os: wrap accept4(SOCK_CLOEXEC)

Some system C libraries do not have SOCK_CLOEXEC, and completely miss
accept4(), too. Provide a fallback for this case.

This changes the behaviour: no error messages are printed now for
failing to set CLOEXEC but the file descriptor is closed.

The unit test for this wrapper is NOT included.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>

5 files changed, 29 insertions, 8 deletions

diff --git a/configure.ac b/configure.ac
index 615dfdb..63081e1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,6 +39,8 @@ if test "x$GCC" = "xyes"; then
 fi
 AC_SUBST(GCC_CFLAGS)
 
+AC_CHECK_FUNCS([accept4])
+
 AC_ARG_ENABLE([scanner],
               [AC_HELP_STRING([--disable-scanner],
                               [Disable compilation of wayland-scannner])],
diff --git a/src/wayland-os.c b/src/wayland-os.c
index a8756b6..1185e1d 100644
--- a/src/wayland-os.c
+++ b/src/wayland-os.c
@@ -20,6 +20,8 @@
  * OF THIS SOFTWARE.
  */
 
+#define _GNU_SOURCE
+
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <unistd.h>
@@ -27,6 +29,7 @@
 #include <errno.h>
 #include <sys/epoll.h>
 
+#include "../config.h"
 #include "wayland-os.h"
 
 static int
@@ -142,3 +145,20 @@ wl_os_epoll_create_cloexec(void)
 	fd = epoll_create(1);
 	return set_cloexec_or_close(fd);
 }
+
+int
+wl_os_accept_cloexec(int sockfd, struct sockaddr *addr, socklen_t *addrlen)
+{
+	int fd;
+
+#ifdef HAVE_ACCEPT4
+	fd = accept4(sockfd, addr, addrlen, SOCK_CLOEXEC);
+	if (fd >= 0)
+		return fd;
+	if (errno != ENOSYS)
+		return -1;
+#endif
+
+	fd = accept(sockfd, addr, addrlen);
+	return set_cloexec_or_close(fd);
+}
diff --git a/src/wayland-os.h b/src/wayland-os.h
index f6827f1..c612975 100644
--- a/src/wayland-os.h
+++ b/src/wayland-os.h
@@ -35,6 +35,9 @@ wl_os_recvmsg_cloexec(int sockfd, struct msghdr *msg, int flags);
 int
 wl_os_epoll_create_cloexec(void);
 
+int
+wl_os_accept_cloexec(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
+
 
 /*
  * The following are for wayland-os.c and the unit tests.
diff --git a/src/wayland-server.c b/src/wayland-server.c
index 94eb308..e8173fb 100644
--- a/src/wayland-server.c
+++ b/src/wayland-server.c
@@ -902,14 +902,8 @@ socket_data(int fd, uint32_t mask, void *data)
 	int client_fd;
 
 	length = sizeof name;
-	client_fd =
-		accept4(fd, (struct sockaddr *) &name, &length, SOCK_CLOEXEC);
-	if (client_fd < 0 && errno == ENOSYS) {
-		client_fd = accept(fd, (struct sockaddr *) &name, &length);
-		if (client_fd >= 0 && fcntl(client_fd, F_SETFD, FD_CLOEXEC) == -1)
-			fprintf(stderr, "failed to set FD_CLOEXEC flag on client fd, errno: %d\n", errno);
-	}
-
+	client_fd = wl_os_accept_cloexec(fd, (struct sockaddr *) &name,
+					 &length);
 	if (client_fd < 0)
 		fprintf(stderr, "failed to accept, errno: %d\n", errno);
 
diff --git a/tests/os-wrappers-test.c b/tests/os-wrappers-test.c
index 967eb83..9c4e7b2 100644
--- a/tests/os-wrappers-test.c
+++ b/tests/os-wrappers-test.c
@@ -382,3 +382,5 @@ TEST(os_wrappers_epoll_create_cloexec_fallback)
 	init_fallbacks(1);
 	do_os_wrappers_epoll_create_cloexec(2);
 }
+
+/* FIXME: add tests for wl_os_accept_cloexec() */