Re: Emulating missing linux syscalls

[Joerg Sonnenberger <joerg%bec.de@localhost>]

Am Tue, Apr 12, 2022 at 12:29:21PM -0000 schrieb Christos Zoulas:
> In article <CALigkZQpW8-wAty57d=hpsx6eo_RmacQ=pkej+FezNS_r6Mq=w%mail.gmail.com@localhost>,
> Piyush Sachdeva  <piyushsachdeva245%gmail.com@localhost> wrote:
> >-=-=-=-=-=-
> >
> >Dear Stephen Borrill,
> >My name is Piyush, and I was looking into the
> >'Emulating missing Linux syscalls' project hoping to contribute
> >to this year's GSoC.
> >
> >I wanted to be sure of a few basic things before I go ahead:
> >- linux binaries are found in- src/sys/compat/linux
> >- particular implementation in - src/sys/compat/linux/common
> >- a few architecture-specific implementations in-
> >  src/sys/compat/linux/arch/<arch_name>.
> >- The src/sys/compat/linux/arch/<arch_name>/linux_syscalls.c file
> >   lists of system calls, and states if a particular syscall is present or
> >not.
> >
> >I was planning to work on the 'sendfile()' syscall, which I believe
> >is unimplemented for amd64 and a few other architectures as well.
> >
> >Considering the above points, I was hoping you could point me in
> >the right direction for this project. Hope to hear from you soon.
> 
> I would look into porting the FreeBSD implementation of sendfile to NetBSD.

sendfile(2) for Linux compat can be emulated in the kernel without
backing. That said, a real splice(2) or even splicev(2) would be really
nice to have. But that's a different project and arguable, a potentially
more generally useful one, too.

Joerg