Rework kern_semctl a bit to always assume the UIO_SYSSPACE case. This

mostly consists of pushing a few copyin's and copyout's up into
__semctl() as all the other callers were already doing the UIO_SYSSPACE
case.  This also changes kern_semctl() to set the return value in a passed
in pointer to a register_t rather than td->td_retval[0] directly so that
callers can only set td->td_retval[0] if all the various copyout's succeed.

As a result of these changes, kern_semctl() no longer does copyin/copyout
(except for GETALL/SETALL) so simplify the locking to acquire the semakptr
mutex before the MAC check and hold it all the way until the end of the
big switch statement.  The GETALL/SETALL cases have to temporarily drop it
while they do copyin/malloc and copyout.  Also, simplify the SETALL case to
remove handling for a non-existent race condition.

1 files changed, 1 insertions, 1 deletions

diff --git a/sys/sys/syscallsubr.h b/sys/sys/syscallsubr.h
index c7a0cd5..faf6f93 100644
--- a/sys/sys/syscallsubr.h
+++ b/sys/sys/syscallsubr.h
@@ -126,7 +126,7 @@ int	kern_rmdir(struct thread *td, char *path, enum uio_seg pathseg);
 int	kern_sched_rr_get_interval(struct thread *td, pid_t pid,
 	    struct timespec *ts);
 int	kern_semctl(struct thread *td, int semid, int semnum, int cmd,
-	    union semun *arg, enum uio_seg bufseg);
+	    union semun *arg, register_t *rval);
 int	kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
 	    fd_set *fd_ex, struct timeval *tvp);
 int	kern_sendfile(struct thread *td, struct sendfile_args *uap,