On Sun, Sep 17, 2023 at 10:39 PM Karim Taha <kariem.taha...@gmail.com>
wrote:
> From: Stacey Son <s...@freebsd.org>
>
> Signed-off-by: Stacey Son <s...@freebsd.org>
> Signed-off-by: Karim Taha <kariem.taha...@gmail.com>
> Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
> ---
> bsd-user/freebsd/os-proc.h | 39 +++++++++++++++++++++++++++++++++++
> bsd-user/freebsd/os-syscall.c | 4 ++++
> 2 files changed, 43 insertions(+)
>
Reviewed-by: Warner Losh <i...@bsdimp.com>
> diff --git a/bsd-user/freebsd/os-proc.h b/bsd-user/freebsd/os-proc.h
> index 14478d4bb5..a406ef7db8 100644
> --- a/bsd-user/freebsd/os-proc.h
> +++ b/bsd-user/freebsd/os-proc.h
> @@ -212,4 +212,43 @@ static inline abi_long do_freebsd_vfork(void *cpu_env)
> return do_freebsd_fork(cpu_env);
> }
>
> +/* rfork(2) */
> +static inline abi_long do_freebsd_rfork(void *cpu_env, abi_long flags)
> +{
> + abi_long ret;
> + abi_ulong child_flag;
> +
> + /*
> + * XXX We need to handle RFMEM here, as well. Neither are safe to
> execute
> + * as-is on x86 hosts because they'll split memory but not the stack,
> + * wreaking havoc on host architectures that use the stack to store
> the
> + * return address as both threads try to pop it off. Rejecting
> RFSPAWN
> + * entirely for now is ok, the only consumer at the moment is
> posix_spawn
> + * and it will fall back to classic vfork(2) if we return EINVAL.
> + */
> + if ((flags & TARGET_RFSPAWN) != 0) {
> + return -TARGET_EINVAL;
> + }
> + fork_start();
> + ret = rfork(flags);
> + if (ret == 0) {
> + /* child */
> + child_flag = 1;
> + target_cpu_clone_regs(cpu_env, 0);
> + } else {
> + /* parent */
> + child_flag = 0;
> + }
> +
> + /*
> + * The fork system call sets a child flag in the second return
> + * value: 0 for parent process, 1 for child process.
> + */
> + set_second_rval(cpu_env, child_flag);
> + fork_end(child_flag);
> +
> + return ret;
> +
> +}
> +
> #endif /* BSD_USER_FREEBSD_OS_PROC_H */
> diff --git a/bsd-user/freebsd/os-syscall.c b/bsd-user/freebsd/os-syscall.c
> index cb9425c9ba..4c4e773d1d 100644
> --- a/bsd-user/freebsd/os-syscall.c
> +++ b/bsd-user/freebsd/os-syscall.c
> @@ -234,6 +234,10 @@ static abi_long freebsd_syscall(void *cpu_env, int
> num, abi_long arg1,
> ret = do_freebsd_vfork(cpu_env);
> break;
>
> + case TARGET_FREEBSD_NR_rfork: /* rfork(2) */
> + ret = do_freebsd_rfork(cpu_env, arg1);
> + break;
> +
> case TARGET_FREEBSD_NR_execve: /* execve(2) */
> ret = do_freebsd_execve(arg1, arg2, arg3);
> break;
> --
> 2.42.0
>
>
