On Mon, Jul 11, 2011 at 06:12:15PM +0200, Petr Salinger wrote: > >I would instead use a new flag to specify a signal sent on the child > >death. Like RFTSIGZMB. If flag is not set, SIGCHLD is used. If it is > >set, the bit slice is used as signal number, 0 means do not send any > >signal. > > > >Please note that the signal should be checked for validity, it must be > ><= _SIG_MAXSIG). > > We used this: > > #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) > > Therefore signal #128 (_SIG_MAXSIG) cannot be selected. > > Should the bit slice be 7 or 8 bits ?
I propose to go 8 bits, and add the check to be future-proof. It seems that we already parse GNU/kFreeBSD brandnote. I think this could be used to distinguish between old behaviour, that is currently used by your libc, and proposed new interface, if __FreeBSD_version is bumped and honored by glibc. You might need to store the brandinfo somewhere in struct proc or use the separate struct sysentvec.
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