[PATCH v3 1/1] os: added the -upstart option for Upstart's signaling method.

[oliver.mcfadden at nokia.com]

----- Original message -----
> On Wed, Jul 14, 2010 at 07:49:39AM +0300, Oliver McFadden wrote:
> > This is very similar to the RunFromSmartParent (implicit) option,
> except
> > we do not send the signal to our parent process, but our own process
> > instead, and that signal is SIGSTOP, not SIGUSR1.
> > 
> > Upstart will detect this, realize that we are ready to accept clients
> > now, send us SIGCONT and move our job status from SPAWNED to RUNNING.
> > 
> > Signed-off-by: Oliver McFadden <oliver.mcfadden at nokia.com>
> > ---
> > v3: resend patch because it seems to have been idle for some time...
> > - changed kill(getpid()) to raise().
> 
> this seems rather oddly named to me. Ok, upstart may use this one now
> but
> are any of the proposed alternatives using similar methods? (systemd
> maybe?) 
> 
> might be better to use a more descriptive flag like "-sigstop" that
> describes what we actually do instead of hooking it onto a caller's
> name.
> solves two future problems: 
> - if upstart changes the signaling method we don't have a need for a
>     -upstart2, -upstart3 flag
> - if others use similar methods, you don't have to start with -upstart
> for
>     systemd
> both outcomes would be rather confusing, imo.

Ok, this makes sense. I'll send an updated patch once I get back to the office.

> 
> Cheers,
>     Peter
> 
> > include/opaque.h |       1 +
> > os/connection.c   |       5 +++++
> > os/utils.c             |       5 +++++
> > 3 files changed, 11 insertions(+), 0 deletions(-)
> > 
> > diff --git a/include/opaque.h b/include/opaque.h
> > index b3c7c70..f8c0000 100644
> > --- a/include/opaque.h
> > +++ b/include/opaque.h
> > @@ -55,6 +55,7 @@ extern _X_EXPORT int defaultBackingStore;
> > extern _X_EXPORT Bool disableBackingStore;
> > extern _X_EXPORT Bool enableBackingStore;
> > extern _X_EXPORT Bool PartialNetwork;
> > +extern _X_EXPORT Bool RunFromUpstart;
> > #ifndef NOLOGOHACK
> > extern _X_EXPORT int logoScreenSaver;
> > #endif
> > diff --git a/os/connection.c b/os/connection.c
> > index c143fb6..53f7f8c 100644
> > --- a/os/connection.c
> > +++ b/os/connection.c
> > @@ -146,6 +146,8 @@ Bool NewOutputPending;                       /* not yet
> attempted to write some new output */
> > Bool AnyClientsWriteBlocked; /* true if some client blocked on write
> */
> > 
> > static Bool RunFromSmartParent;           /* send SIGUSR1 to parent
> process */
> > +Bool RunFromUpstart;                 /* send SIGSTOP to our own process;
> > +                                                               Upstart will send SIGCONT back. */
> > Bool PartialNetwork; /* continue even if unable to bind all addrs */
> > static Pid_t ParentProcess;
> > 
> > @@ -357,6 +359,9 @@ NotifyParentProcess(void)
> > kill (ParentProcess, SIGUSR1);
> > }
> > }
> > +       if (RunFromUpstart) {
> > +         raise (SIGSTOP);
> > +       }
> > #endif
> > }
> > 
> > diff --git a/os/utils.c b/os/utils.c
> > index 51455cc..f176af4 100644
> > --- a/os/utils.c
> > +++ b/os/utils.c
> > @@ -527,6 +527,7 @@ void UseMsg(void)
> > #endif
> > ErrorF("-dumbSched                         Disable smart scheduling, enable
> old behavior\n");
> > ErrorF("-schedInterval int         Set scheduler interval in msec
> \n");
> > +       ErrorF("-upstart                             Enable support for Upstart's
> signaling method\n");
> > ErrorF("+extension name               Enable extension\n");
> > ErrorF("-extension name               Disable extension\n");
> > #ifdef XDMCP
> > @@ -922,6 +923,10 @@ ProcessCommandLine(int argc, char *argv[])
> > else
> > UseMsg ();
> > }
> > +         else if ( strcmp( argv[i], "-upstart") == 0)
> > +         {
> > +                 RunFromUpstart = TRUE;
> > +         }
> > else if ( strcmp( argv[i], "+extension") == 0)
> > {
> > if (++i < argc)
> > -- 
> > 1.7.1.245.g7c42e
>