DragonFly commits List (threaded) for 2007-01
DragonFly BSD
DragonFly commits List (threaded) for 2007-01
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Re: cvs commit: src/sys/kern kern_sig.c kern_synch.c src/sys/machine/pc32/i386 machdep.c src/sys/machine/vkernel/i386 cpu_regs.c fork_tramp.s trap.c src/sys/machine/vkernel/include globaldata.h md_var.h src/sys/machine/vkernel/platform systimer.c ...

From: Victor Balada Diaz <victor@xxxxxxxxx>
Date: Sun, 14 Jan 2007 12:44:28 +0100

On Sat, Jan 13, 2007 at 11:59:09PM -0800, Matthew Dillon wrote:
> dillon      2007/01/13 23:59:09 PST
> DragonFly src repository
>   Modified files:
>     sys/kern             kern_sig.c kern_synch.c 
>     sys/machine/pc32/i386 machdep.c 
>     sys/machine/vkernel/i386 cpu_regs.c fork_tramp.s trap.c 
>     sys/machine/vkernel/include globaldata.h md_var.h 
>     sys/machine/vkernel/platform systimer.c 
>     sys/sys              proc.h signal.h signalvar.h 
>     sys/vm               vm_vmspace.c 
>   Log:
>   Implement a new signal delivery mechanism, SA_MAILBOX.  If specified the
>   sigaction structure's sa_mailbox pointer (field is unioned with sa_handler)
>   points to a location in user memory.  When the signal occurs, the location
>   is overwritten with the signal number and the next system call made (or
>   the current one running) will return EINTR.  NO SIGNAL STATE IS PUSHED,
>   NO SIGNAL VECTOR IS DISPATCHED.  This makes mailbox signaling very fast.
>   Userland can interlock against the mailbox simply by polling and clearing
>   the mailbox prior to doing a system call.  The mailbox signal will be
>   properly interlocked against the system call.  Userland does not need to
>   make any other system calls (no sigblock() or sigsetmask() calls) to
>   properly interlock delivery.  The kernel interrupts at most one system call
>   per signal delivered via this mechanism, even if the userland does not
>   clear the mailbox.

What happens if a second signal gets delivered to the process before
the first signal is checked by the userland process?

La prueba más fehaciente de que existe vida inteligente en otros
planetas, es que no han intentado contactar con nosotros. 

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