On Mon, Jul 11, 2011 at 12:54:06PM +0200, Robert Millan wrote: > This patch made by Petr Salinger improves compatibility with > LinuxThreads in rfork() syscall. The Linux clone() implementation > allows specifying the signal sent to parent when child terminates > (instead of SIGCHLD). > > As the threading implementation in Debian GNU/kFreeBSD is > LinuxThreads-based, we had to diverge from upstream kFreeBSD ABI and > implement this extension. > > I hope it is acceptable for you to use the same encoding, this way we > would archieve ABI compatibility to run Debian GNU/kFreeBSD inside a > chroot/jail on top of a FreeBSD system. > > Thanks for considering > > -- > Robert Millan
> --- a/sys/kern/kern_fork.c
> +++ b/sys/kern/kern_fork.c
> @@ -477,7 +477,13 @@
> p2->p_sigacts = newsigacts;
> }
> if (flags & RFLINUXTHPN)
> - p2->p_sigparent = SIGUSR1;
> + {
> + int sig;
> + sig = RFTHPNSIGNUM(flags);
> + if (sig == 0) sig = SIGUSR1;
> + if (sig == SIGCHLD) sig = 0;
> + p2->p_sigparent = sig;
> + }
> else
> p2->p_sigparent = SIGCHLD;
>
> --- a/sys/sys/unistd.h
> +++ b/sys/sys/unistd.h
> @@ -182,6 +182,10 @@
> #define RFHIGHPID (1<<18) /* use a pid higher than 10 (idleproc)
> */
> #define RFPPWAIT (1<<31) /* parent sleeps until child exits
> (vfork) */
> #define RFKERNELONLY (RFSTOPPED | RFHIGHPID | RFPPWAIT)
> +#define RFTHPNSHIFT 24 /* reserve bits 24-30 */
> +#define RFTHPNMASK 0x7F /* for compatibility with linuxthreads/clone()
> */
> + /* allow to specify "clone exit parent
> notification" signal */
> +#define RFTHPNSIGNUM(flags) (((flags) >> RFTHPNSHIFT) & RFTHPNMASK)
>
> #endif /* __BSD_VISIBLE */
>
I looked at this patch some time ago already.
Can you, please, describe the reasoning behind the
> + if (sig == SIGCHLD) sig = 0;
line ?
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