sd-rtnl: introduce sd_rtnl_new_from_netlink

src/libsystemd/sd-rtnl/sd-rtnl.c

@@ -67,6 +67,31 @@ static int sd_rtnl_new(sd_rtnl **ret) {
         return 0;
 }
 
+int sd_rtnl_new_from_netlink(sd_rtnl **ret, int fd) {
+        _cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL;
+        socklen_t addrlen;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_rtnl_new(ret);
+        if (r < 0)
+                return r;
+
+        addrlen = sizeof(rtnl->sockaddr);
+
+        r = getsockname(fd, &rtnl->sockaddr.sa, &addrlen);
+        if (r < 0)
+                return -errno;
+
+        rtnl->fd = fd;
+
+        *ret = rtnl;
+        rtnl = NULL;
+
+        return 0;
+}
+
 static bool rtnl_pid_changed(sd_rtnl *rtnl) {
         assert(rtnl);
 
@@ -126,7 +151,7 @@ static int rtnl_open_fd_ap(sd_rtnl **ret, int fd, unsigned n_groups, va_list ap)
 
         r = getsockname(fd, &rtnl->sockaddr.sa, &addrlen);
         if (r < 0)
-                return r;
+                return -errno;
 
         rtnl->fd = fd;
 

src/systemd/sd-rtnl.h

@@ -41,6 +41,7 @@ typedef struct sd_rtnl_message sd_rtnl_message;
 typedef int (*sd_rtnl_message_handler_t)(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata);
 
 /* bus */
+int sd_rtnl_new_from_netlink(sd_rtnl **nl, int fd);
 int sd_rtnl_open(sd_rtnl **nl, unsigned n_groups, ...);
 int sd_rtnl_open_fd(sd_rtnl **nl, int fd, unsigned n_groups, ...);
 int sd_rtnl_inc_rcvbuf(const sd_rtnl *const rtnl, const int size);