+#endif /* COMPAT_43 || COMPAT_SUNOS */
+
+struct sigaltstack_args {
+ struct sigaltstack *nss;
+ struct sigaltstack *oss;
+};
+/* ARGSUSED */
+sigaltstack(p, uap, retval)
+ struct proc *p;
+ register struct sigaltstack_args *uap;
+ int *retval;
+{
+ struct sigacts *psp;
+ struct sigaltstack ss;
+ int error;
+
+ psp = p->p_sigacts;
+ if ((psp->ps_flags & SAS_ALTSTACK) == 0)
+ psp->ps_sigstk.ss_flags |= SA_DISABLE;
+ if (uap->oss && (error = copyout((caddr_t)&psp->ps_sigstk,
+ (caddr_t)uap->oss, sizeof (struct sigaltstack))))
+ return (error);
+ if (uap->nss == 0)
+ return (0);
+ if (error = copyin((caddr_t)uap->nss, (caddr_t)&ss, sizeof (ss)))
+ return (error);
+ if (ss.ss_flags & SA_DISABLE) {
+ if (psp->ps_sigstk.ss_flags & SA_ONSTACK)
+ return (EINVAL);
+ psp->ps_flags &= ~SAS_ALTSTACK;
+ psp->ps_sigstk.ss_flags = ss.ss_flags;
+ return (0);
+ }
+ if (ss.ss_size < MINSIGSTKSZ)
+ return (ENOMEM);
+ psp->ps_flags |= SAS_ALTSTACK;
+ psp->ps_sigstk= ss;
+ return (0);
+}