git: bdf0f24bb16d - main - linux: implement PTRACE_GET_SYSCALL_INFO

[Konstantin Belousov]

On Tue, Sep 14, 2021 at 08:41:06PM +0000, Edward Tomasz Napierala wrote:
> The branch main has been updated by trasz:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=bdf0f24bb16d556a5b1e01cdfc087d08e91ac572
> 
> commit bdf0f24bb16d556a5b1e01cdfc087d08e91ac572
> Author:     Edward Tomasz Napierala <trasz at FreeBSD.org>
> AuthorDate: 2021-09-12 11:31:10 +0000
> Commit:     Edward Tomasz Napierala <trasz at FreeBSD.org>
> CommitDate: 2021-09-14 20:19:55 +0000
> 
>     linux: implement PTRACE_GET_SYSCALL_INFO
>     
>     This is one of the pieces required to make modern (ie Focal)
>     strace(1) work.
>     
>     Reviewed By:    jhb (earlier version)
>     Sponsored by:   EPSRC
>     Differential Revision:  https://reviews.freebsd.org/D28212
> ---
>  lib/libsysdecode/mktables             |  2 +-
>  sys/amd64/linux/linux_ptrace.c        | 98 +++++++++++++++++++++++++++++++++--
>  sys/compat/freebsd32/freebsd32_misc.c |  3 ++
>  sys/kern/sys_process.c                | 17 ++++++
>  sys/sys/ptrace.h                      |  4 ++
>  5 files changed, 120 insertions(+), 4 deletions(-)
> 
> +	case PT_GET_SC_ARGS_ALL:
> +		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS_ALL: pid %d", p->p_pid);
> +		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
> +#ifdef COMPAT_FREEBSD32
> +		    || (wrap32 && !safe)
> +#endif
> +		    ) {
> +			error = EINVAL;
> +			break;
> +		}
> +		bcopy(td2->td_sa.args, addr, sizeof(td2->td_sa.args));
> +		break;

This is awful, you already got that feedback in review, as I read it.
I strongly suggest to remove PT_GET_SC_ARGS_ALL, and instead checks something
in the implementation of PT_GET_SC_ARGS to select either full copy or just
nargs args.

Easiest thing for 'something' would be SV_PROC_ABI(p) == SV_ABI_LINUX.