diff --git a/SheepShaver/src/Unix/Darwin/paranoia.cpp b/SheepShaver/src/Unix/Darwin/paranoia.cpp
new file mode 100755
index 00000000..957f94d7
--- /dev/null
+++ b/SheepShaver/src/Unix/Darwin/paranoia.cpp
@@ -0,0 +1,162 @@
+/*
+ *  paranoia.cpp - Check undocumented features of the Darwin kernel that
+ *                 SheepShaver relies upon
+ *
+ *  SheepShaver (C) 1997-2004 Christian Bauer and Marc Hellwig
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/ucontext.h>
+
+#include "sysdeps.h"
+#include "main.h"
+#include "user_strings.h"
+
+#define DEBUG 1
+#include "debug.h"
+
+
+// Constants
+const uint32 SIG_STACK_SIZE = 0x10000;		// Size of signal stack
+
+// Prototypes
+extern "C" int sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss);
+extern "C" void *get_sp(void);
+extern "C" void set_r2(uint32 val);
+extern void paranoia_check(void);
+static void sigusr2_handler(int sig, siginfo_t *sip, void *scp);
+
+// Global variables
+static void *sig_stack = NULL;
+
+static int err = 0;
+static void *sig_sp = NULL;
+static void *sig_r4 = NULL;
+static int sig_sc_signal = 0;
+static void *sig_sc_regs = NULL;
+static uint32 sig_r2 = 0;
+
+
+void paranoia_check(void)
+{
+	char str[256];
+
+	D(bug("Paranoia checks...\n"));
+
+	// Create and install stack for signal handler
+	sig_stack = malloc(SIG_STACK_SIZE);
+	if (sig_stack == NULL) {
+		ErrorAlert(GetString(STR_NOT_ENOUGH_MEMORY_ERR));
+		exit(1);
+	}
+
+	struct sigaltstack old_stack;
+	struct sigaltstack new_stack;
+	new_stack.ss_sp = (char *)sig_stack;
+	new_stack.ss_flags = 0;
+	new_stack.ss_size = SIG_STACK_SIZE;
+	if (sigaltstack(&new_stack, &old_stack) < 0) {
+		sprintf(str, GetString(STR_SIGALTSTACK_ERR), strerror(errno));
+		ErrorAlert(str);
+		exit(1);
+	}
+
+	// Install SIGUSR2 signal handler
+	static struct sigaction old_action;
+	static struct sigaction sigusr2_action;
+	sigemptyset(&sigusr2_action.sa_mask);
+	sigusr2_action.sa_sigaction = sigusr2_handler;
+	sigusr2_action.sa_flags = SA_ONSTACK | SA_RESTART | SA_SIGINFO;
+	if (sigaction(SIGUSR2, &sigusr2_action, &old_action) < 0) {
+		sprintf(str, GetString(STR_SIGUSR2_INSTALL_ERR), strerror(errno));
+		ErrorAlert(str);
+		exit(1);
+	}
+
+	// Raise SIGUSR2
+	set_r2(0xaffebad5);
+	raise(SIGUSR2);
+
+	// Check error code
+	switch (err) {
+		case 1:
+			printf("FATAL: sigaltstack() doesn't seem to work (sp in signal handler was %08lx, expected %08lx..%08lx)\n", (uint32)sig_sp, (uint32)sig_stack, (uint32)sig_stack + SIG_STACK_SIZE);
+			break;
+		case 2:
+			printf("FATAL: r4 in signal handler (%08lx) doesn't point to stack\n", (uint32)sig_r4);
+			break;
+		case 3:
+			printf("FATAL: r4 in signal handler doesn't seem to point to a ucontext_t (signal number was %d, expected %d)", sig_sc_signal, SIGUSR2);
+			break;
+		case 4:
+			printf("FATAL: sc->regs in signal handler (%08lx) doesn't point to stack\n", (uint32)sig_sc_regs);
+			break;
+		case 5:
+			printf("FATAL: sc->regs->gpr[2] in signal handler (%08lx) doesn't have expected value (%08x)\n", (uint32)sig_r2, 0xaffebad5);
+			break;
+	}
+	if (err) {
+		printf("Maybe you need a different kernel?\n");
+		exit(1);
+	}
+
+	// Clean up
+	D(bug("...passed\n"));
+	sigaction(SIGUSR2, &old_action, NULL);
+	sigaltstack(&old_stack, NULL);
+	free(sig_stack);
+}
+
+
+static void sigusr2_handler(int sig, siginfo_t *sip, void *scp)
+{
+	ucontext_t *ucp = (ucontext_t *)scp;
+
+	// Check whether sigaltstack works
+	sig_sp = get_sp();
+	if (sig_sp < sig_stack || sig_sp >= ((uint8 *)sig_stack + SIG_STACK_SIZE)) {
+		err = 1;
+		return;
+	}
+
+	// Check whether r4 points to info on the stack
+	sig_r4 = ucp;
+	if (sig_r4 < sig_stack || sig_r4 >= ((uint8 *)sig_stack + SIG_STACK_SIZE)) {
+		err = 2;
+		return;
+	}
+
+	// Check whether context regs points to info on the stack
+	sig_sc_regs = &ucp->uc_mcontext->ss.r0;
+	if (sig_sc_regs < sig_stack || sig_sc_regs >= ((uint8 *)sig_stack + SIG_STACK_SIZE)) {
+		err = 4;
+		return;
+	}
+
+	// Check whether r2 still holds the value we set it to
+	sig_r2 = ucp->uc_mcontext->ss.r2;
+	if (sig_r2 != 0xaffebad5) {
+		err = 5;
+		return;
+	}
+}