.
Caveats:
* This series touches, but does not fix, several bits of code that are
racey (namely the sigact table and the fd trans table).
* `exit_group` does not perform the appropriate cleanup for non-thread
children created with `CLONE_VM`. CPUs for such children are never
cleaned up. The correct implementation of exit-group is non-trivial
(since it also needs to track/handle cleanup for threads in the
clone'd child process). Also, I don't fully understand the
interaction between QOM<->linux-user. My naive implementation based
on the current implementation `exit(2)` was regularly crashing. If
maintainers have suggestions for better ways to handle exit_group,
they would be greatly appreciated.
* execve does not clean up the CPUs of clone'd children, for the same
reasons as `exit_group`.
Josh Kunz (5):
linux-user: Refactor do_fork to use new `qemu_clone`
linux-user: Make fd_trans task-specific.
linux-user: Make sigact_table part of the task state.
linux-user: Support CLONE_VM and extended clone options
linux-user: Add PDEATHSIG test for clone process hierarchy.
linux-user/Makefile.objs | 2 +-
linux-user/clone.c | 565 ++++++++++++++++++++++++++++
linux-user/clone.h | 27 ++
linux-user/fd-trans-tbl.c | 13 +
linux-user/fd-trans-type.h | 17 +
linux-user/fd-trans.c | 3 -
linux-user/fd-trans.h | 75 ++--
linux-user/main.c | 1 +
linux-user/qemu.h | 49 +++
linux-user/signal.c | 84 ++++-
linux-user/syscall.c | 452 ++++++++++++----------
tests/tcg/multiarch/Makefile.target | 3 +
tests/tcg/multiarch/linux-test.c | 227 ++++++++++-
13 files changed, 1264 insertions(+), 254 deletions(-)
create mode 100644 linux-user/clone.c
create mode 100644 linux-user/clone.h
create mode 100644 linux-user/fd-trans-tbl.c
create mode 100644 linux-user/fd-trans-type.h
--
2.27.0.290.gba653c62da-goog
