diff --git a/src/main.cpp b/src/main.cpp
index ea30c4d6..29a68ea7 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -18,7 +18,7 @@
 v8::Platform* gPlatform = 0;
 
 void shedPrivileges() {
-#if !defined (_WIN32) && !defined (__MACH__)
+#if !defined (_WIN32)
 	struct rlimit zeroLimit;
 	zeroLimit.rlim_cur = 0;
 	zeroLimit.rlim_max = 0;
@@ -36,19 +36,26 @@ void shedPrivileges() {
 
 	if (setrlimit(RLIMIT_FSIZE, &zeroLimit) != 0) {
 		perror("setrlimit(RLIMIT_FSIZE, {0, 0})");
-	}
-	if (setrlimit(RLIMIT_LOCKS, &zeroLimit) != 0) {
-		perror("setrlimit(RLIMIT_LOCKS, {0, 0})");
-	}
-	if (setrlimit(RLIMIT_MSGQUEUE, &zeroLimit) != 0) {
-		perror("setrlimit(RLIMIT_MSGQUEUE, {0, 0})");
+		exit(-1);
 	}
 	if (setrlimit(RLIMIT_NOFILE, &zeroLimit) != 0) {
 		perror("setrlimit(RLIMIT_NOFILE, {0, 0})");
+		exit(-1);
 	}
 	if (setrlimit(RLIMIT_NPROC, &zeroLimit) != 0) {
 		perror("setrlimit(RLIMIT_NPROC, {0, 0})");
+		exit(-1);
 	}
+#if !defined (__MACH__)
+	if (setrlimit(RLIMIT_LOCKS, &zeroLimit) != 0) {
+		perror("setrlimit(RLIMIT_LOCKS, {0, 0})");
+		exit(-1);
+	}
+	if (setrlimit(RLIMIT_MSGQUEUE, &zeroLimit) != 0) {
+		perror("setrlimit(RLIMIT_MSGQUEUE, {0, 0})");
+		exit(-1);
+	}
+#endif
 #endif
 }
 
diff --git a/tests/02-valgrind b/tests/02-valgrind
index 64c2d6cf..570a567d 100755
--- a/tests/02-valgrind
+++ b/tests/02-valgrind
@@ -1,5 +1,10 @@
 #!/bin/bash
 
+if [ ! -x /usr/bin/valgrind ]; then
+	echo "SKIP"
+	exit 0
+fi
+
 cat > test.js << EOF
 print("hi");
 EOF
diff --git a/tools/run-tests b/tools/run-tests
index 1611d708..8c9c31b5 100755
--- a/tools/run-tests
+++ b/tools/run-tests
@@ -7,7 +7,7 @@ import shutil
 import subprocess
 import sys
 
-if sys.platform != 'linux2':
+if sys.platform not in ('darwin', 'linux2'):
 	print 'Tests are only enabled on Linux.'
 	exit(0)
 
@@ -51,7 +51,10 @@ for test in selectedTests:
 	process = subprocess.Popen(['bash', test], stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=tmp, env=env)
 	stdout, stderr = process.communicate()
 	if process.returncode == 0:
-		print 'PASSED', test
+		if stdout.strip() == "SKIP":
+			print 'SKIPPED', test
+		else:
+			print 'PASSED', test
 		passCount += 1
 	else:
 		print 'FAILED', test