s3:unix_msg: read fds from recvmsg in unix_dgram_recv_handler()

For now we directly close the fds, the next commits will pass them
to the recv_callback function.

Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Michael Adam <obnox@samba.org>

diff --git a/source3/lib/unix_msg/unix_msg.c b/source3/lib/unix_msg/unix_msg.c
index dd2107bd422780460ce888a910332a82375a4162..a5db4170bf328a6df69b5888d6ce622bf52507a3 100644 (file)
--- a/source3/lib/unix_msg/unix_msg.c
+++ b/source3/lib/unix_msg/unix_msg.c
@@ -240,8 +240,15 @@ static void unix_dgram_recv_handler(struct poll_watch *w, int fd, short events,
 {
        struct unix_dgram_ctx *ctx = (struct unix_dgram_ctx *)private_data;
        ssize_t received;
+       int flags = 0;
        struct msghdr msg;
        struct iovec iov;
+#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
+       char buf[CMSG_SPACE(sizeof(int)*INT8_MAX)] = { 0, };
+       struct cmsghdr *cmsg;
+#endif /* HAVE_STRUCT_MSGHDR_MSG_CONTROL */
+       int *fds = NULL;
+       size_t i, num_fds = 0;
 
        iov = (struct iovec) {
                .iov_base = (void *)ctx->recv_buf,
@@ -252,12 +259,16 @@ static void unix_dgram_recv_handler(struct poll_watch *w, int fd, short events,
                .msg_iov = &iov,
                .msg_iovlen = 1,
 #ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-               .msg_control = NULL,
-               .msg_controllen = 0,
+               .msg_control = buf,
+               .msg_controllen = sizeof(buf),
 #endif
        };
 
-       received = recvmsg(fd, &msg, 0);
+#ifdef MSG_CMSG_CLOEXEC
+       flags |= MSG_CMSG_CLOEXEC;
+#endif
+
+       received = recvmsg(fd, &msg, flags);
        if (received == -1) {
                if ((errno == EAGAIN) ||
                    (errno == EWOULDBLOCK) ||
@@ -273,6 +284,44 @@ static void unix_dgram_recv_handler(struct poll_watch *w, int fd, short events,
                /* More than we expected, not for us */
                return;
        }
+
+#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
+       for(cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
+           cmsg = CMSG_NXTHDR(&msg, cmsg))
+       {
+               void *data = CMSG_DATA(cmsg);
+
+               if (cmsg->cmsg_type != SCM_RIGHTS) {
+                       continue;
+               }
+               if (cmsg->cmsg_level != SOL_SOCKET) {
+                       continue;
+               }
+
+               fds = (int *)data;
+               num_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof (int);
+               break;
+       }
+#endif
+
+       for (i = 0; i < num_fds; i++) {
+               int err;
+
+               err = prepare_socket_cloexec(fds[i]);
+               if (err != 0) {
+                       goto cleanup_fds;
+               }
+       }
+
+       /* for now we don't support fd passing */
+       goto cleanup_fds;
+
+       ctx->recv_callback(ctx, ctx->recv_buf, received, ctx->private_data);
+       return;
+
+cleanup_fds:
+       close_fd_array(fds, num_fds);
+
        ctx->recv_callback(ctx, ctx->recv_buf, received, ctx->private_data);
 }