sockets: move fd_is_socket() into common sockets code

The fd_is_socket() helper method is useful in a few places, so put it in
the common sockets code. Make the code more compact while moving it.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

include/qemu/sockets.h

@@ -12,6 +12,7 @@ int inet_aton(const char *cp, struct in_addr *ia);
 #include "qapi/qapi-types-sockets.h"
 
 /* misc helpers */
+bool fd_is_socket(int fd);
 int qemu_socket(int domain, int type, int protocol);
 int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen);
 int socket_set_cork(int fd, int v);

io/channel-util.c

@@ -24,19 +24,6 @@
 #include "io/channel-socket.h"
 
 
-static bool fd_is_socket(int fd)
-{
-    int optval;
-    socklen_t optlen;
-    optlen = sizeof(optval);
-    return qemu_getsockopt(fd,
-                           SOL_SOCKET,
-                           SO_TYPE,
-                           (char *)&optval,
-                           &optlen) == 0;
-}
-
-
 QIOChannel *qio_channel_new_fd(int fd,
                                Error **errp)
 {

tests/.gitignore

@@ -86,6 +86,7 @@ test-thread-pool
 test-throttle
 test-timed-average
 test-uuid
+test-util-sockets
 test-visitor-serialization
 test-vmstate
 test-write-threshold

tests/Makefile.include

@@ -146,6 +146,7 @@ ifneq (,$(findstring qemu-ga,$(TOOLS)))
 check-unit-$(CONFIG_LINUX) += tests/test-qga$(EXESUF)
 endif
 check-unit-y += tests/test-timed-average$(EXESUF)
+check-unit-y += tests/test-util-sockets$(EXESUF)
 check-unit-y += tests/test-io-task$(EXESUF)
 check-unit-y += tests/test-io-channel-socket$(EXESUF)
 check-unit-y += tests/test-io-channel-file$(EXESUF)
@@ -713,6 +714,8 @@ tests/test-crypto-tlscredsx509$(EXESUF): tests/test-crypto-tlscredsx509.o \
 tests/test-crypto-tlssession.o-cflags := $(TASN1_CFLAGS)
 tests/test-crypto-tlssession$(EXESUF): tests/test-crypto-tlssession.o \
 	tests/crypto-tls-x509-helpers.o tests/pkix_asn1_tab.o $(test-crypto-obj-y)
+tests/test-util-sockets$(EXESUF): tests/test-util-sockets.o \
+	tests/socket-helpers.o $(test-util-obj-y)
 tests/test-io-task$(EXESUF): tests/test-io-task.o $(test-io-obj-y)
 tests/test-io-channel-socket$(EXESUF): tests/test-io-channel-socket.o \
         tests/io-channel-helpers.o tests/socket-helpers.o $(test-io-obj-y)

tests/test-util-sockets.c

@@ -0,0 +1,77 @@
+/*
+ * Tests for util/qemu-sockets.c
+ *
+ * Copyright 2018 Red Hat, Inc.
+ *
+ * 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 library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qemu/sockets.h"
+#include "qapi/error.h"
+#include "socket-helpers.h"
+
+static void test_fd_is_socket_bad(void)
+{
+    char *tmp = g_strdup("qemu-test-util-sockets-XXXXXX");
+    int fd = mkstemp(tmp);
+    if (fd != 0) {
+        unlink(tmp);
+    }
+    g_free(tmp);
+
+    g_assert(fd >= 0);
+
+    g_assert(!fd_is_socket(fd));
+    close(fd);
+}
+
+static void test_fd_is_socket_good(void)
+{
+    int fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
+
+    g_assert(fd >= 0);
+
+    g_assert(fd_is_socket(fd));
+    close(fd);
+}
+
+int main(int argc, char **argv)
+{
+    bool has_ipv4, has_ipv6;
+
+    socket_init();
+
+    g_test_init(&argc, &argv, NULL);
+
+    /* We're creating actual IPv4/6 sockets, so we should
+     * check if the host running tests actually supports
+     * each protocol to avoid breaking tests on machines
+     * with either IPv4 or IPv6 disabled.
+     */
+    if (socket_check_protocol_support(&has_ipv4, &has_ipv6) < 0) {
+        return 1;
+    }
+
+    if (has_ipv4) {
+        g_test_add_func("/util/socket/is-socket/bad",
+                        test_fd_is_socket_bad);
+        g_test_add_func("/util/socket/is-socket/good",
+                        test_fd_is_socket_good);
+    }
+
+    return g_test_run();
+}

util/qemu-sockets.c

@@ -91,6 +91,14 @@ NetworkAddressFamily inet_netfamily(int family)
     return NETWORK_ADDRESS_FAMILY_UNKNOWN;
 }
 
+bool fd_is_socket(int fd)
+{
+    int optval;
+    socklen_t optlen = sizeof(optval);
+    return !qemu_getsockopt(fd, SOL_SOCKET, SO_TYPE, &optval, &optlen);
+}
+
+
 /*
  * Matrix we're trying to apply
  *