On Fri, Mar 1, 2024 at 6:17 PM Robert Engels <reng...@ix.netcom.com> wrote:
>
> The could be calling fork() as in the system call - which copies all file
> descriptors but I didn’t think Go processes could fork.
>
> Seems you would need to remap stdin and stdout in the fork to do anything
> useful.
>
> This sounds very PHP - what goes around comes around.
Good point, I am assuming that the OP is using the os/exec package to
start up a new copy of the process.
A simple fork without an exec can't work in Go, or in any
multi-threaded program.
Ian
> > On Mar 1, 2024, at 8:01 PM, Ian Lance Taylor <i...@golang.org> wrote:
> >
> > On Fri, Mar 1, 2024 at 5:57 PM Jeff Stein <jeffst...@gmail.com> wrote:
> >>
> >> I'm struggling to understand if I'm able to do something.
> >>
> >>
> >> In my very odd use case we are writing a websever that handles connections
> >> via a forked process.
> >>
> >> I have a listener process that listens for TCP connections.
> >>
> >> So each net.Conn that comes in we pull off its file descriptor:
> >>
> >> fd, err := conn.(*net.TCPConn).File()
> >>
> >> duplicate that file descriptor and then fork off a process passing in that
> >> file descriptor.
> >>
> >> In my forked handler I'll reconstruct the HTTP connection and "do stuff".
> >>
> >> The concern I'm having is that it appears when I fork a process I inherit
> >> all of the parent file descriptors so if I have say 5 incoming connections
> >> and then I fork my child process technically could write to a different
> >> connection.
> >>
> >> I've played around with the various options:
> >>
> >> cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: false,}
> >>
> >> and using cmd.ExtraFiles
> >>
> >> No matter what I do I seem unable to limit the sub process to ONLY using
> >> the specific File Descriptor I want it to have access to.
> >>
> >> I believe this is doable in C - but I'm not sure if I can do this in
> >> GoLang as-is without mods .
> >
> > What you are describing shouldn't happen. A child process should only
> > get the file descriptors explicitly passed via the os/exec.Cmd fields
> > Stdin, Stdout, Stderr, and ExtraFiles. So tell us more: OS and
> > version of Go, and what is showing you that all file descriptors are
> > being passed down to the child.
> >
> > Ian
> >
> > --
> > You received this message because you are subscribed to the Google Groups
> > "golang-nuts" group.
> > To unsubscribe from this group and stop receiving emails from it, send an
> > email to golang-nuts+unsubscr...@googlegroups.com.
> > To view this discussion on the web visit
> > https://groups.google.com/d/msgid/golang-nuts/CAOyqgcUb27YBCyE52QisHLyB9XPPpEycMxt4FrFJogGsFMiemQ%40mail.gmail.com.
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/golang-nuts/CAOyqgcWYFJarW%3D%3DsGPC771-syZavevFTV9P1uzx59PL81eVFhw%40mail.gmail.com.
