support SOCK_CLOEXEC on macOS

compat/Makefile.am

@@ -29,6 +29,8 @@ endif
 libcompat_la_SOURCES =
 libcompat_la_LIBADD = $(PLATFORM_LDADD)
 
+libcompat_la_SOURCES += socket.c
+
 if !HAVE_ADJFREQ
 if HOST_FREEBSD
 libcompat_la_SOURCES += adjfreq_freebsd.c

compat/socket.c

@@ -0,0 +1,29 @@
+#define SOCKET_FLAGS_PRIV
+
+#include <sys/socket.h>
+
+#ifdef NEED_SOCKET_FLAGS
+
+#include <fcntl.h>
+
+int
+_socket(int domain, int type, int protocol)
+{
+	int s = socket(domain, type & ~(SOCK_CLOEXEC | SOCK_NONBLOCK), protocol);
+	int flags;
+	if (s == -1)
+		return s;
+
+	if (type & SOCK_CLOEXEC) {
+		flags = fcntl(s, F_GETFD);
+		fcntl(s, F_SETFD, flags | FD_CLOEXEC);
+	}
+
+	if (type & SOCK_NONBLOCK) {
+		flags = fcntl(s, F_GETFL);
+		fcntl(s, F_SETFL, flags | O_NONBLOCK);
+	}
+	return s;
+}
+
+#endif

include/sys/socket.h

@@ -11,6 +11,15 @@
 	 ((struct sockaddr*)(X))->sa_family == AF_INET6 ? sizeof(struct sockaddr_in6) : \
 	 ((struct sockaddr*)(X))->sa_family == AF_UNSPEC ? sizeof(struct sockaddr) : \
 	   sizeof(struct sockaddr))
+#endif
+
+#if !defined(SOCK_NONBLOCK) || !defined(SOCK_CLOEXEC)
+#define NEED_SOCKET_FLAGS
+int _socket(int domain, int type, int protocol);
+#ifndef SOCKET_FLAGS_PRIV
+#define socket(d, t, p) _socket(d, t, p)
+#endif
+#endif
 
 /*
  * Prevent Solaris 10 system header leakage
@@ -19,4 +28,10 @@
 #undef MODEMASK
 #endif
 
+#ifndef SOCK_NONBLOCK
+#define	SOCK_NONBLOCK		0x4000	/* set O_NONBLOCK */
+#endif
+
+#ifndef SOCK_CLOEXEC
+#define	SOCK_CLOEXEC		0x8000	/* set FD_CLOEXEC */
 #endif