os: wrap socket(SOCK_CLOEXEC) calls

Some system C libraries do not offer SOCK_CLOEXEC flag.

Add a new header for OS compatibility wrappers. Wrap socket() calls into
wl_os_socket_cloexec() which makes sure the O_CLOEXEC flag gets set on
the file descriptor.

On systems having SOCK_CLOEXEC this uses the old socket() call, and
falls back if it fails due to the flag (kernel not supporting it).

wayland-os.h is private and not exported.

Add close-on-exec tests for both normal and forced fallback paths.

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

5 files changed, 104 insertions, 2 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 7217236..c685885 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -14,6 +14,8 @@ libwayland_util_la_SOURCES =			\
 	connection.c				\
 	wayland-util.c				\
 	wayland-util.h				\
+	wayland-os.c				\
+	wayland-os.h				\
 	wayland-private.h
 
 libwayland_server_la_LIBADD = $(FFI_LIBS) libwayland-util.la -lrt
diff --git a/src/wayland-client.c b/src/wayland-client.c
index 713c894..794f716 100644
--- a/src/wayland-client.c
+++ b/src/wayland-client.c
@@ -36,6 +36,7 @@
 #include <sys/poll.h>
 
 #include "wayland-util.h"
+#include "wayland-os.h"
 #include "wayland-client.h"
 #include "wayland-private.h"
 
@@ -307,7 +308,7 @@ connect_to_socket(struct wl_display *display, const char *name)
 	const char *runtime_dir;
 	size_t name_size;
 
-	display->fd = socket(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
+	display->fd = wl_os_socket_cloexec(PF_LOCAL, SOCK_STREAM, 0);
 	if (display->fd < 0)
 		return -1;
 
diff --git a/src/wayland-os.c b/src/wayland-os.c
new file mode 100644
index 0000000..5ff4391
--- /dev/null
+++ b/src/wayland-os.c
@@ -0,0 +1,69 @@
+/*
+ * Copyright © 2012 Collabora, Ltd.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "wayland-os.h"
+
+static int
+set_cloexec_or_close(int fd)
+{
+	long flags;
+
+	if (fd == -1)
+		return -1;
+
+	flags = fcntl(fd, F_GETFD);
+	if (flags == -1)
+		goto err;
+
+	if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1)
+		goto err;
+
+	return fd;
+
+err:
+	close(fd);
+	return -1;
+}
+
+int
+wl_os_socket_cloexec(int domain, int type, int protocol)
+{
+	int fd;
+
+#ifdef SOCK_CLOEXEC
+	errno = 0;
+	fd = socket(domain, type | SOCK_CLOEXEC, protocol);
+	if (fd >= 0)
+		return fd;
+	if (errno != EINVAL)
+		return -1;
+#endif
+
+	fd = socket(domain, type, protocol);
+	return set_cloexec_or_close(fd);
+}
diff --git a/src/wayland-os.h b/src/wayland-os.h
new file mode 100644
index 0000000..49adc2b
--- /dev/null
+++ b/src/wayland-os.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright © 2012 Collabora, Ltd.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#ifndef WAYLAND_OS_H
+#define WAYLAND_OS_H
+
+int
+wl_os_socket_cloexec(int domain, int type, int protocol);
+
+#endif
diff --git a/src/wayland-server.c b/src/wayland-server.c
index 8ca27bd..1fe00a9 100644
--- a/src/wayland-server.c
+++ b/src/wayland-server.c
@@ -44,6 +44,7 @@
 #include "wayland-private.h"
 #include "wayland-server.h"
 #include "wayland-server-protocol.h"
+#include "wayland-os.h"
 
 struct wl_socket {
 	int fd;
@@ -970,7 +971,7 @@ wl_display_add_socket(struct wl_display *display, const char *name)
 	if (s == NULL)
 		return -1;
 
-	s->fd = socket(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
+	s->fd = wl_os_socket_cloexec(PF_LOCAL, SOCK_STREAM, 0);
 	if (s->fd < 0) {
 		free(s);
 		return -1;