Fix sending fd through sendmsg/recvmsg ancillary data

[lttng-tools.git] / liblttkconsumerd / liblttkconsumerd.c

diff --git a/liblttkconsumerd/liblttkconsumerd.c b/liblttkconsumerd/liblttkconsumerd.c
index 1e86d28d0cc1ea9cf6afecfb22f554b040ebef13..1d69a4c463faffc1fa764141e287f725a625c535 100644 (file)
--- a/liblttkconsumerd/liblttkconsumerd.c
+++ b/liblttkconsumerd/liblttkconsumerd.c
@@ -28,6 +28,7 @@
 #include <sys/types.h>
 #include <unistd.h>
 #include <urcu/list.h>
+#include <assert.h>
 
 #include "libkernelctl.h"
 #include "liblttkconsumerd.h"
@@ -585,7 +586,6 @@ static int kconsumerd_consumerd_recv_fd(int sfd,
                struct pollfd *kconsumerd_sockpoll, int size,
                enum kconsumerd_command cmd_type)
 {
-       struct msghdr msg;
        struct iovec iov[1];
        int ret = 0, i, tmp2;
        struct cmsghdr *cmsg;
@@ -596,8 +596,15 @@ static int kconsumerd_consumerd_recv_fd(int sfd,
        /* the number of fds we are about to receive */
        nb_fd = size / sizeof(struct lttcomm_kconsumerd_msg);
 
+       /*
+        * Note: only supporting receiving one FD at a time for now.
+        * This code needs fixing if we wish to receive more (a single
+        * receive for the whole fd batch rather than one per fd).
+        */
+       assert(nb_fd == 1);
+
        for (i = 0; i < nb_fd; i++) {
-               memset(&msg, 0, sizeof(msg));
+               struct msghdr msg = { 0 };
 
                /* Prepare to receive the structures */
                iov[0].iov_base = &lkm;
@@ -631,12 +638,13 @@ static int kconsumerd_consumerd_recv_fd(int sfd,
                        kconsumerd_send_error(KCONSUMERD_ERROR_RECV_FD);
                        goto end;
                }
+
                /* if we received fds */
                if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
                        switch (cmd_type) {
                        case ADD_STREAM:
-                               DBG("kconsumerd_add_fd %s (%d)", lkm.path_name, (CMSG_DATA(cmsg)[0]));
-                               ret = kconsumerd_add_fd(&lkm, (CMSG_DATA(cmsg)[0]));
+                               DBG("kconsumerd_add_fd %s (%d)", lkm.path_name, ((int *) CMSG_DATA(cmsg))[0]);
+                               ret = kconsumerd_add_fd(&lkm, ((int *) CMSG_DATA(cmsg))[0]);
                                if (ret < 0) {
                                        kconsumerd_send_error(KCONSUMERD_OUTFD_ERROR);
                                        goto end;