Hi Johan,
Thanks for the added details.
> The code actually works fine on FreeBSD 7.2 machines. It's also
> fine on OpenBSD (4.7) and MacOS (Darwin 8.11). So it seems something was
> changed / broken in FreeBSD 8.0.
FreeBSD 8.0 has its own, new implementation of the posix_spawn* functions,
whereas on the other platforms the gnulib replacement is used.
> > This quickly identifies a problem:
> >
> > 2143 gm4 CALL sigprocmask(SIG_BLOCK,0x545a20,0)
> > 2143 gm4 RET sigprocmask 0
> > 2143 gm4 CALL vfork
> > 2144 gm4 RET fork 0
> > 2144 gm4 CALL sched_setscheduler(0,<invalid=0>,0x800a0e918)
> > 2144 gm4 RET sched_setscheduler -1 errno 1 Operation not permitted
> > 2144 gm4 CALL exit(0x7f)
> > 2143 gm4 RET vfork 2144/0x860
> > 2143 gm4 CALL sigprocmask(SIG_UNBLOCK,0x545a20,0)
> > 2143 gm4 RET sigprocmask 0
How come that sched_setscheduler is called? The only use of posix_spawn and
posix_spawnp that is made by m4 1.4.14 (see lib/execute.c and lib/pipe.c) is
with a flags value of POSIX_SPAWN_SETSIGMASK. Whereas in the native FreeBSD
posix_spawn[p] (as well as in the gnulib replacement), sched_setscheduler
is only called if the flags word contains the POSIX_SPAWN_SETSCHEDULER bit.
FreeBSD's POSIX_SPAWN_SETSIGMASK is 0x20, FreeBSD's POSIX_SPAWN_SETSCHEDULER
is 0x08. Whereas the gnulib replacement value for POSIX_SPAWN_SETSIGMASK is
0x08. It seems gnulib's replacement value is in use when it should not. I'm
applying this fix.
2010-03-02 Bruno Haible <br...@clisp.org>
spawn: Don't override the system defined values on FreeBSD 8.
* lib/spawn.in.h (POSIX_SPAWN_RESETIDS, POSIX_SPAWN_SETPGROUP,
POSIX_SPAWN_SETSIGDEF, POSIX_SPAWN_SETSIGMASK,
POSIX_SPAWN_SETSCHEDPARAM, POSIX_SPAWN_SETSCHEDULER): Don't redefine
if HAVE_POSIX_SPAWN is 1.
Reported by Johan van Selst <joh...@stack.nl> via Eric Blake.
*** lib/spawn.in.h.orig Tue Mar 2 11:53:02 2010
--- lib/spawn.in.h Tue Mar 2 11:48:54 2010
***************
*** 110,126 ****
/* Flags to be set in the `posix_spawnattr_t'. */
! #if @REPLACE_POSIX_SPAWN@
/* Use the values from the system, for better compatibility. */
/* But this implementation does not support AIX extensions. */
! # undef POSIX_SPAWN_FORK_HANDLERS
! #else
! # define POSIX_SPAWN_RESETIDS 0x01
! # define POSIX_SPAWN_SETPGROUP 0x02
! # define POSIX_SPAWN_SETSIGDEF 0x04
! # define POSIX_SPAWN_SETSIGMASK 0x08
! # define POSIX_SPAWN_SETSCHEDPARAM 0x10
! # define POSIX_SPAWN_SETSCHEDULER 0x20
#endif
/* A GNU extension. Use the next free bit position. */
#define POSIX_SPAWN_USEVFORK \
--- 110,128 ----
/* Flags to be set in the `posix_spawnattr_t'. */
! #if !...@have_posix_spawn@
! # if @REPLACE_POSIX_SPAWN@
/* Use the values from the system, for better compatibility. */
/* But this implementation does not support AIX extensions. */
! # undef POSIX_SPAWN_FORK_HANDLERS
! # else
! # define POSIX_SPAWN_RESETIDS 0x01
! # define POSIX_SPAWN_SETPGROUP 0x02
! # define POSIX_SPAWN_SETSIGDEF 0x04
! # define POSIX_SPAWN_SETSIGMASK 0x08
! # define POSIX_SPAWN_SETSCHEDPARAM 0x10
! # define POSIX_SPAWN_SETSCHEDULER 0x20
! # endif
#endif
/* A GNU extension. Use the next free bit position. */
#define POSIX_SPAWN_USEVFORK \
