libbb: move netlink socket binding to the utility function

function                                             old     new   delta
create_and_bind_to_netlink                             -     134    +134
ifplugd_main                                        1117    1052     -65
uevent_main                                          399     306     -93
mdev_main                                            314     215     -99
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/3 up/down: 134/-257)         Total: -123 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 8 insertions, 20 deletions

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 88c82b6fb..9cb3586f1 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -1225,28 +1225,16 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                 /*
                  * Daemon mode listening on uevent netlink socket.
                  */
-                struct sockaddr_nl sa;
                 int fd;
 
-//TODO: reuse same code in uevent
-                // Subscribe for UEVENT kernel messages
-                sa.nl_family = AF_NETLINK;
-                sa.nl_pad = 0;
-                sa.nl_pid = getpid();
-                sa.nl_groups = 1 << 0;
-                fd = xsocket(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
-                xbind(fd, (struct sockaddr *) &sa, sizeof(sa));
-                close_on_exec_on(fd);
-
-                // Without a sufficiently big RCVBUF, a ton of simultaneous events
-                // can trigger ENOBUFS on read, which is unrecoverable.
-                // Reproducer:
-                //      mdev -d
-                //      find /sys -name uevent -exec sh -c 'echo add >"{}"' ';'
-                //
-                // SO_RCVBUFFORCE (root only) can go above net.core.rmem_max sysctl
-                setsockopt_SOL_SOCKET_int(fd, SO_RCVBUF,      RCVBUF);
-                setsockopt_SOL_SOCKET_int(fd, SO_RCVBUFFORCE, RCVBUF);
+                /* Subscribe for UEVENT kernel messages */
+                /* Without a sufficiently big RCVBUF, a ton of simultaneous events
+                 * can trigger ENOBUFS on read, which is unrecoverable.
+                 * Reproducer:
+                 *      mdev -d
+                 *      find /sys -name uevent -exec sh -c 'echo add >"{}"' ';'
+                 */
+                fd = create_and_bind_to_netlink(NETLINK_KOBJECT_UEVENT, 1 << 0, RCVBUF);
 
                 /*
                  * Make inital scan after the uevent socket is alive and