Re: [PATCH v2 3/3] nbd: disable signals and forking on Windows builds

[Eric Blake]

On 9/2/20 5:07 PM, 罗勇刚(Yonggang Luo) wrote:
> On Tue, Aug 25, 2020 at 6:40 PM Daniel P. Berrangé <berrange@redhat.com>
> wrote:
>
> > Disabling these parts are sufficient to get the qemu-nbd program
> > compiling in a Windows build.
> >
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> >   meson.build | 7 ++-----
> >   qemu-nbd.c  | 5 +++++
> >   2 files changed, 7 insertions(+), 5 deletions(-)

> > +++ b/qemu-nbd.c
> > @@ -899,6 +899,7 @@ int main(int argc, char **argv)
> >   #endif
> >
> >       if ((device && !verbose) || fork_process) {
> > +#ifndef WIN32
> >           int stderr_fd[2];
> >           pid_t pid;
> >           int ret;
> > @@ -962,6 +963,10 @@ int main(int argc, char **argv)
> >                */
> >               exit(errors);
> >           }
> > +#else /* WIN32 */
> > +        error_report("Unable to fork into background on Windows hosts");
> > +        exit(EXIT_FAILURE);
> > +#endif /* WIN32 */
> >       }
> May us replace fork with alternative such as spawn?

You're certainly welcome to propose a patch along those lines, if 
spawning a task is a common Windows counterpart to the Unix notion of 
forking off a daemon.  But even requiring qemu-nbd to run in the 
foreground is already an improvement over what we had previously, so any 
change to use spawn will be a separate series, and will not hold up this 
one.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org